Access method and apparatus

Access methods and devices

The present invention relates to the field of wireless communication technology, and more particularly to an access method and apparatus.

To solve the WLAN Quality of Service (QoS) problem, the Institute of Electrical and Electronics Engineers (IEEE) introduced the IEEE802.11e standard.

IEEE802.11e extends the Distributed Coordination Function (DCF) channel access mechanism in the Media Access Control (MAC) layer of the existing IEEE802.11 to provide Enhanced Distributed Channel Access (EDCA). to form EDCA enhances the DCF mechanism, distinguishes the priorities of different service applications, ensures the channel access function of the high-priority service, and guarantees the bandwidth of the high-priority service to some extent.

The 802.11e protocol has four access categories (Access) including Background traffic (AC_BK), Best Effort traffic (AC_BE), Video traffic (AC_VI) and Audio traffic (AC_VO). There is a Category, AC) queue, and various EDCA parameters can be configured so that an AC queue with a higher priority has more transmission opportunities and less latency. In the protocol, an access category index (ACI) is used to identify the aforementioned access category. The queue is selected according to the priority included in the data frame to ensure QoS in the wireless local area network environment.

An access point (AP) may add information about EDCA parameters set in a beacon frame, a probe response frame, an association response frame or a re-association response frame, and the parameter set is AIFSN, ACM , ACI, ECWmin, ECWmax, and other access categories (Access Category) including TXOP Limit represents the parameters of the EDCA channel access method.

The larger the value of the Arbitration Inter Frame Spacing Number (AIFSN), the longer the idle waiting time of the user.

Exponent form of CWmin (ECWmin) and Exponent form of CWmax (ECWmax) of CWmin determine the average backoff time value, and the larger the value of both parameters, the greater the average backoff time of the user. indicates that it is long.

TXOP Limit (Transmission Opportunity Limit) represents the maximum duration for which a user can occupy a channel after one successful competition. A larger TXOP Limit value indicates a longer duration for a user to occupy a channel once. A value of 0 means that only one packet can be sent each time after the channel is used, and the channel must be re-contented to resend packets.

Mandatory Admission Control (ACM) indicates whether an access category requires admission control. If the bit is 0, no admission control is required for that access category. If the bit is 1, admission control needs to be used before the access parameter of the access category is used for transmission.

In current applications, the four EDCA parameter sets are basically configured to individually correspond to different queues, and each parameter set has an effect on the overall Basic Service Set (BSS). That is, in the BSS, QoS characteristics of all STAs are consistent, and when two STAs transmit data in the same queue, the STAs use the same EDCA parameters.

In the existing application, since the STA can perform random access based on the time domain only on the main channel, the random access efficiency is relatively low. In uplink multi-user transmission, multiple stations can perform parallel random access on multiple channels at the same time to improve random access efficiency. However, in this access method, it is necessary to configure multi-user transmission after the AP successfully acquires the channel through contention, and it is necessary to increase the probability that the AP successfully acquires the channel through contention.

An embodiment of the present invention provides an access method and apparatus to enable multiple stations to perform parallel random access on multiple channels at the same time as possible and to improve random access efficiency. In order to achieve the above object, the following technical solutions are used in the embodiments of the present invention.

According to a first aspect, an embodiment of the present invention provides an access method, the access method comprising:

transmitting a first frame carrying uplink transmission requirement information to the access point; and

When the second frame carrying information about the uplink transmission resource is received from the access point within the agreed period, transmit uplink multi-user transmission data to the access point, or - the uplink multi-user transmission data is the uplink transmission resource Sent on - ; or if the second frame is not received within the agreed period, the station accessing the channel in a contention access scheme based on carrier sensing CSMA/CA.

includes

With reference to the first aspect, in a first implementation of the first aspect, the access method comprises:

receiving a radio frame received by the access point;

further comprising,

The radio frame indicates a transmission time of the second frame, and the radio frame is an association response frame, a beacon frame, or a response frame of the access point to a received data frame. In addition, the agreed period may be obtained according to the transmission time of the second frame.

According to a second aspect, an embodiment of the present invention provides an access method, the access method comprising:

Receiving a radio frame transmitted by the access point, wherein the radio frame indicates an access method for performing channel access, and the radio frame is an association response frame, a beacon frame, or a response of the AP to a received data frame frame); and

When a second frame (eg, a trigger frame) carrying information about an uplink transmission resource is received from the AP within an agreed period, transmitting uplink multi-user data to the AP, wherein the uplink multi-user data is transmitted on the uplink transmission resource, or if the second frame is not received within the agreed period, the station accessing the channel in a CSMA-CA based contention access scheme;

includes

With reference to the second aspect, in a first implementation of the second aspect, the access method includes: a contention access method based on Carrier Sense Multiple Access with Collision Avoidance (abbreviated as CSMA/CA); and at least one of a contention access scheme based on orthogonal frequency division multiple access (OFDMA for short) or an OFDMA-based scheduling access scheme.

With reference to the second aspect or the second implementation of the second aspect, in a third implementation of the second aspect, the second frame or radio frame further includes indication information indicating the following, or the following is agreed in advance in the protocol:

When the data frame carries the buffer status report BSR or when the data frame does not contain an undivided data frame, the data frame is transmitted in OFDMA contention access scheme.

According to a third aspect, an embodiment of the present invention provides an access method, the access method comprising:

Receiving a first frame carrying information about an uplink transmission resource from the AP;

Transmitting a second frame carrying uplink transmission requirement information to the AP, disabling a CSMA-CA based contention access scheme, or stopping a CSMA-CA based contention backoff timer corresponding to an uplink transmission requirement information queue step; and

If the third frame carrying information about the uplink transmission resource is received from the AP within the agreed period, send uplink multi-user transmission data to the AP, or - the uplink multi-user transmission data is transmitted on the uplink transmission resource - ; or if the third frame is not received within the agreed period, the station accessing the channel by enabling the CSMA-CA based contention access scheme.

includes

When there are many connected stations, a large number of stations may participate in CSMA/CA contention and OFDMA contention. Consequently, the probability of collision between stations is greatly increased and channel utilization is low. Therefore, according to the access method provided in this embodiment of the present invention, the channel access method can be managed, the congestion level of the system can be reduced, and the channel utilization can be increased.

Optionally, in this embodiment of the present invention, the agreed period may be counted using a timer, the initial value of the timer being specified by the access point or agreed upon in the protocol. In addition, if the channel in which the uplink transmission resource is located is in an idle state, the value of the timer gradually decreases with time, or if the channel is in use, the gradual decrease in the value of the timer is stopped. In addition, the value of the timer is updated when a channel is busy, a trigger frame carrying information about an uplink transmission resource is received, a trigger frame for random access is received, or a trigger frame carrying a training sequence is received, The method of updating the value of the timer is to add a constant to the current value of the timer or to multiply the constant.

Optionally, the uplink transmission requirement information includes at least one of the following: packet arrival interval, packet size information, or traffic rate information.

Corresponding to the method provided above, the embodiment of the present invention further provides a corresponding method on the access point side.

According to a fourth aspect, an embodiment of the present invention provides an access method, the method comprising:

receiving from the station a first frame carrying uplink transmission requirement information;

transmitting a second frame carrying information about an uplink transmission resource to the station; and

receiving uplink multi-user transmission data from the station, the uplink multi-user transmission data being transmitted on an uplink transmission resource;

includes

According to a fifth aspect, an embodiment of the present invention provides an access method, the access method comprising:

transmitting a radio frame to the station, the radio frame indicating an access method for performing channel access (e.g., whether to use an OFDMA-based access method or to disable a CSMA/CA-based contention access method), , the radio frame is an association response frame, a beacon frame, or an access point's response frame to a received data frame;

transmitting a second frame carrying information about an uplink transmission resource to the station; and

receiving uplink multi-user transmission data from a station, the uplink multi-user transmission data being transmitted on an uplink transmission resource;

includes

In the fifth aspect, the access point may indicate an access method for performing channel access according to scenario information using a radio frame. For example, in a centralized deployment (coverage areas of many stations or access points overlap heavily) scenario, the access point may instruct the station to disable the CSMA/CA based contention access scheme. The access point may instruct the station to use an OFDMA-based contention access scheme. The contention collision between stations can be reduced and the throughput ratio of the overall system can be improved. Otherwise, in a scenario where there are few stations, the access point may instruct the station to enable a CSMA/CA based contention access scheme. The access point controls the access method of the station and system resources can be used efficiently.

