关键词: 无线局域网, 吞吐率公平, 时间公平, 队列调度, NS-3仿真

Abstract:

The DCF (Distributed Coordination Function) used in the IEEE 802.11 protocol provides equal transmission opportunities to each station, which will lead to the performance anomaly in the multi-rate wireless local area network (WLAN). In this paper, we propose a round-robin queue scheduler based on linear scaling of airtime fairness after a detailed theoretical analysis of throughput fairness and airtime fairness. It counts the accurate channel occupancy time of each station, then adopts round-robin to ensure the airtime fairness, and finally improves the system throughput. According to the quality of service (QoS) of data flows, the proposed algorithm can achieve a compromise between transmission efficiency and delay performance by dynamically updating the polling cycle. Simulation by NS-3 and verification by the hardware system show that the proposed algorithm can effectively improve the system uplink and downlink throughput performance while ensuring per-station airtime fairness.

Key words: WLAN, throughput fairness, airtime fairness, queue scheduler, NS-3 simulation