WO2018126442A1 - 一种混合自动重传请求的方法和装置 - Google Patents

一种混合自动重传请求的方法和装置 Download PDF

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WO2018126442A1
WO2018126442A1 PCT/CN2017/070435 CN2017070435W WO2018126442A1 WO 2018126442 A1 WO2018126442 A1 WO 2018126442A1 CN 2017070435 W CN2017070435 W CN 2017070435W WO 2018126442 A1 WO2018126442 A1 WO 2018126442A1
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information
retransmission
check matrix
initial transmission
mapped
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PCT/CN2017/070435
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English (en)
French (fr)
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刘晓健
魏岳军
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华为技术有限公司
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Priority to PCT/CN2017/070435 priority Critical patent/WO2018126442A1/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

Definitions

  • the present invention relates to the field of mobile communications, and in particular, to a method and apparatus for hybrid automatic repeat request.
  • FEC Forward Error Correction
  • ARQ Automatic Repeat ReQuest
  • HARQ Hybrid Automatic Repeat ReQuest
  • Hybrid automatic repeat request generally has two implementation schemes, namely Chase Combining (CC) and incremental redundancy (IR).
  • CC Chase Combining
  • IR incremental redundancy
  • the principle of Chase merging is that the data packet sent by the sender to the receiver is the same as the data packet at the time of the initial transmission, and the receiver combines the originally transmitted code packet with the retransmitted code packet and then decodes it.
  • the performance gain of Chase merge is not high, lower than IR merge.
  • the principle of IR merging is that the data sent by the transmitting end to the receiving end during retransmission is redundant information obtained based on the data encoding at the time of initial transmission, and the receiving end receives the redundant information transmitted by the retransmission, and then transmits it to the initial transmission. Data splicing is jointly decoded using a lower code rate check matrix to recover the data.
  • the performance gain of IR combining is higher than that of Chase, the decoding complexity of the receiving end is high, which easily leads to system delay.
  • This paper describes a method and apparatus for hybrid automatic repeat request for LDPC codes, which can combine Chase combining and IR combining, and can retransmit information that plays an important role in decoding, thereby improving the weight.
  • the performance gain is reduced, which reduces the complexity of retransmission information decoding and reduces system delay.
  • an embodiment of the present invention provides a hybrid automatic retransmission method for an LDPC code, where the method includes: transmitting retransmission information, where the retransmission information is composed of first information and incremental redundancy information;
  • the first information includes one or more pieces of information mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; wherein the initial transmission check matrix
  • the information corresponding to a particular column is more important than the information corresponding to other columns in the initial check matrix.
  • the information with high importance for retransmission can be retransmitted in combination with the incremental redundancy information, so that the advantages of Chase combining and IR combining can be combined, and the performance gain of retransmission is improved, and the performance is reduced.
  • the complexity of retransmitting information decoding reduces system delay.
  • the method before the sending the retransmission information, the method further includes: performing bit sequence rearrangement or interleaving on the retransmission information, so as to enable The first information is mapped to a reliable bit.
  • the retransmission information is subjected to bit sequence rearrangement or interleaving so that information having higher importance for retransmission can be mapped onto the reliable bits, thereby further providing performance gain of retransmission.
  • the method before the sending the retransmission information, the method further includes: performing bit sequence rearrangement or interleaving on the first information, so as to enable Information that is mapped to unreliable bits at the time of initial transmission in the first information is mapped to a reliable bit.
  • bit sequence rearrangement or interleaving is performed on the first information, so that the first information is initially Information that is mapped to unreliable bits is mapped to reliable bits, further providing performance gains for retransmissions.
  • the method further includes: extending an initial transmission check matrix according to a code length of the incremental redundancy information, to obtain a retransmission check matrix.
  • the retransmission check matrix can be obtained by extending the initial transmission check matrix according to the code length of the incremental redundancy information, thereby reducing the complexity of retransmission information decoding and reducing system delay.
  • the embodiment of the present invention further provides another hybrid automatic retransmission method for an LDPC code, where the method includes: receiving retransmission information, where the retransmission information includes first information and incremental redundancy information.
  • the first information includes one or more of information that is mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; wherein the first pass school
  • the information corresponding to the specific column in the matrix is more important than the information corresponding to the other columns in the initial check matrix.
  • an embodiment of the present invention provides a hybrid automatic retransmission apparatus for an LDPC code, where the apparatus includes: a sending unit, configured to send retransmission information, where the retransmission information is performed by the first information and the increment Redundant information consisting of: the first information includes information mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and one or more of puncturing information; wherein The information corresponding to the specific column in the initial check matrix is more important than the information corresponding to the other columns in the initial check matrix.
  • the embodiment of the present invention further provides another hybrid automatic retransmission apparatus for an LDPC code, where the apparatus includes: a receiving unit, configured to receive retransmission information, where the retransmission information is performed by the first information and Incremental redundancy information; the first information includes one or more of information that is mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; The information corresponding to the specific column in the initial transmission check matrix is higher than the information corresponding to the other columns in the initial transmission check matrix.
  • an embodiment of the present invention provides a hybrid automatic retransmission communication apparatus for an LDPC code, where the communication apparatus includes: a radio frequency circuit, configured to send retransmission information, where the retransmission information is performed by the first information and Incremental redundancy information; the first information includes mapping to unreliable bits at initial transmission Information, one or more of information corresponding to a specific column in the initial check matrix, and puncturing information; wherein information corresponding to a specific column in the initial check matrix is more important than the first pass school Check the information corresponding to other columns in the matrix.
  • an embodiment of the present invention provides a hybrid automatic retransmission communication apparatus for an LDPC code, where the communication apparatus includes: a radio frequency circuit, configured to receive retransmission information, where the retransmission information is performed by the first information and Incremental redundancy information; the first information includes one or more of information that is mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; The information corresponding to the specific column in the initial transmission check matrix is higher than the information corresponding to the other columns in the initial transmission check matrix.
  • the hybrid automatic retransmission method and device for LDPC code provided by the embodiment of the present invention can retransmit the information with high importance for retransmission decoding and the incremental redundancy information when performing retransmission, thereby
  • the retransmission performance gain can be improved, the complexity of retransmission information decoding is reduced, and the system delay is reduced.
  • FIG. 1 is a schematic diagram of a check matrix of an LDPC code according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a process of a transmitting end of a hybrid automatic retransmission method according to an embodiment of the present invention
  • FIG. 3 is a schematic diagram of a process of receiving a retransmission by using a hybrid automatic retransmission method according to an embodiment of the present invention
  • FIG. 4 is a schematic diagram of performance of a hybrid automatic retransmission method according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of performance of another hybrid automatic retransmission method according to an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of performance of another hybrid automatic retransmission method according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram of performance of another hybrid automatic retransmission method according to an embodiment of the present invention.
  • FIG. 8 is a schematic structural diagram of a hybrid automatic retransmission device according to an embodiment of the present invention.
  • FIG. 9 is a schematic structural diagram of another hybrid automatic retransmission device according to an embodiment of the present invention.
  • FIG. 10 is a schematic structural diagram of a hybrid automatic repeat communication device according to an embodiment of the present invention.
  • FIG. 11 is a schematic structural diagram of a hybrid automatic repeat communication device according to an embodiment of the present invention.
  • the transmitting device and the receiving device in the embodiments of the present application may be any one of the transmitting end device and the receiving end device that performs data transmission in a wireless manner.
  • the transmitting device and the receiving device may be any device having a wireless transceiving function, including but not limited to: a base station NodeB, an evolved base station eNodeB, a base station in a fifth generation (5G) communication system, and a future communication system.
  • the UE may also be referred to as a terminal terminal, a mobile station (MS), a mobile terminal (MT), or the like.