According to a sixth aspect, an embodiment of the present invention provides an access method, the method comprising:

transmitting a first frame carrying information about an uplink transmission resource to a station;

receiving from the station a second frame carrying uplink transmission requirement information;

transmitting a third frame (eg, a trigger frame) carrying information about an uplink transmission resource to the station; and

receiving uplink multi-user transmission data from a station, the uplink multi-user transmission data being transmitted on an uplink transmission resource;

includes

In a sixth aspect, the information about the uplink transmission resource in the third frame may further include identifiers of one or more stations using the uplink transmission resource.

Corresponding to the method provided above, an embodiment of the present invention further provides a corresponding apparatus.

According to a seventh aspect, an embodiment of the present invention provides an access device, the access device comprising:

a transmitting module, configured to transmit a first frame carrying uplink transmission requirement information to the access point; and

When the second frame carrying information about the uplink transmission resource is received from the access point within an agreed period, it transmits multi-user transmission data to the access point, or wherein the multi-user transmission data is transmitted on the uplink transmission resource. ; or if the second frame is not received within the agreed period, the processing module, configured to allow the station to access the channel in a contention access scheme based on carrier-sensing CSMA/CA

includes

According to an eighth aspect, an embodiment of the present invention provides an access device, the access device comprising:

a receiving module, configured to receive, from the station, a first frame carrying uplink transmission requirement information; and

a transmitting module, configured to transmit a second frame carrying information about an uplink transmission resource to the station

includes,

The receiving module is further configured to receive uplink multi-user transmission data from the station, wherein the uplink multi-user transmission data is transmitted on an uplink transmission resource.

the transmitting module is further configured to transmit a second frame to the one or more stations, wherein the second frame indicates one or more stations performing uplink multi-user transmission, wherein the one or more stations transmit the first frame including stations that

Hereinafter, some devices corresponding to the method are provided by using only the station side as an example. The device on the access point side may be provided in a similar manner, so it will not be described here.

According to a ninth aspect, an embodiment of the present invention provides an access device, the access device comprising:

a receiving module, configured to receive a radio frame received by the access point, wherein the radio frame indicates an access method for performing channel access, wherein the radio frame includes an association response frame, a beacon frame, or a received data frame. It is the response frame of the access point to - ; and

If the second frame carrying information about the uplink transmission resource is received from the access point within an agreed period, transmit uplink multi-user transmission data to the access point, or - the uplink multi-user transmission data is the uplink transmission resource sent on - ; or if the second frame is not received within the agreed period, the processing module, configured to access the channel in a contention access scheme based on carrier-sensing CSMA/CA

includes

According to a tenth aspect, an embodiment of the present invention provides an access device, the access device comprising:

a receiving module, configured to receive, from an access point, a first frame carrying information about an uplink transmission resource;

a transmitting module, configured to transmit a second frame carrying uplink transmission requirement information to the access point; and

Disabling the CSMA-CA based contention access scheme or disabling the backoff timer, and when a third frame carrying information about uplink transmission resources is received from the access point within an agreed period, uplink multi-user transmission transmit data to an access point, wherein the uplink multi-user transmission data is transmitted on an uplink transmission resource; or if the third frame is not received within the agreed period, the processing module is configured to enable the station to access the channel by enabling a CSMA-CA based contention access scheme.

includes

Some technical features in the above-described device embodiments, such as timers, uplink transmission resources, trigger frames, and radio frames, are similar to or correspond to some technical features in the above-described method embodiments, and thus will not be repeated herein. .

According to an embodiment of the present invention, a plurality of stations can simultaneously perform parallel random access on a plurality of channels as much as possible, and random access efficiency is improved. There are two ways in which the access point increases the chance of acquiring the channel. One way is for the station to delay contention or reduce the intensity of channel contention by the station, and the other way is for the station to hand over the control right to the access point after acquiring the channel by contention, and the access point has multiple To transmit a user-transmitted trigger frame.

The accompanying drawings are included and constitute a part of the specification and like reference numerals refer to like elements. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. 1 is a schematic flowchart of frame exchange of STA random access. 2 is a schematic diagram of a basic structure of an uplink random access packet. 3A is a schematic flowchart of frame exchange in Scenario 1 according to an embodiment of the present invention. 3B is a schematic flowchart of another frame exchange in Scenario 1 according to an embodiment of the present invention. 3C is a schematic flowchart of frame exchange in Scenario 2 according to an embodiment of the present invention. 3D is a schematic flowchart of frame exchange in scenario 3 according to an embodiment of the present invention. 3E is a schematic flowchart of frame exchange in Scenario 4 according to an embodiment of the present invention. 3F is a schematic flowchart of frame exchange in scenario 5 according to an embodiment of the present invention. 3G and 3H are schematic diagrams in which multiple transmission schemes operate jointly. 4 is a schematic flowchart of frame exchange of an access method according to Embodiment 4 of the present invention. 5 is a schematic diagram of several situations where a timer may need to be used. 5A is a schematic operation diagram of a first timer according to an embodiment of the present invention. 5B is a schematic operation diagram of a second timer according to an embodiment of the present invention. 5C is a schematic operation diagram of a third timer according to an embodiment of the present invention. 5D is a schematic operation diagram of a fourth timer according to an embodiment of the present invention. 6A is a first schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. 6B is a second schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. 6C is a third schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. 6D is a fourth schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. 7 is a schematic flowchart of frame exchange in a transmission mode conversion method according to an embodiment. 8 shows an access device according to an embodiment of the present invention.

Reference is made in detail to various embodiments of the present invention, examples being shown in the accompanying drawings. Although the description will be made with reference to these examples, it will be understood that these examples are not used to limit the invention to these examples. Instead, the present invention is intended to cover alternative techniques, modifications and equivalent techniques that may be included within the spirit and scope of the invention as defined in the appended claims. Further, in the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. It is to be understood, however, that in practical applications, these specific details of the present invention may not be included. In order to avoid unnecessarily obscuring various aspects of the present invention, well-known methods, processes, components, and circuits have not been described in detail in other instances.

In the IEEE 802.11ax system, a station (abbreviated as STA) mainly performs uplink access in the following several ways:

Scheme 1: Contention access scheme based on Carrier Sense Multiple Access with Collision Avoidance (abbreviated as CSMA/CA).

Scheme 2: Contention access scheme based on orthogonal frequency division multiple access (Orthogonal Frequency Division Multiple Access, abbreviated as OFDMA).

Scheme 3: OFDMA-based scheduling access scheme.

In the aforementioned scheme 1, the STA may voluntarily perform access using carrier sensing when the channel is in an idle state. In the aforementioned scheme 2, after receiving a trigger frame for random access (TFR for short) transmitted by the AP, the STA may randomly select a resource block to perform access. In the aforementioned method 3, after receiving a trigger frame transmitted by the AP, the STA may perform data transmission on a corresponding channel according to an indication of the trigger frame. In order for the AP to transmit a trigger frame to the STA, the STA must transmit a Buffer Size Report (abbreviated as BSR) to the AP, and the BSR is to be transmitted in the above-described manner 1, method 2 or other method. can

The OFDMA-based scheduling access scheme may be additionally performed using other access methods. For example, the STA may transmit a radio frame to the AP in manner 1 or manner 2, and the radio frame is used to trigger the STA to transmit uplink data (additionally triggering another STA to transmit uplink data). may) carry indication information used to indicate that the AP can transmit a trigger frame.

If each STA is able to perform data transmission in all three methods described above, when there are many STAs, many users can participate in CSMA/CA contention or OFDMA contention, so the possibility of collision between users is greatly increased. usability is reduced. An embodiment of the present invention provides a channel access method management mechanism, thereby reducing the contention level of the system and improving the channel utilization.

