Information processing device, information processing method, and program
19 claims: 4 independent, 15 dependent
- 1パケットの受信を第1条件に応じて途中で打ち切り、さらに第2条件に応じて前記パケットの受信開始から前記パケットの受信打ち切りまでの時間をキャリアセンスがアイドル状態だったものとして動作させる制御を行う制御部を具備する情報処理装置。
- 2前記制御部は、前記パケットの受信打ち切り後、前記第2条件を満たした場合には、IFS(Inter Frame Space)に相当する待ち時間を発生させないように制御する請求項1記載の情報処理装置。
- 3前記制御部は、前記パケットの受信打ち切り後、前記第2条件を満たした場合には、前記パケットの受信時においてキャリアセンスがBUSYに遷移した時刻から受信打ち切り時刻までの時間長をスロットタイムに換算してバックオフカウンタから減算する制御を行う請求項1記載の情報処理装置。
- 4前記制御部は、前記減算後の結果が負の値になる場合には、前記結果を0として扱う請求項3記載の情報処理装置。
- 5前記制御部は、前記減算後の結果が負の値になる場合には、前記減算前のバックオフカウンタを超えないように、当該負の値の分を正に折り返した値とする請求項3記載の情報処理装置。
- 6前記第1条件は、受信中の前記パケットにおける物理ヘッダ部を対象とするCRC計算結果が、前記物理ヘッダ内に記載されているCRC情報と一致しないことを含む、請求項1記載の情報処理装置。
- 7前記第1条件は、前記パケットにおける物理ヘッダ内にネットワークを識別するための識別子に関する情報が存在する場合に、前記識別子に関する情報が前記情報処理装置の属するネットワークのネットワーク識別子と異なることをさらに含む、請求項6記載の情報処理装置。
- 8前記第1条件は、受信中の前記パケットの、アンテナ入力換算でのプリアンブル相関器出力レベルが、前記パケットにおける物理ヘッダ内に記載された情報から導出される閾値を下回っていることをさらに含む、請求項6記載の情報処理装置。
- 9前記制御部は、前記パケットにおける物理ヘッダ内にネットワークを識別するための識別子に関する情報が存在し、前記識別子に関する情報が前記情報処理装置の属するネットワークのネットワーク識別子と一致する場合には、受信を打ち切ることなく継続する、請求項8記載の情報処理装置。
- 10前記制御部は、前記パケットにおける物理ヘッダ内に記載されたインデックスと予め共有されている閾値のテーブルとの対応付けに基づいて前記導出を行う請求項8記載の情報処理装置。
- 11前記制御部は、前記パケットにおける物理ヘッダ内に記載された値と、予め共有されている量子化および単位に関する情報とに基づく変換により前記導出を行う請求項8記載の情報処理装置。
- 12前記第2条件は、前記第1条件を含む請求項1記載の情報処理装置。
- 13前記制御部は、受信中の前記パケットの受信電力が予め定められたエネルギー検出閾値を下回ることを前記第2条件として、前記動作の要否を判断する請求項1記載の情報処理装置。
- 14前記制御部は、前記パケットの受信打ち切りを行った時点においてバーチャルキャリアセンスによる送信抑制がかかっていないことを前記第2条件として、前記動作の要否を判断する請求項1記載の情報処理装置。
- 15前記制御部は、前記パケットにおける物理ヘッダ部を対象とするCRC計算結果が、前記物理ヘッダ内に記載されているCRC情報と一致せず、かつ、前記パケットの、アンテナ入力換算でのプリアンブル相関器出力レベルが、適用されうるパケット検出閾値のうち最小のものを下回っていることを前記第2条件として、前記動作の要否を判断する請求項1記載の情報処理装置。
- 16前記制御部は、前記パケットの受信打ち切り後に前記第2条件を満たさない場合には、当該パケット転送の継続期間中の前記情報処理装置からの送信を禁止する制御を行う請求項1記載の情報処理装置。
- 17前記制御部は、前記パケットの受信打ち切り後に前記第2条件を満たさず、当該パケット転送の継続期間中の前記情報処理装置からの送信を禁止した場合において、前記情報処理装置宛てであり、かつ、応答を要求するフレームを受信したときには、前記フレームに対する応答を送信する制御を行う請求項16記載の情報処理装置。
- 18パケットの受信を第1条件に応じて途中で打ち切る第1手順と、 第2条件に応じて前記パケットの受信開始から前記パケットの受信打ち切りまでの時間をキャリアセンスがアイドル状態だったとして動作する第2手順とを具備する情報処理方法。
- 19パケットの受信を第1条件に応じて途中で打ち切る第1手順と、 第2条件に応じて前記パケットの受信開始から前記パケットの受信打ち切りまでの時間をキャリアセンスがアイドル状態だったとして動作する第2手順とをコンピュータに実行させるプログラム。
Independent claims19
600 paragraphs, as filed
The present technology relates to an information processing device. More specifically, the present invention relates to an information processing device and an information processing method for exchanging information using wireless communication, and a program for causing a computer to execute the method.
Conventionally, there is a wireless communication technology for exchanging information using wireless communication. For example, a communication method (for example, an autonomous decentralized wireless network) that autonomously interconnects with an adjacent information processing device has been proposed. By using this communication method, information can be exchanged between two information processing devices by using wireless communication without connecting by a wired line.
Further, in the autonomous decentralized wireless network, carrier sense is adopted as an arbitration method for avoiding packet collision during communication between each information processing device.
For example, a wireless communication device that dynamically sets a carrier sense level threshold value based on desired wave power to suppress transmission has been proposed (see, for example, Patent Document 1).
<p><patcit num="1"><text>JP-A-2007-142722</text></patcit></p>
<p> In the above-mentioned conventional technique, even if the received signal strength is equal to or less than the carrier sense level threshold value, transmission can be prevented when the desired wave to interference power ratio is likely to cause a transmission error.</p><p> However, if the number of information processing devices constituting the network increases, excessive transmission suppression may occur and the transmission efficiency of the entire system may decrease. Therefore, it is important to maintain communication quality and use wireless resources efficiently.</p><p> This technology was created in view of this situation, and aims to efficiently use wireless resources.</p>
<p> The present technology has been made to solve the above-mentioned problems, and the first aspect thereof is that the reception of the packet is interrupted in the middle according to the first condition, and the packet is further processed according to the second condition. An information processing device including a control unit that controls the time from the start of reception to the termination of reception of the packet as if the carrier sense was idle, an information processing method thereof, and a program for causing a computer to execute the method. .. As a result, packet reception is terminated in the middle according to the first condition, and the time from the start of packet reception to the packet reception termination is operated as if the carrier sense was idle according to the second condition. Bring.</p><p> Further, in the first aspect, the control unit controls so as not to generate a waiting time corresponding to IFS (Inter Frame Space) when the second condition is satisfied after the reception of the packet is terminated. You may do so. As a result, when the second condition is satisfied after the reception of the packet is terminated, the operation of controlling so as not to generate the waiting time corresponding to IFS is brought about.</p><p> Further, in the first aspect, if the second condition is satisfied after the reception of the packet is cut off, the control unit starts from the time when the carrier sense transitions to BUSY at the time of receiving the packet to the reception cutoff time. The time length up to is converted into the slot time and subtracted from the backoff counter. As a result, if the second condition is satisfied after the packet reception is cut off, the time length from the time when the carrier sense transitions to BUSY to the reception cutoff time at the time of packet reception is converted into slot time and the backoff counter It has the effect of subtracting from.</p><p> Further, in this first aspect, the control unit may treat the result as 0 when the result after the subtraction becomes a negative value. As a result, when the result after subtraction becomes a negative value, the result is treated as 0.</p><p> Further, in the first aspect, when the result after the subtraction becomes a negative value, the control unit positively corrects the negative value so as not to exceed the backoff counter before the subtraction. The value may be folded back to. As a result, when the result after subtraction becomes a negative value, the negative value is set as a positively folded value so as not to exceed the backoff counter before the subtraction.</p><p> Further, in the first aspect, the first condition includes that the CRC calculation result for the physical header portion in the packet being received does not match the CRC information described in the physical header. You may do so. This has the effect that the first condition is that the CRC calculation result for the physical header portion of the packet being received does not match the CRC information described in the physical header.</p><p> Further, in the first aspect, the first condition is that when the information regarding the identifier for identifying the network exists in the physical header in the packet, the information regarding the identifier is the network to which the information processing apparatus belongs. It may further include things that are different from the network identifier. This has the effect that when the information about the identifier for identifying the network exists in the physical header of the packet, the first condition is that the information about the identifier is different from the network identifier of the network to which the own device belongs. ..</p><p> Further, in the first aspect, the first condition is a threshold value at which the preamble correlator output level of the packet being received in terms of antenna input is derived from the information described in the physical header of the packet. It may be further included that it is below. As a result, the first condition is that the preamble correlator output level of the packet being received in terms of antenna input is lower than the threshold value derived from the information described in the physical header of the packet. Bring.</p><p> Further, in the first aspect, the control unit has information on an identifier for identifying a network in the physical header in the packet, and the information on the identifier is the network identifier of the network to which the information processing apparatus belongs. If they match, the reception may be continued without being interrupted. As a result, if the information about the identifier for identifying the network exists in the physical header of the packet and the information about the identifier matches the network identifier of the network to which the own device belongs, the reception is continued without being interrupted. Brings action.</p><p> Further, in the first aspect, the control unit may perform the derivation based on the association between the index described in the physical header in the packet and the threshold table shared in advance. .. This has the effect of deriving the index based on the association between the index described in the physical header and the table of threshold values shared in advance.</p><p> Further, in the first aspect, the control unit performs the above derivation by conversion based on the value described in the physical header in the packet and the information regarding the quantization and the unit shared in advance. May be good. This has the effect of deriving it by conversion based on the values described in the physical header and the information about the quantization and units shared in advance.</p><p> Further, in the first aspect, the second condition may include the first condition. This brings about the effect of using the second condition including the first condition.</p><p> Further, in the first aspect, the control unit determines the necessity of the operation on the condition that the received power of the packet being received is lower than the predetermined energy detection threshold value as the second condition. You may. As a result, the second condition is that the received power of the packet being received falls below a predetermined energy detection threshold value.</p><p> Further, in the first aspect, the control unit determines the necessity of the operation on the condition that the transmission suppression by the virtual carrier sense is not applied at the time when the reception of the packet is terminated. You may do so. As a result, the second condition is that the transmission is not suppressed by the virtual carrier sense at the time when the reception of the packet is terminated.</p><p> Further, in the first aspect, the control unit does not match the CRC calculation result for the physical header unit in the packet with the CRC information described in the physical header, and the packet The necessity of the above operation may be determined on the condition that the preamble correlator output level in terms of antenna input is lower than the minimum applicable packet detection threshold. As a result, the CRC calculation result for the physical header part of the packet does not match the CRC information described in the physical header, and the preamble correlator output level is the minimum of the applicable packet detection thresholds. The second condition is that it is less than the one, and it has the effect of judging the necessity of operation.</p><p> Further, in the first aspect, if the second condition is not satisfied after the reception of the packet is terminated, the control unit prohibits transmission from the information processing apparatus during the duration of the packet transfer. May be done. As a result, if the second condition is not satisfied after the reception of the packet is terminated, the transmission from the own device during the duration of the packet transfer is prohibited.</p><p> Further, in the first aspect, when the control unit does not satisfy the second condition after the reception of the packet is terminated and the transmission from the information processing device during the duration of the packet transfer is prohibited, the above When a frame that is addressed to the information processing device and requests a response is received, control may be performed to transmit a response to the frame. As a result, when the second condition is not satisfied after the packet reception is terminated and transmission from the own device is prohibited during the duration of the packet transfer, a frame addressed to the own device and requesting a response is received. Occasionally, it has the effect of sending a response to that frame.</p>
<p> According to this technology, it is possible to achieve an excellent effect that wireless resources can be used efficiently. The effects described herein are not necessarily limited, and may be any of the effects described in the present disclosure.</p>
<figref num="1">It is a figure which shows the system configuration example of the communication system 10 in the 1st Embodiment of this technology.</figref><figref num="2">It is a figure which shows the system configuration example of the communication system 10 in the 1st Embodiment of this technology.</figref><figref num="3">It is a figure which shows the system configuration example of the communication system 10 in the 1st Embodiment of this technology.</figref><figref num="4">It is a figure which shows an example of the transmission / reception processing by each information processing apparatus which constitutes the communication system 10 in 1st Embodiment of this technology in time series.</figref><figref num="5">It is a block diagram which shows the functional structure example of the information processing apparatus 100 in 1st Embodiment of this technology.</figref><figref num="6">It is a sequence chart which shows the communication processing example between each apparatus which constitutes the communication system 10 in 1st Embodiment of this technique.</figref><figref num="7">It is a figure which shows an example of the format of the PPDU exchanged between each apparatus constituting the communication system 10 in the 1st Embodiment of this technique.</figref><figref num="8">It is a sequence chart which shows the example of the connection processing between each apparatus constituting the communication system 10 in the 1st Embodiment of this technique.</figref><figref num="9">It is a figure which shows typically an example of the contents of the setting information list 161 stored in the memory of the information processing apparatus 200 in 1st Embodiment of this technique.</figref><figref num="10">It is a flowchart which shows an example of the processing procedure of the physical header parameter determination processing by the information processing apparatus 200 in the 1st Embodiment of this technique.</figref><figref num="11">It is a figure which shows the structural example of the correlator provided in the information processing apparatus 200 in 1st Embodiment of this technique.</figref><figref num="12">It is a figure which shows the system configuration example of the communication system 10 in the 1st Embodiment of this technology.</figref><figref num="13">It is a figure which shows the system configuration example of the communication system 10 in the 1st Embodiment of this technology.</figref><figref num="14">It is a figure which shows an example of the beacon frame format exchanged between each apparatus constituting the communication system 10 in the 1st Embodiment of this technique.</figref><figref num="15">It is a sequence chart which shows the example of the physical header parameter sharing processing among the devices constituting the communication system 10 in the 1st Embodiment of this technique.</figref><figref num="16">It is a flowchart which shows an example of the processing procedure of the physical header use determination process by the information processing apparatus 100 in the 1st Embodiment of this technique.</figref><figref num="17">It is a flowchart which shows an example of the processing procedure of the transmission / reception processing by the information processing apparatus 100 in the 1st Embodiment of this technique.</figref><figref num="18">It is a flowchart which shows the packet detection determination processing among the transmission / reception processing by the information processing apparatus 100 in 1st Embodiment of this technique.</figref><figref num="19">It is a flowchart which shows an example of the processing procedure of the transmission / reception processing by the information processing apparatus 100 in the 2nd Embodiment of this technique.</figref><figref num="20">It is a figure which shows an example of the format of the PPDU exchanged between the devices which make up the communication system 10 in the 3rd Embodiment of this technique.</figref><figref num="21">It is a figure which shows an example of the format of the PPDU exchanged between the devices constituting the communication system 10 in the 4th Embodiment of this technique.</figref><figref num="22">It is a flowchart which shows the packet detection determination processing among the transmission / reception processing by the information processing apparatus 100 in 4th Embodiment of this technology.</figref><figref num="23">It is a figure which shows an example of the beacon frame format exchanged between each apparatus constituting the communication system 10 in 5th Embodiment of this technique.</figref><figref num="24">It is a sequence chart which shows the example of the connection processing between each apparatus constituting the communication system 10 in 5th Embodiment of this technique.</figref><figref num="25">It is a flowchart which shows the packet detection determination processing among the transmission / reception processing by the information processing apparatus 100 in 5th Embodiment of this technology.</figref><figref num="26">It is a flowchart which shows the packet detection determination processing among the transmission / reception processing by the information processing apparatus 100 in 6th Embodiment of this technique.</figref><figref num="27">It is a figure which shows the structural example of the correlator provided in the information processing apparatus 100 in the 6th Embodiment of this technique.</figref><figref num="28">It is a figure which shows the system configuration example of the communication system 50 in 7th Embodiment of this technique.</figref><figref num="29">It is a sequence chart which shows the communication processing example between each apparatus which constitutes the communication system 50 in 7th Embodiment of this technique.</figref><figref num="30">It is a sequence chart which shows the communication processing example between each apparatus which constitutes the communication system 50 in 8th Embodiment of this technique.</figref><figref num="31">It is a figure which shows an example of the format of the PPDU exchanged between the devices which make up the communication system 10 in the 9th Embodiment of this technique.</figref><figref num="32">It is a figure which shows an example of the beacon frame format exchanged between each apparatus constituting the communication system 10 in the 9th Embodiment of this technique.</figref><figref num="33">It is a figure which shows the flow of the back-off processing in the IEEE802.11 standard.</figref><figref num="34">It is a figure which shows the flow of the back-off processing by the information processing apparatus 100 in the 9th Embodiment of this technique.</figref><figref num="35">It is a figure which shows the flow of the back-off processing by the information processing apparatus 100 in the 9th Embodiment of this technique.</figref><figref num="36">It is a flowchart which shows an example of the processing procedure of the physical header use determination process by the information processing apparatus 100 in the 9th Embodiment of this technique.</figref><figref num="37">It is a flowchart which shows an example of the processing procedure of the transmission / reception processing by the information processing apparatus 100 in the 9th Embodiment of this technique.</figref><figref num="38">It is a figure which shows the relation example (processing classification table) of the processing performed by the information processing apparatus 100 and the physical header in the 9th Embodiment of this technique.</figref><figref num="39">It is a flowchart which shows the packet detection / reception determination processing in the transmission / reception processing by the information processing apparatus 100 in the 9th Embodiment of this technology.</figref><figref num="40">It is a figure which shows an example of the format of the PPDU exchanged between the devices which make up the communication system 10 in the tenth embodiment of this technique.</figref><figref num="41">It is a figure which shows the relation example (processing classification table) of the processing performed by the information processing apparatus 100 and the physical header in the tenth embodiment of this technique.</figref><figref num="42">It is a flowchart which shows the packet detection / reception determination processing in the transmission / reception processing by the information processing apparatus 100 in the tenth embodiment of this technique.</figref><figref num="43">It is a figure which shows an example of the format of the PPDU exchanged between the devices which make up the communication system 10 in 11th Embodiment of this technique.</figref><figref num="44">It is a figure which shows an example of the beacon frame format exchanged between each apparatus constituting the communication system 10 in 11th Embodiment of this technique.</figref><figref num="45">It is a flowchart which shows an example of the processing procedure of the use physical header determination processing by the information processing apparatus 100 in eleventh embodiment of this technique.</figref><figref num="46">It is a figure which shows the relationship example (processing classification table) of the processing performed by the information processing apparatus 100 and the physical header in the eleventh embodiment of this technique.</figref><figref num="47">It is a figure which shows an example of the format of the PPDU exchanged between the devices constituting the communication system 10 in the twelfth embodiment of this technique.</figref><figref num="48">It is a flowchart which shows an example of the processing procedure of the physical header parameter determination processing by the information processing apparatus 200 in the twelfth embodiment of this technique.</figref><figref num="49">It is a figure which shows an example of the beacon frame format exchanged between each apparatus constituting the communication system 10 in the twelfth embodiment of this technique.</figref><figref num="50">It is a figure which shows the relation example (processing classification table) of the processing performed by the information processing apparatus 100 and the physical header in the twelfth embodiment of this technique.</figref><figref num="51">It is a block diagram which shows an example of the schematic structure of a smartphone.</figref><figref num="52">It is a block diagram which shows an example of the schematic structure of a car navigation device.</figref><figref num="53">It is a block diagram which shows an example of the schematic structure of a wireless access point.</figref>
Hereinafter, embodiments for carrying out the present technology (hereinafter referred to as embodiments) will be described. The explanation will be given in the following order. 1. First embodiment (Example of providing a Link Strength Category field in the SIGNAL field of the IEEE802.11 standard and setting packet detection conditions according to the information processing device) 2. Second embodiment (packet) If the detection judgment result is only energy detection and transmission suppression is set, no transmission is performed. Example) 3. Third embodiment (Link Strength Category field, IEEE 802.11 standard Service field Example provided in) 4. Fourth embodiment (example in which a plurality of preamble sequences having different detection thresholds are used on the transmitting side and the receiving side switches the preamble correlation detector applied by RSSI) 5. Fifth implementation (Example in which the master station selects the physical header used by the subordinate information processing device) 6. The sixth embodiment (Generation of multiple PLCP preambles for distinction is not a completely separate series, but Example of processing a part of the original series to generate it) 7. 7th embodiment (example of direct communication between slave stations) 8. 8th embodiment (example of the slave station determining the physical header parameters to be used between direct links) 9. 9th embodiment Embodiment (Example of storing information about BSS identifier in the SIGNAL field of IEEE 802.11 standard) 10. 10th Embodiment (Example of defining multiple Preamble series and using COLOR information together) 11. 11th embodiment (example of omitting the determination process of physical header parameters) 12. 12th embodiment (example of providing a field for storing information about the BSS identifier in the SIGNAL field of the IEEE802.11 standard) 13. Application example
<1. First Embodiment> [Communication system configuration example]
FIG. 1 is a diagram showing a system configuration example of the communication system 10 according to the first embodiment of the present technology.
The communication system 10 is composed of information processing devices 100 to 103, information processing devices 200, and 201.
The information processing devices 100 to 103 are, for example, portable information processing devices having a wireless communication function. Here, the portable information processing device is, for example, an information processing device such as a smartphone, a mobile phone, or a tablet terminal. Further, the information processing devices 100 to 103 shall be provided with, for example, a communication function compliant with the wireless LAN (Local Area Network) standard of IEEE (Institute of Electrical and Electronic Engineers) 802.11. As this wireless LAN, for example, Wi-Fi (Wireless Fidelity), Wi-Fi Direct, Wi-Fi CERTIFIED Miracast specification (technical specification name: Wi-Fi Display) can be used. In addition, wireless communication using another communication method may be performed.
Further, the information processing devices 200 and 201 are, for example, fixed type information processing devices having a wireless communication function. Here, the fixed type information processing device is, for example, an information processing device such as an access point or a base station. Further, the information processing devices 200 and 201 are provided with, for example, a communication function compliant with the wireless LAN standard of IEEE 802.11, as in the information processing devices 100 to 103. In addition, wireless communication using another communication method may be performed.
Further, the information processing devices 200 and 201 function as master stations, and the information processing devices 100 to 103 function as slave stations. That is, in the first embodiment of the present technology, an example of communication between a master station and a slave station is shown in a star topology composed of a master station and its subordinate slave stations. Further, in the first embodiment of the present technology, a communication example is shown in which the transmission of the subordinate slave station limits the transmission destination to the master station.
Further, the information processing devices 100 and 102 and the information processing devices 200 and 201 are provided with specific functions (specific functions shown in each embodiment of the present technology). On the other hand, it is assumed that the information processing devices 101 and 103 do not have a specific function. An information processing device that does not have a specific function in this way is referred to as a legacy device. The specific function will be described in each embodiment of the present technology. The legacy device can be, for example, an information processing device having a communication function compliant with the wireless LAN standard of IEEE802.11a, IEEE802.11g, IEEE802.11n, or IEEE802.11ac.
