Optimum diversity receiver for cochannel interference with non-zero symbol timing offset in digital mobile radio

Abstract

This paper presents the analysis and performance of the optimum diversity receiver in mobile radio environments with QAM data transmission, two-ray frequency-selective Rayleigh-fading channel, Gaussian noise and co-channel interference (CCI), while the symbol timing offset between the desired and co-channel interference is considered. With this non-zero random offset value, the co-channel interference is shown as a wide-sense stationary process (WSS). An optimum diversity receiver is proposed for the new WSS co-channel interference model. Linear and decision-feedback equalization techniques are used in the design of the optimum diversity receivers. By simulation techniques, we show that the degradation due to the WSS co-channel interference is smaller than that caused by the equivalent additive Gaussian noise or cyclostationary cochannel interference, especially in highly co-channel interference dominated channels and also in the system where a decision-feedback equalizer is employed.