US-12628038-B2 - Method for transmitting signal on basis of HARQ by using PC polar code in wireless communication system, and apparatus therefor

US12628038B2US 12628038 B2US12628038 B2US 12628038B2US-12628038-B2

Abstract

A method by which a first wireless apparatus transmits a signal on the basis of a hybrid automatic repeat request (HARQ) by using a parity check (PC) polar code in a wireless communication system, according to one embodiment of the present specification, comprises the steps of: generating a first codeword on the basis of a first PC polar code; transmitting the first codeword; generating a second codeword on the basis of a second PC polar code; and transmitting the second codeword.

Inventors

Bonghoe Kim
Jongwoong Shin

Assignees

LG ELECTRONICS INC.

Dates

Publication Date: 20260512
Application Date: 20210705

Claims (15)

1 . A method for transmitting a signal based on Hybrid Automatic Repeat reQuest (HARQ) using a parity check (PC) polar code by a first wireless device in a wireless communication system, the method comprising: generating a first codeword based on a first PC polar code, wherein the first codeword is generated based on one or more first bit channel indices among bit channel indices of the first PC polar code; transmitting the first codeword; generating a second codeword based on a second PC polar code, wherein the second codeword is generated based on one or more second bit channel indices among bit channel indices of the second PC polar code; and transmitting the second codeword, wherein the transmission of the second codeword is related to retransmission of the first codeword, wherein the one or more first bit channel indices are allocated to a data block and at least one first parity check (PC) bit, wherein the one or more second bit channel indices are allocated to the data block and at least one second parity check (PC) bit, wherein the at least one second PC bit includes the at least one first PC bit, wherein the one or more second bit channel indices are based on specific bit channel indices determined based on an order of a reliability related to the second PC polar code, and wherein, based on the specific bit channel indices including at least one third bit channel index belonging to a lower polar subcode of the second PC polar code: 1) The one or more second bit channel indices include at least one fourth bit channel index, 2) the at least one fourth bit channel index is determined in a range excluding the specific bit channel indices among bit channel indices belonging to an upper polar subcode of the second PC polar code, 3) The at least one fourth bit channel index is allocated to a specific bit value related to the at least one third bit channel index, 4) The specific bit value is related to at least one of i) the at least one second PC bit or ii) the data block, and 5) A bit value of the third bit channel index related to the at least one second PC bit among the at least one third bit channel index is configured as 0.
2 . The method of claim 1 , wherein the at least one fourth bit channel index is determined based on i) the order of the reliability and ii) a number of the at least one third bit channel index.
3 . The method of claim 1 , wherein the specific bit channel indices include i) one or more first specific bit channel indices determined based on a size of the data block and the order of the reliability and ii) one or more second specific bit channel indices determined based on a number of the at least one second PC bit and the order of the reliability.
4 . The method of claim 3 , wherein, based on the one or more third bit channel indices being included in the one or more first specific bit channel indices, among the one or more second specific bit channel indices, a bit channel index belonging to the upper polar subcode of the second PC polar code is changed to the first specific bit channel index.
5 . The method of claim 4 , wherein the fourth bit channel index based on a number of the second specific bit channel index changed to the first specific bit channel index is allocated to the at least one second PC bit.
6 . The method of claim 1 , wherein the order of the reliability is based on a descending order of values indicating a reliability related to the bit channel indices of the second PC polar code.
7 . The method of claim 1 , wherein the one or more second bit channel indices i) include the one or more first bit channel indices, or ii) include bit channel indices obtained by adding a first specific value to the one or more first bit channel indices.
8 . The method of claim 1 , wherein, based on a size of the data block being greater than or equal to a preconfigured value, the at least one second PC bit further includes one or more additional PC bits in addition to the at least one first PC bit.
9 . The method of claim 8 , wherein, based on the at least one second PC bit including the one or more additional PC bits, the one or more second bit channel indices include at least one fifth bit channel indices, wherein the at least one fifth bit channel indices is determined according to the order of the reliability in a range excluding the specific bit channel indices and the at least one fourth bit channel index among all bit channel indices of the second PC polar code.
