WO2010115295A1 - Method for requesting retransmission, method for retransmission and devices thereof - Google Patents

Abstract

A method for requesting retransmission, method for retransmission and the corresponding transmitter, receiver and system are provided. The method for requesting retransmission includes the following steps: signals from the transmitter are received and whether retransmission is needed is judged; the indication information of whether the transmitter needs to execute retransmission is fed back in a main feedback channel; if retransmission is needed, then retransmission enhancement information is fed back in a second feedback channel associated with the main feedback channel, and the retransmission enhancement information is used for improving the reception quality or the transmission efficiency of retransmission signals. With the technical solution, the quality and efficiency of retransmission can be effectively improved.

Description

 Request retransmission method, retransmission method and device thereof

 The field of wireless transmission of the present invention particularly relates to a request retransmission method, a retransmission method, and a device thereof. Background technique

 In current standards (such as WiMAX and LTE), only one hybrid retransmission request (HARQ) feedback channel is supported for each transmission. This feedback channel can only be used for feedback "ACK" (no retransmission required) and "NACK" " (requires retransmission). No additional information is allowed along with "NACK" - feedback.

 The current HARQ is based on a transport block (TB). For each received TB and associated

HARQ information, HARQ processing should attempt to decode the data in the soft buffer. If the data in the soft buffer is successfully decoded, an acknowledgment (ACK) of positive data is generated in this HARQ process. Otherwise, an acknowledgment (NACK) for the data is generated in this HARQ process.

 For each transmitted TB and associated HARQ information, if an acknowledgment (ACK) for the data is received in this HARQ process, the HARQ process should send the next TB. Otherwise, if a negative acknowledgement (NACK) to the data is received in this HARQ process, the TB is retransmitted.

HARQ should be based on incremental redundancy (Incremental Redundancy ₀ should note that chase merging is a special case of incremental redundancy and therefore can be supported without any doubt.

 In layer 1, the HARQ acknowledge bit is received from the MAC. Each positive acknowledgment (ACK) is encoded as a binary "0", and each negative acknowledgment "NACK" is encoded as a binary "1".

 In order to improve the quality of the above HARQ, many advanced HARQ technologies have been proposed in the IEEE.16m standardization discussion. Most of them require that when the retransmission is required, the receiver feeds back additional information to improve the quality or validity of the retransmission. Below is an example of the additional feedback information presented.

 Retransmission information length: In some scenarios, only a portion of the original transmitted information is severely corrupted, and the remaining information is received with satisfactory quality. In this case, spectral efficiency can be significantly improved by retransmitting part of the original information instead of all of the original information. Therefore, additional feedback must tell the BS which part of the information needs to be retransmitted.

Interleaving pattern for retransmission: In order to better utilize the frequency/time diversity of the channel, the retransmitted symbol bits may be transmitted in an order different from the order used in the previous transmission. This means you can use no The same interleaving pattern, which may be fixed in advance or selected by the MS from the pre-defined set of interleaving patterns according to the current channel conditions, and fed back to the BS along with the NACK signal.

 FEC block index: In some cases, several FEC blocks share the same CRC portion to reduce the load. When an error is detected, it is likely that not all FEC blocks but only some of them have errors. In this case, it is more efficient to retransmit only the FEC blocks that have errors, not all FEC blocks.

 Codebook Index: When the system uses codebook-based precoding MIMO processing, the channel conditions for retransmission are usually different from the channel conditions in the original/previous transmission. Therefore, the optimal precoding matrix for retransmission is also likely to be different from the optimal precoding matrix for original/previous transmission. Based on the current channel conditions and the previously received signals, the MS can reselect the precoding matrix to optimize the retransmission performance and feed back the updated precoding matrix index along with the NACK signal to the BS to improve the quality of the retransmission.

 From the above discussion, we can see that in order to improve the quality and efficiency of retransmissions, it is expected that additional information will be sent with "NACK". There is currently no technical solution for how to send this additional information. Summary of the invention

 In order to solve the above problems, embodiments of the present invention propose a system, a transmitter, a receiver, and a method thereof for retransmission.

 According to an aspect of an embodiment of the present invention, a method for requesting retransmission is provided, comprising the steps of: receiving a signal from a transmitter and determining whether retransmission is required, and feeding back in the main feedback channel whether a transmitter is required to perform retransmission. Instructing information; and if retransmission is required, feeding back retransmission enhancement information in a second feedback channel associated with the primary feedback channel, the retransmission enhancement information being a reception quality or transmission validity of the signal for retransmission of the levee Information.

