Estimation of block error rates for NCFSK modulation on a VHF/UHF mobile radio channel

The authors present an evaluation of the block error rates (BKERs) for noncoherent frequency shift keying (NCFSK) modulation on a Rayleigh fading channel perturbed by additive white Gaussian noise (AWGN). In the past, such calculations have been carried out mostly under the assumption that the channel is very slowly fading, i.e. the received signal strength can be assumed constant over the whole block. This simplifying assumption seldom holds in practice. Two models for estimating these BKERs are presented. The range of parameters considered is: transmission rate of 4096 bps, average signal-to-noise ratios of 5, 10, . . ., 35 dB, Doppler frequencies of 10, 15, . . ., 90 Hz, and blocklengths of 63, 127, . . ., 2047 bits. The formula derived from the first model is very easy to evaluate and gives an average error of about 3%. The formula derived from the second model is slightly harder to evaluate but gives a somewhat lower average error of about 2%. The close agreement between the simulation and predicted results indicates that the models can be used to estimate BKERs quite accurately over the range of parameters considered.>