Performance of BPSK and GMSK with multiple cochannel interferers

The bit error rate performance of binary PSK (BPSK) and Gaussian minimum shift keying (GMSK) in the presence of multiple cochannel interferers and additive white Gaussian noise (AWGN) is analysed. In particular, a closed form expression is given to evaluate the bit error probability of BPSK with multiple cochannel interference, whereas GMSK is analyzed by simulation. It is shown that in order to determine the minimum signal-to-interference ratio required to obtain a fixed bit error probability, care must be given to the number of active interferers: in fact, strong differences are found when varying the number of interfering cochannel signals, using the same signal-to-total interference ratio