Performance of a wireless media access protocol on a Markovian fading channel

Abstract

The throughput performance of a wireless media access protocol taking into account the effect of channel fading is analyzed. For efficient access on the uplink (mobile-to-base), the protocol makes use of the uplink channel status information which is conveyed to the mobile through a busy/idle flag on the downlink (base-to-mobile link). A first-order Markov model is used to describe the packet successes and failures on a Rayleigh fading channel. A closed-form expression for the throughput is derived by modeling the system as a finite-state, discrete-time Markov chain. The analytical results obtained through the first-order Markov approximation of the channel are compared to those obtained from an i.i.d channel model. The Markovian fading channel model is shown to provide better performance results than the i.i.d channel model. Results obtained by direct simulation of the fading process and the protocol operation show that a first-order Markov approximation of the fading process is quite accurate.