Broadcasting In Multi-channel And Multi-hop Wireless Networks

Recent years have seen significant interest in using the multi-hop wireless networking paradigm for building ad hoc networks, sensor networks and mesh networks. A fundamental obstacle to building large scale multi-hop networks is the insufficient network capacity when route lengths and network density increase due to the limited spectrum shared in the neighborhood. The use of multiple radios which tuned to orthogonal channels can significantly improve the network capacity by employing concurrent transmissions under different channels, and that motivates the development of new protocols for multi-radio multi-channel networks.Broadcast is an important operation in multi-hop wireless networks. It is not only an important communication pattern in many wireless applications, but also the basic means for route discovery in unicast routing and a useful tool to maintain the multicast membership and multicast tree in some multicast routing protocols. Many approaches have been proposed for broadcasting problems. But they are not efficient in multi-radio multi-channel networks, since they do not consider its unique characteristics. In this paper, we study the efficient broadcasting problem under the multi-radio multi-channel and multi-hop environment. We propose 3 algorithms which focus on reducing the redundant traffic of broadcasting, mitigating the collision phenomenon, and improving the broadcasting capacity respectively. By reducing the broadcasting problem into the minimal strong connected dominating set problem of interface-extended graph, we propose a Self-Pruning approach to reduce the redundancy. Using Neighbor-Designation approach, we mitigate the collisions problem by comparing the broadcast routes history. We also proposed a conflict-free broadcast schedule scheme, which aims at improving the throughput of the networks, by using depth-first search technology to construct the broadcast tree.To evaluate these algorithms, we extend current NS-2 network simulator by adding multi-interface support for the mobile node. We implement our algorithms and evaluate them under different conditions. Simulation results show the efficiencies of our approaches.