Providing quality of service guarantees in wireless LANs compliant with 802.11e

摘要

Quality of Service (QoS) support is a key attribute of a broadband communication system and is missing in 802.11-based wireless LANs. Recognizing the need, Task Group e (TGe) is working towards 802.11e, an evolution of the standard that provides the means for denning desirable QoS requirements for the traffic streams as well as a framework for scheduling schemes to achieve them. In this paper we propose a scheduling scheme for QoS guarantee provisioning that exploits and is fully compliant with the specifications of 802.11e. The scheduler operates at the access point and relies on the measurement and control parameters available in the fields of the 802.11e header to determine access during the evolution of PCF called HCF. Our scheme takes channel conditions under consideration in making these decisions, since information about the channel state can be conveyed now with the recent modifications adopted by TGh. Evaluation of our algorithm through simulation study shows significant performance improvement compared to earlier schemes that could not take channel conditions into consideration in making scheduling decisions.