Simulation results for an 8-PSK Viterbi receiver

A receiver model for 8-PSK has been simulated. The model has been evaluated for two types of Viterbi decoders, with 8 and 64 states, respectively. The channel considered is a two-ray model with nearly the same ray amplitudes (1 dB difference) and Gaussian white noise added at the input of the receiver. In both cases the symbol error rates for zero multipath delay are comparable to the error rate obtained for conventional differentially demodulated 8-PSK. The advantage is the capability to work in a multipath environment but at the expense of average information rate because of the need of a training sequence. The symbol error performance given is for a receiver without a limiter. The receiver also works with a limiter but then suffers a loss of 1-2 dB for zero multipath delay and up to 5 dB otherwise