  • the UE may communicate with one or more core networks via a radio access network (RAN), or may access the distributed network in an ad hoc or unlicensed manner, and the UE may also access the wireless network through other means.
  • RAN radio access network
  • the UE can also directly perform wireless communication with other UEs, which is not limited by the embodiment of the present application.
  • the data transmission method provided by the embodiment of the present application can be applied to downlink data transmission, and can also be applied to uplink data transmission, and can also be applied to device to device (D2D) data transmission.
  • the sending device may be a base station, and the corresponding receiving device may be a UE.
  • the sending device may be a UE, and the corresponding receiving device may be a base station.
  • D2D data transmission the sending device may be a UE, and the corresponding receiving device may also be a UE.
  • the embodiment of the present application does not limit this.
  • the transmitting device and the receiving device in the embodiments of the present application may be deployed on land, including indoors or outdoors, handheld or on-board; or may be deployed on the water; or may be deployed on aircraft, balloons, and satellites in the air.
  • the UE in the embodiment of the present application may be a mobile phone or a mobile phone. Tablet computer, computer with wireless transceiver function, Virtual Reality (VR) terminal device, Augmented Reality (AR) terminal device, wireless terminal in industrial control, driverless ( Wireless terminal in self driving, wireless terminal in remote medical, wireless terminal in smart grid, wireless terminal in transportation safety, wireless in smart city Terminals, wireless terminals in smart homes, etc.
  • the embodiment of the present application does not limit the application scenario.
  • the retransmission data packet and the initial transmission data packet have the same decoding complexity; and the retransmitted data packet supports self-decoding, so that the data can be recovered even if the original transmission packet is lost.
  • the performance gain of Chase combining is only due to an increase in signal-to-noise ratio, so the gain is limited.
  • the device at the transmitting end when retransmitting, the device at the transmitting end reverses the bit sequence mapped to the symbol at the initial transmission, and then sends the sequence to the device at the receiving end.
  • the bit-to-noise ratio of the combined initial and retransmission tends to be averaged to improve performance gain; in addition, when retransmitting, different constellation mapping patterns can be used to average the degree of protection of 0 and 1 in the bit sequence.
  • the device at the transmitting end can encode all the bits of the initial transmission data and add redundant information to obtain incremental redundancy information of the initial transmission data, and transmit different redundant parity bits during retransmission;
  • the initial data may also be punctured.
  • the punctured bits are sent to the device at the receiving end; the device at the transmitting end may also perform retransmission in the above two manners.
  • the device at the receiving end combines the retransmitted data with the initial transmitted data, and uses a larger size check matrix decoding to recover the encoded information.
  • the IR combining can obtain the signal-to-noise ratio gain and the coding gain.
  • the retransmitted data packet does not support self-decoding, and the decoding parity check matrix after retransmission becomes larger, which increases the decoding complexity and system delay.
  • the embodiment of the invention provides a hybrid automatic retransmission method, which can be applied to a check matrix.
  • a nested Raptor-like LDPC code the LDPC code supports incremental redundancy retransmission; the check matrix of the LDPC code has a high code rate core, as shown in Figure 1, and can be extended during retransmission A low code rate retransmission check matrix is obtained.
  • the device at the transmitting end can select part of the initial transmission information, and generate incremental redundancy information according to the retransmission check matrix, and then combine the selected partial initial transmission information and incremental redundancy information, after mapping and modulation. The device sent to the receiving end.
  • the hybrid automatic retransmission method provided by the embodiment of the present invention combines the advantages of chase combining and IR combining, can achieve higher signal to noise ratio gain and coding gain, and reduces the complexity of retransmission information decoding, and reduces system time. Delay.
  • the corresponding portion when the initial transmission is performed, the corresponding portion may be intercepted from the illustrated check matrix according to the code length and the code rate given by the system as an initial transmission check matrix, and the information to be transmitted is encoded to obtain the initial transmission.
  • the information is mapped, modulated, and transmitted.
  • the Raptor-like LDPC code is taken as an example; it can be assumed that the code length of the initial transmission is N, and the code rate is R; N columns and Ns can be intercepted from the parity check matrix corresponding to the Raptor-like LDPC code. -R), specifically, N columns, N (1-R) rows may be intercepted from the upper left corner of the check matrix as an initial pass check matrix; then the information to be transmitted is encoded according to the initial check matrix In order to obtain the initial transmission information, the initial transmission information is mapped, modulated, and transmitted.
  • a hybrid automatic retransmission method for an LDPC code provided by an embodiment of the present invention is specifically introduced.
  • the LDPC code supports incremental redundancy information retransmission.
  • the method may be performed by a device at a transmitting end, and the method includes the following content. .
  • the retransmission information is composed of first information and incremental redundancy information; the first information includes information that is mapped to an unreliable bit when initially transmitted, and corresponding to a specific column in the initial transmission check matrix.
  • the information and the puncturing information are higher than the information corresponding to the other columns in the initial transmission check matrix.
  • mapping The process of converting a binary bit sequence into a modulation symbol is called mapping.
  • APSK Amplitude Phase Shift Keying
  • L L bits of information
  • each bit of the bit sequence is grouped into one group during mapping, and each group of bit sequences is separately mapped into one modulation symbol by a table lookup method or the like.
  • L the equivalent signal-to-noise ratio is different after the bits in each packet are transmitted through the channel.
  • the bit reliability corresponding to different positions in each packet is different. .
  • a symbol carrying L bits containing L/2 locations of different reliability levels The lower the reliability level of the location, the less reliable the location is. Therefore, when retransmitting, the information mapped to the low reliability location at the time of initial transmission can be used as the first information for retransmission.
  • a bit sequence corresponding to a 16QAM modulation symbol is represented as (b1, b2, b3, b4); it can be assumed that (b1, b2) corresponds to the real part, (b3, b4) corresponds to the imaginary part, and b1, b3 are The high bits, b2, and b4 are low bits, then b1 and b3 are high reliability bits, and b2 and b4 are low reliability bits.
  • information that is mapped to a low-reliability bit of the modulation symbol that is, an unreliable bit, may be selected for retransmission.
  • the check matrix of the Raptor-like LDPC code has a rich variety of columns, and different columns in the check matrix correspond to different information, and the information corresponding to different columns in the check matrix is decoded for the receiving end.
  • the importance of some columns significantly affects the performance of the decoder, that is, the information corresponding to these columns is more important; the impact of the information corresponding to other columns on the performance of the decoder is not obvious, that is, the information corresponding to these columns is not important.
  • the information corresponding to the column that significantly affects the performance of the decoder is retransmitted, in other words, the specific information corresponding to the column with high importance of information is retransmitted to improve the performance gain of the retransmission.
  • a column in the initial pass check matrix that can significantly affect the performance of the decoder can be obtained by a simulation method. More specifically, the signal-to-noise ratio of the information corresponding to different columns of the check matrix after the channel is different, and the degree of influence on the performance of the decoder is different. Among them, the signal-to-noise ratio of the information with higher importance is more obvious to the performance of the decoder. This feature can be used to obtain the importance of the information corresponding to different columns of the check matrix by simulation. In one example, the degree of improvement in decoder performance can be observed by sequentially increasing the signal-to-noise ratio of the information in the different columns of the corresponding check matrix after the channel. Information that is more effective in improving the performance of the decoder is more important; on the contrary, it is less important.
  • the information after passing through the channel can be added by adding information corresponding to different columns in the initial check matrix.
  • the improvement of the performance of the decoder under the condition of noise ratio, the importance of obtaining the information corresponding to different columns on the performance of the decoder, thereby obtaining the column in the initial check matrix which can significantly affect the performance of the decoder, in other words, obtaining a specific, Corresponding information is of high importance to the column.