 According to another aspect of an embodiment of the present invention, a retransmission method is provided, comprising the steps of: receiving a feedback signal in a primary feedback channel and a second feedback channel associated with the primary feedback channel; if found in primary feedback The channel carries a message that requires retransmission and carries retransmission enhancement information in a second feedback channel associated with the primary feedback channel, and performs retransmission according to the retransmission enhancement information carried in the second feedback channel, where The retransmission enhancement information is information for improving reception quality or transmission validity of a signal to be retransmitted.

According to another aspect of an embodiment of the present invention, a transmitter is provided, comprising: a receiving control unit, configured to receive a feedback signal in a second feedback channel associated with a primary feedback channel and a primary feedback channel, if found Carrying a message requesting retransmission in the primary feedback channel and in association with the primary feedback channel The retransmission enhancement information is carried in the second feedback channel, and the retransmission enhancement information is used to improve the reception quality or transmission of the retransmitted signal according to the retransmission enhancement information carried in the second feedback channel. Information of validity; a retransmission unit, used to retransmit according to the indication.

 According to another aspect of an embodiment of the present invention, a receiver is provided, including: a transmission control unit, configured to receive a signal from a transmitter and determine whether retransmission is required, and indicate whether feedback is required in a primary feedback channel. Retransmitted indication information; and if retransmission is required, indicating feedback of retransmission enhancement information in a second feedback channel associated with the primary feedback channel, the retransmission enhancement information being used to improve reception quality of the retransmitted signal Or transmission of validity information; feedback unit: used to feedback according to the indication.

 In accordance with another aspect of an embodiment of the present invention, a system for retransmission is provided, including the above transmitter and the above receiver.

 The existing HARQ feedback channel structure cannot support advanced HARQ techniques to require additional information from the MS to improve the quality/efficiency of retransmissions. The technical solution of the present invention solves this problem by introducing a hierarchical structure of a HARQ feedback channel and a second HARQ feedback channel based on a contention mechanism. This solution not only provides a solution that supports advanced HARQ technology, but also minimizes potential loads. Since multiple primary HARQ feedback channels share a second HARQ feedback channel in a competitive manner, the additional feedback load can be effectively reduced. By carefully selecting the number of primary HARQ feedback channels sharing a second HARQ feedback channel, the collision probability can be effectively controlled and the efficiency of the second HARQ feedback channel can be maximized. DRAWINGS

 The advantages of the present invention will become readily apparent from the following description in conjunction with the drawings in which:

 Figure 1 is a schematic diagram showing the results of LTE reception simulation;

 2 is a schematic structural diagram of a system according to an embodiment of the present invention;

 3 is a schematic structural diagram of a transmitter according to an embodiment of the present invention;

 4 is a schematic structural diagram of a receiver according to an embodiment of the present invention;

 FIG. 5 is a flowchart of request retransmission according to an embodiment of the present invention; FIG.

 6 is a schematic diagram showing a hierarchical retransmission feedback channel structure according to an embodiment of the present invention; FIG. 7 is a schematic diagram of collision probability and resource usage for a transmission decoding failure rate = 0.1 according to an embodiment of the present invention;

8 is a collision probability and resource usage for a transmission decoding failure rate = 0.2 according to an embodiment of the present invention. Schematic diagram of the rate;

 9 is a flow chart of an encoding step in accordance with an embodiment of the present invention;

 FIG. 10 is a schematic diagram showing an example of changing a retransmission format based on a code block error according to an embodiment of the present invention; FIG.

 11 is a flow chart of performing retransmission according to an embodiment of the present invention;

 FIG. 12 is a schematic diagram showing the gain of the HARQ and the change retransmission format proposed by the embodiment of the present invention. detailed description

 Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

 As can be seen from the analysis of the prior art, in order to improve the quality and efficiency of the retransmission, some additional information needs to be sent along with the "NACK". A second HARQ feedback channel can be provided in an embodiment of the invention. Since additional retransmission enhancement information is required only when feedback "NACK" is required, it is difficult to assign a second HARQ feedback channel to each user in advance. One possible solution is to assign a second HARQ feedback channel to each user. However, since in a real system, the probability of decoding failure is approximately 10% to 20%, if a second HARQ feedback channel is allocated for each user, more than 80% of the resources are wasted. Therefore, preferably, embodiments of the present invention propose a second HARQ feedback channel based on a contention mechanism to solve this problem.

