A Finite State Model for IEEE 802.11 Wireless LAN MAC DCF

The international standard IEEE 802.11 wireless LAN protocol is a popular standard for wireless local area networks. Its medium access control layer (MAC) is a carrier sense multiple access with collision avoidance (CSMA/CA) design, although collisions cannot always be prevented, randomized exponential backoff rule is used in the retransmission scheme to minimize the likelihood of repeated collisions. To work around this problem, we identify state transition of the protocol that can be used to simplify the models and make verification feasible. This paper explains the state transition model of two way handshake mechanism of IEEE 802.11 standard for MAC DCF. Using these observations, a time variant generalized state transition model for channel, sender and destination station has been described. The proposed model has been validated using network simulator ns-2.