Delivery of information over a communication channel
Abstract
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46 claims: 29 independent, 17 dependent
- 1無線通信システム上で情報を伝送する方法であって、 情報単位の間隔の間に発生する利用可能な通信チャネルにおける伝送の数を決定することと;前記利用可能なチャネル に使用 可能な物理層データパケット サイズ を決定することと;前記情報単位をスライスに区分することと、なおここでは、スライスの数は、前記情報単位の前記間隔の間の前記伝送の数以下であり、そして、前記スライスのサイズは、前記利用可能な通信チャネルの前記物理層データパケットサイズの1つを越えないように選択される;を含む、方法。
- 2情報を区分することは、可変サイズの区分を生成できるレート制御モジュールを備えたソースエンコーダ によって行われる 、請求項 1 記載の方法。
- 3複数の情報単位を更に備え、前記情報単位は固定レートで発生する、請求項 1 記載の方法。
- 4前記複数の情報単位は情報のフレームである、請求項 3 記載の方法。
- 5前記情報単位は可変ビットレートデータストリームを備える、請求項 1 記載の方法。
- 6前記情報単位はマルチメディアデータを備える、請求項 1 記載の方法。
- 7前記情報単位はビデオデータを備える、請求項 1 記載の方法。
- 8前記情報単位はオーディオデータを備える、請求項 1 記載の方法。
- 9前記通信チャネルはCDMAチャネルである、請求項 1 記載の方法。
- 10前記通信チャネルはGSMチャネルである、請求項 1 記載の方法。
- 11前記通信チャネルはEDGEチャネルである、請求項 1 記載の方法。
- 12前記通信チャネルはGPRSチャネルである、請求項 1 記載の方法。
- 13前記通信チャネルはタイムスロットチャネルである、請求項 1 記載の方法。
- 14前記情報単位をスライスに区分するようにエンコーダを制約することを更に含み、個々のスライスの前記サイズは物理層データパケットの前記サイズ以下である、請求項 1 記載の方法。
- 15前記情報単位をスライスに区分するようにエンコーダを制約することを更に含み、前記スライスの数は、前記情報単位の前記間隔の間の前記伝送の数以下である、請求項 1 記載の方法。
- 16前記通信システムはCDMAシステムである、請求項1記載の方法。
- 17前記通信システムはタイムスロットの中でデータを伝送する、請求項1記載の方法。
- 18前記通信システムはGSMシステムである、請求項1記載の方法。
- 19前記通信システムはEDGEシステムである、請求項1記載の方法。
- 20前記通信システムはGPRSシステムである、請求項1記載の方法。
- 21情 報単位間隔の1間隔の間に発生する無線通信システムにおける伝送の数を決定することと;複数の情報単位をスライスに区分することと、なおここでは、スライスの数は、前記複数の情報単位間隔の間の伝送の数以下である;を さらに 含む 、請求項1記載の 方法。
- 22情 報単位の間隔の間に発生する利用可能な通信チャネルにおける伝送の数を決定する ための手段 と;前記利用可能なチャネル に使用 可能な物理層データパケット サイズ を決定する ための手段 と;前記情報単位をスライスに区分する ための手段 と、なおここでは、スライスの数は、前記情報単位の前記間隔の間の前記伝送の数以下であり、そして、前記スライスのサイズは、前記利用可能な通信チャネルの前記物理層データパケットサイズの1つを越えないように選択される;を 備える無線通信デバイス 。
- 23可能な物理層データパケットサイズを決定するための前記手段は、コントローラを備え、 前記情報単位をスライスに区分するための前記手段は、エンコーダを備える 、 請求項22記載の 無線通信デバイス。
- 24前記物理層パケットを伝送するように構成された送信機を更に備える、請求項23記載の無線通信デバイス。
- 25前記情報単位は可変ビットレートデータストリームを備える、請求項23記載の無線通信デバイス。
- 26前記情報単位はマルチメディアデータを備える、請求項23記載の無線通信デバイス。
- 27前記情報単位はビデオデータを備える、請求項23記載の無線通信デバイス。
- 28前記情報単位はオーディオデータを備える、請求項23記載の無線通信デバイス。
- 29複数の情報単位を更に備える、請求項23記載の無線通信デバイス。
- 30前記複数の情報単位は一定のレートで発生する、請求項29記載の無線通信デバイス。
- 31前記複数の通信チャネルはCDMAチャネルである、請求項23記載の無線通信デバイス。
- 32前記複数の通信チャネルはGSMチャネルである、請求項23記載の無線通信デバイス。
- 33前記複数の通信チャネルはGPRSチャネルである、請求項23記載の無線通信デバイス。
- 34前記複数の通信チャネルはEDGEチャネルである、請求項23記載の無線通信デバイス。
- 35複数の通信チャネルを受理するように構成された受信機と;前記の受理された複数の通信チャネルを受理しそして前記チャネルをデコードするように構成されたデコーダと、なおここでは、デコードされたチャネルはデータのマルチメディアストリームを生成するように蓄積される;を備え 、 前記デコーダは、さらに、情報単位スライスをデコードするように適合され、前記情報単位スライスのサイズは、前記通信チャネルの物理層データパケットサイズの1つを越えない、 無線通信デバイス。
- 36前記通信チャネルから受け取られたデータパケットのサイズは、前記エンコーダによって推定される、請求項 35 記載の無線通信デバイス。
- 37前記通信チャネルから受け取られたデータパケットのサイズは、更なるシグナリングにおいて示される、請求項 35 記載の無線通信デバイス。
- 38データの前記マルチメディアストリームは可変ビットレートデータストリームである、請求項 35 記載の無線通信デバイス。
- 39前記マルチメディアストリームはビデオストリームである、請求項 35 記載の無線通信デバイス。
- 40前記マルチメディアストリームは遠隔会議ストリームである、請求項 35 記載の無線通信デバイス。
- 41前記複数の通信チャネルはCDMAチャネルである、請求項 35 記載の無線通信デバイス。
- 42前記複数の通信チャネルはGSMチャネルである、請求項 35 記載の無線通信デバイス。
- 43前記複数の通信チャネルはGPRSチャネルである、請求項 35 記載の無線通信デバイス。
- 44前記複数の通信チャネルはEDGEチャネルである、請求項 36 記載の無線通信デバイス。
- 45データを符号化する方法を具現化するコンピュータ可読メディアであって、前記方法は、 利用可能な通信チャネル に使用 可能な物理層パケットサイズを決定することと;情報単位の間隔の間に発生する前記利用可能な通信チャネルの伝送の数を決定することと;前記情報単位に含まれるデータをスライスに区分することと、なおここでは、スライスの数は、前記情報単位の前記間隔の間の前記伝送の数以下であり、そして、前記スライスのサイズは、物理層パケットサイズを越えない;を含む、コンピュータ可読メディア。
- 46請求項1から請求項21までのいずれか1項に記載の方法の全てのステップを実行するためのコンピュータプログラム。
Independent claims46
129 paragraphs, as filed
(Claim of priority under 35 USC 119) This patent application is assigned to the assignee and expressly incorporated herein by reference, "Multimedia Packets Carried by" filed on May 13, 2004. Claims the priority of US Patent Provisional Application No. 60 / 571,673 entitled "CDMA Physical Layer Products)".
(Refer to the pending related patent application) This patent application relates to the following co-pending US patent application: "Delivery Of Information Over A Communication Channel" of agent reference number 030166UI, which is filed at the same time, transferred to the assignee, and explicitly incorporated herein by reference in its entirety; "Header Compression Of Multimedia" of agent reference number 030166U3, which is filed at the same time, transferred to the Transferee, and explicitly incorporated herein by reference in its entirety. Data Transmitted Over A Wireless Communication System) "; Synchronization Of Audio And Video Data In, "Synchronization Of Audio And Video Data In," at Agent Reference Number 030166U4, filed at the same time, transferred to the Transferee, and explicitly incorporated herein by reference in its entirety. A Wireless Communication System) ".
(Field) The present invention generally relates to the distribution of information on a communication system, and more specifically, divides information units so as to fit physical layer packets of a constant bit rate communication link (a constant bit rate communication link). It is related to partitioning).
(background) The demand for multimedia data distribution over various communication networks is increasing. For example, consumers want to deliver stream video over various communication channels, such as the Internet, wireline and wireless communication networks. Multimedia data can be in different formats and data rates, and different communication networks use different mechanisms for the transmission of real-time data over their respective communication channels.
One type of communication network that has become commonplace is mobile radio networks for wireless communication. Wireless communication systems have many applications, including, for example, mobile phones, paging, wireless local loops, personal digital assistants (PDAs), Internet telephonies, and satellite communication systems. A particularly important application is the cellular telephone systems for mobile subscribers. As used herein, the term "cellular" system includes both mobile phone frequencies and personal communications services (PCS) frequencies. Various over-the-air interfaces have been developed for such mobile phones, including frequency division multiple access (FDMA), time division multiple access (TDMA) and code division multiple access (CDMA). There is.
Different national and international standards have been established to support a variety of air interfaces, such as Advanced Mobile Phone Service (AMPS), Pan-European Digital Mobile Phones. Global System for Mobile (GSM), General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Provisional Standard 95 (IS-95) and its Derivatives, IS-95A, IS-95B, ANSI J-STD-008 (often collectively referred to here as IS-95), and new high data rate systems such as cdma2000, Universal Mobile Communications Service (Universal). Mobile Telecommunications Service (UMTS), Wideband CDMA (wideband) Includes CDMA) (WCDMA), etc. These standards are disseminated by the American Telecommunications Industry Association (TIA), the Third Generation Partnership Project (3GPP), the European Telecommunications Standards Institute (ETSI) and other well-known standards bodies.
Users, or customers of mobile wireless networks, such as mobile phone networks, want to receive streaming media, such as video, multimedia, and Internet Protocol (IP), over wireless communication links. For example, customers want to be able to receive stream video, such as teleconferences or television broadcasts, on their mobile phones or other portable wireless communication devices. Other examples of the types of data customers want to receive on their wireless communication devices include multimedia multicast / broadcast and Internet access.
