WO2007025454A1 - Methode et systeme de retransmission de donnees avec abaissement de couche dans une communication sans fil - Google Patents

Methode et systeme de retransmission de donnees avec abaissement de couche dans une communication sans fil Download PDF

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Publication number
WO2007025454A1
WO2007025454A1 PCT/CN2006/002040 CN2006002040W WO2007025454A1 WO 2007025454 A1 WO2007025454 A1 WO 2007025454A1 CN 2006002040 W CN2006002040 W CN 2006002040W WO 2007025454 A1 WO2007025454 A1 WO 2007025454A1
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Prior art keywords
layer
mac
rlc
retransmission
base station
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PCT/CN2006/002040
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English (en)
French (fr)
Inventor
Yali Qin
Rongqiang Li
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Huawei Technologies Co., Ltd.
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Publication of WO2007025454A1 publication Critical patent/WO2007025454A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H04L1/1874—Buffer management

Definitions

  • the present invention relates to the field of wireless communication technologies, and in particular, to a wireless communication downlink data retransmission method and system. Background technique
  • WCDMA Wideband Code Division Multiple Access
  • ITU International Telecommunications Union
  • FDD Frequency Division Duplex
  • WCDMA is a CDMA system using Direct Sequence Spread Spectrum (DSSS) technology, which spreads the user bandwidth to more than 1000 times by spreading codes and expands the channel bandwidth to 5 MHz. This allows reliable transmission of information at the same transmission rate with very low signal-to-noise ratio. It greatly enhances anti-jamming capability and implements code division multiple access, which can support various user data rates.
  • DSSS Direct Sequence Spread Spectrum
  • the earliest version of WCDMA protocol is R99.
  • the bearers of uplink and downlink services are based on dedicated channels, and the data transmission rate that can be achieved is 384Kbps.
  • the WCDMA standard-setting organization subsequently introduced the network protocols of three phases: R4, R5, and R6, and introduced high-speed downlink packet access (HSDPA, High Speed Downlink Packet Access).
  • HSDPA High Speed Downlink Packet Access
  • Technology and High Speed Uplink Packet Access (HSUPA) technology can provide peak rates of up to 14.4Mbps and 5.76Mbps, respectively, while greatly improving spectrum efficiency.
  • HSDPA High-order modulation is introduced to improve the spectrum utilization, and the shared channel scheduling of each user equipment (UE, User Equipment) is implemented by code division and time division.
  • the HARQ technology requires the base station node (NodeB) to send the data to the UE, and needs to obtain the response data of the UE feedback acknowledgement ACK (acknowledgement) / NACK (no acknowledgement) to determine whether the UE has correctly received the data, so as to determine the number of retransmissions. According to the new data.
  • NodeB base station node
  • ACK acknowledgement
  • NACK no acknowledgement
  • HSDPA adds two physical channels in the downlink, one is the High Speed Physical Downlink Shared Channel (HS-PDSCH), which is used to carry the user's data information, and the other is the high-speed shared control channel (HS-SCCH). , High Speed Shared Control Channel), used to carry the signaling required to demodulate the accompanying data channel HS-PDSCH.
  • HSDPA adds a High Speed-Dedicated Physical Control Channel (HS-DPCCH) to the uplink, which is used to carry the feedback downlink data frame through the high-speed physical downlink shared channel (HS-PDSCH, High Speed Physical).
  • HS-DPCCH High Speed-Dedicated Physical Control Channel
  • the Medium Access Control (high-speed access control) (MAC-hs, Medium Access Control-high speed) sub-layer is added to support the flow control of HSDPA, fast scheduling/priority management, HARQ.
  • MAC-hs Medium Access Control-high speed sub-layer
  • TFRI Transport Format and Resource Indicator
  • the MAC-hs is located under the MAC-d (d refers to dedicated) of the MAC layer, above the physical layer.
  • HSUPA in the R6 version, requires two new uplink physical channels for the user, one is the enhanced dedicated physical data channel (E - DPDCH, Enhanced - Dedicated Physical Data Channel) for transmitting data, and the other is transmission accompanying Enhanced Layer-Dedicated Physical Control Channel (E-DPCCH), which provides accompanying signaling for the former demodulation.
  • E- DPDCH enhanced dedicated physical data channel
  • E-DPCCH Enhanced Layer-Dedicated Physical Control Channel
  • the absolute channel E-AGCH, Enhance - Absolute Granted Channel
  • E-RGCH Enhanced Grant Channel
  • the cell exists to indicate that the user can transmit the maximum transmission rate in the uplink, and the adjusted frequency is relatively low.
  • the relative authorization channel may exist in both the serving wireless connection and the non-serving wireless connection cell, and is used to indicate that the user adjusts the uplink according to a certain step. Transmission rate, the frequency of adjustment is relatively high, up to every 2ms-times.
  • a channel indicating whether the uplink process data transmission is correct is also added in the downlink channel, and is used to tell the user whether the data sent is correct.
  • MAC-e refers to enhancement
  • MAC-es are introduced in the MAC layer to support HARQ and fast scheduling.
  • the MAC-e protocol data unit can be utilized. (MAC-e Protocol Data Unit) carries the signaling and reads this signaling at the MAC-e layer of the base station.
  • signaling MAC-es PDUs may be multiplexed, that is, multiple MAC-es PDUs are integrated into MAC-e PDUs.
  • MAC-e and MAC-es are between the physical layer and MAC-d.
  • E-DCH enhanced dedicated channel
  • UTRAN Universal Terrestrial Radio Access
  • data from the physical layer is sorted according to the number of retransmissions and decomposed into different MAC-d flows.
  • the structure of the WCDMA protocol is shown in Figure 1. Above the physical layer, it is the Medium Access Control (MAC) layer, the Radio Link Control (RLC) layer, and other high layers.
  • MAC Medium Access Control
  • RLC Radio Link Control
  • AM Acknowledged Mode
  • the HARQ transmission error of the physical layer is prevented, and the RLC layer of the receiving end is received.
  • the RLC layer retransmission is requested according to the sequence number status of the received RLC Protocol Data Unit (PDU), and the RLC layer receiving the request at the transmitting end initiates the RLC layer retransmission. That is to say, when the physical layer retransmission fails, the system needs to start the RLC layer, and even the higher layer retransmission.
  • PDU RLC Protocol Data Unit
  • the physical layer and part of the MAC layer are located in the base station, and the RLC layer and above are located in the Radio Network Controller (RNC), and there is a standard interface between the base station and the radio network controller.
  • RLC Radio Network Controller
  • the RLC layer In the AM mode, if the physical layer cannot correct the transmission error of the data by retransmission, the RLC layer needs to initiate retransmission to ensure the correct transmission of the service data.
  • the RLC layer retransmission process of the downlink transmission is: 1) At the UTRAN end, the RLC layer transmits the RLC service data unit from the upper layer. (SDU, Service Data Unit) Segmentation or merging generates equal-sized RLC AMD PDUs (acknowledgement mode RLC PDUs). The size of the RLC AMD PDU is determined by the parameter AMD RLC size (the RLC size in the acknowledge mode). The resulting AMD PDU is placed in the retransmitted buffer for transmission.
