Call Admission Control Scheme for the IEEE 802.16e at Vehicular Speeds

The IEEE 802.16e standard has emerged as an exciting mobile wireless broadband technology that promises to deliver both high throughput and guaranteed quality of service (QoS). Call admission control (CAC) scheme serves as a great utility for WiMAX, which ensures that resources are not over committed and thereby, all existing connections enjoy guaranteed quality of service. Existing CAC schemes largely depend on computation of available resources while making an acceptance or rejection decision once a new request arrives. Since wireless channels are not as reliable as wired communication, CAC scheme in WiMAX communication faces a serious challenge of making a right estimate of the usable channel capacity while computing the available resources at various communication scenarios. Existing CAC schemes do not consider the impact of mobility at vehicular speeds when computing the usable link capacity and available resources. In this paper, we propose a new CAC scheme that estimates the usable link capacity for WiMAX communication at various vehicular speeds and uses this information while making a CAC decision. Extensive simulation results show that the proposed scheme achieves lower dropping rate and improved QoS compared to existing schemes.