JP2010193394A - Radio transmission apparatus and radio transmission method - Google Patents

Abstract

A wireless transmission device and a wireless transmission method are provided that avoid an increase in processing delay time and the number of reception processing times and improve retransmission gain.
A transmission method determination unit 110 is based on a result of threshold determination between a CQI transmitted from a UE and a threshold, and a size relationship between the number of transport transport blocks and the number of transport blocks that can be processed by the UE. The transmission data dividing method is determined. The physical data size determination unit 112 determines a mapping method for a plurality of transport blocks to be transmitted based on the number of transmission transport blocks, the presence / absence of interleaving in the UE, and the division method determined by the transmission method determination unit 110. .
[Selection] Figure 3

Description

  The present invention relates to a radio transmission apparatus and radio transmission method to which HARQ (Hybrid Automatic Repeat reQuest) is applied.

  3GPP LTE (3rd Generation Partnership Project Long Term Evolution) employs MIMO (Multiple Input Multiple Output) technology, N-process SAW (Stop And Wait) HARQ, and asynchronous downlink HARQ transmission (retransmission interval). Is scheduled to be RTT (Round Trip Time) or more).

  Here, the N process SAW method will be described. First, the SAW method is a method for determining whether data to be transmitted is new or retransmission based on a determination result (ACK / NACK) of the receiver as shown in FIG. RTT until new transmission or retransmission is required. However, if transmission is possible only in RTT units, resources are wasted if resources can be allocated continuously in time.

  On the other hand, as shown in FIG. 2, the N process SAW method is a method of processing SAW in parallel in units of time, and associates a process number with the unit of processing in parallel. That is, in the case of asynchronous transmission, the process number is transmitted by CCH, and received data is distinguished. Performing a plurality of (N) SAW processes in this way is called an N process SAW.

In Non-Patent Document 1, as a transmission method when the transmission is changed from MIMO to SISO (Single Input Single Output) at the time of retransmission, that is, the number of transmission streams is reduced from 2 streams to 1 stream, the transmission format of MIMO is one time. A technique for transmitting each process for retransmission is disclosed. Since MIMO data can be transmitted even with SISO, data can be distinguished.
Samsung, Texas Instruments, Motorola, NTT DoCoMo, Nortel, “Indication of codewords in dynamic switching from DCI format 1A to DCI format 2” 3GPP TSG-RAN Working Group 1 # 53bis, Warsaw, Poland, June 30- July 4, 2008, R1-082694

  However, since retransmission is an N-process SAW, and only one transport block is transmitted per process, the number of processes is doubled when the MIMO is changed to SISO, and the processing delay time and the number of reception processes increase. There is. In addition, since a plurality of transport blocks cannot be transmitted in a subframe having a good CQI, there is a problem that a sufficient retransmission gain cannot be obtained.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a radio transmission apparatus and a radio transmission method that can avoid an increase in processing delay time and the number of reception processes and can improve retransmission gain.

  In the wireless transmission device of the present invention, the threshold determination result that the CQI transmitted from the communication partner is a predetermined threshold, and the number of transport blocks to be transmitted are in a magnitude relationship with the number of transport blocks that can be processed by the communication partner. A determination means for determining a transmission data division method, a determination means for determining a mapping method for a plurality of transport blocks to be transmitted based on the determined number of transport blocks and the determined division method, and a determination In accordance with the determined division method and the determined mapping method, a transmission means for transmitting transmission data is employed.

  In the wireless transmission method of the present invention, the threshold determination result that the CQI transmitted from the communication partner is a predetermined threshold and the number of transport blocks to be transmitted are in a magnitude relationship with the number of transport blocks that can be processed by the communication partner. A determination step for determining a transmission data division method, a determination step for determining a mapping method for a plurality of transport blocks to be transmitted based on the number of transport blocks to be transmitted and the determined division method, and a determination And a transmission step of transmitting transmission data according to the determined division method and the determined mapping method.

  According to the present invention, it is possible to avoid an increase in processing delay time and the number of reception processes, and to improve retransmission gain.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment)
FIG. 3 is a block diagram showing a configuration of radio transmitting apparatus 100 according to the embodiment of the present invention. In this figure, a reception RF unit 102 acquires a signal transmitted from a UE (User Equipment) as a communication partner via an antenna 101, and performs predetermined radio reception processing such as A / D conversion and down-conversion on the acquired signal. And output to the synchronizer 103.