There are different types of multimedia data sources, and different types of communication channels where it is desired to carry streaming data. For example, multimedia data sources can generate data at constant bit rate (CBR) or variable bit rate (VBR). In addition, the communication channel can carry data via CBR or VBR. Table 1 below lists the various combinations of data sources and communication channels.<tables num="1"><img file="JP4448171B2_D0001.tif" /></tables>
Communication channels typically carry in chunks of data in chunks that we call physical layer packets or physical layer frames. The data generated by a multimedia source may be a continuous stream of bytes, such as a voice signal encoded using mu-law or A-law. .. More often, the data generated by multimedia sources is in groups of bytes called data packets. For example, an MPEG-4 video encoder compresses visual information as a sequence of pieces of information that we call video frames here. Visual information is typically encoded by an encoder at a fixed video frame rate, typically 25 or 30 Hz, and must be rendered by a decoder at the same rate. Video frame period) is the time between two video frames and can be calculated as the reciprocal of the video frame rate, for example, a 40 ms video frame period corresponds to a 25 Hz video frame rate. Each video frame is encoded into a variable number of data packets, and all data packets are transmitted to the decoder. If a portion of a data packet is lost, the packet becomes unusable by the decoder. On the other hand, if some of the data packets are lost, the decoder can reconstruct the video frame, but at the cost of some quality degradation in the resulting video sequence. Each data packet therefore contains a portion of the description of a video frame, and the number packets can therefore change from one video frame to another.
If the source produces data at a fixed bit rate and the communication channel transmits data at a fixed rate, then assuming that the communication channel data rate is at least as fast as the source data rate, or if two data rates are so. If not matched, communication system resources are used efficiently. In other words, if the fixed data rate of the source is the same as the fixed data rate of the channel, then the resources of the channel can be fully utilized and the source data can be transmitted without delay. it can. Similarly, if the source produces data at a variable rate and the channel transmits at a variable rate, and as long as the channel data rate can support the source data rate, then the two data rates can match. And again, the resources of the channel are fully utilized and all of the source data can be transmitted without delay.
If the source produces data at a fixed data rate and the channel is a variable data rate channel, then channel resources may not be used as efficiently as possible. For example, in this improperly combined case, the statistical multiplexing gain (SMG) is less than the CBR source on the matched CBR channel. Statistical multiplexing gain occurs when the same communication channel can be used or multiplexed among multiple users. For example, when a communication channel is used to transmit voice, the speaker usually does not speak continuously. That is, silence (listening) will follow the outburst of "talk" from the speaker. If the "talk" to silence time ratio is, for example 1: 1, then on average the same communication channel could be multiplexed and support two users. Will be able to. However, if the data source has a fixed data rate and is delivered on a variable rate channel, there is no SMG because there is no time for the communication channel to be used by another user. That is, there is no break during the "silence" of the CBR source.
The last case noted in Table 1 above is that the source of the multimedia data is a variable bit rate stream, such as a multimedia data stream such as video, and it has a constant bit rate allocation. It is a situation where transmission is performed on a communication channel having a fixed bit rate, such as a radio channel. In this case, delays are typically introduced between the source and the communication channel, creating "spurts" of data so that the communication channel can be used efficiently. In other words, the variable rate data stream is stored in the buffer and delayed long enough so that the output of the buffer can be taken out to fit the channel where the data rate is fixed. The buffer needs to store or delay enough data so that it can maintain a constant output without "emptying" the buffer, and as a result, the CBR communication channel is fully utilized. Communication channel resources are not wasted.
The encoder periodically generates video frames according to the video frame period. A video frame consists of data packets (consist of), and the total amount of data in the video frame is variable. The video decoder must draw the video frame at the same video frame rate used by the encoder to ensure acceptable results for the viewer. Transmission of a video frame with a variable amount of data at a fixed video frame rate and over a fixed rate communication channel can result in inefficiency. For example, if the total amount of data in a video frame is too large to be transmitted within the video frame period at the channel bit rate, then the decoder will draw it in time according to the video frame rate. You may not be able to receive all frames. In fact, traffic shaping buffer (traffic shaping) buffer) is used to smooth out such large fluctuations for delivery over fixed rate channels. If the fixed video frame rate is planned to be maintained by the decoder, this will cause a delay in drawing the video.
Another problem is that if data from multiple video frames is contained in a single physical layer packet, then the loss of the single physical layer packet results in degradation of multiple video frames. is there. Loss of one physical layer packet can result in degradation of multiple video frames, even when the data packet is close to the physical layer packet size.
Therefore, there is a technical need for techniques and devices that can improve the transmission of variable data rate multimedia data over wireless communication channels.
[wrap up] The embodiments disclosed herein address the needs set forth above in order to improve the transmission of information over wireless communication channels. These techniques involve determining the number of transmissions in a wireless communication system that occur during an interval, or period an information unit. Information units are partitioned into portions, or slices), where the number of slices is less than or equal to the number of transmissions between information unit intervals. Another aspect is determining the available communication channels for transmitting information and the possible physical layer packet size of the available channels. The unit of information is divided into parts or slices, where the size of the part is chosen so that it does not exceed one of the physical layer packet sizes of the available communication channels. The technology can be used for various types of information such as multimedia data, variable bit rate data streams, video data or audio data. The technology also offers a variety of wireless interfaces such as Pan-European Digital Mobile Phone System (GSM), General Packet Radio Service (GPRS), Extended Data GSM Environment (EDGE) or TIA / EIA-95-B (IS-95), It can also be used with CDMA-based standards such as TIA / EIA-98-C (IS-98), IS2000, HRPD, cdma2000, Broadband CDMA and others (WCDMA), and others.
Another aspect includes and describes techniques for transmitting multimedia data over wireless communication systems. These techniques include determining the available communication channels for transmitting multimedia data and determining the available data packet size for the available channels. Frames of multimedia data are divided into sections called "slices", where the slice size is chosen to match one of the available communication channel data packet sizes. To. The phrase "multimedia frame" for video used here. "frame)" means a video frame that can be displayed / rendered on the display device after decoding. Video frames can be further subdivided into independently decodable units. In video jargon, these are called "slices." In the case of audio and speech, as used herein, the term "multimedia frame", speech or audio time window (a time window) information in which o is compressed for decoding the transmission and receiver means. The phrase "information unit interval" used herein refers to the time duration of the multimedia frame described above. For example, in the case of video, the information unit interval is 100 milliseconds for 10 frames / second video. Further, as an example, in the case of speech, the information unit interval is typically 20 milliseconds in cdma2000, GSM and WCDMA. From this description, audio / speech It is clear that frames are usually not further divided into independently decodable units, and video frames are usually divided into independently decodable slices. The terms "multimedia frame", "information unit spacing", etc. are apparent from the context when referring to multimedia data for video, audio and speech.
Another aspect is determining the number of channel transmissions that occur during the information unit interval and then dividing the information unit into multiple parts or slices that correspond to the number of transmissions during the information unit interval. , And assigning each slice to the corresponding transmission. For example, if the communication system is a time slot communication system and the data transmission is divided into physical layer packets transmitted at a given interval or time slot, then at the information unit interval. The number of corresponding time slots is determined. The information unit is then divided into a number of slices equal to the number of time slots that occur during the information unit interval. Slices are then assigned to physical layer packets transmitted during the corresponding time slot. On the other hand, the information unit partitions, or slices, are sized to match the physical layer packet size they carry during the time slot.
On the other side, time slots assigned to a plurality of information units can be shared among the units. For example, a time slot that occurs between two consecutive information unit intervals can be shared between these two information units. That is, if one of the information units contains more data than the other, then the time slot that would normally be assigned to the smaller information unit may be assigned to the larger information unit. it can. In this way, individual information units may use additional time slots for the transmission of information, but the average rate of the information units can be maintained, thereby the peak rate (or given information). Increase the maximum size of the unit). Such an approach is beneficial in improving the visual quality by allowing I-frames to be larger than P-frames.
The technology can also be used with a variety of wireless interfaces. For example, the technology is Pan-European Digital Mobile Phone System (GSM), General Purpose Packet Radio System (GPRS), Extended Data GSM Environment (EDGE), or TIA / EIA-95-B (IS-95), TIA / EIA- It can be used with CDMA based standards such as 98-C (IS-98), IS2000, HRPD, cdma2000, wideband CDMA and others (WCDMA), and others.
The technique can be used for various types of information. Examples of the types of information for which the present technology can be used include variable bit rate data streams, multimedia data, video data, or audio data.
Other features and advantages of the invention are evident from the following description of exemplary embodiments that illustrate aspects of the invention as an example.
[Detailed description] The term "exemplary" as used herein means "an example, an instance, or an illustration." Any embodiment described herein as "exemplary" should not necessarily be construed as preferred or advantageous over other embodiments.
The term "streaming" as used herein refers to essentially continuous multimedia data on a dedicated or shared channel in an interactive unicast or broadcast application, such as audio, speech or video information. Means real time delivery. The term "multimedia frame" for video used herein means a video frame that can be displayed / drawn on a display device after decoding. Video frames can be further divided into independently decodable units. In video jargon, these are called "slices." In the case of audio and speech, the term "multimedia frame" as used herein means information in a time window in which the speech or audio is compressed for transmission and decoding at the receiver. To do. The phrase "information unit" used here. "Interval)" represents the time duration of the multimedia frame described above. For example, in the case of video, the information unit interval is 100 milliseconds for 10 frames / second video. Furthermore, as an example, in the case of speech, the information unit interval is typically 20 milliseconds in cdma2000, GSM and WCDMA. From this description, it is clear that audio / speech frames are usually not further divided into independently decodable units, and video frames are usually further divided into independently decodable slices. is there. The terms "multimedia frame", "information unit spacing", etc. are apparent from the context when referring to multimedia data for video, audio and speech.
Techniques for improving the transmission of information over wireless communication channels will be described. These techniques include determining the number of transmissions in a wireless communication system that occur during an information unit interval. The data in the information unit is divided into slices, where the number of slices is equal to or less than the number of transmissions during the information unit interval. Another aspect is determining the available communication channels for transmitting information and the possible physical layer packet size of the available channels. The information unit is divided into slices, where the size of the slice is chosen so that it does not exceed one of the physical layer packet sizes of the available communication channels. The technology can be used for various types of information such as multimedia data, variable bit rate data streams, video data, or audio data. The technology also offers a variety of wireless interfaces, such as Pan-European Digital Mobile Phone System (GSM), General Packet Radio Service (GPRS), Extended Data GSM Environment (EDGE), or TIA / EIA-95-B (IS-95). ), TIA / EIA-98-C (IS-98), IS2000, HRPD, cdma2000, CDMA based standards such as Broadband CDMA (WCDMA), and others.
