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CDMA/OTFS sensing outperforms pure OTFS at the same communication throughput

CDMA/OTFS sensing outperforms pure OTFS at the same communication throughput
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, 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.

Code Division Multiple Access, Integrated Sensing and Communication, Orthogonal Time Frequency Space, Sequence Spreading, Integrated Sensing and Communication (ISAC), Orthogonal Time Frequency Space (OTFS), sequence spreading, Code Division Multiple Access (CDMA)
2644-1330
502 - 519
Hawkins, Hugo Zakaria Jose
5f1b37da-dbc7-4edc-9dc4-046b9ecb836b
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Xu, Chao
5710a067-6320-4f5a-8689-7881f6c46252
Yang, Lie-Liang
ae425648-d9a3-4b7d-8abd-b3cfea375bc7
Hawkins, Hugo Zakaria Jose
5f1b37da-dbc7-4edc-9dc4-046b9ecb836b
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Xu, Chao
5710a067-6320-4f5a-8689-7881f6c46252
Yang, Lie-Liang
ae425648-d9a3-4b7d-8abd-b3cfea375bc7

Hawkins, Hugo Zakaria Jose, Hanzo, Lajos, Xu, Chao and Yang, Lie-Liang (2025) CDMA/OTFS sensing outperforms pure OTFS at the same communication throughput. IEEE Open Journal of Vehicular Technology, 6, 502 - 519. (doi:10.1109/OJVT.2025.3532848).

Record type: Article

Abstract

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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CDMA-OTFS_ISAC_v16_OJVT_plus_ack_and_bio - Accepted Manuscript
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Accepted/In Press date: 20 January 2025
e-pub ahead of print date: 22 January 2025
Published date: 22 January 2025
Additional Information: L. Hanzo would like to acknowledge the financial support of the Engineering and Physical Sciences Research Council (EPSRC) projects under grant EP/Y037243/1, EP/W016605/1, EP/X01228X/1, EP/Y026721/1, EP/W032635/1, EP/Y037243/1 and EP/X04047X/1 as well as of the European Research Council’s Advanced Fellow Grant QuantCom (Grant No. 789028). © 20XX IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Keywords: Code Division Multiple Access, Integrated Sensing and Communication, Orthogonal Time Frequency Space, Sequence Spreading, Integrated Sensing and Communication (ISAC), Orthogonal Time Frequency Space (OTFS), sequence spreading, Code Division Multiple Access (CDMA)

Identifiers

Local EPrints ID: 498560
URI: http://eprints.soton.ac.uk/id/eprint/498560
ISSN: 2644-1330
PURE UUID: 932e3849-f144-4823-a2c5-f4bd1a22f103
ORCID for Hugo Zakaria Jose Hawkins: ORCID iD orcid.org/0000-0001-5324-4795
ORCID for Lajos Hanzo: ORCID iD orcid.org/0000-0002-2636-5214
ORCID for Chao Xu: ORCID iD orcid.org/0000-0002-8423-0342
ORCID for Lie-Liang Yang: ORCID iD orcid.org/0000-0002-2032-9327

Catalogue record

Date deposited: 20 Feb 2025 18:22
Last modified: 15 May 2025 02:05

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Contributors

Author: Hugo Zakaria Jose Hawkins ORCID iD
Author: Lajos Hanzo ORCID iD
Author: Chao Xu ORCID iD
Author: Lie-Liang Yang ORCID iD

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