Massive Grant-free OFDMA with Timing and Frequency Offsets

Sun, Gangle, Li, Yining, Yi, Xinping ORCID: 0000-0001-5163-2364, Wang, Wenjin, Gao, Xiqi, Wang, Lei, Wei, Fan and Chen, Yan
(2021) Massive Grant-free OFDMA with Timing and Frequency Offsets. IEEE Transactions on Wireless Communications, 21 (5). pp. 3365-3380.

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In the massive grant-free orthogonal frequency division multiple access (OFDMA), the timing and frequency offsets between users impose new challenges on joint active user detection (AUD) and channel estimation (CE) for the subsequent data recovery. In the asynchronous OFDMA, the timing and frequency offset effects can be modeled as the phase-shifting on the pilot matrix. As such, by constructing the measurement matrix with timing and frequency offsets, the joint estimation problem can be formulated as a multiple measurement vector (MMV) recovery problem with structured sparsity. However, such structured sparsity cannot be tackled by the existing compressed sensing (CS) techniques. To address this issue, we develop an efficient structured generalized approximate message passing (S-GAMP) algorithm, which includes the parallel AMP-MMV algorithm as a particular case. To deal with the high dimensionality of the measurement matrix, we propose the dynamic S-GAMP algorithm with a dynamic measurement matrix to reduce the computational complexity. Simulation results confirm the superiority of the proposed algorithms in grant-free OFDMA with both timing and frequency offsets.

Item Type: Article
Uncontrolled Keywords: OFDM, Timing, Approximation algorithms, Heuristic algorithms, Estimation, Frequency estimation, Wireless communication, Grant-free, mMTC, channel estimation, active user detection, message passing
Divisions: Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science
Depositing User: Symplectic Admin
Date Deposited: 28 Oct 2021 07:27
Last Modified: 16 Mar 2024 01:14
DOI: 10.1109/TWC.2021.3121066
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