Research On Mobile Ad Hoc Network Routing Algorithms Based On Geographical Location Information

Mobile Ad Hoc Network(MANET) has the characteristics of dynamic topology, limited bandwidth, etc, and the good routing protocol is the most important issue to establish MANET, which is also the focus and difficulty of the research. Due to the characteristics of the dynamic change of MANET topology, topology-based routing protocols cannot achieve desired routing performance. With the development of positioning technology and the improvement of positioning accuracy, the routing protocol based on geographical location information has become the main research direction of MANET routing protocol.In this thesis, the MANET routing protocols are studied from the perspective of topological structure and geographical location information respectively, and the greedy perimeter stateless routing(GPSR) protocol is mainly further studied. The main contents are as follows:(1). In the view of the possible boundary effect and the best host for greedy forwarding, the angle factor and number of neighboring nodes are considered based on the consideration of distance factor. Then, optimal next hop node is selected according to the decision measurements of neighbor nodes. Specifically, the occurrence probability of boundary effect can be decreased by preferring the node with smaller deflection angle in choosing path. Node with more neighbors is selected to avoid the routing hole as far as possible. The angle, the neighboring node number and residual energy have been taken into consideration to calculate the measurements of neighbor nodes and the optimal next hop node is chosen according to obtained measurements. Nodes with higher energy are preferred, which can effectively avoid the further expansion of the routing hole due to the energy consumption of nodes. The simulation results show that the improved algorithm has better performance in packet delivery ratio, average end to end delay and control overhead.(2). For the phenomenon of temporary communication blindness resulted from periodic beacon(PB) strategy, a dynamic beacon exchange strategy based on fuzzy logic(FLDB) is proposed to improve. The proposed algorithm adopts node moving speed, node residual energy and number of neighboring nodes as evaluation factors and confirms adaptive beacon period using fuzzy logic control mechanism. The adaptive beacon exchange algorithm can increase accuracy and realtime of neighbors table construction and maintenance and provide reliable basis for greedy geographical relay. Simulation results show that compared with PB strategy, FLDB strategy effectively can reduce the phenomenon of temporary communication blindness where the packet delivery ratio, control overhead, and average end to end delay performance indicators have been improved significantly.