Smart Antenna in DS-CDMA Mobile Communication System Using Circular Array Technique
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. The authors 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 was demonstrated that the optimization process is computationally expensive and, therefore, minimum taps should be used. The results illustrate that, 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 narrowband adaptive array system. (1 table, 49 figures, 12 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2003
- Accession Number
- ADA415141
Entities
People
- Stewart S. L. Ng
Organizations
- Naval Postgraduate School