  • a certain algorithm may be utilized to calculate the importance of information corresponding to different columns in the initial pass check matrix.
  • the threshold analysis algorithm may be used to calculate the importance of analyzing information corresponding to different columns of the check matrix, thereby obtaining which columns in the check matrix are relatively important, and which columns are relatively unimportant.
  • the information corresponding to the column of the important information may be retransmitted during retransmission to improve the performance gain of the retransmission.
  • the first information may be selected in the initial transmission information according to the reliability location of the bit sequence mapped to the modulation symbol and the column redistribution according to the initial transmission check matrix.
  • Information may be preferable to have high importance in the initial transmission information and to be mapped to the information on the unreliable bits of the modulation symbol at the time of initial transmission; or to select information of high importance or to be mapped to the unreliable position of the modulation symbol at the time of initial transmission.
  • a part of the sequence at the beginning of the sequence of the information may be punctured before the information to be transmitted is encoded; the puncturing information is not transmitted at the time of initial transmission.
  • the decoding of the initial transmission information fails, and when the retransmission is triggered, if the punctured information that was not transmitted at the initial transmission is transmitted during retransmission, the correct decoding effect on the retransmission information is obvious. Therefore, during retransmission, the puncturing information can be retransmitted to improve the performance gain of the retransmission.
  • the retransmission information may be bit sequence rearranged or interleaved. Therefore, the first information can be mapped to the reliable bit during retransmission, which can reduce the loss of the first information in the retransmission process, so as to improve the performance gain of the retransmission.
  • the first information and the incremental redundancy information are combined to obtain retransmission information, mapped and modulated, and then transmitted.
  • the first information in the retransmission information may be subjected to bit sequence rearrangement or interleaving, so that information mapped to the unreliable bit at the time of initial transmission is mapped to a reliable bit at the time of retransmission, thereby enabling
  • the information with large loss of transmission time can have less loss during retransmission to improve the performance of retransmission. beneficial.
  • the initial check matrix may be extended according to the code length of the incremental redundancy information in the retransmission information to obtain a retransmission check matrix. It is easy to understand that the code length of the incremental redundancy information is only the partial code length of the retransmission information. Therefore, the size of the retransmission check matrix according to the code length extension of the incremental redundancy information is smaller than the retransmission information code length extension. The size of the check matrix obtained, therefore, can reduce the computational complexity of decoding.
  • the Raptor-like LDPC code of the check matrix with a nested structure is taken as an example, and the retransmission information code length is assumed to be N1; the code length of the first information is assumed to be k1, and the incremental redundancy information is used.
  • the code length is N1-k1.
  • the initial parity check matrix may be extended by the N1-k1 column and the N1-k1 row in the upper left corner of the parity check matrix of the Raptor-like LDPC code to obtain a retransmission check matrix.
  • the retransmission check matrix obtained by extending the initial check matrix by the N1-k1 column and the N1-k1 row is smaller than the check matrix obtained by extending the initial check matrix by the N1 column and the N1 row.
  • the hybrid automatic retransmission method provided by the embodiment of the present invention can retransmit the information with higher importance for retransmission decoding and the incremental redundancy information when retransmission is performed, thereby improving the retransmission performance gain. Moreover, the complexity of retransmission information decoding is reduced, and the system delay is reduced.
  • the method includes: receiving retransmission information, where the retransmission information is composed of first information and incremental redundancy information; the first information includes information mapped to an unreliable bit at the time of initial transmission, and an initial transmission check matrix One or more of the information corresponding to the specific column and the puncturing information; wherein the information corresponding to the specific column in the initial transmission check matrix is higher than the information corresponding to the other columns in the initial transmission check matrix .
  • the retransmission information After receiving the retransmission information, it demodulates and demaps, and then splits the retransmission information, so that the first information and the initial transmission information are soft combined, and then jointly decoded with the incremental redundancy information. Since the first information includes information mapped to the unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and one or more of the puncturing information, the performance gain of the retransmission can be improved. And the incremental redundancy information combines the first information, which can reduce the complexity of decoding.
  • the method further includes: performing inverse bit sequence rearrangement or deinterleaving on the retransmission information, so that the information sequence that is rearranged or interleaved by the bit sequence at the transmitting end can Restore the original sequence to merge with the initial message.
  • the method further includes: performing inverse bit sequence rearrangement or deinterleaving on the first information, so that the information sequence that is rearranged or interleaved by the bit sequence at the transmitting end can Restore the original sequence to merge with the initial message.
  • the method further includes extending the initial transmission check matrix according to a code length of the incremental redundancy information to obtain a retransmission check matrix. It is easy to understand that the code length of the incremental redundancy information is only the partial code length of the retransmission information. Therefore, the size of the retransmission check matrix according to the code length extension of the incremental redundancy information is smaller than the retransmission information code length extension. The size of the check matrix obtained, therefore, can reduce the computational complexity of decoding.
  • the hybrid automatic retransmission method provided by the embodiment of the present invention can retransmit the information with higher importance for retransmission decoding and the incremental redundancy information when retransmission is performed, thereby improving the retransmission performance gain. Moreover, the complexity of retransmission information decoding is reduced, and the system delay is reduced.
  • the hybrid automatic retransmission method provided by the embodiment of the present invention is specifically introduced in conjunction with FIG. 4 and FIG. 5.
  • the check matrix of the LDPC code has a nested structure, and the base matrix size of the check matrix is 50 rows and 75 columns.
  • the code length is 36*Z
  • the code rate is 24/36
  • the first information and the incremental redundancy information code length ratio may have the following two schemes.
  • the retransmission information has a code length of 36*Z when retransmitting, and the code length of the incremental redundancy information accounts for 75% of the code length of the retransmission information, that is, in this example, the IR combining information accounts for retransmission. 75% of the information.
  • the code length of the calculated incremental redundancy information is 27*Z.
  • the code length of the first information is 9*Z; the base matrix of the retransmission check matrix is extended by 27 rows and 27 columns on the basis of the initial basis matrix. .
  • the incremental redundancy information is generated according to the check matrix at the time of retransmission.
  • the retransmission information has a code length of 36*Z when retransmitting, and the code length of the incremental redundancy information is occupied.
  • the code length of the retransmission information is 50%, that is, in this example, the IR merge information accounts for 50% of the retransmission information.
  • the code length of the calculated incremental redundancy information is 18*Z.
  • the code length of the first information is 18*Z; the base matrix of the retransmission check matrix is extended by 18 rows and 18 columns on the basis of the initial basis matrix. .
  • the incremental redundancy information is generated according to the check matrix at the time of retransmission.
  • the first information may be information corresponding to the column with high importance of the corresponding information in the initial check matrix; more specifically, the column with high importance of the corresponding information may be optimized and selected by the above simulation method.
  • the first information and the incremental redundancy information are combined into retransmission information, and the retransmission information is subjected to bit sequence rearrangement or interleaving so that the first information can be mapped at a high reliability position of the modulation symbol. After being mapped and modulated, it is sent to the receiving end. After the receiver performs corresponding processing, the frame error rate performance can be obtained.
  • the information bit length is 1600 and the modulation mode 256QAM is taken as an example.
  • the frame error rate performance of the above two schemes is as shown in FIG. 4, and the error frame rate performance when the IR merge information accounts for 75% of the retransmission information is almost the same as the error frame rate performance of the IR merge; the IR merge information accounts for the retransmission information.
  • the 50% frame error rate performance differs from the IR combined frame error rate performance by no more than 0.5 dB.
  • the size of the check matrix of the above two schemes is much smaller than the size of the IR merge. Therefore, the computational complexity in decoding is much smaller than the computational complexity in IR combining.
  • the hybrid automatic retransmission method provided by the embodiment of the present invention is specifically introduced in conjunction with FIG. 6 and FIG. 7.