10 . The method of claim 1 , wherein when the specific bit value relates only to the at least one second PC bit, a size of the second PC polar code is the same as a size of the first PC polar code.
11 . A first wireless device transmitting a signal based on Hybrid Automatic Repeat reQuest (HARQ) using a parity check (PC) polar code in a wireless communication system, the first wireless device comprising: one or more transceivers; one or more processors controlling the one or more transceivers; and one or more memories operably connected to the one or more processors, and storing instructions that configure the one or more processors to perform operations when being executed by the one or more processors, wherein the operations includes: generating a first codeword based on a first PC polar code, wherein the first codeword is generated based on one or more first bit channel indices among bit channel indices of the first PC polar code; transmitting the first codeword; generating a second codeword based on a second PC polar code, wherein the second codeword is generated based on one or more second bit channel indices among bit channel indices of the second PC polar code; and transmitting the second codeword, wherein the transmission of the second codeword is related to retransmission of the first codeword, wherein the one or more first bit channel indices are allocated to a data block and at least one first parity check (PC) bit, wherein the one or more second bit channel indices are allocated to the data block and at least one second parity check (PC) bit, wherein the at least one second PC bit includes the at least one first PC bit, wherein the one or more second bit channel indices are based on specific bit channel indices determined based on an order of a reliability related to the second PC polar code, and wherein, based on the specific bit channel indices including at least one third bit channel index belonging to a lower polar subcode of the second PC polar code: 1) The one or more second bit channel indices include at least one fourth bit channel index, 2) the at least one fourth bit channel index is determined in a range excluding the specific bit channel indices among bit channel indices belonging to an upper polar subcode of the second PC polar code, 3) The at least one fourth bit channel index is allocated to a specific bit value related to the at least one third bit channel index, 4) The specific bit value is related to at least one of i) the at least one second PC bit or ii) the data block, and 5) A bit value of the third bit channel index related to the at least one second PC bit among the at least one third bit channel index is configured as 0.
12 . The device of claim 11 , wherein the first wireless device is based on a user equipment (UE) or a base station (BS).
13 . The device of claim 11 , wherein the one or more second bit channel indices i) include the one or more first bit channel indices, or ii) include bit channel indices obtained by adding a first specific value to the one or more first bit channel indices.
14 . The device of claim 11 , wherein the specific bit channel indices include i) one or more first specific bit channel indices determined based on a size of the data block and the order of the reliability and ii) one or more second specific bit channel indices determined based on a number of the at least one second PC bit and the order of the reliability.
15 . One or more non-transitory computer-readable medium storing one or more instructions, wherein the one or more instructions configure the one or more processors to perform operations when being executed by the one or more processors, wherein the operations includes: generating a first codeword based on a first parity check (PC) polar code, wherein the first codeword is generated based on one or more first bit channel indices among bit channel indices of the first PC polar code; transmitting the first codeword; generating a second codeword based on a second parity check (PC) polar code, wherein the second codeword is generated based on one or more second bit channel indices among bit channel indices of the second PC polar code; and transmitting the second codeword, wherein the transmission of the second codeword is related to retransmission of the first codeword, wherein the one or more first bit channel indices are allocated to a data block and at least one first parity check (PC) bit, wherein the one or more second bit channel indices are allocated to the data block and at least one second parity check (PC) bit, wherein the at least one second PC bit includes the at least one first PC bit, wherein the one or more second bit channel indices are based on specific bit channel indices determined based on an order of a reliability related to the second PC polar code, and wherein, based on the specific bit channel indices including at least one third bit channel index belonging to a lower polar subcode of the second PC polar code: 1) The one or more second bit channel indices include at least one fourth bit channel index, 2) the at least one fourth bit channel index is determined in a range excluding the specific bit channel indices among bit channel indices belonging to an upper polar subcode of the second PC polar code, 3) The at least one fourth bit channel index is allocated to a specific bit value related to the at least one third bit channel index, 4) the specific bit value is related to at least one of i) the at least one second PC bit or ii) the data block, and 5) A bit value of the third bit channel index related to the at least one second PC bit among the at least one third bit channel index is configured as 0.