Research And Comparison Of Routing Algorithms Based On Multiple Strategies In Delay-tolerant Networks

Delay tolerant networks(DTNs)are a type of newly proposed network that characterized by intermittent connectivity,frequent partitions,high latency,etc.Therefore,nodes in DTN communicate in a “store-carry-forward” manner.Currently,how to make more efficient routing selection becomes a hot topic in DTNs.This paper mainly studies the two aspects of the relay node selection mechanism and the message data management mechanism,and studies how to design an efficient routing algorithm which is more suitable for DTN.The main contents include the follows:(1)On the base of analyzing the shortcoming of the Spray and Wait,an adaptive routing based on node performance and encountering probability is proposed,which consists of two phases.In the spray stage,by considering node throughput,we define an absorbing metric to select a better node as the next relay node.We also define another node activeness metric to asymmetric allocate copies.In the wait stage,the statistical method is used to estimate node encounter probability.This function can transfer message copies in target region.(2)On the basis of the analysis of the different responsibilities of the message source node and the message relay node in the communication process,we propose a location position and message delivery ratio based controlled Epidemic routing for DTNs,which adopts different strategies on the message source node and relay node.On the message source node,the local position information is used to control the spread of the message.On the relay node,we use various kinds of utility information to filter out the best node for the message replication,which can better control the message redundancy.(3)We combine node's selfishness attribute and moving patterns so as to achieve fast directional transmission of message.By taking into account message's delivery probability and priority,we define a message forwarding profit as the optimal target and further model message management mechanism as a 0-1knapsack optimization problem,which solved by the dynamic programming technique.Simulation results prove the efficiency and reasonability of the work in the thesis.The proposed three algorithms achieve great performance in message delivery ratio,network overhead.Thus significantly improving the routing transmission performance.