EP-4740342-A1 - METHOD, SYSTEM, AND APPARATUS FOR RETRANSMISSION IN WIRELESS COMMUNICATIONS

Abstract

Embodiments of the present application include communication methods and communication apparatuses. A method includes: transmitting a retransmission including one or more cross-CB coded blocks, where the cross-CB coded blocks includes a first cross-CB coded block, and the first cross-CB coded block is generated by encoding, according to an LDPC code, a part of information bits of the CBs, where a code rate of the retransmission is lower than a code rate of the initial transmission. Thus, a receiving apparatus can decode a cross-CB coded block in a current retransmission. If the cross-CB coded blocks are decoded successfully, the part of the information bits can be considered as frozen bits, which allows the rest of information bits in the previous (re) transmission to be decoded with a lower CR. Embodiments can offer a lower decoding complexity by decoding multiple short codewords, and improve retransmission performance.

Inventors

• VU, Van Hung
• ZHANG, Huazi
• CAO, YU

Assignees

• Huawei Technologies Co., Ltd.

Dates

Publication Date

20260513

Application Date

20240131

Claims (20)

1. A communication method, comprising: transmitting an initial transmission comprising multiple code blocks (CBs) ; and transmitting a retransmission comprising one or more cross-CB coded blocks, wherein the cross-CB coded blocks comprise a first cross-CB coded block, and the first cross-CB coded block is generated by encoding, according to a low density parity check (LDPC) code, a part of information bits of the CBs, wherein a code rate of the retransmission is lower than a code rate of the initial transmission.
2. The method according to claim 1, wherein the part of information bits of the CBs comprises one or more of: bits corresponding to variable nodes of each CB, wherein degrees of the variable nodes are less than a threshold; bits corresponding to ending-most positions of each CB; or bits corresponding to beginning-most positions of each CB.
3. The method according to claim 1 or 2, wherein the retransmission comprises a first retransmission comprising the first cross-CB coded block and a second retransmission comprising a second cross-CB coded block, and the second cross-CB coded block is generated by encoding, according to the LDPC code, a part of information bits of the first cross-CB coded block.
4. The method according to claim 3, wherein the first cross-CB coded block comprises multiple cross-CB coded blocks, and the part of information bits of the first cross-CB coded block comprises one or more of: bits corresponding to variable nodes of each cross-CB coded block, wherein degrees of the variable nodes are less than a threshold; bits corresponding to ending-most positions of each cross-CB coded block; or bits corresponding to beginning-most positions of each cross-CB coded block.
5. The method according to claim 3 or 4, wherein the transmitting the retransmission comprising the one or more cross-CB coded blocks, comprises: transmitting the first retransmission comprising the first cross-CB coded block; performing a reordering operation in information bits of the first cross-CB coded block; or performing a reordering operation in information bits of the first cross-CB coded block, and performing an interleaving operation in the part of information bits of the first cross-CB coded block; generating the second cross-CB coded block by encoding, according to the LDPC code, the part of information bits of the first cross-CB coded block; and transmitting the second retransmission comprising the second cross-CB coded block.
6. The method according to any one of claims 1-5, wherein the retransmission comprises i th retransmission and j th retransmission, i>j, and a code rate of the i th retransmission satisfies: wherein: represents the code rate of the i th retransmission; K i represents the number of information bits in each CB of the i th retransmission; N i represents code bits of the i th retransmission; K j represents the number of information bits in each CB of the j th retransmission; and N j represents code bits of the j th retransmission.
7. The method according to any one of claims 1-6, wherein the method further comprises: performing an interleaving operation in the part of information bits of the CBs; generating the first cross-CB coded block by encoding, according to the LDPC code, the part of the information bits of the CBs.
8. The method according to any one of claims 1-7, wherein the method further comprises: receiving a negative acknowledgement; and the transmitting the retransmission including the one or more cross-CB coded blocks, comprises: in response to the negative acknowledgement, transmitting the retransmission including the cross-CB coded blocks.
9. The method according to any one of claims 1-8, wherein the method further comprises: transmitting an indication indicating the code rate of the retransmission and/or the code rate of the initial transmission.
10. A communication method, comprising: receiving an initial transmission comprising multiple code blocks (CBs) ; and receiving a retransmission comprising one or more cross-CB coded blocks, wherein the cross-CB coded blocks comprises a first cross-CB coded block, and the first cross-CB coded block is generated by encoding, according to a low density parity check (LDPC) code, a part of information bits of the CBs, wherein a code rate of the retransmission is lower than a code rate of the initial transmission.
11. The method according to claim 10, wherein the method further comprises: decoding the cross-CB coded block of the retransmission, and then decoding the CBs of the initial transmission based on decoded results of the cross-CB coded block.
12. The method according to claim 10 or 11, wherein the part of information bits of the CBs comprises one or more of: bits corresponding to variable nodes of each CB, wherein degrees of the variable nodes are less than a threshold; bits corresponding to ending-most positions of each CB; or bits corresponding to beginning-most positions of each CB.
13. The method according to any one of claims 10-12, wherein the retransmission comprises a first retransmission comprising the first cross-CB coded block and a second retransmission comprising a second cross-CB coded block, and the second cross-CB coded block is generated by encoding, according to the LDPC code, a part of information bits of the first cross-CB coded block.
14. The method according to claim 13, wherein the first cross-CB coded block comprises multiple cross-CB coded blocks, and the part of information bits of the first cross-CB coded block comprises one or more of: bits corresponding to variable nodes of each cross-CB coded block, wherein degrees of the variable nodes are less than a threshold; bits corresponding to ending-most positions of each cross-CB coded block; or bits corresponding to beginning-most positions of each cross-CB coded block.
15. The method according to any one of claims 10-14, wherein the retransmission comprises i th retransmission and j th retransmission, i>j, and a code rate of the i th retransmission satisfies: wherein: represents the code rate of the i th retransmission; K i represents the number of information bits in each CB of the i th retransmission; N i represents code bits of the i th retransmission; K j represents the number of information bits in each CB of the j th retransmission; and N j represents code bits of the j th retransmission.
16. The method according to any one of claims 10-15, wherein before the receiving a retransmission, the method further comprises: transmitting a negative acknowledgement in case of failure to decode the CBs.
17. The method according to any one of claims 10-16, wherein the method further comprises: receiving an indication indicating the code rate of the retransmission and/or the initial transmission.
18. An apparatus comprising a processor configured to enable the apparatus to perform the method of any one of claims 1-17.
19. The apparatus according to claim 18, further comprising a memory for storing processor-executable instructions.
20. The apparatus according to claim 18 or 19, further comprising a communication interface configured to input and/or output at least one of the initial transmission and the retransmission.

