Capacity analysis for a CDMA system

Abstract

Most research on capacity analysis of code division multiple access (CDMA) cellular systems is based on the assumption that all cells have a fixed number of mobile users. Since real traffic load changes from cell to cell, such a capacity is only a special case in mobile cellular networks. The capacity of a CDMA system is mainly determined by the total interference introduced by the mobiles in the same frequency bandwidth. In this thesis, we first analyse this cochannel interference. Statistical characteristics of the interference are given by theoretical analysis and computer simulation. A method based on the system state, interference coefficients, propagation model and link quality is proposed to calculate reverse link capacity of a CDMA system with non-uniform traffic load. The effects of various factors, such as link quality requirement, propagation parameters (shadow fading deviation [sigma], path loss exponent _), voice activity, and other cell traffic load on capacity, are investigated based on two different simulation models. The numerical results for different propagation parameters and link quality requirements are presented and discussed. (Abstract shortened by UMI.)