<b>Example 1: Multi-User Transport Framework</b>

When multiple users perform random access, the AP must provide a trigger frame in order for the signals of multiple users to reach the AP in an ordered manner. The basic process is as follows:

Step 1: The AP transmits a trigger frame, and the trigger frame is used to trigger the station to perform OFDMA-based random access.

Step 2: The station determines whether to transmit the random access packet according to the transmission condition. When the station decides to transmit the random access packet, the station transmits the random access packet within a specified time after receiving the trigger frame.

The transmission condition may be one or more of the following:

(1) The station generates a random backoff number within the contention window range for a packet to be transmitted, the station updates the random backoff number according to the quantity of resources for random access included in the trigger frame, and the backoff is When done, it decides to send a random access packet. Updating the random backoff number includes: new random backoff number=original random backoff numberquantity of resources for random access. Backoff is complete when any number of backoffs reaches zero.

(2) the station generates a random backoff number within a contention window range for a packet to be transmitted, and the station generates an access condition included in the trigger frame and resources for random access included in the trigger frame while corresponding to the access condition. The number of random backoffs is updated according to the quantity, and when the backoff is completed, it is decided to transmit a random access packet. The update includes: New random backoff number=original random backoff numberquantity of resources for random access. Backoff is complete when any number of backoffs reaches zero.

Transmission conditions include the requirements of the type of random access packet of the station (association request, Buffer Size Report, Idle/Available Channel Report, Channel Status Report, or Channel Quality/Signal-to-Interference and Noise Ratio Report), and / or may include a requirement for the service type of the random access packet.

The transmission condition may further include whether the station needs to determine whether the channel is in use or idle when performing access. A station only accesses a channel when the channel is idle, or a station updates the random backoff number only when the channel is idle.

In an embodiment of the present invention, a packet and a frame may be used interchangeably unless otherwise specified.

Step 3: The AP transmits an acknowledgment frame after receiving the random access packet of one or more stations. The acknowledgment frame includes acknowledgment indication information regarding successful reception of the random access packet by the AP.

Step 4: The station receives the acknowledgment frame, and according to the acknowledgment indication information, learns whether the random access transmitted by the station is successfully received by the AP.

During implementation, the AP may be a common station within the network.

1 is a schematic flowchart for frame exchange of STA random access. In this process, if the number of stations satisfying the transmission condition is greater than 1, the stations may transmit random access packets (eg, packets transmitted by STA 1 , STA 2 or STA 3 in FIG. 1 ) in parallel. have. 2 is a schematic diagram of a basic structure of an uplink random access packet. When an OFDMA-based access scheme is used, a random access packet of a specific format transmitted by a station is shown in FIG. 2 . High Efficient-Short Training Field (abbreviated as HE-STF), Legacy Long Training Field (abbreviated as L-LTF), Legacy Short Training Field (L-SIG) ), Repeat Legacy Short Training Field (abbreviated as RL-SIG), High Efficiency Signal Field A (HE-SIG-A), or High Efficiency Signal Field B (High Efficiency Signal Field A). Field B, HE-SIG-B) is used at the receiving end to detect a packet start event, synchronization or channel estimation and indicates the packet format. If the packet format is a high-efficiency (abbreviated as HE) packet format, the number of symbols in the high-efficiency long training field (HE-LTF) is further indicated. The station provides a channel estimation reference by transmitting a HE-STF signal and a HE-LTF signal on a subchannel. Optionally, the station may send a load signal after the HE-LTF signal.

The receiving end receives and analyzes the HE-STF front signal, the HE-STF front signal indicates the symbol quantity and the packet length of the HE-LTF, and the time of the data load or the symbol quantity of the data load can be obtained according to the packet length. . Since the receiving end receives the HE-STF signal, the receiving end can adjust and synchronize Automatic Gain Control (AGC). Then, the receiving end may receive the HE-LTF signal, and the receiving end may perform channel estimation based on the HE-LTF signal. If the packet length information indicates that there is a data load, the receiving end continues to receive the data load. The HE-LTF signal may be a row or column in a P matrix or a row or column in another orthogonal matrix, and may be selected from a set containing a low correlation sequence.

Based on the received HE-LTF signal, the receiving end may determine whether a HE-LTF sequence on a subchannel is used and/or may determine a corresponding received signal strength. Specifically, the receiving end performs channel estimation based on the received HE-LTF signal to obtain a channel coefficient h, and the channel coefficient may be plural (eg, when there is a single receiving antenna), or a vector (eg, For example, when there are multiple receiving antennas). The received signal power value may be obtained by performing a modular operation on h and calculating a squared value or performing other mathematical operations. The received signal power value depends on the channel gain and the transmit signal power of the transmitter. According to the received signal power value, it may be determined whether the HE-LTF sequence on the subchannel is used. If the power value is higher than the specified threshold, the receiving end may determine that the HE-LTF sequence on the subchannel is used. The physical layer of the receiving end may report the reception result of the HE-LTF to the MAC layer by adding a reception vector (rxvector) message to the reception start indication (RXstart indication). Specifically, the reception result may include a detection result for a subcarrier/subchannel/spatial flow/LTF sequence. Optionally, the detection result may be whether a HE-LTF sequence is used or a corresponding received signal strength.

In addition, the receiving end may set a threshold based on the noise power intensity or the noise and interference intensity existing before the uplink packet is received. Alternatively, some subchannels and/or HE-LTF sequences may be reserved when subchannels and/or HE-LTF sequences are allocated. The receiving end may set the threshold by measuring the noise power intensity or the noise and interference intensity on these reserved resources. The success rate, the false detection rate, and the drop rate, which determines whether a HE-LTF sequence is used, can be adjusted by adjusting the threshold.

<b>Example 2</b>

This embodiment provides an access method, the access method comprising:

transmitting a first frame carrying uplink transmission requirement information to the AP; and

If the second frame carrying uplink transmission indication information is received from the AP within an agreed period, and the uplink transmission indication information includes a resource indication and a transmission mode indication, transmit uplink multi-user transmission data to the AP; the multiple uplink users transmit data to be transmitted on the uplink transmission resource indicated by the resource indication according to the transmission mode (including modulation and coding scheme or transmission duration) indicated by the transmission mode indication; or if the second frame is not received within the agreed period, the station accessing the channel in a CSMA/CA based contention access scheme.

includes

The first frame may be transmitted using a CSMA/CA based contention access method or may be transmitted using an OFDMA access method. The uplink transmission requirement information includes packet arrival interval, packet size information, or traffic rate information. In addition, the uplink transmission requirement information may further include flow rate, bandwidth requirement information or BSR. After receiving the AP's acknowledgment frame or response frame corresponding to the first frame, the station increases the contention window parameter of the CSMA contention access, or stops updating the backoff number of the CSMA contention access, or the CSMA contention access It is possible to suppress the access method of CSMA contention access, including prohibiting . This implementation may lower the probability of a station's contention transmission attempt, thereby increasing the probability that the access point will succeed in transmission contention. The access point may instruct multiple users to perform simultaneous transmission after contention is successful, thereby improving the channel access efficiency.

The AP provides uplink transmission resources to the station by using the second frame. Specifically, the second frame may be a trigger frame. Also, the agreed period may be a duration with a specific length of time. The agreed period may be counted. The AP may add the target transmission time and/or timeout duration indication of the second frame to the acknowledgment frame or response frame for the first frame and may add to the beacon frame. The station obtains the agreed period according to the target transmission time and the timeout duration. Agreed Duration = Target Transmission Time + Timeout Duration. The timeout duration may be agreed upon in the protocol. The station may use the time when the AP's acknowledgment frame or response frame for the first frame is received + the timeout duration as the agreed period.

<b>Example 3</b>

The access method provided in Embodiment 2 may use a plurality of different scenarios. Accordingly, the present embodiment provides a process for performing access through interaction between an AP and an STA, corresponding to different scenarios (or different data transmission types or different service transmission types). Details are given below:

Scenario 1: Periodic constant rate data transmission

For example, the scenario is applicable to a voice service for which silence suppression is disabled. Voice service packets arrive periodically and the coding rate of the voice service determines the packet size.

