Collaborative distributed admission control (CDAC) for wireless ad hoc networks

Admission control algorithms have been widely researched for many years to guarantee the Quality of Service (QoS) for multimedia applications over the wired Internet. With the recent surge of wireless home networks, it is increasingly important to employ the admission control mechanisms in order to enhance the performance of the wireless multimedia applications. In this paper, we propose a framework for performing distributed admission control in a collaborative wireless environment. In particular, a wireless device will not inject a new flow into the wireless medium if it determines that by doing so, there is not enough resources to support all the existing flows. Our contributions are threefold. First, we propose a modification to 802.11x based network in order to increase the bandwidth efficiency. Specifically, doubling the contention window (CW) size after a collision is no longer necessary in the proposed wireless network. Second, we provide a performance analysis for the modified 802.11x based wireless networks with multiple flows having different throughput requirements. Third, using the theoretical analysis, we propose two distributed admission control algorithms based on the transmission opportunity (TXOP) and the CW. Simulation results confirm our theoretical predictions on the performance of the proposed admission control algorithms.