HCCA Scheduler Design for Guaranteed QoS in IEEE 802.11e Based WLANs

The IEEE 802.11e standard developed by IEEE 802.11TGe intends to provide the 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 standard also defines scheduling and admission control schemes to complement HCCA in meeting these guarantees. However, the reference scheduler has several limitations which render it incapable of providing QoS guarantees to many multimedia applications. In this paper, we propose a new scheduling scheme which overcomes these limitations to provide critical performance guarantees. Simulation experiments show that the proposed scheme successfully enables the HCCA to fulfill the QoS guarantees for wide variety of multimedia applications.