Rate-adaptive broadcast routing and scheduling for video streaming in wireless mesh networks

In this paper, we address the problem of broadcast routing and scheduling of video streaming for delay-sensitive applications in backbone WMNs. Given a source node and a set of destinations, our task is to build a broadcast routing tree and compute an optimal transmission schedule such that the network throughput for the source to broadcast streaming data to all the destinations is maximized. The problem is challenged by both rate-adaptive broadcast and inter/intra-flow interference caused by video streaming. We divide the whole period for video broadcast into identical time frames and prove that maximizing the total throughput can be converted into minimizing the length of a time frame. We formulate the minimization problem as a mixed integer quadratically constrained program and propose a three-step method as a solution. Firstly, we build the broadcast routing tree by defining a new routing metric to select the relay nodes. Then we use local search to adjust the tree structure. Last, we propose a greedy method to make scheduling of concurrent transmissions without causing inter/intra-flow interference. Extensive simulations have demonstrated that our proposed method can improve the performance significantly compared with existing routing and scheduling methods.