Experimental Evaluation of Performance Anomaly in Mixed Data Rate IEEE802.11ac Wireless Networks

IEEE 802.11 wireless local area networks (WLANs) are shared networks, which use contention-based distributed coordination function (DCF) to share access to wireless medium. The performance of DCF mechanism depends on the network load, number of wireless nodes and their data rates. The throughput unfairness also known as performance anomaly is inherent in the very nature of mixed-data rate Wi-Fi networks. This unfairness exhibits itself through the fact that slow clients consume more airtime to transfer a given amount of data, leaving less airtime for fast clients. In this paper, we evaluate the performance anomaly of mixed rate wireless networks and present the results of practical experiments benchmarking throughput of a mixed rate 802.11ac wireless network. These results clearly show that even the most recent wireless standard still suffers from the airtime consumption unfairness. At the end of the paper we analyse related works offering possible solutions and discuss our approach to evade performance degradation in mixed data rate Wi-Fi environments.