  • SDU Service Data Unit
  • the MAC layer will receive the MAC PDU and remove the data header of the MAC layer to obtain the PDU of the RLC layer and transmit it to the RLC layer.
  • the sequence number of the AMD PDU is used to confirm whether the LC AMD PDU is correctly received. If received correctly, an acknowledgment message is sent to the peer UTRAN RLC layer. If retransmission is not received correctly, the message requesting retransmission is sent to the peer UTRAN RLC layer.
  • the RLC layer performs different operations according to the received UE acknowledgement information or retransmission request. If an acknowledgment is received, the RLC AMD PDU is no longer sent and the data cache of the RLC AMD PDU is flushed. If the retransmission request is received, and the number of retransmissions of the RLC layer is not exceeded, the retransmitted RLC AMD PDU is placed in the retransmission buffer for transmission, and the data block is retransmitted to the base station, and the physical channel of the base station Beared to the UE.
  • the transmitting end can parse the receiving feedback information of the receiving end at the RLC layer.
  • the downlink RLC layer retransmission is performed, and the UE first stores the received RLC AMD PDU in the received RLC cache area until all RLC AMD PDUs corresponding to a complete RLG SDU are received.
  • the RLC layer determines whether all RLC AMD PDUs corresponding to the RLC SDU are correctly received by the sequence number of the RLC AMD PDU. If the RLC AMD PDU is lost, the retransmission indication sent by the UE sender requests retransmission.
  • the content of the retransmission indication sent by the UE is analyzed, and it is determined whether the RLC AMD PDU needs to be retransmitted.
  • This process requires the Iub/Iur interface to pass information, so it takes a long time. Since the RLC is in the RNC, the retransmission of the RLC involves R C processing, base station processing, and data transmission between the two. Excessive intermediate processing also results in extended transmission time.
  • the RLC layer of the UTRAN does not receive the number fed back by the UE peer-to-peer RLC layer According to the status report that has been correctly received, it is necessary to retain the data at the RLC layer. For the high-speed data service flow, it is easy to cause the RNC's cache resources to be tight and affect its processing capability.
  • the main object of the present invention is to provide a downlink data retransmission method in a wireless communication system, so that the retransmission time is greatly reduced, the buffer amount of the data packet on the RNC side is greatly reduced, and the processing capability of the RNC is improved.
  • a method for retransmitting a wireless communication downlink data includes the following steps: the base station sends the downlink data packet to the user equipment after being buffered in the specified layer;
  • the UE generates a retransmission indication according to the check result of the correctness of the received data packet at the radio link control RLC layer, and the UE multiplexes the retransmission indication to the protocol data unit of the designated layer at the designated layer, and Sending to the base station;
  • the base station After receiving the protocol data unit, the base station decrypts the retransmission indication, and the specified layer refreshes the specified layer cache according to the retransmission indication and the data packet that is not correctly transmitted in the cache Resending to the client;
  • the base station and the user end both include the designated layer, and the user end has a function of multiplexing upper layer signaling to the designated layer uplink protocol data unit at a specified layer, and the base station has a corresponding demultiplexing function at a specified layer. .
  • the designated layer is a MAC layer
  • the RLC layer sends data to the specified layer and checks the correctness of the received packets.
  • the MAC-e sublayer in the MAC layer implements a function of multiplexing and demultiplexing retransmission indication.
  • the downlink data packet is an RLC acknowledgment mode protocol data unit, and the MAC encapsulates the RLC acknowledgment mode protocol data unit into a MAC-d protocol data unit, where the RLC acknowledges the mode protocol data unit and the MAC-d protocol data unit— - correspondence;
  • the retransmission indication may include one of the following information or any combination thereof:
  • Confirmation information movement of the downlink RLC acknowledgment mode protocol data unit that has been correctly received
  • the receive window acknowledgement information the list information of the RLC acknowledge mode protocol data unit that was not correctly received
  • the relative list information of the RLC acknowledge mode protocol data unit that was not correctly received The receive window acknowledgement information, the list information of the RLC acknowledge mode protocol data unit that was not correctly received, and the relative list information of the RLC acknowledge mode protocol data unit that was not correctly received.
  • the MAC-e protocol data unit is carried on an uplink dedicated enhanced data channel for high speed uplink packet access.
  • the data packet in the MAC layer cache is confirmed to be correctly received or the number of failed retransmissions reaches a preset threshold, and is to be transmitted.
  • the data packet is a data packet carrying a real-time service.
  • the retransmission data is high speed downlink packet access data.
  • the wireless communication system is one of a wideband code division multiple access system, an orthogonal frequency division multiplexing system, a multiple input multiple output system, and an evolved system thereof.
  • a wireless communication downlink data retransmission system having a base station and a user terminal, including:
  • a storage unit that caches downlink data packets in the base station at the designated layer
  • an update and retransmission unit configured in the base station, refreshing, in the specified layer, the data packet in the storage unit according to the retransmission indication, and resending the data packet that is not correctly transmitted to the user terminal;
  • the user terminal retransmits the multiplex protocol data unit at the designated layer; the user terminal generates a retransmission indication according to the check result of the correctness of the received data packet at the radio link control RLC layer, and sends the retransmission indication to the base station;
  • the base station and the user terminal both include the designated layer, and the user terminal has the upper layer signaling multiplexed to the designated layer uplink protocol data unit at the designated layer, and the base station performs corresponding demultiplexing at the designated layer.
  • the designated layer is a medium access control MAC layer.
  • the downlink data packet is a radio link control RLC acknowledge mode protocol data unit
  • the MAC buffers the RLC acknowledge mode protocol data unit into a MAC_d protocol data unit, wherein the RLC acknowledge mode protocol data unit corresponds to the MAC-d protocol data unit.
  • the retransmission indication includes one of the following information or any combination thereof:
  • Confirmation information movement of the downlink RLC acknowledgment mode protocol data unit that has been correctly received
  • the receive window acknowledgement information the list information of the RLC acknowledge mode protocol data unit that was not correctly received
  • the relative list information of the RLC acknowledge mode protocol data unit that was not correctly received The receive window acknowledgement information, the list information of the RLC acknowledge mode protocol data unit that was not correctly received, and the relative list information of the RLC acknowledge mode protocol data unit that was not correctly received.
  • the retransmission function of the RLC layer originally implemented in the RNC is moved down to the MAC layer in the base station, and the user equipment is carried by the MAC-e PDU of the HSUPA. Feedback retransmission indication.
  • the base station sends the downlink data packet from the RLC layer to the user equipment after being buffered by the MAC layer, and the MAC-e sublayer of the user equipment multiplexes the retransmission indication in the MAC-e PDU to the base station, and the MAC-e sublayer of the base station
  • the retransmission indication is resolved from the MAC-e PDU and the MAC layer buffer is refreshed accordingly and the erroneous data packet is retransmitted.
  • the retransmission speed is greatly accelerated, and the efficiency is obviously improved.
  • the path involved in the entire retransmission process is shortened.
  • both ends of the retransmission path are the RNC and the UE, and the intermediate station is transited through the base station.
  • the two ends of the path are the base station and the UE.
  • the retransmission time is greatly saved, the delay of the downlink transmission is greatly reduced, the QoS guarantee for the service quality of the delay sensitive service is facilitated, the user satisfaction is improved, and the problems of sound lag and image discontinuity can be reduced or eliminated.
