Research On Geographic Routing Algorithm Based On Two-hop Nodes'Information In Mobile Ad Hoc Networks

Mobile Ad Hoc Network(MANET)is a multi-hop,non-center,and self-organized wireless network.There is no fixed infrastructure in the network,and each node is free to move,keeping in touch with the other nodes in the network dynamically.MANET has many features such as dynamically changing topology,high-speed mobile nodes,low bandwidth channel and limited capacity terminals.MANET breaks the geographical limitations in the traditional network which can be deployed quickly,easily and efficiently,and it is suitable for the needs of the communication in many situations,such as military applications,sensor networks,emergency and unexpected situations,remote wilderness areas,temporary occasions,etc.Based on those features and applications,it is of great value to research on MANET.The routing in the network layer is a promising research topic.We should take the features of MANET into consideration instead of directly using the existing routing protocols in the wired network.According to the design mechanism,the existing routing protocols in MANET can be divided into two categories:routing algorithm based on topology and routing algorithm based on geographical locations.There is a great possibility of routing holes using GPSR for routing in MANET,and the nearest node to the destination node is not necessarily the optimal forwarding node because of the long distance link,high error rate and the large energy consumption.This thesis presents a geographic routing algorithm based on information of two hop nodes in order to solve the routing holes' problem in GPSR protocol.The routing algorithm is designed by the location information of two-hop nodes and makes decision according to the combination of the minimum angle and the positive smooth path to decrease the generation of routing holes as far as possible.Thus,the packet can be transmitted to the destination node along a smoother path.The simulation has been done in NS2 to compare the routing performance of the DSR,GPSR and GR-BTHNI under different scenarios.Thus,a conclusion can be obtained that GR-BTHNI achieves a lower delay and higher packet delivery rate with the tradeoff of routing overhead expense.Finally,the simulation and performance analysis of GPSR?Greedy-2 and GR-BTHNI are carried out on the two situations one with different node degree and the other with different number of holes in the network.The results show the superiority of the GR-BTHNI algorithm on the performance.