In one embodiment, the technology is used to transmit multimedia data over a wireless communication system. These techniques include determining the available communication channels for transmitting multimedia data and determining the available data packet size for the available channels. The frame of multimedia data is divided into parts called "slices", where the size of the slice is chosen so that it does not exceed one of the data packet sizes of the available communication channels. By choosing the size of the slice so that it does not exceed the size of the available communication channel, the size of the slice is "matched" to the size of the channel.
The technique described is to determine the number of channel transmissions that occur during an information unit interval or period, and then divide the information unit into parts or slices of numbers that correspond to the number of transmissions during the information unit interval. It involves partitioning and assigning each slice to the corresponding transmission. For example, if the communication system is a timeslot communication system and the data transmission is divided into physical layer packets transmitted at a given interval or timeslot, then the timeslot corresponding to the information unit interval or period. The number of is determined. The information unit is then divided into a number of slices equal to the number of time slots that occur during the information unit interval. Slices are then assigned to physical layer packets transmitted during the corresponding time slot. On the other hand, the information unit divisions or slices are sized to fit the physical layer packet size transmitted during the time slot.
Time slots assigned to a plurality of information units can be shared among the respective units. For example, a time slot that occurs between two consecutive information unit intervals can be shared between these two information units. That is, if one of the information units contains more data than the other, then the time slot normally assigned to the smaller information unit can be assigned to the larger information unit. In this way, individual information units may use additional time slots for the transmission of information, but the average rate of the information units can be maintained, thereby the peak rate (or given information). Increase the maximum size of the unit). Such an approach is beneficial in improving the visual quality by allowing I-frames to be larger than P-frames.
In general, an information source has a variable entropy, i.e., it produces a unit of information that contains different amounts of data. Information sources can generate units of information at a constant or predetermined rate. In addition, the information unit may be called a frame.
Examples of protocols and formats for transmitting information such as variable bit rate data, multimedia data, video data, speech data, or audio data from content servers or sources over wired networks to mobile are also provided. To. The technique described is applicable to any type of multimedia application, such as unicast streaming, interactive and broadcast streaming applications. For example, the technology provides multimedia applications such as broadcast / multicast services, or audio and interactive services such as video phones between two mobiles, as well as video data (eg, wireless streaming to wireless mobiles). It can also be used to transmit multimedia data such as (such as content servers).
FIG. 1 shows a communication system 100 configured according to the present invention. Communication system 100 includes infrastructure 101, multiple wireless communication devices (WCD) 104 and 105, and terrestrial communication line communication devices 122 and 124. WCD will also be called Mobile Station (MS) or Mobile. In general, the WCD may be mobile or fixed. Terrestrial communication devices 122 and 124 can include serving nodes or content servers that provide various types of multimedia data, such as streaming data. In addition, the MS can transmit streaming data such as multimedia data.
Infrastructure 101 may also include other components such as base station 102, base station controller 106, mobile exchange 108, switching network 120, and the like. In one embodiment, the base station 102 is integrated with the base station controller 106, and in other embodiments, the base station 102 and the base station controller 106 are separate components. Different types of switching networks 120, such as IP networks, or public switched telephone networks (PSTNs), may be used to send signals in communication system 100.
The term "forward link" or "downlink" refers to the signal path from Infrastructure 101 to MS, and the term "reverse link" or "uplink". "link)" refers to the signal path from the MS to the infrastructure. As shown in FIG. 1, MS104 and 105 receive signals 132 and 136 on the forward link and transmit signals 134 and 138 on the reverse link. Generally, the signals transmitted from the MS 104 and 105 are intended to be received by another communication device, such as another remote unit, or terrestrial communication line communication devices 122 and 124, and pass through an IP network or a switching network 120. Will be sent. For example, if the signal 134 transmitted from the starting WCD (initiating WCD) 104 is the destination MS (destination). If intended to be received by MS) 105, the signal is sent through infrastructure 101 and signal 136 is sent over the forward link to the destination MS 105. Similarly, signals initiated in infrastructure 101 may be broadcast to MS105. For example, the content provider may send multimedia data, such as streaming multimedia data, to the MS105. Typically, a communication device such as an MS or terrestrial line communication device can be both an initiator and a destination of the signal.
Examples of MS104 include mobile phones, wirelessly communicable personal computers, and personal digital assistants (PDAs), and other wireless devices. Communication system 100 may be designed to support one or more wireless standards. For example, the standards are Pan-European Digital Mobile Phone System (GSM), General Packet Radio Service (GPRS), Extended Data GSM Environment (EDGE), TIA / EIA-95-B (IS-95), TIA / EIA-98. -C (IS-98), IS2000, HRPD, cdma2000, standards called Broadband CDMA (WCDMA), and others may be included.
FIG. 2 is a block diagram illustrating an exemplary packet data network and various air interface options for delivering packet data over a wireless network. The techniques described can be implemented in packet-switched data networks such as those illustrated in Figure 2. As shown in the example of FIG. 2, the packet-switched data network system includes a radio channel 202, multiple recipient nodes or MS204, a sending node or content server 206, a serving node 208, and a controller. 210 may be included. The transmitting node 206 can be coupled to the serving node 208 via a network 212 such as the Internet.
The serving node 208 may include, for example, a packet data serving node (PDSN) or a serving GPRS support node (SGSN) or a gateway GPRS support node (GGSN). The serving node 208 can receive packet data from the transmitting node 206 and supply a packet of information to the controller 210. The controller 210 may include, for example, a base station controller / packet control function (BSC / PCF) or a radio network controller (RNC). In one embodiment, the controller 210 communicates with the serving node 208 on a Radio Access Network (RAN). The controller 210 communicates with the serving node 208 and transmits a packet of information over the radio channel 202 to at least one recipient node 204, such as the MS.
In one embodiment, the serving node 208 and / or transmitting node 206 may also include an encoder for encoding the data stream, a decoder for decoding the data stream, or both. For example, an encoder could encode a video stream, thereby generating variable-sized frames of data, and a decoder could generate variable-sized frames of data. You will be able to receive and decode them. Since the frames are of various sizes but the video frame rate is constant, a variable bit rate stream of data is generated. Similarly, the MS may include an encoder for encoding the data stream, a decoder for decoding the received data stream, or both. The term "codec" is used to describe a combination of encoder and decoder.
In one example illustrated in FIG. 2, data such as multimedia data is delivered from a transmit node 206, which is connected to a network or Internet 212, to a receiver node, or MS204, a serving node, or a packet data serving node ( It can be sent via PDSN) 206 and the controller, or base station controller / packet control function (BSC / PCF) 208. The radio channel 202 interface between the MS204 and the BSC / PCF210 is an air interface and typically uses many channels for signaling and bearers, or payloads, data. be able to.
(Air interface) The air interface 202 can be operated according to any of many wireless standards. For example, the standard is a standard based on TDMA or FDMA, such as Pan-European Digital Mobile Phone System (GSM), General Line Radio Service (GPRS), Extended Data GSM Environment (EDGE), or TIA / EIA-95- CDMA-based standards such as B (IS-95), TIA / EIA-98-C (IS-98), IS2000, HRPD, cdma2000, wideband CDMA (WCDMA), and others can be included.
In systems based on cdma2000, data is distributed on multiple channels, for example, on the basic channel (FCH), commonly used for transmitting audio, on the dedicated control channel (DCCH), on the auxiliary channel (SCH), and It can be transmitted on a packet data channel (PDCH) and, of course, on other channels.
The FCH provides a communication channel for transmitting speech at multiple fixed rates, such as full rate, half rate, 1/4 rate and 1/8 rate. When the FCH provides these rates and the user's speech activity requires a rate less than the full rate to achieve the desired voice quality, the system chooses one of the lower data rates. Use to reduce interference with other users in the system. The advantage of lowering the source rate to increase system capacity is well known in CDMA networks.
DCCH is similar to FCH, but at one of two fixed rates, 9.6kbps in radio configuration three (RC3), and radio configuration five (RC5). At 14.49, it provides only full rate traffic. This is called the lx traffic rate. SCH can be configured in cdma2000 to provide traffic rates at lx, 2x, 4x, 8x and 16x. Can be configured to provide a traffic rate to. When there is no data to be transmitted, to ensure reduced interference with other users in the system, or to transmit power of the base station transmitter. To stay within the budget), both DCCH and SCH can stop transmission, do not transmit any data, and are also called dtx. PDCH can be configured to carry data packets that are n * 45 bytes, where n = {1, 2, 4, 8}.
The FCH and DCCH channels provide constant delay and low data packet loss for data communication, for example to enable interactive services. The SCH and PDCH channels provide multiple constant bit rate channels that provide higher bandwidth than FCH and DCCH, such as 300kbps to 3Mbps. SCH and PDCH also have variable delays as these channels are shared among many users. In the case of SCH, multiple users are multiplexed in time, which results in different amounts of delay depending on the system load. In the case of PDCH, bandwidth and delay depend on, for example, radio status, negotiated quality of service (QoS) and other scheduling considerations. Similar channels are available in systems based on TIA / EIA-95-B (IS-95), TIA / EIA-98-C (IS-98), IS2000, HRPD, UMTS, and Broadband CDMA (WCDMA). is there.
It is noteworthy that the FCH offers multiple fixed bit data rates (full, half, 1/4 and 1/8) to save the power required by voice users. Typically, voice encoders or vocoders will use lower data rates when the time-frequency structure of the signal to be transmitted allows for higher compression without unnecessarily compromising quality. .. This technique is commonly referred to as source controlled variable bit rate vocoding. Thus, in systems based on TIA / EIA-95-B (IS-95), TIA / EIA-98-C (IS-98), IS2000, HRPD, UMTS, cdma2000, or wideband CDMA (WCDMA), There are multiple constant bit rate channels available for transmitting data.
In CDMA-based systems such as cdma2000, communication channels are divided into "slots" continuous streams. For example, the communication channel can be divided into 20ms segments or time slots. This is also referred to as the "Transmit Time Interval" (TTI). The data transmitted between these time slots is assembled into packets, where the size of the data packets depends on the available data rate or bandwidth of the channel. Therefore, it is possible that there are individual data packets being carried on their respective communication channels during any individual time slot. For example, during a single time slot, data packets can be transmitted on the DCCH channel, and different data packets can be transmitted simultaneously on the SCH channel.
