Analytical Modeling of the Link Delay Characteristics for IEEE 802.11 DCF Multi-Rate WLANs

Performance evaluation of IEEE 802.11 DCF has been widely studied under the assumption of a single transmission rate by all competing nodes. In practice, however, stations typically use different transmission rates. This is done to match to the changing channel conditions. Stations with poor channel conditions typically employ lower transmit rates in comparison to stations with better channel conditions. Under such scenarios, the throughput of each station becomes independent of its own transmit rate; rather it gets bounded by the slowest transmitting peer. This has been popularly classified as the performance anomaly problem. This paper provides a simple yet accurate analytical framework to study the link delay characteristics of such multi-rate networks