  • the above Raptor-like LDPC code is still taken as an example.
  • the code length of the retransmission information is 32*Z
  • the code length of the incremental redundancy information accounts for 75% of the code length of the retransmission information, that is, in this example, the IR merge information accounts for 75 of the retransmission information. %.
  • the code length of the calculated incremental redundancy information is 24*Z, and correspondingly, the code length of the first information is 8*Z; the parity check matrix of the retransmission The matrix is extended by 24 rows and 24 columns on the basis of the initial basis matrix.
  • the incremental redundancy information is generated according to the check matrix at the time of retransmission.
  • the first information can be selected in the following two ways.
  • Solution 1 all the information that is mapped to the lowest reliability position of the modulation symbol at the time of initial transmission can be selected, and after the information and the incremental redundancy information are combined into the retransmission information, the retransmission information is rearranged or interleaved. In order for the information to be mapped to the highest reliability position of the modulation symbol when retransmitted, the incremental redundancy information is mapped to the remaining reliability locations of the modulation symbols.
  • all information that is mapped to the lowest reliability position of the modulation symbol and the information of the second low reliability position at the time of initial transmission may be selected, and after the information and the incremental redundancy information are combined into the retransmission information, the retransmission is performed.
  • the information is subjected to bit sequence rearrangement or interleaving; so that the information at the lowest reliability position in the initial transmission of the information can be mapped to the highest reliable bit of the modulation symbol during retransmission, and the information at the second low reliability position at the time of initial transmission.
  • the next highest reliability position can be mapped to the modulation symbol, and the incremental redundancy information is mapped to the remaining reliability locations of the modulation symbols.
  • the information bit length is 1600 and the modulation mode 256QAM is taken as an example.
  • the frame error rate performance of the above two schemes is shown in Figure 6.
  • the frame error rate performance of scheme 1 is better than the frame error rate performance of pure IR combining.
  • BLER block error rate
  • scheme 1 The performance gain of the scheme is 0.6 dB; and the frame error rate performance of scheme 2 is almost the same as the frame error rate performance of pure IR combining.
  • the size of the check matrix of the above two schemes is much smaller than the size of pure IR combining. Therefore, the computational complexity in decoding is much smaller than the computational complexity in pure IR combining.
  • the retransmission information may include information for chase combining and information for IR combining, and the retransmission matrix may use information for chase combining and information for IR combining.
  • Joint decoding which combines the advantages of chase combining and IR combining. It can achieve higher signal-to-noise ratio gain and coding gain, and reduce the complexity of retransmission information decoding and reduce system delay.
  • the embodiment of the present invention provides a hybrid automatic repeating apparatus 800 for an LDPC code, where the apparatus 800 includes a sending unit 801, configured to send retransmission information, where the retransmission information includes first information and incremental redundancy information.
  • the first information includes one or more of information that is mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; wherein the first pass school
  • the information corresponding to the specific column in the matrix is more important than the information corresponding to the other columns in the initial check matrix.
  • the apparatus 800 further includes a bit sequence rearranging unit or an interleaving unit 802.
  • the function of the bit sequence rearranging unit or the interleaving unit 802 can be referred to the content of the method part above, and details are not described herein.
  • the device 800 further includes an extension unit 803.
  • the function of the extension unit 803 can be referred to the content of the method part above, and details are not described herein.
  • the device 900 includes a receiving unit 901, configured to receive retransmission information, where the retransmission information is composed of first information and incremental redundancy information; the first information includes information that is mapped to an unreliable bit when initially transmitted, and initially Transmitting one or more of information corresponding to a specific column in the check matrix, and puncturing information; wherein, the information corresponding to the specific column in the initial check matrix is more important than the initial check matrix Information corresponding to other columns.
  • the apparatus 900 further includes an inverse bit sequence rearranging unit or a deinterleaving unit 902, the function of which can be referred to the content of the method part above, and details are not described herein.
  • the device 900 further includes an extension unit 903, the function of which can be referred to the content of the method section above, and details are not described herein.
  • the beneficial effects of the device 900 can be referred to the contents of the method section above, and are not described herein.
  • the embodiment of the present invention provides a hybrid automatic repeat communication device 1000 for an LDPC code.
  • the communication device 1000 includes a radio frequency circuit 1000 for transmitting retransmission information, where the retransmission information is first information and incremental redundancy.
  • Information composition the first information includes one or more of information mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; wherein the initial transmission
  • the information corresponding to the specific column in the check matrix is more important than the information corresponding to the other columns in the initial check matrix.
  • the communication device 1000 further includes a processor 1002, the function of which can be referred to the content of the method part above, and details are not described herein.
  • the beneficial effects of the communication device 1000 can be referred to the contents of the method section above, and are not described herein.
  • the embodiment of the present invention provides a hybrid automatic repeat communication device 1100 for an LDPC code.
  • the communication device 1100 includes a radio frequency circuit 1101 for receiving retransmission information, where the retransmission information is first information and incremental redundancy.
  • Information composition the first information includes one or more of information mapped to an unreliable bit at the time of initial transmission, information corresponding to a specific column in the initial transmission check matrix, and puncturing information; wherein the initial transmission
  • the information corresponding to the specific column in the check matrix is more important than the information corresponding to the other columns in the initial check matrix.
  • the communication device 1100 further includes a processor 1102, the function of which can be referred to the content of the method part above, and details are not described herein.
  • the beneficial effects of the communication device 1100 can be referred to the content of the method section above, and are not described herein.
  • processors in the embodiment of the present application may be a central processing unit (CPU), and may be other general-purpose processors, digital signal processors (DSPs), and application specific integrated circuits. (Application Specific Integrated Circuit, ASIC), Field Programmable Gate Array (FPGA) or other programmable logic device, transistor logic device, hardware component, or any combination thereof.
  • a general purpose processor can be a microprocessor or any conventional processor.
  • the method steps in the embodiments of the present application may be implemented by means of hardware, or may be implemented by a processor executing software instructions.
  • the software instructions can be composed of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (Programmable ROM). , PROM), Erasable PROM (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Register, Hard Disk, Mobile Hard Disk, CD-ROM, or well known in the art Any other form of storage medium.
  • An exemplary storage medium is coupled to the processor to enable the processor to read information from, and write information to, the storage medium.
  • the storage medium can also be an integral part of the processor.
  • the processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a transmitting device or a receiving device. Of course, the processor and the storage medium can also exist as discrete components in the transmitting device or the receiving device.
  • the above embodiments it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof.
  • software it may be implemented in whole or in part in the form of a computer program product.
  • the computer program product includes one or more computer instructions.
  • the computer program instructions When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present invention are generated in whole or in part.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions can be stored in or transmitted by a computer readable storage medium.
  • the computer instructions can be from a website site, computer, server or data center to another website site by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.) Transfer from a computer, server, or data center.
  • the computer readable storage medium can be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that includes one or more available media.
  • the usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (such as a solid state disk (SSD)).

