Stability and throughput optimization of multichannel slotted non-persistent CSMA protocol

Abstract

This paper describes two protocols suitable for a multichannel, multiaccess slotted non-persistent CSMA environment for infinite population, analyses their stability and examines their throughput optimization. The common sensing multichannel slotted non-persistent CSMA (CSCSMA) protocol is an extension of the slotted single channel non-persistent CSMA protocol with an appropriate policy for the selection of the channel in which a station (re)transmits. This policy restricts the control information among the stations, and consequently reduces the cost of the station interface. Pakes's Lemma criteria are applied to define sufficient conditions for ergodicity of the Markov chain, which describes the evolution of the busy station population, and to specify regions in which the multichannel system is stable. Control parameters are the retransmission probabilities. Optimization rules are derived which show that the optimal retransmission probabilities may be expressed as a function of the number of busy stations. The separate sensing multichannel slotted non-persistent CSMA protocol (SSCSMA), using a different policy, distinguishes the channels into two groups: the retransmission channel group devoted in collision resolution; and the transmission channel group for the access of free stations. Stability regions are defined using the results for CSCSMA, and rules for optimal allocation of channels among the two groups are derived for improvement of system performance.