A Geometric Distribution for Backoff Time in IEEE 802.11 DCF: An Analytical Study
Youssef Dehbi, Hafssa Benaboud, Noufissa Mikou · 2013
Today's networks, including WLANs, transport different classes of services. A service differenti ation is then essential to provide QoS. However, IEEE 802.11 for WLANs was primarily designed for best effort traffic and did not provide QoS specifications. IEEE 802.11e MAC has been then described to support QoS in WLAN. In this paper, we propose a new scheme for service differentiation which is based on the 802.1 1 standard and requires minor modifications. In fact, we act on DCF which uses the backoff procedure to solve contention in WLANs. For this scheme, we use, instead of the uniform distribution , a geometric distribution for random backoff time selection. Usi ng a multi-class system, we propose three parameterizations of the g eometric distribution which imply different dynamic differen tiation modes and we provide an analytical study, using a Markov chain model, to compare our differentiation modes. We discuss our n umerical results which give the performances evaluation of t he proposed mechanism in term of throughput and delay.