 The basic idea of an embodiment of the present invention is to define a hierarchical structure of a HARQ feedback channel: The primary HARQ feedback channel is the same as a conventional HARQ feedback channel, and is used to transmit "ACK" and "NACK" indicators, and the second HARQ feedback channel is feedback" The transmission of NACK" is to send additional information to improve the quality/efficiency of the retransmission. The primary HARQ channel is for transmission-specific, that is, one HARQ feedback channel is allocated for each HARQ-enabled transmission. The second HARQ feedback channel is allocated to multiple primary HARQ feedback channel sharing, and the user who needs to retransmit can feed back the retransmission enhancement information on the second HARQ feedback channel. A plurality of users who need to feed back information on the same second HARQ feedback channel need to compete.

 The following describes the uplink channel of the 3G LTE system as an example.

In 3G LTE, the size of the transport block (TB) is larger than the TB in UMTS. Of the defined TBs, approximately 64.5% are segmented into multiple code blocks (CBs). TB and its CB are protected with the same CRC. In a TB, only a few CB decodings may fail, but the entire TB will be retransmitted, resulting in wasted resources. The simulation results in the parameters shown in Table 1 show that when the first transmission error rate is about 5% to 20%, it is wasted. The ratio is about 15% to 20%.

 Table 1 Simulation parameters

 When using 2/3 Turbo code, 16QAM and ΟΜΗζ, the transport block with the CRC sequence is 14688, which is segmented into 3 code blocks.

 Figure 1 shows the results of the simulation. As can be seen from Figure 1, when the first transmission error rate is about 10%, the block correctness rate reaches 20%. When the bandwidth is widened and the transport block becomes larger, the correct rate of the code block becomes larger, and the waste caused by retransmitting the transport block is also greater.

 In order to solve this problem, embodiments of the present invention propose base stations, mobile terminals, systems and methods for retransmission.

 Embodiments of the present invention propose a system for retransmission, as shown in Figure 2, which includes a transmitter and a receiver as described below.

Embodiments of the present invention also propose a transmitter for retransmission. As shown in FIG. 3, the transmitter includes: The receiving control unit 310 is configured to receive a feedback signal in the second feedback channel and the second feedback channel associated with the primary feedback channel, if it is found that the primary feedback channel carries the indication information requesting retransmission and is in the primary feedback channel The associated second feedback channel carries retransmission enhancement information, and indicates that retransmission is performed according to the retransmission enhancement information carried in the second feedback channel, where the retransmission enhancement information is used to improve the reception quality or transmission of the retransmitted signal. Information of validity; a retransmission unit 320, configured to perform retransmission according to the indication.

 The receiving control unit 310 includes: a despreading module 312, configured to despread the received signal in the third feedback channel by using a spreading sequence associated with the primary feedback channel; and a measuring module 314, configured to measure the despreading module The SINR of the despread signal is 312. The determining module 316 is configured to, when determining that the SINR measured by the measurement module 314 is greater than a predetermined threshold, instructing to use the despreading module 312 to despread the obtained retransmission enhanced information for retransmission.

 The transmitter may further include a channel association unit 330 for pre-setting a correspondence between the primary feedback channel and the second feedback channel for use by the despreading module 312.

 The transmitter may further include a spreading sequence processing unit 340 for predetermining the set of spreading sequences, assigning one spreading sequence of the set of spreading sequences to each primary HARQ feedback channel for use by the despreading module 312. An embodiment of the present invention proposes a receiver for retransmission, as shown in FIG. 4, the receiver includes a transmission control unit 410 for receiving a signal from a transmitter and determining whether retransmission is required, and in the main feedback The feedback in the channel requires the transmitter to perform retransmission indication information; if retransmission is required, the retransmission enhancement information is fed back in the second feedback channel associated with the primary feedback channel, where the retransmission enhancement information is used to improve the retransmission Information on the reception quality or transmission validity of the signal; a feedback unit 420 for performing feedback according to the indication.

 The receiver further includes a spreading unit 430 for spreading the retransmission enhancement information using a spreading sequence associated with the primary feedback channel; the transmission control unit 410 indicating a second feedback channel associated with the primary feedback channel The retransmission enhanced information is carried in the spread spectrum.