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Abstract

本申请涉及一种用于LDPC码的混合自动重传方法，所述方法包括：发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。

Description

一种混合自动重传请求的方法和装置 技术领域
本发明涉及移动通信领域，特别涉及一种混合自动重传请求的方法和装置。
背景技术
在无线通信系统中，无线信道的时变特性、多径衰落以及一些不可预测的干扰经常会导致信号传输的失败。通常会采用前向纠错(Forward Error Correction，FEC)编码技术和自动重传请求(Automatic Repeat reQuest，ARQ)相结合的方法，即混合自动重传请求(Hybrid Automatic Repeat reQuest，HARQ)，来进行差错控制。
混合自动重传请求一般有两种实现方案，即Chase合并(Chase Combining，CC)和增量冗余(incremental redundancy，IR)。Chase合并的原理是，重传时发送端向接收端发送的数据包与初传时的数据包相同，接收端将初传的编码包和重传的编码包进行合并，然后解码。但是Chase合并的性能增益不高，低于IR合并。IR合并的原理是，重传时发送端向接收端发送的数据是基于初传时的数据编码得到的冗余信息，接收端接收到重传发送的冗余信息后，将其与初传的数据拼接，在利用更低码率的校验矩阵联合译码以恢复数据。IR合并的性能增益虽然高于Chase合并，但是接收端译码复杂度高，易导致系统时延。
在现有技术中，在采用Chase合并时，只是将初传信息或者初传的部分信息发送给接收端，并未对重传的信息进行选择，因此，性能增益有限。此外，对于低密度奇偶校验(low-density parity-check，LDPC)码，现有技术 只是采用纯Chase合并的方式或者纯IR合并的方式进行重传，因此，存在性能增益有限以及译码复杂度高等问题。
发明内容
本文描述了一种用于LDPC码的混合自动重传请求的方法和装置，可以结合Chase合并和IR合并，并且可以将对译码的具有重要作用的信息进行重传，从而可以既提高了重传性能增益，又降低了重传信息译码的复杂度，降低了系统时延。
第一方面，本发明实施例提供了一种用于LDPC码的混合自动重传方法，所述方法包括：发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
在本实施例中，可以将对重传具有较高重要性的信息结合增量冗余信息进行重传，从而可以兼具Chase合并和IR合并的优点，提高了重传的性能增益，降低了重传信息译码的复杂度，降低了系统时延。
结合第一方面，在第一方面的第一种可能的实现方式中，所述发送重传信息之前，所述方法还包括：对所述重传信息进行比特序列重排或交织，以使所述第一信息被映射到可靠位。
在本实施例中，对重传信息进行比特序列重排或交织，使得对重传具有较高重要性的信息能够被映射到可靠位上，从而进一步提供了重传的性能增益。
结合第一方面，在第一方面的第二种可能的实现方式中，所述发送重传信息之前，所述方法还包括：对所述第一信息进行比特序列重排或交织，以使所述第一信息中初传时被映射到不可靠位的信息被映射到可靠位。
在本实施例中，对第一信息进行比特序列重排或交织，使第一信息中初 传时被映射到不可靠位的信息被映射到可靠位，从而进一步提供了重传的性能增益。
结合第一方面，在第一方面的第三种可能的实现方式中，所述方法还包括：根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
在本实施例中，可以根据增量冗余信息的码长扩展初传校验矩阵得到重传校验矩阵，从而降低了重传信息译码的复杂度，降低了系统时延。
第二方面，本发明实施例还提供了另一种用于LDPC码的混合自动重传方法，所述方法包括：接收重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
第三方面，本发明实施例提供了一种用于LDPC码的混合自动重传装置，所述装置包括：发送单元，用于发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
第四方面，本发明实施例还提供了另一种用于LDPC码的混合自动重传装置，所述装置包括：接收单元，用于接收重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
第五方面，本发明实施例提供了一种用于LDPC码的混合自动重传通信装置，所述通信装置包括：射频电路，用于发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的 信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
第六方面，本发明实施例提供了一种用于LDPC码的混合自动重传通信装置，所述通信装置包括：射频电路，用于接收重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
本发明实施例提供的用于LDPC码的混合自动重传方法、装置，在进行重传时，可以将对重传译码有较高重要性的信息结合增量冗余信息进行重传，从而可以提高了重传性能增益，又降低了重传信息译码的复杂度，降低了系统时延。
附图说明
图1为本发明实施例提供的一种LDPC码的校验矩阵示意图；
图2为本发明实施例提供的一种利用本发明实施例提供的混合自动重传方法进行重传的发送端过程示意图；
图3为本发明实施例提供的一种利用本发明实施例提供的混合自动重传方法进行重传的接收端过程示意图；
图4为本发明实施例提供的一种混合自动重传方法的性能示意图；
图5为本发明实施例提供的另一种混合自动重传方法的性能示意图；
图6为本发明实施例提供的另一种混合自动重传方法的性能示意图；
图7为本发明实施例提供的另一种混合自动重传方法的性能示意图；
图8为本发明实施例提供的一种混合自动重传装置的结构示意图；
图9为本发明实施例提供的另一种混合自动重传装置的结构示意图；
图10为本发明实施例提供的一种混合自动重传通信装置的结构示意图；
图11为本发明实施例提供的一种混合自动重传通信装置的结构示意图；
具体实施方式
下面将结合附图，对本发明实施例中的技术方案进行描述。显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。
本申请各实施例中的发送设备和接收设备可以为以无线方式进行数据传输的任意一种发送端的设备和接收端的设备。发送设备和接收设备可以是任意一种具有无线收发功能的设备，包括但不限于：基站NodeB、演进型基站eNodeB、第五代(the fifth generation，5G)通信系统中的基站、未来通信系统中的基站或网络设备、WiFi系统中的接入节点、无线中继节点、无线回传节点以及用户设备(user equipment，UE)。其中，UE也可以称之为终端Terminal、移动台(mobile station，MS)、移动终端(mobile terminal，MT)等。UE可以经无线接入网(radio access network，RAN)与一个或多个核心网进行通信，或者可以通过自组织或免授权的方式接入分布式网络，UE还可以通过其它方式接入无线网络进行通信，UE也可以与其它UE直接进行无线通信，本申请的实施例对此不作限定。
本申请的实施例所提供的数据传输方法可以适用于下行数据传输，也可以适用于上行数据传输，还可以适用于设备到设备(device to device，D2D)的数据传输。对于下行数据传输，发送设备可以是基站，对应的接收设备可以是UE。对于上行数据传输，发送设备可以是UE，对应的接收设备可以是基站。对于D2D的数据传输，发送设备可以是UE，对应的接收设备也可以是UE。本申请的实施例对此不做限定。
本申请的实施例中的发送设备和接收设备可以部署在陆地上，包括室内或室外、手持或车载；也可以部署在水面上；还可以部署在空中的飞机、气球和卫星上。本申请的实施例中的UE可以是手机(mobile phone)、平 板电脑(Pad)、带无线收发功能的电脑、虚拟现实(Virtual Reality，VR)终端设备、增强现实(Augmented Reality，AR)终端设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程医疗(remote medical)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等等。本申请的实施例对应用场景不做限定。
在Chase合并的方式中，重传的数据包和初传的数据包的解码复杂度相等；并且重传的数据包支持自解码，因此，即使初传的数据包丢失，也可以恢复数据。
