Optimal detection in the presence of co-channel interference and noise in a fast fading environment

The problem of optimally detecting a desired BPSK modulated bit in the presence of another like-modulated interfering signal and additive white Gaussian noise in a fast fading environment is considered. Given certain information about the desired and interfering signals, an optimal detector is proposed which minimizes the bit error rate. It is shown that the optimal detector provides a substantial performance advantage over the matched filter detector when the signal to interference ratio is low. In fast fading, the negative impact of the interfering signal upon the desired signal is reduced to such an extent that the error performance becomes insensitive to the signal-to-interference ratio. This is in sharp contrast to the performance in a non-fading environment.