  Synchronization section 103 performs synchronization processing on the signal output from reception RF section 102 and outputs the result to demodulation section 104. Demodulation section 104 demodulates the signal output from synchronization section 103 and separates the demodulation result into separation section 105. Output to.

  Separation section 105 separates the signal output from demodulation section 104 into DL-ACK, ULCCH (UpLink Control Channel), ULSCH (UpLink Shared Channel), ULCCH to ULCCH decoding section 106, and ULSCH to ULSCH decoding section 107. , DL-ACK is output to DL-ACK decoding section 108, respectively.

  The ULCCH decoding unit 106 decodes the ULCCH output from the separation unit 105 and outputs control information and CQI included in the decoded ULCCH to the ULSCH decoding unit 107 and the control unit 109.

  ULSCH decoding section 107 decodes ULSCH output from demultiplexing section 105 based on the control information output from ULCCH decoding section 106, performs CRC determination on the decoded data, and sends the CRC determination result to control section 109. Output. If there is no error as a result of the CRC determination, the decoded data is output.

  DL-ACK decoding section 108 decodes the DL-ACK output from demultiplexing section 105 and outputs the decoded ACK / NACK information to control section 109.

  Control section 109 outputs the CQI output from ULCCH decoding section 106 to transmission method determination section 110.

  In addition, the control unit 109 outputs the number of transport blocks and code blocks that can be processed by the UE to the transmission method determination unit 110. However, the number of transport blocks and code blocks that can be processed is known information.

  Further, the control unit 109 acquires downlink ACK / NACK information from the DL-ACK decoding unit 108, and if it is ACK, the next transmission is regarded as the first transmission, and the HARQ process number, the number of transport blocks, the number of code blocks, the SFN ( Super Frame Number or System Frame Number) and the subframe number are output to the transmission method determination unit 110. On the other hand, if it is NACK, the next transmission is retransmitted, and the HARQ process number, the number of transport blocks, the number of code blocks, the SFN of the first transmission, and the subframe number are output to the transmission method determination unit 110.

  In addition, the control unit 109 outputs the initial transmission SFN, the subframe number, the transport block size, and the number of code blocks of the HARQ process number that can be transmitted to the transmission method determination unit 110.

  In addition, when the control unit 109 acquires the HARQ process number that can be transmitted from the transmission method determination unit 110, the control unit 109 determines that the process number cannot be transmitted (during transmission). When new data is included in the transmittable HARQ process number notified from the transmission method determination unit 110, the SFN and subframe number of the first transmission are stored.

  Further, the control unit 109 outputs the transport block size of the target UE and the transport block size of another UE (UE other than the target UE) to the scheduling unit 111. Note that the target UE refers to a UE having the HARQ process number notified from the transmission method determination unit 110.

  In addition, the control unit 109 acquires the allocation result output from the scheduling unit 111, and outputs the number of retransmissions of the HARQ process to be transmitted, the transport block size, and QoS to the physical data size determination unit 112.

  In addition, the control unit 109 outputs the presence / absence of interleaving of the target UE to the physical data size determining unit 112.

  Also, the control unit 109 outputs control information (HACS process number control information (MCS: Modulation and Coding Scheme, RV: Redundancy Version and other information necessary for DLCCH and DLSCH encoding) to be transmitted to the physical data size determination unit 112.

  In addition, the control unit 109 outputs RB (Resource Block) assignment information of other UEs to the mapping unit 119.

  The transmission method determination unit 110 includes the initial transmission SFN of the transmittable HARQ process number output from the control unit 109, the subframe number, the transport block size, the number of code blocks, the CQI, the transport block size that can be processed by the UE, The number of transport blocks and the number of code blocks are acquired, and based on the acquired information, a combination of HARQ process numbers that can be transmitted is obtained and output to the control unit 109. One transport block is composed of a plurality of code blocks.

  The transmission method determination unit 110 also determines a transmission data division method (time division, frequency division, etc.) using the acquired information, and outputs the determined division method to the physical data size determination unit 112. Details of the division method will be described later.

