Research On Key Routing Technique For Mobile Ad Hoc Networks

Mobile Ad Hoc networks is a temporary reciprocity networks system including a group of autonomous wireless mobile nodes, it can spread rapidly in the absence of fixed networks infrastructure, and can dynamic reconstruct according to the networks changes, and provide data forwarding services based on multi-hop wireless connectivity. Mobile Ad Hoc networks not only bring great convenience and flexibility for the deployment and application because of total autonomy, distributed networks control and management, but also lead to many negative factors, for example, inter-networks node location and the trust relationship are not stable, the topology change is difficult to predict, frequent route interruption of data transmission, as well as routing reconstruction and maintenance operations with excessive consumption of resources, it is a great challenge for the research and design of the networks protocols.Routing algorithm is the important part in mobile Ad Hoc networks, which is the basis for establishing mobile Ad Hoc networks, however, compared to traditional wired networks routing, routing algorithm of mobile Ad Hoc networks is more challenging, it is a hot issue in the self-organizing networks research. This paper analyzes the inherent characteristics of mobile Ad Hoc networks and the current routing algorithm, and focus on key routing techniques in the self-organized mobile networks environment, which include stable routing optimization based on networks nodes and wireless link uncertainty characteristics, the routing selection techniques of multi-path, load balanced routing technology based on cross-layer collaborative operations, as well as route maintenance mechanisms based on local topology information.By analyzing the dynamic characteristics of mobile node with the degree of uncertainty of its own local topology change, the paper propose a stability measurement algorithm based on local topology changes of entropy measurement, and improve routing discovery mechanism of the dynamic source routing protocols (DSR) on the basis of the algorithm, by choosing networks nodes with relatively stable local topology to establish routing, and improve the stability of the networks routing, thereby inhibiting the rapid growth of the routing protocol control overhead in the dynamic networks environment, improve the overall performance of routing protocols effectively.The quality of the selecting path is important for the performance of routing mechanism in the multi-path routing, the current researches mainly focus on how to find more than one route, the study on specific routing strategy is seldom, we propose a stability measurement algorithm based on the dynamic characteristics of wireless link, which adopt the dynamic characteristics of wireless link as an approximate solution for the stability measurement, avoid the calculation complexity of the routing reliability measurement, and improve the networks performance of routing protocol with the lower control load cost.In the mobile self-organizing networks, uneven load distribution of data transmission will result in the "hot zone", the packet transmission delay increase rapidly, and thus bring wireless link congestion, drop transmitted packets, or even appear networks partitioning due to energy exhaust of heavy load networks nodes. For this problem, we propose an on-demand routing LBBORP protocol with the ability of balanced load, the networks nodes monitor the dynamic changes of data transmission load through cross-layer collaborative manner, and avoid the hot regions by monitoring information in the process of the routing establishing, and balance networks load.The routing of data transmission quickly expire caused by frequent link interruption in Ad Hoc networks, so it requires a strong maintenance mechanisms for routing protocols, the dynamic source routing protocol adopt end-to-end recovery methods not only require a longer response time, but also need to flood a large number of routing control packets, thus seriously affect the overall performance of routing protocol, especially in expansibility. A new adaptive route maintenance mechanism is put forward through combination of active maintenance and passive maintenance, which limit the impact of route maintenance in the scope of partial interruption of the link, it will not only improve the convergence speed of interrupt routing recovery, but also reduce control load increasing caused by the disruption of the link networks, and avoid adverse effects on the normal data transmission for other nodes.