Downlink Temporal Fairness in 802.11 WLAN Adopting the Virtual Queue Management

In multi-rate 802.11 wireless LAN, when the wireless node with lower data rate dominates shared channel usage time, the throughput experienced by other nodes transmitting at higher data rates will be drastically reduced. While most fair AQM (active queue management) algorithms are based on throughput fairness, we prove that temporal fair AQM algorithm can achieve more total throughput than throughput fair AQM algorithm in multi-rate 802.11 WLAN. The authors propose a temporal fair AQM-TFRED (temporal fair RED) on AP (access point) in multi-rate 802.11 WLAN. Taking into account the transmission rate of each flow, TFRED sets different drop probability for each flow going through the AP to guarantee equal channel usage time for each wireless node. Analysis and simulation results show that, compared with throughput fair AQM algorithms, TFRED achieves temporal fairness, per-flow throughput protection, and a 40% increase in total throughput.