Further, in the first embodiment of the present technology, an example of communication between each device when the information processing device 100 and the information processing device 101 are connected and the information processing device 201 and the information processing device 102 are connected is shown. ..
Although FIG. 1 shows an example in which the communication system 10 is configured by four slave stations (information processing devices 100 to 103), the number of slave stations (information processing devices) is not limited to four. That is, the embodiment of the present technology can be applied to a communication system composed of 3 or 5 or more slave stations (information processing devices).
Further, as for the relationship between two information processing devices that perform communication, one of them may be a master station and the other may be a slave station. Further, the connection between the two information processing devices may be a direct communication connection between the slave stations.
Here, in an autonomous decentralized wireless network, a method called carrier sense is generally adopted as an arbitration mechanism for avoiding packet collisions. The carrier sense monitors the surrounding wireless condition for a certain period of time before transmitting, and confirms whether or not there is another information processing device performing transmission. Then, when the received power equal to or higher than the threshold value is detected during the confirmation, the radio is determined to be in a busy state, the transmission operation is stopped, and the transmission is not performed.
There are two types of detection algorithms for carrier sense: preamble detection, which detects by comparing the power of the correlator output of a specific preamble, and energy detection, which detects by comparing the power of the received signal itself. A detection algorithm is also used. In the following, unless otherwise specified, the two types of detection algorithms will be collectively referred to as carrier sense.
As described above, when the number of information processing devices in the network increases, the carrier sense method described above may cause excessive transmission suppression and reduce the transmission efficiency of the entire system.
Here, an example of the positional relationship that causes such a situation will be described with reference to FIG. In FIG. 1, there are two master stations (information processing devices 200 and 201) and four slave stations (information processing devices 100 to 103). Further, in FIG. 1, the information processing devices 100 and 101 are connected to the information processing device 200, and the information processing devices 102 and 103 are connected to the information processing device 201 so that they can communicate with each other. In FIG. 1, the connection relationship between the devices is schematically shown by a dotted line.
Further, in FIG. 1, it is assumed that the information processing devices 100 to 103, 200, and 201 are in a positional relationship in which transmissions from all the information processing devices can be detected by carrier sense.
Here, for example, it is assumed that the information processing apparatus 100 transmits to the information processing apparatus 200 and the information processing apparatus 102 transmits to the information processing apparatus 201.
[Example of carrier sense detection range]
2 and 3 are diagrams showing a system configuration example of the communication system 10 according to the first embodiment of the present technology. 2 and 3 show an example in which the carrier sense detection ranges of the information processing devices are superimposed in the example shown in FIG.
Further, in FIGS. 2 and 3, the carrier sense detection ranges 11 to 16 of the information processing devices 100, 102, 200, and 201 are schematically shown by dotted circles.
Specifically, in FIGS. 2 and 3, the carrier sense detection range 11 indicates the carrier sense detection range of the information processing device 200, and the carrier sense detection range 12 indicates the carrier sense detection range of the information processing device 201.
Further, in FIG. 2, the carrier sense detection range 13 indicates the carrier sense detection range of the information processing apparatus 100, and the carrier sense detection range 14 indicates the carrier sense detection range of the information processing apparatus 102.
Further, in FIG. 3, the carrier sense detection range 15 indicates the carrier sense detection range of the information processing apparatus 100 after the carrier sense detection range 13 shown in FIG. 2 is changed. Further, the carrier sense detection range 16 indicates the carrier sense detection range of the information processing apparatus 102 after the carrier sense detection range 14 shown in FIG. 2 is changed.
As described above, the carrier sense is an example of an arbitration mechanism for avoiding packet collision, and suppresses transmission depending on the presence or absence of another information processing device that is transmitting. Further, the carrier sense detection range is determined according to a threshold value used when detecting a transmission signal from another information processing device.
Here, for example, it is assumed that the information processing apparatus 100 performs carrier sense for transmission while the information processing apparatus 102 is transmitting to the information processing apparatus 201. For example, when the information processing apparatus 100 detects the transmission of the information processing apparatus 102, the transmission is suppressed, and the transmission cannot be performed until the transmission of the information processing apparatus 102 is completed.
However, even if the information processing device 100 transmits to the information processing device 200 during the transmission of the information processing device 102, the information processing device 200 and the information processing device 201 on the receiving side still receive the desired wave and the interference wave. Depending on the ratio with, it may be possible to receive. The desired wave is a radio wave from the information processing device 100 to the information processing device 200 and a radio wave from the information processing device 102 to the information processing device 201. The interference wave is a radio wave from the information processing device 100 to the information processing device 201 and a radio wave from the information processing device 102 to the information processing device 200.
For example, as shown in FIG. 1, when the distance between the information processing device 102 and the information processing device 200 is larger than the distance between the information processing device 100 and the information processing device 200, there is a possibility of reception. Is expected to increase. Therefore, it is important to ensure collision avoidance and to improve the efficiency of the carrier sense mechanism that suppresses transmission when potential improvement can be achieved.
For example, as shown in FIG. 3, it is assumed that the carrier sense detection thresholds of the information processing apparatus 100 and the information processing apparatus 102 are changed and set so high that they cannot detect each other's transmitted radio waves. In this case, since the information processing device 100 does not detect the transmission from the information processing device 102, each of the information processing device 100 and the information processing device 102 can transmit at the same time and use the wireless resources at the same time. become.
However, even if the transmission opportunity of the information processing device on the transmitting side increases, if the information processing device on the receiving side does not properly stand by at that opportunity, the transmission may not succeed and no gain may be generated. An example of this is shown in FIG.
FIG. 4 is a diagram showing an example of transmission / reception processing by each information processing device constituting the communication system 10 in the first embodiment of the present technology in chronological order.
FIG. 4 shows an example in which the information processing apparatus 100 transmits to the information processing apparatus 200 while the information processing apparatus 102 transmits to the information processing apparatus 201 in the example shown in FIG.
For example, as shown in FIG. 3, the information processing device 102 exists in the carrier sense detection range 11 of the information processing device 200. Therefore, when the information processing device 200 detects the transmission (21) of the information processing device 102 first and starts the reception on the interfering side (22), the information processing device 200 newly provides a transmission opportunity. The transmission (23) from the obtained information processing device 100 cannot be received (22). As described above, even if the ratio of the signal wave to the interference wave is sufficiently high, reception may fail.
Therefore, for example, it is conceivable to raise the carrier sense detection threshold value of the information processing apparatus 200. However, since the master station needs to have a plurality of information processing devices under its control and stand by at the same time, if the master station uniformly raises the carrier sense detection threshold, communication from the subordinate information processing device to be received is performed. May not be detected properly. Therefore, it is desirable to change the carrier sense detection threshold only when it is really necessary or when improvement is definitely expected.
Therefore, in the embodiment of the present technology, an example is shown in which the radio resources are appropriately reused when the side effects caused by increasing the carrier sense detection threshold can be minimized and improved. In this case, the reception level of the transmitted / received packet from the third party can also be observed.
Specifically, in the embodiment of the present technology, the information processing device on the transmitting side changes the content of the PLCP (Physical Layer Convergence Protocol) header according to the communication quality with the destination (for example, the amount of propagation attenuation). To. Further, the information processing device on the receiving side uses a part of the received contents of the PLCP header to change the packet detection threshold to be applied so that only a desired packet can be detected.
Here, the PLCP transmits the part that needs to be received in common at a constant speed modulation regardless of the transmission rate, and transmits the subsequent data part by various methods depending on the device and the situation at that time. Means a protocol for encapsulating MAC frames.
For example, PLCP preambles are used to detect packets and estimate propagation path gain. In addition, the PLCP header is used to convey information such as modulation of the data unit and frame length.
[Configuration example of information processing device]
FIG. 5 is a block diagram showing a functional configuration example of the information processing apparatus 100 according to the first embodiment of the present technology. Since the functional configurations (functional configurations related to wireless communication) of the information processing devices 101 to 103, 200, and 201 are substantially the same as those of the information processing device 100, the description thereof is omitted here.
The information processing device 100 includes a data processing unit 110, a transmission processing unit 120, a modulation / demodulation unit 130, a wireless interface unit 140, an antenna 141, a control unit 150, and a memory 160.
The data processing unit 110 processes various data based on the control of the control unit 150. For example, the data processing unit 110 creates the text of various data frames, data packets, and the like. For example, when performing a transmission operation, the data processing unit 110 creates various data frames and data packets in response to a request from the upper layer and supplies them to the transmission processing unit 120. Further, for example, when performing a reception operation, the data processing unit 110 processes and analyzes various data frames and data packets supplied from the transmission processing unit 120.
The transmission processing unit 120 performs various transmission processes based on the control of the control unit 150. For example, when performing a transmission operation, the transmission processing unit 120 performs processing such as adding a header for media access control and adding an error detection code to the packet generated by the data processing unit 110. For example, the transmission processing unit 120 performs processing such as addition of a MAC header for MAC (Media Access Control address) and addition of an error detection code to the packet generated by the data processing unit 110. Then, the transmission processing unit 120 supplies the processed data to the modulation / demodulation unit 130.
When carrier sense is used, the transmission processing unit 120 calculates the NAV (Network Allocation Vector) to be added. Here, as described above, carrier sense is an example of an arbitration mechanism for avoiding packet collisions. The transmission suppression time is described in the content of a wireless packet, and transmission suppression is applied to the information processing device that has received the packet. It is to be set. In addition, NAV means the transmission suppression time.
Further, for example, when performing a reception operation, the transmission processing unit 120 processes the bit string supplied from the modulation / demodulation unit 130 in the reverse manner of the transmission operation (for example, packet error detection, MAC header analysis, and removal). )I do. Then, when the transmission processing unit 120 confirms that there is no error in the data frame based on the error detection code, the transmission processing unit 120 supplies various data frames to the data processing unit 110.
In addition, the transmission processing unit 120 performs virtual carrier sense processing. In this case, if NAV is set in the header of the received packet and transmission suppression is applied, the transmission processing unit 120 notifies the control unit 150 to that effect.
The modulation / demodulation unit 130 performs modulation / demodulation processing and the like based on the control of the control unit 150. For example, when performing a transmission operation, the modulation / demodulation unit 130 encodes, interleaves, modulates, and PLCP headers for the input bit string from the transmission processing unit 120 based on the coding and modulation scheme set by the control unit 150. , Add PLCP preamble. Then, the modulation / demodulation unit 130 generates a data symbol string and supplies it to the wireless interface unit 140.
Further, for example, when performing a reception operation, the modulation / demodulation unit 130 performs a process opposite to that at the time of the transmission operation on the input from the wireless interface unit 140, and supplies the result to the transmission processing unit 120. Further, the modulation / demodulation unit 130 performs carrier sense processing. In this case, when the modulation / demodulation unit 130 detects the received power equal to or higher than the threshold value or detects the value of the preamble correlation equal to or higher than the predetermined output, the modulation / demodulation unit 130 determines that the radio is in a busy state, and the control unit determines that fact. Notify 150.
The wireless interface unit 140 is an interface for connecting to another information processing device to transmit and receive various information. For example, when performing a transmission operation, the radio interface unit 140 converts the input from the modulation / demodulation unit 130 into an analog signal, performs amplification, filtering, and frequency up-conversion, and transmits the radio signal from the antenna 141. Further, for example, when performing a receiving operation, the wireless interface unit 140 performs a process opposite to that during the transmitting operation on the input from the antenna 141, and supplies the result to the modulation / demodulation unit 130.
The control unit 150 controls the reception operation and the transmission operation of each of the data processing unit 110, the transmission processing unit 120, the modulation / demodulation unit 130, and the wireless interface unit 140. For example, the control unit 150 transfers information between each unit, sets communication parameters, and schedules packets in the transmission processing unit 120. Further, for example, when the control unit 150 receives the notification of the carrier sense result from the modulation / demodulation unit 130 and the transmission processing unit 120, the control unit 150 performs each process related to the setting and cancellation of the transmission suppression based on the notification.
Further, for example, the control unit (corresponding to the control unit 150) of the information processing device 200 uses wireless communication for physical headers (for example, PLCP preamble, PLCP header) used for packets transmitted by other information processing devices. And control the transmission to other information processing devices.
Further, for example, the control unit 150 controls to select one from a plurality of physical header candidates (for example, PLCP preamble, PLCP header) and use it for a packet to be transmitted. Here, the plurality of physical header candidates correspond to information regarding a plurality of physical headers (for example, PLCP preamble, PLCP header) transmitted from the information processing apparatus 200.
Further, for example, the control unit of the information processing apparatus 200 transmits the packet detection conditions (for example, each detection threshold value of the PLCP preamble) used by the other information processing apparatus to the other information processing apparatus by using wireless communication. Take control.
Further, for example, the control unit 150 selects one of a plurality of packet detection conditions (for example, each detection threshold value of the PLCP preamble) for a plurality of packets transmitted from the information processing apparatus 200 using wireless communication. Control to use. Here, the plurality of packet detection conditions correspond to the plurality of packet detection conditions transmitted from the information processing apparatus 200.
Further, for example, the control unit 150 controls to select and execute one of a plurality of reception operations for a plurality of packets transmitted from the information processing device 200 by using wireless communication. The plurality of receiving operations will be described in the first to eleventh embodiments of the present technology.
The memory 160 has a role as a work area for data processing by the control unit 150 and a function as a storage medium for holding various data. As the memory 160, for example, a storage medium such as a non-volatile memory, a magnetic disk, an optical disk, or an MO (Magneto Optical) disk can be used. As the non-volatile memory, for example, EEPROM (Electrically Erasable Programmable Read-Only Memory) and EPROM (Erasable Programmable ROM) can be used. Further, as the magnetic disk, for example, a hard disk or a disk-type magnetic disk can be used. Further, as the optical disk, for example, a CD (Compact Disc), a DVD-R (Digital Versatile Disc Recordable), and a BD (Blu-Ray Disc (registered trademark)) can be used.
Further, in each embodiment of the present technology, the uplink transmission from the information processing device 100 to the information processing device 200 and the uplink transmission from the information processing device 102 to the information processing device 201 are simultaneously (or substantially simultaneously). An example in which each transmission is successful when performed will be described. In addition, the embodiment of the present technology can be applied to transmissions between information processing devices other than these transmissions.
[Communication example]
FIG. 6 is a sequence chart showing an example of communication processing between the devices constituting the communication system 10 according to the first embodiment of the present technology.
FIG. 6 shows an example of communication processing in the case of performing uplink transmission from the information processing device 100 to the information processing device 200. The same applies to the relationship between other information processing devices (for example, between the information processing device 102 and the information processing device 201).
First, a connection process is performed between the information processing device 100 and the information processing device 200 (401). The connection process will be described in detail with reference to FIG.
Subsequently, the information processing apparatus 200 performs a physical header parameter determination process (402). The physical header parameter determination process will be described in detail with reference to FIG.
Subsequently, the physical header parameter sharing process is performed between the information processing device 100 and the information processing device 200 (403). That is, a process for sharing the physical header parameter determined by the physical header parameter determination process between the information processing device 100 and the information processing device 200 is performed (403).
Subsequently, the information processing apparatus 200 performs transmission / reception processing (405).
Further, information report processing apparatus 100 performs use physical header determination process (404). The physical header used determination process will be described in detail with reference to FIG. Subsequently, the information processing apparatus 100 performs transmission / reception processing (406).
[PPDU (Presentation-layer Protocol Data Unit) format example]
FIG. 7 is a diagram showing an example of the format of the PPDU exchanged between the devices constituting the communication system 10 in the first embodiment of the present technology.
The PPDU is composed of Preamble301, SIGNAL302, Extension303, Service304, MPDU (MAC Protocol Data Unit) 305, and FCS (Frame Check Sequence) 306.
Preamble301 refers to the part corresponding to IEEE802.11 L-STF (Legacy Short Training Field) and L-LTF (Legacy Long Training Field) shown in c of FIG. In addition, Preamble301 has a format compatible with them.
SINGAL302 refers to the IEEE802.11 L-SIG (Legacy SIGNAL) and HT-SIG (High Throughput SIGNAL) fields shown in c in FIG. Note that c in FIG. 7 shows the HT Mixed Mode Format of IEEE 802.11n as an example. HT-SIG may be replaced with a VHT-SIG-A (Very High Throughput SIGNAL-A) field in IEEE802.11ac and a HE-SIG (High Efficiency SIGNAL) field in IEEE802.11ax.
Depending on the format, additional fields (HT-STF, HT-LTF, VHT-STF, VHT-LTF, VHT-SIG-B) may be added after that.
Here, in the first embodiment of the present technology, a "Link Strength Category field" is newly prepared as a part of the field of SIGNAL 302 which is the PLCP header part of the physical header. That is, a new "Link Strength Category field" is provided in the part of the PLCP header that is treated as Reserved in SIGNAL 302. Then, each information processing device (other than the legacy device) changes the "Link Strength Category field" according to the quality of the link with the destination at the time of transmission.
Note that a in FIG. 7 shows an example in which 1 is stored in the Link Strength Category field. In addition, b in FIG. 7 shows an example of storing 0 in the Link Strength Category field. As described above, in a and b of FIG. 7, an example in which the value of two stages (0 or 1) is stored in the "Link Strength Category field" is shown, but the value of three or more stages may be stored.
As described above, in the first embodiment of the present technology, the "Link Strength Category field" is provided in the portion of the SIGNAL 302 that is treated as Reserved. As a result, the specific function in the first embodiment of the present technology can be realized without hindering the reception of the legacy device.
Further, in the first embodiment of the present technology, the physical header of Link Strength Category field = 0 is referred to as "physical header for long distance". Further, the physical header of Link Strength Category field = 1 is referred to as "physical header for short distance". The physical header transmitted from the Legacy device shall be treated as a "physical header for a long distance".
The information processing device (other than the legacy device) that receives the packet having the Link Strength Category field changes the detection threshold to be applied according to the content (0 or 1) of the Link Strength Category field.
[Connection processing example]
FIG. 8 is a sequence chart showing an example of connection processing between the devices constituting the communication system 10 according to the first embodiment of the present technology.
FIG. 8 shows an example of processing until the connection between the information processing device 100 and the information processing device 200 is established. The same applies to the relationship between the information processing device 102 and the information processing device 201.
At the time of attempting the connection, the link quality between the information processing device 100 and the information processing device 200 is unknown. Therefore, in order to make a reliable connection, the information processing apparatus 100 does not adjust the threshold value and uses the preamble detection threshold value and the physical header equivalent to those of the legacy apparatus.
That is, the information processing device 100 sets the preamble detection threshold value to the same value as the legacy operation (operation of the legacy device) (411). Further, the information processing device 100 sets the physical header in the same format as the legacy operation (operation of the legacy device) (412).
Further, the information processing device 200 sets the physical header in the same format as the legacy operation (operation of the legacy device) (413).
Subsequently, a scan is performed (414), an Authentication is performed (415), an Association is performed (416), and a 4-way Handshake is performed (417).
In this way, when the connection is established, the control unit of the information processing device 200 uses the setting information used by each information processing device (for example, the information processing device (subordinate terminal) connected to the information processing device 200). Generate a list of (setting information list). This setting information list is a list composed of a combination of each detection threshold value of the physical header used by each information processing device and the application level (application condition) of the physical header. This setting information list will be described in detail with reference to FIG.
Further, in the embodiment of the present technology, the set of the detection threshold value of the physical header and the application level of the physical header is referred to as a physical header parameter.
The information processing device 200 updates the contents of the information already created among the information included in the setting information list.
[Example of contents of setting information list]
FIG. 9 is a diagram schematically showing an example of the contents of the setting information list 161 stored in the memory of the information processing apparatus 200 (corresponding to the memory 160 shown in FIG. 5) according to the first embodiment of the present technology. ..
The index 162, the detection threshold value 163, and the application level 164 are stored in the setting information list 161 in association with each other.
The index 162 stores values (0, 1) indicating far / near.
The detection threshold value 163 stores the detection threshold value of the physical header determined by the physical header parameter determination process. The physical header parameter determination process is shown in FIG.
The application level 164 stores the application level of the physical header determined by the physical header parameter determination process.
[Operation example of physical header parameter determination processing]
FIG. 10 is a flowchart showing an example of the processing procedure of the physical header parameter determination processing by the information processing apparatus 200 in the first embodiment of the present technology.
First, the control unit of the information processing apparatus 200 tentatively determines the physical header parameters used by the subordinate terminal in the own BSS (Basic Service Set) and the own device. The control unit of the information processing apparatus 200 tentatively determines the detection threshold PD_near of the short-distance physical header and the detection threshold PD_far of the long-distance physical header.
Here, regarding the detection threshold PD_far of the physical header for a long distance, since there is no physical header of the applicable condition lower than that, the detection threshold is temporarily set to the set value PD_default for the legacy device.
This Legacy device setting value PD_default is a value that represents the reference level for preamble detection used by the Legacy device, and the IEEE802.11 standard refers to a value of -82 dBm per 20 MHz bandwidth as a guideline value. .. Further, a value other than -82 dBm may be used as the set value PD_default for the legacy device.
Subsequently, the control unit of the information processing apparatus 200 determines the application levels L_near and L_far of each physical header based on the detection threshold PD_near of the short-distance physical header and the detection threshold PD_far of the long-distance physical header. Specifically, the control unit of the information processing apparatus 200 determines the application levels L_near and L_far of each physical header so as to satisfy the following equations 1 and 2. Here, Equations 1 and 2 are descriptions assuming a logarithmic (dB) calculation. L_near> PD_near + O_near ... Equation 1 L_far = - ... Equation 2
Here, the application levels L_near and L_far of each physical header are thresholds for selecting the physical header to be used (physical header for long distance, physical header for short distance) based on the communication quality with the destination device. For example, when the information processing apparatus 100 transmits, the application levels L_near and L_far of each physical header are used as threshold values when selecting the physical header to be used based on the communication quality with the destination apparatus.
Further, in Equation 1, O_near is the amount of margin offset with respect to the preamble detection error due to the fluctuation of the reception level. For example, a value of about 10 to 20 dBm can be used as O_near. A value other than 10 to 20 dBm may be used as O_near.
Also, as shown in Equation 2, L_far is set to infinitesimal because there is no physical header for the applicable conditions below this.
Subsequently, the control unit of the information processing apparatus 200 performs packet monitoring (step S701). Then, the control unit of the information processing apparatus 200 acquires each information regarding the communication quality with the information processing apparatus under each subordinate in the own BSS and the communication quality of the packet from another BSS (OBSS) (step S701).
Here, an example of using the correlated output strength of the PLCP preamble as an index of communication quality is shown. This correlated output strength shall indicate the absolute level obtained by multiplying the correlated output by the received signal strength (RSSI) (RSSI), not the correlated output itself in which the power is normalized. That is, the correlation output intensity means the correlator output corrected in terms of antenna input. Further, when the reception history in a relatively short time exists, the record of the correlation output intensity at that time may be diverted. In addition, the detection threshold value may be temporarily lowered so that samples can be collected more reliably during monitoring.
