Optimal detection of a BPSK signal with unsynchronized co-channel interferers

The problem of optimally detecting a desired BPSK modulated bit in the presence of another bit unsynchronized BPSK modulated interfering signal and additive white Gaussian noise is considered. Given certain information about the desired and interferer signals, the minimum achievable bit error rates for two types of receiver models are obtained and compared with that for a conventional matched filter. It is found that knowledge of the interferer signal´s carrier phase is important when the signal-to-interference ratio is low. The effect on bit error rate of a frequency offset between the desired and interferer signals is also studied. Finally, performance sensitivity to errors in estimating the interferer signal´s carrier phase and the bit timing difference between the desired and interferer signals is examined