Construction of Dual OVSF Codes with Lower Correlations

Jia HOU  Moon Ho LEE  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E89-A   No.11   pp.3363-3367
Publication Date: 2006/11/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e89-a.11.3363
Print ISSN: 0916-8508
Type of Manuscript: LETTER
Category: Coding Theory
WCDMA,  OVSF,  BER,  AWGN,  multi-user environment,  

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In wide-band code division multiple access (WCDMA), orthogonal variable spreading factors (OVSF) codes are assigned to different users to preserve the orthogonality between users' physical channels. In this letter, we present the dual OVSF code, which can transmit the variable data rates by suing two different modulated signals without loss of the orthogonality. The bit error rate (BER) performance under a multi-user environment suffering the additive white Gaussian noise (AWGN) channel and correlations of those codes are evaluated. The results demonstrate that the proposed dual OVSF scheme could provide flexible rates and lower correlation values with a slight increase in complexity.