Here, the relationship between RSSI and the correlation output intensity COL (Correlator Output Level) can be simply shown by the following equation. Correlation output intensity COL = RSSI × Normalized correlator output
Figure 11 shows an example of the configuration of the correlator.
[Example of correlator configuration]
FIG. 11 is a diagram showing a configuration example of a correlator provided in the information processing apparatus 200 according to the first embodiment of the present technology. Note that FIG. 11 shows a configuration example of a general correlator that serves as a reference. Here, the operator (*) shown in FIG. 11 indicates a complex conjugate operation.
Here, the correlator generally has two types of configurations depending on the characteristics of the preamble. For example, there are two configurations, an autocorrelation detection configuration that generally detects a signal having a certain periodicity and a cross-correlation detection configuration that detects a correlation with a fixed pattern. A of FIG. 11 shows a configuration example of autocorrelation detection, and b of FIG. 11 shows a configuration example of cross-correlation detection.
Further, in FIG. 10, the control unit of the information processing apparatus 200 classifies the communication quality information according to the Link Strength Category field in the physical header used when the information is received (step S702).
For example, the control unit of the information processing apparatus 200 sets the minimum correlation output strength to COL_self_far among packets whose BSS identifier (BSSID) is its own BSS, whose physical header is a long-distance physical header, and which is not an error. ..
Further, the control unit of the information processing apparatus 200 sets the maximum correlation output strength to COL_other_near among packets whose BSS identifier (BSSID) is another BSS, whose physical header is a short-range physical header, and which is not an error. ..
Further, in the control unit of the information processing apparatus 200, the maximum correlation output strength is set to COL_other_far among the packets whose BSS identifier (BSSID) is another BSS, whose physical header is a long-distance physical header, and which is not an error. .. COL that does not have a packet sample with the applicable conditions shall be replaced with PD_default.
Subsequently, the control unit of the information processing apparatus 200 determines the detection threshold PD_near of the short-distance physical header and the detection threshold PD_far of the long-distance physical header (step S703). That is, the control unit of the information processing apparatus 200 establishes the relationship of the following equations 3 to 5 between the tentatively determined detection threshold value PD_near of the short-distance physical header and the detection threshold value PD_far of the long-distance physical header. (Step S703). PD_near> COL_other_near ... Equation 3 PD_far <COL_self_far ... Equation 4 PD_far> COL_other_far ... Equation 5
If there is no PD_far that can achieve both Equation 4 and Equation 5, PD_far is determined with priority given to the establishment of Equation 4.
Further, when the control unit of the information processing apparatus 200 determines (updates) those detection threshold values, the control unit corrects the application levels L_near and L_far of each physical header based on the above equations 1 and 2. (Step S703).
In this way, the detection threshold PD_near of the short-distance physical header, the detection threshold PD_far of the long-distance physical header, and the application levels L_near and L_far of each physical header are determined. The control unit of the information processing apparatus 200 stores each value determined in this way in the setting information list 161 (shown in FIG. 9), and subsequently refers to and uses the value. Specifically, the control unit of the information processing apparatus 200 stores PD_far in the detection threshold value 163 corresponding to the index 162 0 and stores L_far in the application level 164 corresponding to the index 162 0. Further, the control unit of the information processing apparatus 200 stores PD_near in the detection threshold value 163 corresponding to the index 162 1 and stores L_near in the application level 164 corresponding to the index 162 1.
Here, the above-mentioned monitoring of the surrounding packets and the update of each setting value may be performed periodically or irregularly. For example, it may be performed periodically at regular intervals, or it may be performed every time a new subordinate terminal is connected.
[Example of carrier sense detection range]
12 and 13 are diagrams showing a system configuration example of the communication system 10 according to the first embodiment of the present technology.
In FIGS. 12 and 13, the carrier sense detection range of each information processing device set based on the short-distance physical header detection threshold PD_near and the long-distance physical header detection threshold PD_far determined by the information processing device 200. An example is shown.
Further, in FIG. 12, the carrier sense detection ranges 31 to 34 of the information processing devices 100 and 102 are schematically shown by dotted circles. Further, in FIG. 13, the carrier sense detection ranges 41 to 44 of the information processing devices 200 and 201 are schematically shown by dotted circles.
Specifically, in FIG. 12, the carrier sense detection range 31 indicates the carrier sense detection range of the information processing apparatus 100 set based on the detection threshold PD_far of the physical header for a long distance. Further, the carrier sense detection range 33 indicates the carrier sense detection range of the information processing apparatus 100 set based on the detection threshold PD_near of the short-distance physical header.
Further, in FIG. 12, the carrier sense detection range 32 indicates the carrier sense detection range of the information processing apparatus 102 set based on the detection threshold PD_far of the physical header for a long distance. Further, the carrier sense detection range 34 indicates the carrier sense detection range of the information processing apparatus 102 set based on the detection threshold PD_near of the short-distance physical header.
Further, in FIG. 13, the carrier sense detection range 41 indicates the carrier sense detection range of the information processing apparatus 200 set based on the detection threshold PD_far of the physical header for a long distance. Further, the carrier sense detection range 43 indicates the carrier sense detection range of the information processing apparatus 200 set based on the detection threshold PD_near of the short-distance physical header.
Further, in FIG. 13, the carrier sense detection range 42 shows the carrier sense detection range of the information processing apparatus 201 set based on the detection threshold PD_far of the physical header for a long distance. Further, the carrier sense detection range 44 indicates the carrier sense detection range of the information processing apparatus 201 set based on the detection threshold PD_near of the short-distance physical header.
In the above, an example of two-value classification of short-distance and long-distance is shown, but three-value or more (N value) may be classified. For example, the detection thresholds of each physical header are PD_0, PD_1, ..., PD_N in order from the longest distance, and the application levels of each PLCP are L_0, L_1, ..., L_N. Further, the detection threshold value of each physical header and the offset amount between the application levels of each physical header are O_0, O_1, ..., O_N. In this case, each value is determined so as to satisfy the following relational expression (Equation 6 to 9). Here, Equations 6 to 9 are descriptions assuming calculation in logarithm (dB). PD_n> COL_other_n ... Equation 6 However, n = 0 to N. PD_0 <COL_self_0 ... Equation 7 L_n> PD_n + O_n ... Equation 8 However, n = 1 to N. L_0 =- ... Equation 9
Even in the case of classification of three or more values, if PD_0 that can achieve both Equation 6 and Equation 7 does not exist, PD_0 is determined with priority given to the establishment of Equation 7.
[Beacon frame format example]
FIG. 14 is a diagram showing an example of a beacon frame format exchanged between the devices constituting the communication system 10 according to the first embodiment of the present technology. Here, an example of a beacon frame transmitted from the information processing device 200 to another information processing device is shown.
Figure 14 shows an example of adding a new element called Multi Detect Parameter 311 to Payload 310. Then, in the "Multi Detect Parameter" 311 and the "PLCP Header Index" 313 and 316, the index (0/1) indicating far / near is stored. Further, the detection threshold PD_far of the physical header for long distance and the detection threshold PD_near of the physical header for short distance are stored in "Preamble Detection Threshold" 314 and 317. In addition, the application level of each physical header is stored in "Apply Level" 315 and 318.
In addition, each combination of "PLCP Header Index", "Preamble Detection Threshold", and "Apply Level" is provided only for the generated combination. For example, as shown in FIG. 9, it is assumed that two sets of information (two sets of indexes 162 0 and 1) are stored in the setting information list 161. In this case, only two combinations of "PLCP Header Index", "Preamble Detection Threshold", and "Apply Level" are provided.
Specifically, the control unit of the information processing apparatus 200 stores each content of the setting information list 161 shown in FIG. 9 in the beacon frame and transmits the information. That is, the control unit of the information processing apparatus 200 stores each information stored in association with the index 162 0 in the first combination (PLCP Header Index 313 to Apply Level 315). Further, the control unit of the information processing apparatus 200 stores each information stored in association with the index 162 1 in the following combinations (PLCP Header Index 316 to Apply Level 318).
Then, the control unit of the information processing apparatus 200 transmits a beacon in which each information shown in the Multi Detect Parameter 311 is stored to the surrounding information processing apparatus to notify the information. That is, the control unit of the information processing apparatus 200 has information on packet detection conditions (for example, packet detection threshold value (detection threshold value 163 shown in FIG. 9), selection condition for selecting the packet detection threshold value (application level 164 shown in FIG. 9)). Is transmitted to surrounding information processing devices to notify the user. Further, the selection condition can be grasped as a selection condition for selecting one from a plurality of physical header candidates and a selection condition of the physical header corresponding to each packet detection condition.
[Communication example of physical header parameter sharing process]
FIG. 15 is a sequence chart showing an example of physical header parameter sharing processing between the devices constituting the communication system 10 according to the first embodiment of the present technology.
FIG. 15 shows an example of sharing processing in which the control unit 150 of the information processing device 100 receives the beacon transmitted from the information processing device 200 and shares the physical header parameters. The same applies to the case where another information processing device receives the beacon transmitted from the information processing device 200. For example, the control unit of the information processing device 200 can notify the subordinate terminal of the physical header parameter by using the beacon frame shown in FIG.
First, the control unit of the information processing apparatus 200 stores a set of the detection threshold value of each physical header, the application level of each physical header, and the index of each physical header in the beacon (421). Then, the control unit of the information processing apparatus 200 transmits the beacon to the information processing apparatus under its control (422, 423).
When the control unit 150 of the information processing device 100 receives a beacon from the control unit of the information processing device 200 (423), the control unit 150 contains the contents of the Multi Detect Parameter 311 (shown in FIG. 14) included in the beacon. Get and hold (424).
Further, when the content of the "Multi Detect Parameter" 311 included in the beacon following the control unit 150 of the information processing apparatus 100 changes, the control unit 150 adopts and holds the new information after the change. That is, the old information is updated.
If the control unit 150 of the information processing device 100 has already acquired and holds the contents of the "Multi Detect Parameter" 311, the control unit 150 updates the held contents based on the newly received beacon. (424).
Although FIG. 15 shows an example in which the control unit of the information processing device 200 notifies each information processing device of the physical header parameter by a beacon, the physical header parameter may be notified by a beacon other than the beacon. For example, the control unit of the information processing device 200 may notify the subordinate terminal in a unicast data frame or a management frame by using a judgment by the own device or an information acquisition request from the subordinate terminal as a trigger. .. In that case, the control unit 150 of the information processing apparatus 100 similarly acquires and holds the contents of the Multi Detect Parameter included in the unicast frame.
[Operation example of physical header determination process]
FIG. 16 is a flowchart showing an example of a processing procedure of the physical header used determination process (selection process of the physical header for transmission) by the information processing apparatus 100 in the first embodiment of the present technology.
First, the control unit 150 of the information processing device 100 monitors received packets from a destination connected to the own device and acquires RSSI for each destination (step S711). The RSSI (monitor result) obtained in this way is called RSSI_peer.
When the measured value of the received packet from the destination connected to the own device is held, the control unit 150 of the information processing device 100 reads the measured value and acquires the RSSI for each destination. May be (step S711).
Here, in the case of an information processing device (for example, information processing device 100) connected to a master station (for example, information processing device 200), the destination is basically only the master station. In this case, the reception level of the beacon in the past may be used as the monitor result.
Subsequently, the control unit 150 of the information processing device 100 compares the acquired RSSI_peer with the application level L_near of the physical header, and determines the index of the physical header used by the own device for transmission based on the comparison result. (Step S712). The application level L_near of the physical header is included in the beacon transmitted from the information processing apparatus 200.
For example, when the acquired RSSI_peer exceeds the application level L_near of the physical header, the control unit 150 of the information processing device 100 sets the index of the physical header used by the own device for transmission to 1 (for short distance). Determine (step S712). On the other hand, when the acquired RSSI_peer is equal to or lower than the application level L_near of the physical header, the control unit 150 of the information processing device 100 determines that the index of the physical header used by the own device for transmission is 0 (for long distance). (Step S712).
Also, if the index of the physical header used by the own device for transmission has already been determined and a new index is determined, the already determined index is updated to the new index ( Step S712).
In addition, in FIG. 16, an example in which the physical header used is determined based on the classification of two values of short distance and long distance is shown, but the physical header used is determined based on the classification of three values or more (N value). It may be. For example, the application levels of each PLCP are L_0, L_1, ..., L_N in order from the long-distance one. In this case, n that satisfies the following relational expression (Equation 10) is selected as the index of the physical header used for transmission. Here, Equation 10 is a description assuming a logarithmic (dB) calculation. L_n RSSI_peer <L_n + 1 ... Equation 10 However, n = 0 to N.
Note that FIG. 16 has described an example of operation on the slave station side in the case of uplink transmission from the slave station side to the master station side, but in the case of downlink transmission, the same operation should be performed on the master station side. It may be.
Further, although FIG. 16 shows an example in which RSSI is used, the correlation output intensity COL may be used instead of RSSI.
[Operation example of transmission / reception processing]
FIG. 17 is a flowchart showing an example of a processing procedure of transmission / reception processing by the information processing apparatus 100 according to the first embodiment of the present technology. Although the information processing device 100 will be described with reference to FIG. 17, the same can be applied to other information processing devices (for example, the information processing device 200). That is, this transmission / reception processing is the same on both the master station side and the terminal side.
The control unit 150 of the information processing apparatus 100 performs packet detection determination processing at times other than during transmission and reception (step S730). This packet detection determination process will be described in detail with reference to FIG.
Subsequently, the control unit 150 of the information processing apparatus 100 determines whether or not the determination result by the packet detection determination process is detection (step S721). When the determination result by the packet detection determination process is "detection" (step S721), the control unit 150 of the information processing apparatus 100 performs the reception process of continuing the reception as it is (step S722). Then, the control unit 150 of the information processing device 100 returns to the standby state after the reception is completed. If the received packet is addressed to its own device and an immediate response is requested, the control unit 150 of the information processing device 100 adds a physical header having the same "Link Strength Category" field as the target packet. And send. That is, the part in which the information regarding the detection threshold value in the SIGNAL field is stored is the same, and the information determined by the own device is stored in the other parts (for example, MCS (Modulation and Coding Scheme), length).
If the determination result by the packet detection determination process is not "detection" (step S721), the control unit 150 of the information processing apparatus 100 determines whether or not the determination result by the packet detection determination process is "non-detection". (Step S723). When the determination result by the packet detection determination process is "non-detection" (step S723), the control unit 150 of the information processing apparatus 100 determines whether or not there is a packet to be transmitted (step S724).
When there is a packet to be transmitted, the control unit 150 of the information processing apparatus 100 determines that the non-detection state is the frame interval defined by the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) procedure (IFS (Inter)). Frame Space)) and determine if it has continued for more than the backoff time (step S725).
When the non-detection determination state continues for the IFS and backoff time or longer (step S725), the control unit 150 of the information processing apparatus 100 can perform transmission, and therefore performs transmission processing (step S726). ). In this transmission process, the control unit 150 of the information processing apparatus 100 uses, for example, the physical header in the PPDU format shown in FIG. 7 based on the index of the physical header determined by the physical header determination process for transmission shown in FIG. Use to send.
Specifically, the control unit 150 of the information processing apparatus 100 stores 1 in the "Link Strength Category field" when 1 (for short distance) is determined as an index by the physical header determination process for transmission. Send (step S726). On the other hand, when the control unit 150 of the information processing apparatus 100 determines 0 (for a long distance) as an index by the physical header determination process for transmission, the control unit 150 stores 0 in the "Link Strength Category field" and transmits the information ( Step S726).
Further, the control unit 150 of the information processing device 100 can receive, for example, the modulation used for the data unit with a high probability by the destination device according to the detection threshold value corresponding to the determined physical header. Select a coding method and use it to send. Further, the control unit 150 of the information processing apparatus 100 has, for example, a modulation and communication path coding method (MCS (Modulation)) in which the destination apparatus can receive with high probability according to the detection threshold value corresponding to the determined physical header. and Coding Scheme)) may be selected for transmission. Then, when there are no more packets to be transmitted, the process returns to the standby state.
When the judgment result by the packet detection judgment processing is not "non-detection" (when the judgment result is "energy only detection") (step S723), the control unit 150 of the information processing apparatus 100 is basically busy with the wireless state. Treat it as a state and suppress transmission from its own device (step S727). However, only when a packet addressed to the own device is received and a response immediately after the reception is requested (step S728), the control unit 150 of the information processing device 100 transmits the response packet (step S729).
FIG. 18 is a flowchart showing a packet detection determination process (processing procedure in step S730 shown in FIG. 17) among transmission / reception processes by the information processing apparatus 100 according to the first embodiment of the present technology.
First, the control unit 150 of the information processing apparatus 100 measures RSSI for the signal input via the antenna 141, and holds the RSSI obtained by the measurement (step S731).
Subsequently, the control unit 150 of the information processing apparatus 100 performs the correlation calculation of the Preamble pattern and obtains the correlator output (step S732). This correlator output means the above-mentioned correlation output intensity COL. That is, the correlator output is not the normalized correlator output level, but the correlator output converted to reflect the received power.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the value of the correlator output with the temporary detection threshold value, and determines whether or not the value of the correlator output exceeds the temporary detection threshold value (step S733). Here, the provisional detection is a detection for determining whether or not to read the SINGAL field prior to the detection determination. Further, the provisional detection threshold value shall be a value equal to or less than both PD_near and PD_far described above. The provisional detection threshold may be set to PD_default as described above.
When the value of the correlator output exceeds the provisional detection threshold value (step S733), the control unit 150 of the information processing apparatus 100 determines that it is in the provisional detection state (step S734). Subsequently, the control unit 150 of the information processing apparatus 100 reads out the "Link Strength Category field" in the subsequent SIGNAL field in the physical header. As described above, the "Link Strength Category field" stores information indicating the detection threshold to be applied.
Here, the control unit 150 of the information processing apparatus 100 holds the contents of the Preamble Detection Threshold shared in the physical header parameter sharing process shown in FIG. The control unit 150 of the information processing apparatus 100 determines the detection threshold value (application detection threshold value) to be applied based on the content of the Preamble Detection Threshold and the content of the Link Strength Category field (step S735). ..
For example, when Link Strength Category = 0, the control unit 150 of the information processing apparatus 100 determines the application detection threshold value as PD_far. On the other hand, when Link Strength Category = 1, the control unit 150 of the information processing apparatus 100 determines the application detection threshold value as PD_near. Then, the control unit 150 of the information processing apparatus 100 uses the determined application detection threshold value (PD_far or PD_near) when performing transmission / reception processing.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the measured and held RSSI with the determined application detection threshold value, and whether the RSSI exceeds the application detection threshold value (PD_far or PD_near). Determine if not (step S736). Then, when the RSSI exceeds the application detection threshold value (step S736), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result as detection (step S737).
Here, the packet detection determination result may be set to "detection" only when other conditions are satisfied. For example, an error detection code including the "Link Strength Category field" may be provided in the remaining Reserved field in the SIGNAL field. Then, the condition that the validity of the content of the "Link Strength Category field" is confirmed by the error detection code including the "Link Strength Category field" may be an additional determination condition.
Here, the error detection code including the "Link Strength Category field" may be inserted into the remaining Reserved field in the Service field. Then, the condition that the validity of the content of the "Link Strength Category field" is confirmed by the error detection code including the "Link Strength Category field" may be an additional determination condition.
If the RSSI is equal to or less than the application detection threshold value (step S736), the control unit 150 of the information processing apparatus 100 cancels reception (step S738). Subsequently, the control unit 150 of the information processing apparatus 100 compares the RSSI with the energy detection threshold value ED, and determines whether or not the RSSI exceeds the energy detection threshold value ED (step S739). Here, the energy detection threshold ED can be, for example, -62 dBm per 20 MHz bandwidth.
When the RSSI exceeds the energy detection threshold value ED (step S739), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to energy only detection (step S740).
When the RSSI is equal to or less than the energy detection threshold value ED (step S739), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to non-detection (step S741).
In each of the above-mentioned comparison processes, the above-mentioned correlation output intensity COL may be used instead of RSSI.
According to the first embodiment of the present technology, the master station and the slave station can transmit and receive at the same time (or substantially simultaneously), and can enable the reuse of radio resources.
Further, for example, when the slave station (for example, the information processing device 100) transmits to the master station (for example, the information processing device 200), the slave station on the OBSS side (for example, information processing) is prior to the transmission. It is assumed that the device 102) starts transmission.
Even in this case, the control unit 150 of the information processing apparatus 100 uses the detection threshold PD_near or PD_far of the physical header to perform the detection determination according to the physical header. For example, as shown in FIG. 12, carrier sense detection ranges 31 and 33 of the information processing apparatus 100 are set. As a result, even if the information processing device 102 is transmitting the signal, the control unit 150 of the information processing device 100 can treat the signal as non-detection and can transmit the signal to the information processing device 200.
However, even if the information processing device 100 can perform transmission, if the information processing device 200 receives the transmission of the information processing device 102 first, the information processing device 200 transmits from the information processing device 100. I can't receive it. Therefore, in the first embodiment of the present technology, the carrier sense detection ranges 41 and 43 of the information processing apparatus 200 are set as shown in FIG. As a result, since the information processing device 200 does not detect the transmission of the information processing device 102, it can wait for the reception from the information processing device 100.
Here, if the information processing device 200 uniformly raises the detection threshold value, the packet from the information processing device 101 may not be detected. Therefore, since the transmission from the information processing device 101 (legacy device) located at a long distance is treated as a long-distance physical header and detected, the detection threshold value for a long distance is applied. As a result, the information processing apparatus 200 can receive reception from each information processing apparatus without delay.
Here, when the IEEE802.11 standard is assumed, the detection threshold value of the L-STF unit can be used as the detection threshold value in the first embodiment of the present technology. However, instead of the detection threshold value of the L-STF part, the detection threshold value of the L-LTF part may be used, or the detection threshold value common to both the L-STF part and the L-LTF part may be used. Good. Further, the detection thresholds of the L-STF part and the L-LTF part may be changed independently, and may be extended so that both are specified as physical header parameters.
Further, the physical header parameters of the own device may be determined based on the Capability that can be used by other information processing devices.
<2. Second Embodiment> In the first embodiment of the present technology, the packet detection determination result is "energy only detection", and even if transmission suppression is set, the transmission suppression is temporarily suppressed. An example of canceling is shown. That is, even if transmission suppression is set, the transmission suppression is temporarily released because the response packet is transmitted only when a packet addressed to the own device is received and a response immediately after the reception is requested. An example is shown.
In the second embodiment of the present technology, an example is shown in which when the packet detection determination result is "energy only detection" and transmission suppression is set, no transmission is performed. The configuration of the information processing device according to the second embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
In addition, each process and each format in the second embodiment of the present technology also has some parts in common with the first embodiment of the present technology. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
[Operation example of transmission / reception processing]
FIG. 19 is a flowchart showing an example of a processing procedure of transmission / reception processing by the information processing apparatus 100 in the second embodiment of the present technology. Note that FIG. 19 is a modification of a part of the transmission / reception processing shown in FIG. Therefore, the parts common to the transmission / reception processing shown in FIG. 17 are designated by the same reference numerals as those in FIG. 17, and some of these descriptions will be omitted.