 The receiver may further include a spreading sequence processing unit 440 for predetermining the set of spreading sequences, and assigning one spreading sequence of the set of spreading sequences to each primary HARQ feedback channel for use by the spreading unit 430. The receiver may also include a channel association unit 450 for presetting the correspondence between the primary feedback channel and the second feedback channel for use by the transmission control unit 410. When the mobile terminal is used as a receiver, the transmission control unit 410 and the spreading unit 430 can also receive information about the spreading sequence and the correspondence between the primary feedback channel and the second feedback channel from the base station as the transmitter.

Although the transmitter and receiver of the embodiments of the present invention have been described above in the form of separate functional modules, each of the components shown in Figures 3 and 4 can be implemented in multiple devices in practical applications, showing many Group The device can also be integrated in a chip or a device in practical applications. The transmitter and receiver may also include any unit and device for other purposes.

 The method provided by the embodiment of the present invention will be described below based on the above transmitter and receiver. FIG. 5 shows a flow chart of requesting retransmission in an embodiment of the present invention. As shown in FIG. 5, in step 510, the channel association unit 330 of the transmitter or the channel association unit 450 of the receiver sets a correspondence between the primary feedback channel and the second feedback channel.

 Fig. 6 shows a hierarchical structure of a HARQ feedback channel in an embodiment of the present invention. As shown in FIG. 6, a plurality of primary HARQ feedback channels share a common second HARQ feedback channel. When one or more transmission decodings associated with these primary HARQ feedback channels fail, the corresponding user competes to use the second HARQ feedback channel to transmit additional information to the base station to improve the quality and efficiency of the retransmission. In particular, there are three cases - if only one decoding failure occurs, the corresponding user can successfully transmit the retransmission enhancement information on the second HARQ feedback channel. The BS decodes the message on the second HARQ feedback channel decoding and uses the message to design a retransmission format, i.e., a precoding matrix of the failed message, retransmission information, an interleaving pattern used, and the like.

 If more than one decoding failure occurs, a collision occurs when more than one user will simultaneously transmit on the second HARQ feedback channel. In this case, the BS may rely on different spreading sequences on the second HARQ feedback channel to distinguish retransmission enhancement information from different users, and use the despread SINR to determine whether the detection is correct. If the despread SINR is above a predetermined threshold, the detection is considered correct and the information is used for retransmission. If the despread SINR is below the predetermined threshold, then the detection error is considered and the retransmission is degraded to the conventional case without any retransmission enhancement information. :

 If all transmissions are successfully decoded, no information is passed on the second HARQ feedback channel.

 A key design consideration for embodiments of the present invention is to balance the trade-offs between collision probabilities. The probability of collision depends on the number of primary HARQ feedback channels (N) sharing the same second HARQ feedback channel and the decoding failure probability (j3⁄4) of each transmission. By reducing the number of primary HARQ feedback channels sharing the same second HARQ feedback channel, the collision probability (^) can be effectively reduced, but the utilization rate ff) of the second HARQ feedback channel is also reduced. We will then analyze the trade-off between conflict probability and resource usage.

 It is assumed that N primary HARQ feedback channels share a second HARQ feedback channel. Assume that the probability of decoding failure for each transmission is ^. The probability of collision can be calculated as:

P _c =\-Np _e (\-p _e ) ^N - ^l -(lp _e ) ^N The resource usage rate can be expressed as the probability of successful delivery on the second HARQ feedback channel, 艮卩:

Eff=Np _e {\-p _e ) ^N - ^]

 The goal of the trade-off is to give the appropriate value N for the given value; to maximize e# while keeping /i 可接受 acceptable value.

Figures 7 and 8 show the relationship between ^, ^ and N for the case of /7 _e = 0.1 and 0.2, respectively. As shown in Fig. 7 and Fig. 8, it can be seen that for N, the efficiency has a global maximum point, and _Pe increases as N increases, which is reasonable because when more primary HARQ feedback channels share a common number When two HARQ feedback channels are used, the collision probability will increase. The appropriate value N can be selected according to these figures for different purposes to maximize efficiency φ below a predetermined threshold. The assumed collision probability should be less than 10%. For the purpose, you can choose Ν=5; for /? _e =0.2, you can choose N=3.

