Gaussian and Fading Multiple Access Using Linear Physical-Layer Network Coding
This paper concerns with efficient communication over Gaussian and fading multiple-access channels (MACs). Existing orthogonal multiple-access (OMA) and power-domain nonorthogonal-OMA (NOMA) cannot achieve all rate-tuples in the MAC capacity region. Meanwhile, code-domain NOMA schemes usually requir...
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Published in | IEEE transactions on wireless communications Vol. 22; no. 5; pp. 3099 - 3113 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
New York
IEEE
01.05.2023
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Subjects | |
Online Access | Get full text |
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Summary: | This paper concerns with efficient communication over Gaussian and fading multiple-access channels (MACs). Existing orthogonal multiple-access (OMA) and power-domain nonorthogonal-OMA (NOMA) cannot achieve all rate-tuples in the MAC capacity region. Meanwhile, code-domain NOMA schemes usually require big-loop receiver-iterations for multi-user decoding, which is subject to high implementation cost and latency. This paper studies a linear physical-layer network coding multiple access (LPNC-MA) scheme that is capable of achieving any rate-tuples in the MAC capacity region without receiver iterations. For deterministic Gaussian MACs with <inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula> users, we propose to utilize <inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula>-ary irregular repeat accumulate (IRA) codes over finite integer fields/rings and <inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula>-ary pulse amplitude modulation (<inline-formula> <tex-math notation="LaTeX">q </tex-math></inline-formula>-PAM) as the underlying coded-modulation. The receiver sequentially computes <inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula> network coded (NC) messages of the <inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula> users. All users' messages are then recovered by solving the computed <inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula> NC messages via the inverse of the NC coefficient matrix. A joint nested code construction and extrinsic information transfer (EXIT) chart based code optimization method is developed, yielding near-capacity performance (within 0.7 and 1.1 dB the capacity limits for two and three users respectively). For fading MAC, we study the symmetric rate of LPNC-MA, and propose a pragmatic method for identifying the mutual information (MI) maximizing network coding coefficient matrix. Numerical results demonstrate that the frame error rate (FER) of the optimized LPNC-MA is within a fraction of dB the outage probability of fading MAC capacity. LPNC-MA remarkably outperforms NOMA-SIC and IDMA while avoiding the big-loop receiver iteration. |
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ISSN: | 1536-1276 1558-2248 |
DOI: | 10.1109/TWC.2022.3216002 |