Performance analysis of asynchronous FFH-SSMA communication systems with frequency errors in Rayleigh fading channels

We derive expressions for the bit error rate (BER) for an asynchronous FFH-SSMA system using a Markov hopping pattern and consider the occurrence of all possible hits by multiple interfering users for outdoor radio communications. The modulation scheme considered is the noncoherent M-ary frequency shift-keying (MFSK) with a threshold level, which is selected properly depending on channel and system conditions. The outdoor environment is described as the Rayleigh fading channel with an RMS delay spread of 10 to 25 /spl mu/s. The normalized frequency error of 0.4 requires about 6 dB additional SNR compared with the perfect frequency synchronized case at BER=10/sup -3/.