On the unfair channel access phenomenon in wireless LANs

This paper shows that the relative collision probability for packets in wireless LAN 802.11 networks decreases with increasing load offered by the respective station. This denotes a clearly unfair channel access which is important to be aware of, e.g., when collision probabilities are measured and used for reactive control of contention windows. We model the unfair channel access phenomenon analytically and semi-analytically for bidirectional constant bit rate and unidirectional TCP traffic and compare the results with those from simulations.