In this paper, we study the correlation properties of the fading mobil
e radio channel, Based on these studies, we model the channel as a one
-step Markov process whose transition probabilities are a function of
the channel characteristics. Then we present the throughput performanc
e of the Go-Back-N and selective-repeat automatic repeat request (ARQ)
protocols with timer control, using the Markov model for both forward
and feedback channels, This approximation is found to be very good, a
s confirmed by simulation results.