Low-Complexity Oversampled OTFS Receivers With Reduced Overhead

Orthogonal Time Frequency Space (OTFS) modulation enables reliable communication in fast time-varying, frequency-selective channels. It is a delay-Doppler (DD) domain modulation that models the information symbols and the channel in the DD domain. This paper considers a pulse-shaped OTFS system with...

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Main Authors: Narendra Deconda, Srikrishna Bhashyam, Nambi Seshadri, R. David Koilpillai
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of the Communications Society
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Online Access:https://ieeexplore.ieee.org/document/10879026/
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author Narendra Deconda
Srikrishna Bhashyam
Nambi Seshadri
R. David Koilpillai
author_facet Narendra Deconda
Srikrishna Bhashyam
Nambi Seshadri
R. David Koilpillai
author_sort Narendra Deconda
collection DOAJ
description Orthogonal Time Frequency Space (OTFS) modulation enables reliable communication in fast time-varying, frequency-selective channels. It is a delay-Doppler (DD) domain modulation that models the information symbols and the channel in the DD domain. This paper considers a pulse-shaped OTFS system with oversampling at the receiver. To mitigate Inter-Frame and Inter-Block Interference, we propose a Reduced Cyclic Prefix (RCP) and Reduced Cyclic Suffix (RCS) frame structure for the OTFS systems that need significantly less overhead than the existing Zero-padded OTFS frame structure. At the receiver, we propose a Finite Impulse Response filter-based Noise Whitening and an iterative delay-time domain Maximal Ratio Combining equalizer that has low complexity and employs oversampling. Through Monte Carlo simulations, we show improved system error performance with oversampling and excess bandwidth. The proposed equalizer provides a significant complexity reduction compared to the existing Message-passing equalizer for a minimal degradation in error performance. We then simulate a Matched Filter Bound (MFB) for OTFS systems. The proposed equalizer is within 3 dB of the MFB performance at an error rate of 10-4.
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issn 2644-125X
language English
publishDate 2025-01-01
publisher IEEE
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spelling doaj-art-a0fbd517712748bcb1fcc61d2bc132b82025-08-20T02:29:27ZengIEEEIEEE Open Journal of the Communications Society2644-125X2025-01-0163357337210.1109/OJCOMS.2025.354035610879026Low-Complexity Oversampled OTFS Receivers With Reduced OverheadNarendra Deconda0https://orcid.org/0009-0000-0635-1993Srikrishna Bhashyam1https://orcid.org/0000-0001-9953-0914Nambi Seshadri2R. David Koilpillai3https://orcid.org/0000-0002-8720-0966Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Electrical Engineering, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Electrical Engineering, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Electrical Engineering, Indian Institute of Technology Madras, Chennai, IndiaOrthogonal Time Frequency Space (OTFS) modulation enables reliable communication in fast time-varying, frequency-selective channels. It is a delay-Doppler (DD) domain modulation that models the information symbols and the channel in the DD domain. This paper considers a pulse-shaped OTFS system with oversampling at the receiver. To mitigate Inter-Frame and Inter-Block Interference, we propose a Reduced Cyclic Prefix (RCP) and Reduced Cyclic Suffix (RCS) frame structure for the OTFS systems that need significantly less overhead than the existing Zero-padded OTFS frame structure. At the receiver, we propose a Finite Impulse Response filter-based Noise Whitening and an iterative delay-time domain Maximal Ratio Combining equalizer that has low complexity and employs oversampling. Through Monte Carlo simulations, we show improved system error performance with oversampling and excess bandwidth. The proposed equalizer provides a significant complexity reduction compared to the existing Message-passing equalizer for a minimal degradation in error performance. We then simulate a Matched Filter Bound (MFB) for OTFS systems. The proposed equalizer is within 3 dB of the MFB performance at an error rate of 10-4.https://ieeexplore.ieee.org/document/10879026/Delay-doppler channelequalizationlow-complexitymatched filter boundmaximal ratio combiningnoise whitening
spellingShingle Narendra Deconda
Srikrishna Bhashyam
Nambi Seshadri
R. David Koilpillai
Low-Complexity Oversampled OTFS Receivers With Reduced Overhead
IEEE Open Journal of the Communications Society
Delay-doppler channel
equalization
low-complexity
matched filter bound
maximal ratio combining
noise whitening
title Low-Complexity Oversampled OTFS Receivers With Reduced Overhead
title_full Low-Complexity Oversampled OTFS Receivers With Reduced Overhead
title_fullStr Low-Complexity Oversampled OTFS Receivers With Reduced Overhead
title_full_unstemmed Low-Complexity Oversampled OTFS Receivers With Reduced Overhead
title_short Low-Complexity Oversampled OTFS Receivers With Reduced Overhead
title_sort low complexity oversampled otfs receivers with reduced overhead
topic Delay-doppler channel
equalization
low-complexity
matched filter bound
maximal ratio combining
noise whitening
url https://ieeexplore.ieee.org/document/10879026/
work_keys_str_mv AT narendradeconda lowcomplexityoversampledotfsreceiverswithreducedoverhead
AT srikrishnabhashyam lowcomplexityoversampledotfsreceiverswithreducedoverhead
AT nambiseshadri lowcomplexityoversampledotfsreceiverswithreducedoverhead
AT rdavidkoilpillai lowcomplexityoversampledotfsreceiverswithreducedoverhead