Semianalytic computer simulation of digital communication systems

Abstract

Digital communication systems are subject to various realization imperfections and outer disturbances. The effect of such problems on the systems performance are difficult to solve using only analytical techniques. So, computer simulation becomes an invaluable aid. In this thesis for digital communication system simulations a software package SSNDC-Semianalytic Simulator of Nonlinear Digital Channels- has been developed. This software is capable of simulating coherent phase shift keying systems with linear or nonlinear channels in an additive white Gaussian noise environment. All the signals and filters are complex lowpass equivalents of their bandpass counterparts. First a noisefree simulation with a short information sequence is performed and then the effect of additive noise is analytically added. This method together with complex lowpass representation of signals results in much faster simulations than thestandard Monte Carlo method. The program has a modular structure presenting convenience for future modifications. The input data preparation is arranged in the form of menu-driven interactions. The mathematical theory for the development of the modules of the software is included. Finally. the results of the simulation as well as their comparison with theoretical solutions or their counterparts in literature are presented.