When the determination result by the packet detection determination process is "only energy detected" (step S723), the control unit 150 of the information processing device 100 basically treats the wireless state as a busy state and suppresses transmission from its own device. (Step S727). When the wireless state is treated as a busy state in this way, in the second embodiment of the present technology, all transmissions are suppressed.
As described above, in the second embodiment of the present technology, when the determination result by the packet detection determination process is "energy only detection", all transmission is suppressed. As a result, the safety of the operation of the transmission / reception processing can be further enhanced.
<3. Third Embodiment> In the first embodiment of the present technology, an example in which the Link Strength Category field is provided in the SIGNAL field of the IEEE 802.11 standard is shown.
In the third embodiment of the present technology, an example in which the Link Strength Category field is provided in the Service field of the IEEE 802.11 standard is shown. The configuration of the information processing device according to the third embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
In addition, each process and each format in the third embodiment of the present technology also has some parts in common with the first embodiment of the present technology. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
[PPDU format example]
FIG. 20 is a diagram showing an example of a PPDU format exchanged between the devices constituting the communication system 10 according to the third embodiment of the present technology.
Here, the example shown in FIG. 20 is the same as the example shown in FIG. 7 except that the Link Strength Category field is provided in the Service field instead of being provided in the SIGNAL field. Therefore, the parts common to FIG. 7 are designated by the same reference numerals as those in FIG. 7, and some of these explanations will be omitted.
The PPDU is composed of Preamble301, SIGNAL307, Extension303, Service308, MPDU305, and FCS306.
Here, in the third embodiment of the present technology, a "Link Strength Category field" is newly prepared as a part of the field of Service308 of the physical header. That is, a new "Link Strength Category field" is provided in the part of the physical header that is treated as Reserved in Service 308. Then, each information processing device (other than the legacy device) changes the "Link Strength Category field" according to the quality of the link with the destination at the time of transmission.
As described above, in the third embodiment of the present technology, the "Link Strength Category field" is provided in the portion of Service 308 that is treated as Reserved. As a result, as in the first embodiment of the present technology, the specific function can be realized without hindering the reception of the legacy device.
[Operation example of transmission / reception processing]
In the transmission / reception processing shown in FIG. 18 (step S735), the "SIGNAL field" is replaced with the "Service field", and the same processing as the transmission / reception processing shown in FIGS. 17 and 18 is performed to perform the third implementation of the present technology. The form of can be realized.
Here, the error detection code including the "Link Strength Category field" may be inserted into the remaining Reserved field in the Service field. Then, the condition that the validity of the content of the "Link Strength Category field" is confirmed by the error detection code including the "Link Strength Category field" may be an additional determination condition.
As described above, in the third embodiment of the present technology, the Link Strength Category field is provided in the Service field of the IEEE 802.11 standard. As a result, more information can be stored as compared with the first embodiment of the present technology. For example, even when the PLCP mode is set to multiple values, the information can be stored appropriately.
<4. Fourth Embodiment> In the first to third embodiments of the present technology, an example in which the detection threshold value of PLCP is changed based on the contents of the fields of the physical header is shown.
In the fourth embodiment of the present technology, an example is shown in which a plurality of preamble sequences having different detection thresholds are used on the transmitting side, and the receiving side switches the preamble correlation detector applied by RSSI. As a result, the receiving side can receive only the desired packet. The configuration of the information processing device according to the fourth embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
In addition, each process and each format in the fourth embodiment of the present technology also has some parts in common with the first embodiment of the present technology. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
[PPDU format example]
FIG. 21 is a diagram showing an example of the format of PPDU exchanged between the devices constituting the communication system 10 according to the fourth embodiment of the present technology.
Here, the example shown in FIG. 21 is the same as the example shown in FIG. 7 except that a plurality of Preamble series are defined instead of providing the Link Strength Category field in the SIGNAL field. Therefore, the parts common to FIG. 7 are designated by the same reference numerals as those in FIG. 7, and some of these explanations will be omitted.
The PPDU is composed of Preamble311, SIGNAL312, Extension303, Service304, MPDU305, and FCS306.
Here, in the fourth embodiment of the present technology, a plurality of series of Preamble311 are defined. For example, as shown in a of FIG. 21, a series called "Preamble # 1" is defined in Preamble311. Further, as shown in b of FIG. 21, a series called "Preamble # 0" is defined. Then, each information processing device (other than the legacy device) changes the sequence to be used according to the quality of the link with the destination at the time of transmission. Although FIG. 21 shows an example in which two types of Preambles are prepared, three or more types of Preambles may be prepared.
Further, in the fourth embodiment of the present technology, the physical header using the series "Preamble # 0" in Preamble311 is referred to as the "physical header for long distance". Further, a physical header using the series "Preamble # 1" in Preamble311 is referred to as a "short-distance physical header". In addition, each Preamble series is generated by different rules and has low cross-correlation. The Preamble series # 0 is the same series as the Preamble used by the Legacy device.
Each information processing device (other than the legacy device) that receives the packet having such a physical header changes the correlator to be applied (and the threshold value for determining detection) according to the magnitude of the RSSI of the signal.
Here, when assuming the IEEE802.11 standard, "another Preamble" means that at least one of L-STF and L-LTF is different.
[Operation example of transmission / reception processing]
FIG. 22 is a flowchart showing a packet detection determination process (processing procedure in step S730 shown in FIG. 17) among transmission / reception processes by the information processing apparatus 100 according to the fourth embodiment of the present technology.
First, the control unit 150 of the information processing apparatus 100 measures RSSI for the signal input via the antenna 141, and holds the RSSI obtained by the measurement (step S751).
Subsequently, the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the applied level (L_far and L_near) of each physical header held, and determines the index of the physical header applied to the detection. (Step S752). For example, the index of the physical header applied to the detection can be determined in the same manner as the selection method of selecting the physical header for transmission of the own device.
For example, the control unit 150 of the information processing device 100 compares the measured RSSI with the value of L_near, and if the measured RSSI exceeds L_near, the physical header used for the correlation detection of the own device. Determine the index of 1 (for short distance). Further, when the measured RSSI is L_near or less, the control unit 150 of the information processing apparatus 100 determines the index of the physical header used for the correlation detection of the own apparatus to 0 (for long distance).
This determination procedure is based on the premise that there is no difference in transmission power between the slave station and the master station. However, even if there is a difference in transmission power between the slave station and the master station, if the information on the difference in transmission power is retained in advance, it is appropriate based on the information on the difference in transmission power held. It can be determined after the correction is applied.
Subsequently, the control unit 150 of the information processing apparatus 100 performs the correlation calculation using the correlator corresponding to the preamble series generated by the different rules as described above for the physical header of the determined index (step S753). .. Here, the correlator output means the correlation output intensity COL, as in the first embodiment of the present technology. That is, the correlator output is not the normalized correlator output level, but the correlator output converted to reflect the received power.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the correlator output of the selected correlator with the detection threshold value of the physical header at the determined index, and the value of the correlator output determines the detection threshold value. Determine if it is exceeded (step S754).
When the value of the correlator output exceeds the detection threshold value (step S754), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result as detection (step S755).
When the value of the correlator output is equal to or less than the detection threshold value (step S754), the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the energy detection threshold value ED (step S756). .. Then, the control unit 150 of the information processing apparatus 100 determines whether or not the RSSI exceeds the energy detection threshold value ED (step S756).
When the RSSI exceeds the energy detection threshold value ED (step S756), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to energy only detection (step S757).
When the RSSI is equal to or less than the energy detection threshold value ED (step S756), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to non-detection (step S758).
Here, when the IEEE802.11 standard is assumed, the detection threshold value of the L-STF unit can be used as the detection threshold value in the fourth embodiment of the present technology. However, instead of the detection threshold value of the L-STF part, the detection threshold value of the L-LTF part may be used, or the detection threshold value common to both the L-STF part and the L-LTF part may be used. Good. Further, the detection thresholds of the L-STF part and the L-LTF part may be changed independently, and may be extended so that both are specified as physical header parameters.
<5. Fifth Embodiment> The fifth embodiment of the present technology is a modification of the fourth embodiment of the present technology, and the selection of the physical header used by the subordinate information processing device is the parent. An example performed by the station side is shown. Further, the receiving side shows an example in which the correlators of the candidate preamble series are always operated in parallel.
The configuration of the information processing device according to the fifth embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first to fourth embodiments of the present technology are designated by the same reference numerals as those of the first to fourth embodiments of the present technology, and some of these explanations are omitted. To do.
In addition, each process and each format in the fifth embodiment of the present technology also has some parts in common with the first to fourth embodiments of the present technology. Therefore, the parts common to the first to fourth embodiments of the present technology are designated by the same reference numerals as those of the first to fourth embodiments of the present technology, and some of these explanations are omitted. To do.
[Beacon frame format example]
FIG. 23 is a diagram showing an example of a beacon frame format exchanged between the devices constituting the communication system 10 according to the fifth embodiment of the present technology. Since FIG. 23 is a modification of FIG. 14, the parts common to FIG. 14 are designated by the same reference numerals as those in FIG. 14, and a part of these explanations will be omitted.
FIG. 23 shows an example of newly adding an element called Multi Detect Assignment 321 together with Multi Detect Parameter 311 to Payload 320.
In the "Multi Detect Assignment" 321 and the "Association IDs" 323 and 325, information for identifying the subordinate information processing device is stored. Although FIG. 23 shows an example in which the Association ID is stored as the information for identifying the information processing device, other information that can identify the information processing device may be stored. For example, the MAC address may be stored.
In addition, the index (0 or 1) of the physical header used by the information processing device is stored in the "PLCP Header Index" 324 and 326. Then, these combinations are stored side by side for all the information processing devices (other than the Legacy device) under the control.
Then, the control unit of the information processing apparatus 200 transmits a beacon in which each information shown in the Multi Detect Parameter 311 and the Multi Detect Assignment 321 is stored to the surrounding information processing apparatus to notify the information.
[Communication example of physical header parameter sharing process]
FIG. 24 is a sequence chart showing an example of connection processing between the devices constituting the communication system 10 according to the fifth embodiment of the present technology.
Since FIG. 24 is a modification of FIG. 15, a part of the description of the parts common to FIG. 15 will be omitted. That is, FIG. 24 shows an example in which the physical header parameter itself is included in the beacon and transmitted, and the information for designating the physical header to be used by each subordinate information processing device is also included in the beacon and transmitted.
First, the control unit of the information processing apparatus 200 sets the combination of the detection threshold value of each physical header, the application level of each physical header, and the index of each physical header as the beacon "Multi Detect Parameter" 311 (shown in FIG. 23). Store in (431).
Further, the control unit of the information processing apparatus 200 stores a set of information for specifying the physical header used by each information processing apparatus under the information processing apparatus 200 in the beacon "Multi Detect Assignment" 321 (shown in FIG. 23) (432). ).
Here, the case of storing the contents of the "Multi Detect Assignment" field will be described. The control unit of the information processing device 200 stores only the corresponding Preamble series after confirming whether the Preamble series generation function specified by the Capability of each subordinate information processing device and the correlation detection function are supported. It shall be. Further, when selecting the physical header used by each subordinate information processing device corresponding to the specific function, the determination is made by using the information of the link quality between the master station and each subordinate slave station. For this purpose, the received packet from the destination connected to the own device is monitored (or the held measured value is read out), and the RSSI for each destination is acquired and used. In addition, instead of RSSI, the above-mentioned correlation output intensity COL may be used.
Subsequently, the control unit of the information processing apparatus 200 transmits the beacon to the information processing apparatus under its control (433, 434).
When the control unit 150 of the information processing device 100 receives the beacon from the information processing device 200 (434), the control unit 150 acquires and holds each content included in the beacon (435). That is, the control unit 150 of the information processing apparatus 100 acquires and holds the contents of the Multi Detect Parameter 311 and the Multi Detect Assignment 321 (shown in FIG. 23) included in the beacon (435).
Then, the control unit 150 of the information processing device 100 uses the corresponding physical header according to the index of the physical header designated by the master station (information processing device 200) in the beacon. That is, the control unit 150 of the information processing device 100 does not make an autonomous determination.
[Operation example of transmission / reception processing]
FIG. 25 is a flowchart showing a packet detection determination process (processing procedure in step S730 shown in FIG. 17) among transmission / reception processes by the information processing apparatus 100 according to the fifth embodiment of the present technology.
FIG. 25 shows an example in which each master station and each slave station corresponding to a specific function operate all the correlators of the PLCP Preamble supported by the own device in parallel.
First, the control unit 150 of the information processing apparatus 100 measures the RSSI for the signal input via the antenna 141, and holds the RSSI obtained by the measurement (step S761).
Subsequently, the control unit 150 of the information processing apparatus 100 inputs the input signal to each correlator and performs the correlation calculation (step S762). That is, the control unit 150 of the information processing apparatus 100 calculates the preamble correlation at the same time in each correlator (step S762).
Here, as each detection threshold value for determining detection based on each correlator output, each physical header detection threshold value designated by the master station is used in the physical header parameter sharing process. Further, the correlator output means the correlation output intensity COL as in the first embodiment of the present technology. That is, the correlator output is not the normalized correlator output level, but the correlator output converted to reflect the received power.
Subsequently, the control unit 150 of the information processing apparatus 100 determines whether or not the correlator output of any of the plurality of correlators exceeds the corresponding detection threshold value (step S763).
When the correlator output of any of the plurality of correlators exceeds the corresponding detection threshold value (step S763), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result as "detection". (Step S764).
Further, when all the correlator outputs of the plurality of correlators do not exceed the corresponding detection threshold values (step S763), the control unit 150 of the information processing apparatus 100 determines the measured RSSI and the energy detection threshold value. Compare with ED (step S765). Then, the control unit 150 of the information processing apparatus 100 determines whether or not the RSSI exceeds the energy detection threshold value ED (step S765).
When the RSSI exceeds the energy detection threshold value ED (step S765), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to energy only detection (step S766).
When the RSSI is equal to or less than the energy detection threshold value ED (step S765), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to non-detection (step S767).
<6. Sixth Embodiment> The sixth embodiment of the present technology is a modification of the fourth embodiment of the present technology, and the generation of a plurality of PLCP preambles for distinguishing is complete. An example is shown in which the original series is partially processed and generated instead of another series. This makes it possible to simplify the configuration of a plurality of correlators on the receiving side. In addition, by making the preamble series of the processing source a series of formats for legacy devices, it is possible to detect preambles even for information processing devices that do not support specific functions depending on the conditions, and it is possible to leave some backward compatibility. It becomes.
The configuration of the information processing device according to the sixth embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first to fourth embodiments of the present technology are designated by the same reference numerals as those of the first to fourth embodiments of the present technology, and some of these explanations are omitted. To do.
In addition, each process and each format in the sixth embodiment of the present technology also has some parts in common with the first to fourth embodiments of the present technology. Therefore, the parts common to the first to fourth embodiments of the present technology are designated by the same reference numerals as those of the first to fourth embodiments of the present technology, and some of these explanations are omitted. To do.
[PPDU format example]
The format of the PPDU in the sixth embodiment of the present technology is the same as the example shown in FIG.
That is, in the sixth embodiment of the present technology, a plurality of series of Preamble311 (shown in FIG. 21) are defined. For example, as shown in a of FIG. 21, a series called "Preamble # 1" is defined in Preamble311. Further, as shown in b of FIG. 21, a series called "Preamble # 0" is defined. Then, each information processing device (other than the legacy device) changes the sequence to be used according to the quality of the link with the destination at the time of transmission. Although FIG. 21 shows an example in which two types of Preambles are prepared, three or more types of Preambles may be prepared.
Further, in the sixth embodiment of the present technology, the physical header using the series "Preamble # 0" in Preamble311 is referred to as the "physical header for long distance". Further, a physical header using the series "Preamble # 1" in Preamble311 is referred to as a "short-distance physical header". The Preamble series # 0 is the same series as the Preamble used by the Legacy device.
Here, the method of generating the Preamble series other than Preamble # 0 is different between the sixth embodiment of the present technology and the fourth embodiment of the present technology. Specifically, in the sixth embodiment of the present technology, the series other than Preamble # 0 are based on Preamble # 0, and a processing process for reversing a part of the content is added. This processing is not limited to positive / negative inversion. For example, in the case of processing based on a certain series, another operation may be performed, such as thinning out a part of the content to make it 0.
Here, when assuming the IEEE802.11 standard, "another Preamble series" is a series in which the above-mentioned processing is added to at least one of L-STF and L-LTF to add a difference. It shall mean that.
Each information processing device (other than the legacy device) that has received the packet having such a physical header changes the correlation calculation (or packet detection determination threshold value) to be applied according to the magnitude of the RSSI of the signal.
[Operation example of physical header parameter determination processing]
The process of determining the physical header parameter in the sixth embodiment of the present technology is substantially the same as that in the fourth embodiment of the present technology. However, in the sixth embodiment of the present technology, the following extension may be added to the relational expression of the determination criterion of the detection threshold value of each physical header.
Equations 3 and 6 described above may be replaced by introducing a threshold offset in consideration of deterioration due to processing such as positive / negative inversion in the preamble series. For example, if the expected output value of the original correlator with respect to the input of the preamble with some positive and negative inversions is A times, change Equation 3 to Equation 11 below, and Equation 6 to the following. Can be changed as in Equation 12. Here, Equations 11 and 12 are descriptions assuming calculation in logarithm (dB). PD_near> COL_other_near + A_near ... Equation 11 PD_n> COL_other_n + A_n ... Equation 12 However, n = 0 to N.
[Operation example of transmission / reception processing]
FIG. 26 is a flowchart showing a packet detection determination process (processing procedure in step S730 shown in FIG. 17) in the transmission / reception processing by the information processing apparatus 100 according to the sixth embodiment of the present technology.
First, the control unit 150 of the information processing apparatus 100 measures RSSI for the signal input via the antenna 141, and holds the RSSI obtained by the measurement (step S771).
Subsequently, the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the applied level (L_far and L_near) of each physical header held, and determines the index of the physical header applied to the detection. (Step S772). For example, the index of the physical header applied to the detection can be determined in the same manner as the selection method of selecting the physical header for transmission of the own device.
For example, the control unit 150 of the information processing device 100 compares the measured RSSI with the value of L_near, and if the measured RSSI exceeds L_near, the physical header used for the correlation detection of the own device. Determine the index of 1 (for short distance). Further, when the measured RSSI is L_near or less, the control unit 150 of the information processing apparatus 100 determines the index of the physical header used for the correlation detection of the own apparatus to 0 (for long distance).
This determination procedure is based on the premise that there is no difference in transmission power between the slave station and the master station. However, even if there is a difference in transmission power between the slave station and the master station, if the information on the difference in transmission power is retained in advance, it is appropriate based on the information on the difference in transmission power held. It can be determined after the correction is applied.
Subsequently, the control unit 150 of the information processing apparatus 100 switches the internal calculation of the correlator corresponding to the preamble series of the physical header of the determined index to perform the correlation calculation (step S773). Here, the switching of the internal calculation is the same process as the process corresponding to the above-mentioned method of generating the PLCP Preamble section, "inverting a part of the content positively or negatively".
[Example of correlator configuration]
FIG. 27 is a diagram showing a configuration example of a correlator provided in the information processing apparatus 100 according to the sixth embodiment of the present technology. Note that a in FIG. 27 is a modification of a in FIG. 11, and b in FIG. 27 is a modification of b in FIG. Further, FIG. 27 shows a configuration example of a correlator that performs a code inversion operation based on the switching signal determined by RSSI. With this configuration, another preamble correlator can be easily configured.
For example, a large correlator output can be output by correctly matching the input PLCP Preamble with the correlator operation. However, if the operations are different, the correlator output will be small. Therefore, it is possible to select the packets to be detected by these. The definition of "correlator output" here is the same as the definition of "correlator output" described above.
For example, the operation of the correlator may be switched according to the preamble series of the physical header of the determined index, or the operation may not be changed and the detection threshold value may be switched. Moreover, you may switch both. As a result, it is possible to realize a process of selecting packets to be detected according to the situation. Note that FIG. 26 shows an example of switching between the two.
In FIG. 26, the control unit 150 of the information processing apparatus 100 switches between the correlator calculation and the detection threshold value corresponding to the preamble sequence of the physical header of the determined index (step S773). That is, the correlator operation and the detection threshold are set based on the determined index (step S773).
Subsequently, the control unit 150 of the information processing apparatus 100 compares the correlator output with the corresponding detection threshold value, and determines whether or not the value of the correlator output exceeds the detection threshold value (step S774).
When the value of the correlator output exceeds the detection threshold value (step S774), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result as detection (step S775).
When the value of the correlator output is equal to or less than the detection threshold value (step S774), the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the energy detection threshold value ED (step S776). .. Then, the control unit 150 of the information processing apparatus 100 determines whether or not the RSSI exceeds the energy detection threshold value ED (step S776).
When the RSSI exceeds the energy detection threshold value ED (step S776), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to energy only detection (step S777).
When the RSSI is equal to or less than the energy detection threshold value ED (step S776), the control unit 150 of the information processing apparatus 100 sets the packet detection determination result to non-detection (step S778).
<7. Seventh Embodiment> In the first to sixth embodiments of the present technology, in a star topology composed of a master station and subordinate slave stations, a communication example between the master station and the slave station is performed. Indicated. Further, in this communication example, the transmission destination of the subordinate slave station is limited to the master station. However, the first to sixth embodiments of the present technology can also be applied to direct communication between subordinate slave stations.
Therefore, in the seventh embodiment of the present technology, an example in which direct communication (for example, communication between the information processing devices 101 and 104 shown in FIG. 28) is performed between the subordinate slave stations is shown.
[Communication system configuration example]
FIG. 28 is a diagram showing a system configuration example of the communication system 50 according to the seventh embodiment of the present technology.
Note that FIG. 28 is a modification of FIG. 1, and is different from FIG. 1 in that the information processing device 104 is added. The configuration of the information processing device 104 is substantially the same as that of the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. In addition, the parts common to the first to sixth embodiments of the present technology are designated by the same reference numerals as those of the first to sixth embodiments of the present technology, and some of these explanations are omitted. ..
The communication system 50 is composed of information processing devices 100 to 104, information processing devices 200, and 201.
The information processing device 104 is an information processing device corresponding to the information processing devices 100 to 103, and is, for example, a portable information processing device having a wireless communication function.
As described above, in the seventh embodiment of the present technology, in the star topology composed of the master station and its subordinate slave stations, direct communication between the subordinate slave stations (for example, between the information processing devices 101 and 104) An example of performing communication) is shown.
[Communication example]
FIG. 29 is a sequence chart showing an example of communication processing between the devices constituting the communication system 50 according to the seventh embodiment of the present technology.
