Asynchronous MIMO-OFDM Massive Unsourced Random Access with Codeword Collisions

Fuente: arXiv
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Auteurs principaux: Li, Tianya, Wu, Yongpeng, Gao, Junyuan, Zhang, Wenjun, Xia, Xiang-Gen, Ng, Derrick Wing Kwan, Xiao, Chengshan
Format: Preprint
Publié: 2024
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author Li, Tianya
Wu, Yongpeng
Gao, Junyuan
Zhang, Wenjun
Xia, Xiang-Gen
Ng, Derrick Wing Kwan
Xiao, Chengshan
author_facet Li, Tianya
Wu, Yongpeng
Gao, Junyuan
Zhang, Wenjun
Xia, Xiang-Gen
Ng, Derrick Wing Kwan
Xiao, Chengshan
contents This paper investigates asynchronous multiple-input multiple-output (MIMO) massive unsourced random access (URA) in an orthogonal frequency division multiplexing (OFDM) system over frequency-selective fading channels, with the presence of both timing and carrier frequency offsets (TO and CFO) and non-negligible codeword collisions. The proposed coding framework segregates the data into two components, namely, preamble and coding parts, with the former being tree-coded and the latter LDPC-coded. By leveraging the dual sparsity of the equivalent channel across both codeword and delay domains (CD and DD), we develop a message-passing-based sparse Bayesian learning algorithm, combined with belief propagation and mean field, to iteratively estimate DD channel responses, TO, and delay profiles. Furthermore, by jointly leveraging the observations among multiple slots, we establish a novel graph-based algorithm to iteratively separate the superimposed channels and compensate for the phase rotations. Additionally, the proposed algorithm is applied to the flat fading scenario to estimate both TO and CFO, where the channel and offset estimation is enhanced by leveraging the geometric characteristics of the signal constellation. Extensive simulations reveal that the proposed algorithm achieves superior performance and substantial complexity reduction in both channel and offset estimation compared to the codebook enlarging-based counterparts, and enhanced data recovery performances compared to state-of-the-art URA schemes.
format Preprint
id arxiv_https___arxiv_org_abs_2405_11883
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Asynchronous MIMO-OFDM Massive Unsourced Random Access with Codeword Collisions
Li, Tianya
Wu, Yongpeng
Gao, Junyuan
Zhang, Wenjun
Xia, Xiang-Gen
Ng, Derrick Wing Kwan
Xiao, Chengshan
Information Theory
Signal Processing
This paper investigates asynchronous multiple-input multiple-output (MIMO) massive unsourced random access (URA) in an orthogonal frequency division multiplexing (OFDM) system over frequency-selective fading channels, with the presence of both timing and carrier frequency offsets (TO and CFO) and non-negligible codeword collisions. The proposed coding framework segregates the data into two components, namely, preamble and coding parts, with the former being tree-coded and the latter LDPC-coded. By leveraging the dual sparsity of the equivalent channel across both codeword and delay domains (CD and DD), we develop a message-passing-based sparse Bayesian learning algorithm, combined with belief propagation and mean field, to iteratively estimate DD channel responses, TO, and delay profiles. Furthermore, by jointly leveraging the observations among multiple slots, we establish a novel graph-based algorithm to iteratively separate the superimposed channels and compensate for the phase rotations. Additionally, the proposed algorithm is applied to the flat fading scenario to estimate both TO and CFO, where the channel and offset estimation is enhanced by leveraging the geometric characteristics of the signal constellation. Extensive simulations reveal that the proposed algorithm achieves superior performance and substantial complexity reduction in both channel and offset estimation compared to the codebook enlarging-based counterparts, and enhanced data recovery performances compared to state-of-the-art URA schemes.
title Asynchronous MIMO-OFDM Massive Unsourced Random Access with Codeword Collisions
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2405.11883