Sequence Interference Suppression Characteristics of Code-Diversity DS/CDMA over Multipath Fading Channels

Ricardo MANZANILLA  Masanori HAMAMURA  Shin'ichi TACHIKAWA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E84-A    No.12    pp.2983-2990
Publication Date: 2001/12/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Spread Spectrum Techniques and Applications)
Category: 
Keyword: 
DS-CDMA,  code-diversity,  multiple access interference,  near-far problem,  adaptive weight control,  

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Summary: 
In this paper, the sequence interference suppression characteristics of code-diversity DS/CDMA over multipath fading channels are presented. In a code-diversity system, the data signal is modulated with several PN sequences, and using these sequences at the receiver, diversity reception of the signal is carried out to suppress the influence of multiple access interference (MAI) or sequence interference (SI) especially under a near-far problem. First, in a sequence interference and AWGN environment, the basic performance of code-diversity system is presented. Next, in single-path (flat-fading) and multipath fading channels, the average BER performance of the code-diversity system is shown and the observation that the performance of code-diversity system (combined with RAKE reception) is more effective over a multipath fading channel is clarified. Finally, it is presented that by implementing adaptive weight control (AWC) for the code-diversity system over fading channels, the BER performance can further be improved.