CRC-Aided Logarithmic Stack Decoding of Polar Codes for Ultra Reliable Low Latency Communication in 3GPP New Radio

Luping Xiang,Lajos Hanzo,Zeynep B Kaykac Egilmez,Robert G Maunder

doi:10.1109/access.2019.2901596

Luping Xiang, Lajos Hanzo + Show 2 more

Open Access

https://doi.org/10.1109/access.2019.2901596

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Abstract

This paper provides a detailed tutorial on the Cyclic Redundancy Check (CRC)-aided logarithmic successive cancellation stack (Log-SCS) algorithm. We apply these algorithms for the ultrareliable decoding of polar codes, which has relevance for the control channels of the ultra-reliable low latency communication version of the third generation partnership project (3GPP) New Radio (NR). During the exploitation of the CRC codes to improve the error correction performance, we propose a novel technique which limits the number of CRC checks performed, in order to maintain a consistent error detection performance. In addition, we propose a pair of techniques for further improving the performance of the Log-SCS polar decoder. We demonstrate that the proposed S = 128 Improved Log-SCS decoder achieves a similar error correction capability as a logarithmic successive cancellation list (Log-SCL) decoder having a list size of L = 128 across the full range of block lengths supported by the 3GPP NR physical uplink control channel. This is achieved without increasing its memory requirement, while dramatically reducing its complexity, which becomes up to seven times lower than that of a L = 8 Log-SCL decoder.

Highlights

We demonstrate that the application of the logarithmic successive cancellation stack (Log-Successive Cancellation Stack (SCS)) decoder to the 3GPP New Radio (NR) polar code of Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH) offers as much as 0.5 dB improved error correction performance, compared to the previous SCS algorithm using the same stack size of S = 8
In this paper, we have provided a detailed tutorial on the application of the Log-SCS algorithm to the 3GPP NR uplink polar code
We have demonstrated that the Log-SCS algorithm improves upon the BLER of the state-of-the-art LogSCL polar decoder, while reducing the complexity

Summary

INTRODUCTION

Owing to their near-capacity error correction performance at short block lengths, polar codes [1], [2] have been selected for protecting the control channels of the Third Generation Partnership Project (3GPP) New Radio (NR) candidate for fifth generation (5G) mobile communications [3]. During the exploitation of the CRC codes to improve the error correction performance, we propose a novel technique for limiting the number of CRC checks performed in stack decoding, in order to maintain a consistent error detection performance In this application, we demonstrate that the application of the Log-SCS decoder to the 3GPP NR polar code of PUCCH and PUSCH offers as much as 0.5 dB improved error correction performance, compared to the previous SCS algorithm using the same stack size of S = 8. This is in contrast to the CRC-aided SCS algorithm of [28], which continues considering successive CRCs indefinitely, until a pass is found, resulting in a high prevalence of undetected block errors

FROZEN BIT INSERTION AND REMOVAL

RATE MATCHING AND DEMATCHING

19: Remove the entry in the stack having the worst

Findings

CONCLUSIONS