Chase合并的性能增益仅来自信噪比的提高，因此，增益是有限的。例如，在16正交幅度调制(Quadrature Amplitude Modulation，QAM)调制下的Chase合并方式中，重传时，发送端的设备将初传时映射到符号的比特序列进行倒序，然后发送给接收端的设备，使得初传和重传合并后的比特信噪比趋于平均，以提高性能增益；此外，重传时，还可以采用不同的星座映射图案，以平均比特序列中0和1的被保护程度。上述方式虽然可以在一定程度上提高Chase合并的信噪比性能增益，但是，总体增益仍低于IR合并方式。
在IR合并方式中，发送端的设备可以将初传数据的全部比特进行编码并附加冗余信息以获得初传数据的增量冗余信息，并且在重传时传输不同的冗余校验位；也可以将初传数据打孔，在重传时，将被打孔的比特位发送给接收端的设备；发送端的设备也可以同时采用上述两种方式进行重传。接收端的设备将重传的数据和初传的数据合并后，利用更大尺寸的的校验矩阵译码以恢复编码信息。
IR合并可以取得信噪比增益和编码增益，但是，重传的数据包不支持自解码，并且重传后的译码校验矩阵变大，增加了译码复杂度和系统时延。
本发明实施例提供了一种混合自动重传方法，可以应用于校验矩阵具有 嵌套(nested)结构的Raptor-like LDPC码，该LDPC码支持增量冗余重传；该LDPC码的校验矩阵具有高码率核心，如图1所示，在重传时，可以扩展得到低码率的重传校验矩阵。在高阶调制下，发送端的设备可以选择部分初传信息，并根据重传校验矩阵生成增量冗余信息，然后合并选择的部分初传信息和增量冗余信息，经映射和调制后发送给接收端的设备。
本发明实施例提供的混合自动重传方法结合了chase合并和IR合并的优点，可以取得较高的信噪比增益和编码增益，并且降低了重传信息译码的复杂度，降低了系统时延。
在一个示例中，初次传输时，可以根据码长以及系统给定的码率从所示的校验矩阵上截取相应部分作为初传校验矩阵，对需要传输的信息进行编码，以得到初传信息，将初传信息进行映射、调制后发送。
在一个示例中，以Raptor-like LDPC码为例；可以假设初次传输的码长为N，码率为R；可以从该Raptor-like LDPC码对应的校验矩阵上截取N列、N(1-R)行，具体地，可以从该校验矩阵的左上角截取N列、N(1-R)行，作为初传校验矩阵；然后根据初传校验矩阵对需要传输的信息进行编码，以得到初传信息，将初传信息进行映射、调制后发送。
结合图2，具体介绍本发明实施例提供的一种用于LDPC码的混合自动重传方法，该LDPC码支持增量冗余信息重传；该方法可由发送端的设备执行，该方法包括以下内容。
发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
通信系统为了获得较高的频带利用率，会采用高阶调制技术，例如正交幅度调制、幅相键控(Amplitude Phase Shift Keying，APSK)等高阶调制技术。将二进制比特序列转换为调制符号的过程称为映射。假设一个调制符 号可以携带L个比特的信息，映射时将比特序列每L个分为一组，再通过查表等方法将各组比特序列分别映射为一个调制符号。当L>2时，每个分组中的比特在经过信道传输以后，其等效的信噪比是不同的，对接收端来说，相当于每个分组中不同位置的比特可靠度是不同的。一个携带L个比特的符号，包含了L/2个不同的可靠度级别的位置。位置的可靠度级别越低，该位置就越不可靠，因此，在重传时，可以将初传时被映射到低可靠度位置的信息，作为第一信息用以重传。
具体举例而言，一个16QAM调制符号对应的比特序列表示为(b1,b2,b3,b4)；可以假设(b1,b2)对应实部，(b3,b4)对应虚部，并且b1,b3为高位，b2,b4为低位，则b1,b3为高可靠位，b2,b4为低可靠位。在重传时，可以选择初传时被映射到调制符号低可靠位，即不可靠位，的信息进行重传。
以Raptor-like LDPC码为例，Raptor-like LDPC码的校验矩阵中列重种类丰富，校验矩阵中不同列对应不同的信息，并且，校验矩阵中不同列对应的信息对于接收端解码的重要性不同，有些列对应的信息显著影响解码器的性能，即这些列对应的信息比较重要；其他列对应的信息对解码器性能的影响则不明显，即这些列对应的信息不重要。在进行重传时，将能显著影响解码器性能的列对应的信息进行重传，换言之，将特定的、对应的信息重要性高的列对应的信息进行重传，以提高重传的性能增益。
在一个示例中，可以通过仿真方法，获取初传校验矩阵中能显著影响解码器性能的列。更具体地，校验矩阵不同列对应的信息经过信道后的信噪比，对解码器性能影响程度不同，其中，重要性较高的信息的信噪比，对解码器性能改善较为明显，利用这一特征，可以通过仿真方法获取校验矩阵不同列对应的信息的重要性。在一个例子中，可以通过依次增加对应校验矩阵中不同列的信息经过信道后的信噪比，观察解码器性能改善的程度。对解码器性能改善较为明显的信息，其重要性较高；反之，则其重要性较低。
因此，可以通过增加初传校验矩阵中不同列对应的信息经过信道后的信 噪比的条件下的解码器性能的改善程度，获取不同列对应的信息对解码器性能的重要性，从而获取初传校验矩阵中能显著影响解码器性能的列，换言之，获取特定的、对应的信息重要性高的列。在一个示例中，可以利用一定的算法计算所述初传校验矩阵中不同列对应的信息的重要性。具体举例而言，可以利用门限分析算法，计算分析校验矩阵不同列对应的信息的重要性，从而获得该校验矩阵中哪些列对应的信息相对重要，哪些列对应的信息相对不重要，进而可以在重传时，将对应重要信息的列对应的信息进行重传，以提高重传的性能增益。
在一个示例中，可以根据初传信息映射到调制符号的比特序列的可靠度位置和根据初传校验矩阵的列重分布，在初传信息中选取所述第一信息。
可以优选初传信息中重要性高，且在初传时被映射到调制符号不可靠位上的信息；还可以选择重要性高的信息，或者在初传时被映射到调制符号不可靠位上的信息。
在一个示例中，初传时，在需要传输的信息进行编码前，可以将该信息的序列开头的一部分序列打孔；初传时不传输打孔信息。初传信息译码失败，引发重传时，如果将初传时未传输的打孔信息在重传时进行传输，对于重传信息的正确译码作用明显。因此，在重传时，可以将打孔信息进行重传，以提高重传的性能增益。
在一个示例中，可以对重传信息进行比特序列重排或交织。从而使的第一信息在重传时能够被映射到可靠位上，可以降低第一信息在重传过程中的损耗，以提高重传的性能增益。
将第一信息和增量冗余信息进行合并，以得到重传信息，映射和调制后发送。
在一个示例中，可以对重传信息中的第一信息进行比特序列重排或交织，从而使得初传时被映射到不可靠位的信息在重传时被映射到可靠位，从而可以使初传时损耗大的信息在重传时可以有较少的损耗，以提高重传的性能增 益。
在一个示例中，可以根据重传信息中的增量冗余信息的码长对初传校验矩阵进行扩展，以得到重传校验矩阵。容易理解的是，增量冗余信息的码长只是重传信息的部分码长，因此，根据增量冗余信息的码长扩展的重传校验矩阵的尺寸，小于重传信息码长扩展而得的校验矩阵的尺寸，因此，可以降低译码的计算复杂度。
具体举例而言，以具有嵌套结构的校验矩阵的Raptor-like LDPC码为例，可以假设重传信息码长为N1；可以假设第一信息的码长为k1，则增量冗余信息的码长为N1-k1。则可以在Raptor-like LDPC码具有嵌套结构的校验矩阵的左上角将初传校验矩阵扩展N1-k1列和N1-k1行，以得到重传校验矩阵。显然，将初传校验矩阵扩展N1-k1列和N1-k1行得到的重传校验矩阵，小于，将初传校验矩阵扩展N1列和N1行得到的校验矩阵。
本发明实施例提供的混合自动重传方法，在进行重传时，可以将对重传译码有较高重要性的信息结合增量冗余信息进行重传，从而可以提高了重传性能增益，又降低了重传信息译码的复杂度，降低了系统时延。
下文结合图3，对本发明实施例提供的另一种混合自动重传方法进行介绍，该方法的执行主体可以是接收端的设备。该方法包括：接收重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
接收到重传信息后，经过解调和解映射，然后将重传信息分路，以使第一信息和初传信息进行软合并，之后再和增量冗余信息进行联合译码。因为第一信息包括了初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种，因此，可以提高重传的性能增益；并且增量冗余信息结合了第一信息，可以降低译码的复杂度。
在一个示例中，在上述接收重传信息之后，该方法还包括：对所述重传信息进行逆比特序列重排或解交织，以使在发送端被比特序列重排或交织的信息序列能够恢复原来的序列，以和初传信息合并。
在一个示例中，在上述接收重传信息之后，该方法还包括：对所述第一信息进行逆比特序列重排或解交织，以使在发送端被比特序列重排或交织的信息序列能够恢复原来的序列，以和初传信息合并。
在一个示例中，所述方法还包括：根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。容易理解的是，增量冗余信息的码长只是重传信息的部分码长，因此，根据增量冗余信息的码长扩展的重传校验矩阵的尺寸，小于重传信息码长扩展而得的校验矩阵的尺寸，因此，可以降低译码的计算复杂度。