As shown in FIG. 3A , after receiving the first frame transmitted by the STA and carrying the uplink transmission requirement information, the AP sends a preset first trigger frame carrying information about the uplink transmission resource. At the time of transmission to the STA, the STA performs uplink multi-user data transmission according to the instruction of the first trigger frame. The AP transmits a second trigger frame carrying information on uplink transmission resources to the STA at a preset second time point, and the STA performs uplink multi-user data transmission according to the instruction of the second trigger frame. The first trigger frame and the second trigger frame are the same as the second frame in Embodiment 2, and there may be a plurality of second frames.

In a scenario, the period can be either an absolute agreed-upon period or a non-absolute agreed-upon period. When this embodiment of the present invention is applied to a system in which carrier detection is to be performed, when the AP detects that the channel is in use, the AP delays the transmission and performs direct transmission when the channel is idle or after the backoff is completed perform transmission. Therefore, the transmission time of the trigger frame may be later than the agreed period and the agreed period is referred to as a non-absolute agreed-upon period and in other cases referred to as an absolute agreed-upon period.

The STA may start a periodic constant rate data transmission timer within an agreed period (eg, the first time point and the second time point in FIG. 3A ) of the trigger frame to deal with the timeout. When the STAN receives a trigger frame under a preset condition (including before the periodic constant rate data transmission timer times out), the STA may cancel the timer. If the trigger frame is not received under a preset condition, the STA may access the channel using another method.

For example, scenario 1 is further applicable to a voice service with a variable rate. Voice service packets arrive periodically, and the voice service uses variable rate coding to derive variable packet sizes. After the transmission of the first packet is completed, if there is subsequent data to be transmitted, the STA may request the AP to allocate more resources.

Specifically, after receiving the first trigger frame, the STA performs uplink multi-user data transmission according to the instruction in the first trigger frame (in this embodiment of the present invention, one performing uplink multi-user data transmission) Note that there may be more than one STA), the first trigger frame indicates a parameter such as a frequency band or transmission time of the STA's uplink multi-user data transmission. If the quantity of resources allocated by the AP is less than the quantity of resources requested by the STA, the STA may add a bandwidth indication to the uplink multi-user data transmission (or the remaining buffer size non-zero indication, that is, the buffer has data to be transmitted). If the bandwidth indication bit is 1, it indicates that the STA needs more uplink resources, and the AP may provide the uplink multi-user data transmission resource indication to the STA in a subsequent trigger frame. As shown in FIG. 3B , the AP may continuously transmit a trigger frame to the STA, and the trigger frame indicates resources for additional uplink multi-user data transmission. In this way, if the quantity of resources previously allocated by the AP is less than the quantity of resources required by the STA, the STA performs uplink multi-user data transmission on the uplink multi-user data transmission resource indicated by the trigger frame. can continue.

Scenario 2: Aperiodic constant rate data transmission

After receiving the first frame transmitted by the STA and carrying the uplink transmission requirement information, the AP sends an invalid data trigger frame to the STA, wherein the invalid data trigger frame includes an agreed period. The agreed period may be a time for the AP's beacon frame, a periodic time, or a combination of the two. The AP receives an acknowledgment from the STA for invalid data trigger frame 1. According to the acknowledgment, the AP transmits a trigger frame to provide uplink multi-user data transmission resources to the STA.

As shown in Figure 3c, the AP transmits invalid data trigger frame 1. After receiving invalid data trigger frame 1, the STA may perform uplink transmission and include an agreed sequence of uplink transmission frames (eg, LTF sequence or LTF sequence on a specific subchannel). The sequence may be specified by the AP by being included in the invalid data trigger frame 1, or may be specified by the AP when the STA and the AP are associated.

The AP receives the sequence on a specific subchannel. If the sequence is an agreed sequence with the STA, the AP sends a first trigger frame to the STA, and the first trigger frame is on an uplink multi-user data transmission resource allocated to the STA by the AP according to packet size information or traffic rate information. transport information about After receiving the first trigger frame, the STA performs uplink multi-user data transmission according to the uplink multi-user data transmission resource indicated by the first trigger frame.

When the beacon frame indicates the agreed duration of the invalid data trigger frame, or when the AP and the STA negotiate the agreed duration of the invalid data trigger frame, the STA determines the agreed duration of the invalid data trigger frame (e.g., FIG. The invalid data trigger frame timer may be started within the first time point of 3c). If an invalid data trigger frame is received under a preset condition (including before the periodic constant rate data transmission timer times out), the STA may cancel the timer.

The station may start an uplink data scheduling transmit timer. A first trigger frame (or a second frame carrying information about an uplink transmission resource) is received under a preset condition (including before the uplink data scheduling transmission timer times out), and the uplink data transmission of the STA If resource allocation information is included, the STA may cancel the timer. If the trigger frame is not received under a preset condition, the STA may access the channel using another method.

Scenario 3: Periodic constant rate data transmission

3D , after receiving the first frame transmitted by the STA and carrying the uplink transmission requirement information, the AP may contend for the channel and transmit trigger frame 1 after contention backoff is completed . After receiving the trigger frame 1, the STA may include buffer status report information or bandwidth request information in uplink multi-user data transmission. After the AP receives the request from the STA, the AP transmits a trigger frame 2, which indicates an uplink multi-user data transmission resource allocated to the station by the AP according to the user request. After receiving the trigger frame 2, the STA performs uplink multi-user data transmission according to the uplink multi-user data transmission resource indicated by the trigger frame.

Scenario 4: Aperiodic variable size data transmission

As shown in Figure 3e, after receiving the first frame transmitted by the STA and carrying the uplink transmission requirement information, the AP may contend for channel 1 and transmit trigger frame 1 after contention backoff is completed. And, trigger frame 1 includes a quantity of spatial flow or a quantity of LTF symbols or a sequence length for uplink transmission. After receiving the trigger frame 1, the STA may include an agreed sequence of uplink transmission frame 1 (eg, an LTF sequence or an LTF sequence on a specific subchannel).

The AP receives the sequence on the subchannel, and if the sequence is the sequence agreed with the STA, the AP transmits trigger frame 2. Trigger frame 2 may include a number jointly determined by the number of received sequences or subchannels, the number of sequences and the number of subchannels, and the AP transmits buffer status report information or bandwidth request information to the STA corresponding to the number. command to do Alternatively, trigger frame 2 carries the station identifier, and the AP instructs the STA with the station identifier to transmit buffer status report information or bandwidth request information.

After receiving the trigger frame 2, the STA transmits an uplink transmission frame 2 carrying a bandwidth request according to an indication of the trigger frame 2, and the uplink transmission frame 2 includes buffer status report information or bandwidth request information. After receiving the uplink transmission frame 2, the AP transmits a trigger frame 3 according to the uplink transmission frame 2 to allocate uplink resources to the STA. After receiving the trigger frame 3, the STA performs uplink multi-user data transmission according to the uplink multi-user data transmission resource indicated by the trigger frame 3.

Scenario 5: Aperiodic Low Latency Data Transmission

As shown in FIG. 3F , the STA may report the existence of aperiodic low delay data transmission to the AP. The AP transmits a trigger frame for random access, and the trigger frame indicates uplink multi-user data transmission resource allocation. At least one uplink resource (eg, OFDMA subchannel) is used for random access. After receiving the trigger frame, the station selects an uplink resource to perform uplink random access or not to perform uplink random access.

3G and 3H are schematic diagrams in which multiple transmission schemes operate jointly. As shown in FIGS. 3G and 3H , several transmission schemes applicable to different scenarios may operate jointly. When different types of data are to be transmitted, a corresponding transmission scheme may be selected or several transmission schemes may be selected at the same time to perform transmission, depending on a scenario to which data may be applied.

