Research On Urgent Communication Based On Wireless Mesh Network And Improvement Of AODV

The Wireless Mesh Networks (WMN), also known as multi-hop wireless networks. It is a cutting-edge network technology different with the traditional network completely. WMN has much good characteristics, such as large capacity, high speed, easily to configure, etc. WMN is becoming an effective tool to complement broadband wireless access, and could apply to kinds of wireless environment flexibility. WMN is one of the key technologies to solve "the last mile" problem.The flexibility, easily to configure, widely coverage and other characteristics of WMN determine that it can be applied to such as earthquakes, snowstorms and other similar communications circumstances under emergency. In this paper, after analyze the features of communication environment under traditional emergency situations, proposes that adopt WMN in the initial disaster emergency communications circumstances, providing network access for users if base stations and other communication infrastructures are destroyed. In this paper, two typical network topologies structure are designed which could be applied to the emergency conditions, and using NS2 simulate the specific properties of different network topologies, including end to end average business throughput, end to end average delay, packet delivery ratio. The impact of different operations such as business configuration and different topologies on network performance is discussed in detail according to the simulation results. Respective application areas of different topologies are pointed out according to the simulation results finally.Routing Protocol is one of the most hot research areas in WMN. The common routing protocols are analyzed, and select the classic AODV (Ad hoc On Demand Distance Vector) as the basis to improve in this paper. This paper proposes a maximum lifetime improved AODV routing protocol based on reply messages (LAODV), to cope with the routing interrupted frequently accompany with nodes move in network.In initial phase of the routing found in LAODV, a routing broadcast node will broadcast its own mobile messages to the neighbor nodes, and the neighbor nodes will compute the routing lifetime combine with their owns after mobile information from the routing broadcast node are received. After the lifetime are calculated, the nodes then send back to the routing broadcast node. So, the maximum lifetime routing are selected, avoiding the routing performance decrease along with the routing interruption caused by the mobile nodes move frequently. Simulation analysis shows that LAODV could establish a better routing than the traditional AODV routing protocol to a certain extent.Finally, the completed research work is concluded and the future research work is prospected.