Single Sparse Graph Enhanced Expectation Propagation Algorithm Design for Uplink MIMO-SCMA

Fuente: arXiv
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Main Authors: Luo, Qu, Zhu, Jing, Chen, Gaojie, Xiao, Pei, Tafazolli, Rahim
Format: Preprint
Published: 2025
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author Luo, Qu
Zhu, Jing
Chen, Gaojie
Xiao, Pei
Tafazolli, Rahim
author_facet Luo, Qu
Zhu, Jing
Chen, Gaojie
Xiao, Pei
Tafazolli, Rahim
contents Sparse code multiple access (SCMA) and multiple input multiple output (MIMO) are considered as two efficient techniques to provide both massive connectivity and high spectrum efficiency for future machine-type wireless networks. This paper proposes a single sparse graph (SSG) enhanced expectation propagation algorithm (EPA) receiver, referred to as SSG-EPA, for uplink MIMO-SCMA systems. Firstly, we reformulate the sparse codebook mapping process using a linear encoding model, which transforms the variable nodes (VNs) of SCMA from symbol-level to bit-level VNs. Such transformation facilitates the integration of the VNs of SCMA and low-density parity-check (LDPC), thereby emerging the SCMA and LDPC graphs into a SSG. Subsequently, to further reduce the detection complexity, the message propagation between SCMA VNs and function nodes (FNs) are designed based on EPA principles. Different from the existing iterative detection and decoding (IDD) structure, the proposed EPA-SSG allows a simultaneously detection and decoding at each iteration, and eliminates the use of interleavers, de-interleavers, symbol-to-bit, and bit-to-symbol LLR transformations. Simulation results show that the proposed SSG-EPA achieves better error rate performance compared to the state-of-the-art schemes.
format Preprint
id arxiv_https___arxiv_org_abs_2503_13681
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Single Sparse Graph Enhanced Expectation Propagation Algorithm Design for Uplink MIMO-SCMA
Luo, Qu
Zhu, Jing
Chen, Gaojie
Xiao, Pei
Tafazolli, Rahim
Signal Processing
Sparse code multiple access (SCMA) and multiple input multiple output (MIMO) are considered as two efficient techniques to provide both massive connectivity and high spectrum efficiency for future machine-type wireless networks. This paper proposes a single sparse graph (SSG) enhanced expectation propagation algorithm (EPA) receiver, referred to as SSG-EPA, for uplink MIMO-SCMA systems. Firstly, we reformulate the sparse codebook mapping process using a linear encoding model, which transforms the variable nodes (VNs) of SCMA from symbol-level to bit-level VNs. Such transformation facilitates the integration of the VNs of SCMA and low-density parity-check (LDPC), thereby emerging the SCMA and LDPC graphs into a SSG. Subsequently, to further reduce the detection complexity, the message propagation between SCMA VNs and function nodes (FNs) are designed based on EPA principles. Different from the existing iterative detection and decoding (IDD) structure, the proposed EPA-SSG allows a simultaneously detection and decoding at each iteration, and eliminates the use of interleavers, de-interleavers, symbol-to-bit, and bit-to-symbol LLR transformations. Simulation results show that the proposed SSG-EPA achieves better error rate performance compared to the state-of-the-art schemes.
title Single Sparse Graph Enhanced Expectation Propagation Algorithm Design for Uplink MIMO-SCMA
topic Signal Processing
url https://arxiv.org/abs/2503.13681