Optimizing Patching-based multicast for video-on-demand in wireless mesh networks

In this work, we study the application of video-on-demand (VoD) in wireless mesh networks (WMN), a next generation edge technology to provide broadband data access in residential, business and even city-wise networks. We adopt a Patching-based multicast technique to better utilize the bandwidth resources in the mesh network. We optimize the Patching-based multicast by addressing two critical problems, namely, the Minimum Cost Multicast Tree (MCMT) problem and the Maximum Benefit Multicast Croup (MBMG) problem. The MCMT problem is to find a MCMT in the network. We show that finding such a tree in the WMN can be formulated as a graph theory problem, which is to find the tree with minimum number of non-leaf nodes, and which spans all the nodes in the multicast group. We further prove the problem is NP-hard and propose a fast greedy algorithm to accommodate the real-time feature of the VoD application. We solve the MBMG problem by minimizing the communication of a Patching group in the entire network. A Markov model is proposed to capture the growth of the multicast group in the WMN. Simulation study results validate the proposed solutions of the two problems. Copyright (C) 2009 John Wiley & Sons, Ltd