Study On AODV Routing Algorithm And Relevant Issue In Ad Hoc Network

Mobile Ad Hoc Network is one kind of special wireless mobile network, and its routing design is a hot topic in the field of wireless mobile network.With the continuous progress of manufacturing processes and equipment's performance and with the depth study of basic theory, mobile Ad hoc network started from the applications of military into commercial and civil areas, such as meeting data distribution, digital agriculture, health care,smart highways and so on. So how to further improve the performance of routing protocols is the current important issue that needs to be resolved.The main object of study is AODV in this thesis. Because of its simple and low overhead, it has become a current hot issue. Through the analysis and study about AODV, its own limitation is explored and the solution is given in this thesis.The main achievements of this thesis are as follows:①Some researches on the link detection mechanism of AODV and AOMDV are done. AOMDV which is based on AODV is one kind of multipath extended protocol, and it maintains multiple backup paths.When the primary path fails, backup paths will be used.Both AODV and AOMDV protocols include two kinds of link detection method: HELLO messages detection and link layer (802.11) feedback. In this thesis,comparative analysis researches on link detection mechanism of AODV and AOMDV are done. Experimental results show that the detection of link layer feedback mechanism has higher data packet delivery ratio,lower normalized routing load,higher end-to-end average delay and higher route discovery frequency than HELLO messages in the AODV and AOMDV routing protocols.②Some researches on the local repair of AODV routing protocol are done. The maximum repair length of local repair about AODV is analyzed and studied in this thesis. As for the maximum repair length, the maximum repair length of the original protocol(MAX_REPAIR_TTL) was set as the center, taking seven values respectively. Experimental results show that the greater the maximum repair length is, the higher the data packet delivery ratio is, the greater the normalized routing load is, the longer end-to-end average delay is and the higher the route discovery frequency is; the smaller the maximum repair length is, the lower the data packet delivery ratio is, the smaller the normalized routing load is, the shorter the end-to-end average delay is and the lower the route discovery frequency is. ③AODV routing algorithm is optimized. In this thesis, based on two hop routing information and one hop neighbor information, AODV routing algorithm is optimized, making the AODV protocol automatically adapt to the dynamic changes of the network topology and active routes be optimized dynamically.Experimental results show that the improved protocol has better results than the original protocol in data packet delivery ratio.