本发明实施例提供的混合自动重传方法，在进行重传时，可以将对重传译码有较高重要性的信息结合增量冗余信息进行重传，从而可以提高了重传性能增益，又降低了重传信息译码的复杂度，降低了系统时延。
在一个示例中，结合图4和图5对本发明实施例提供的混合自动重传方法进行具体介绍。以一种Raptor-like LDPC码为例，该LDPC码的校验矩阵具有嵌套结构，该校验矩阵的基矩阵尺寸为50行75列。
假设初传时，码长为36*Z，码率为24/36，则可以从基矩阵的左上角切割12行36列作为初传时的校验矩阵。
重传时，第一信息和增量冗余信息码长比例可以有如下两种方案。
方案1，假设重传时，重传信息的码长为36*Z，增量冗余信息的码长占重传信息的码长的75％，即在该例子中，IR合并信息占重传信息的75％。经计算增量冗余信息的码长为27*Z，相应的，第一信息的码长为9*Z；重传校验矩阵基矩阵在初传基矩阵的基础上扩展27行、27列。根据重传时的校验矩阵生成增量冗余信息。
方案2，假设重传时，重传信息的码长为36*Z，增量冗余信息的码长占 重传信息的码长的50％，即在该例子中，IR合并信息占重传信息的50％。经计算增量冗余信息的码长为18*Z，相应的，第一信息的码长为18*Z；重传校验矩阵基矩阵在初传基矩阵的基础上扩展18行、18列。根据重传时的校验矩阵生成增量冗余信息。
第一信息可以为根据初传校验矩阵中对应信息的重要性高的列对应的信息；更具体地，该对应的信息重要性高的列可以通过上述仿真方法进行优化选取而得。将第一信息和增量冗余信息合并为重传信息，并将重传信息进行比特序列重排或交织，以使第一信息能够被映射在调制符号的高可靠度位置上。经过映射和调制后发送给接收端。接收端进行相应处理后，可得出误帧率性能。
在加性高斯白噪声(Additive White Gaussian Noise，AWGN)信道条件下，以信息位长度为1600，调制方式256QAM为例。上述两种方案的误帧率性能如图4所示，IR合并信息占重传信息的75％时的误帧率性能与IR合并的误帧率性能几乎一致；IR合并信息占重传信息的50％误帧率性能与IR合并的误帧率性能相差不超过0.5dB。
在瑞利衰落信道(Rayleigh Fading Channel)条件下，上述两种方案的误帧率性能如图5所示，其误帧率性能都非常接近纯IR合并的误帧率性能。
重传时，上述两种方案的校验矩阵的尺寸都远小于IR合并的尺寸，因此，在译码的计算复杂度远小于IR合并时的计算复杂度。
在一个示例中，结合图6和图7对本发明实施例提供的混合自动重传方法进行具体介绍。仍以上述Raptor-like LDPC码为例。
假设初传时，码长为32*Z，码率为25/32，则可以从基矩阵的左上角切割7行32列作为初传时的校验矩阵。
假设重传时，重传信息的码长为32*Z，增量冗余信息的码长占重传信息的码长的75％，即在该例子中，IR合并信息占重传信息的75％。经计算增量冗余信息的码长为24*Z，相应的，第一信息的码长为8*Z；重传的校验矩阵基 矩阵在初传基矩阵的基础上扩展24行、24列。根据重传时的校验矩阵生成增量冗余信息。
第一信息的选择可以有如下两种方案。
方案1、可以选择所有初传时被映射到调制符号的最低可靠度位置的信息，在将该信息和增量冗余信息合并成重传信息后，对重传信息进行比特序列重排或交织；以使该信息在重传时能够被映射到调制符号的最高可靠度位置，增量冗余信息被映射到调制符号的其余可靠度位置。
方案2、可以选择所有初传时被映射到调制符号的最低可靠度位置的信息和次低可靠度位置的信息，在将该信息和增量冗余信息合并成重传信息后，对重传信息进行比特序列重排或交织；以使该信息中初传时处于最低可靠度位置的信息在重传时能够被映射到调制符号的最高可靠位，初传时处于次低可靠度位置的信息能够被映射到调制符号的次高可靠度位置，增量冗余信息被映射到调制符号的其余可靠度位置。
在加性高斯白噪声信道条件下，以信息位长度为1600，调制方式256QAM为例。上述两种方案的误帧率性能如图6所示，方案1的误帧率性能优于纯IR合并的误帧率性能，在误块率(BLock Error Rate，BLER)为0.01时，方案1的性能增益为0.6dB；而方案2的误帧率性能和纯IR合并的误帧率性能几乎一致。
在瑞利衰落信道条件下，上述两种方案的误帧率性能如图7所示，方案1误帧率性能都非常接近纯IR合并的误帧率性能，方案2的误帧率性能与纯IR合并的误帧率性能相差也不大。
上述两种方案的校验矩阵的尺寸都远小于纯IR合并的尺寸，因此，在译码的计算复杂度远小于纯IR合并时的计算复杂度。
利用本发明实施例提供的混合自动重传方法，重传信息可以包括用于chase合并的信息和用于IR合并的信息，重传矩阵可以对用于chase合并的信息和用于IR合并的信息进行联合译码，兼具chase合并和IR合并的优点， 既可以取得较高的信噪比增益和编码增益，而且降低了重传信息译码的复杂度，降低了系统时延。
本发明实施例提供了一种用于LDPC码的混合自动重传装置800，该装置800包括发送单元801，用于发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
装置800还包括比特序列重排单元或交织单元802，比特序列重排单元或交织单元802的功能可参照上文中有关方法部分的内容介绍，此处不在赘述。
装置800还包括扩展单元803，扩展单元803功能可参照上文中有关方法部分的内容介绍，此处不在赘述。
装置800的有益效果可参照上文中有关方法部分的内容介绍，此处不在赘述。
本发明实施例还提供了另一种用于LDPC码的混合自动重传装置900。装置900包括接收单元901，用于接收重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
装置900还包括逆比特序列重排单元或解交织单元902，其功能可参照上文中有关方法部分的内容介绍，此处不在赘述。
装置900还包括扩展单元903，其功能可参照上文中有关方法部分的内容介绍，此处不在赘述。
装置900的有益效果可参照上文中有关方法部分的内容介绍，此处不在赘述。
本发明实施例提供了一种用于LDPC码的混合自动重传通信装置1000，通信装置1000包括射频电路1000，用于发送重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
通信装置1000还包括处理器1002，其功能可参照上文中有关方法部分的内容介绍，此处不在赘述。
通信装置1000的有益效果可参照上文中有关方法部分的内容介绍，此处不在赘述。
本发明实施例提供了一种用于LDPC码的混合自动重传通信装置1100，通信装置1100包括射频电路1101，用于接收重传信息，所述重传信息由第一信息和增量冗余信息组成；所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
通信装置1100还包括处理器1102，其功能可参照上文中有关方法部分的内容介绍，此处不在赘述。
通信装置1100的有益效果可参照上文中有关方法部分的内容介绍，此处不在赘述。
可以理解的是，本申请的实施例中的处理器可以是中央处理单元(Central Processing Unit，CPU)，还可以是其他通用处理器、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application Specific Integrated Circuit，ASIC)、现场可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、晶体管逻辑器件，硬件部件或者其任意组合。通用处理器可以是微处理器，也可以是任何常规的处理器。
本申请的实施例中的方法步骤可以通过硬件的方式来实现，也可以由处理器执行软件指令的方式来实现。软件指令可以由相应的软件模块组成，软件模块可以被存放于随机存取存储器(Random Access Memory，RAM)、闪存、只读存储器(Read-Only Memory，ROM)、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、电可擦除可编程只读存储器(Electrically EPROM，EEPROM)、寄存器、硬盘、移动硬盘、CD-ROM或者本领域熟知的任何其它形式的存储介质中。一种示例性的存储介质耦合至处理器，从而使处理器能够从该存储介质读取信息，且可向该存储介质写入信息。当然，存储介质也可以是处理器的组成部分。处理器和存储介质可以位于ASIC中。另外，该ASIC可以位于发送设备或接收设备中。当然，处理器和存储介质也可以作为分立组件存在于发送设备或接收设备中。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本发明实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者通过所述计算机可读存储介质进行传输。所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘Solid State Disk(SSD))等”