<b>Example 4</b>

This embodiment provides an access method, the access method comprising:

Receiving a first frame carrying information about an uplink transmission resource from the AP;

Transmitting a second frame carrying uplink transmission requirement information to the AP, disabling a CSMA-CA based contention access scheme, or stopping a CSMA-CA based contention backoff timer corresponding to an uplink transmission requirement information queue step; and

If the third frame carrying information about the uplink transmission resource is received from the AP within the agreed period, send uplink multi-user transmission data to the AP, or - the uplink multi-user transmission data is transmitted on the uplink transmission resource - ; or if the third frame is not received within the agreed period, the station enables the CSMA-CA based contention access scheme to access the channel or reuse the CSMA-CA contention access backoff timer corresponding to the uplink transmission requirement information queue. step

includes

The information about the uplink transmission resource in the third frame may further include identifiers of one or more stations using the uplink transmission resource. The backoff timer may further be a backoff counter.

The uplink transmission requirement information includes whether the STA has data to be transmitted, which may be indicated using 1 bit. A plurality of STAs may simultaneously transmit a second frame carrying uplink transmission requirement information (training portions of the second frame may be the same or overlapping, and load portions of the second frame may not overlap) ). In addition, enabling or disabling the CSMA-CA-based contention access scheme may be enabling or disabling the CSMA-CA-based contention access function by the STA. The third frame may be a trigger frame.

4 is a schematic flowchart of frame exchange of an access method according to Embodiment 4 of the present invention. As shown in FIG. 4 , the AP carries a first frame (eg, a data frame or a trigger frame) that carries information about an uplink transmission resource (which may be regarded as indication information such as indication information in FIG. 4 ). is used to transport indication information) to the STA. The indication information indicates an uplink transmission resource that can be allocated to the STA to perform uplink multi-user transmission (that is, the access point uses the first frame to notify the station that there is an available uplink transmission resource, and , the access point uses the first frame to instruct any user to respond to the first frame without requiring a backoff). An STA that needs to perform uplink multi-user data transmission may transmit uplink transmission requirement information according to the indication information. The AP may additionally instruct a parameter for the STA to perform uplink multi-user data transmission according to the indication information (eg, uplink transmission resource used by the STA, usage method or subchannel, spatial flow). may indicate the allocation of , or a modulation and coding scheme). The STA generates, according to the parameter, a second frame carrying uplink transmission requirement information (eg, a frame carrying 26-tone RU information). Since all STAs use the same parameters, the generated second frame is the same. Therefore, even if a plurality of users transmit a frame using the same resource, signals of the plurality of users do not interfere with each other, and the AP can receive one or more second frames (which may be a plurality of overlapping second frames). . After receiving the second frame, the AP may transmit a third frame (eg, a trigger frame for random access). If the AP does not occupy the TXOP or the third frame exchange cannot be completed in the remaining TXOP time, the AP may contend for the channel and transmit the third frame after contention backoff is complete. If the AP occupies the TXOP, the AP may transmit a trigger frame. After receiving the trigger frame, the STA performs uplink multi-user data transmission according to the trigger frame.

Table 1 lists three technical solutions for triggering data transmission. In technical solution 1, a specific user is designated to perform transmission on a specific resource (the station does not need to perform contention backoff). In technical solution 2, a random user is designated to perform random transmission within a specific resource range. In the technical solution provided in this embodiment, any user is designated to perform transmission on a specific resource. After receiving the second frame, the AP is allowed to trigger multi-user data transmission. For example, the AP may trigger multi-user data transmission using technical solutions 1 or 2 in Table 1.

<tables num="1"><table><tgroup cols="3"><colspec colnum="1" align="justify" colname="col1" colwidth="3493" /><colspec colnum="2" align="justify" colname="col2" colwidth="3404" /><colspec colnum="3" align="justify" colname="col3" colwidth="3454" /><tbody><row><entry align="justify" colname="col1">Technical solution 1: OFDMA scheduling scheme</entry><entry align="justify" colname="col2">specific user</entry><entry align="justify" colname="col3">specific resource</entry></row><row><entry align="justify" colname="col1">Technical solution 2: OFDMA contention scheme</entry><entry align="justify" colname="col2">any user</entry><entry align="justify" colname="col3">One or more resources (stations need to perform contention backoff)</entry></row><row><entry align="justify" colname="col1">Technical solution in this embodiment</entry><entry align="justify" colname="col2">any user</entry><entry align="justify" colname="col3">Specific resource (the station does not need to perform contention backoff)</entry></row></tbody></tgroup></table></tables>

<b>Comparison between the solution provided in the example and other solutions</b>

<b>Example 5</b>

When initially accessing the AP, the STA may determine the channel access method according to the command of the AP, negotiate the channel access method with the AP, and the channel access method may be predetermined in the protocol.

Specifically, when initially accessing a channel, the STA learns a channel access method for accessing the AP by receiving a beacon frame. If the AP does not provide an indication, the default channel access scheme is used (eg, the default access scheme is a CSMA-CA based contention access scheme). The STA transmits an association request frame to the AP. The association request frame carries information about the channel access method support capability/policy of the STA or information about the version of the station, and this information indicates the default support capability of the STA. Alternatively, the AP obtains the default supported capability of the STA according to the format of the association request frame (eg, frame version/modulation and coding scheme). After receiving the association request frame, the AP transmits an association response frame to the STA. The association response frame carries the channel access policy (eg, carries information indicating the channel access method used by the STA to access the channel).

For example, when the STA performs initial access, the AP may designate an access method for the STA according to information about the currently connected STA (eg, the access method or the number of connected STAs). If there are many connected STAs, an OFDMA-based scheduling access scheme may be used.

<b>Example 6</b>

This embodiment provides timer design and timeout processing in the access process, for example, timing processing for an agreed period in each embodiment of the present invention. The detailed description is as follows:

5 is a schematic diagram of several situations where a timer may need to be used. 5, in the case of an overlapping basic service set (Overlapping Basic Service Set, abbreviated as OBSS), the AP backs off when detecting that the channel is in use, and the trigger frame transmission within the agreed period is delayed. After the channel becomes idle, the AP contends for the channel, acquires the channel by contention, and then transmits a trigger frame.

When the STA is within the coverage area of the OBSS, the AP completes the backoff if it does not detect that the channel is in use, and the AP transmits a trigger frame. Since the STA is affected by transmission interference or noise or other environmental factors in the OBSS, if the STA does not receive the trigger frame of the AP, the STA continues to wait. However, since the AP has transmitted the trigger frame and the STA has not received the trigger frame of the AP, the STA needs to actively perform EDCA contention.

If both the AP and the STA are within the coverage area of the OBSS, the AP stops counting the backoff count when it detects that the channel is in use and does not restart counting the backoff count until the channel becomes idle. After the backoff is completed, the AP transmits a trigger frame. Since the STA can monitor the transmission of the OBSS, the STA can infer that the AP will delay the trigger frame transmission due to the OBSS. The STA may wait for a long time, that is, the STA may consider the transmission delay caused by the ODSS while waiting.

Specifically, the STA may set a timer (or backoff counter) at the agreed trigger frame arrival time, and a timer (or backoff counter) after receiving an uplink packet or after the STA's queue changes from empty to non-empty. counter) can also be set.

5A is a schematic working diagram of a first timer according to an embodiment of the present invention. As shown in FIG. 5A , when the STA has uplink data to be transmitted or when the STA's queue changes from empty to non-empty, the STA or queue starts counting down. The duration of the countdown may be specified by the AP and may be agreed upon in the protocol.

5B is a schematic working diagram of a second timer according to an embodiment of the present invention. As shown in FIG. 5B , after the STA receives an uplink packet or after the STA's queue changes from empty to non-empty, the STA or queue sets the number of backoffs. The backoff number may be specified by the AP or may be agreed upon in the protocol. When the channel is idle, the number of backoffs gradually decreases. Specifically, the number of backoffs may gradually decrease by 1 after each unit time elapses. If the channel is in use, the gradual decrease in the number of backoffs stops.

