DS-CDMA Non-linear Interference Canceller with Multiple-Beam Reception

Kazuto YANO  Susumu YOSHIDA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E89-A   No.10   pp.2609-2621
Publication Date: 2006/10/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e89-a.10.2609
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Information Theory and Its Applications)
Category: Spread Spectrum
multirate DS-CDMA,  multistage MAI canceller,  multiple-beam reception,  complexity reduction,  interference suppression,  

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In this paper, a multistage parallel interference canceller (MPIC) with multiple-beam reception for a DS-CDMA system is proposed to suppress multiple access interference (MAI) effectively. Its aim is to reduce the computational complexity of the conventional MPIC cascaded with an adaptive array antenna. It employs multiple fixed beams based on phased array and selects suitable beams to demodulate the transmitted signal of each user. Then it suppresses residual interference signals by the MPIC cascaded with multiple-beam receiver. Its bit error rate (BER) performance is evaluated by computer simulations assuming an uplink single-chip-rate multiple-spreading-factor DS-CDMA system over both exponentially decaying 5-path and equal average power 2-path Rayleigh distributed channels. When there are 16 users in an 120-sectored single cell, the proposed receiver with 6-element array antenna and 2-stage MPIC shows better or comparable BER performance compared with that of the conventional receiver. Moreover, the proposed receiver with 8 beams can reduce the number of complex multiplications to about 40% of that of the complexity-reduced conventional receiver over 5-path channels.