Similarly, in GSM, or GPRS, or EDGE-based systems, data can be transmitted between BSC208 and MS204 using multiple time slots within a frame. FIG. 3 is a block diagram showing two radio frames 302 and 304 in a GSM air interface. As shown in FIG. 3, the GSM air interface radio frames 302 and 304 are each divided into eight time slots. Individual time slots are assigned to specific users in the system. In addition, GSM transmission and reception use two different frequencies, and forward and reverse links are offset by three time slots. For example, in FIG. 3, the downlink radio frame 302 is at time t.<sub>0</sub>It will start at and be transmitted at one frequency, and the uplink radio frame 304 will start at a later time and be transmitted at a different frequency. The downlink radio frame 302 is offset from the uplink radio frame by three time slots, the TSO-TS2. Having an offset between the downlink and uplink radio frames allows the wireless communication device or terminal to operate without having to be able to transmit and receive at the same time.
Advances in GSM wireless communication devices or terminals have resulted in GSM terminals capable of receiving multiple time slots during the same wireless frame. These are called "multislot classes" and can be found in Appendix B of 3GPP TS 45.002, which are incorporated here as a whole. Thus, in a system based on GSM, GPRS, or EDGE, there are multiple fixed time slots available for transmitting data.
(Packet data network model) FIG. 4 is a diagram showing a protocol stack for packet data in a wireless communication system. Application data from the encoder / decoder (codec) 402 at host 404 is encapsulated in RTP / UDP / IP / PPP layer 406 for IP transmission according to conventional OSI layering methods. The data goes through the OSI layer of the PDSN 206 and wireless network (RN) 208, such as the base station controller / packet control function, to the MS204, where the codec 410 decompresses the data.
Multimedia encoders, such as video encoders, can generate variable size multimedia frames. For example, in some image compression techniques such as MPEG-4, each new video frame contains information used to display the next frame in the video sequence. In systems based on this type of technology, video frames can typically be of two types: I or P frames. I-frames are self-contained and similar to JPEG files in that each I-frame contains all the information needed to display one complete frame. In contrast, a P-frame typically, like a moving image, contains information to be compared to a previous frame, such as differential information to the previous frame. Therefore, the P frame is not self-contained, that is, it self-decodes (be) because the P frame depends on the previous frame. self-decoded) cannot. Typically, I-frames are larger than P-frames, eg, about 8-10 times larger, depending on the content and encoder settings.
Below are some typical syntax elements for video frames. There are subtle differences between different codecs, such as H.263, H.263 +, MPEG-4, and AVC / H.264, but such differences are important to the techniques described. Not relevant. FIG. 5 shows a coded video stream of video frame 502 that identifies different parts of the stream using typical syntax. start_code (SC) 504: Since each video frame starts with a unique pattern, the start of the video frame can be identified in the bitstream. The term start_code is commonly used to mean "video frame start code" because there are many types of start codes. Frame_Header (FH) 506: A sequence of bits that specifies the interpretation of the rest of the payload. Among other things, the header contains timing information (in MPEG-4, these fields are called modulo_time_base and vop_time_increment). Video_packet / Slice 508: A collection of one or more microblocks that form an area of an independently decodable video frame. Resync_marker (RM) 510: A unique sequence of bits that allows a compliant decoder to locate the beginning of a video_packet. Slice_header (S) 512: A sequence of bits that specifies the interpretation of the rest of the payload in a given slice or video packet. In particular, the slice header contains the address of the first macroblock in the video frame. For example, in a 176x144 pixel QCIF size frame, arranged as a 16x16 pixel 11x9 macroblock, the macroblock "11" would be in the second (second) row and first (first) column columns.
The video packet or slice 508 may be variable length or size and is typically encoded using variable length code (VLC). After transmission, the received slice is decoded. If a decoding error occurs for any macroblock in slice 508, for example due to a channel error, not all of the remaining macroblocks in slice 508 may be properly decoded. unknown. Appropriate decoding may be restarted after positioning resync_marker510 or start_code512 in the bitstream. A technique to address this issue is included in MPEG-4, which allows the use of reversible VLC (RVLC), where, after discovering the resync_marker or start_code, the macroblocks are reversed in reverse order. By decoding, some macroblocks can be decoded from the previous slice 508 in the stream. RVLC adds coding overhead and complexity, and is not commonly used in many applications, such as video, and any quality improvement is still valued in the presence of block errors.
To overcome some of these problems, in one embodiment, each video slice can be decoded independently, and the video slice size is that it is the size of the physical layer data packet. Selected and encoded to fit. That is, the video slice size is constrained so that the encoded slice contains the same or fewer data bits as the physical layer data packet of the available communication channel. Further, as described below, it is convenient to constrain the encoder so that the slice size matches the physical layer data packet size. Figure 6 shows a histogram of slice sizes for AVC / H.264 encoded video sequences when the maximum size is constrained or limited to 189 bytes. Note that encoders are generally not constrained to have a predetermined maximum slice size.
(VBR performance considerations) Variable bit rate (VBR) multimedia data, such as video, typically contains common characteristics. For example, video data is typically captured at a fixed frame rate by a sensor such as a camera. Multimedia transmitters generally require a finite processing time with an upper bound to encode a video stream. Multimedia receivers generally require a finite processing time with an upper bound to decode a video stream.
It is generally desirable to reconstruct multimedia frames at the same frame rate at which they were generated. For example, in the case of video, it is desirable to display a reconstructed video frame at the same rate as the video was captured by a sensor or camera. Having the same rebuild and capture rate makes it easier to synchronize with other multimedia elements, for example, synchronizing a video stream with an accompanying audio, or speech, stream is simplified.
In the case of video, it is usually desirable to maintain a consistent level of quality from the perspective of human perception. For a person, processing a multimedia stream with varying qualities is generally more cumbersome and burdensome than processing a multimedia stream of uniform quality. For example, processing a video stream that contains quality artifacts such as freeze frame and "blockiness" is usually awkward for humans.
FIG. 7 shows the various levels of encapsulation that exist when transmitting multimedia data such as video data over wireless links that use the RTP / UDP / IP protocol. As shown in FIG. 7, the video codec produces a payload 702 that contains information that describes the video frame. Payload 702 consists of several video packets (not drawn). Payload 702 can be pre-pended by Slice_Header (SH) 704. Thus, the application layer data packet 705 includes the payload 702 and the associated Slice_Header 704. Further header information can be added as the payload traverses a network such as the Internet. For example, a real-time protocol (RTP) header 706, a user datagram protocol (UDP) header 708, and an internet protocol (IP) header 710 may be added. These headers provide the information used to send the payload from its source to its destination.
Upon entering the wireless network, the point-to-point protocol (PPP) header 712 provides framing information for serializing packets into a continuous stream of bits. Will be added. A wireless link protocol, such as RLP in cdma2000 or RLC in W-CDMA, then packs a stream of bits into RLP packet 714. The wireless link protocol allows, among other things, the retransmission and rearrangement of packets sent over an air interface. Finally, the air interface MAC layer takes one or more RLP packets 714, compresses them into MUX layer packets 716, and adds a multiplexing header (MUX) 718. The physical layer packet channel coder then decodes the error (decoding). Add a checksum (CRC) 720 to detect errors and a tail part 722 to form the physical layer packet 725.
Consecutive uncoordinated encapsulation shown in Figure 7. encapsulation) has several consequences on the transmission of multimedia data. One such result is that there may be a mismatch between the application layer data packet 705 and the physical layer packet 725. As a result of this nonconformity, every time a physical layer packet 725 containing a portion of one or more application layer packets 705 is lost, the entire corresponding application layer 705 is lost. Losing one physical layer packet 725 is an application tier data packet 705 because a portion of a single application tier data packet 705 may be contained in more than one physical layer data packet 725. This can result in the loss of the entire application layer packet 705 as it is necessary for the entire application to be properly decoded. Another result is that if more than one portion of the application layer packet is contained within the physical layer data packet 725, then a single physical layer data packet 725 loses more than one application layer data. The result is the loss of packet 705.
FIG. 8 is a diagram illustrating an example of conventional allocation of an application data packet 705 to a physical layer data packet 725, such as a multimedia data packet. Figure 8 shows two application data packets 802 and 804. The application data packet can be a multimedia data packet, for example, each data packet 802 and 804 can represent a video frame. The uncoordinated encapsulation illustrated in FIG. 8 can result in a physical layer packet with data from a single application data packet or from more than one application data packet. As shown in FIG. 8, the first physical layer data packet 806 can contain data from a single application layer packet 802, while the second physical layer data packet 808 is more than one application data packet. It can contain data from 802 and 804. In this example, if the first physical layer data packet 806 is "lost" or corrupted during transmission, then a single application layer data packet 802 is lost. On the other hand, if the second physical layer packet 808 is lost, then the two application data packets 802 and 804 are also lost.
(Explicit bit rate control) The use of a technique called explicit bit rate control (EBR) can improve the transmission of information units over CBR channels rather than Rather that CBR or VBR. In EBR, an information unit, such as a video stream, is partitioned so that the application layer data packet of the information unit matches the physical layer data packet of the communication channel on which the data is to be transmitted. For example, in EBR, the encoder can be constrained or configured so that each application layer data packet it outputs is of the desired size and can be decoded independently.
Examples of EBR technologies, such as those implemented on CDMA based communication systems, such as cdma2000 based communication systems, will be described. Communication systems based on cdma2000 include multiple channels that carry data, three examples being a dedicated control channel (DCCH), an auxiliary channel (SCH), and a packet data channel (PDCH). DCCH is an on / off, low rate, channel, dedicated to a single user. A SCH is a variable, high rate, scheduled channel that may be shared among multiple users. SCH is called a "variable" rate, but it is not a true "variable rate" channel, instead it has multiple fixed rates that can be selected. PDCH is a variable, high rate channel that is shared among multiple users. The following is an example of EBR using DCCH and SCH, and another example of EBR using PDCH.