  • the RLC layer buffer on the RNC side can be cancelled.
  • the RLC layer retransmission mechanism in the prior art leads to a relatively large RLC layer buffer of the RNC, which may cause the RNC cache resource to be tight for carrying a high-speed data service flow. Because if the RLC layer of the RNC does not receive the status report that the peer UE's RLC layer feedback data has been correctly received, the data will be retained. Under the high speed data service, the RC cache resource is tight and the processing capability is limited. . If the retransmission function of the RLC layer is implemented in the base station, the AMD PDU data buffer of the RLC layer can be released and replaced by the cache in the base station.
  • the base station can quickly obtain the information that the AMD PDU is correctly received, so that the correct data block buffer can be quickly released, so that the amount of data corresponding to the AMD PDU that the base station actually needs to be cached is greatly reduced, so that the overall processing capability of the UTRAN can be improved. cut costs.
  • the technical solution of the present invention simplifies the protocol architecture. Because the "RLC layer retransmission" function is implemented in the base station, the UTRAN side only needs to perform retransmission of the physical layer, so the protocol architecture can be compressed. At the same time, the base station implements the "RLC layer retransmission" function, which reduces the data retransmission between the base station and the RNC. Bandwidth consumption is brought about, and the effective utilization of the Iub interface is improved.
  • the technical solution of the present invention can carry real-time services. Since the transmission delay is greatly reduced after using the scheme of the present invention, the existing unacknowledged mode bearer service can be changed to be carried by the acknowledge mode, such as real-time service. By confirming the mode bearer, the transmission reliability of these services can be greatly improved.
  • FIG. 2 is a structural diagram of an RLC AMD PDU
  • FIG. 3 is a schematic diagram of a process of multiplexing a retransmission indication to a MAC-e PDU and a MAC-e PDU by a UE side in a preferred embodiment of the present invention
  • FIG. 4 is a schematic diagram of an ACK SUFI structure in a retransmission indication in a preferred embodiment of the present invention
  • FIG. 5 is a schematic diagram of a process of deactivating a MAC-e PDU transmitted by a UE in a preferred embodiment of the present invention
  • FIG. 6 is a flow chart of a method for HARQ retransmission in accordance with a preferred embodiment of the present invention
  • FIG. 7 is a block diagram showing the structure of a downlink data retransmission system in accordance with a preferred embodiment of the present invention. detailed description
  • the core of the present invention is that the retransmission of the RLC layer is moved down to the base station, so that the data retransmission time is close to the data transmission delay of the air interface, thereby greatly reducing the retransmission time and achieving the requirement of carrying real-time services.
  • the retransmission of the RLC layer is reduced, so that the data packets buffered on the RNC side are greatly reduced, the RNC cache resources are saved, and the processing capability of the RNC is improved.
  • a MAC buffer for storing a MAC-d PDU is set up in the base station, and retransmission data in the RLC layer is stored in a MAC buffer in the base station.
  • the data in the MAC buffer is then transmitted to the UE through the physical layer and the air interface.
  • the UE processes the received data through the physical layer and the MAC layer, and then transmits the data to the RLC layer.
  • the LC layer determines whether the data sent from the base station is correctly received, and generates a retransmission indication, which is transmitted to the MAC-e layer of the UE.
  • the MAC-e layer of the UE multiplexes the data and retransmission indication from the RLC layer into MAC-e PDUs, through the physical layer. And the air interface is sent to the base station.
  • the base station transmits the received data to the MAC-e layer of the base station after being processed by the physical layer, and then demultiplexes the data by the MAC-e layer to obtain a retransmission indication of the UE, and determines which are retransmitted by the content of the retransmission indication.
  • the data has been received correctly by the UE and which data needs to be retransmitted.
  • the data that has been correctly received in the cache is updated to new data.
  • the base station initiates an air interface fast retransmission of the data through the downlink HSDPA, and simultaneously retains the data in the buffer until the UE has received the correct reception.
  • the data packet is updated to a new data packet to be transmitted.
  • An embodiment of the present invention is a data retransmission applied to HSDPA in a WCDMA system, see Figure 6.
  • the UTRAN side sets up a MAC buffer for storing the MAC-d PDU in the base station, and stores the retransmission data in the RLC layer into the MAC cache in the base station. Since the data packet stored in the RLC is an RLC AMD PDU, the MAC address in the base station must first encapsulate the RLC AMD PDU into a MAC-d PDU and buffer it. In this embodiment, the RLC AMD PDU and the MAC-d PDU are - Corresponding relationship. A person skilled in the art can understand that the PDU of the RLC layer and the buffered PDU can also be in a one-to-many or many-to-one relationship, and the processing method does not deviate from the spirit of the present invention.
  • the uplink data is transmitted to the RNC side to obtain the RLC layer and higher layer processing, and the information interaction between the RNC and the base station needs to pass through the Iub/ The Iur interface, therefore, if the retransmitted data does not need to be transmitted to the base station through the RC having the RLC layer, and then sent by the base station to the UE through the physical layer and the air interface, but directly transmitted by the base station to the UE, the transmission delay can be reduced.
  • Step 620 After the UTRAN side buffers the retransmission data in the RLC layer to the MAC layer in the base station, the base station transmits the retransmission data to the physical layer, and the physical layer sends the data to the UE through the air interface.
  • Step 630 The RLC layer of the UE checks the correctness of the data packet and generates a retransmission indication. After receiving the data packet sent by the base station on the UTRAN side, the UE is at the RLC layer for the data packet. Check for correctness. Since the data packet received at the RLC layer is an RLC AMD PDU, the structure of the RLC AMD PDU is as shown in FIG. 2, and the transport sequence number carried therein indicates the order of data packet transmission. Therefore, in the RLC, the correctness of the data packet transmission can be checked according to the transmission sequence number of the received RLC AMD PDU. After checking the data packet, the RLC layer generates a retransmission indication indicating which data has been correctly received and which data needs to be retransmitted by the base station on the UTRAN side.
  • the retransmission indication (also referred to as a STATUS message) is similar to the definition and content of the STATUS PDU in the RLC in the existing system, and may include, but is not limited to, the following:
  • ACK SUFI Positive acknowledgement information of the received AMD PDU
  • MMW SUFI-ACK mobile reception window acknowledgement information
  • the Relative List information ( Relative LIST SUFI) of the AMD PDU that was not received correctly.
  • the format of the acknowledgement information of the downlink RLC AMD PDU that has been correctly received is as shown in FIG. 4, and the LSN indicates the last transmission sequence number, which is used to indicate that the data of the transmission sequence number of the RLC AMD PDU before the LSN has been correctly received.
  • the List (list) information of the RLC AMD PDU that is not correctly received and the Relative List information of the RLC AMD PDU that is not correctly received indicate that the RLC AMD PDU is not correctly received, and the first information is given in the List information.
  • the UE In step 640, the UE generates a MAC-e PDU and transmits it.
  • the MAC-e sub-layer of the UE multiplexes the retransmission indication generated by the RLC in step 630 into the MAC-e PDU, and then transmits the retransmission indication to the base station through the E-DPCH of the HSUPA.
  • the process of generating the retransmission indication to the MAC-e PDU and the MAC-e PDU is as shown in FIG. 3.