FIG. 29 shows an example of communication processing in the case of direct transmission between the information processing device 100 and the information processing device 104. The same applies to the relationships between other slave stations.
Here, the direct communication setup process basically conforms to the TDLS (Tunneling Direct Link Setup) function of the IEEE 802.11 standard. Further, in FIG. 29, it is assumed that the information processing devices 100 and 104 are already connected to the information processing device 200 and are performing the operation shown in the first embodiment of the present technology.
First, a direct link connection process is performed between the information processing devices 100, 104, and 200 (441). That is, each of the information processing devices 100 and 104 executes the direct link establishment protocol via the access point (information processing device 200) (441). As a result, the direct link search process can be performed without breaking the protocol. Since the direct link connection process is the same as the standard definition, detailed description here will be omitted.
Subsequently, the control unit of the information processing apparatus 200 performs the physical header parameter determination process (442). As described above, in the seventh embodiment of the present technology, the master station (information processing device 200) determines the physical header parameters used in the direct link between the subordinate slave stations. Therefore, the slave station does not perform the physical header parameter determination process. The physical header parameter determination process by the master station is the same as that of the first embodiment of the present technology.
Subsequently, the physical header parameter sharing process is performed among the information processing devices 100, 104, and 200 (443). As described above, in the seventh embodiment of the present technology, the master station (information processing device 200) also determines the physical header parameters used in the direct link between the subordinate slave stations. Therefore, the physical header parameter sharing process is not performed between the slave stations that perform the direct link. The physical header parameter sharing process between the master station and the slave station is the same as that of the first embodiment of the present technology.
Subsequently, each of the information processing devices 100 and 104 performs the physical header used determination process (444, 446). Here, the physical header for the other party during the direct link connection is determined according to the communication quality of the link with the other party, independently of the one for the master station. The criteria for this determination are the same as in the first embodiment of the present technology. That is, the physical header used determination process between the slave stations is the same as that of the first embodiment of the present technology.
Subsequently, each of the information processing devices 100 and 104 performs transmission / reception processing (445, 447). This transmission / reception processing is the same as that of the first embodiment of the present technology, except that transmission / reception is performed between slave stations instead of transmission / reception between the master station and slave stations. Further, the format of the PPDU in the seventh embodiment of the present technology is the same as that in the first embodiment of the present technology.
<8. Eighth Embodiment> In the seventh embodiment of the present technology, an example is shown in which the master station determines the physical header parameters used between the direct links. However, the slave station (the slave station that performs the direct link) may determine the physical header parameters used between the direct links.
Therefore, in the eighth embodiment of the present technology, an example is shown in which the slave station (the slave station that performs the direct link) determines the physical header parameter used between the direct links.
The system configuration in the eighth embodiment of the present technology is the same as that in the seventh embodiment of the present technology. Therefore, the parts common to the seventh embodiment of the present technology are designated by the same reference numerals as those of the seventh embodiment of the present technology, and some of these descriptions will be omitted.
[Communication example]
FIG. 30 is a sequence chart showing an example of communication processing between the devices constituting the communication system 50 according to the eighth embodiment of the present technology.
Note that FIG. 30 is a modification of FIG. 29, and has some parts in common with FIG. 29. Therefore, a part of the description of the parts common to FIG. 29 will be omitted.
First, a direct link connection process is performed between the information processing devices 100, 104, and 200 (451). This direct link connection process is the same as that of the seventh embodiment of the present technology.
Subsequently, each of the information processing devices 100 and 104 performs physical header parameter determination processing (452, 453). As described above, in the eighth embodiment of the present technology, the slave stations (information processing devices 100 and 104) having a connection destination other than the master station autonomously determine the physical header parameters for the direct link. .. The physical header parameter determination process can be substantially the same as the process performed by the master station (information processing device 200) in the first embodiment of the present technology. However, the sample target of COL_self_near and COL_self_far is limited to the slave station (information processing device) that has a direct connection with the own device even if it has the same BSSID.
Subsequently, the physical header parameter sharing process is performed between the information processing devices 100 and 104 (454). In this way, each of the information processing apparatus 100 and 104 that performs the direct link periodically exchanges the physical header parameter for the direct link determined by the physical header parameter determination process between the direct links. Then, each of the information processing devices 100 and 104 grasps the operation expected by the direct link partner. The frame used for the exchange may be a data frame or a management frame.
Subsequently, each of the information processing devices 100 and 104 performs a physical header determination process (455, 457). In this way, each of the information processing devices 100 and 104 independently determines the physical header for each partner based on the parameters notified from the direct link partner, in addition to the parameters for the master station. The criteria and the like for this determination may be the same as in the first embodiment of the present technology.
Subsequently, each of the information processing devices 100 and 104 performs transmission / reception processing (456, 458). This transmission / reception processing is the same as that of the seventh embodiment of the present technology.
<9. Ninth Embodiment> In the first embodiment of the present technology, an example in which a Link Strength Category field is provided in the SIGNAL field of the IEEE802.11 standard is shown.
In the ninth embodiment of the present technology, an example of adding a field for storing information about the BSS identifier in addition to the Link Strength Category field is shown in the SIGNAL field of the IEEE802.11 standard. By storing the information regarding the BSS identifier in this way, the packet sorting accuracy can be further improved. The configuration of the information processing device according to the ninth embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
In addition, each process and each format in the ninth embodiment of the present technology has some parts in common with the first embodiment of the present technology. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
[PPDU format example]
FIG. 31 is a diagram showing an example of a PPDU format exchanged between the devices constituting the communication system 10 according to the ninth embodiment of the present technology.
Here, the example shown in FIG. 31 is the same as the example shown in FIG. 7 except that the BSS COLOR field is provided in the SIGNAL field. Therefore, the parts common to FIG. 7 are designated by the same reference numerals as those in FIG. 7, and some of these explanations will be omitted.
The PPDU is composed of Preamble301, SIGNAL331, Extension303, Service304, MPDU305, and FCS306.
In the ninth embodiment of the present technology, a "Link Strength Category" field and a "BSS COLOR" field for storing information (COLOR information) regarding the BSS identifier are provided as a part of the SIGNAL field of the physical header. In FIG. 31, the "Link Strength Category" field is shown as a Link Strength Category, and the "BSS COLOR" field is shown as a COLOR.
Here, the COLOR information (BSS COLOR information) is information previously notified from the connected remote device (for example, the master station), and identifies the BSS (Basic Service Set) to which the own device belongs. Information that can be (eg, numerical value). That is, COLOR information (BSS COLOR information) is an example of an identifier for identifying a network. As similar information, BSSID is stored in the MAC header. However, the COLOR information can be expressed in the physical layer (PLCP layer) in a form more simplified than the BSSID.
In a and b of FIG. 31, when the information processing device (master station or slave station) that transmits the physical header belongs to the BSS in which "1" is set as the COLOR information (that is, COLOR = 1). An example is shown.
As described above, in the ninth embodiment of the present technology, the "Link Strength Category" field and the "COLOR" field are provided in the portion of SIGNAL 311 that is treated as Reserved. Thereby, the specific function in the ninth embodiment of the present technology can be realized without interfering with the reception of the Legacy device.
Further, in the ninth embodiment of the present technology, the physical header of Link Strength Category = 0 is referred to as "physical header for long distance". Further, the physical header of Link Strength Category = 1 is referred to as "physical header for short distance". The physical header transmitted from the Legacy device shall be treated as a "physical header for a long distance".
An information processing device (other than a legacy device) that receives a packet having at least one of the Link Strength Category field and the COLOR field can acquire the contents of each of these fields. Then, the information processing apparatus can change the detection threshold value to be applied and the reception operation based on the contents of each of these fields.
The connection process is the same as that of the first embodiment of the present technology. Further, the process of determining the physical header parameter is substantially the same as that of the first embodiment of the present technology. Here, the COLOR information is information that can be acquired in the physical layer. Therefore, unlike the BSSID information, the COLOR information can be used without waiting for the FCS (existing at the end of the PPDU) to be collated in the PPDU. Therefore, when determining the physical header parameters, when the master station collects information on the communication quality of packets from other BSS (OBSS), it classifies using COLOR information instead of BSSID. be able to.
Further, regarding the sharing process of the physical header parameters, the procedure and the first embodiment of the present technology are the same. However, in the ninth embodiment of the present technology, in addition to the "Multi Detect Parameter", the information of "COLOR" (BSS identifier in the physical layer) and "TxPower" (transmission power of the master station) is also added. introduce. Figure 32 shows an example of the frame format used in this case.
[Beacon frame format example]
FIG. 32 is a diagram showing an example of a beacon frame format exchanged between the devices constituting the communication system 10 according to the ninth embodiment of the present technology. Since FIG. 32 is a modification of FIG. 14, the parts common to FIG. 14 are designated by the same reference numerals as those in FIG. 14, and a part of these explanations will be omitted.
Figure 32 shows an example of adding new elements "COLOR Info" 341 and "TxPower Info" 342 to Payload 340 along with "Multi Detect Parameter" 311.
The BSS identifier in the physical layer is stored in "COLOR Info" 341. This BSS identifier corresponds to the BSS identifier stored in the "BSS COLOR" field shown in FIG.
The "TxPower Info" 342 stores information regarding the transmission power of the information processing device (for example, the master station) that transmits the beacon.
For example, the control unit of the information processing device 200 transmits a beacon in which each information is stored in "Multi Detect Parameter" 311 and "COLOR Info" 341 and "TxPower Info" 342 to a surrounding information processing device to notify the information.
The information processing apparatus that has received the notification by the beacon acquires and holds each information stored in "Multi Detect Parameter" 311 and "COLOR Info" 341 and "TxPower Info" 342 from the beacon. That is, the information processing device holds the contents of the "Multi Detect Parameter", the BSS identifier in the physical layer, and the transmission power of the communication partner (for example, the master station).
If the information contained in the subsequent beacon changes after the content of the beacon is retained, the information contained in the latest beacon (latest information) is adopted and retained.
Further, the master station may notify the contents of the "Multi Detect Parameter", the BSS identifier at the physical layer, and the transmission power of the own device by using a signal other than the beacon transmission. For example, the master station may notify the subordinate terminal in a unicast data frame or a management frame by using a judgment by its own device or an information acquisition request from the subordinate terminal as a trigger.
[Backoff processing example]
FIG. 33 is a diagram showing the flow of backoff processing in the IEEE 802.11 standard. In FIG. 33, the horizontal axis is shown as the time axis. Further, on the upper side of the horizontal axis, the state of the information processing apparatus (BUSY500 to 502, IFS, Tx503) is schematically shown by a rectangle. Further, on the lower side of the horizontal axis, a numerical value indicating the number of backoff slots (backoff counter) is shown. Further, the timing of the transmission request 504 from the upper layer and the timing of the random backoff time generation 505 are schematically shown by rectangles and arrows.
For example, if the carrier sense state changes to the IDLE state after becoming BUSY, the IFS waiting time will be entered every time. For example, if the IDLE state is entered after BUSY 500 to 502, the IFS waiting time is entered. Further, as shown by the numerical value on the lower side of the horizontal axis shown in FIG. 33, the backoff counter remains stopped while the physical header is being received.
[Example of backoff processing when canceling reception]
FIG. 34 is a diagram showing a flow of backoff processing by the information processing apparatus 100 according to the ninth embodiment of the present technology. The values representing the horizontal axis, the state of the information processing device on the upper side of the horizontal axis (BUSY 510 to 512, IFS), and the number of backoff slots on the lower side of the horizontal axis (backoff counter) shown in FIG. 34 are the same as in FIG. 33. Is.
Further, FIG. 34 shows an example in which two information processing devices 521 and 522 existing at positions far from the information processing device 100 transmit packets. The horizontal axis and the state of the information processing device (PLCP513, 514, PSDU) on the upper side of the horizontal axis with respect to the information processing devices 521 and 522 are the same as in FIG.
FIG. 34 shows an example in which, when the information processing device 100 receives a packet transmitted from each of the information processing devices 521 and 522, the reception is terminated based on the PLCP513 and 514 included in the packet (515). , 516). As a result, the period of BUSY511 and 512 can be shortened.
However, for example, in an environment where information processing devices are densely packed and traffic is congested, the backoff counter does not decrease even if reception from a distant information processing device is cut off and a transition to the IDLE state is performed. Is also assumed. For example, as shown in FIG. 34, even when the reception of packets from the information processing devices 521 and 522 is stopped (515, 516), the backoff counter remains "8" and does not decrease from "8". It becomes a state. In this way, even if the frame reception that is judged to be negligible is canceled, the IFS is added after the transition from BUSY to IDLE, so that the backoff counter does not decrease during this IFS. Further, the information processing apparatus 100 cannot perform transmission until the backoff counter becomes 0. As described above, in a dense environment (congested environment), there is a possibility that the transmission opportunity cannot be increased even if the reception of a negligible packet is terminated. Therefore, it is important to enhance the effect of acquiring the transmission opportunity of the information processing apparatus 100. FIG. 35 shows an example of improving the transmission opportunity of the information processing apparatus 100.
[Example of backoff processing when subtracting the backoff counter without inserting IFS]
FIG. 35 is a diagram showing a flow of backoff processing by the information processing apparatus 100 according to the ninth embodiment of the present technology. Since FIG. 35 is an example corresponding to FIG. 34, the parts common to FIG. 34 will be described with the same reference numerals.
In FIG. 35, when the information processing device 100 receives a packet transmitted from each of the information processing devices 521 and 522, as in FIG. 34, the reception is based on PLCP513 and 514 included in the packet. Here is an example of censoring (515, 516). Further, in FIG. 35, the back-off counter is subtracted as if the IDLE state was set for the time (elapsed time) related to the reception together with the reception termination (reception cancellation). Further, in FIG. 35, immediately after the reception is terminated (reception canceled), the IFS wait is not performed (that is, the IFS is not inserted), and the backoff counter is subtracted.
For example, as shown in FIG. 35, when the reception of the packet from the information processing device 521 is stopped (515), the time length from the start time of the physical header to the current time is calculated. Then, the time slot conversion value of the length (time length) is subtracted from the backoff counter at once. For example, "4 (= 8-4)" is calculated as the time length from the start time of the physical header to the current time. Then, the value "4" is subtracted from the backoff counter "8" to set the backoff counter to "4". In addition, the application of IFS prior to the subsequent carrier sense will be canceled, and the decrement subtraction of the backoff counter will be started immediately.
In this way, by canceling the application of IFS and subtracting the backoff counter for the physical header time, it is possible to effectively acquire the transmission opportunity.
Here, when EDCA (enhanced distributed channel access) is used, a plurality of backoff counters may be operating. Therefore, when a plurality of backoff counters are operating, this process is performed for all the counters.
In this way, the control unit 150 of the information processing apparatus 100 can control so as not to generate a waiting time corresponding to IFS after the packet reception is terminated. In this case, after the reception of the packet is cut off, the control unit 150 converts the time length from the time when the carrier sense transitions to BUSY to the reception cutoff time at the time of receiving the packet into a slot time and subtracts it from the backoff counter. can do.
Here, in the subtraction process described above, it is assumed that the backoff counter after the subtraction has a negative value. In such a case, the counter can be set to 0. That is, when the result after subtraction becomes a negative value, the control unit 150 of the information processing apparatus 100 can treat the result as 0.
Further, as another variation, when the backoff counter after subtraction becomes a negative value, the absolute value may be folded back and used. For example, if the counter value before subtraction is 1 and the time slot conversion value of the time length that was BUSY is 2, the counter value after subtraction "-1 (= 1-2)" is folded back. You can leave the value at 1. As a result, when there is another information processing apparatus having the same condition that the counter value before subtraction is 2, it is possible to reduce the case where the count becomes 0 at the same time and causes a collision. However, when wrapping, wrapping that causes the result to be larger than the counter value before subtraction is prohibited. That is, when the result after subtraction becomes a negative value, the control unit 150 of the information processing apparatus 100 positively folds the negative value so as not to exceed the backoff counter before the subtraction. Can be a value.
As another variation, when the backoff counter after subtraction becomes a negative value, a random number is generated in the range between the value below the backoff counter value before subtraction and 0, and that value is subtracted. It may be set to a later value. That is, the random backoff may be performed within the range of the value of the backoff counter before the original Busy.
In this example, the carrier sense of the physical layer has been described. However, when transmission is suppressed by the virtual carrier sense and the state is in the BUSY state, the above-mentioned processing at the time of discontinuing reception can be prevented.
[Operation example of physical header determination process]
FIG. 36 is a flowchart showing an example of a processing procedure of the physical header used determination process (selection process of the physical header for transmission) by the information processing apparatus 100 in the ninth embodiment of the present technology. This physical header determination process is basically the same as that of the first embodiment of the present technology, except that RSSI_peer is corrected based on TxPower notified by the other party.
First, the control unit 150 of the information processing device 100 monitors received packets from a destination connected to the own device and acquires RSSI for each destination (step S781). The RSSI (monitor result) obtained in this way is called RSSI_peer.
When the measured value of the received packet from the destination connected to the own device is held, the control unit 150 of the information processing device 100 reads the measured value and acquires the RSSI for each destination. May be (step S781).
Here, in the case of an information processing device (for example, information processing device 100) connected to a master station (for example, information processing device 200), the destination is basically only the master station. In this case, the reception level of the beacon in the past may be used as the monitor result.
Subsequently, the control unit 150 of the information processing apparatus 100 corrects the acquired RSSI_peer in consideration of the transmission power difference (step S782). For example, let TP_peer be the "TxPower" information (stored in "TxPower Info" 342 shown in FIG. 32) notified from the master station in the physical header parameter sharing process. Further, the transmission power used by the information processing apparatus 100 for transmission to the master station is TP_self. In this case, the corrected RSSI_adjusted can be obtained by the following equation 13. Here, Equation 13 is a description assuming a logarithmic (dB) calculation. RSSI_adjusted = RSSI_peer + (TP_self-TP_peer) ... Equation 13
Here, RSSI_adjusted indicates an estimated value of RSSI expected when the transmission from the information processing apparatus 100 is received on the master station side. However, if the information corresponding to TP_peer cannot be obtained, RSSI_adjusted may be substituted by RSSI_peer.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the corrected RSSI_adjusted with the application level L_near of the physical header, and determines the index of the physical header used by the own apparatus for transmission based on the comparison result. (Step S783). The application level L_near of the physical header is included in the beacon transmitted from the information processing apparatus 200.
For example, when the corrected RSSI_adjusted exceeds the application level L_near of the physical header, the control unit 150 of the information processing apparatus 100 sets the index of the physical header used by the own device for transmission to 1 (for short distance). Determine (step S783). On the other hand, when the corrected RSSI_adjusted is equal to or lower than the application level L_near of the physical header, the control unit 150 of the information processing apparatus 100 determines that the index of the physical header used by the own device for transmission is 0 (for long distance). (Step S783).
If the index of the physical header used by the own device for transmission has already been determined and a new index is determined, the already determined index is updated to the new index ( Step S783).
In addition, in FIG. 36, an example of determining the physical header to be used based on the classification of two values of short distance and long distance is shown, but the physical header to be used is determined based on the classification of three values or more (N value). It may be. For example, the application levels of each physical header are L_0, L_1, ..., and L_N in order from the longest distance. In this case, n that satisfies the following relational expression (Equation 14) is selected as the index of the physical header used for transmission. Here, Equation 14 is a description assuming a logarithmic (dB) calculation. L_n RSSI_adjusted <L_n + 1 ... Equation 14 However, n = 0 to N.
Note that FIG. 36 has described an example of operation on the slave station side in the case of uplink transmission from the slave station side to the master station side, but in the case of downlink transmission, the same operation should be performed on the master station side. It may be. The processing content on the master station side in this case is the same as the processing content shown in FIG. However, when there are multiple connection partners, the classification of the monitor result of the received packet shall be managed for each packet source, and RSSI_adjusted shall be calculated individually for each link.
Further, although FIG. 36 shows an example in which RSSI is used, the correlation output intensity COL may be used instead of RSSI.
[Operation example of transmission / reception processing]
FIG. 37 is a flowchart showing an example of a processing procedure of transmission / reception processing by the information processing apparatus 100 according to the ninth embodiment of the present technology. Although the information processing device 100 will be described with reference to FIG. 37, the same can be applied to other information processing devices (for example, the information processing device 200). That is, this transmission / reception processing is the same on both the master station side and the terminal side.
The control unit 150 of the information processing apparatus 100 performs packet detection / reception determination processing during a time other than transmission and reception (step S800). This packet detection / reception determination process will be described in detail with reference to FIG. 39.
Subsequently, the control unit 150 of the information processing apparatus 100 determines whether or not there is a packet to be transmitted (step S791). If there is no packet to be transmitted (step S791), the operation of transmission / reception processing is terminated.
If there is a packet to be transmitted (step S791), the control unit 150 of the information processing device 100 determines whether or not the information processing device 100 has acquired the transmission right (step S792).
Here, the state in which the transmission right is acquired means, for example, a state in which the backoff counter that is decremented according to the time when the carrier sense result is IDLE is 0.
When the information processing apparatus 100 has acquired the transmission right (step S792), the control unit 150 of the information processing apparatus 100 transmits a packet (step S794). If the information processing device 100 has not acquired the transmission right (step S792), the control unit 150 of the information processing device 100 determines whether or not the packet to be transmitted is an immediate response to the packet received from the communication partner. Is determined (step S793).
The packet that becomes an immediate response to the packet received from the communication partner is, for example, a CTS frame, an ACK frame, or a Block Ack frame.
If the packet to be transmitted is not an immediate response to the packet received from the communication partner (step S793), the operation of the transmission / reception process is terminated without transmitting the packet. When the packet to be transmitted is an immediate response to the packet received from the communication partner (step S793), the control unit 150 of the information processing apparatus 100 transmits the packet (step S794). In this way, the transmission of the packet, which is an immediate response to the packet received from the communication partner, can be performed regardless of the carrier sense state.
As described above, the information processing apparatus 100 has a packet to be transmitted and has acquired the transmission right, and the packet to be transmitted is an immediate response to the packet from the communication partner. To send.
In this case, the control unit 150 of the information processing apparatus 100 determines the physical header in the format shown in a or b of FIG. 31 based on the index of the physical header determined in the physical header determination process to be used when transmitting the packet. Use to send.
Further, the control unit 150 of the information processing device 100 can receive, for example, the modulation used for the data unit with a high probability by the destination device according to the detection threshold value corresponding to the determined physical header. Select a coding method and use it to send. Further, the control unit 150 of the information processing apparatus 100 uses, for example, a modulation and communication path coding method (MCS) that the destination apparatus can receive with a high probability according to the detection threshold value corresponding to the determined physical header. You may select and send.
[Operation example of packet detection / reception judgment processing]
FIG. 38 is a diagram showing an example (processing classification table) of the relationship between the processing performed by the information processing apparatus 100 and the physical header in the ninth embodiment of the present technology. Note that FIG. 38 will be described in detail with reference to FIG. 39.