(EBR using DCCH and V-SCH) In one embodiment of EBR, DCCH and SCH channels are utilized to carry multimedia data. FIG. 9 shows some characteristics of a time slot communication system based on cdma2000. In a system based on cdma2000, data is transmitted in time slot 902, for example in a 20ms time slot. When transmitting multimedia data, the time slot nature of the communication channel (the time slot) nature) can be used. For example, if a multimedia data stream, such as a video data stream, is transmitted at a rate of 10 frames per second (fps), then the entire frame of data must be transmitted within 100 ms. Therefore, five 20ms time slots 904,906, 908,910, and 912 can be used to carry a single frame of video data. Notably, in cdma2000 based systems, there are multiple channels available to carry data between each time slot. In one example shown in Figure 9, two possible channels, DCCH and, with different physical layer packet sizes, can be used to carry data within each individual time slot. There is SCH. In addition, data can be transmitted using a combination of DCCH and SCH channels, or data cannot be transmitted and is called "dtx". Thus, there are four possible physical layer packet sizes that can be used to carry data within each time slot, resulting in different data rates.
In one embodiment, the multimedia data frame is divided into "slices" containing at least one macroblock. For example, a video frame can be divided into macroblocks that are 16 pixels x 16 pixels. Macroblocks can then be grouped into slices. The size of the slices can be constrained to fit the physical layer packet size of the communication channels they are available. That is, the application layer frame is partitioned so that the slice does not occupy more than one physical layer packet size of the available communication channels.
For example, as mentioned above, in systems based on MPEG-4 compression technology, video frames may typically be two types, I or P frames. In general, each frame of data can be divided into slices so that each slice can be decoded independently. That is, each slice can be decoded without the need for other information. Each encoded slice is configured so that the size of the encoded slice matches the available size of the communication channel physical layer data packet. Also, if additional header information needs to be added to the multimedia data as it is encoded, the header size will be taken into account when choosing the slice size. For example, as shown in FIGS. 5 and 7, if the encoder is then encoding video information, each slice can include a slice header that is part of the application layer data packet. Thus, the slice size, including any header, can be configured such that the size of each encoded video slice matches the available size of the physical layer packet. In other words, the frame slice size fits the physical layer packet size.
Since each slice of the frame can be decoded independently, then the loss of one slice of the frame will not interfere with the decoding of the other slices of the frame. For example, if a video frame is divided into 5 slices so that each slice is independently decodable and fits the physical layer data packet, then one of the physical layer data packets is corrupted, or The loss will result in the loss of only the corresponding slice, and the slices that are successfully transmitted can be successfully decoded. Thus, the entire video frame may not be decoded, but that part can. In this example, 4 out of 5 video slices will be successfully decoded, which reduces performance but causes or displays video frames. Will make it possible.
For example, in a system based on cdma2000, if a 10fps video data stream is transmitted from the transmitting node to the MS, then each video frame can be divided into 5 slices. The number of slices in which a frame can be split corresponds to the number of time slots corresponding to the frame rate. In other words, at a 10fps rate, the frame period is 100msec. For a time slot period of 20 msec, there are five time slots transmitted during each frame period. Streaming data by adapting to the number of slices in which the frame is segmented, and constraining each slice size to match one of the available physical layer packet sizes of the available communication channels. Can be efficiently transmitted over a set of CBR channels that, in combination, act like VBR communication channels.
An example of a cdma2000 based system is described using DCCH and SCH channels. As mentioned above, DCCH channels can be configured to support multiple, fixed, data rates. For example, DCCH can support data transmission rates of 9.60 kbps or 14.4 kbps, respectively, depending on the selected rate set (RS), RS1 and RS2, respectively. The SCH channel can also be configured to support multiple, fixed data rates, depending on the SCH radio configuration (RC). SCH supports multiples of 9.6kps when configured as RC3 and multiples of 14.4kps when configured as RC5.
The SCH data rates are: SCH<sub>DATA_RATE</sub>= (n * RC data rate) Equation 1 However, n = 1, 2, 4, 8, or 16 (depending on the channel configuration)
Table 2 below shows the possible physical layer data packet sizes for DCCH and SCH channels in a cdma2000 based communication system. The first column identifies the case, that is, the possible configurations. The second and third columns show the DCCH rate set and SCH radio configuration, respectively. The fourth column has three items. The first is the physical layer data packet size of the 20ms time slot for the DCCH channel. The second item is the physical layer data packet size of the 20ms time slot for the SCH channel. The third item is the physical layer data packet size of the 20ms time slot for the DCCH and SCH channel combination.<tables num="2"><img file="JP4448171B2_D0002.tif" /></tables>
It should be considered if the application layer data packet is too large to fit the DCCH or SCH physical layer data packet and instead a combined DCCH plus SCH packet is to be used. It should be noted that there are trade-offs. Decide to encode the application tier data packet so that it is sized to fit a combined DCCH plus SCH data packet size, vs. two. The trade-off in making packets is that larger application layer packets or slices generally result in better compression efficiency, while smaller slices generally result in better error recovery. It brings resiliency). For example, larger slices generally require less overhead. Referring to FIG. 7, each slice 702 has its own slice header 704. Thus, if two slices are used instead of one, there are two slice headers attached to the payload, resulting in more data being needed to encode the packet, and therefore Reduces compression efficiency. On the other hand, if two slices are used, one is transmitted over DCCH and the other is transmitted over SCH, then only one of the DCCH or SCH data packets is corrupted or lost. It still allows recovery of other data packets, resulting in improved error resilience.
The derivations of Cases 1 and 9 are described in detail to aid in the understanding of Table 2. In Case 1, DCCH is configured as RS1 corresponding to a data rate of 9.6 Kbps. Since the channel is divided into 20ms time slots, within each time slot, the amount of data that can be transmitted on the RSI configured DCCH (DCCH configured RSI), or the physical layer packet size, is: 9600 bits / sec * 20 ms = 192 bits = 24 bytes Expression 7 Only 20 bytes are available for application layer data packets, including slices and slice headers, for additional overhead added to physical layer packets, such as RLP for error correction. Therefore, the first item in the fourth column of Table 2 is 20 in the case of Case 1.
The SCH for Case 1 is configured as 2x in RC3. RC3 corresponds to a basal data rate of 9.6Kbps, and 2X means that the channel data rate is twice the basal data rate. Therefore, within each time slot, the amount of data that can be transmitted on the 2x RC3 configuration SCH (SCH configured 2x RC3), or the physical layer packet size, is: 2 * 9 600 bits / sec * 20 ms = 384 bits = 48 bytes Expression 8 Here, only 40 bytes are available for the application layer data packet, including slices and slice headers, for additional overhead added to the physical layer packet. Therefore, the second item in the fourth column of Table 2 is 40 for Case 1. The third item in the fourth column of Table 2 for Case 1 is the sum of the first and second items, or 60.
Case 9 is similar to Case 1. In both cases, the DCCH is configured as RS1, which corresponds to a physical layer packet size of 20 bytes. The SCH channel in Case 9 is configured as 2xRC5. RC5 corresponds to a base data rate of 14.4Kbps, and 2X means that the channel data rate is twice the base data rate. Therefore, within each time slot, the amount of data that can be transmitted on the 2x RC5 configuration SCH (SCH configured 2x RC5), or the physical layer packet size, is: 2 * 14 400 bits / sec * 20 ms = 576 bits = 72 bytes Expression 2 Here, only 64 bytes are available for the application layer data packet, including slices and slice headers, for additional overhead added to the physical layer packet. Therefore, the second item in the fourth column of Table 2 is 64 in the case of Case 9.
The third item in the fourth column of Table 2 for Case 9 is the sum of the first and second items, or 84.
Other items in Table 2 were determined in a similar manner, where RS2 is a DCCH with a data rate of 14.4 Kbps, where 31 corresponds to 36 bytes in the 20 ms time slot available to the application layer. Corresponds to. It is noted that there is a dtx operation available in all cases, which is a zero payload size, where no data is transmitted on any channel. When user data can be transmitted in less than the available physical layer slots (20 ms each), dtx is used in the next slot and interferes with other users in the system. To reduce.
As illustrated in Table 2 above, a set of CBR channels can behave similarly to VBR channels by configuring the available fixed data rate channels, such as DCCH and SCH. That is, configuring a plurality of fixed rate channels allows the CBR channel to operate as a pseudo-VBR channel. Techniques that utilize pseudo-VBR channels determine the possible physical layer data packet size corresponding to the bit rate of the CBR channel from multiple available fixed bit rate communication channels, and encode a variable bit stream of data. By doing so, it produces multiple data packets such that each size of the data packet fits the size of one of the physical layer data packet sizes.
In one embodiment, the configuration of the communication channel is established at the beginning of the session and is then unchanged or only rarely changed throughout the communication session. For example, the SCH described in the above example is generally set to one configuration and stays in that configuration throughout the entire session. That is, the described SCH is a fixed rate SCH. In another embodiment, the channel configuration can be changed dynamically during the session. For example, a variable rate SCH (V-SCH) can change its configuration for each time slot. That is, during one time slot, the V-SCH can be configured with one configuration, such as 2xRC3, and in the next time slot, the V-SCH has a different configuration. It can be configured, for example, in 16xRC3 or other possible configurations of V-SCH. V-SCH can provide additional flexibility and improve the system performance of EBR technology.
If the communication channel configuration is fixed for all sessions, then the application layer packets or slices are selected to fit one of the available physical layer data packets. To. For example, if DCCH and SCH are configured as RS1 and 2xRC3, as shown in Case 1 in Table 2, then the application layer slice is 0 bytes, 20 bytes, 40 bytes, or 60 bytes. Will be selected to fit the packet. Similarly, if the channel is configured as RS1 and 16xRC3, as shown in Case 4 in Table 2, then the application layer slice can be 0 bytes, 20b bytes, 320 bytes, or 340 bytes. Selected to fit the packet. If the V-SCH channel was used, then it is possible to change between two different configurations for each slice. For example, if DCCH is configured as RS1 and V-SCH is configured as RC3, then the V-SCH configuration between 2xRC3, 4xRC3, 8xRC3, or 16xRC3, corresponding to Cases 1-4 in Table 2. It is possible to change to any of them. The choices between these various configurations are 0 bytes, 20 bytes, 40 bytes, 60 bytes, 80 bytes, 100 bytes, 160 bytes, 180 bytes, 320 bytes, as shown in Cases 1-4 in Table 2. It provides bytes, or 340 bytes of physical layer data packets. Therefore, in this example, using the V-SCH channel allows the application layer slice to fit into any of the 10 different physical layer data packet sizes listed in Cases 1-4 of Table 2. Allows you to be selected as.
