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

Teruhiko MIYATAKE; Kazuki CHIBA; Masanori HAMAMURA; Shin'ichi TACHIKAWA

doi:10.1093/ietcom/e91-b.1.53

Special Section on Cognitive Radio and Spectrum Sharing Technology

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

Teruhiko MIYATAKE, Kazuki CHIBA, Masanori HAMAMURA, Shin'ichi TACHIKAWA

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Keywords: spectrum sharing, spread spectrum, spreading sequence, direct sequence, multipath, COF, RAKE

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2008 Volume E91.B Issue 1 Pages 53-61

DOI https://doi.org/10.1093/ietcom/e91-b.1.53

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Abstract

We propose a novel asynchronous direct-sequence codedivision 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.

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