  • a retransmission indication is added to indicate that the RLC layer of the UE side correctly receives the RLC AMD PDU.
  • a data block MAC-e PDU transmitted in the E-DPCHCH is generated.
  • DDI Data Description Indicator
  • a special value is added to the DDI for the corresponding retransmission indication, indicating that the corresponding MAC-es PDU is the RLC layer receiving status confirmation information.
  • Step 650 After receiving the MAC-e PDU sent by the UE, the base station on the UTRAN side resolves the retransmission indication in the MAC-e PDU. Since the UE multiplexes the retransmission indication in the MAC-e PDU, the base station on the UTRAN side can resolve the retransmission indication in the MAC-e PDU by performing a demultiplexing process as shown in FIG. 5. And obtaining, according to the acknowledgement information of the downlink RLC AMD PDU that has been correctly received in the retransmission indication, the UE receiving the RLC AMD PDU.
  • Step 660 The MAC layer in the base station refreshes the MAC layer cache according to the retransmission instruction that is solved in step 650, and retransmits the data packet that is not correctly transmitted in the buffer to the user equipment. Since in step 650, the base station can already know that the UE receives the RLC AMD PDU, that is, the base station can know which RLC AMD PDUs have been correctly received by the base station, and which RLC AMD PDUs have not been correctly received by the UE.
  • the MAC-d PDU corresponding to the RLC AMD PDU that has been correctly received or retransmitted has reached the preset threshold, and the corresponding MAC-d PDU is updated to the new data packet to be transmitted by the correspondence between the MAC-d PDU and the RLC AMD PDU;
  • the corresponding MAC-d PDU is sent to the UE through the correspondence between the MAC-d PDU and the RLC AMD PDU, and the data is saved in the MAC cache until received.
  • the indication that the UE has correctly received or the number of retransmission failures reaches a preset threshold.
  • the data that needs to be retransmitted is saved in the MAC layer of the base station, and the retransmission indication of the RLC AMD PDU is carried in the MAC-e PDU to the base station, so that the base station receives the MAC-e PDU and After the retransmission indication is parsed, the retransmission can be directly initiated in the base station, which greatly reduces the transmission delay. Therefore, the retransmitted data packet can also be a data packet carrying the real-time service.
  • the base station can directly initiate retransmission, the AMD PDU data buffer of the RLC layer can be released, and because the base station can quickly obtain information that the AMD PDU is correctly received, the size of the cache maintained in the base station is also smaller than the original. The caching of the RLC layer thus improves the overall processing power of the UTRAN and saves costs.
  • a downlink data retransmission system which has a base station and a user terminal.
  • the method includes: a storage unit that caches downlink data packets in the base station at the designated layer;
  • an update and retransmission unit configured in the base station, refreshing, in the specified layer, the data packet in the storage unit according to the retransmission indication, and resending the data packet that is not correctly transmitted to the user terminal;
  • the user terminal will retransmit the multiplex protocol data unit at the designated layer;
  • the user terminal generates a retransmission indication according to a result of checking the correctness of the received data packet at the radio link control RLC layer, and sends the retransmission indication to the base station;
