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Smart antenna in DS-CDMA mobile communication system using circular array technique

Approved for public release, distribution is unlimited / This thesis examines a circular adaptive antenna array used at the mobile station for a typical Direct Sequence Code Division Multiple Access (DS-CDMA) cellular mobile communications system. The primary objective is to reduce co-channel interference of a wideband CDMA cellular network under a multi-path fading environment. We analyzed the performance of a randomly positioned mobile terminal with a randomly orientated adaptive antenna array in the forward channel (base-station to mobile) of a multi-cell DS-CDMA system and established four performance boundaries. A single complex circular adaptive weight in each element channel of a circular adaptive array sufficiently processes narrowband signals. However, in order to process broadband signals, a tapped-delay line (transveral filter) is required. This tapped-delay line is employed because it can adjust the frequency dependent amplitude and phase. The performance of a DS-CDMA cellular system with a mobile terminal equipped with a circular array and a tapped-delay line is analyzed. It has been demonstrated that the optimization process has been extremely computationally expensive and hence minimum taps should be used for practical considerations. The results illustrated that, in general, for a four-element circular array system, a two tapped-delay line would be sufficient to equalize the broadband signal while providing a similar performance level to that of a narrow-band adaptive array system. / http://hdl.handle.net/10945/1080 / Major, Republic of Singapore Air Force

Identiferoai:union.ndltd.org:nps.edu/oai:calhoun.nps.edu:10945/1080
Date03 1900
CreatorsNg, Stewart Siew Loon
ContributorsHa, Tri T., Lebaric, Jovan, Electrical Engineering
PublisherMonterey, California. Naval Postgraduate School
Source SetsNaval Postgraduate School
Detected LanguageEnglish
TypeThesis
Formatxx, 79 p. : ill. (some col.) ;, application/pdf
RightsCopyright is reserved by the copyright owner.

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