Degree Type

Dissertation

Date of Award

2002

Degree Name

Doctor of Philosophy

Department

Electrical and Computer Engineering

First Advisor

Jennifer Davidson

Abstract

Wideband Code Division Multiple Access (WCDMA) communications in the presence of channel uncertainty poses a challenging problem with many practical applications in the wireless communications filed. In this dissertation, robust linear-quadratic (LQ) receivers for time-varying, frequency-selective CDMA channels in the presence of uncertainty regarding instantaneous channel state information are proposed and studied. In order to enhance the performance of the LQ receivers, a novel modulation technique adaptive multicoding is employed. We proposed a simple, intuitively appealing cost function the modified deflection ratio that can be maximized to find signal constellations and associated LQ receivers that are optimal in a certain sense. We discuss the properties of the proposed LQ cost function and derive a related adaptive algorithm for the simultaneous design of signals and receivers based on a simple multicoding technique. The Chernoff bound for the LQ receivers is also derived to compensate for the analytical intractability of the probability of bit error. Finally, in order to achieve higher data rate transmission in favorable channels, we extend our approach from binary signals to M-ary signal constellations in a multi-dimension subspace.

DOI

https://doi.org/10.31274/rtd-180813-114

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu

Copyright Owner

Jianjun Ni

Language

en

Proquest ID

AAI3073471

File Format

application/pdf

File Size

102 pages

Share

COinS