  • the base station and the user terminal both include the designated layer, and the user terminal has the upper layer signaling multiplexed to the designated layer uplink protocol data unit at the designated layer, and the base station performs corresponding demultiplexing at the designated layer.
  • the designated layer is a medium access control MAC layer.
  • the downlink data packet is a radio link control RLC acknowledgement mode protocol data unit
  • the MAC encapsulates the RLC acknowledge mode protocol data unit into a MAC-d protocol data unit, where the RLC acknowledges the mode protocol data unit and the MAC-d Protocol data unit - corresponding.
  • the retransmission indication includes one of the following information or any combination thereof:
  • Orthogonal Frequency Division Multiplexing OFDM
  • Orthogonal Frequency Division Multiplexing system Orthogonal Frequency Division Multiplexing system
  • MIMO multiple input multiple output

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Description

无线通信下行数据重传方法及***
技术领域
本发明涉及无线通信技术领域， 特别涉及无线通信下行数据重传方 法及***。 背景技术
宽带码分多址（ WCDMA, Wideband Code Division Multiple Access ) 是国际电信联盟（ITU, International Telecommunications Union )接纳的 全球第三代移动通信的国际标准之一。 也可以说是最早投入商用的第三 代移动通信***， 同时是欧洲第三代移动通信***频分欢工 （FDD , Frequency Division Duplex )频段的标准。
WCDMA 是采用直接序列扩频（DSSS , Direct Sequence Spread Spectrum)技术的 CDMA***， 它通过扩频码将用户带宽扩展到 1000倍 以上， 将信道带宽扩大到 5MHz。 这样可以在很低信噪比的情况下以同样 的传输速率可靠地传送信息。 大大增强抗干扰能力、 实现码分多址， 可 以支持各种不同的用户数据速率。
WCDMA最早的协议版本是 R99, 在该版本中， 上行和下行业务的 承载都是基于专用信道， 能够达到的数据传输速率均为 384Kbps。但是随 着用户对传输高速数据的需求越来越高， WCDMA标准制定组织随后陆 续推出了 R4、 R5、 R6三个阶段的网络协议， 引入了高速下行分组接入 ( HSDPA, High Speed Downlink Packet Access )技术与高速上行分组接 入（HSUPA, High Speed Uplink Packet Access )技术， 分别能够提供高达 14.4Mbps和 5.76Mbps的峰值速率， 同时， 也大大提高了频谱效率。
在 R5版本中 HSDPA的主要特点包括： 采用 2ms的短帧， 在物理层 采用混合自适应重传请求（ HARQ, Hybrid Automatic Repeat Request )和 自适应调制和编码 ( AMC, Adaptive Modulation and Coding )技术， 引入 了高阶调制以提高频谱利用率， 通过码分和时分实现各个用户设备（UE, User Equipment ) 的共享信道调度。 HARQ技术要求基站节点 （NodeB ) 发送了数据给 UE后 , 需要获取 UE反馈确认 ACK (确认） /NACK (无 确认 )的应答数据来判断 UE是否已正确接收该数据， 以便决定是重传数 据还是新发数据。 HSDPA在下行增加了两个物理信道， 一个是高速物理 下 亍共享信道 ( HS-PDSCH , High Speed Physical Downlink Shared Channel ) , 用于承载用户的数据信息， 另一个是高速共享控制信道 ( HS-SCCH, High Speed Shared Control Channel ), 用于承载解调伴随数 据信道 HS- PDSCH所需的信令。 另外， HSDPA在上行增加了一个高速专 用物理控制信道 ( HS-DPCCH, High Speed-Dedicated Physical Control Channel ), 该信道用于承载反馈下行数据帧通过高速物理下行共享信道 ( HS-PDSCH, High Speed Physical Downlink Shared Channel )接收正确 与否的信息 ACK/NACK, 或者用于反馈信道质量指示 （CQI , Channel Quality Indicator )。同时，在媒体访问控制（ MAC , Medium Access Control ) 层也增加了高速媒体访问控制 （MAC-hs , Medium Access Control-high speed )子层来支持 HSDPA的流控， 快速调度 /优先权管理， HARQ和传 输格式资源指示 (TFRI, Transport Format and Resource Indicator)选捧。 MAC-hs位于 MAC层的另一子层 MAC-d ( d指专用）之下，物理层之上。
在 R6版本中 HSUPA的主要特点包括： 采用 2ms短帧或 10ms帧， 在物理层釆用 HARQ, 上行基站快速调度技术等。 为了实现用户上行数 据的高效率传输， HSUPA要求为用户新增两个上行物理信道， 一个是传 输数据的增强专用物理数据信道 （ E - DPDCH , Enhance - Dedicated Physical Data Channel ), 另一个是传输伴随物理层信令的增强专用物理控 制信道（E - DPCCH, Enhance - Dedicated Physical Control Channel ), 后 者为前者解调提供伴随的信令。 为了控制用户的上行传输速率， 下行信 道增加了绝对授权信道 (E-AGCH, Enhance - Absolute Granted Channel)和 相对授权信道 (E-RGCH, Enhance - Relative Granted Channel), 绝对授权 信道只在服务无线连接小区中存在， 用于指示用户上行可以传输的最大 传输速率， 调节的频率比较低； 相对授权信道在服务无线连接和非服务 无线连接小区中都可以存在， 用于指示用户按一定步距调整上行传输速 率， 调整的频率比较高， 最高可达每 2ms—次。 在下行信道中还增加了 指示上行进程数据传输是否正确的信道， 用于告诉用户发送的数据是否 正确， 如果不正确， 用户将发起重传， 否则用户发送新的数据。 除了物 理层增加信道之外， 为了配合 HSUPA, 再在 MAC层中引入 MAC-e ( e 指增强）和 MAC- es两个子层， 以支持 HARQ和快速调度， 同时， 可以 利用 MAC- e协议数据单元（ MAC-e PDU, MAC-e Protocol Data Unit )承 载信令并在基站的 MAC-e层将这个信令读取出来。 在 MAC-e子层中形 成 MAC-e PDU时， 可以复用信令 MAC-es PDU, 也就是将多个 MAC-es PDU整合成 MAC-e PDU。 MAC-e和 MAC-es处于物理层和 MAC-d之间。 在 UE侧， 将对应增强专用信道（ E - DCH , Enhance - Dedicate Channel ) 的不同 MAC-d流的数据合并到一起， 传给物理层； 在通用陆地无线接入 网 （ UTRAN, Universal Terrestrial Radio Access Network )侧， 将来自物 理层的数据才艮据重传的次数进行排序， 并分解为不同的 MAC-d流。
