Supporting Video Data in Wireless Sensor Networks

In this paper, we investigate issues associated with the transporting of multimedia streams across wireless sensor networks. We developed a prototype wireless sensor device that is capable of streaming video data through its wireless interface. Our experiments results showed that wireless sensor networks perform poorly with existing networking stack for such applications due to long delivery path and small transmission buffer sizes on the relaying nodes. The effect of a poor link often propagates backwards upstream and causes unnecessary data retransmission. To overcome these problems, we proposed a pipelined transmission scheme with a novel flow control method that monitors local buffer levels. A secondary buffer scheme is also used to reduce the retransmission overhead caused by node failure. Simulation results show that the proposed scheme significantly increase the network efficiency. We also propose a novel stochastic route discovery algorithm for multiple video stream in wireless sensor networks. Our method uses a probing stage where possible routes are explored and their delivery performance recorded. The data collected during the probing stage are used to select the final routes.