US-12621081-B2 - Methods and procedures for polar encoding and decoding with low latency

US12621081B2US 12621081 B2US12621081 B2US 12621081B2US-12621081-B2

Abstract

A polar code may be initially divided into multiple polar component codes where the features of these component codes, such as the number of component codes and the size of the component codes, are determined based on parameters such as the number of available timing units within a transmission interval, interleaving depth, and decoder capability. For each selected component code, the order of code bit generation and their indexes may be determined. The determined indexes may be assigned into different, unique groups according to the order of code bit generation. An interleaving operation may be configured and then executed according to the determined index grouping. In the transmission phase, the code bits may be transmitted based on the identified order of the bit generation in the component polar codes, such as the determined index grouping.

Inventors

Sungkwon Hong
Onur Sahin

Assignees

INTERDIGITAL PATENT HOLDINGS, INC.

Dates

Publication Date: 20260505
Application Date: 20231218

Claims (16)

1 . A method comprising: decomposing a code into a plurality of component codes, wherein each of the plurality of component codes has a reduced block length compared to the code, wherein the plurality of component codes includes a first component code and a second component code; generating a group of code bits by grouping a code bit of the first component code with a code bit of the second component code based on a respective index of the code bit of the first component code and of the code bit of the second component code; interleaving the group of code bits; and transmitting a transmission that includes the group of code bits to a receiver.
2 . The method of claim 1 , further comprising: receiving capability information of the receiver; determining time interval information based on the capability information of the receiver; and sending control information to the receiver prior to transmitting the transmission, wherein the control information includes time interval information.
3 . The method of claim 1 , wherein the method is performed by a wireless transmit receive unit (WTRU) or a base station.
4 . The method of claim 1 , wherein the code bit of the first component code and the code bit of the second component code have a same index.
5 . The method of claim 1 , wherein the grouping is further based on a timing order of code bit generations of each component code.
6 . The method of claim 1 , wherein the reduced block length of each of the plurality of component codes is the same.
7 . The method of claim 1 , wherein the interleaving of the group of code bits comprises interleaving all code bits within the group of code bits or interleaving the group of code bits with one or more code bits in at least one other group of code bits.
8 . The method of claim 1 , wherein the interleaving of the group of code bits comprises interleaving the group of code bits at a group level with at least one other group of code bits.
9 . A device comprising: a transceiver and a processor, the transceiver and processor configured to decompose a code into a plurality of component codes, wherein each of the plurality of component codes has a reduced block length compared to the code, wherein the plurality of component codes includes a first component code and a second component code; the transceiver and processor configured to generate a group of code bits by grouping a code bit of the first component code with a code bit of the second component code based on a respective index of the code bit of the first component code and of the code bit of the second component code; the transceiver and processor configured to interleave the group of code bits; and the transceiver and processor configured to transmit a transmission that includes the group of code bits to a receiver.
10 . The device of claim 9 , wherein: the transceiver and processor configured to receive capability information of the receiver; the transceiver and processor configured to determine time interval information based on the capability information of the receiver; and the transceiver and processor configured to send control information to the receiver prior to transmitting the transmission, wherein the control information includes time interval information.
11 . The device of claim 9 , wherein the device is a wireless transmit receive unit (WTRU) or a base station.
12 . The device of claim 9 , wherein the code bit of the first component code and the code bit of the second component code have a same index.
13 . The device of claim 9 , wherein the grouping is further based on a timing order of code bit generations of each component code.
14 . The device of claim 9 , wherein the reduced block length of each of the plurality of component codes is the same.
15 . The device of claim 9 , wherein the interleaving of the group of code bits comprises interleaving all code bits within the group of code bits or interleaving the group of code bits with one or more code bits in at least one other group of code bits.
16 . The device of claim 9 , wherein the interleaving of the group of code bits comprises interleaving the group of code bits at a group level with at least one other group of code bits.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 17/310,249 filed Jul. 27, 2021, which will issue as U.S. Pat. No. 11,848,778 on Dec. 19, 2023, which is the U.S. National Stage, under 35 U.S.C. § 371, of International Application No. PCT/US2020/015714 filed on Jan. 29, 2020 which claims the benefit of U.S. Provisional Application No. 62/798,208, filed Jan. 29, 2019, the contents of which are hereby incorporated herein by reference. BACKGROUND Polar codes are the first channel code type analytically proven to be capacity achieving. Polar codes show comparable performance to conventional LDPC code or turbo code with low or no error floor when aided by the embedded CRC, particularly for small to medium block lengths. Polar codes with successive cancellation decoding requires relatively low encoding and decoding complexities. However, the decoding complexity and latency may increase in proportion to the list-size when the CRC-aided list decoding is adopted as well as the block-length of the codeword. The complexity and latency increase becomes a central issue particularly in medium to large block-lengths, and limits the adoption of polar codes for high throughput regime including 5G NR eMBB data rates (˜20 Gbps) and above. SUMMARY A polar code may be initially divided into multiple polar component codes where the features of these component codes, such as the number of component codes and the size of the component codes, are determined based on parameters such as the number of available timing units within a transmission interval, interleaving depth, and decoder capability. For each selected component code, the order of code bit generation and their indexes may be determined. The determined indexes may be assigned into different, unique groups according to the order of code bit generation. An interleaving operation may be configured and then executed according to the determined index grouping. In the transmission phase, the code bits may be transmitted based on the identified order of the bit generation in the component polar codes, such as the determined index grouping. In the receiver, the decoder may start its decoding process of the received channel symbols utilizing the order of the transmission information made available to itself a priori, and therefore the decoding process may star before receiving all channel symbols. BRIEF DESCRIPTION OF THE DRAWINGS A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein: FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented; FIG. 1B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment; FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment; FIG. 1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment; FIG. 2 is a diagram that illustrates an example polar encoder with the code word block-length N=8; FIG. 3 is a diagram that illustrates an example of LLR message passing for BP decoding; FIG. 4 is a diagram that illustrates an example method for ordered transmission of polar code; FIG. 5 is four diagrams that illustrate an example of polar code decomposition into four possible component polar codes; FIG. 6 are three diagrams that illustrate sequential encoding steps and coded bit generations at each timing step for a given component polar code of length N′=8; FIG. 7 is a flow chart that illustrates an example method of identifying a code bit order based on component polar codes with length N′=2n′; FIG. 8 is a diagram that illustrates an example of ordered grouping and group interleaving; FIG. 9 is a flow chart that illustrates an example of a NR multiplexing chain modified with an interleaving step 904 inserted; FIG. 10 is a diagram that illustrates an example of timing relation in early start decoding; FIG. 11 is a flow chart illustrating an example decoding procedure; FIG. 12 is graph illustrating an example of a comparison of simulated block error performance between example procedures for conventional and early start decoding; FIG. 13 is graph illustrating an example of a comparison of simulated timing steps between example procedures for conventional and early start BP decoding; and FIG. 14 is graph illustrating an example of is graph illustrating an example of a comparison of simulated timing steps between example procedures for conventional and ear