WCDMA 协议结构如图 1 所示， 在物理层之上， 是媒体接入控制 ( MAC )层、 无线链路控制 （RLC, Radio Link Control )层以及其他高 层。 在 WCDMA***中的确认模式（AM, Acknowledged Mode )下， 如 果数据出现传输错误， 就通过重传来纠正。 当物理层重传次数达到*** 给定的最大物理层重传次数， 而物理层仍然没有正确接收到数据时， 为 了进一步保障数据传输的正确性， 防止物理层的 HARQ传输错误， 接收 端 RLC层根据接收到的 RLC协议数据单元 （ PDU, Protocol Data Unit ) 的序号状况请求 RLC层重传，发送端 RLC层接收到此请求就会启动 RLC 层重传。 也就是说， 在物理层重传失败时， ***需要启动 RLC层， 甚至 更高层的重传。
其中， RLC层的传输模式请参考文献 3GPP TS 25.322:《RLC Protocol Specification^ RLC协议明细）V6.4.0与 3GPP TS 25.301: 《Radio Interface Protocol Architecture》（无线接口协议体系） V6.3.0。
目前，在 WCDMA***中，物理层和部分 MAC层位于基站内， RLC 层及以上更高层位于无线网络控制器（ RNC, Radio Network Controller, ) 内， 基站和无线网絡控制器之间有标准的接口数据传输方式。 在 AM模 式下， 如果物理层不能通过重传纠正数据的传输错误， 就需要由 RLC层 启动重传来保证业务数据正确传输。 下行传输的 RLC层重传过程为： 1 )在 UTRAN端， RLC层将从高层传过来的 RLC 业务数据单元 ( SDU, Service Data Unit ) 经过分割或者是合并生成大小相等的 RLC AMD PDU (确认模式 RLC PDU )。 其中 RLC AMD PDU的大小是由参数 AMD RLC size (确认模式下的 RLC大小）决定的。 得到的 AMD PDU就 被放入重传的緩存区等待发送。
2 )在 UE端， MAC层将接收到 MAC PDU去掉 MAC层的数据头之 后得到 RLC层的 PDU, 将之传给 RLC层。 在 RLC层， 通过 AMD PDU 的序号来确认 LC AMD PDU是否被正确接收。 如果正确接收， 则发送 确认信息给对等的 UTRAN RLC层， 如果没被正确接收， 需要重传， 则 发送请求重发的信息给对等的 UTRAN RLC层。
3 )在 UTRAN端， RLC层根据接收到的 UE确认信息或者是重发请 求作不同的操作。 如果接收到确认， 就不再发送此 RLC AMD PDU, 并 刷新 RLC AMD PDU的数据緩存。 如果接收到重发请求， 并且没有超过 RLC层重发次数， 则将需要重传的 RLC AMD PDU放入重传的緩存区中 等待发送， 该数据块将重新传给基站， 由基站的物理信道承载给 UE。
在实际应用中， 上述方案会造成重传时延长以及 RNC的 RLC层緩 存量大。
其主要原因在于， 在现有的 RLC重传协议中， 由于反馈信息的定义 是在 RLC层上完成的，因此发送端在 RLC层才可以解析出接收端的接收 反馈信息。 具体到下行的 RLC层重传， UE端先将接收到的 RLC AMD PDU存放在接收的 RLC缓存'区中， 直至一个完整的 RLG SDU对应的 RLC AMD PDU全部接收到。 RLC层通过 RLC AMD PDU的序号判断该 RLC SDU对应的全部 RLC AMD PDU是否被正确接收。 如果出现 RLC AMD PDU丟失， 则通过 UE发送端发送的重传指示请求重发。 然后在 UTRAN接收端的 RLC层， 将 UE发送过来的重传指示的内容分析出来， 判断此 RLC AMD PDU是否需要重发。 这个过程需要 Iub/Iur接口传递信 息， 因此花费的时间比较长。 由于 RLC处于 RNC中， 因此 RLC的重传 涉及 R C处理， 基站处理以及二者之间的数据传输， 过多的中间环节处 理同样导致了传输时间延长。
另外， 如果 UTRAN的 RLC层没有接收到 UE对等的 RLC层所反馈的数 据已经正确接收的状态报告， 就需要在 RLC层保留这些数据， 对于承载 高速数据业务流来说， 很容易导致 RNC 的緩存资源紧张， 并且影响其处 理能力。
发明内容
本发明的主要目的在于提供一种无线通信***中的下行数据重传方 法， 使得重传时间大大减少， 数据包在 RNC侧的緩存量大大减少， RNC 的处理能力得到提升。
根据本发明提供的一种无线通信下行数据重传方法， 包括以下步骤： 基站将下行数据包在指定层缓存后向用户设备发送；
所述用户端在无线链路控制 RLC层根据对所接收数据包正确性的检 查结果生成重传指示， 该用户端在指定层将该重传指示复用到该指定层 的协议数据单元， 并向所述基站发送；
所述基站在指定层收到所述协议数据单元后解出其中的重传指示， 并由该指定层按该重传指示刷新所述指定层緩存并将该緩存中未被正确 传输的数据包重新向所述用户端发送；
所述基站和用户端中均包含所述指定层， 该用户端在指定层具有将 上层信令复用到该指定层上行协议数据单元的功能， 该基站在指定层具 有相应的解复用功能。
所述指定层是 MAC层；
RLC层向指定层发送数据以及检查所接收数据包正确性。
在所述 MAC层中的 MAC-e子层实现复用、解复用重传指示的功能。 所述下行数据包是 RLC确认模式协议数据单元， 所述 MAC将 RLC 确认模式协议数据单元封装成 MAC-d协议数据单元后緩存， 其中， RLC 确认模式协议数据单元与 MAC-d协议数据单元——对应；
当所述 MAC层通过所述重传指示获知 RLC确认模式协议数据单元 未被正确传输， 则将所述 MAC层緩存中该 RLC确认模式协议数据单元 所对应的 MAC-d协议数据单元重新向所述用户端发送。
所述重传指示中可包含以下信息之一或其任意组合：
已被正确接收的下行 RLC确认模式协议数据单元的确认信息、 移动 接收窗确认信息、 未被正确接收的 RLC确认模式协议数据单元的列表信 息、 以及未被正确接收的 RLC确认模式协议数据单元的相对列表信息。
所述 MAC-e协议数据单元承载于高速上行分组接入的上行专用增强 数据信道。
更适宜地， 在所述刷新 MAC层缓存的步骤中， 将所述 MAC层缓存 中所述重传指示确认为已被正确接收或重传失败次数达到预置门限的数 据包更新为,待传的新数据包：
更适宜地， 所述数据包为承载实时业务的数据包。
更适宜地， 所述重传数据为高速下行分组接入数据。
所述无线通信***是宽带码分多址***、 正交频分复用***、 多输 入多输出***及其演进***中之一。
根据本发明还提供一种无线通信下行数据重传***， 具有基站及用 户终端， 包括：
存储单元， 在指定层緩存基站中的下行数据包；
更新及重传单元， 设置在基站中， 在所述指定层根据重传指示刷新 所述存储单元中的数据包并将未被正确传输的数据包重新向所述用户终 端发送；
用户终端在指定层将重传指示复用协议数据单元； ； 所述用户终端在无线链路控制 RLC层根据对所接收数据包正确性的 检查结果生成重传指示， 并向所述基站发送；
所述基站和用户终端中均包含所述指定层， 该用户终端在指定层具 有将上层信令复用到该指定层上行协议数据单元， 所述基站在指定层进 行相应的解复用。
所述指定层是媒介访问控制 MAC层。
所述下行数据包是无线链路控制 RLC确认模式协议数据单元， 所述
MAC将 RLC确认模式协议数据单元封装成 MAC_d协议数据单元后緩存，其 中， RLC确认模式协议数据单元与 MAC- d协议数据单元——对应。
所述重传指示包含以下信息之一或其任意组合：
已被正确接收的下行 RLC 确认模式协议数据单元的确认信息、 移动 接收窗确认信息、 未被正确接收的 RLC确认模式协议数据单元的列表信 息、 以及未被正确接收的 RLC确认模式协议数据单元的相对列表信息。
与现有技术的主要区别在于，在本发明的技术方案中，把原先在 RNC 中实现的 RLC层的重传功能下移到基站中的 MAC层实现， 利用 HSUPA 的 MAC-e PDU携带用户设备反馈的重传指示。 基站将来自 RLC层的下 行数据包在 MAC层缓存后发向用户设备， 用户设备的 MAC-e子层将重 传指示复用在 MAC-e PDU中发向基站， 基站的 MAC- e子层从 MAC-e PDU中解出重传指示并据此刷新 MAC层緩存并重传错误的数据包。
