OPTIMUM LINEAR DIVERSITY RECEIVERS FOR MOBILE COMMUNICATIONS

This paper analyzes and quantifies the performance of a space diversit y combining receiver operating in a mobile radio environment with quat ernary phase-shift-keying transmission, frequency-selective Rayleigh m ultipath fading, and cochannel interference (CCI). The receiver has an infinite-length filter in each branch of the diversity combiner, and the filters are optimized jointly according to the minimum mean-square -error criterion. The link bit error rate is estimated accurately usin g Metzger's algorithm, which approximates the probability density func tion of the combined intersymbol interference (ISI) and CCI. We presen t numerical performance results showing the influence of the diversity order, the number of dominant cochannel interferers, the multipath ch annel's delay spectrum, and the root-mean-square delay spread. The res ults show that, under certain conditions, the optimum linear receiver can almost completely eliminate all ISI and CCI while providing near-o ptimum noise filtering.