Similar techniques can be used in wideband CDMA (WCDMA), which uses data channels (DCH). DCH, like V-SCH, supports different physical layer packet sizes. For example, DCH can support rates from 0 to nx in multiples of 40 octets, where "nx" corresponds to the maximum rate assigned to the DCH channel. Typical values for nx include 64kbps, 128kbps and 256kbps. In the case of WCDMA, the size of the packets delivered to the data is indicated using additional signaling using the Transport Format Combination Indicator (TFCI), so the MS is blind-detected. There is no need to do blind detection, and as a result, it reduces the computational burden on the MS when variable-sized packets are used, as in EBR. The EBR concept described in the present invention is an explicit indication of packet size similar to TFCI. It is applicable to both indication) and blind detection.
By selecting application tier data packets so that they fit the physical tier data packets, the combination of fixed bit rate communication channels and their aggregate data rate is similar to VBR communication channels. , And in some cases, it is capable of transmitting VBR data streams with better performance than VBR communication channels. In one embodiment, the variable bit rate data stream is encoded into a data packet stream sized to match the physical layer data packet size of the available communication channels and then transmitted in a fixed bit rate channel combination. Can be done. In another embodiment, the bit rate of the variable bit rate data stream changes so that it can be encoded into data packets of different sizes, and for different combinations of fixed bit rate channels to carry the data packets. May be used.
For example, different frames of video data may be of different sizes, so different combinations of constant bit rate communication channels can be selected to accommodate the transmission of video frames of different sizes. In other words, the variable bit rate data is constant by allocating the data packet to at least one of the fixed bit rate communication channels so that the total bit rate of the fixed bit rate communication channel matches the bit rate of the variable bit rate stream. It can be efficiently transmitted on the bit rate channel of.
Another aspect is that the encoder can be constrained to limit the total number of bits used to represent a variable bit rate data stream to the maximum number of preselected bits. That is, if the variable bit rate data stream is a frame of multimedia data such as video, the frame can be split into slices, in which case the slices are decoded independently for each slice. And the number of bits in the slice is chosen to be limited to a predetermined number of bits. For example, if the DCCH and SCH channels are configured on RS1 and 2xRC3 (configured RS1 and 2xRC3) (Case 1 in Table 2), then the slice is 20 bytes, 40 bytes, or 60 bytes. What is encoded can be constrained so that it is no greater than any of the above.
In another embodiment, the EBR can be used to carry multimedia data and the cdma2000 packet data channel (PDCH) can be used. PDCH can be configured to carry data packets that are n * 45 bytes, yet n = {1, 2, 4, 8}. Again, using PDCH, multimedia data, such as video data, can be segmented into "slices" that fit the available physical layer packet size. In cdma2000, PDCH has different data rates available for forward PDCH (F-PDCH) and reverse PDCH (R-PDCH). In cdma2000, F-PDCH has slightly less available bandwidth than R-PDCH. This difference in bandwidth can be utilized, but in some cases it is advantageous to limit the R-PDCH to the same bandwidth as the F-PDCH. For example, if the first MS transmits the video stream to the second MS, the video stream is transmitted by the first MS on the R-PDCH and received by the second MS on the F-PDCH. Will be. If the first MS uses the full bandwidth of the R-PDCH, then some of the data streams will adapt it to the bandwidth of the F-PDCH transmission to the second MS. Will have to be removed. Bandwidth of the R-PDCH to reduce the difficulty associated with reformatting the transmission from the first MS so that it can be transmitted to the second MS on a channel with a narrower bandwidth. The width can be limited so that it is the same as F-PDCH. One way to limit the F-PDCH bandwidth is to limit the size of application data packets sent over the R-PDCH to those supported by the F-PDCH, and then in the R-PDCH physical layer packet. For the remaining bits "stuffing bit (stuffing) bits) is to be added. In other words, if the stuffing bit is added to the R-PDCH data packet to fit the F-PDCH data packet, then the R-PDCH data packet will be stuffed with minimal changes, eg stuffing. It can be used on F-PDCH forward links by simply removing the bit.
Using the techniques just described, Table 3 adds the possible physical layer data packet sizes for F-PDCH and R-PDCH for four possible data rate cases, and to R-PDCH. List the number of possible "stuffing bits".<tables num="3"><img file="JP4448171B2_D0003.tif" /></tables>
When a multimedia stream such as a video stream is split into slices, such as EBR using DCCH plus SCH, smaller slice sizes generally improve error resilience, but compression efficiency. May hurt. Similarly, if larger slices are used, there will generally be an increase in compression efficiency, but the loss of individual packets will result in more data loss of the lost packets. Therefore, the system performance may decrease.
The above examples have described shared channels such as EBR using dedicated channels, DCCH plus SCH in various radio configurations, and PDCH, but other channels and channel combinations can also be used. For example, EBR could use PDCH plus SCH, or PDCH plus DCCH, or all three could be used together. In addition, any of the other channels available for transmitting data can be used with EBR.
Similarly, techniques for combining multimedia data, such as video slices, to the available size of physical layer packets can be performed in systems based on other radio standards. For example, in a system based on GSM, GPRS, or EDGE, multimedia frames such as video slices can be sized to fit the available time slots. As shown above, many GSM, GPRS and EDGE devices can receive multiple time slots. Therefore, depending on the number of time slots available, the coded stream of the frame can be constrained so that the video slice fits into the physical packet. In other words, the multimedia data can be encoded so that the packet size matches the available size of the physical layer packet, such as a GSM time slot, and the total data of the physical layer packet used. The rate supports the data rate of multimedia data.
FIG. 10 shows the transmission of 10 fps video streams using EBR on a cdma2000 system using DCCH and SCH. In this example, it is assumed that DCCH and SCH are configured in RS1 and 2xinRC3, respectively (Case 1 in Table 2). In this configuration, there are four physical layer packet sizes, 0, 20, 40, and 60 bytes, available in each 20ms time slot. Since the video frame rate is 10 fps, up to 5 time slots can be used to send individual frames of data for a frame period of 100 milliseconds. Thus, each video frame can be divided into up to 5 slices, and each slice can be 0, 20, 40 or 60 bytes.
In the example of Figure 10, there are five MPEG-4 video frames 1002, 1004, 1006, 1008, and 1010. Two of the video frames are I-frames 1002 and 1010, which contain 250 and 200 bytes of data, respectively. The three frames 1004, 1006, and 1008 between the I frames are P frames, which contain 20, 80, and 50 bytes of data, respectively. In Figure 10, a data stream consisting of 20 ms time slots is also shown.
As shown above, in this example up to 5 time slots can be used to carry each video frame. In this example, the frames are segmented into slices to maximize the amount of time the data is not transmitted, maximizing the amount of time the channel is in dtx. Choosing a partition in this way can reduce total interference in the communication system by reducing the amount of time data is being transmitted. In other examples, other considerations may lead to other selection methods. For example, in some situations it may be desirable to maintain a minimum level or continuity of communication between MS and BS. For example, it may be desirable to have a sufficient level of communication so that the BS can keep the MS power controller enabled. Thus, it may be desirable to partition the slices so that a certain amount of data is transmitted within all or the desired number of time slots.
In the example shown in FIG. 10, slices will be sized to use the maximum packet size among the smallest number of time slots to carry data. In this example (Case 1 in Table 2), the maximum packet size is 60 bytes, so the frame will be split into as few 60-byte slices as possible. The first I-frame 1002 is 250 bytes, it will be divided into 5 slices, the first 4 slices will be 60 bytes in size, and the 5th slice will be 10 bytes. There will be. Encoded slices are assigned to time slots 1022, 1024, 1026, 1028, and 1030. The first four time slots 1022, 1024, 1026, and 1028 are configured to use DCCH + SCH to carry 60-byte physical layer packets, and the fifth time slot 1030 is a 10-byte slice. DCCH and SCH to transmit Consists of dtx. Thus, the first 250-byte I-frame is transmitted between the five time slots 1022, 1024, 1026, 1028, and 1030.
It is noted that the 10-byte slice transmitted in time slot 1030 does not completely fill its associated 20-byte physical layer data packet. In such situations, when the physical layer has excess capacity, stuffing bits may be added to "fill" the physical layer data packets. Alternatively, the coding of the slice can be adjusted to take advantage of the excess physical layer capacity. For example, the quantization parameter of the encoded one can be increased for the slice and can improve the quality of the portion of the video transmitted in the slice. It is advantageous to improve the quality of the part of the video, as the subsequent P-frames may not require as much data as the result of improved quality.
The second video frame 1004 is a P frame that is 20 bytes in size. Again, five time slots 1032, 1034, 1036, 1038 and 1040 are available for transmission of this frame. Since this frame is only 20 bytes, it can be fully transmitted during the first time slot 1032 so configured with DCCH and SCH dtx which carry 20 bytes. Since all frames of data can be transmitted in the first time slot 1032, the remaining four time slots 1034, 1036, 1038, and 1040 available in this frame are configured in dtx. ..
The third video frame 1006 is a P frame that is 80 bytes in size. Again, five time slots 1042, 1044, 1046, 1048 and 1050 are available for transmission of this frame. Partitioning this video frame into the first slice of 60 bytes leaves 20 bytes in the second slice. Therefore, the first slice is transmitted in time slot 1042, which is configured to use DCCH + SCH to transmit the 60-byte slice. The second slice is transmitted in the second time slot 1044, which consists of a DCCH carrying 20 bytes and a SCH composed of dtx. The remaining three time slots 1046, 1048, and 1050 are configured in dtx.
The fourth video frame 1008 is a P-frame, which is 50 bytes in size. Again, five time slots 1052, 1054, 1056, 1058 and 1060 are available for transmission of this frame. Since the size of this frame is larger than either a DCCH or SCH physical layer packet, a 60-byte combined DCCH + SCH physical layer packet size will be used. There is insufficient data to fill the DCCH + SCH physical layer packet, so a stuffing bit that adjusts what is encoded to improve quality, or some other technique, produces a physical layer packet. May be used for. Therefore, slices are transmitted in time slot 1052, which is configured to use DCCH + SCH to transmit 60-byte slices. The remaining four time slots 1054, 1056, 1058, and 1060 are configured in dtx.
