The impact of backoff, EIFS, and beacons on the performance of IEEE 802.11 wireless LANs

In late 1997, IEEE standardized the physical layers and the medium access for wireless local area networks. This paper presents a performance study of the distributed coordination function, the fundamental contention based access mechanism. Most performance studies adopt unchecked simplifying assumptions or do not reveal all details of the simulation model. We develop a stochastic Petri net model, which captures all relevant system aspects in a concise way. Simulation allows to quantify the influence of many mandatory features of the standard on performance, especially the backoff procedure, extended interframe spaces, and the timing synchronisation function. This study also serves to identify conditions when simplifying assumptions commonly used in analytical modeling are justified.