 In step 512, the sequence processing unit 340 of the transmitter or the spreading sequence processing unit 440 of the receiver predetermines a set of spreading sequences (orthogonal or semi-orthogonal sequences).

 In addition, the spreading sequence processing unit 340 of the transmitter or the spreading sequence processing unit 440 of the receiver allocates one spreading sequence in the set of spreading sequences for each primary HARQ feedback channel. Different primary or secondary HARQ feedback channels may be assigned different or identical based on the number N of primary HARQ feedback channels corresponding to the same second HARQ feedback channel determined in step 610, and the size of the spreading sequence group determined in step 620. Spreading sequence. For example, if the number N of the primary HARQ feedback channels is greater than the size of the spreading sequence group, first, different spreading sequences are allocated to the primary HARQ feedback channel, and after the spreading sequence is allocated, the allocated spreading sequence groups are repeatedly used. It is assigned to the remaining primary HARQ feedback channel.

 In step 514, the correspondence between the set of spreading sequences and its primary HARQ feedback channel is shared between the BS and the MS.

 In a practical application, preferably, steps 510 to 514 are performed in the base station, and at this time, the base station may be a transmitter or a receiver. At this time, the mobile terminal can receive information about the spreading sequence and the correspondence between the primary feedback channel and the second feedback channel from the base station. At the same time, those skilled in the art will appreciate that the information determined by the above steps can be used in multiple retransmissions, so it is not necessary to repeat this step before each retransmission.

For convenience of description, it is assumed in the following description that the transmitter is a base station and the receiver is a mobile terminal. First, the method of requesting retransmission will be explained. In step 516, if the mobile terminal cannot successfully decode the received transmission, indicating that the transmission is in error, the feedback unit 420 of the receiver feeds back a "NACK" message in the primary HARQ feedback channel, and the spreading unit 430 of the mobile terminal is used as the primary The spreading sequence assigned by the HARQ feedback channel spreads the retransmission enhancement information.

 In step 518, feedback unit 420 carries the spread information in a second HARQ feedback channel associated with the primary HARQ feedback channel for transmission.

 In LTE, a CRC sequence is attached to each code block. Figure 9 shows the processing structure for the DL-SCH, PCH and MCH transport channels. At each transmission time interval (TTI) data arrives at the coding unit in the form of a maximum of one transmission block. As shown in Fig. 9, the following coding steps can be determined:

 Step 910: Add the CRC to the transport block

 Step 920: Perform code block segmentation on the transmission segment and CRC attachment of the code block.

 Step 930: Channel coding the code block that has code block segmentation and code block CRC attachment

 Step 940: Perform rate matching

 Step 950: Code block concatenation

 Error detection is provided to the transport block by cyclic redundancy check (CRC). The entire transport block is used to calculate the CRC check bits.

 The input bit sequence of the code block segmentation in step 920 is represented as ^H^'^, where B>0. If B is greater than the maximum code block size Z, segmentation of the input bit sequence is performed, and an additional L=24 CRC sequence is attached to each code block. The maximum code block size is: Z=6144.

 The proposed HARQ scheme pays more attention to the details of the TB data. Although the transmission is always based on TB, the feedback and retransmission are different from transport block based HARQ.

 In this embodiment, there are two indicators: a primary indicator and a second indicator, where the primary indicator is a binary for carrying an ACK or NACK transmitted on the primary HARQ feedback channel, and the second indicator is a code A bitmap sequence of the block for carrying retransmission enhancement information transmitted in the second HARQ feedback channel. For example, the maximum TB without special multiplexing is 73712. If the maximum code block size is: Z = 6144, then the corresponding number of code blocks is 12. A 4-bit CRC is appended to the HARQ indicator (; HI) (second indicator) as shown in Table 2.

如果传输块被映射到两层空间复用， 该传输块可以倍增。一种方法是使指示符 增大到 24比特， 但可能造成过载。 另一种方法是使用 12比特， 以 1个比特指示两 个码块。 Table 2 Codewords in HARQ-based code blocks

If the transport block is mapped to two layers of spatial multiplexing, the transport block can be multiplied. One way is to increase the indicator to 24 bits, but this can cause an overload. Another method is to use 12 bits to indicate two code blocks with 1 bit.

 The submitted HARQ scheme should be adaptive based on the transmission properties (i.e., transport blocks that only include incorrect code blocks).