  The scheduling unit 111 acquires the transport block size of the target UE and the transport block size of other UEs output from the control unit 109, assigns RBs to the UE based on the acquired transport block sizes, and The allocation result is output to the control unit 109. The RB assignment result is called RB assignment (RB assignment) and indicates which RB is assigned to which UE. Further, when information that transmits two or more transport blocks is input to one UE, the scheduling unit 111 preferentially allocates RBs to the UE.

  The physical data size determination unit 112 acquires the RB assignment output from the control unit 109, the number of retransmissions of the HARQ process to be transmitted, the transport block size, and the QoS. Also, information on the presence / absence of interleaving and control information to be transmitted (information necessary for DLSCH encoding such as MCS and RV or information transmitted on DLCCH) are acquired.

  The physical data size determination unit 112 obtains the total physical data size from the RB assignment, determines the physical data size of each HARQ process to be transmitted, the total physical data size, the transport block size to be transmitted, the number of retransmissions (or the number of retransmissions and an arbitrary number of retransmissions). The physical data size is determined by the following equation (1) using information indicating the importance of transmission such as (adjustment value) and QoS (or QoS and an arbitrary adjustment value). Alternatively, the physical data size may be obtained simply from the transport block size ratio.

Phy (N) = Roundup (Phy (T) * Trblk (N) / Trblk (T) * 1 / TxNum (R) ^ α) * (QoS (N) / QoS (R)) ^ β
if Phy (N) <Trblk (N) * γ
Phy (N) = Trblk (N) * γ
else Phy (R) = Phy (T) -Phy (N)
... (1)

  In the above equation (1), Phy (N) represents the physical data size of new data, Phy (R) represents the physical data size of retransmission data, and Phy (T) represents the total physical data size. Α represents an arbitrary value of 0.1 to 0.5, β represents an arbitrary value of 0.1 to 0.5, and γ represents a value of 1 to 3, respectively. Num (R) indicates the number of retransmissions of retransmission data.

  The physical data size determination unit 112 outputs a read request to the new data buffer unit 113 or the retransmission data buffer unit 114 based on the HARQ process number to be transmitted and the number of retransmissions output from the control unit 109, and the DLSCH encoding unit Selection information indicating whether processing is performed at 117 or 118 is output to the selection unit 115.

  Further, the physical data size determination unit 112 selects the output destination information, the physical data size, and the control information indicating to which of the DLSCH encoding units 117 and 118 the new data and retransmission data and their control information are output. Output to. Here, the control information indicates control information (MCS, RV, etc.) necessary for DLSCH encoding. When the DLSCH encoding unit 117 processes new data, control information necessary for encoding the new data is also output to the DLSCH encoding unit 117.

  Further, the physical data size determination unit 112 is based on the number of transport blocks to be transmitted (number of HARQ processes to be transmitted) output from the control unit 109, the presence or absence of interleaving, and the division method output from the transmission method determination unit 110. The mapping method is determined, and the determined mapping method is output to the mapping unit 119.

  Note that the method of obtaining the physical data size is not particularly problematic as long as the physical data size to be transmitted can be arbitrarily adjusted. In addition, a protection process is provided so that only the physical data size of one transport block does not increase (processing after the if statement in Expression (1)).

  The new data buffer unit 113 outputs new data to the selection unit 115 in accordance with the read request output from the physical data size determination unit 112, and the retransmission data buffer unit 114 outputs the read request output from the physical data size determination unit 112. The retransmission data is output to selection section 115 according to

  The selection unit 115 outputs the data output from the new data buffer or the retransmission data buffer, the physical data size, and the control information to the DLSCH encoding unit 117 or 118 according to the output destination information output from the physical data size determination unit 112. . Further, the control information output from physical data size determining section 112 is output to DLCCH encoding section 116.

  The DLCCH encoding 116 unit encodes the control information output from the selection unit 115 and outputs the encoded control information to the mapping unit 119.

  DLSCH encoding sections 117 and 118 encode the data output from selection section 115 and output the data to mapping section 119.

