Reseearch Of Routing Algorithms In Delay Tolerant Network

Delay tolerant network (DTN) is a new kind of network architecture, which can communicate in some challenging networks with large delay and frequently intermittent connectivity. The network architecture which arises in various contexts, such as vehicle network, wildlife monitoring, deep space exploration, rural communication and military battlefield network, is very valuable for both theoretical research and practicability. Due to the dynamic of DTN topology, link interrupt may be more frequent than connection, and a continuous end-to-end path may not exist in a certain period of time. So research of routing problems in DTN is a challenging task.This thesis focuses on routing problems in DTN. At first, it gives an account of research background, characteristics, network architecture, research status, application prospect and challenges in DTN. Then the routing algorithms in DTN are analyzed. And we give the depth research on the issue of routing algorithms in DTN, which is on the basis of the existing research. The main research results include:1) According to the low data transmission rate of routing algorithms in DTN, a DTN routing algorithm, which dynamically adjusts the probability of forwarding and the correction factor of probabilistic forwarding between nodes through the historical information of the time interval and the transmission of probability between nodes met, is proposed based on the probability of self-correction forwarding. Simulation results show that the algorithm has better pertinence and accuracy in the choice of forwarding nodes and has better performance than other similar algorithms.2) That a routing algorithm based on the visiting area in DTN is proposed by making use of the number of nodes visiting area and the transmission of probability of visiting area between nodes. And a rational mobile model for nodes is designed. The algorithm, which can calculate the probability between nodes in the whole area through the number of nodes visiting area, improves the performance of network transmission and effectively controls network overhead. Simulation results verify the effectiveness of the routing algorithm at last.3) On the basis of the MobySpace thought, a routing algorithm which bases on the space distance in DTN combining with the Euclidean distance formula is proposed. The whole area is regarded as a n-dimension space and the number of nodes visiting area as coordinate. Then space distance between nodes is calculated through the coordinate of nodes. Using this method, DTN enhances accuracy in the choice of forwarding nodes, so as to realize the forwarding of messages. Simulation results show that the algorithm enhances pertinence and accuracy in the choice of forwarding nodes and improves the success rate of data transmission.