FIG. 39 is a flowchart showing a packet detection / reception determination process (processing procedure in step S800 shown in FIG. 37) in the transmission / reception processing by the information processing apparatus 100 according to the ninth embodiment of the present technology.
First, the control unit 150 of the information processing apparatus 100 measures RSSI for the signal input via the antenna 141, and holds the RSSI obtained by the measurement (step S801). Further, the control unit 150 of the information processing apparatus 100 performs the correlation calculation of the Preamble pattern and obtains the correlator output (step S801). This correlator output means the above-mentioned correlation output intensity COL. That is, the correlator output is not the normalized correlator output level, but the correlator output converted to reflect the received power.
As described above, each of the master station and the slave station corresponding to each function in the ninth embodiment of the present technology measures RSSI for the signal input through the antenna while in the standby state. Monitor the correlator output (step S801).
Subsequently, the control unit 150 of the information processing apparatus 100 performs a pattern correlation calculation and compares the output (correlator output) with the provisional detection threshold value (step S802). Here, the provisional detection threshold is a detection threshold for reading the SINGAL field prior to the main determination process. As the provisional detection threshold, for example, a value that is equal to or less than both PD_near and PD_far can be used. Further, for example, PD_default may be used as the provisional detection threshold value.
When the value of the correlator output is equal to or less than the provisional detection threshold value (step S802), the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the energy detection threshold value ED (step S803). Then, the control unit 150 of the information processing apparatus 100 determines whether or not the RSSI exceeds the energy detection threshold value ED (step S803). This energy detection threshold ED can be the same as the above-mentioned value.
When the RSSI exceeds the energy detection threshold value ED (step S803), the control unit 150 of the information processing apparatus 100 maintains the carrier sense BUSY state (step S804) and operates the packet detection / reception determination process. To finish. On the other hand, when the RSSI is equal to or less than the energy detection threshold value ED (step S803), the control unit 150 of the information processing apparatus 100 transitions to the carrier sense IDLE state (step S805) to perform packet detection / reception determination processing. End the operation.
When the value of the correlator output exceeds the provisional detection threshold value (step S802), the control unit 150 of the information processing apparatus 100 determines that it is in the provisional detection state and transitions to the carrier sense BUSY state (step). S806). Subsequently, the control unit 150 of the information processing apparatus 100 decodes the subsequent SIGNAL field in the physical header and reads out the information and the like in the SIGNAL field (step S807). Specifically, each of the "Link Strength Category" field, the "COLOR" field, and the CRC (Cyclic Redundancy Check) of the physical header is read out. As mentioned above, the "Link Strength Category" field contains information indicating the detection threshold to be applied.
Further, the control unit 150 of the information processing apparatus 100 collates each read information with the processing classification table shown in FIG. 38, and determines the subsequent processing (step S807).
Specifically, the control unit 150 of the information processing apparatus 100 calculates the CRC of the physical header and confirms the presence or absence of an error in the physical header. Here, if there is an error in the physical header, the validity of the field value cannot be confirmed. Therefore, as shown in FIG. 38, when there is an error in the physical header, the subsequent processing is determined as "reception termination (ERROR)". If there is no error in the CRC of the physical header, the processing is determined based on the contents of the "Link Strength Category" field and the "COLOR" field.
Here, the control unit 150 of the information processing apparatus 100 determines the detection threshold value to be applied based on the Preamble Detection Threshold shared in the above-mentioned physical header parameter sharing process. Specifically, when Link Strength Category = 0, the detection threshold PD_far is used, and when Link Strength Category = 1, the detection threshold PD_near is used. However, when a physical header that does not have the Link Strength Category field is provisionally detected, the lowest level value (for example, PD_far) can be used as the detection threshold value.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the determined detection threshold value with the value of the correlator output. Then, when the value of the correlator output is smaller than the determined detection threshold value, the subsequent processing is determined as "reception censored (IDLE)" as shown in the upper part of FIG. 38. However, as shown in the upper part of FIG. 38, when the COLOR field exists and the value of the COLOR field is the same as the value of the BSS to which the own device belongs, the subsequent processing is exceptionally "received". ". As a result, it is possible to avoid a case where the detection of the packet that should be originally received fails due to the fluctuation of the reception level.
When the value of the correlator output is equal to or higher than the determined detection threshold value, the subsequent processing is determined to be "reception" as shown in the lower part of FIG. 38. However, as shown in the lower part of Fig. 38, if the COLOR field exists and the value of the COLOR field is different from that of the BSS to which the own device belongs, the subsequent processing is exceptionally "reception cutoff (reception cutoff (). BUSY) "is decided. As a result, it is possible to avoid a case where the detection of a desired packet fails due to the reception of a packet that does not originally need to be received.
In this way, the control unit 150 of the information processing apparatus 100 performs any of "reception", "reception cutoff (IDLE)", "reception cutoff (BUSY)", and "reception cutoff (ERROR)" as subsequent processing. Determine (step S807).
Here, for example, in the case of a device in the own BSS, when the detection threshold value for a long distance is used, it is assumed that the packet arrives at a weak level. Therefore, when the threshold value to be compared (detection threshold value for long distance) and the detection level are inconsistent, it can be estimated that the packet is from another BSS. In this case, reception can be terminated. For example, when a long-distance detection threshold is used and the RSSI is very high, reception can be aborted.
Therefore, here, in the processing classification table shown in FIG. 38, if the COLOR field does not exist and the value of the correlator output is equal to or greater than the determined detection threshold value (threshold value to be applied), the following. An example of modification when the process is determined to be "received" is shown. For example, in that case, if the value of the correlator output is significantly larger than the threshold to be applied (for example, if it is larger than a certain value), the subsequent processing is "BUSY" or "receive censored". (IDLE) .
For example, if the "Link Strength Category" in the PLCP header does not give the highest level of detection threshold, and the value of the correlator output is significantly higher than the determined detection threshold (threshold to be applied). Assume a large case. For example, when the physical header to be used is determined based on the binary classification of short distance and long distance, the detection threshold value for long distance is a value that does not give the highest level detection threshold value. In such a case, if the value of the correlator output is significantly larger than the threshold value to be applied, it is considered that the threshold value to be applied and the value of the correlator output are largely inconsistent. It can be inferred that such a state occurs when a packet transmitted from another BSS is detected. Therefore, in such a case, it is possible to discontinue the reception because it is not necessary to perform the reception to the end.
Further, for example, when the physical header to be used is determined based on the classification of three values, it is assumed that the first detection threshold value, the second detection threshold value, and the third detection threshold value are set in descending order of the detection threshold value. In this case, the second detection threshold or the third detection threshold is a value that does not give the highest level of detection threshold. In this case, for example, when the threshold value to be applied is the third detection threshold value and the value of the correlator output exceeds the second detection threshold value, the threshold value to be applied and the value of the correlator output are largely inconsistent. It can be judged that they are consistent. Similarly, for example, when the threshold value to be applied is the second detection threshold value and the value of the correlator output exceeds the first detection threshold value, the threshold value to be applied and the value of the correlator output are largely inconsistent. It can be judged that it is doing. It can be inferred that such a state is a case where a packet transmitted from another BSS is detected, as in the case of the above-mentioned binary value, and reception can be terminated. In particular, when the threshold value to be applied is the third detection threshold value and the value of the correlator output exceeds the first detection threshold value, it is highly likely that a packet transmitted from another BSS was detected. Conceivable.
Further, for example, when the physical header to be used is determined based on the classification of 4 values or more, it is possible to terminate the reception when it is estimated that the packet transmitted from another BSS is detected. ..
Further, based on the comparison result between the threshold value and the value of the correlator output, it is possible to determine whether to perform "reception censoring (BUSY)" or "reception censoring (IDLE)". For example, when the value of the correlator output is higher than a certain detection threshold value (threshold value to be applied) by a certain value or more (for example, 20 dB or more), it is treated as an inconsistency. Then, if it is treated as inconsistent and the value of the correlator output exceeds the threshold value one step higher than the "Link Strength Category" in the PLCP header, it can be regarded as "reception cutoff (BUSY)". .. For example, when the physical header to be used is determined based on the binary classification of short-distance and long-distance, the threshold one step higher is the detection threshold for short-distance. In addition, it is treated as inconsistent and the value of the correlator output is "Link Strength" in the PLCP header. If the threshold value one step higher than "Category" is not exceeded, it can be set as "Reception cutoff (IDLE)". For example, if the physical header used is determined based on the binary classification of short-distance and long-distance, the value of the correlator output will be between the short-distance detection threshold and the long-distance detection threshold. In that case, it can be "reception cutoff (IDLE)".
Further, even when the COLOR information does not exist in the SIGNAL field, the processing classification may be set to "reception cutoff (IDLE)" or "reception cutoff (BUSY)" depending on the strength of the correlator output and the contents of the SIGNAL field. .. For example, if the format described in the SIGNAL field is not supported by the own device, the processing classification is usually set to "reception cutoff (BUSY)". As an exception, if the format described in the SIGNAL field is not supported by the own device and the intensity of the correlator output is less than or equal to a predetermined level, the processing classification is "IDLE". May be.
When "reception" is determined as the subsequent processing (step S808), the control unit 150 of the information processing apparatus 100 continuously receives the temporarily detected packet until the end (step S809). If the received packet is addressed to the own device and an immediate response is requested, a physical header having the same "Link Strength Category" field as the target packet is added and transmitted. That is, the part in which the information regarding the detection threshold value in the SIGNAL field is stored is the same, and the information determined by the own device is stored in the other parts (for example, MCS, length).
When "reception cutoff (BUSY)" is determined as the subsequent processing (step S808), the control unit 150 of the information processing apparatus 100 cuts off the reception of the temporarily detected packet at the end of the physical header and puts it in the standby state. Back (step S810). However, the carrier sense state is treated as BUSY until the end time of the packet (step S811). Further, the frame interval (IFS (Inter Frame Space)) before the next transmission attempt is set to AIFS (Arbitration IFS) or DIFS (Distributed coordination function IFS).
When "reception cutoff (IDLE)" is determined as the subsequent processing (step S808), the control unit 150 of the information processing apparatus 100 cuts off the reception of the temporarily detected packet at the end of the physical header and puts it in the standby state. Back (step S812). Note that steps S807 to S812 are examples of the first procedure.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the energy detection threshold value ED (step S813). Then, when the measured RSSI exceeds the energy detection threshold ED (step S813), the control unit 150 of the information processing apparatus 100 maintains the carrier sense state as the BUSY state (step S814). Also, let the frame interval (IFS) before the next transmission attempt be AIFS or DIFS.
When the measured RSSI is equal to or less than the energy detection threshold ED (step S813), the control unit 150 of the information processing apparatus 100 transitions the carrier sense state to the IDLE state (step S815).
In this way, when the IDLE state is entered (steps S815 and S816), the frame interval (IFS) before the next transmission attempt is set to AIFS (step S819). Then, the carrier sense is treated as IDLE by going back to the Preamble start time (or the physical header start time) of the packet whose reception is cut off, and a process is performed in which the detection is not detected (step S820).
Specifically, as in the example shown in FIG. 35, the time length when the physical carrier sense result was BUSY (the time length from the packet detection judgment time by Preamble or the time length from the start time of the physical header to the current time) is calculated. To do. Then, the time slot conversion value of that length is subtracted from the backoff counter at once. In addition, the application of IFS prior to the subsequent carrier sense is also canceled, and the subtraction of the backoff counter is immediately started (step S820). If the backoff counter after subtraction becomes a negative value, set it to 0 as described above, and use the absolute value by folding back the value, which is less than or equal to the value of the backoff counter before subtraction. The value of the random number generated in the range between 0 and 0 can be used as the value after subtraction.
If "reception cutoff (ERROR)" is determined as the subsequent processing (step S808), the control unit 150 of the information processing apparatus 100 cuts off the reception of the temporarily detected packet at the end of the physical header and stands by. Return to state (step S812).
Subsequently, the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the energy detection threshold value ED (step S813). Then, when the measured RSSI exceeds the energy detection threshold ED (step S813), the control unit 150 of the information processing apparatus 100 maintains the carrier sense state as the BUSY state (step S814). In addition, Pake Tsu door is the error handling, the front of the frame interval of the next transmission attempts (IFS) and EIFS (Extended IFS).
When the measured RSSI is equal to or less than the energy detection threshold ED (step S813), the control unit 150 of the information processing apparatus 100 transitions the carrier sense state to the IDLE state (step S815).
Further, since "reception cutoff (ERROR)" is determined as the subsequent processing (step S816), the frame interval (IFS) before the next transmission attempt is set to EIFS (step S817). Then, the control unit 150 of the information processing apparatus 100 determines whether or not the correlator output intensity is smaller than the minimum detection threshold value (step S818). That is, it is determined whether or not the correlator output intensity is smaller than the minimum detection threshold value in the Preamble Detection Threshold shared in the PLCP header parameter sharing process described above (step S818).
If the correlator output intensity is less than the minimum detection threshold (step S818), the process proceeds to step S820. That is, the control unit 150 of the information processing device 100 treats the carrier sense as IDLE by going back to the preamble start time (or the physical header start time) of the truncated packet, and performs a process assuming that the carrier sense is not detected (step). S820). In addition, steps S807, S808, S812, S813, S815 to S820 are an example of the second procedure.
In this way, it is possible to more effectively acquire a transmission opportunity by discontinuing reception and transitioning to the IDLE state.
Here, when the IEEE802.11 standard is assumed, the detection threshold value of the L-STF unit can be used as the detection threshold value in the ninth embodiment of the present technology. However, instead of the detection threshold value of the L-STF part, the detection threshold value of the L-LTF part may be used, or the detection threshold value common to both the L-STF part and the L-LTF part may be used. Good. Further, the detection thresholds of the L-STF part and the L-LTF part may be changed independently, and may be extended so that both are specified as physical header parameters.
In this way, the control unit 150 of the information processing apparatus 100 controls to stop the reception of the packet in the middle according to the first condition. In this case, the control unit 150 of the information processing apparatus 100 can operate the time from the start of reception of the packet to the termination of reception of the packet as if the carrier sense was idle, according to the second condition. ..
For example, the first condition can be that the COLOR information specified in the physical header of the received packet is different from the COLOR information of the network to which the information processing apparatus 100 belongs. Further, for example, the first condition is that the preamble correlator output level of the packet being received in terms of antenna input is lower than the packet detection threshold derived from the information described in the physical header of the packet. can do. In this case, the control unit 150 can derive the index based on the association between the index described in the physical header of the packet and the table of threshold values shared in advance.
Further, for example, the first condition can be that the CRC calculation result for the physical header portion of the received packet matches the CRC described in the physical header.
Further, for example, the second condition can be that the received power of the packet being received falls below a predetermined energy detection threshold value. Further, for example, it can be set as the second condition that transmission suppression by virtual carrier sense is not applied at the time when the reception of the packet is terminated.
Further, for example, the condition relating to the CRC calculation result for the physical header portion in the packet and the preamble correlator output level in terms of antenna input can be set as the second condition. For example, the CRC calculation result does not match the CRC information described in the physical header, and the preamble correlator output level is below the minimum applicable packet detection threshold. It can be the second condition. In this case, the control unit 150 of the information processing apparatus 100 can determine the necessity of operation by using the second condition.
Further, for example, when the control unit 150 of the information processing device 100 does not satisfy the second condition after the packet reception is terminated, the control unit 150 of the information processing device 100 prohibits the transmission from the information processing device 100 during the duration of the packet transfer. May be good. However, in this case, when the control unit 150 is addressed to the information processing device 100 and receives a frame requesting a response, the control unit 150 may transmit a response to the frame.
Further, for example, the first condition may be included in the second condition.
Further, for example, when the control unit 150 of the information processing apparatus 100 satisfies the packet detection condition (for example, when the value of the correlator output is equal to or higher than the determined detection threshold value), the control unit 150 "receives" the subsequent processing. To decide. However, when the COLOR information exists in the COLOR field and the COLOR information is different from the COLOR information of the network to which the information processing apparatus 100 belongs, the subsequent processing is determined as "reception cutoff (IDLE)". That is, the reception of the packet is cut off and the state returns to the standby state.
Further, for example, when the control unit 150 does not satisfy the packet detection condition (for example, when the value of the correlator output is smaller than the determined detection threshold value), the subsequent processing is "discontinued (IDLE)". ". However, when the COLOR information exists in the COLOR field and the COLOR information matches the COLOR information of the network to which the information processing apparatus 100 belongs, the subsequent processing is determined to be "received". That is, the reception processing of the packet is continued.
<10. Tenth Embodiment> In the fourth embodiment of the present technology, an example of defining a plurality of Preamble series is shown. In the tenth embodiment of the present technology, as in the fourth embodiment of the present technology, a plurality of Preamble series are defined, and an example in which the selection accuracy is further improved by using the COLOR information together is shown. The configuration of the information processing device according to the tenth embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
Further, the tenth embodiment of the present technology is a modification of the fourth embodiment of the present technology. Therefore, each process and each format in the tenth embodiment of the present technology also has a part in common with the fourth embodiment of the present technology. Therefore, the parts common to the fourth embodiment of the present technology are designated by the same reference numerals as those of the fourth embodiment of the present technology, and some of these descriptions will be omitted.
[PPDU format example]
FIG. 40 is a diagram showing an example of the format of PPDU exchanged between the devices constituting the communication system 10 according to the tenth embodiment of the present technology.
Here, the example shown in FIG. 40 is the same as the example shown in FIG. 21 except that the BSS COLOR field is provided in the SIGNAL field. Therefore, the parts common to FIG. 21 are designated by the same reference numerals as those in FIG. 21, and some of these descriptions will be omitted.
The PPDU is composed of Preamble311, SIGNAL351, Extension303, Service304, MPDU305, and FCS306.
Here, in the tenth embodiment of the present technology, a "BSS COLOR" field for storing information (COLOR information) regarding the BSS identifier is provided as a part of the SIGNAL field of the physical header. In FIG. 40, the "BSS COLOR" field is shown as COLOR. The BSS COLOR information is the same as that shown in the ninth embodiment of the present technology.
Further, in a and b of FIG. 40, when the information processing device (master station or slave station) that transmits the physical header belongs to the BSS in which "1" is set as the COLOR information (that is, COLOR = 1). ) Is shown.
As described above, in the tenth embodiment of the present technology, the "COLOR" field is provided in the portion of the SIGNAL 311 that is treated as Reserved.
The connection process is the same as that of the first embodiment of the present technology. Further, the ninth embodiment and the procedure of the present technology are the same for the physical header parameter determination process, the physical header parameter sharing process, and the physical header determination process to be used.
Further, the transmission / reception processing is the same as that of the ninth embodiment of the present technology except for the packet detection / reception determination processing (processing procedure of step S800 shown in FIG. 37). Therefore, the packet detection / reception determination process will be described with reference to FIGS. 41 and 42.
[Operation example of packet detection / reception judgment processing]
FIG. 41 is a diagram showing an example (processing classification table) of the relationship between the processing performed by the information processing apparatus 100 and the physical header in the tenth embodiment of the present technology. Note that FIG. 41 will be described in detail with reference to FIG. 42.
FIG. 42 is a flowchart showing a packet detection / reception determination process (processing procedure in step S800 shown in FIG. 37) among transmission / reception processes by the information processing apparatus 100 according to the tenth embodiment of the present technology.
First, the control unit 150 of the information processing apparatus 100 measures RSSI for the signal input via the antenna 141, and holds the RSSI obtained by the measurement (step S821).
Subsequently, the control unit 150 of the information processing apparatus 100 compares the measured RSSI with the applied level (L_far and L_near) of each physical header held, and determines the index of the physical header applied to the detection. (Step S822). For example, the index of the physical header applied to the detection can be determined in the same manner as the selection method of selecting the physical header for transmission of the own device.
For example, the control unit 150 of the information processing device 100 compares the measured RSSI with the value of L_near, and if the measured RSSI exceeds L_near, the physical header used for the correlation detection of the own device. Determine the index of 1 (for short distance). Further, when the measured RSSI is L_near or less, the control unit 150 of the information processing apparatus 100 determines the index of the physical header used for the correlation detection of the own apparatus to 0 (for long distance).
Subsequently, the control unit 150 of the information processing apparatus 100 performs the correlation calculation using the correlator corresponding to the preamble series generated by the different rules as described above for the physical header of the determined index (step S823). .. Here, the correlator output means the correlation output intensity COL, as in the first embodiment of the present technology. That is, the correlator output is not the normalized correlator output level, but the correlator output converted to reflect the received power.
Subsequently, the control unit 150 of the information processing apparatus 100 compares the correlator output of the selected correlator with the detection threshold value of the physical header at the determined index, and the value of the correlator output determines the detection threshold value. Determine if it is exceeded (step S824).
If the value of the correlator output exceeds the detection threshold (step S824), the control unit 150 of the information processing apparatus 100 decodes the subsequent SIGNAL field in the physical header and enters the SIGNAL field. Read information etc. (step S825). Specifically, each of the "COLOR" field and the CRC of the physical header is read. Then, the control unit 150 of the information processing apparatus 100 determines one of "reception", "reception cutoff (IDLE)", "reception cutoff (BUSY)", and "reception cutoff (ERROR)" as the subsequent processing. (Step S825).
Specifically, the control unit 150 of the information processing apparatus 100 calculates the CRC of the physical header and confirms the presence or absence of an error in the physical header. Here, if there is an error in the physical header, the validity of the field value cannot be confirmed. Therefore, as shown in FIG. 41, when there is an error in the physical header, the subsequent processing is determined as "reception termination (ERROR)".
If there is no error in the CRC of the physical header, the processing is decided based on the contents of the "COLOR" field. That is, if there is no error in the CRC of the physical header, the subsequent processing is basically determined as "receive". However, as shown in Fig. 41, if the COLOR field exists and the value of the COLOR field is different from the value of the BSS to which the own device belongs, the subsequent processing is exceptionally "BUSY". ) . As a result, it is possible to avoid a case where the detection of a desired packet fails due to the reception of a packet that does not originally need to be received.
The processing procedure (step S827) when "reception" is determined as the subsequent processing corresponds to the processing procedure (step S809) shown in FIG. 39. In addition, each processing procedure (step S828, S829) when "reception censored (BUSY)" is determined as the subsequent processing corresponds to each processing procedure (step S810, S811) shown in FIG. 39. Further, the processing procedure (steps S830 to S832) when "reception censored (IDLE)" or "reception censored (ERROR)" is determined as the subsequent processing is described in the processing procedure (steps S813 to S815) shown in FIG. Correspond.
If the value of the correlator output is equal to or less than the detection threshold value (step S824), the process proceeds to step S830. That is, when the value of the correlator output is equal to or less than the detection threshold value (step S824), the subsequent processing is not performed and the Preamble is left in the non-detection state.
<11. Eleventh Embodiment> In the ninth embodiment of the present technology, an example of determining the physical header parameter is shown. In the eleventh embodiment of the present technology, an example in which the physical header parameter determination process is omitted is shown.
