Available Bandwidth in Multirate and Multihop Wireless Sensor Networks

In this paper, we derive a theoretical model to calculate the available bandwidth of a path and study its upper and lower bounds with background traffic. We show that the clique constraint widely used to construct upper bounds does not hold any more when links are allowed to use different rates at different time. In our proposed model, traditional clique is coupled with rate vector to more properly characterize the conflicting relationships among links in wireless sensor networks where time-varying link adaption is used. Based on the model, we also investigate the problem of joint optimization of QoS routing and propose several routing metrics. The newly proposed conservative clique constraint performs the best among the studied metrics in estimating available bandwidth of flows with background traffic.