Performance of a FH/MPSK system with adaptive thresholds over a Rayleigh fading channel

A frequency-hopped/multilevel frequency shift keying (FH/MFSK) system with adaptive thresholds is proposed for a Rayleigh fading channel. The adaptive thresholds are determined by averaging the signal level of output from the envelope detector for each M-ary symbol. A low threshold for a row gives a high detection probability, when the average output of the envelope detector is high. A high threshold for a row gives a low false alarm probability, when the average output of the envelope detector is low. The simulation results show that the FH/MFSK system with adaptive thresholds achieves a lower bit error probability than the system with fixed thresholds