The configuration of the information processing device according to the eleventh embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
The eleventh embodiment of the present technology is a modification of the ninth embodiment of the present technology. Therefore, each process and each format in the eleventh embodiment of the present technology also has a part in common with the ninth embodiment of the present technology. Therefore, the parts common to the ninth embodiment of the present technology are designated by the same reference numerals as those of the ninth embodiment of the present technology, and a part of these explanations will be omitted.
[PPDU format example]
FIG. 43 is a diagram showing an example of the format of PPDU exchanged between the devices constituting the communication system 10 according to the eleventh embodiment of the present technology.
Here, the example shown in FIG. 43 is the same as the example shown in FIG. 31, except that a Requested Detection Level is provided instead of the Link Strength Category in the SIGNAL field. Therefore, the parts common to FIG. 31 are designated by the same reference numerals as those in FIG. 31, and a part of these explanations will be omitted.
The PPDU is composed of Preamble301, SIGNAL361, Extension303, Service304, MPDU305, and FCS306.
Here, in the eleventh embodiment of the present technology, a "Requested Detection Level" field and a "BSS COLOR" field for storing COLOR information are provided as a part of the SIGNAL field of the physical header.
In this way, by providing the "Requested Detection Level" field in the SIGNAL field of the physical header, the information processing apparatus can directly specify the signal level desired to be used for the detection determination at the destination at the time of transmission. Here, it is assumed that the unit of the signal level and the quantization method are shared with the destination.
In addition, each information processing device changes the content of the "Requested Detection Level" field according to the quality of the link with the destination.
As described above, in the eleventh embodiment of the present technology, the "Requested Detection Level" field and the "COLOR" field are provided in the portion of the SIGNAL 361 that is treated as Reserved. Thereby, the specific function in the eleventh embodiment of the present technology can be realized without interfering with the reception of the Legacy device.
In addition, the information processing device (other than the legacy device) that has received the packet including the "Requested Detection Level" field can acquire the contents of the "Requested Detection Level" field. Then, the information processing apparatus can directly use the contents of the "Requested Detection Level" field as the detection threshold value to be applied.
The connection process is the same as that of the first embodiment of the present technology. Further, the process of determining the physical header parameter can be omitted as described above.
Further, in the eleventh embodiment of the present technology, the exchange of information regarding the detection application threshold value between the master station and the slave station can be omitted. Therefore, the process of sharing the physical header parameters can be omitted. However, in the eleventh embodiment of the present technology, the information of "COLOR" (BSS identifier in the physical layer) and "TxPower" (transmission power of the master station) is additionally transmitted. FIG. 44 shows an example of the frame format used in this case.
[Beacon frame format example]
FIG. 44 is a diagram showing an example of a beacon frame format exchanged between the devices constituting the communication system 10 according to the eleventh embodiment of the present technology. Since FIG. 44 is a modification of FIG. 32, the parts common to FIG. 32 are designated by the same reference numerals as those in FIG. 32, and a part of these explanations will be omitted.
FIG. 44 shows an example in which the Multi Detect Parameter 311 is omitted in the Payload 340 shown in FIG. Note that "COLOR Info" 371 and "TxPower Info" 372 correspond to "COLOR Info" 341 and "TxPower Info" 342 shown in FIG.
For example, the control unit of the information processing apparatus 200 transmits a beacon in which each information is stored in the COLOR Info 371 and the TxPower Info 372 to the surrounding information processing apparatus to notify the information.
The information processing apparatus that has received the notification by the beacon acquires and holds each information stored in "COLOR Info" 371 and "TxPower Info" 372 from the beacon. That is, the information processing device holds the contents of the BSS identifier in the physical layer and the transmission power of the communication partner (for example, the master station).
If the information contained in the subsequent beacon changes after the content of the beacon is retained, the information contained in the latest beacon (latest information) is adopted and retained.
Further, the master station may notify the contents of the BSS identifier in the physical layer and the transmission power of the own device by using a signal other than the beacon transmission. For example, the master station may notify the subordinate terminal in a unicast data frame or a management frame by using a judgment by its own device or an information acquisition request from the subordinate terminal as a trigger.
[Operation example of physical header determination process]
FIG. 45 is a flowchart showing an example of a processing procedure of the physical header used determination process (selection process of the physical header for transmission) by the information processing apparatus 100 in the eleventh embodiment of the present technology.
First, the control unit 150 of the information processing device 100 monitors received packets from a destination connected to the own device and acquires RSSI for each destination (step S841). The RSSI (monitor result (RSSI measurement result for each destination)) acquired in this way is defined as RSSI_peer. In the eleventh embodiment of the present technology, the RSSI information from the master station to which the information processing apparatus 100 is connected can be set as RSSI_peer.
When the measured value of the received packet from the destination connected to the own device is held, the control unit 150 of the information processing device 100 reads the measured value and acquires the RSSI for each destination. It may be (step S841).
Here, in the case of an information processing device (for example, information processing device 100) connected to a master station (for example, information processing device 200), the destination is basically only the master station. In this case, the reception level of the beacon in the past may be used as the monitor result.
Subsequently, the control unit 150 of the information processing apparatus 100 corrects the acquired RSSI_peer in consideration of the transmission power difference (step S842). For example, let TP_peer be the "TxPower" information (stored in "TxPower Info" 372 shown in FIG. 44) notified from the master station by the beacon. Further, the transmission power used by the information processing apparatus 100 for transmission to the master station is TP_self. In this case, the corrected RSSI_adjusted can be obtained by the following equation 13 (same as equation 13 in the ninth embodiment of the present technology). RSSI_adjusted = RSSI_peer + (TP_self-TP_peer) ... Equation 13
Here, RSSI_adjusted indicates an estimated value of RSSI expected when the transmission from the information processing apparatus 100 is received on the master station side. However, if the information corresponding to TP_peer cannot be obtained, RSSI_adjusted may be substituted by RSSI_peer.
Subsequently, the control unit 150 of the information processing apparatus 100 converts RSSI_adjusted to the application desired detection level Lreq by using the following equation 15. Here, Equation 15 is a description assuming a logarithmic (dB) calculation. L_req = RSSI_adjusted + O ... Equation 15
Here, O is the amount of margin offset with respect to the preamble detection error due to the fluctuation of the reception level. For example, O can be set to about -10 dB to -20 dB.
The value of the desired application detection level L_req thus obtained is quantized in a predetermined unit shared in advance and stored in the "Requested Detection Level" field 361 (the part "xx" shown in FIG. 43).
Further, although FIG. 45 shows an example of using RSSI, the correlation output intensity COL may be used instead of RSSI.
[Operation example of transmission / reception processing]
The transmission / reception processing is substantially the same as that of the ninth embodiment of the present technology, and only the classification table of the processing of the physical header after provisional detection is different. Therefore, FIG. 46 shows an example of the processing classification table used in the eleventh embodiment of the present technology.
FIG. 46 is a diagram showing an example (processing classification table) of the relationship between the processing performed by the information processing apparatus 100 and the physical header in the eleventh embodiment of the present technology.
In the ninth embodiment of the present technology, an example of acquiring the application detection threshold value from the threshold value list held in advance by using the "Link Strength Category" is shown. On the other hand, in the eleventh embodiment of the present technology, the detection threshold to be applied is directly described in the "Requested Detection Level" field. Therefore, in the eleventh embodiment of the present technology, the detection threshold value (application desired detection level Lreq) described in the Requested Detection Level field can be used as it is.
As described above, the processing classification table in the eleventh embodiment of the present technology has a different detection threshold to be applied from the processing classification table (shown in FIG. 38) in the ninth embodiment of the present technology. Since other processes are the same as those of the ninth embodiment of the present technology, the description thereof will be omitted here.
<12. 12th Embodiment> In the 1st embodiment of the present technology, an example in which a Link Strength Category field is provided in the SIGNAL field of the IEEE802.11 standard is shown.
In the twelfth embodiment of the present technology, an example is shown in which the Link Strength Category field is not provided in the SIGNAL field of the IEEE802.11 standard, but a field for storing information about the BSS identifier is provided. Further, in the twelfth embodiment of the present technology, an example in which packets are sorted only by the BSS identifier is shown. The configuration of the information processing device according to the twelfth embodiment of the present technology is substantially the same as the information processing devices 100 to 103, 200, and 201 shown in FIG. 1 and the like. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
In addition, each process and each format in the twelfth embodiment of the present technology also has some parts in common with the first embodiment of the present technology. Therefore, the parts common to the first embodiment of the present technology are designated by the same reference numerals as those of the first embodiment of the present technology, and some of these descriptions will be omitted.
[PPDU format example]
FIG. 47 is a diagram showing an example of the format of PPDU exchanged between the devices constituting the communication system 10 in the twelfth embodiment of the present technology.
Here, the example shown in FIG. 47 is the same as the example shown in FIG. 7 except that the BSS COLOR field is provided in the SIGNAL field instead of the Link Strength Category field. Therefore, the parts common to FIG. 7 are designated by the same reference numerals as those in FIG. 7, and some of these explanations will be omitted.
The PPDU is composed of Preamble301, SIGNAL381, Extension303, Service304, MPDU305, and FCS306.
In the twelfth embodiment of the present technology, a "BSS COLOR" field for storing information (COLOR information) regarding the BSS identifier is provided as a part of the SIGNAL field of the physical header. In FIG. 47, the "BSS COLOR" field is shown as COLOR.
In a of FIG. 47, an example in which the information processing device (master station or slave station) that transmits the physical header belongs to the BSS in which "1" is set as the COLOR information (that is, COLOR = 1). Shown. B in FIG. 47 corresponds to c in FIG.
Thus, in the twelfth embodiment of the present technology, the "COLOR" field is provided in SIGNAL 311. If there is a reserved part in the SIGNAL field of the existing format, by storing the COLOR field in that part, the reception of the legacy device is not hindered, and in the twelfth embodiment of the present technology. A specific function can be realized. When defining a new SIGNAL field format, store COLOR information in that part.
An information processing device (other than a legacy device) that receives a packet having a COLOR field can acquire the contents of the COLOR field. Then, the information processing apparatus can change the applied detection threshold value and the reception operation based on the contents of the COLOR field.
[Connection processing example]
The connection process is the same as that of the first embodiment of the present technology.
[Operation example of physical header parameter determination processing]
FIG. 48 is a flowchart showing an example of the processing procedure of the physical header parameter determination processing by the information processing apparatus 200 in the twelfth embodiment of the present technology.
When the connection is established, the control unit of the information processing apparatus 200 creates physical header parameters (for example, each detection threshold value of the physical header) used by the subordinate terminal in the own BSS and the own device (if it already exists). Update to). The difference in the physical header in the twelfth embodiment of the present technology specifically means that the BSS identifier information (COLOR information) in the physical header matches that to which the own device belongs, or , Does not match, means the difference.
First, the control unit of the information processing apparatus 200 performs packet monitoring (step S841). Then, the control unit of the information processing apparatus 200 acquires each information regarding the communication quality with the information processing apparatus under each subordinate in the own BSS and the communication quality of the packet from another BSS (OBSS) (step S841).
Here, an example of using the correlated output strength of RSSI or PLCP preamble as an index of communication quality is shown. This correlated output strength shall indicate the absolute level of the correlated output multiplied by the received signal power strength (RSSI), rather than the power normalized correlator output itself. That is, the correlation output intensity means the correlator output corrected in terms of antenna input. Further, when the reception history in a relatively short time exists, the record of the correlation output intensity at that time may be diverted. In addition, the detection threshold value may be temporarily lowered so that samples can be collected more reliably during monitoring.
Subsequently, the control unit of the information processing device 200 classifies the communication quality of the received packet from each subordinate information processing device in the own BSS and the communication quality of the received packet from another BSS (OBSS) (step S842). ). Then, the control unit of the information processing apparatus 200 extracts the minimum correlation output strength related to its own BSS and the maximum correlation output strength related to OBSS (step S842).
Here, the minimum correlation output strength for the own BSS means the minimum correlation output strength of the packet whose BSS identifier (BSSID in the MAC header or BSS COLOR information in the physical header) is the same as the BSS to which the own device belongs. Let it be COL_self. The maximum correlation output strength for OBSS means the maximum correlation output strength of a packet whose BSS identifier (BSSID in the MAC header or BSS COLOR information in the physical header) is different from the BSS to which the own device belongs, and is COL_other.
COL that does not have a packet sample with the applicable conditions shall be replaced with PD_default. Here, PD_default represents the reference level for preamble detection used by the Legacy device, and the IEEE 802.11 standard refers to a value of -82 dBm per 20 MHz bandwidth as a guideline.
Subsequently, the control unit of the information processing apparatus 200 determines the detection threshold PD_self for the physical header indicating its own BSS and the detection threshold PD_other for the physical header indicating OBSS based on each extracted correlation output intensity (step). S843). For example, the detection threshold PD_self and the detection threshold PD_other can be determined within the range in which the following equations 16, 17, and 18 are established. The determination of PD_self may be omitted. In that case, use PD_default instead. PD_self <COL_self ... Equation 16 PD_other> COL_other ... Equation 17 PD_other <COL_self ... Equation 18 In this case, if there is no PD_other that satisfies Equation 17 and Equation 18 at the same time, Equation 18 takes precedence. To do.
Further, PD_other may be individually determined for each information processing device under its control. Let n be the index of the information processing device, and PD_other (n) be the PD_other that should be used by the nth subordinate information processing device. The control unit of the information processing device 200 classifies the packets transmitted from the information processing devices under each subordinate in the own BSS from the above-mentioned monitor results for each source. Assuming that the minimum correlation output intensities obtained from the packets from the nth subordinate information processing device are COL_self (n), PD_other (n) is determined so as to satisfy the following equation 19. PD_other (n) <COL_self (n) ... Equation 19 Even when setting individually, PD_other (n) does not necessarily have to be specified for all subordinate devices. In that case, the common PD_other information that should be used by the device that was not individually specified is additionally determined.
Here, an example of the carrier sense detection range of each information processing apparatus set based on the detection threshold PD_self and the detection threshold PD_other (n) is shown. Here, an example of the carrier sense detection ranges of the information processing devices 100, 102, 200, and 201 will be described with reference to FIGS. 12 and 13.
As described above, in FIG. 12, the carrier sense detection ranges 31 to 34 of the information processing devices 100 and 102 are schematically shown by dotted circles. Further, in FIG. 13, the carrier sense detection ranges 41 to 44 of the information processing devices 200 and 201 are schematically shown by dotted circles.
For example, in FIG. 12, the carrier sense detection range 31 corresponds to the carrier sense detection range of the information processing device 100 set based on the detection threshold PD_self for the physical header indicating the own BSS of the information processing device 100. Further, the carrier sense detection range 33 corresponds to the carrier sense detection range of the information processing device 100 set based on the detection threshold PD_other (n) for the physical header indicating the OBSS of the information processing device 100.
Further, in FIG. 12, the carrier sense detection range 32 indicates the carrier sense detection range of the information processing device 102 set based on the detection threshold PD_self for the physical header indicating the own BSS of the information processing device 102. Further, the carrier sense detection range 34 corresponds to the carrier sense detection range of the information processing device 102 set based on the detection threshold PD_other (n) for the physical header indicating the OBSS of the information processing device 102.
Further, in FIG. 13, the carrier sense detection range 41 corresponds to the carrier sense detection range of the information processing device 200 set based on the detection threshold PD_self for the physical header indicating the own BSS of the information processing device 200. Further, the carrier sense detection range 43 corresponds to the carrier sense detection range of the information processing device 200 set based on the detection threshold PD_other (n) for the physical header indicating the OBSS of the information processing device 200.
Further, in FIG. 13, the carrier sense detection range 42 indicates the carrier sense detection range of the information processing device 201 set based on the detection threshold PD_self for the physical header indicating the own BSS of the information processing device 201. Further, the carrier sense detection range 44 corresponds to the carrier sense detection range of the information processing device 201 set based on the detection threshold PD_other (n) for the physical header indicating the OBSS of the information processing device 201.
The monitor and the set value shown in FIG. 48 may be determined at regular intervals or every time a connection of a new subordinate device is detected so that the set value is sequentially updated.
[Example of sharing process of physical header parameters]
Further, the procedure and the first embodiment of the present technology are the same for the sharing process of the physical header parameters. However, in the twelfth embodiment of the present technology, the physical header parameter is the detection threshold value of each physical header (the detection threshold value PD_self of the physical header for own BSS and the detection threshold value PD_other of the physical header for OBSS). FIG. 49 shows an example of the frame format used in this case.
[Beacon frame format example]
FIG. 49 is a diagram showing an example of a beacon frame format exchanged between the devices constituting the communication system 10 according to the twelfth embodiment of the present technology. Since FIG. 49 is a modification of FIG. 14, a part of the description of the parts common to FIG. 14 will be omitted.
Figure 49 shows an example of adding new elements "Multi Detect Parameter" 391 and "COLOR Info" 392 to Payload 390.
The "Multi Detect Parameter" 391 is provided with three fields 393 to 395.
The Preamble Detection Threshold for Packets of This BSS393 stores the detection threshold PD_self of the physical header for the own BSS. Also, Preamble Detection Threshold for Packets of The detection threshold PD_other of the physical header for OBSS is stored in OBSS394. However, although it is necessary to store the detection threshold PD_other of the physical header for OBSS, the storage of the detection threshold of the physical header for own BSS can be omitted. In this way, when the storage of the detection threshold value of the physical header for own BSS is omitted, each information processing device can substitute PD_self = PD_default. In the above-mentioned physical header parameter determination process, when PD_other is individually determined for each subordinate information processing device (that is, when PD_other (n) is determined respectively), all the information of PD_other (n) is displayed in this field. Is stored with information that identifies the subordinate device to which it corresponds. If PD_other (n) is not specified for all subordinate devices, the PD_other information commonly used by unspecified devices is also stored.
The Allow No Color Filtering 395 stores information indicating whether or not to allow reception termination for packets that do not include BSS COLOR. Whether or not to allow the reception termination can be set according to, for example, the device connected to the information processing apparatus 200. For example, if there is no device (for example, a legacy device) that cannot add COLOR information under the information processing device 100, the control unit of the information processing device 200 may set to allow it. it can.
If the information stored in Allow No Color Filtering 395 can be substituted by another field, it may be substituted by another field. In this way, when substituting with another field, it is possible to omit the storage of the information to be stored in the Allow No Color Filtering 395 in the "Multi Detect Parameter".
"COLOR Info" 392 stores the BSS identifier in the physical layer. This BSS identifier corresponds to the BSS identifier stored in the "BSS COLOR" field shown in FIG.
For example, the control unit of the information processing device 200 transmits a beacon in which each information is stored in "Multi Detect Parameter" 391 and "COLOR Info" 392 to a surrounding information processing device to notify the information.
The information processing apparatus that has received the notification by the beacon acquires and holds each information stored in the "Multi Detect Parameter" 391 and the "COLOR Info" 392 from the beacon. That is, the information processing device holds the contents of the "Multi Detect Parameter" and the BSS identifier in the physical layer. Here, when PD_other to be used by the information processing device is individually specified, PD_other (n) corresponding to the own device is retained as the value of PD_other. If not specified individually, the subordinate device holds the value of PD_other that should be used in common.
If the information contained in the subsequent beacon changes after the content of the beacon is retained, the information contained in the latest beacon (latest information) is adopted and retained.
Further, the master station may notify the contents of the "Multi Detect Parameter" and the BSS identifier at the physical layer by using a signal other than the beacon transmission. For example, the master station may notify the subordinate terminal in a unicast data frame or a management frame by using a judgment by its own device or an information acquisition request from the subordinate terminal as a trigger.
[Example of physical header determination process]
In the twelfth embodiment of the present technology, the BSS COLOR information used in the own BSS is added to the physical header. Also, the PLCP header is not changed according to the link status. The physical header used determination process is similarly performed for both the uplink and the downlink.
[Send / receive processing example]
The transmission / reception processing in the twelfth embodiment of the present technology is the same as that in the ninth embodiment of the present technology (transmission / reception processing shown in FIG. 37). For example, both the master station side and the slave station side can be equivalent to the transmission / reception processing shown in FIG. 37. For example, it is assumed that both the master station side and the slave station side basically perform packet detection / reception determination processing during times other than transmission and reception.
[Operation example of packet detection / reception judgment processing]
The packet detection / reception determination process in the twelfth embodiment of the present technology is basically the same as that in the ninth embodiment of the present technology (operation example shown in FIG. 39). However, the processing classification table to be referenced is different.
FIG. 50 is a diagram showing an example (processing classification table) of the relationship between the processing performed by the information processing apparatus 100 and the physical header in the twelfth embodiment of the present technology. Note that FIG. 50 will be described in detail with reference to FIG. 39.
As shown in FIG. 39, each of the master station and the slave station corresponding to each function in the twelfth embodiment of the present technology receives RSSI for a signal input through the antenna while in the standby state. And monitor the correlator output (step S801).
Subsequently, the control unit 150 of the information processing apparatus 100 performs the correlation calculation of the Preamble pattern, and compares the output (correlator output) with the provisional detection threshold value (step S802). Here, the provisional detection threshold is a detection threshold for reading the SINGAL field prior to the main determination process. As the provisional detection threshold, for example, a value that is equal to or less than both PD_self and PD_other can be used. Further, for example, PD_default may be used as the provisional detection threshold value.
Further, the correlator output referred to here means the above-mentioned correlation output intensity COL, and is not a normalized correlator output level but a correlator output converted by reflecting the received power. ..
When the value of the correlator output exceeds the provisional detection threshold value (step S802), the control unit 150 of the information processing apparatus 100 determines that it is in the provisional detection state and transitions to the carrier sense BUSY state (step). S806). Subsequently, the control unit 150 of the information processing apparatus 100 decodes the subsequent SIGNAL field in the physical header and reads out the information and the like in the SIGNAL field (step S807). Specifically, each of the "COLOR" field and the CRC of the physical header is read.
Further, the control unit 150 of the information processing apparatus 100 collates each read information with the processing classification table shown in FIG. 50, and determines the subsequent processing (step S807).
Specifically, the control unit 150 of the information processing apparatus 100 calculates the CRC of the physical header and confirms the presence or absence of an error in the physical header. Here, if there is an error in the physical header, the validity of the field value cannot be confirmed. Therefore, as shown in FIG. 50, when there is an error in the physical header, the subsequent processing is determined as "reception termination (ERROR)". If there is no error in the CRC of the physical header, the process is determined based on the contents of the "COLOR" field and each information shared in the physical header parameter sharing process.
Specifically, when the COLOR information in the physical header matches the COLOR information of the own BSS, the subsequent processing is determined to be "received".
When the COLOR information in the physical header is different from the COLOR information of the own BSS, the control unit 150 of the information processing apparatus 100 compares the determined detection threshold value with the value of the correlator output.
When the COLOR information in the physical header is different from the COLOR information of the own BSS and the value of the correlator output is low based on the detection threshold PD_other for the physical header indicating OBSS, the subsequent processing is "discontinued". (IDLE) ".
If the COLOR information in the physical header is different from the COLOR information of the own BSS and the value of the correlator output is high based on the detection threshold PD_other for the physical header indicating OBSS, the subsequent processing is performed as " Receiving cutoff (BUSY) ".