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a National Stage application under 35 U.S.C. § 371 of International Application No. PCT/KR2021/095073, filed on Jul. 5, 2021. The disclosure of the prior application is incorporated by reference in its entirety. SUMMARY The present disclosure relates to a method for transmitting a signal based on HARQ using a PC polar code in a wireless communication system, and an apparatus therefor. BACKGROUND Mobile communication systems have been developed to provide voice services, while ensuring activity of users. However, coverage of the mobile communication systems has been extended up to data services, as well as voice service, and currently, an explosive increase in traffic has caused shortage of resources, and since users expect relatively high speed services, an advanced mobile communication system is required. Requirements of a next-generation mobile communication system include accommodation of explosive data traffic, a significant increase in a transfer rate per user, accommodation of considerably increased number of connection devices, very low end-to-end latency, and high energy efficiency. To this end, there have been researched various technologies such as dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband, device networking, and the like. DISCLOSURE Technical Problem The present disclosure proposes a method for transmitting a signal based on HARQ, using parity check (PC) polar code and an apparatus therefor. The conventional method (e.g. NR standard) only uses PC polar code for transmission of control data and does not support HARQ through the PC polar code. In the 6G system, HARQ needs to be supported to utilize the PC polar code for data transmission. In the case of the Incremental Freezing (IF) HARQ method, the bit channel index allocated to the data bit changes. Because of this, combining the codeword received based on retransmission and the codeword received based on first transmission is possible after decoding the codeword received based on the retransmission. In the case of the Incremental Redundancy (IR) HARQ method, when a retransmitted codeword is received, combining operation is possible without decoding the codeword. Therefore, IF HARQ does not improve system performance significantly compared to IR HARQ. Meanwhile, in order to support IR HARQ, the characteristic that the codeword generated for first transmission must be included in the codeword generated for the retransmission must be satisfied. In this regard, the size of the polar code (mother code size) for the retransmission may be different from the size of the polar code used for first transmission. In this case, since the data bits are allocated to bit channel indices determined in an order according to the reliability of the polar encoder, a problem may occur in which the codeword generated for first transmission is not included in the codeword generated for the retransmission. The present disclosure proposes a method to solve the above-mentioned problems in supporting IR HARQ based on polar code. Additionally, in the case of PC polar code, a PC bit is included in the codeword in addition to the data bit. Even if a retransmission codeword is generated to include the coded bits of the initial transmission codeword for combining, it is necessary to generate a retransmission codeword by treating the PC bit and data bit differently in terms of operational efficiency. The present disclosure proposes a method of generating a retransmission codeword by considering the difference between data bits and PC bits when supporting IR HARQ based on PC polar codes. The technical objects of the present disclosure are not limited to the aforementioned technical objects, and other technical objects, which are not mentioned above, will be apparently appreciated by a person having ordinary skill in the art from the following description. A method for transmitting a signal based on Hybrid Automatic Repeat reQuest (HARQ) using a parity check (PC) polar code by a first wireless device in a wireless communication system according to an embodiment of the present disclosure, the method comprises generating a first codeword based on a first PC polar code, transmitting the first codeword, generating a second codeword based on a second PC polar code, and transmitting the second codeword. The first codeword is generated based on one or more first bit channel indices among bit channel indices of the first PC polar code, and the second codeword is generated based on one or more second bit channel indices among bit channel indices of the second PC polar code. The transmission of the second codeword may be related to retransmission of the first codeword. The one or more first bit channel indices may be allocated to a data block and at least one first parity check (PC) bit. The one or more second bit channel indices may