Asynchronous, Decentralized DS-CDMA Using Feedback-Controlled Spreading Sequences for Time-Dispersive Channels

Teruhiko MIYATAKE  Kazuki CHIBA  Masanori HAMAMURA  Shin'ichi TACHIKAWA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E91-B    No.1    pp.53-61
Publication Date: 2008/01/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e91-b.1.53
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Cognitive Radio and Spectrum Sharing Technology)
Category: Spectrum Sharing
Keyword: 
spectrum sharing,  spread spectrum,  spreading sequence,  direct sequence,  multipath,  COF,  RAKE,  

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Summary: 
We propose a novel asynchronous direct-sequence code-division multiple access (DS-CDMA) using feedback-controlled spreading sequences (FCSSs) (FCSS/DS-CDMA). At the receiver of FCSS/DS-CDMA, the code-orthogonalizing filter (COF) produces a spreading sequence, and the receiver returns the spreading sequence to the transmitter. Then the transmitter uses the spreading sequence as its updated version. The performance of FCSS/DS-CDMA is evaluated over time-dispersive channels. The results indicate that FCSS/DS-CDMA greatly suppresses both the intersymbol interference (ISI) and multiple access interference (MAI) over time-invariant channels. FCSS/DS-CDMA is applicable to the decentralized multiple access.