M-ary CPFSK-DPD with L-diversity maximum ratio combining in Rician fast-fading channels

We derive a formula for the bit error probability (BEP) of M-ary continuous phase frequency shift keying with differential phase detection and maximum ratio combining diversity in Rician fast-fading channels. We assume that transmitter and receiver filters distort the signal and limit the noise. We compute the BEP as a function of energy-to-noise ratio per bit (E/sub b//N/sub 0/) and other system and channel parameters: Rician factor K=0, 6 dB, 10, /spl infin/; number of diversity channels L=1, 2, 3; Doppler frequency shift f/sub D/T=0, 0.01, 0.02; Butterworth filters in transmitter and receiver of order N/sub T/=3 and N/sub R/=4; optimal sampling time and filter bandwidth. In all cases the BEP is significantly reduced by diversity.