Performance Investigation of 802.11 MAC DCF

摘要

In the 802.11 protocol, DCF can be termed as an important mechanism in order to access the medium (Channel). This scheme is a random access based scheme which has its fundamentals based upon the efficient usage of CSMA/CA protocol. The retransmission of various collided packets is effectively managed in accordance with the Binary exponential Back-off rules. The waiting time of the BEB is exponentially increased by 2 after every unsuccessful transmission. Every successful transmission sets the back-off stage to initial stage and the contention window is also subsequently set to minimum regardless of any network conditions like the various n number of competing nodes. As the number of competing nodes rises, it can cause substantial performance deprivation as a result of the new collisions caused. This paper highlights and investigates the various modifications possible in the basic calculating methodology of the CW size after every successful transmission and collision of the BEB algorithm and it also evaluates the performance through different simulations possible for it. This paper also throws some significant light on the comparative study conducted on the throughput, end to end delay and packet loss ratio of the investigated schemes along with conventional DCF & one –another.