采用本发明的技术方案， 重传速度大大加快， 效率明显提高。 因为 把重传从 RNC移到基站实现， 所以整个重传过程所涉及的路径缩短了， 现有技术中重传路径的两端是 RNC和 UE, 中间还要经过基站的中转， 使用本发明后路径的两端是基站和. UE, 在缩短路径的同时还取消了下行 RLC层重传时基站在 Iub口和 RNC交互处理的延时， 这使得数据重传时 间接近空口的数据传输时延， 从而大大节省重传时间， 大大减小了下行 传输的时延， 有利于时延敏感业务的服务质量 QoS保障， 提高用户满意 度， 可减少或消除声音迟滞、 图像不连续等问题。
采用本发明的技术方案, RNC侧的 RLC层缓存可以取消。 现有技术 中的 RLC层重传机制导致了 RNC的 RLC层緩存量比较大， 对于承载高 速数据业务流来说， 可能会导致 RNC緩存资源紧张。 因为如果 RNC的 RLC层没有接收到对等的用户 UE RLC层反馈的数据已经正确接收的状 态报告， 将保留这些数据， 在高速数据业务下， 很容易导致 R C的緩存 资源紧张和处理能力受限。如果在基站内实现 RLC层的重传功能，则 RLC 层的 AMD PDU数据緩存可以释放， 由基站内的缓存来代替。 由于基站 能够快速获取 AMD PDU是否正确接收的信息， 因此可以快速释放接收 正确的数据块緩存， 使得基站实际需要緩存的对应 AMD PDU数据量大 大减小了， 因此总体可以提升 UTRAN的设备处理能力并节省成本。
本发明的技术方案简化了协议架构。 因为在基站实现 "RLC层重传" 的功能， UTRAN侧只需进行物理层的重传， 所以可以筒化协议架构。 同 时基站实现 "RLC层重传" 的功能， 减小了基站和 RNC之间的数据重传 带来的带宽消耗， 提高 Iub接口的有效利用率。
本发明的技术方案可承载实时业务。 因为使用本发明的方案后传输 时延大大减少， 使得现有的非确认模式承载业务可以变为通过确认模式 承载， 比如实时业务。 通过确认模式承载， 这些业务的传输可靠性可以 大大提 Ϊ¾。 附图说明
图 1是现有技术中 WCDMA的协议结构图；
图 2是 RLC AMD PDU的结构图；
图 3是本发明的优选实施例中 UE侧将重传指示复用到 MAC - e PDU 以及 MAC - e PDU生成过程的示意图；
图 4是本发明的优选实施例中重传指示中的 ACK SUFI结构示意图； 图 5是本发明的优选实施例中基站解复用 UE发送的 MAC - e PDU 的过程示意图；
图 6是根据本发明的优选实施例的 HARQ重传的方法流程图； 图 7为根据本发明的优选实施例的下行数据重传***构成示意图。 具体实施方式
为使本发明的目的、 技术方案和优点更加清楚， 下面将结合附图对 本发明作进一步地详细描述。
本发明的核心在于， 将 RLC层的重传下移到基站内部， 使得数据重 传时间接近于空口的数据传输时延， 从而大大节省了重传时间， 可以达 到承载实时业务的要求。 同时， RLC层的重传下移使得緩存在 RNC侧的 数据包大大减少， 节约了 RNC緩存资源， 并且提升了 RNC的处理能力。 具体地说， 就是在基站中设立用于存储 MAC-d PDU的 MAC緩存， 并将 RLC层中的重传数据存储到基站中的 MAC緩存中。 MAC緩存中的数据 再通过物理层和空中接口传送给 UE。 UE将接收到的数据经过物理层和 MAC层处理后， 传送给 RLC层， 由 LC层判断从基站中发送的数据是 否被正确接收，并生成重传指示，传送给 UE的 MAC - e层。 UE的 MAC - e层将 RLC层来的数据和重传指示复用成 MAC - e PDU, 通过物理层 和空中接口发送给基站。 基站将接收到的数据通过物理层处理后传送给 基站的 MAC - e层， 再由 MAC - e层对该数据进行解复用， 得到 UE的 重传指示， 并通过重传指示的内容判断哪些数据已被 UE正确接收，哪些 数据需要重发。 将缓存内已经正确接收的数据更新为新的数据， 对于没 有正确接收的数据， 基站通过下行 HSDPA发起数据的空口快速重传， 并 同时保留该数据在缓存中，直至接收到 UE已经正确接收的指示或者重传 失败次数达到预置门限时， 才将数据包更新为待传的新数据包。
本发明的实施例是应用于 WCDMA***中 HSDPA的数据重传， 参 照图 6。
步驟 610中， UTRAN侧在基站中设立用于存储 MAC-d PDU的 MAC 緩存， 并将 RLC层中的重传数据存储到基站中的 MAC緩存中。 由于存 储在 RLC中的数据包是 RLC AMD PDU, 所以， 基站中的 MAC必须先 将 RLC AMD PDU封装成 MAC-d PDU后缓存，在本实施例中 RLC AMD PDU与 MAC-d PDU是——对应的关系。 本领域的普通技术人员可以理 解， RLC层的 PDU与緩存的 PDU也可以是一对多或多对一的关系, 而 处理方法并不偏离本发明的精神。
由于基站侧包含物理层和部分 MAC层， 而 RLC层以及更高层在基 站侧没有， 上行数据要传递到 RNC侧才可以得到 RLC层及更高层的处 理， RNC与基站的信息交互需要通过 Iub/Iur接口， 因此， 如果重传的数 据无需通过拥有 RLC层的 R C传送给基站， 再由基站通过物理层和空 中接口发送给 UE, 而是直接由基站发送给 UE, 可以减少传输时延。 同 时，由于重传数据从 R C的 RLC层緩存中下移到基站的 MAC层缓存中， 緩解了 R C緩存资源紧张的问题。 即使在高速数据业务下， 也不容易导 致 RNC的緩存资源紧张和处理能力受限。
步骤 620， UTRAN侧将 RLC层中的重传数据緩存到基站中的 MAC 层后， 基站将重传数据传送给物理层， 由物理层通过空中接口将数据发 送给 UE。
步驟 630, UE的 RLC层检查数据包的正确性并生成重传指示。 UE 在接收到 UTRAN侧的基站所发送的数据包后， 在 RLC层对该数据包的 正确性进行检查。由于在 RLC层接收到的数据包是 RLC AMD PDU, RLC AMD PDU的结构如图 2所示，其中携带的传输序列号表明了数据包传输 的顺序。 因此， 在 RLC中就可以根据接收到的 RLC AMD PDU的传输序 列号对数据包传输的正确性进行检查。 RLC 层对该数据包进行检查后， 生成重传指示，指明哪些数据已被正确接收，哪些数据需要 UTRAN侧的 基站重发后。
重传指示（又可称为 STATUS消息）和现有***中 RLC中的 STATUS PDU的定义和内容类似， 可以包括并不局限于以下内容：
收到的 AMD PDU的 positive acknowledgement信息 （ ACK SUFI ); 移动接收窗确认信息 （ MRW SUFI— ACK );
表明没有正确接收的 AMD PDU的 List信息 （ LIST SUFI );
没有正确接收的 AMD PDU 的 Relative List信息（ Relative LIST SUFI)。
其中， 已被正确接收的下行 RLC AMD PDU的确认信息的格式定义 如图 4所示， LSN表示最后传输序列号， 用于表示 RLC AMD PDU的传 输序列号在 LSN之前的数据都已被正确接收。未被正确接收的 RLC AMD PDU的 List(列表）信息和未被正确接收的 RLC AMD PDU的 Relative List (相对列表）信息都表明了没有正确接收到的 RLC AMD PDU, List信息 中给出第一个未正确接收的 RLC AMD PDU的传输序列号和后面持续错 误的 RLC AMD PDU的数目； Relative List表明了第一个错误的 RLC AMD PDU的传输序列号，以及和下一个错误的 RLC AMD PDU的距离（间隔）。
步骤 640, UE生成 MAC - e PDU并发送。 UE的 MAC一 e子层将步 骤 630中 RLC生成的重传指示复用到 MAC - e PDU后， 通过 HSUPA的 E - DPDCH发送给基站。 重传指示复用到 MAC - e PDU 以及 MAC - e PDU的生成过程如图 3所示，在现有的 HSUPA基础上，增加重传指示来 指明 UE侧 RLC层正确接收 RLC AMD PDU的情况。 通过此重传指示和 其他 MAC-es PDU 复用， 生成在一个在 E - DPDCH 内传输的数据块 MAC-e PDU。并且在 MAC-es PDU的数据描述指示（ DDI, Data Description Indicator )定义中， 增加一种特殊值。 DDI是 MAC-e数据包包头， 用来 区别逻辑信道， MAC-d流和一个 MAC-es PDU中级联的 MAC-d PDU的 大小。 在 DDI中增加一种特殊值（比如 0 ), 用于对应重传指示， 表示其 对应的 MAC-es PDU为 RLC层接收状态确认信息。