可以理解的是，在本申请的实施例中涉及的各种数字编号仅为描述方便进行的区分，并不用来限制本申请的实施例的范围。
可以理解的是，在本申请的实施例中，上述各过程的序号的大小并不 意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请的实施例的实施过程构成任何限定。
以上所述，仅为本申请的实施例的具体实施方式，任何熟悉本技术领域的技术人员在本申请公开揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本申请的实施例的保护范围之内。

Claims (24)

  1. 一种用于LDPC码的混合自动重传方法，其特征在于，所述方法包括：
    发送重传信息，所述重传信息由第一信息和增量冗余信息组成；
    所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息的一种或多种；
    其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
  2. 根据权利要求1所述的方法，其特征在于，所述发送重传信息之前，所述方法还包括：对所述重传信息进行比特序列重排或交织，以使所述第一信息被映射到可靠位。
  3. 根据权利要求1所述的方法，其特征在于，所述发送重传信息之前，所述方法还包括：对所述第一信息进行比特序列重排或交织，以使所述第一信息中初传时被映射到不可靠位的信息被映射到可靠位。
  4. 根据权利要求1所述的方法，其特征在于：所述方法还包括：根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
  5. 一种用于LDPC码的混合自动重传方法，其特征在于，所述方法包括：
    接收重传信息，所述重传信息由第一信息和增量冗余信息组成；
    所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；
    其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
  6. 根据权利要求5所述的方法，其特征在于，所述接收重传信息之后，所述方法还包括：对所述重传信息进行逆比特序列重排或解交织。
  7. 根据权利要求5所述的方法，其特征在于，所述接收重传信息之后，所述方法还包括：对所述第一信息进行逆比特序列重排或解交织。
  8. 根据权利要求5所述的方法，其特征在于，所述方法还包括：根据所 述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
  9. 一种用于LDPC码的混合自动重传装置，其特征在于，所述装置包括：
    发送单元，用于发送重传信息，所述重传信息由第一信息和增量冗余信息组成；
    所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；
    其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
  10. 根据权利要求9所述的装置，其特征在于，所述装置还包括：
    比特序列重排单元或交织单元，用于，在所述发送单元发送重传信息之前，对所述重传信息进行比特序列重排或交织，以使所述第一信息被映射到可靠位。
  11. 根据权利要求9所述的装置，其特征在于，所述装置还包括：
    比特序列重排单元或交织单元，用于，在所述发送单元发送重传信息之前，对所述第一信息进行比特序列重排或交织，以使所述第一信息中初传时被映射到不可靠位的信息被映射到可靠位。
  12. 根据权利要求9所述的装置，其特征在于，所述装置还包括：
    扩展单元，用于根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
  13. 一种用于LDPC码的混合自动重传装置，其特征在于，所述装置包括：
    接收单元，用于接收重传信息，所述重传信息由第一信息和增量冗余信息组成；
    所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；
    其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
  14. 根据权利要求13所述的方法，其特征在于，所述装置还包括：
    逆比特序列重排单元或解交织单元，用于，在所述接收单元接收重传信息之后，对所述重传信息进行逆比特序列重排或解交织。
  15. 根据权利要求13所述的方法，其特征在于，所述装置还包括：
    逆比特序列重排单元或解交织单元，用于，在所述接收单元接收重传信息之后，对所述第一信息进行逆比特序列重排或解交织。
  16. 根据权利要求13所述的装置，其特征在于，所述装置还包括：
    扩展单元，用于根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
  17. 一种用于LDPC码的混合自动重传通信装置其特征在于，所述通信装置包括：
    射频电路，用于发送重传信息，所述重传信息由第一信息和增量冗余信息组成；
    所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；
    其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
  18. 根据权利要求17所述的通信装置，其特征在于，所述通信装置还包括：
    处理器，用于，在所述射频电路发送重传信息之前，对所述重传信息进行比特序列重排或交织，以使所述第一信息被映射到可靠位。
  19. 根据权利要求17所述的通信装置，其特征在于，所述通信装置还包括：
    处理器，用于，在所述射频电路发送重传信息之前，对所述第一信息进行比特序列重排或交织，以使所述第一信息中初传时被映射到不可靠位的信息被映射到可靠位。
  20. 根据权利要求17所述的通信装置，其特征在于，所述通信装置还包括：
    处理器，用于根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
  21. 一种用于LDPC码的混合自动重传通信装置其特征在于，所述通信装置包括：
    射频电路，用于接收重传信息，所述重传信息由第一信息和增量冗余信息组成；
    所述第一信息包括初传时被映射到不可靠位的信息、初传校验矩阵中特定列对应的信息、打孔信息中的一种或多种；
    其中，所述初传校验矩阵中特定列对应的信息的重要性高于所述初传校验矩阵中其他列对应的信息。
  22. 根据权利要求21所述的通信装置，其特征在于，所述通信装置还包括：
    处理器，用于，在所述射频电路接收重传信息之后，对所述重传信息进行逆比特序列重排或解交织。
  23. 根据权利要求21所述的通信装置，其特征在于，所述通信装置还包括：
    处理器，用于，在所述射频电路接收重传信息之后，对所述第一信息进行逆比特序列重排或解交织。
  24. 根据权利要求21所述的通信装置，其特征在于，所述通信装置还包括：
    处理器，用于根据所述增量冗余信息的码长扩展初传校验矩阵，以得到重传校验矩阵。
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CN101047482A (zh) * 2006-04-12 2007-10-03 华为技术有限公司 一种基于译码可靠度的混合自动重传请求方法
CN101286825A (zh) * 2007-04-11 2008-10-15 松下电器产业株式会社 实现基于可靠性的混合自动重传的方法、发送端和系统
CN101562512A (zh) * 2009-05-27 2009-10-21 西安电子科技大学 基于fec的选择重传系统及其重传方法
JP2010057175A (ja) * 2008-08-29 2010-03-11 Fujitsu Ltd 自動再送制御方法と通信システム及びその送信機と受信機

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Publication number Priority date Publication date Assignee Title
CN101047482A (zh) * 2006-04-12 2007-10-03 华为技术有限公司 一种基于译码可靠度的混合自动重传请求方法
CN101286825A (zh) * 2007-04-11 2008-10-15 松下电器产业株式会社 实现基于可靠性的混合自动重传的方法、发送端和系统
JP2010057175A (ja) * 2008-08-29 2010-03-11 Fujitsu Ltd 自動再送制御方法と通信システム及びその送信機と受信機
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