Physical rate based admission control for HCCA in IEEE 802.11e WLANs

The IEEE 802.11 working group is currently working on the support of quality of service (QoS) in a new standard called IEEE 802.lie which introduces the so-called hybrid coordination function (HCF). A simple admission control unit has already been developed as a reference for HCF controlled channel access (HCCA) in a recent TGe draft. However, this reference scheme is inefficient because it is implemented based on the minimum physical rate from which the mobile stations´ actual physical rates deviate greatly at most of the time. In this paper, we propose a physical rate based admission control scheme (PRBAC) which enhances the reference scheme by taking account of both the wireless channel characteristics and the stations´ mobility. Numerical analysis and simulation results show the significant improvement of the proposed admission control scheme.