Performance Analysis of Priority Schemes for IEEE 802.11e Wireless Local Area Networks Using Multiple Flows Distributed Weighted Fair Queuing Algorithm

In this paper, a novel and simple search algorithm called distributed weighted fair queuing (DWFQ) algorithm is proposed for the quality-of-service (QoS) in IEEE 802.11e wireless local area networks (WLANs). We first propose that the IEEE 802.11e enhanced distributed coordination function (EDCF) is an efficient algorithm to support the QoS in WLANs, although it can provide more bandwidth to packets with higher priority. However, when the system under heavy traffic load situation, IEEE 802.11e EDCF can’t guarantee the fair allocation of excess bandwidth of each access categories (ACs), i.e., under heavy traffic load, EDCF guarantees the QoS of packets with higher priority by reducing the QoS of packets with lower priority. This paper discuses an EDCF scheme, in order to distribute bandwidth fairly among different ACs under heavy traffic load situation in WLAN, we propose multiple flows DWFQ algorithm. This algorithm not only supports the concept of differentiating ACs with different priorities but also guarantees the fair allocation of each ACs according to their relative weights. Furthermore, in this propose a mechanism to resolve the overload situation problem and doubling contention window (CW) method to reduce the collision probability. The simulations performed show that multiple flows DWFQ with doubling CW method which can perform an attractive performance even under heavy traffic load.