Research And Improvement Of Routing In Mobile Ad Hoc Networks

A mobile Ad hoc network is an autonomous system of mobile hosts connected by wireless links. Such networks are useful in military and other tactical applications, e.g., emergency rescue or exploration missions, where cellular infrastructure is unavailable or unusable. In such a network, each mobile node operates not only as a host but also as a router. This network has a series of the strengths, for example: MANET can be built rapidly and easy, and it is not set measures to by wired network, and so on.Because of constantly changing topology, Ad hoc networks can't adopt traditional protocols. Research of routing protocols becomes the most important part of the research of Ad hoc. This paper presents a comparative simulation study of on-demand protocols with the more traditional proactive protocols on a common platform across a range of traffic and mobility scenarios. This simulation cover a range of design choices: AODV, DSR, DSDV, TORA. The simulation results show that on-demand protocols indeed demonstrate low routing overheads, but over-reliance on query flooding can actually cause on-demand protocols to lose most of this overhead advantage at high loads.As a countermeasure, this paper provides two techniques that reduces the routing overhead for on-demand protocols. The first technique is called query localization. It effectively limits the query to a small region where the route is very likely to be found. Simulation results show that the query localization techniques can reduce routing overhead notably. The second technique, called multipath routing, focuses on reducing the frequency of query flooding by exploring multiple, disjoint routes per flood operation. Simulation results show that the technique can reduce routing overheads significantly.At present, the research about Ad hoc network routing protocols has just started, and the routing protocols concerns the key factor whether Ad hoc network could run, So this paper is not merely significant to the research and optimization of the route agreement in mobile Ad hoc network in theory, and also offer scientific basis for its application.