Antenna array configuration effects on the radiation pattern and BER of the modified adaptive CMA in CDMA based systems

Abstract

A time-varying multipath channel model for wireless systems as an extended form of Gaussian Wide Sense Stationary Uncorrelated Scattering (GWSSUS) model and a modified adaptive Constant Modulus Algorithm (CMA) for use in a CDMA system environment are presented. The large angular spread of the signal sources is considered. The post-correlation model (PCM) of data structure is used in CMA, too. The modified adaptive CMA algorithm has faster convergence and causes better radiation patterns in different array geometries to track signal sources. Comparing the signal to noise ratio at the output of the algorithm for uniform linear and circular arrays with theoretical results proves the efficiency of the presented algorithm. BER performance of the algorithm for different element numbers of uniform linear and circular array antennas with DBPSK modulation is also studied.