The fifth and final video frame 1010 in this example is an I-frame, which is 200 bytes in size. Again, five time slots 1062, 1064, 1066, 1068 and 1070 are available for transmission of this frame. The frame is divided into three 60-byte slices and one 20-byte slice. The three 60-byte slices are transmitted in the time slots 1062, 1064, and 1066 configured in DCCH + SCH to carry 60 bytes. The fourth slice, which is 20 bytes, is transmitted in time slot 1068, which consists of DCCH and SCH dtx that carry the 20-byte slice. The last time slot available for this frame is configured in dtx.
In the above example, when the time slot carried a data packet of 20 bytes or less, it was assigned to the DCCH. Data packets could also have been assigned to the SCH instead.
Figure 11 is a bar graph comparing the quality of several sample video sequences transmitted using variable bit rate channels and explicit bit rate channels, as measured by the peak signal-to-noise ratio (PSNR). Is. As shown in Figure 11, the various combinations of channel configurations for DCCH and SCH provide sufficient granularity to deliver almost the same PSNR compared to traditional VBR. Therefore, in these examples, the combination of 10 different date rate combinations on 5 time slots provides pseudo-variable rate channels (pseudo-variable rate channels) that provide performance that is fairly close to that provided by VBR channels with infinite particle size. a pseudo variable rate channel) is effectively generated.
According to the aspect of EBR technology, for each video frame, a spectrum of all possible DCCH and SCH physical layer packet size combinations is generated. The physical layer packet size is then selected to fit the well-thought-out slice size. Any excess data rate capacity in the selected physical layer packet size can be "filled" by stuffing bytes, by quality-adjusting encoder parameters, or by other techniques. When using stuffing bytes, a finer Macroblock Quantizer (larger quantization parameter) results in more slices of smaller size to minimize the amount of stuffing bytes. May be used. FIG. 12 is a bar graph showing a histogram of typical slice distributions for DCCH and V-SCH.
Appropriate control mechanisms may be used to match the multimedia encoder slice size to the available physical layer packet or payload size, as shown in Figures 11 and 12 and Tables 2 and 3. it can. As a result of this "matching", multimedia data such as video data can be transmitted over variable bitrate channels without compromising compression efficiency compared to true constant bitrate channels. , And the error recovery power can be improved.
FIG. 13 is a bar graph comparing quality simulations of various video sequences transmitted over the VBR and EBR-PDCH channels, as measured by the peak signal-to-noise ratio (PSNR). As shown in FIG. 13, there is a very small reduction in PSNR for EBR-PDCH transmission compared to VBR transmission.
FIG. 14 is a bar graph showing the distribution of slice sizes of the multimedia encoder. In this example, the multimedia encoder is constrained to a slice size of 90 bytes, except for the last slice of each multimedia frame that has the option of being either 90 bytes or 45 bytes in size. As shown in FIG. 14, in this example, over 90% of the slices are 90 bytes in size and are efficient without degradation due to packet loss due to the larger packet size. It leads to the use of various channels.
The quality comparison bar graphs in Figures 13 and 14 show that in the case of EBR-PDCH, the use of a multimedia encoder or codec slice size to match the available physical layer packet size results in comparison with VBR. This shows that it provides high quality transmission of multimedia data without compromising compression efficiency.
The above example shows that multimedia encoders such as the AVC / H.264 video codec can achieve similar compression efficiencies in EBR and VBR modes. As shown by the example above, EBR achieves VBR-like performance on both dedicated channels such as DCCH plus V-SCH and shared channels such as PDCH. Other multimedia encoders, such as video codecs (eg MPEG-4 and H.263 +), have motion estimation and DCT transformation on the displaced block for replaced block differences. Since differences) is used, it is expected that similar EBR operation will be possible for other video codecs and other radio channels. In addition, it should be noted that the rate control mechanism remains for implementation in the ITU and ISO / IEC video codec specifications. Therefore, EBR conforms to existing standards, and a compliant decoder will be able to decode video streams encoded with EBR rate control.
The above example is described for CDMA based systems such as cdma2000, but the same technology is applicable to other air interfaces. For example, a system based on GSM, GPRS, or EDGE may use the same techniques as described above. As shown in FIG. 3, these systems carry data within multiple time slots of a wireless frame. Choosing a multimedia slice size based on the number of time slots would be similar to choosing a slice size based on the channels available in a CDMA based system. Similarly, just as slicing to fit a CDMA physical packet, slicing to fit a time slot improves error resilience.
As shown in these examples, one aspect of the EBR is a slice of a multimedia data frame, as defined for, for example, cdma2000 (V-SCH + DCCH, SCH + DCCH, PDCH) and WCDMA (DCH). Is to fit the available set of physical layer packet sizes. In one embodiment, the recipient node, such as the MS, negotiates the communication channel configuration and thus the physical layer packet size with the PDSN in the infrastructure. For streaming and broadcast applications, in addition to the negotiation between the MS and PDSN, there may be a negotiation between the MS and the content server. Therefore, there is end-to-end coordination between the end-point applications and the underlying network.
According to one embodiment, the first channel comprises variable rate, and therefore variable physical layer packet size, channel, which may consist of multiple logical channels, including several variable bit rate and constant bit rate channels. ing. The video encoder may include a rate control buffer that supports shaping of video traffic that allows the transmission of video information with zero buffer-delay. The constant bit rate channel may include, for example, a Dedicated Control Channel (DCCH) through which a P-type video frame is transmitted. For example, a second radio channel may also be provided, including a Variable-rate Supplemental Channel (V-SCH) shared among multiple recipient nodes. The second radio channel may have a higher rate than the rate of the first radio channel. In some embodiments, the type I video frame is transmitted over a variable rate supplemental channel (V-SCH).
According to one aspect of the invention, each video frame is sent on multiple physical layer frames. For example, a dedicated control channel (DCCH) has a first rate, and a variable rate supplemental channel (V-SCH) has multiple rates, such as 1st rate, 2nd rate, 3rd rate, 4th rate and 5th rate. Have a rate. In addition, both channels have a DTX rate at which nothing is transmitted. During each physical layer frame, multiple transmission formats are defined for each combination of rates on the dedicated control channel (DCCH) and the variable rate supplemental channel (V-SCH). The number of configurations is at least the product of the number of transmission formats and the number of physical layer frames. The video frame slice size may correspond to one of the configuration based on the video frame size. The encoder may include a rate control module, which controls the desired slice size and configuration to fit the available size of physical layer packets based on the size of the video frame. As such, video latency Latency) can be reduced for both dedicated and shared channels by matching the code rate to one of the available channel rates.
In one technique, the size of the delivered data is estimated by the MS, and this process is called "Blind Detection". In another technique called "Explicit Indication", the size of the delivered data can be indicated by using additional signaling, which requires blind detection. It can be eliminated. For example, in the case of WCDMA, the size of the delivered data packet is "Transport format combination". Since it can be indicated using an "indicator" (TFCI), the MS does not need to do blind detection and therefore bears the computational burden on the MS when variable size packets are used as in EBR. Reduce. The described EBR concept is applicable to both blind detection and explicit display of packet size. Therefore, it is clear that the physical layer packet size arriving at the MS may vary over time, but as with TFCI in WCDMA, the MS may either by blind detection or explicit signaling of the packet size. The size of the packet can be identified by either through.
On the other side, the SCH allocation is at a very low rate (eg 32kbps). This is done so that far more users can be supported in the network without emptying the Walsh space. In this case, the video quality is improved by allowing n video frames to occupy a time slot in n * T seconds, where T = 1 / frames_pers_second.
In another embodiment, instead of limiting each video frame to T seconds, n video frames share n * T seconds. For example, if the video stream has a 10fps rate, then instead of transmitting frames every 100ms, it is possible to transmit two frames every 200ms. FIG. 15 is a diagram showing an example of transmitting two 10 fps video frames over a period of 200 milliseconds. In the example of Figure 15, it is assumed that DCCH and SCH are configured in RS1 and 2x in RC3, respectively (Case 1 in Table 2). In this configuration, there are four physical layer packet sizes, 0, 20, 40, and 60 bytes, available every 20 ms time slot. In this example, two 10fps video frames are transmitted every 200 milliseconds. In this way, the two video frames share a 10 time slot in which the data in both frames is transmitted. Thus, each video frame can be divided into slices that can be either 0, 20, 40 or 60, resulting in the total number of slices combined for the two frames (the combined total number of slices) is 10 (ten of fewer slices) of fewer slices.
In the example of Figure 15, there are two MPEG-4 video frames 1502 and 1004. The first video frame 1502 is an I frame that is 540 bytes in size, and the second video frame 1504 is a P frame that is 60 bytes in size. In this example, the I-frame 1502 can be divided into nine slices, each 60 bytes in size, and the P-frame 1504 can be divided into one slice, which is 60 bytes in size. The I-frame 1502 slice is configured to use DCCH + SCH to carry 60-byte physical layer packets. Nine time slots 1510, 1512, 1514, 1516, 1518, 1520, 1522, 1524, and 1526. Can be transmitted during the period of. P-frame 1504 slices can be transmitted during a single time slot 1518 period that is configured to use DCCH + SCH to carry 60-byte physical layer packets. Thus, two 10fps video frames are transmitted over a 200ms period, resulting in an average rate of 10fps.
Instead of limiting each video frame to T seconds, as shown in Figure 15, n video frames share n * T seconds. In this way, a trade-off is achieved between the frequency domain limit (peak rate, Walshspace) and the time domain limit (delay). In this example, I-frame 1502 is assigned nine time slots, and P-frame 1504 is assigned one time slot. It is envisioned that any other allocation of time slots between frames can also be used. For example, eight, seven, or six time slots can be assigned to one frame, and two, three, or four time slots can be assigned to different frames, respectively. This example also showed a shared time slot between two frames, but it is also expected that the time slot can be shared between any number of frames.
According to another embodiment, the first channel comprises a variable bit rate channel that supports multiple rates, such as a shared Packet Data Channel (PDCH) with variable delay. The variable bit rate channel rate matches the encoding rate of the video information packet from the video encoder. The controller may also include an arbitrate scheduler to ensure that the controller transmits video information over the first radio with a fixed delay. Good. According to another aspect of the invention, the receiver node limits the R-PDCH rate to match the F-PDCH rate by imposing a stuffing bit. According to another aspect of the invention, the scheduler in the controller uses a delay for the SMG in the PDCH.
