Near-Optimal Detection of Zak-OTFS Signals

Jesbin, F and Chockalingam, A (2024) Near-Optimal Detection of Zak-OTFS Signals. In: 59th Annual IEEE International Conference on Communications, ICC 2024, 9 June 2024through 13 June 2024, Denver, pp. 4476-4481.

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Abstract

Orthogonal time frequency space (OTFS) modulation is emerging as a promising alternative to currently deployed multicarrier modulation schemes, particularly in high-Doppler wireless channels. The multicarrier (MC) version of OTFS (MC-OTFS) has dominated the OTFS research literature so far due to its compatibility with the prevailing MC modulation schemes. Recently, Zak transform based OTFS (Zak-OTFS) has gained prominence on account of its superior performance and low complexity. However, unlike in its MC counterpart, the transceiver signal processing aspects like equalization/detection and channel estimation in Zak-OTFS remain vastly unexplored. In this paper, we present an early investigation of low-complexity detection algorithms for Zak-OTFS that can scale efficiently for large frame sizes and achieve near-optimal performance. For this, we resort to efficient local search algorithms, namely, likelihood ascent search (LAS) and reactive tabu search (RTS) algorithms, that scale well for large dimensions. To assess the closeness of the performance of these algorithms to the optimum maximum likelihood (ML) performance, we obtain a lower bound on ML performance via RTS simulation using the transmit vector as the initial vector and defining a suitable neighborhood. Our simulation results indicate that while the performance of the popularly known minimum mean square error (MMSE) and message passing (MP) algorithms are far from the ML performance bound, LAS and RTS algorithms initialized with MMSE solution achieve close to ML performance bound within about 1 dB at a bit error rate of 10-5 © 2024 IEEE.

Item Type:	Conference Paper
Publication:	IEEE International Conference on Communications
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Channel estimation; Health risks; Image thinning; Maximum likelihood estimation; Risk assessment; Signal modulation; Tabu search, Delay-dopple domain; Doppler; Likelihood ascent search; Low bound; Ma ximum likelihoods; Maximum likelihood low bound; Maximum-likelihood; Message passing detection; Message-passing; Minimum mean square error detections; Multicarrier-orthogonal time frequency space; Multicarriers; Orthogonal time frequency space modulation; Reactive Tabu search; Time-frequency space; Zak transform based OTFS, Multicarrier modulation
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	25 Sep 2024 10:23
Last Modified:	25 Sep 2024 10:23
URI:	http://eprints.iisc.ac.in/id/eprint/86289

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