Asymptotic Weighted Fair Queuing (AWFQ) for IEEE 802.11 Point Coordination Function (PCF)

In this paper, we present a scheduling algorithm for the centralized controller in the IEEE 802.11 standards. The proposed algorithm is specifically designed for the Point Coordination Function (PCF). Although many scheduling algorithms have been proposed, none of them could be directly applied to the PCF uplink scheduling. Most of the literature work focuses on downlink traffic, in which Access Point (AP) could easily gather necessary information, such as queue length, packet arrival rate, and packet delay, for packet scheduling. The scheduling for uplink traffic is more challenging because the information for scheduling is distributed in each wireless station. We propose Asymptotic Weighted Fair Queuing (AWFQ) to approximate Weighted Fair Queuing (WFQ) for uplink scheduling. In AWFQ, bandwidth is allocated dynamically according to channel condition. In addition, each wireless station will give up its transmission opportunity when confronting a poor channel condition. With the proposed scheme, the channel utilization is improved. The average packet delay is reduced as well. An attractive feature of the proposed algorithm is that it could be implemented with only minor modifications to the IEEE 802.11 standards.