Data Dissemination Strategy For Wireless Mesh Networks

Wireless mesh networks(WMN) is an important next-generation wireless network technology, which has characteristics as self-organization, self-configuration and multi-hop. Data delivery strategy plays an important role in WMN, including unicast and multicast, etc. It is an important research topic to design efficient data dissemination strategy(data transmission strategy) for WMN by taking advantage of WMN’s relative complete mesh topology, combined with the specific characteristics of its network type.This paper improves the data distribution strategy of IEEE 802.15.5 based WMN by overcoming its shortcomings. The main work is as follows:1. In the unicast strategy of IEEE 802.15.5 WMN, referred to as the basic scheme below, when the destination node is not within one of the address blocks of the neighbors of the current node, the current node searches an anchor node in its neighbors that has the property of minimum sum of tree level and the number of hops between the anchor, and then the next hop is found starting from the anchor. There is a drawback in the anchor selection scheme, i.e., a route with low reliability in spite of fewer number of hops is probably chosen in data delivery. To overcome this problem, the improved data deliver scheme is presented in this paper, which chooses Expected Transmission Count(ETX) as the weight of a wireless link such that the ETX of the route is reduced. Simulation results show that, the proposed scheme outperforms the basic scheme in terms of ETX while the numbers of hops of data delivery route in both schemes are close.2. For current multicast strategy of IEEE 802.15.5 WMN, this paper improves the multicast tree building process. The most critical issue for multicast protocol in IEEE 802.15.5 is to build a multicast tree cover all multicast group members. On one hand, the multicast tree construction is closely associated with members’ join process and the return path of G-JREP(group-join reply) command frame will become the new branch of multicast tree, the process of which relies on unicast protocol. This paper uses the improved unicast protocol proposed in this paper to replace the original algorithm so that the multicast tree select paths with higher communication quality as its new branches. Thus, the average transmissions to successfully multicast packages is reduced. On the other hand, the multicast tree’s shape affects the average distance from the source to all the destinations and the shape of multicast tree original built is often not the best. So this paper proposes an adjust strategy of multicast tree which is suitable in the case that group members are relatively stable. It can effectively reduce the average hops from the source to other multicast group members and the longest path’s hops between them that determines the maximum delay in multicast.