5C is a schematic working diagram of a third timer according to an embodiment of the present invention. As shown in FIG. 5C , after the STA receives an uplink packet or after the STA's queue changes from empty to non-empty, the STA or queue sets the number of backoffs. The backoff number may be specified by the AP or may be agreed upon in the protocol. When the channel is idle, the number of backoffs gradually decreases. Specifically, the number of backoffs may gradually decrease by 1 after each unit time elapses. If the channel is in use, the gradual decrease in the number of backoffs stops. Further, upon receiving the trigger frame for uplink random access transmitted by the AP, the STA updates the number of backoffs, for example, increases the number of backoffs. Receiving the trigger frame indicates that the AP has contention triggering multiple users to perform uplink transmission. The AP acquires a channel by contention and transmits a trigger frame for uplink random access. In order to increase the probability that the AP acquires the channel by contention, the STA actively lowers the contention intensity for the channel by the STA. Specifically, the STA may add a constant based on the current backoff number and this constant is preset in the protocol or specified in the message frame (eg, association response frame or beacon frame) by the AP. Alternatively, the current number of backoffs may be multiplied by a constant. The constant is preset in the protocol or specified in the message frame by the AP.

5D is a schematic working diagram of a fourth timer according to an embodiment of the present invention. As shown in Figure 5d, when the STA performs uplink transmission, for example, sending a buffer size report or bandwidth request, and receiving the AP's acknowledgment frame for successful transmission , the STA sets the number of backoffs. Can be updated. Since the STA has transmitted the amount of data to be transmitted or requested bandwidth information to the AP, the AP allocates resources to the STA. Therefore, the STA can increase the AP scheduling opportunity by reducing the contention intensity for the channel by the STA by updating the backoff number.

<b>Example 7</b>

After the STGA acquires the channel, the STA may hand over the control right to the AP, and the AP instructs one or more STAs to perform uplink multi-user data transmission.

6A is a first schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. As shown in FIG. 6A , the STA accesses the channel in an EDCA manner and transmits a single-user physical layer protocol data unit (Physical layer Protocol Data Unit, abbreviated as SU-PPDU). The AP receives the SU-PPDU transmitted by the STA, and the AP responds with an acknowledgment frame or a block acknowledgment frame. The AP may indicate in the frame that the AP will transmit a multi-user transmit trigger frame using a control channel. For example, the AP may use 1 bit to indicate that it will transmit a multi-user transmit trigger frame using a control channel, in a frame. After the STA receives the frame, if the AP indicates in the frame that it will transmit a multi-user transmit trigger frame using the control channel, the STA may transmit an acknowledgment frame (the acknowledgment frame is the uplink by the AP using the control channel) Used to confirm transmitting a frame for triggering multi-user data transmission, otherwise the STA continues to transmit the uplink SU-PPDU.

After receiving the STA's acknowledgment frame, the AP transmits a multi-user data trigger frame. The AP may include information about an uplink transmission resource of the STA or an uplink transmission resource of an STA different from the STA in the trigger frame. After the STA's acknowledgment frame is received, the trigger frame may be transmitted after the SIFS time.

Optionally, after receiving the STA's acknowledgment frame, the AP may transmit a multi-user transmit trigger frame after an interval of period 1 (an agreed period longer than SIFS). During this time, the AP detects whether the channel is in use or idle. If the channel is idle, the AP transmits a multi-user transmit trigger frame. If the channel is in use, the AP transmits a packet whose transmission time is shorter than the threshold, this short packet may be an acknowledgment frame or other short frame, and the STA may continue to use the channel after receiving the short packet. Alternatively, if the channel is in use, the AP may not transmit data packets. When the STA does not detect that the channel is in use or that there is data to be transmitted for a period of time (eg, a time longer than period 1), the STA may continue to transmit the data packet.

6B is a second schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. As shown in FIG. 6B , the AP transmits an acknowledgment frame or block acknowledgment frame after receiving the uplink SU PPDU, and transmits a multi-user transmission trigger frame after the SIFS time. Compared with the method shown in FIG. 6A , after the AP transmits the acknowledgment frame or block acknowledgment frame, the AP directly directs the STA to perform uplink multi-user data transmission without needing to wait for receiving the acknowledgment frame acknowledged by the STA. can trigger.

Optionally, Figure 6c is a third schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. As shown in FIG. 6C , the AP transmits an acknowledgment frame or block acknowledgment frame after receiving the uplink SU-PPDU, and the acknowledgment frame carries uplink transmission trigger information. In this case, the AP does not need to use 1 bit to indicate in the frame that the AP transmits a multi-user transmit trigger frame using a control channel. After one or more STAs receive the information, the STA transmits uplink multi-user transmission data according to the uplink transmission trigger information.

6D is a fourth schematic diagram of transmitting a multi-user transmission trigger frame according to an embodiment of the present invention. As shown in FIG. 6D , the STA transmits an RTS packet and the AP responds with a CTS packet. The AP may use the CTS packet to indicate whether a multi-user transmission trigger frame needs to be transmitted using the control channel.

When the AP needs to transmit a multi-user transmission trigger frame by using the control channel, in the STA supporting this interaction process (eg, the STA supporting the protocol version, or the STA supports this interaction process) A STA that notifies the AP that the AP is doing, or a STA that supports handover of the channel control authority), the AP may fill the MAC address of the AP into a receive address (RA) of the CTS. Otherwise, the AP may fill the RA of the CTS with the MAC address of the RTS transmitter. After the STA receives the CTS, if the RA address carried in the CTS is the address of the AP, the STA transmits a short packet (eg, an acknowledgment frame), and the AP sends a multi-user transmission trigger frame after receiving the short packet send The AP may include uplink transmission resource indication information of the STA or of an STA different from the STA in the multi-user transmission trigger frame. After receiving the multi-user transmission trigger frame, the STA performs data transmission according to the uplink transmission resource indication information.

<b>Example 8</b>

This embodiment of the present invention proposes an access method of the STA (eg, the three uplink access methods described above), and this access method may be designated by the AP. After the AP designates an access method to the STA, the STA may perform access and data transmission only with the access method designated by the AP. The AP may designate an access method by transmitting a radio frame to the STA. The radio frame may carry indication information used to indicate the access method of the STA. The radio frame may be a beacon frame or an association response frame.

Specifically, this embodiment proposes an access method, the access method comprising:

Receiving a radio frame transmitted by the AP, wherein the radio frame indicates an access method for performing channel access, and the radio frame is an association response frame, a beacon frame, or a response frame of the AP to a received data frame. Lim); and

When a second frame (eg, a trigger frame) carrying information about an uplink transmission resource is received from the AP within an agreed period, transmitting uplink multi-user data to the AP, wherein the uplink multi-user data is transmitted on the uplink transmission resource, or if the second frame is not received within the agreed period, the station accessing the channel in a CSMA-CA based contention access scheme;

includes

If the radio frame is a beacon frame, the specific process of this embodiment is as follows:

Step 1: The AP generates a beacon frame, and the beacon frame carries indication information used to indicate an access method of the STA.

Step 2: The AP transmits a beacon frame.

The indication information in step 1 may be public information shared by all STAs, or may be private information dedicated to one or more STAs and individually instructing each STA a transmission method. In the latter, the beacon frame may further include identifiers (eg, association identifier AIDs) of one or more STAs.

The indication information transmitted to each STA may be a field. A value of the field may indicate one or more transmission schemes that may be used by the STA. The indication information may be a bitmap. Each bit may indicate whether a transmission scheme can be used.

If the radio frame is an association response frame, the specific process of this embodiment is as follows:

Step 1: The STA transmits an association request frame to the AP.

Step 2: The AP transmits an association response frame to the STA, and the association response frame includes indication information used to indicate an access method of the STA.

In addition, the association request frame and association response frame in steps 1 and 2 may be a reassociation request frame and a reassociation response frame. The process is the same, and this will not be described again here.

<b>Example 9</b>

According to the access method used by the STA, there are three data transmission states of the STA:

Contention state: The STA may perform data transmission only in a contention-based method, for example, only in method 1 and/or method 2 among the above-described three access methods.

Scheduling state: The STA may perform data transmission only in a scheduling-based scheme, for example, only in scheme 3.

Mixed state: The STA may perform data transmission in a contention-based scheme and a scheduling-based scheme, for example, in any one of scheme 1, scheme 2, or scheme 3.

