CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput

There is a dearth of publications on the subject of spreading-aided Orthogonal Time Frequency Space (OTFS) solutions, especially for Integrated Sensing and Communication (ISAC), even though Code Division Multiple Access (CDMA) assisted multi-user OTFS (CDMA/OTFS) exhibits tangible benefits. Hence, t...

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Main Authors: Hugo Hawkins, Chao Xu, Lie-Liang Yang, Lajos Hanzo
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of Vehicular Technology
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Online Access:https://ieeexplore.ieee.org/document/10849597/
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author Hugo Hawkins
Chao Xu
Lie-Liang Yang
Lajos Hanzo
author_facet Hugo Hawkins
Chao Xu
Lie-Liang Yang
Lajos Hanzo
author_sort Hugo Hawkins
collection DOAJ
description There is a dearth of publications on the subject of spreading-aided Orthogonal Time Frequency Space (OTFS) solutions, especially for Integrated Sensing and Communication (ISAC), even though Code Division Multiple Access (CDMA) assisted multi-user OTFS (CDMA/OTFS) exhibits tangible benefits. Hence, this work characterises both the communication Bit Error Rate (BER) and sensing Root Mean Square Error (RMSE) performance of Code Division Multiple Access OTFS (CDMA/OTFS), and contrasts them to pure OTFS. Three CDMA/OTFS configurations are considered: Delay Code Division Multiple Access OTFS (Dl-CDMA/OTFS), Doppler Code Division Multiple Access OTFS (Dp-CDMA/OTFS), and Delay Doppler Code Division Multiple Access OTFS (DD-CDMA/OTFS), which harness direct sequence spreading along the delay axis, Doppler axis, and DD domains respectively. For each configuration, the performance of Gold, Hadamard, and Zadoff-Chu sequences is investigated. The results demonstrate that Zadoff-Chu Dl-CDMA/OTFS and DD-CDMA/OTFS consistently outperform pure OTFS sensing, whilst maintaining a similar communication performance at the same throughput. The extra modulation complexity of CDMA/OTFS is similar to that of other OTFS multi-user methodologies, but the demodulation complexity of CDMA/OTFS is lower than that of some other OTFS multi-user methodologies. CDMA/OTFS sensing can also consistently outperform OTFS sensing whilst not requiring any additional complexity for target parameter estimation. Therefore, CDMA/OTFS is an appealing candidate for implementing multi-user OTFS ISAC.
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spelling doaj-art-909c5a8060c94d5d9d37cf08370b07cd2025-02-11T00:01:50ZengIEEEIEEE Open Journal of Vehicular Technology2644-13302025-01-01650251910.1109/OJVT.2025.353284810849597CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication ThroughputHugo Hawkins0https://orcid.org/0000-0001-5324-4795Chao Xu1https://orcid.org/0000-0002-8423-0342Lie-Liang Yang2https://orcid.org/0000-0002-2032-9327Lajos Hanzo3https://orcid.org/0000-0002-2636-5214School of Electronics and Computer Science, University of Southampton, Southampton, U.K.School of Electronics and Computer Science, University of Southampton, Southampton, U.K.School of Electronics and Computer Science, University of Southampton, Southampton, U.K.School of Electronics and Computer Science, University of Southampton, Southampton, U.K.There is a dearth of publications on the subject of spreading-aided Orthogonal Time Frequency Space (OTFS) solutions, especially for Integrated Sensing and Communication (ISAC), even though Code Division Multiple Access (CDMA) assisted multi-user OTFS (CDMA/OTFS) exhibits tangible benefits. Hence, this work characterises both the communication Bit Error Rate (BER) and sensing Root Mean Square Error (RMSE) performance of Code Division Multiple Access OTFS (CDMA/OTFS), and contrasts them to pure OTFS. Three CDMA/OTFS configurations are considered: Delay Code Division Multiple Access OTFS (Dl-CDMA/OTFS), Doppler Code Division Multiple Access OTFS (Dp-CDMA/OTFS), and Delay Doppler Code Division Multiple Access OTFS (DD-CDMA/OTFS), which harness direct sequence spreading along the delay axis, Doppler axis, and DD domains respectively. For each configuration, the performance of Gold, Hadamard, and Zadoff-Chu sequences is investigated. The results demonstrate that Zadoff-Chu Dl-CDMA/OTFS and DD-CDMA/OTFS consistently outperform pure OTFS sensing, whilst maintaining a similar communication performance at the same throughput. The extra modulation complexity of CDMA/OTFS is similar to that of other OTFS multi-user methodologies, but the demodulation complexity of CDMA/OTFS is lower than that of some other OTFS multi-user methodologies. CDMA/OTFS sensing can also consistently outperform OTFS sensing whilst not requiring any additional complexity for target parameter estimation. Therefore, CDMA/OTFS is an appealing candidate for implementing multi-user OTFS ISAC.https://ieeexplore.ieee.org/document/10849597/Code Division Multiple Access (CDMA)Integrated Sensing and Communication (ISAC)Orthogonal Time Frequency Space (OTFS)sequence spreading
spellingShingle Hugo Hawkins
Chao Xu
Lie-Liang Yang
Lajos Hanzo
CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput
IEEE Open Journal of Vehicular Technology
Code Division Multiple Access (CDMA)
Integrated Sensing and Communication (ISAC)
Orthogonal Time Frequency Space (OTFS)
sequence spreading
title CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput
title_full CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput
title_fullStr CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput
title_full_unstemmed CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput
title_short CDMA/OTFS Sensing Outperforms Pure OTFS at the Same Communication Throughput
title_sort cdma otfs sensing outperforms pure otfs at the same communication throughput
topic Code Division Multiple Access (CDMA)
Integrated Sensing and Communication (ISAC)
Orthogonal Time Frequency Space (OTFS)
sequence spreading
url https://ieeexplore.ieee.org/document/10849597/
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