 Adaptive means that the transmitter can change some or all of the attributes used in each retransmission (e.g., due to changes in the transport block format) compared to the initial transmission. Therefore, the associated control information needs to be sent along with the retransmission. The changes considered include:

 First: code rate

 Second: modulation

 Third: resource unit allocation

 Using the proposed HARQ scheme, the HARQ process is similar to the previous one. It includes IR, N-channel stop-and-wait protocol, synchronous or asynchronous, adaptive and soft cache management. Although the feedback HARQ indicator can occupy more bits, retransmission can apply a lower code rate for higher reception performance.

 If the HARQ indicator CRC check is a failure, the entire TB is retransmitted and does not affect the HARQ-process. Figure 10 illustrates one embodiment of changing the retransmission format based on code block errors. As shown in Fig. 10, the initial transmission applies 2/3 Turbo code and 16 QAM, and divides one transport block into 3 code blocks. If the receiver verifies that two code blocks are in error and the other is correct, feedback indicator 110 (or 011, 101). The transmitter should retransmit the first two code blocks (or the last two code blocks, or the first and third code blocks). In order to fill the entire transport block, 4/9 Turbo code rate is applied and 16QAM modulation is maintained.

 If the receiver verifies that only one code block is in error and the remaining two are correct, the feedback indicator 100 (or 010, 001). The transmitter understands that the first code block (or the second last code block, or the third code block) should be retransmitted. In order to fill the entire transport block, 4/9 Turbo code rate should be maintained and QPSK modulation applied.

 With the above technical solution, while achieving higher retransmission quality and efficiency, the load on the system is not greatly affected. A 1-bit primary indicator is used to indicate whether the transport block is erroneous ACK/NACK, and a second indicator is used to indicate a bitmap error block bitmap. If a positive acknowledgment (ACK) is encoded in the primary indicator, there is no need to The second indicator is encoded. Taking the second indicator as 16. For example, assuming that the probability of the first transmission error is 10% to 20%, the total load of the feedback is:

The first transmission error probability is 10%: 1 bit * 90% + ( 1+16) bits * 10% = 2.6 bits The probability of the first transmission error is 20%: 1 bit * 80% + (1+16) bits * 20% = 4.2 bits It can be seen that the actual load is less than 5 bits. In addition, the transport block size determines the second indicator size. If the size of the second indicator is limited according to the transport block size, the actual load will be smaller.

 Next, a method of performing retransmission will be described. Figure 11 is a flow diagram of retransmission in accordance with an embodiment of the present invention. As shown in Figure 11:

 In step 1110, when the "NACK" message is carried in the primary HARQ feedback channel, the despreading module 312 in the receiving control unit 310 of the base station uses the spreading sequence associated with the primary HARQ feedback channel in the second HARQ feedback channel. The received signal is despread.

 In step 1120, the measurement module 314 of the base station measures the SINR of the despread signal.

 In step 1130, the decision module 316 of the base station determines whether the SINR measured by the measurement module 314 is greater than a predetermined threshold. If the detection of the second HARQ feedback channel is considered successful, if greater than the predetermined threshold, the retransmission unit 320 of the base station in step 1150 utilizes The despreading module 312 despreads the retransmission enhanced information for retransmission; otherwise, it is considered that the detection of the second HARQ feedback channel fails, the obtained retransmission enhancement information is discarded in step 1140, and the retransmission unit 320 performs the conventional HARQ retransmission.

 Fig. 12 is a diagram showing the gain of the HARQ and variation retransmission format proposed by the embodiment of the present invention. As shown in Fig. 12, according to the code block error, the proposed HARQ scheme using the change retransmission format can obtain the gain of ldB as compared with the conventional IR HARQ scheme.

 The above description of the method for retransmission is based on the fact that the base station is a transmitter and the mobile terminal is a receiver (i.e., downlink), however, those skilled in the art can easily infer that the above system, transmitter, receiver And methods can also be used where the base station is the receiver and the mobile terminal is the transmitter (ie, the uplink).

 In the above embodiment, a second HARQ feedback channel is used for multiple primary HARQ feedback channels. In practical applications, more than one second HARQ feedback channel may also be used. For example, in the case where the radio environment is relatively harsh, the number of second HARQ feedback channels can be increased to reduce the probability of collision.

