A new call admission control method for providing desired throughput and delay performance in IEEE802.11e wireless LANs

摘要

The draft IEEE 802.11e standard aims at providing quality of service (QoS) support in 802.11 wireless local area networks (WLANs). Enhanced distributed coordination function (EDCF), being the fundamental medium access control mechanism in IEEE 802.11e, can only provide service differentiation but offers no QoS guarantees. While service differentiation does not perform well under high traffic load conditions, call admission control (CAC) becomes necessary in order to provide and support the QoS of existing calls. In this paper, we first analyze the saturation throughput and mean access delay performance of differentiated service provided by EDCF. Specifically, we investigate the impact of transmission opportunity (TXOP) and wireless channel errors on the performance of the EDCF. Based on the results from this analysis, we propose a new CAC algorithm that provides the desired throughput and access delay performance. Simulated performance results demonstrate the effectiveness of the proposed CAC algorithm