Author Type

Graduate Student

Date of Award

1997

Document Type

Thesis

Publication Status

Version of Record

Submission Date

October 2026

Thesis/Dissertation Advisor [Chair]

Aalo, Valentine A.

Abstract

This dissertation investigates the performance of different space diversity combining techniques for the wireless mobile communication systems employing Direct Sequence-Code Division Multiple Access (DS-CDMA). It covers two research topics, all falling under the umbrella of diversity combining techniques. The first part deals with diversity reception of wideband DS-CDMA signals in which the diversity branches experience some correlation. This analysis is performed without the usual assumption that diversity branches are independent and hence uncorrelated. In this case, the analysis is limited to the conventional diversity techniques such as maximal ratio combining, equal gain combining and selection diversity. In particular, the effect of correlation on system performance using two correlation profiles namely, the constant and the exponential correlation profiles is explored. In the constant correlation, the correlation between adjacent antenna are equal regardless of the separation between them, while in exponential correlation, it is assumed that the level of correlation between adjacent antennas decreases as their separation increases. The second topic deals with the development of new combining techniques. Two new techniques--the Generalized Selection Diversity Combining (GSDC) and the Maximal Ratio-Selection Diversity Combining (MR-SDC)--are introduced and analyzed in this dissertation. Analytical models which can be used to evaluate the performance of these new techniques are indicated. Results show that GSDC perform significantly better than the conventional selection diversity when two or more larger signals are selected. The MR-SDC technique accounts for the possibility of using a large array of antennas and for occasions when the receiving antennas may not be collocated. Also, it is shown that for the large array of antennas, better performance is achieved when the MR-SDC is employed with the maximum number of subgroups. The figures of merit used in this dissertation are the average Bit Error Rate (BER) and the probability of outage for a given threshold probability of error. Exact and approximate expressions are derived for the average bit error probability as well as for the outage probability while accounting for the effect of multipath fading, multiple access interference and background noise.

Extent

247 p.

Comments

College of Engineering and Computer Science|FAU Electronic Theses and Dissertations Collection|Thesis (Ph.D.)--Florida Atlantic University, 1997.|College of Engineering and Computer Science

Identifier

FADT12524

Format

pdf

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