When the value of the correlator output is low with respect to the detection threshold PD_other, it means that the value of the correlator output is equal to or less than the detection threshold PD_other or less than the detection threshold PD_other. When the value of the correlator output is high with respect to the detection threshold PD_other, it means that the value of the correlator output is equal to or greater than the detection threshold PD_other or exceeds the detection threshold PD_other. However, when the value of the correlator output is low based on the detection threshold PD_other, when the value of the correlator output is equal to or less than the detection threshold PD_other, the value of the correlator output is high based on the detection threshold PD_other. It is assumed that the output value exceeds the detection threshold PD_other. Similarly, when the value of the correlator output is low with respect to the detection threshold PD_other, and when the value of the correlator output is less than the detection threshold PD_other, the value of the correlator output is high with respect to the detection threshold PD_other. It is assumed that the value of the device output is equal to or higher than the detection threshold PD_other.
If there is no COLOR information in the physical header, the subsequent processing is basically "received". However, as an exception, only when reception termination of packets that do not include COLOR information is permitted in BSS, the same judgment as in the case of COLOR mismatch described above is made. Whether or not this permission is permitted can be determined based on the information stored in Allow No COLOR Filtering 395 shown in FIG.
Since each process other than this is the same as that of the ninth embodiment of the present technology, the description thereof is omitted here.
As described above, for example, the preamble correlator output level of the received packet in terms of antenna input is lower than the packet detection threshold derived from the information described in the physical header of the packet. 1 condition can be met. In this case, the control unit 150 can derive the value by the conversion based on the value described in the physical header of the packet and the information about the quantization and the unit shared in advance.
In the embodiment of the present technology, the communication system including the access points (information processing devices 200 and 201) has been described as an example, but the embodiment of the present technology is also applied to the communication system not including the access point. be able to. Communication systems that do not include access points are, for example, mesh networks and ad hoc networks.
Also, for example, when checking the quality of a link with another information processing device that is not connected to the own device, the packet detection condition (PLCP detection) where the condition is most relaxed during the time when the response is expected Threshold) may be used.
Here, in the CSMACA network, when the number of slave stations increases, in the carrier sense method, excessive transmission suppression may occur and the transmission efficiency of the entire system may decrease. Therefore, there is a method of increasing the transmission opportunity by increasing the carrier sense detection threshold. However, even if the transmission opportunity of the transmission side increases, if the receiving terminal receives an irrelevant packet first, it will be received. You lose the opportunity. Therefore, it is necessary for the receiving side to appropriately raise the detection threshold.
However, it is assumed that it is difficult to optimally set the detection threshold value in advance for an information processing device (for example, an access point) in which a plurality of connection partners that transmit asynchronously to the own device exist at the same time. For example, if the threshold value is constantly increased, the service area becomes narrow and there is a possibility that it is not possible to properly communicate with a part of a plurality of connection partners.
Therefore, in the embodiment of the present technology, a plurality of physical headers to be used properly according to the attenuation with the destination are defined, and different detection threshold values corresponding to each are prepared. As a result, the detection operation can be appropriately changed according to the communication partner. That is, according to the embodiment of the present technology, it is possible to avoid excessive transmission suppression as necessary, increase both transmission opportunities and reception opportunities, and improve the utilization efficiency of wireless resources. In other words, wireless resources can be efficiently used for channel access in wireless transmission.
<13. Application example> The technology according to the present disclosure can be applied to various products. For example, the information processing devices 100 to 104, 200, 201 include smartphones, tablet PCs (Personal Computers), notebook PCs, mobile terminals such as portable game terminals or digital cameras, television receivers, printers, digital scanners, or network storage. It may be realized as a fixed terminal such as, or an in-vehicle terminal such as a car navigation device. In addition, the information processing devices 100 to 104, 200, and 201 are terminals (MTC (MAChine Type)) that perform M2M (MAChine To MAChine) communication, such as smart meters, vending machines, remote monitoring devices, and POS (Point Of Sale) terminals. It may be realized as (Communication) terminal). Further, the information processing devices 100 to 104, 200, and 201 may be wireless communication modules (for example, integrated circuit modules composed of one die) mounted on these terminals.
On the other hand, for example, the information processing devices 200 and 201 may be realized as a wireless LAN access point (also referred to as a wireless base station) having a router function or not having a router function. Further, the information processing devices 200 and 201 may be realized as a mobile wireless LAN router. Further, the information processing devices 200 and 201 may be wireless communication modules (for example, integrated circuit modules composed of one die) mounted on these devices.
[13-1. First application example]
FIG. 51 is a block diagram showing an example of a schematic configuration of a smartphone 900 to which the technology according to the present disclosure can be applied. The smartphone 900 includes a processor 901, a memory 902, a storage 903, an external connection interface 904, a camera 906, a sensor 907, a microphone 908, an input device 909, a display device 910, a speaker 911, a wireless communication interface 913, an antenna switch 914, and an antenna 915. It is equipped with a bus 917, a battery 918 and an auxiliary controller 919.
The processor 901 may be, for example, a CPU (Central Processing Unit) or an SoC (System on Chip), and controls the functions of the application layer and other layers of the smartphone 900. The memory 902 includes a RAM (RandoM Access Memory) and a ROM (Read Only Memory), and stores programs and data executed by the processor 901. The storage 903 may include a storage medium such as a semiconductor memory or a hard disk. The external connection interface 904 is an interface for connecting an external device such as a memory card or a USB (Universal Serial Bus) device to the smartphone 900.
The camera 906 has an image pickup device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), and generates an captured image. The sensor 907 may include, for example, a group of sensors such as a positioning sensor, a gyro sensor, a geomagnetic sensor and an acceleration sensor. The microphone 908 converts the voice input to the smartphone 900 into a voice signal. The input device 909 includes, for example, a touch sensor, a keypad, a keyboard, a button, or a switch that detects a touch on the screen of the display device 910, and receives an operation or information input from the user. The display device 910 has a screen such as a liquid crystal display (LCD) or an organic light emitting diode (OLED) display, and displays an output image of the smartphone 900. The speaker 911 converts the voice signal output from the smartphone 900 into voice.
The wireless communication interface 913 supports one or more of the wireless LAN standards such as IEEE802.11a, 11b, 11g, 11n, 11ac and 11ad to perform wireless communication. The wireless communication interface 913 can communicate with other devices via the wireless LAN access point in the infrastructure mode. Further, the wireless communication interface 913 can directly communicate with other devices in the ad hoc mode or the direct communication mode such as Wi-Fi Direct. In Wi-Fi Direct, unlike the ad hoc mode, one of the two terminals operates as an access point, but communication is performed directly between those terminals. The wireless communication interface 913 is typically a baseband processor, RF (Radio). Frequency) can include circuits and power amplifiers. The wireless communication interface 913 may be a one-chip module in which a memory for storing a communication control program, a processor for executing the program, and related circuits are integrated. In addition to the wireless LAN system, the wireless communication interface 913 may support other types of wireless communication systems such as a short-range wireless communication system, a proximity wireless communication system, or a cellular communication system. The antenna switch 914 switches the connection destination of the antenna 915 among a plurality of circuits (for example, circuits for different wireless communication methods) included in the wireless communication interface 913. The antenna 915 has a single antenna element or a plurality of antenna elements (for example, a plurality of antenna elements constituting a MIMO antenna), and is used for transmitting and receiving a radio signal by the radio communication interface 913.
Not limited to the example of FIG. 51, the smartphone 900 may be provided with a plurality of antennas (for example, an antenna for a wireless LAN and an antenna for a proximity wireless communication method). In that case, the antenna switch 914 may be omitted from the configuration of the smartphone 900.
Bus 917 connects processor 901, memory 902, storage 903, external connection interface 904, camera 906, sensor 907, microphone 908, input device 909, display device 910, speaker 911, wireless communication interface 913 and auxiliary controller 919 to each other. .. The battery 918 supplies power to each block of the smartphone 900 shown in FIG. 51 via a power supply line partially shown by a broken line in the figure. The auxiliary controller 919 operates the minimum necessary functions of the smartphone 900, for example, in the sleep mode.
In the smartphone 900 shown in FIG. 51, the control unit 150 described with reference to FIG. 5 may be implemented in the wireless communication interface 913. Also, at least some of these features may be implemented in processor 901 or auxiliary controller 919. For example, the efficient use of wireless resources by grouping can reduce the power consumption of the battery 918.
The smartphone 900 may operate as a wireless access point (software AP) when the processor 901 executes an access point function at the application level. Further, the wireless communication interface 913 may have a wireless access point function.
[13-2. Second application example]
FIG. 52 is a block diagram showing an example of a schematic configuration of a car navigation device 920 to which the technique according to the present disclosure can be applied. The car navigation device 920 includes a processor 921, a memory 922, a GPS (Global Positioning System) module 924, a sensor 925, a data interface 926, a content player 927, a storage medium interface 928, an input device 929, a display device 930, a speaker 931 and wireless communication. It has an interface 933, an antenna switch 934, an antenna 935 and a battery 938.
The processor 921 may be, for example, a CPU or SoC, and controls the navigation function and other functions of the car navigation device 920. The memory 922 includes RAM and ROM and stores programs and data executed by the processor 921.
The GPS module 924 uses GPS signals received from GPS satellites to measure the position (eg, latitude, longitude and altitude) of the car navigation device 920. The sensor 925 may include, for example, a group of sensors such as a gyro sensor, a geomagnetic sensor and a barometric pressure sensor. The data interface 926 is connected to the vehicle-mounted network 941 via a terminal (not shown), and acquires data generated on the vehicle side such as vehicle speed data.
The content player 927 plays content stored on a storage medium (eg, a CD or DVD) inserted into the storage medium interface 928. The input device 929 includes, for example, a touch sensor, a button, or a switch that detects a touch on the screen of the display device 930, and receives an operation or information input from the user. The display device 930 has a screen such as an LCD or OLED display and displays an image of a navigation function or a content to be played. The speaker 931 outputs the sound of the navigation function or the content to be played.
The wireless communication interface 933 supports one or more of the wireless LAN standards such as IEEE802.11a, 11b, 11g, 11n, 11ac and 11ad to perform wireless communication. The wireless communication interface 933 can communicate with other devices via the wireless LAN access point in the infrastructure mode. In addition, the wireless communication interface 933 is in ad hoc mode or Wi-Fi. In a direct communication mode such as Direct, it is possible to communicate directly with another device. The wireless communication interface 933 may typically include a baseband processor, an RF circuit, a power amplifier, and the like. The wireless communication interface 933 may be a one-chip module in which a memory for storing a communication control program, a processor for executing the program, and related circuits are integrated. In addition to the wireless LAN system, the wireless communication interface 933 may support other types of wireless communication systems such as a short-range wireless communication system, a proximity wireless communication system, or a cellular communication system. The antenna switch 934 switches the connection destination of the antenna 935 between a plurality of circuits included in the wireless communication interface 933. The antenna 935 has a single or multiple antenna elements and is used for transmitting and receiving radio signals by the wireless communication interface 933.
Not limited to the example of FIG. 52, the car navigation device 920 may include a plurality of antennas. In that case, the antenna switch 934 may be omitted from the configuration of the car navigation device 920.
The battery 938 supplies electric power to each block of the car navigation device 920 shown in FIG. 52 via a power supply line partially shown by a broken line in the figure. In addition, the battery 938 stores electric power supplied from the vehicle side.
In the car navigation device 920 shown in FIG. 52, the control unit 150 described with reference to FIG. 5 may be implemented in the wireless communication interface 933. Also, at least some of these features may be implemented in processor 921.
Further, the wireless communication interface 933 may operate as the above-mentioned information processing device 100 and provide a wireless connection to a terminal owned by a user in a vehicle.
Further, the technique according to the present disclosure may be realized as an in-vehicle system (or vehicle) 940 including one or more blocks of the car navigation device 920 described above, an in-vehicle network 941, and a vehicle-side module 942. The vehicle-side module 942 generates vehicle-side data such as vehicle speed, engine speed, or failure information, and outputs the generated data to the vehicle-mounted network 941.
[13-3. Third application example]
FIG. 53 is a block diagram showing an example of a schematic configuration of a wireless access point 950 to which the technique according to the present disclosure can be applied. The wireless access point 950 includes a controller 951, a memory 952, an input device 954, a display device 955, a network interface 957, a wireless communication interface 963, an antenna switch 964, and an antenna 965.
The controller 951 may be, for example, a CPU or DSP (Digital SIGNAL Processor), and various functions (for example, access restriction, routing, encryption, firewall) of the IP (Internet Protocol) layer and higher layers of the wireless access point 950. And log management, etc.) are operated. The memory 952 includes RAM and ROM, and stores a program executed by the controller 951 and various control data (for example, a terminal list, a routing table, an encryption key, a security setting, and a log).
The input device 954 includes, for example, a button or a switch, and receives an operation from the user. The display device 955 includes an LED lamp and the like to display the operating status of the wireless access point 950.
The network interface 957 is a wired communication interface for the wireless access point 950 to connect to the wired communication network 958. The network interface 957 may have a plurality of connection terminals. The wired communication network 958 may be a LAN such as Ethernet (registered trademark) or a WAN (Wide Area Network).
The wireless communication interface 963 supports one or more of the wireless LAN standards such as IEEE802.11a, 11b, 11g, 11n, 11ac and 11ad, and provides a wireless connection as an access point to nearby terminals. The wireless communication interface 963 may typically include a baseband processor, RF circuits, power amplifiers, and the like. The wireless communication interface 963 may be a one-chip module in which a memory for storing a communication control program, a processor for executing the program, and related circuits are integrated. The antenna switch 964 switches the connection destination of the antenna 965 among a plurality of circuits included in the wireless communication interface 963. The antenna 965 has a single or multiple antenna elements and is used for transmitting and receiving radio signals by the radio communication interface 963.
In the wireless access point 950 shown in FIG. 53, the control unit 150 described with reference to FIG. 5 may be implemented in the wireless communication interface 963. Also, at least some of these features may be implemented in controller 951.
The above-described embodiment shows an example for embodying the present technology, and the matters in the embodiment and the matters specifying the invention in the claims have a corresponding relationship with each other. Similarly, the matters specifying the invention in the claims and the matters in the embodiment of the present technology having the same name have a corresponding relationship with each other. However, the present technology is not limited to the embodiment, and can be embodied by applying various modifications to the embodiment without departing from the gist thereof.
Further, the processing procedure described in the above-described embodiment may be regarded as a method having these series of procedures, and as a program for causing a computer to execute these series of procedures or as a recording medium for storing the program. You may catch it. As this recording medium, for example, a CD (Compact Disc), MD (Mini Disc), DVD (Digital Versatile Disc), memory card, Blu-ray Disc (Blu-ray (registered trademark) Disc) and the like can be used.
It should be noted that the effects described in the present specification are merely examples and are not limited, and other effects may be obtained.
The present technology can have the following configurations. (1) Packet reception is terminated in the middle according to the first condition, and the time from the start of packet reception to the termination of packet reception is operated as if the carrier sense was idle according to the second condition. An information processing device including a control unit that performs control. (2) Described in (1) above, the control unit controls so as not to generate a waiting time corresponding to IFS (Inter Frame Space) when the second condition is satisfied after the reception of the packet is terminated. Information processing equipment. (3) When the second condition is satisfied after the reception of the packet is terminated, the control unit slots the time length from the time when the carrier sense transitions to BUSY to the reception termination time at the time of receiving the packet. The information processing apparatus according to (1) or (2) above, which controls conversion to time and subtraction from the backoff counter. (4) The information processing apparatus according to (3) above, wherein the control unit treats the result as 0 when the result after the subtraction becomes a negative value. (Five) When the result after the subtraction becomes a negative value, the control unit sets the negative value as a positively folded value so as not to exceed the backoff counter before the subtraction (3). ). Information processing device. (6) From the above (1), the first condition includes that the CRC calculation result for the physical header portion in the packet being received does not match the CRC information described in the physical header. The information processing device according to any one of (5). (7) The first condition is that when the information about the identifier for identifying the network is present in the physical header in the packet, the information about the identifier is different from the network identifier of the network to which the information processing apparatus belongs. The information processing apparatus according to (6) above, further including. (8) The first condition is that the preamble correlator output level of the packet being received in terms of antenna input is lower than the threshold value derived from the information described in the physical header of the packet. The information processing apparatus according to (6) above, further including. (9) When the information regarding the identifier for identifying the network exists in the physical header of the packet and the information regarding the identifier matches the network identifier of the network to which the information processing apparatus belongs, the control unit terminates reception. The information processing apparatus according to (8) above, which continues without any problems. (10) The information processing device according to (8) above, wherein the control unit performs the derivation based on the association between the index described in the physical header of the packet and the table of threshold values shared in advance. (11) The information processing according to (8) above, wherein the control unit performs the derivation by conversion based on the value described in the physical header of the packet and the information regarding the quantization and the unit shared in advance. apparatus. (12) The information processing apparatus according to (1) above, wherein the second condition includes the first condition. (13) The control unit determines whether or not the operation is necessary under the second condition that the received power of the packet being received falls below a predetermined energy detection threshold (1) to (10). The information processing device according to any one of. (14) The control unit determines whether or not the operation is necessary, subject to the second condition that transmission suppression by virtual carrier sense is not applied at the time when reception of the packet is cut off, according to the above (1) to (10). The information processing device according to any one. (15) In the control unit, the CRC calculation result for the physical header unit in the packet does not match the CRC information described in the physical header, and the packet is converted into an antenna input. One of the above (1) to (10) for determining the necessity of the operation, subject to the second condition that the preamble correlator output level is lower than the minimum applicable packet detection threshold. The information processing device described. (16) The control unit performs control to prohibit transmission from the information processing apparatus during the duration of the packet transfer when the second condition is not satisfied after the reception of the packet is terminated (1). The information processing device according to any one of (15). (17) When the control unit does not satisfy the second condition after the reception of the packet is terminated and transmission from the information processing device is prohibited during the duration of the packet transfer, the control unit is addressed to the information processing device and is addressed to the information processing device. The information processing apparatus according to (16) above, which controls transmission of a response to the frame when a frame requesting a response is received. (18) Assuming that the carrier sense is idle for the first step in which packet reception is interrupted according to the first condition and the time from the start of packet reception to the termination of packet reception according to the second condition. An information processing method that includes a second step that works. (19) Assuming that the carrier sense is idle for the first step in which packet reception is interrupted according to the first condition and the time from the start of packet reception to the termination of packet reception according to the second condition. A program that causes a computer to perform a second step that works.
10, 50 Communication system 100 to 104, 200, 201 Information processing device 110 Data processing unit 120 Transmission processing unit 130 Modulation / demodulation unit 140 Wireless interface unit 141 Antenna 150 Control unit 160 Memory 900 Smartphone 901 Processor 902 Memory 903 Storage 904 External connection interface 906 Camera 907 Sensor 908 Microphone 909 Input device 910 Display device 911 Speaker 913 Wireless communication interface 914 Antenna switch 915 Antenna 917 Bus 918 Battery 919 Auxiliary controller 920 Car navigation device 921 Processor 922 Memory 924 GPS module 925 Sensor 926 Data interface 927 Content player 928 Memory Media Interface 929 Input Device 930 Display Device 931 Speaker 933 Wireless Communication Interface 934 Antenna Switch 935 Antenna 938 Battery 941 Automotive Network 942 Vehicle Side Module 950 Wireless Access Point 951 Controller 952 Memory 954 Input Device 955 Display Device 957 Network Interface 958 Wired Communication Network 963 Wireless Communication Interface 964 Antenna Switch 965 Antenna
53 sheets
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Every citation, both ways
| Document | Relation | Office |
|---|---|---|
| JP06029981A | Cites | Japan |
| JP2004207921A | Cites | Japan |
| JP2001144671A | Cites | Japan |
| JP2008042383A | Cites | Japan |
| US20110014910A1 | Cites | United States of America |
29 members in 11 offices
Priority claims19
| Document | Office | Kind | Date |
|---|---|---|---|
| 2014142950 | Japan | A | |
| 2014142950 | Japan | A | |
| 2014142950 | Japan | – | |
| 2015002478 | Japan | A | |
| 2015002478 | Japan | A | |
| 2015002478 | Japan | – | |
| 2015002479 | Japan | A | |
| 2015002479 | Japan | A | |
| 2015002479 | Japan | – | |
| 2015063346 | Japan | W | |
| 2015063346 | Japan | W | |
| 2014142950 | – | – | – |
| 2015002478 | – | – | – |
| 2015002479 | – | – | – |
| JP20140142950 | – | – | – |
| JP20150002478 | – | – | – |
| JP20150002479 | – | – | – |
| JP2015063346 | – | – | – |
| WO2015JP63346 | – | – | – |
Members29
| Document | Office | Kind | |
|---|---|---|---|
| CA2953541A1 | Canada | A1 | |
| WO2016006311A1 | World Intellectual Property Organization (WIPO) | A1 | |
| WO2016006312A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU2015286420A1 | Australia | A1 | |
| KR20170028894A | Republic of Korea | A | |
| CN106576370A | China | A | |
| PH12016502587A1 | Philippines | A1 | |
| JPWO2016006312A1 | Japan | A1 | |
| CN106664721A | China | A | |
| EP3169132A1 | European Patent Office (EPO) | A1 | |
| EP3169133A1 | European Patent Office (EPO) | A1 | |
| JPWO2016006311A1 | Japan | A1 | |
| US2017171888A1 | United States of America | A1 | |
| US2017202016A1 | United States of America | A1 | |
| BR112017000106A2 | Brazil | A2 | |
| EP3169133A4 | European Patent Office (EPO) | A4 | |
| EP3169132A4 | European Patent Office (EPO) | A4 | |
| AU2015286420B2 | Australia | B2 | |
| JP6465112B2This record | Japan | B2 | |
| JP6536577B2 | Japan | B2 | |
| US10362601B2 | United States of America | B2 | |
| CN106664721B | China | B | |
| US10667293B2 | United States of America | B2 | |
| MY178987A | Malaysia | A | |
| CN106576370B | China | B | |
| EP3169133B1 | European Patent Office (EPO) | B1 | |
| KR102344656B1 | Republic of Korea | B1 | |
| CA2953541C | Canada | C | |
| EP3169132B1 | European Patent Office (EPO) | B1 |
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Numbers
- Publication
- 6465112
- Publication, DOCDB
- 6465112
- Publication, EPODOC
- JP6465112B
- Application
- 2016532475
- Application, DOCDB
- 2016532475
- Application, EPODOC
- JP20160532475
Titles2
- Japanese
- 情報処理装置、情報処理方法およびプログラム
- English
- Information processing equipment, information processing methods and programs
Classification
- CPC, 8
- H04W74/0808
- H04W74/08
- H04B1/16
- H04W84/12
- H04L67/10
- H04W72/0446
- H04L69/22
- H04W74/0816
- IPC, 3
- H04W74 08
- H04B1 16
- H04W84 18