The AP assigns an access method to the STA, which actively assigns the STA a data transmission state. However, the data transmission state of the STA needs to change with time. For example, if there are few STAs in the system, the mixed state of the STAs is more conducive to transmitting the STA's data. When there are many STAs, the contention state or scheduling state of the STAs helps to improve overall system performance. Therefore, this embodiment proposes a method for switching the data transmission state of the STA.

When the STA is in the data transmission state and successfully transmits the data frame to the AP, the AP transmits a response frame to the STA, and the response frame carries indication information used to indicate the data transmission method of the STA (or the STA). can enter the data transfer state). The specific process is as follows:

Step 1: The STA transmits a radio frame to the AP. The radio frame may be a data frame.

Step 2: The AP transmits a response frame to the STA, and the response frame carries indication information used to indicate a data transmission method of the STA.

If the STA is in contention state and successfully transmits a data frame to the AP, and the AP finds that there are many STAs in the system at this time, the AP is in a contention state, affecting the overall system performance, so the AP responds to the STA in the response frame. By transmitting the indication information, the STA enters a scheduling state, thereby reducing the degree of contention in the system and improving overall channel resource utilization.

Alternatively, the AP may use the indication information to allow the STA to enter the mixed state from the contention state. The STA has to monitor the channel to receive the trigger frame or chooses to transmit a buffer state report (BSR) instead of directly transmitting the data frame.

Likewise, the AP also uses the indication information to allow the STA to enter the contention state from the mixed state. In this case, the STA can only transmit data in way 1 and/or way 2, which affects economic access policy selection by the AP.

It should be noted that step 1 in the above process may be omitted, that is, the AP directly transmits a radio frame to the STA, and this radio frame carries indication information used to indicate the data transmission method of the STA. .

In addition, the STA may determine the transmission mode according to a specific rule when the indication information is not received. For example, the STA uses an OFDMA-based scheduling access scheme by default. Optionally, if the STA uses an OFDMA-based scheduling access scheme, a timer may be set. After the timer times out, the STA may use a CSMA/CA-based contention access scheme or an OFDMA-based contention access scheme.

<b>Example 10</b>

In the OFDMA-based contention access scheme, the AP transmits a trigger frame for random access (TFR for short) and designates one or more subchannels in the TFR for random access. After receiving the TFR, if a condition is satisfied (or a condition corresponding to the TFR is satisfied), the STA may randomly select a subchannel for random access and perform transmission. Since the STA randomly selects the subchannel, the probability of collision is relatively high. According to our analysis, the highest channel utilization of this method is about 37%. If a large number of STAs jointly participate in the competition, channel utilization may be lowered. Therefore, this embodiment provides the following three data transmission methods.

Method 1: When the condition is met after the STA receives the TFR:

The STA transmits an unsegmented data frame (eg, an unsegmented MAC layer protocol data unit (MAC layer Protocol Data Unit, abbreviated as MSDU)) within the time specified by the TFR; or

If the STA transmits an aggregated MPDU including a plurality of PDDUs within a time specified by the TFR, the plurality of MPDUs includes the maximum of one fragmented data frame, and the last MUDU includes an unsegmented data frame.

Method 2: After receiving the TFR, the STA does not allow transmitting the data frame unless the data frame carries a buffer status report BSR.

Scheme 3: After receiving the TFR, the STA is not allowed to transmit the data frame.

<b>Example 11</b>

In the OFDMA-based scheduling access scheme, after receiving the trigger frame transmitted by the AP, the STA may perform data transmission on a corresponding channel according to an indication of the trigger frame. Before the AP transmits a trigger frame to the STA, the STA must transmit a buffer status report BSR to the AP. The BSR may be transmitted in a CSMA/CA-based contention access scheme (Scheme 1) or an OFDMA-based contention access scheme (Scheme 2). In view of the problem of whether a STA can transmit a BSR (or other control frame/management frame) with two contention access schemes, this embodiment proposes the following several feasible solutions.

Solution 1: The STA may perform the step of simultaneously transmitting in method 1 and method 2. That is, the STA may simultaneously enable two backoff processes, one used for the CSMA/CA-based contention access scheme and the other for the OFDMA-based contention access scheme.

Solution 2: The STA performs a step of transmitting in one of scheme 1 and scheme 2, and the STA determines to select scheme 1 or scheme 2.

Solution 3: The AP designates a STA to perform the step of transmitting in scheme 1 and/or scheme 2. That is, the AP transmits a radio frame to the STA, and the radio frame is used to designate the STA to perform the transmission in method 1 or method 2 or both methods. The radio frame may be a beacon frame, an association response frame, or a re-association response frame. For example, the AP includes indication information indicating a transmission method of the STA in a beacon frame, the STA reads the beacon frame to obtain a transmission method, and transmits an association request frame to the AP by this transmission method.

<b>Example 12</b>

This embodiment proposes a transmission mode switching method. After acquiring a TXOP by acquiring a channel by contention in a CSMA/CA-based manner, the STA may transmit a radio frame to the AP and handover the TXOP to the AP. The AP may start uplink multi-user transmission using TXOP and needs to schedule the STA in the uplink multi-user transmission. The specific process is as follows:

Step 1: The STA accesses the channel in the CSMA/CA-based contention access method and transmits a radio frame after contention is successful, this radio frame carries indication information, and the indication information is transmitted by the AP after receiving the radio frame Used to indicate that it can instruct the STA to perform uplink multi-user data transmission, and the AP needs to schedule the STA in the uplink multi-user transmission.

Step 2: After receiving the radio frame, the AP transmits a trigger frame after a preset time, and this trigger frame carries scheduling information for triggering the STA to transmit a data frame (also, other STAs may be triggered have).

Step 3: The STA transmits a radio frame according to the trigger information of the AP.

Step 4: The AP transmits a multi-user block ACK (abbreviated as MBA) frame.

In addition, the STA may indicate whether the AP can continue to transmit another frame after transmitting the MBA in step 4 by adding indication information to the radio frame in step 3 . The other frame may be a trigger frame or a downlink data frame. If the indication information indicates that the AP can continue to transmit another frame, after transmitting the MBA in step 4, the AP transmits a radio frame after a preset time. The preset time may be SIFS, and the radio frame may be a trigger frame or a downlink data frame. If the indication information indicates that the AP cannot continue to transmit another frame, after transmitting the MBA in step 4, the AP cannot transmit the radio frame. The STA may transmit a radio frame after a preset time, and the preset time may be SIFS.

<b>Example 13</b>

This embodiment provides a transmission mode switching method. After acquiring a TXOP by acquiring a channel by contention in a CSMA/CA-based contention access scheme, the STA may transmit a radio frame to the AP, and the AP is allowed to schedule another STA to share the TXOP with the STA. A specific sharing scheme may be an OFDMA scheme or a multi-use MIMO scheme. As the owner of the TXOP, the STA has the authority to control whether the current TXOP is for multi-user transmission or single-user transmission, and the right to control the transmission time of single-user transmission or multi-user transmission.

7 , this embodiment provides a transmission mode switching method, including the following steps:

Step 1: STA 1 transmits a first frame to the AP in the TXOP indicated by STA 1, the first frame carries first indication information, the first indication information triggers the AP to transmit uplink multi-user data Used to indicate that you can.

Step 2: After receiving the first frame of STA 1, the AP transmits a trigger frame after a preset time.

The trigger frame must carry scheduling information for triggering the STA to transmit the data frame (ie, the STA is guaranteed to be triggered while another STA can be further triggered). Scheduling information is: If an uplink multi-user MIMO (UL MU-MIMO) transmission scheme is used, a space-time stream is allocated to each uplink user, and an uplink orthogonal frequency division multiple access (UL OFDMA) transmission scheme is used. , allocates a frequency domain subband to each uplink user, and if the UL OFDMA transmission scheme and the UL MU-MIMO transmission scheme are used, a frequency domain subband is allocated to each uplink user and in this frequency domain subband Each user is assigned a space-time stream.

The AP responds to the first frame (transmits an ACK frame or block ACK BA) frame at the same time when transmitting the trigger frame before transmitting the trigger frame. Specifically, after the AP receives the first frame of STA 1, the response frame acknowledged by the AP may receive the second indication information, and the response frame acknowledged by the AP may carry the second indication information, The second indication information is used to indicate whether the AP complies with the indication of STA 1. That is, the AP may additionally use the second indication information to reject using the UL MU transmission, and may respond to the first frame in a conventional manner.

