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Improving the Throughput of DS-CDMA Systems Using Adaptive Rate Transmissions Based on Variable Spreading Factors

Yang, L.L. and Hanzo, L. (2002) Improving the Throughput of DS-CDMA Systems Using Adaptive Rate Transmissions Based on Variable Spreading Factors At VTC'2002, (Fall), Canada. 24 - 28 Sep 2002. , pp. 1816-1820.

Record type: Conference or Workshop Item (Other)


In this contribution adaptive rate transmissions are investigated in the context of DS-CDMA systems using variable spreading factors (VSF). In contrast to conventional adaptive rate transmission schemes, where the transmission rate is usually adapted in response to the channel fading, in this contribution the transmission rate is adapted in response to the multiuser interference (MUI) level. We present the philosophy of the proposed adaptive rate transmission scheme and analyze the effective throughput as well as the resultant bit error rate (BER) performance, when communicating over additive white Gaussian noise (AWGN) channels. Our study shows that when the number of active users in a DS-CDMA system can be modelled with the aid of a Markov chain and when the conventional matched filter based receiver is employed, the VSF-assisted adaptive rate transmission scheme is capable of substantially increasing the system’s effective throughput. Specifically, our results show that 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.

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Published date: 2002
Additional Information: Event Dates: 24-28 September 2002
Venue - Dates: VTC'2002, (Fall), Canada, 2002-09-24 - 2002-09-28
Organisations: Southampton Wireless Group


Local EPrints ID: 257149
PURE UUID: 7bb82c87-9a8e-4189-8814-0f7e002ef125
ORCID for L.L. Yang: ORCID iD

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Date deposited: 26 Jun 2003
Last modified: 18 Jul 2017 09:41

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

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