A new scheduling algorithm for improving up/down time TCP fairness

Based on the analysis of the problem in wireless local area networks (WLAN) that lead to the significant unfairness between TCP flows because of the greedy closed loop control nature of the transmission control protocol (TCP), the equal channel access probabilities guaranteed by the media access control (MAC) layer, and the performance anomaly of the wireless channel, this paper proposes a new scheduling algorithm for up/down TCP flows in WLANs known as the Up/ Down Time Fair LAS (UDTFLAS). Taking into account the transmission rate of each flow, UDTFLAS sets higher transmission probability for higher wireless data rate flows to guarantee equal channel usage time for each up/down TCP flow. The analysis and simulation results show that, compared with the throughput of fair scheduling algorithms, UDTFLAS can achieve per-flow throughput protection and up/down time fairness, and can increase the total throughput.