  The mapping unit 119 includes RB allocation information, CFI (Control Format Indicator or PCFICH: Physical Control Format Indicator Channel) and PHICH (Physical Hybrid-ARQ Indicator Channel) output from the control unit 109, and a physical data size determination unit 112. The data output from the DLCCH encoding unit 116, the DLSCH encoding unit 117, and the DLSCH encoding unit 118 are mapped based on the mapping method output from, and output to the modulation unit 120. Details of the mapping method will be described later.

  The modulation unit 120 modulates the signal output from the mapping unit 119 and outputs the modulated signal to the transmission RF unit 121. The transmission RF unit 121 converts the signal output from the modulation unit 120 into predetermined signals such as D / A conversion and up-conversion. Is transmitted from the antenna 101.

  Next, the mapping method described above will be specifically described. As the mapping method, as shown in FIG. 4, four patterns (hereinafter referred to as mapping methods A to D) are conceivable. Mapping method A performs mapping as shown in FIG. 4A. This method is applied when the UE supports only SISO and SIMO (Single Input Multiple Output), has one transport block to be transmitted, and has a single UE decoder.

  Mapping method B performs mapping as shown in FIG. 4B. That is, one transport block is mapped first, followed by another transport block. This method is applied when the UE supports only SISO and SIMO, the number of transmission transport blocks is plural, and the number of decoders of the UE is single.

  Mapping method C performs mapping as shown in FIG. 4C. That is, this method of mapping uniformly in the frequency axis direction from the ratio of the physical data size is used when the UE supports MIMO, the number of transmission transport blocks is plural, and there are plural UE decoders. Apply and frequency division allocation.

  Mapping method D maps as shown in FIG. 4D. That is, the outputs of the respective DLSCH encoding units 117 and 118 are mapped alternately. This method is interlaced if the outputs of the DLSCH encoding units 117 and 118 are mapped in order from the top, and this method is interleaved if randomly mapped. This is a method in which the UE supports MIMO, and there are a plurality of transmission transport blocks. This is applied when there are a plurality of UE decoders and interleaving is set, and frequency division and interleaving are selected. Note that it may be interleaved or interlaced. Further, the mapping method D has higher reception characteristics than the mapping method C (FIG. 4C) due to the effect of frequency dispersion.

  Although FIG. 4 shows a combination of new data and retransmission data, there may be cases of retransmission data and retransmission data.

  Next, the process of the transmission method determination unit 110 described above will be described with reference to FIG. In step (hereinafter abbreviated as “ST”) 501 in FIG. 5, the process number having the oldest initial transmission is selected from the SFN and subframe numbers, and the transport block size (indicated as “TrBlk” in the figure), The number of code blocks is counted, and the process proceeds to ST502.

  In ST502, it is determined whether the CQI is equal to or greater than a threshold value. If it is less than the threshold value (NO), the process proceeds to ST503, and if it is equal to or greater than the threshold value (YES), the process proceeds to ST504. In ST503, the division method is set as no division, and the process ends.

  In ST504, it is determined whether or not a transmittable HARQ process remains. If a transmittable HARQ process remains (YES), the process proceeds to ST505, and if a transmittable HARQ process does not remain (NO), ST508. Migrate to

  In ST505, the process number of the next oldest first transmission is selected from SFN and subframe number, the transport block size and the number of code blocks are counted (added), and the process proceeds to ST506.

  In ST506, the transport block size counted in ST505 is equal to or smaller than the transport block size that can be processed by the UE decoder, and the number of code blocks counted in ST505 is equal to or smaller than the number of code blocks that can be processed by the UE decoder. If it is below (YES), the process returns to ST504, and if it exceeds (NO), the process proceeds to ST507.

  In ST507, the transport block size and the number of code blocks counted in ST505 are deleted (subtracted), and the process returns to ST504.

  In ST508, the number of transport blocks to be transmitted is obtained from the number of HARQ processes to be transmitted, and it is determined whether the number of transport blocks to be transmitted is less than 1 or more than 1. If it is less than 1 (NO), the process proceeds to ST503, and if it is 1 or more (YES), the process proceeds to ST509.

  In ST509, it is determined whether or not the number of transport blocks that can be processed by the UE decoder is equal to or less. If processing is possible (YES), the process proceeds to ST510, and if processing is not possible (NO), the process proceeds to ST511.

