Variable rate adaptive channel coding for coherent and non-coherent Rayleigh fading channel

We have evaluated the information theoretical performance of variable rate adaptive channel coding for the Rayleigh fading channel. The channel states are detected at the receiver and fed back to the transmitter by means of a noiseless feedback link. Based on the channel state information, the transmitter can adjust the channel coding scheme accordingly. The channel capacity and the error exponent of are evaluated and the optimal control rules are found for coherent and non-coherent Rayleigh fading channel with feedback of channel states. It is shown that the variable rate scheme can only increase the channel error exponent. The effects of peak time constraint and the finite feedback delays are also considered. Finally, we compare the performance of the variable rate adaptive channel coding in high bandwidth-expansion systems (CDMA) and high bandwidth-efficiency systems (TDMA).