步骤 650， UTRAN侧的基站接收到 UE发送的 MAC - e PDU后， 解 出 MAC - e PDU中的重传指示。由于 UE将重传指示复用在 MAC - e PDU 中， 因此 UTRAN侧的基站通过解复用过程， 如图 5所示， 可以将 MAC - e PDU中的重传指示解析出来。并根据重传指示中的已被正确接收的下 行 RLC AMD PDU的确认信息获知 UE接收 RLC AMD PDU的情况。
步骤 660， 基站中的 MAC层根据在步骤 650中解出的重传指示刷新 MAC层緩存并将该緩存中未被正确传输的数据包重新向所述用户设备发 送。 由于在步骤 650中 , 基站已经可以获知 UE接收 RLC AMD PDU的 情况， 也就是说， 基站可以知道哪些 RLC AMD PDU已被基站正确接收， 哪些 RLC AMD PDU尚未被 UE正确接收。 对于已被正确接收或重传失 败次数达到预置门限的 RLC AMD PDU,通过 MAC - d PDU与 RLC AMD PDU的对应关系， 将与之对应的 MAC - d PDU更新为待传的新数据包； 对于尚未被 UE正确接收的 RLC AMD PDU, 同样通过 MAC - d PDU与 RLC AMD PDU的对应关系， 将与之对应的 MAC - d PDU发送给 UE, 并且在 MAC緩存中保存该数据， 直至接收到 UE已经正确接收的指示或 者重传失败次数达到预置门限。
本实施例通过在基站的 MAC层保存了需要重传的数据， 并且在 UE 侧将 RLC AMD PDU的重传指示携带在 MAC-e PDU中传给基站， 使得 基站在接收到 MAC-e PDU并解析出其中的重传指示后，可以直接在基站 内发起重传， 大大减少了传输时延， 因此， 重传的数据包也可以是承载 实时业务的数据包。 另外， 由于在基站可以直接发起重传， 因此， RLC 层的 AMD PDU数据緩存可以被释放，而且，因为基站能够快速获取 AMD PDU是否正确接收的信息， 使得在基站中维护的緩存大小也小于原 RLC 层的緩存， 因此总体提升了 UTRAN的设备处理能力并节省了成本。
另外， 根据本发明还提供一种下行数据重传***， 具有基站及用户 终端， 参照图 7包括： 存储单元， 在指定层緩存基站中的下行数据包；
更新及重传单元， 设置在基站中， 在所述指定层根据重传指示刷新 所述存储单元中的数据包并将未被正确传输的数据包重新向所述用户终 端发送；
用户终端在指定层将重传指示复用协议数据单元；
所述用户终端在无线链路控制 RLC层根据对所接收数据包正确性的 检查结果生成重传指示， 并向所述基站发送；
所述基站和用户终端中均包含所述指定层， 该用户终端在指定层具 有将上层信令复用到该指定层上行协议数据单元， 所述基站在指定层进 行相应的解复用。
所述指定层是媒介访问控制 MAC层。
所述下行数据包是无线链路控制 RLC确认模式协议数据单元， 所述 MAC将 RLC确认模式协议数据单元封装成 MAC-d协议数据单元后缓存，其 中 , RLC确认模式协议数据单元与 MAC-d协议数据单元——对应。
所述重传指示包含以下信息之一或其任意组合：
已被正确接收的下行 RLC确认模式协议数据单元的确认信息、 移动 接收窗确认信息、 未被正确接收的 RLC确认模式协议数据单元的列表信 息、 以及未被正确接收的 RLC确认模式协议数据单元的相对列表信息。
本领域的普通技术人员可以理解， 上述实施例虽然是以 WCDMA为 基础进行说明的， 但也可以容易地将本发明的技术方案应用到相似的无 线通信***， 如正交频分复用 （OFDM, Orthogonal Frequency Division Multiplexing )***、多输入多输出（ MIMO, Multiple Input Multiple Output ) ***等。
虽然通过参照本发明的某些优选实施例， 已经对本发明进行了图示 和描述， 但本领域的普通技术人员应该明白， 可以在形式上和细节上对 其作各种改变， 而不偏离本发明的实质和范围。

Claims

权 利 要 求
1. 一种无线通信下行数据重传方法， 其特征在于， 包括以下步骤： 基站将下行数据包在指定层缓存后向用户终端发送；
所述用户终端在无线链路控制 RLC层根据对所接收数据包正确性的 检查结果生成重传指示， 该用户终端在指定层将该重传指示复用到该指 定层的协议数据单元， 并向所述基站发送；
所述基站在指定层收到所述协议数据单元后解出其中的重传指示， 并由该指定层按该重传指示刷新所述指定层緩存并将该緩存中未被正确 传输的数据包重新向所述用户终端发送；
其中， 所述基站和用户终端中均包含所述指定层， 该用户终端在指 定层具有将上层信令复用到该指定层上行协议数据单元的功能， 该基站 在指定层具有相应的解复用功能。
2. 根据权利要求 1所述的方法， 其特征在于， 所述指定层是媒介访 问控制 MAC层；
RLC层向指定层发送数据以及检查所接收数据包正确性。
3. 根据权利要求 2所述的方法， 其特征在于， 在所述 MAC层中的 MAC-e子层实现复用、 解复用重传指示的功能。
4. 根据权利要求 3所述的方法， 其特征在于， 所述下行数据包是无 线链路控制 RLC确认模式协议数据单元， 所述 MAC将 RLC确认模式协 议数据单元封装成 MAC-d协议数据单元后緩存， 其中， RLC确认模式协 议数据单元与 MAC- d协议数据单元——对应；
如果所述 MAC层通过所述重传指示获知 RLC确认模式协议数据单 元未被正确传输， 则将所述 MAC层緩存中该 RLC确认模式协议数据单 元所对应的 MAC-d协议数据单元重新向所述用户终端发送。
5. 根据权利要求 4所述的方法， 其特征在于， 所述重传指示中包含 以下信息之一或其任意组合：
已被正确接收的下行 RLC确认模式协议数据单元的确认信息、 移动 接收窗确认信息、 未被正确接收的 RLC确认模式协议数据单元的列表信 息、 以及未被正确接收的 RLC确认模式协议数据单元的相对列表信息。
6. 根据权利要求 3所述的方法， 其特征在于， 所述 MAC-e协议数 据单元承载于高速上行分組接入的上行专用增强数据信道。
7. 根据权利要求 2所述的方法， 其特征在于， 在所述刷新 MAC层 缓存的步骤中，将所述 MAC层缓存中所述重传指示确认为已被正确接收 或重传失败次数达到预置门限的数据包更新为待传的新数据包。
8. 根据权利要求 1所述的方法， 其特征在于， 所述数据包为承载实 时业务的数据包。
9. 根据权利要求 1至 8中任一项所述的方法， 其特征在于， 所述重 传数据为高速下行分组接入数据。
10. 才艮据权利要求 1至 8中任一项所述的方法， 其特征在于， 所述 无线通信***为以下***之一：
宽带码分多址***、 正交频分复用***、 多输入多输出***及演进 ***。
11、一种无线通信下行数据重传***， 包括基站及用户终端， 其特征 在于， 还包括：
存储单元， 在指定层缓存基站中的下行数据包；
更新及重传单元， 设置在基站中， 在所述指定层根据重传指示刷新 所述存储单元中的数据包并将未被正确传输的数据包重新向所述用户终 端发送；
用户终端在指定层将重传指示复用协议数据单元；
所述用户终端在无线链 控制 RLC层根据对所接收数据包正确性的 检查结果生成重传指示， 并向所述基站发送；
所述基站和用户终端中均包含所述指定层， 该用户终端在指定层具 有将上层信令复用到该指定层上行协议数据单元， 所述基站在指定层进 行相应的解复用。
12、 根据权利要求 11所述的***， 其特征在于，
所述指定层是媒介访问控制 MAC层。
13、 根据权利要求 11所述的***， 其特征在于，
所述下行数据包是无线链路控制 RLC确认模式协议数据单元， 所述 MAC将 RLC确认模式协议数据单元封装成 MAC- d协议数据单元后緩存，其 中， RLC确认模式协议数据单元与 MAC- d协议数据单元——对应。
14、 根据权利要求 1 1所述的***， 其特征在于，
所述重传指示包含以下信息之一或其任意组合：
已被正确接收的下行 RLC确认模式协议数据单元的确认信息、 移动 接收窗确认信息、 未被正确接收的 RLC确认模式协议数据单元的列表信 息、 以及未被正确接收的 RLC确认模式协议数据单元的相对列表信息。
PCT/CN2006/002040 2005-08-29 2006-08-11 Methode et systeme de retransmission de donnees avec abaissement de couche dans une communication sans fil WO2007025454A1 (fr)

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