Abstract: The IEEE 802.11e standard defines Hybrid Coordination Function (HCF) which provides QoS support for real-time multimedia applications. Real time multimedia applications having bounded delay constraint, demands frequent scheduling and sufficient amount of Transmission Opportunity (TXOP) to guarantee the delay bound requirement. When a station works with multiple calls, scheduler should choose the proper scheduling interval to meet the delay guarantees. At the same time this scheduling interval has impact over the power conservation of the station. Power conservation is also a much needed property as most of the WLAN stations are nomadic in nature and may be a handheld. This study combines the delay bound and power efficiency requirement and tries to address the solution. This study considers a scenario of stations working with multiple numbers of calls with different delay demands and proposed three different scheduler approaches which vary in scheduling nature. The 3 approaches vary in selecting the Service Interval (SI) to serve the stations. Each approach is analyzed on realizing the guaranteed delay and their effectiveness of power efficiency. The delay performance of delay bound streams under different call combination and varying number of stations for the fixed load is evaluated and analyzed.
J. Jackson Juliet Roy and V. Vaidehi , 2008. Service Interval Impact over Delay and Power Efficiency for Real Time Streams in HCF WLAN. Journal of Mobile Communication, 2: 78-88.