Queueing Analysis of 802.11e HCCA with Variable Bit Rate Traffic

The IEEE 802.11e draft standard currently being developed by IEEE 802.11TGe proposes to enable the much needed Quality of Service (QoS) support for the popular 802.11 based wireless local area networks (WLAN) through the introduction of Hybrid Coordination Function (HCF). The HCF Controlled Channel Access (HCCA) designed as a part of HCF is the medium access mechanism for parameterized QoS and is suitable for multimedia applications requiring hard QoS guarantees. The draft standard also defines scheduling and admission control schemes to complement HCCA in meeting these guarantees. However, most of the popular multimedia applications generate Variable Bit Rate (VBR) traffic that brings challenge to the HCCA and its scheduler and admission controller design. This paper introduces a novel queueing analytic framework that will be useful to analyze the performance of HCCA in provisioning required QoS for VBR traffic applications. The analysis also provides important insights that could be useful to improve the HCCA scheduler and admission controller designs.