Deriving the Suspended Backoff Counter Value Distribution in CSMA/CA

of today's wireless LANs and PANs employ the use of the CSMA/CA protocol. In CSMA/CA, a randomly initialised counter is used to reduce the probability of nodes accessing the channel at the same time. In most implementations, this counter is suspended when the channel is idle. In this paper, we derive and verify through simulation the exact analytical expression for the distribution of this counter's value. For further validation, we show how it can be used to obtain the protocol's idle period distribution under saturation loads. For this latter distribution, we provide simulation results to show the accuracy of the formula compared to one derived using the de+facto first+order Markov channel state model.