Step 3: STA 1 transmits the second frame according to the information carried in the trigger frame transmitted by the AP. The second frame is transmitted in UL MU format. According to the indication of the trigger frame transmitted by the AP, the UL MU format may be the user's frame format in UL OFDMA (ie, the second frame is located in the frequency domain subchannel allocated by the AP), or the UL MU - May be the user's format in MIMO (ie, the second frame is located in the spatial flow/space-time stream allocated by the AP).

According to the indication of the trigger frame, other STAs (eg, STA 2 ) and STA 1 other than STA 1 transmit APDP data using the UL MU scheme.

Step 4: The AP transmits a response frame, which simultaneously responds to data frames (or UL MU data frames) transmitted by multiple users. The response frame may be a multi-user block acknowledgment MBA (multi-user block ACK) frame or an acknowledgment (ACK/BA) frame that is transported in a downlink multi-user (DL MU) scheme.

In addition, the STA may also indicate whether the AP can continue to trigger UL MU transmission in a subsequent transmission by adding the first indication information to the second frame in step 3 . Also, when transmitting the response frame, the AP may choose to use the DL MU transmission scheme to transmit data of one or more users to each user. Therefore, if STA 1 can continue UL MU transmission in step 3, then in step 4, the AP may respond to the multi-user data frame in step 3 by using an independent trigger frame, triggering with DL MU using DL MU It may respond with information or downlink multi-user data frames by transporting frames.

In this embodiment, if the first indication information in the frame transmitted by STA 1 indicates that the AP cannot trigger UL MU transmission (not authorized as indicated by frames 1-3 shown in FIG. 7 ) multi-user), the AP cannot trigger UL MU transmission in a subsequent transmitted frame.

In this embodiment, the transmission of STA 1, which is the owner of the TXOP, determines the transmission length of the TXOP. Therefore, if the transmission of STA 1 is terminated and the unauthorized AP continues to use the TXOP, STA 1 may transmit a Contention Free-End (abbreviated as CF-End) frame to terminate the TXOP. . If the AP triggers one or more STAs to transmit data using the UL MU, the data length of STA 1 should be used as a reference for the transmission time, that is, the transmission of other STAs cannot exceed the transmission length of STA 1.

In this embodiment, the preset time may be SIFS or other fixed time such as SSIFS or PIFS. The first indication information in this embodiment is located in the HE control field, the second indication information is also located in the HE control field, and the information bits of the first indication information can even be reused.

Also, in this process, if STA 2 is in UL MU format and in a frame transmitted by STA 2 indicates that data transmission is not complete (eg, more data bits are set to 1), the AP may indicate, in a subsequent trigger frame, that the transmission of some data has not been completed (a specific form may be to reuse more data bits or to use other dedicated information bits). As the owner of the TXOP, STA 1 may consider information for determining whether to continue to allow UL MU transmission. When the AP triggers UL MU transmission, STA 1 indicates information about the minimum resource allocated to STA 1 in the authorized UL MU while instructing UL MU transmission authorization, so the AP is the owner of the TXOP, STA 1 You can allocate very few resources to For example, if the AP subsequently triggers UL OFDMA transmission, STA 1 may indicate that the minimum bandwidth that the AP allocates to STA 1 cannot be less than 20 MHz.

<b>Example 14</b>

This embodiment of the present invention can be applied to the scenario of multi-user uplink contention.

When a station has a data packet to be transmitted or when the station sends a buffer size report and receives an acknowledgment frame acknowledged by the AP, there are three cases: 1. If the trigger frame is received within the agreed period, OFDMA access scheme (This may be an OFDMA contention access scheme or an OFDMA scheduling access scheme) is used to transmit data, or if a trigger frame is not received within an agreed period, a CSMA/CA based contention access scheme is used to transmit data. 2. A CSMA/CA-based contention access scheme with a relatively large CW is used within the agreed period to transmit data, and a CSMA/CA-based contention access scheme with a relatively small CW is used after the agreed period to transmit data. 3. The size of the CW decreases at the end of the agreed period.

From the target transmission time of the trigger frame indicated by the beacon frame or the target transmission time of the trigger frame negotiated by the station and the AP, there are three cases: 1. If the trigger frame is received within the agreed period, OFDMA access method ( This may be an OFDMA contention access scheme or an OFDMA scheduling access scheme) is used to transmit data, or if a trigger frame is not received within an agreed period, a CSMA/CA based contention access scheme is used to transmit data. 2. A CSMA/CA-based contention access scheme with a relatively large CW is used within the agreed period to transmit data, and a CSMA/CA-based contention access scheme with a relatively small CW is used after the agreed period to transmit data. 3. The size of the CW decreases at the end of the agreed period.

For the agreed period described above, the station may set a timer to count the agreed period. Channel access method 1 (eg, OFDMA access method with relatively large CW or CSMA/CA based contention access method (when a trigger frame is received)) is used before the timer expires. Channel access method 2 (eg, OFDMA access method with relatively small CW or CSMA/CA-based contention access method (when a trigger frame is received)) is used after the timer expires. After the trigger frame is received from the AP, the timer is canceled. Before the timer times out, one way is for the station to delay contention or reduce the contention strength for the station's channel). In addition, if the channel is acquired by contention, the station may hand over the control right to the AP, and the AP transmits a multi-user transmission trigger frame. The trigger frame may carry information about an uplink transmission resource.

When event 1 occurs, the station uses an access scheme that suppresses CSMA contention access. When event 2 occurs, the station uses an access scheme that promotes CSMA contention access. The access method for suppressing the CSMA contention access is: increase the contention window parameter of the CSMA contention access, stop updating the backoff number of the CSMA contention access, or disable the CSMA contention access. The access scheme to promote CSMA contention access is: reduce contention window parameter of CSMA contention access, reuse/start backoff number update of CSMA contention access, or enable CSMA contention access.

Event 1 may be that the station has a data packet to be transmitted or the station sends a buffer size report and receives an acknowledgment frame acknowledged by the AP. Event 2 may be that the timer expires and the trigger frame sent by the AP is not received, and so on. The AP provides an event indication, which is used to indicate (explicitly or implicitly) which station to use the channel access scheme. For example, the event indication may be information about an uplink transmission resource carried in a trigger frame transmitted by the AP.

<b>Example 15</b>

8 shows an access device according to an embodiment of the present invention. As shown in Fig. 8, this embodiment provides an access device, the access device comprising:

a transmitting module 801, configured to transmit a first frame carrying uplink transmission requirement information to the access point; and

When the second frame carrying information about the uplink transmission resource is received from the access point within an agreed period, it transmits multi-user transmission data to the access point, or wherein the multi-user transmission data is transmitted on the uplink transmission resource. ; or if the second frame is not received within the agreed period, the processing module 802, configured for the station to access the channel in a contention access scheme based on carrier sensing CSMA/CA.

includes

Optionally, the access device further comprises a timing module 803, configured to count the agreed period using a timer, the initial value of the timer being specified by the access point or agreed upon in a protocol.

Optionally, the access device further comprises a receiving module 804, configured to receive a radio frame received by the access point, the radio frame indicating a transmission time of a second frame, the radio frame being an association response frame , a beacon frame, or an access point's response frame to a received data frame.

Some technical features in the above-described device embodiments, such as access methods, timers or other additional descriptions (eg trigger frames), are similar to or correspond to some technical features in the above-described method embodiments, so it is repeated here do not explain

Also, corresponding to the above-described method, an embodiment of the present invention further provides an access device. The apparatus includes a memory and a processor, wherein the memory is configured to store instructions required by the processor for execution, and the processor is configured to execute the method in the above-described embodiment. Also, the apparatus may further include a transmitter and a receiver configured to transmit and receive data, respectively.

According to the embodiment of the present invention, as described herein, the present invention has been described in specific embodiments, but it should be understood that the present invention is not limited to these embodiments but is described in accordance with the claims.