Description

METHOD, SYSTEM, AND APPARATUS FOR RETRANSMISSION IN WIRELESS COMMUNICATIONS This application claims priority to United States Patent Application No. 63/530,796, filed to the United States Patent and Trademark Office on August 4, 2023, and entitled “COMMUNICATION SYSTEMS, APPARATUSES, METHODS, AND NON-TRANSITORY COMPUTER-READABLE STORAGE DEVICES EMPLOYING LOW-DENSITY PARITY-CHECK CODING AND RETRANSMISSION WITH INCREMENTAL FREEZING” , which is incorporated herein by reference in its entirety. TECHNICAL FIELD Embodiments of the present application relate to the field of communications, and more specifically, to a communication method and a communication apparatus. For example, the communication method and the communication apparatus may be used for a downlink transmission, or a sidelink transmission, or an uplink transmission. BACKGROUND In a wireless communication, data can be transmitted between communication apparatus, and the data can be represented by a transport block (TB) in a physical layer. Further, the TB can be segmented and encoded by a forward error correction (FEC) code to generate multiple code blocks (CBs) for a transmission. A retransmission is required if the data transmitted in an initial transmission was not decoded successfully. How to efficiently perform retransmission is a problem to be solved. SUMMARY Embodiments of the present application provide a communication method and a communication apparatus. The technical solutions may improve retransmission performance. According to a first aspect, an embodiment of the present application provides a communication method, and the method could be performed by a transmitting apparatus. The transmitting apparatus may be a communication device (for example, a user equipment (UE) , or a base station) , or be a component (e.g., a chip, a circuit, or a processing system) configured in the communication device. The method includes: transmitting an initial transmission including multiple code blocks (CBs) ;  transmitting a retransmission including one or more cross-CB coded blocks, where the cross-CB coded blocks include a first cross-CB coded block, and the first cross-CB coded block is generated by encoding, according to a low density parity check (LDPC) code, a part of information bits of the CBs, wherein a code rate of the retransmission is lower than a code rate of the initial transmission. The first cross-CB coded block can include one or more cross-CB coded blocks. For example, the first cross-CB coded block can be referred to as the first cross-CB coded block set or the first set of cross-CB coded blocks. According to the above technical solution, a cross-CB coded block in a current retransmission can be generated by encoding, according to an LDPC code, a part of information bits of a previous (re) transmission. A receiving apparatus can decode a cross-CB coded block in the current retransmission. If the cross-CB coded blocks are decoded successfully, the part of the information bits can be considered as frozen bits (i.e., be known at decoders) , which allows the rest of information bits in the previous (re) transmission can be decoded with a lower code rate. Compared to traditional HARQ IR that requires decoding a long codeword, the above technical solution can offer lower decoding complexity by decoding multiple short codewords, and improve retransmission performance. In a possible design, the part of information bits of the CBs includes one or more of: bits corresponding to variable nodes of each CB, where degrees of the variable nodes are less than a threshold; bits corresponding to ending-most positions of each CB; or bits corresponding to beginning-most positions of each CB. According to the above technical solution, some specific information bits can be retransmitted by the cross-CB coded block. For example, information bits corresponding to variable nodes with higher degrees are more likely be decoded successfully since they receive more information from adjacent check nodes. So, information bits corresponding to variable nodes with lower degrees can be retransmitted. In a possible design, where the retransmission includes a first retransmission including the first cross-CB coded block and a second retransmission including a second cross-CB coded block, and the second cross-CB coded block is generated by encoding, according to an LDPC code, part of information bits of the first cross-CB coded block. According to the above technical solution, for multiple retransmissions, a cross-CB coded block in current retransmission can be generated by encoding, according to an LDPC code, a part of information bits of previous retransmission, and a receiving apparatus can decode a cross-CB coded block in current retransmission. In a possible design, where the first cross-CB coded block includes multiple cross-CB coded blocks, the part of information bits of the first cross-CB coded block includes one or more of: bits corresponding to variable