In another embodiment, a third radio channel can also be provided. The transmitting node can further include an audio encoder that produces frames of audio / speech information. The serving node receives a frame of audio / speech information from the transmitting node and supplies a packet of audio / speech information to the controller. The controller transmits a packet of audio / speech information over the third radio channel to at least one of the recipient nodes. For reverse link or uplink transmission, each recipient node can transmit a packet of audio / speech information to the controller over the third radio channel.
FIG. 16 is a flow diagram showing a method of transmitting multimedia data on a wireless communication channel. The flow begins at block 1602, where the available communication channels that can be used to transmit information are determined. For example, the available communication channels, and their configurations, can be negotiated between the content server or PSDN and the recipient of the content. The flow proceeds to block 1604, where the possible data packet size of the available communication channels is determined, as well as the packet size of the combination of communication channels. After that, the information unit is divided into slices. The number of slices can be determined by the number of time slots available for transmission during the information unit interval, and the slice size does not exceed one of the data packet sizes it can use. Is selected. For example, the number of slices can depend on the number of transmissions that occur during the information unit interval. The flow proceeds to block 1608, and slices are assigned to physical layer packets.
FIG. 17 is a block diagram of a wireless communication device or mobile station (MS) configured according to an exemplary embodiment of the present invention. The communication device 1702 includes a network interface 1706, a codec 1708, a host processor 1710, a memory device 1712, a program product 1714, and a user interface 1716.
Signals from the infrastructure are received by network interface 1706 and sent to the host processor 1710. The host processor 1710 receives the signal and responds with the appropriate action, depending on the content of the signal. For example, the host processor 1710 may decode the received signal itself, or it may send the received signal to codec 1708 for decoding. In another embodiment, the received signal is sent directly from network interface 1706 to codec 1708.
In one embodiment, network interface 1706 may be a transceiver and antenna that interfaces to the infrastructure over a radio channel. In another embodiment, the network interface 1706 may be a network interface card used to interface the infrastructure over a terrestrial line. Codec 1708 may be implemented as a digital signal processor (DSP), or a general purpose processor such as a central processing unit (CPU).
Both the host processor 1710 and the codec 1708 are connected to the memory device 1712. The memory device 1712 can be used to store data during the operation of the WCD, as well as to store the program code executed by the host processor 2210 or DSP2208. For example, the host processor, codec, or both may operate under the control of programming instructions that are temporarily stored in memory device 1712. Host processors 1710 and codec 1708 can also include their own program storage memory. When programming instructions are performed, the host processor 1710 and / or codec 1708 perform their functions, such as decoding or encoding multimedia streams. Thus, the programming step implements the functionality of the respective host processor 1710 and codec 1708, so that the host processor and codec each perform the function of decoding or encoding the desired content stream. Can be made like this. Programming steps can be received from program product 1714. Program product 1714 may store programming steps and transfer them to memory 1712 for execution by the host processor, codec, or both.
Program product 1714 may be a semiconductor memory chip such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, in addition to storage devices such as hard disk, removable disk, CD-ROM. Alternatively, it may be any form of storage medium known in the art capable of storing computer-readable instructions. In addition, program product 1714 may be a source file containing program steps that are received from the network, stored in memory, and then executed. As described above, the processing steps required for the operation according to the present invention can be embodied on the program product 1714. In FIG. 17, an exemplary storage medium is shown coupled to the host processor 1710 so that the host processor can read information from and write information to the storage medium. Alternatively, the storage medium may be integrated with the host processor 1710.
User interface 1716 is connected to both host processor 1710 and codec 1708. For example, user interface 1716 can include displays and speakers used to output multimedia data to the user.
Those skilled in the art will recognize that the steps of the method described in connection with embodiments can be interchanged without departing from the scope of the invention.
Those skilled in the art will also appreciate that information and signals can be represented using any of a variety of different techniques and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be voltage, current, electromagnetic waves, magnetic fields or or magnetic particles, light fields or optical particles, or theirs. It can be represented by any combination.
Those skilled in the art will further appreciate the various explanatory logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein as electronic hardware, computer software, or a combination of both. You will recognize that it can be implemented. To articulate this compatibility of hardware and software, various descriptive components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether their functionality is implemented as hardware or software depends on the specific application and design constraints imposed on the entire system. Skilled and skilled craftsmen may implement functionality described in different ways for each particular application, but decisions on such implementation deviate from the scope of the invention. Should not be interpreted.
The various explanatory logic blocks, modules, and circuits described in connection with the embodiments disclosed herein include general purpose processors, digital signal processors (DSPs), application specific ICs (ASICs), and field programmable gates. It can be implemented or performed using an array (FPGA) or other programmable logic device, discrete gate or transistor logic, a discrete hardware component, or any combination of these designed to perform the functions described herein. .. The general purpose processor may be a microprocessor, but otherwise the processor may be any conventional processor, controller, microcontroller, or state machine. Processors are also implemented as a combination of arithmetic units, such as a combination of DSP and microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration. May be done.
The methods or techniques described in connection with the embodiments disclosed herein can be embodied directly in hardware, in software modules executed by a processor, or in combination of the two. Software modules are present in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of technically known storage medium. sell. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write the information to the storage medium. Alternatively, the storage medium may be built into the processor. The processor and storage medium may reside in the ASIC. The ASIC may exist in the user terminal. Alternatively, the processor and storage medium may be present as discrete components within the user terminal.
The above description of the disclosed embodiments is provided to allow anyone of ordinary skill in the art to make or use the present invention. Various variations of these embodiments will be readily apparent to those of skill in the art, and the comprehensive principles defined herein apply to other embodiments without departing from the spirit or scope of the invention. Can be done. Therefore, the present invention is not intended to be limited to the embodiments presented herein, but should be provided with the broadest scope consistent with the principles and novel features disclosed herein.
<figref num="1">FIG. 1 is an explanatory diagram of a part of a communication system 100 configured according to the present invention.</figref><figref num="2">FIG. 2 is a block diagram showing an exemplary packet data network and various air interface options for delivering packet data over the wireless network in the system.</figref><figref num="3">FIG. 3 is a block diagram showing two radio frames 302 and 304 in the FIG. 1 system utilizing the GSM air interface.</figref><figref num="4">FIG. 4 is a diagram showing a protocol stack for packet data in a wireless communication system.</figref><figref num="5">FIG. 5 shows a coded video stream of a video frame that identifies different parts of the stream using typical syntax.</figref><figref num="6">Figure 6 shows a histogram of slice sizes for AVC / H.264 encoded video sequences when the maximum size is constrained or limited to 189 bytes.</figref><figref num="7">FIG. 7 shows the various levels of encapsulation that exist when transmitting multimedia data such as video data over wireless links that use the RTP / UDP / IP protocol.</figref><figref num="8">FIG. 8 is a diagram showing an example of allocating an application data packet such as a multimedia data packet to a physical layer data packet.</figref><figref num="9">FIG. 9 is a diagram showing the time slot characteristics of a system based on cdma2000 when multiple CBR channels are used to generate pseudo-VBR channels.</figref><figref num="10">FIG. 10 shows the transmission of a 10 fps video stream using EBR on a cdma2000 system using DCCH and SCH.</figref><figref num="11">Figure 11 is a bar graph comparing the quality of several sample video sequences transmitted using variable bit rate channels and explicit bit rate channels, as measured by the peak signal-to-noise ratio (PSNR). Is.</figref><figref num="12">FIG. 12 is a bar graph showing a histogram of typical slice distributions for DCCH and V-SCH for a typical video clip.</figref><figref num="13">FIG. 13 is a bar graph comparing quality simulations of various video sequences transmitted over the VBR and EBR-PDCH channels, as measured by the peak signal-to-noise ratio (PSNR).</figref><figref num="14">FIG. 14 is a bar graph showing the distribution of slice sizes for multimedia encoders constrained for PDCH channels.</figref><figref num="15">FIG. 15 shows an example of transmitting two 10 fps video frames over a 200 ms period in an I frame that utilizes more time slots than adjacent P frames.</figref><figref num="16">FIG. 16 is a flow diagram showing a method of transmitting information data on a wireless communication channel.</figref><figref num="17">FIG. 17 is a block diagram of a wireless communication device or mobile station (MS) configured according to an exemplary embodiment of the present invention.</figref>
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| TW200623737A | Taiwan Province of China | A | |
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| KR20070014201A | Republic of Korea | A | |
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| EP1757027B1 | European Patent Office (EPO) | B1 | |
| ATE417436T1 | Austria | T1 | |
| DE602005011611D1 | Germany | D1 | |
| EP1751955B1 | European Patent Office (EPO) | B1 | |
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| ES2318495T3 | Spain | T3 | |
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| Cancellation because of no payment of annual feesLAPS | LAPS | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
| Receipt of annual feesJAPANESE INTERMEDIATE CODE: R250R250 | R250 | |
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Numbers
- Publication
- 4448171
- Publication, DOCDB
- 4448171
- Publication, EPODOC
- JP4448171B
- Application
- 2007513421
- Application, DOCDB
- 2007513421
- Application, EPODOC
- JP20070513421
Titles2
- Japanese
- 通信システムのチャンネルへの情報の割り当てのための方法および装置
- English
- Methods and equipment for assigning information to channels of communication systems
Classification
- CPC, 36
- H04L69/04
- H04W28/06
- H04N21/2381
- H04N21/41407
- H04N21/44004
- H04N21/4788
- H04N21/6131
- H04N21/6181
- H04N21/6437
- H04N21/64707
- H04W28/065
- H04W72/1263
- H04W80/00
- H04W84/04
- H04W88/181
- H04L65/80
- H04L69/166
- H04L69/22
- H04L69/161
- H04N19/102
- H04N19/115
- H04N19/61
- H04N19/124
- H04N19/152
- H04N19/164
- H04N19/174
- H04L69/321
- H04L47/36
- H04W4/06
- H04L65/764
- H04L65/00
- H04L9/40
- H04L65/75
- H04L65/1101
- H04W72/044
- H04W88/02
- IPC, 12
- H04W84 12
- H04B7 00
- H04B7 216
- H04L12 28
- H04L12 56
- H04L12 66
- H04L47 36
- H04N7 26
- H04W28 06
- H04W72 12
- H04W84 04
- H04W88 18