The technical solutions provided by the embodiments of the present invention are equally applicable to other high-speed wireless communication systems, such as LTE-Advanced and WiMAX IEEE 802.16 systems. Similarly, the content included in the retransmission enhancement information may also be different according to different systems, for example, the retransmission enhancement information may further include an interlace pattern, a FEC index, and/or a codebook index for retransmission. It is not limited to the length of the retransmission information used in the above embodiment. Those skilled in the art will readily recognize that the different steps of the above methods can be implemented by a programmed computer. Herein, some embodiments also include a machine readable or computer readable program storage device (eg, a digital data storage medium) and encoding machine executable or computer executable program instructions, wherein the instructions perform some of the above methods or All steps. For example, the program storage device can be a digital memory, a magnetic storage medium (such as a magnetic disk and magnetic tape), a hardware or an optically readable digital data storage medium. Embodiments also include a programming computer that performs the steps of the above method.

 The description and drawings merely illustrate the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various structures, which are not specifically described or illustrated herein, but are intended to be within the spirit and scope of the invention. In addition, all of the examples mentioned herein are explicitly used primarily for teaching purposes to assist the reader in understanding the principles of the present invention and the concepts promoted by the inventors, and should be construed as not to the specific examples. And conditional restrictions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as the specific examples thereof,

 The above description is only used to implement the embodiments of the present invention, and those skilled in the art should understand that any modifications or partial substitutions without departing from the scope of the present invention should fall within the scope defined by the claims of the present invention. The scope of the invention should be determined by the scope of the claims.

