Research And Implementation On Unidirectional Link Problem Of AODV Protocol In Ad Hoc Network

Mobile Ad hoc network is a kind of network architecture which is composed of a group of wireless mobile nodes. This kind of network is independent of existing communication network infrastructure, and could be self-organized more rapidly and more flexible. It is characterized of self-organization、self-cure、no central entity and etc. Because of such characteristics, ad hoc network has a wide range of application prospect, and so far, it has been widely used in many occasions such as disaster recovery、military operations、private network and so on.As the specificity of ad hoc network, its routing protocols are different from traditional Internet routing protocols. The routing protocols of ad hoc network can be divided into two kinds; one is Table Driven Routing Protocol, also could be named as Proactive Routing Protocols, in which nodes in network should maintain routing tables to store routing information, such as DSDV routing protocol; another is on-Demand Routing Protocol, in which a routing process would be initialized only when the source node demand to do, such as DSR and AODV routing protocols. We could do some qualitative analysis to assess the performance of routing protocols on such aspects, including whether the protocol is distributing、whether it is open-looped、whether unidirectional link is supported、network security and so on. Unidirectional link problem is that, unidirectional link would be always existed in wireless network, in ad hoc networks, links are always assumed as bidirectional when routing protocols are designed, but in fact, some protocols could not work normally in unidirectional link scenarios.In this passage, a description of ad hoc network is made firstly, including the concept、characteristics and some other aspects of the network. Then AODV protocol in Ad hoc network is depicted in detail, some analysis on unidirectional link problem in this protocol is made, and then solutions and problems on this problem still existed in this protocol are analyzed. In the third part, two additional solutions are given for unidirectional link problem, and some simulations are made also. In the next part, the implementation of the improved AODV protocol is described in brief. At last, summary of the essay of the essay, and some problems to be resolved and the research direction are put forward.