  In ST510, the division method is determined to be frequency division, and the process ends. In ST511, the division method is determined to be time division, and the process is terminated.

  Next, the processing of the physical data size determination unit 112 described above will be described with reference to FIG. 6, in ST601, it is determined whether or not the number of transmission transport blocks is 1 (assuming that it is 1 or more). If 1 (YES), the process proceeds to ST602, and if 1 is exceeded (NO), the process proceeds to ST603. To do.

  In ST602, the mapping method A (FIG. 4A) is determined and the process ends.

  In ST603, the physical data size Phy (T) is obtained from the RB assignment. In ST604, the physical data size is obtained using the equation (1), and the process proceeds to ST605.

  In ST605, it is determined whether or not the division method is time division. If time division (YES), the process proceeds to ST606, and if frequency division (NO), the process proceeds to ST607.

  In ST606, the mapping method B (FIG. 4B) is determined, and the process ends.

  In ST607, the presence / absence of interleaving is determined, and if there is no (NO), the process proceeds to ST608, and if there is (YES), the process proceeds to ST609.

  In ST608, the mapping method C (FIG. 4C) is determined, and the process ends. In ST609, the mapping method D (FIG. 4D) is determined, and the process ends.

  In the receiving apparatus, if there are a plurality of decoders, a plurality of transport blocks are processed in parallel, and if a single decoder is used, a plurality of transport blocks are processed in time series.

  As described above, according to the present embodiment, when the CQI is good, a plurality of transport blocks are collectively transmitted in one subframe, thereby improving the time synthesis gain of HARQ. In addition, an increase in processing delay time and the number of reception processes can be avoided.

  Note that a plurality of channels may be applied to the transport block and code block to be transmitted. For example, it is conceivable to simultaneously transmit PCH (Paging Channel) and PDSCH (Physical Downlink Shared Channel) by the transport block.

  Even if the UE supports only SISO or SIMO, the number of processing codes increases when the processing capability is high, such as the number of processing clocks of the UE is high. Transmission data may be transmitted by frequency division.

  The radio transmission apparatus and radio transmission method according to the present invention can be applied to a mobile communication system such as 3GPP LTE.

Diagram for explaining the SAW system Diagram for explaining N-process SAW method The block diagram which shows the structure of the radio | wireless transmitter which concerns on embodiment of this invention Diagram for explaining RB allocation method FIG. 3 is a flowchart for explaining the processing of the transmission method determination unit shown in FIG. FIG. 3 is a flowchart for explaining processing of the physical data size determining unit shown in FIG.

DESCRIPTION OF SYMBOLS 101 Antenna 102 Reception RF part 103 Synchronization part 104 Demodulation part 105 Separation part 106 ULCCH decoding part 107 ULSCH decoding part 108 DL-ACK decoding part 109 Control part 110 Transmission method determination part 111 Scheduling part 112 Physical data size determination part 113 New data buffer Unit 114 retransmission data buffer unit 115 selection unit 116 DLCCH encoding unit 117, 118 DLSCH encoding unit 119 mapping unit 120 modulation unit 121 transmission RF unit

Claims (2)

A transmission data dividing method based on a threshold determination result that the CQI transmitted from the communication partner is a predetermined threshold, and the magnitude relationship between the number of transport blocks to be transmitted and the number of transport blocks that can be processed by the communication partner Determining means for determining
Determining means for determining a mapping method of a plurality of transport blocks to be transmitted based on the number of transport blocks to be transmitted and the determined division method;
Transmission means for transmitting transmission data according to the determined division method and the determined mapping method;
A wireless transmission device comprising: A transmission data dividing method based on a threshold determination result that the CQI transmitted from the communication partner is a predetermined threshold, and the magnitude relationship between the number of transport blocks to be transmitted and the number of transport blocks that can be processed by the communication partner A determination step of determining
A determination step of determining a mapping method of a plurality of transport blocks to be transmitted based on the number of transport blocks to be transmitted and the determined division method;
A transmission step of transmitting transmission data according to the determined division method and the determined mapping method;
A wireless transmission method comprising:

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