Claims

Rights request 1. A method for requesting retransmission, comprising:  Receiving a signal from the transmitter and determining whether retransmission is required, and feeding back, in the main feedback channel, an indication of whether the transmitter is required to perform retransmission;  If retransmission is required, retransmission enhancement information is fed back in a second feedback channel associated with the primary feedback channel, the retransmission enhancement information being information for improving reception quality or transmission efficiency of the retransmitted signal.  2. The method according to claim 1, wherein the carrying the retransmission enhancement information in the second feedback channel associated with the primary feedback channel comprises:  The retransmission enhancement information is spread using a spreading sequence associated with the primary feedback channel; the spread retransmission enhancement information is carried in the second feedback channel for transmission.  3. The method according to claim 2, wherein a plurality of code blocks constitute a transport block for transmission, and a bitmap of the code block is carried in the retransmission enhancement information transmitted in the second feedback channel. The sequence is to inform the transmitter which code blocks in the transport block need to be retransmitted.  4. The method of claim 3, further comprising  Establishing a correspondence between the primary feedback channel and the second feedback channel.  5. The method according to claim 4, wherein the establishing a correspondence between the primary feedback channel and the second feedback channel comprises selecting a plurality of primary feedback channels to correspond to at least one second feedback channel:  Transmitting the retransmitted enhanced information to be transmitted in the second feedback channel includes transmitting the spread retransmission enhanced information in a contention manner at least one second associated with the plurality of primary feedback channels Sended in the feedback channel.  6. The method according to any one of claims 1 to 5, further comprising  Predetermining a set of spreading sequences including the spreading sequence;  Allocating a spreading sequence in the set of spreading sequences for each primary feedback channel;  The set of spreading sequences and their correspondence to the primary feedback channel are shared between the transmitter and the receiver.  7. The method according to claim 6, wherein different or the same expansion is allocated for different main feedback channels based on the size of the set of spreading sequences and the number of primary feedback channels corresponding to the second feedback channel. Frequency sequence. 8. The method according to claim 7, wherein the spreading sequence is a semi-orthogonal sequence or an orthogonal sequence. 9. A retransmission method, including the steps:  Receiving a primary feedback channel and a feedback signal in a second feedback channel associated with the primary feedback channel; if found in the primary feedback channel carrying indication information requiring retransmission and in a second associated with the primary feedback channel The retransmission enhancement information is carried in the feedback channel, and is retransmitted according to the retransmission enhancement information carried in the second feedback channel, where the retransmission enhancement information is used to improve the reception quality or transmission of the retransmitted signal. Information on effectiveness.  10. The method according to claim 9, wherein  The retransmitting according to the retransmission enhancement information carried in the second feedback channel includes:  Despreading the signal received in the second feedback channel using a spreading sequence associated with the primary feedback channel;  Measuring a signal to interference and noise ratio SINR of the despread signal;  The SINR is compared with a predetermined threshold, and if the SINR is greater than the threshold, the retransmission enhanced information obtained by despreading is used for retransmission. If the NR is less than the threshold, the received signal in the second feedback channel is discarded, and retransmission is performed in a manner that does not retransmit the enhanced information.  The method according to claim 10, wherein the plurality of code blocks constitute a transport block for transmission, and retransmission using the retransmission enhanced information obtained by despreading comprises retrieving from the retransmission enhanced information. The bitmap sequence of the code block knows which code blocks in the transport block need to be retransmitted and retransmits accordingly.  12. The method of claim 11 further comprising  Establishing a correspondence between the primary feedback channel and the second feedback channel.  13. The method according to claim 12, wherein the establishing a correspondence between the primary feedback channel and the second feedback channel comprises selecting a plurality of primary feedback channels to correspond to at least one second feedback channel.  14. The method of any of claims 9 to 13, further comprising  Predetermining a set of spreading sequences including the spreading sequence;  Assigning one spreading sequence in the set of spreading sequences to each primary feedback channel; sharing the set of spreading sequences and its correspondence with the primary feedback channel between the transmitter and the receiver.  15. The method according to claim 14, wherein different or identical spreading sequences are assigned to different primary feedback channels based on a size of the sequence group and a number of primary feedback channels corresponding to the second feedback channel. . 16. The method of claim 15, wherein the sequence is a semi-orthogonal sequence or an orthogonal sequence. 17. A transmitter comprising:  a receiving control unit, configured to receive a primary feedback channel and a feedback signal in a second feedback channel associated with the primary feedback channel, if found in the primary feedback channel, carrying indication information requiring retransmission and The retransmission enhancement information is carried in the second feedback channel associated with the feedback channel, and the retransmission enhancement information is used to perform retransmission according to the retransmission enhancement information carried in the second feedback channel, where the retransmission enhancement information is used to improve retransmission. Information on the reception quality or transmission validity of the signal; '  And a retransmission unit, configured to perform retransmission according to the indication.  18. The transmitter of claim 17, the receiving control unit comprising: a despreading module, configured to despread a signal received in a second feedback channel using a spreading sequence associated with a primary feedback channel;  a measuring module, configured to measure a signal to interference and noise ratio SINR of the despread signal of the despreading module;  a determining module, configured to determine whether the SINR measured by the measurement module is greater than a predetermined threshold, and when the SINR is greater than a predetermined threshold, indicating that the retransmission enhanced information obtained by despreading by the despreading module is retransmitted, Otherwise, the signal received in the second feedback channel is discarded, and the retransmission is performed in a manner that does not retransmit the enhanced information.  19. The transmitter of claim 18, further comprising:  And a channel association unit, configured to preset a correspondence between the primary feedback channel and the second feedback channel, for use by the despreading module.  20. The transmitter of claim 19, further comprising:  The spreading sequence processing unit is configured to predetermine the spreading sequence group, and allocate one spreading sequence in the spreading sequence group for each primary HARQ feedback channel for use by the despreading module.  21. A receiver comprising:  And a sending control unit, configured to receive a signal from the transmitter and determine whether retransmission is needed, and feed back, in the main feedback channel, whether the transmitter needs to perform retransmission indication information. If retransmission is required, retransmission enhancement information is fed back in a second feedback channel associated with the primary feedback channel, the retransmission enhancement information being information for improving reception quality or transmission efficiency of the retransmitted signal;  Feedback unit: Used to feedback according to the indication. ,  22. The receiver of claim 21, further comprising: a spreading unit, configured to use the spreading sequence associated with the primary feedback channel to enhance the retransmission information Performing spread spectrum;  The transmission control unit instructs to feed back the spread retransmission enhancement information in a second feedback channel associated with the primary feedback channel.  23. The receiver of claim 22, further comprising  And a channel association unit, configured to preset a correspondence between the primary feedback channel and the second feedback channel for use by the sending control unit.  24. The receiver of claim 23, further comprising:  The spreading sequence processing unit is configured to predetermine the spreading sequence group, and allocate one spreading sequence in the spreading sequence group for each primary HARQ feedback channel for use by the spreading unit.  A system for retransmission, comprising a transmitter according to any one of claims 17 to 20 and a receiver according to any one of claims 21 to 24.