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Adaptive Rate DS-CDMA Systems using Variable Spreading Factors

Adaptive Rate DS-CDMA Systems using Variable Spreading Factors
Adaptive Rate DS-CDMA Systems using Variable Spreading Factors
Abstract—In this contribution, adaptive rate transmissions are investigated in the context of direct-sequence code-division multiple-access (DS-CDMA) systems using variable spreading factors (VSFs). In the context of the recently established family of adaptive rate-transmission schemes, the transmission rate is typically adapted in response to the channel’s fading-induced quality fluctuation. By contrast, in this contribution the transmission rate is adapted in response to the multiuser interference fluctuations encountered. We present the philosophy of the proposed adaptive rate-transmission scheme and analyze the effective throughput as well as the achievable bit error rate (BER) performance, when communicating over additive white Gaussian noise channels. Our study shows that by employing the proposed VSF-assisted adaptive rate-transmission scheme, the effective throughput may be increased by up to 40%, when compared to that of DS-CDMA systems using constant spreading factors. This increased throughput is achieved without wasting power, without imposing extra interference upon other users, and without increasing the BER. Index Terms—Adaptive rate transmissions, code-division multiple access (CDMA), Markov chain, matched filter receiver, multiuser interference, throughput, variable spreading factors (VSFs).
0018-9545
72-81
Yang, L-L.
ae425648-d9a3-4b7d-8abd-b3cfea375bc7
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1
Yang, L-L.
ae425648-d9a3-4b7d-8abd-b3cfea375bc7
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1

Yang, L-L. and Hanzo, L. (2004) Adaptive Rate DS-CDMA Systems using Variable Spreading Factors. IEEE Transactions on Vehicular Technology, 53 (1), 72-81.

Record type: Article

Abstract

Abstract—In this contribution, adaptive rate transmissions are investigated in the context of direct-sequence code-division multiple-access (DS-CDMA) systems using variable spreading factors (VSFs). In the context of the recently established family of adaptive rate-transmission schemes, the transmission rate is typically adapted in response to the channel’s fading-induced quality fluctuation. By contrast, in this contribution the transmission rate is adapted in response to the multiuser interference fluctuations encountered. We present the philosophy of the proposed adaptive rate-transmission scheme and analyze the effective throughput as well as the achievable bit error rate (BER) performance, when communicating over additive white Gaussian noise channels. Our study shows that by employing the proposed VSF-assisted adaptive rate-transmission scheme, the effective throughput may be increased by up to 40%, when compared to that of DS-CDMA systems using constant spreading factors. This increased throughput is achieved without wasting power, without imposing extra interference upon other users, and without increasing the BER. Index Terms—Adaptive rate transmissions, code-division multiple access (CDMA), Markov chain, matched filter receiver, multiuser interference, throughput, variable spreading factors (VSFs).

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Published date: January 2004
Organisations: Southampton Wireless Group

Identifiers

Local EPrints ID: 261264
URI: http://eprints.soton.ac.uk/id/eprint/261264
ISSN: 0018-9545
PURE UUID: 93d0fa81-f8f3-419c-8de3-748d8cf7572b
ORCID for L-L. Yang: ORCID iD orcid.org/0000-0002-2032-9327
ORCID for L. Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

Catalogue record

Date deposited: 27 Sep 2005
Last modified: 18 Mar 2024 02:49

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Contributors

Author: L-L. Yang ORCID iD
Author: L. Hanzo ORCID iD

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