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Crest-Factor Study of MC-CDMA and OFDM

Crest-Factor Study of MC-CDMA and OFDM
Crest-Factor Study of MC-CDMA and OFDM
The crest factor (CF) of M-ary PSK MC-CDMA systems is shown to be dependent upon the aperiodic cross-correlations as well as on the aperiodic autocorrelations of the spreading codes used. Based on this observation, the crest factor distributions of BPSK MC-COMA using two different binary orthogonal spreading sequences namely Walsh codes and orthogonal Gold codes - as well as two polyphase orthogonal sequences - Frank codes and Zadoff-Chu codes - are compared. against that of BPSK OFDM. In a 'lightly loaded' system the polyphase sequences and the orthogonal Gold codes are shown to have better CF distributions. However, in a 'fully loaded' system, Walsh codes exhibit the best crest factor distribution amongst the investigated codes. MC-COMA using Walsh codes was found to exhibit a peak factor reduction of 1.5 over OFDM, when the number of subcarriers Is 16 and a rate 15/16 CF reduction block code Is used, while maintaining the same spectral efficiency. We found that Zadoff-Chu spread MC-COMA showed the best BER performance amongst the considered systems in Rayleigh channels, when Joint-Detection was employed, despite Its heavier clipping than that of the Walsh spread scheme. This is due to its low multiple user interference.
233-237
Choi, B.J.
e5e6cf6f-c5a9-4fa1-a038-81782918a1f9
Kuan, E.L.
67ebe8dd-706a-4c9f-ba00-f38ff3da627f
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1
Choi, B.J.
e5e6cf6f-c5a9-4fa1-a038-81782918a1f9
Kuan, E.L.
67ebe8dd-706a-4c9f-ba00-f38ff3da627f
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1

Choi, B.J., Kuan, E.L. and Hanzo, L. (1999) Crest-Factor Study of MC-CDMA and OFDM. VTC'99 (Fall), Netherlands. 19 - 22 Sep 1999. pp. 233-237 .

Record type: Conference or Workshop Item (Paper)

Abstract

The crest factor (CF) of M-ary PSK MC-CDMA systems is shown to be dependent upon the aperiodic cross-correlations as well as on the aperiodic autocorrelations of the spreading codes used. Based on this observation, the crest factor distributions of BPSK MC-COMA using two different binary orthogonal spreading sequences namely Walsh codes and orthogonal Gold codes - as well as two polyphase orthogonal sequences - Frank codes and Zadoff-Chu codes - are compared. against that of BPSK OFDM. In a 'lightly loaded' system the polyphase sequences and the orthogonal Gold codes are shown to have better CF distributions. However, in a 'fully loaded' system, Walsh codes exhibit the best crest factor distribution amongst the investigated codes. MC-COMA using Walsh codes was found to exhibit a peak factor reduction of 1.5 over OFDM, when the number of subcarriers Is 16 and a rate 15/16 CF reduction block code Is used, while maintaining the same spectral efficiency. We found that Zadoff-Chu spread MC-COMA showed the best BER performance amongst the considered systems in Rayleigh channels, when Joint-Detection was employed, despite Its heavier clipping than that of the Walsh spread scheme. This is due to its low multiple user interference.

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More information

Published date: September 1999
Additional Information: Event Dates: 19-22 September 1999 Address: Amsterdam
Venue - Dates: VTC'99 (Fall), Netherlands, 1999-09-19 - 1999-09-22
Organisations: Southampton Wireless Group

Identifiers

Local EPrints ID: 257172
URI: http://eprints.soton.ac.uk/id/eprint/257172
PURE UUID: e8fb8df2-dbaf-4bad-b9f7-f55ad28f4925
ORCID for L. Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

Catalogue record

Date deposited: 05 Feb 2004
Last modified: 26 Nov 2019 02:06

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Contributors

Author: B.J. Choi
Author: E.L. Kuan
Author: L. Hanzo ORCID iD

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