不同于无线传感器网络和移动AdHoc网络,无线Mesh网络中的组播主要侧重于提高吞吐量,而干扰是影响吞吐量的重要因素.在构建组播拓扑时,传统的方法主要考虑最小价值或最短路径,而通过减少干扰来提高组播性能的研究较少,且它们的干扰计算方法都采用单播的思想,并不适合于组播.例如,当n个接收节点同时从一个节点接收数据时,在组播中这”个接收节点之间不存在干扰,而在单播中认为存在干扰.因此,提出了组播冲突图来计算组播干扰,给出组播树干扰的定义.可以发现,求最小干扰组播扰树是NP完全问题,然后提出基于万有引力的启发式算法构建具有较小干扰的组播树.为了适用于多信道的情况,提出了满足不同干扰范围的多跳信道分配算法.最后,仿真结果显示,与MCM相比,所提出的算法无论是在单天线单信道还是多天线多信道下,都能取得较高的吞吐量和较低的延迟.
Compared with wireless sensor networks and mobile ad hoc networks, wireless mesh networks mainly focus on improving the throughput of multicast, while interference severely limits the network throughput. When building a multicast topology, the minimum cost or shortest path is generally taken into account in the traditional methods, and only a few works have tried to improve the performance by reducing interference. However, they calculate the interference by the method for unicast topology, which is not suitable for multicast. For example if n nodes will receive simultaneously packets from one node, among these n nodes there is interference in unicast, but not in multicast. Therefore this tudy proposes the multicast conflict graph to calculate interference of the multicast topology, and then the concise definition of interference of multicast trees is provided. The study shows that building minimum interference multicast trees (MITs) is a NP-complete problem and proposes a gravitation-based heuristics to approximate such optimal trees. To apply to the environment of multi-channel, the study also proposes the multi-hop channel algorithm (MH) for multicast, which can meet different interference ranges. Simulation results reveal that the algorithms can reduce interference and increase throughput in both single-interface single-channel and multi-interface multi-channel wireless mesh networks.