The Design and Analysis of Some Computationally Intensive Communication Systems

Abstract

Communication systems may be computationally intensive to study for two main reasons moderate to high bit error rates (BERs) are of interest but the system is highly complex. low BER values are of interest. Hence in this thesis we look at two general systems of current engineering importance. Cellular radio: Here the BER is high but performance is governed by a wide range of parameters so that simulation is too time consuming. Coherent optical systems: Here the system is simple with few parameters but the BER is exceptionally low. Hence the thesis is composed of two parts. In the first part we give a description of cellular radio systems using antenna arrays with optimum linear combining. Using the minimum mean-square error method to evaluate the performance of these antenna arrays, we give the exact distribution and bounds for the bit error rate (BER) performance. This is a timely new result in digital communications theory since prototypes of these systems are already at the experimental stage. In addition the mathematical approach has implications in the area of multivariate statistics. In the second part we investigate the design and analysis of sub-optimal receivers for coherent optical systems using frequency shift keying (FSK) and on-off keying (OOK). We develop sub-optimal receivers using the innovations approach and evaluate them by simulation, and where possible by analytical methods.