Windowed Joint Detection and Decoding with IR-HARQ for Asynchronous SCMA Systems

Mengsheng Guan; Min Zhu; Baoming Bai

doi:10.3390/e25060930

Windowed Joint Detection and Decoding with IR-HARQ for Asynchronous SCMA Systems

Entropy (Basel). 2023 Jun 13;25(6):930. doi: 10.3390/e25060930.

Authors

Mengsheng Guan¹, Min Zhu^{1

2}, Baoming Bai¹

Affiliations

¹ The State Key Laboratory of Integrated Services Networks, Xidian University, Xi'an 710071, China.
² Science and Technology on Communication Networks Laboratory, Shijiazhuang 050081, China.

Abstract

To improve the decoding performance of asynchronous sparse code multiple access (SCMA) systems over additive white Gaussian noise (AWGN) channels, this paper proposes a novel windowed joint detection and decoding algorithm for a rate-compatible (RC), LDPC code-based, incremental redundancy (IR) hybrid automatic repeat quest (HARQ) scheme. Since incremental decoding can exchange information iteratively with the detections made at previous consecutive time units, we propose a windowed joint detection and decoding algorithm. The extrinsic information exchanging process is performed between the decoders and the previous w detectors at different consecutive time units. Simulation results show that the sliding-window IR-HARQ scheme for the SCMA system outperforms the original IR-HARQ scheme with a joint detection and decoding algorithm. The throughput of the SCMA system with the proposed IR-HARQ scheme is also improved.

Keywords: IR-HARQ; RC-LDPC; SCMA; windowed joint detection and decoding.

Grants and funding

This work was supported in part by the National Key R&D Program of China under Grant 2021YFB2900500 and in part by the National Natural Science Foundation of China under Grants 62271380 and 62171356.