Smart antenna in DS-CDMA mobile communication system using circular array technique
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Authors
Ng, Stewart Siew Loon
Subjects
Smart Antenna
Uniform Circular Array
Hata Model
Rayleigh Fading
DS-CDMA
Tapped-Delay Line
Uniform Circular Array
Hata Model
Rayleigh Fading
DS-CDMA
Tapped-Delay Line
Advisors
Ha, Tri T.
Lebaric, Jovan
Date of Issue
2003-03
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
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.
Type
Thesis
Description
Series/Report No
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
xx, 79 p. : ill. (some col.) ;
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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