Research On Routing Algorithm And Congestion Control Based On Node Encounter Information In DTN

Delay tolerant network(DTN)is a new type of network that does not have stable end-to-end links.Due to its characteristics such as dynamic changes in network topology,high transmission delay and limited resources,the movement of nodes can not be predicted,and there are few direct links between the source and destination nodes for message transmission.Therefore,the message transmission mechanism of " storage-carry-forward"is adopted among nodes in the delay-tolerant network.The source node carrying the message uses the relay node as the communication medium and finally forwards the message to the destination node to complete the transmission of the whole message.Delay-tolerant network,as a self-organizing network that does not require the existence of stable links between nodes,has great research potential in the fields of aerospace communication,disaster rescue,sensor network and pervasive computing in the future.The design of efficient routing has always been the key content of delay-tolerant network research.The message transmission mode between nodes directly affects the routing performance of network.At the same time,due to the limited network resources,the nodes are affected by the cache space and bandwidth,and the forwarding mechanism of messages between nodes will lead to a large number of messages staying in the cache.The nodes in the network are prone to congestion,resulting in congestion of the whole network.Therefore,the design of reasonable congestion control mechanism is also the focus of delay-tolerant network research.After introducing and analyzing the routing algorithms and congestion control algorithms in delay-tolerant networks in recent years,this paper proposes an improved Spray&Wait routing algorithm based on node historical encounter information and a congestion control algorithm based on message quality and node credibility.Specific research contents and work are as follows:(1)An improved Spray&Wait routing algorithm based on node historical encounter information is proposed.By recording and analyzing the historical encounter information of nodes,this algorithm defines the node stability in the Spray stage by combining the number of nodes in the historical encounter and the historical encounter contact time between nodes,and takes the node stability as the basis for dynamic copy allocation.In the Wait phase,different from the traditional waiting strategy,the node forwarding degree is defined by combining the historical encounter information of the node and the historical encounter information of the encountering node,a node only forwards messages to a relay node that is more forward than it is.(2)A congestion control algorithm based on message quality and node credibility is proposed.By combining message spread in the network degree and the message itself attribute defines the quality,depends on the degree of information quality forwarding and delete the message priority.At the same time,the node credibility is defined by combining the historical encounter information of the node and the node's own attributes,and the node credibility and the remaining cache of the node are used as the basis for the selection of the relay node.(3)Through ONE simulation platform,the improved routing algorithm and congestion control algorithm proposed in this paper are compared with the traditional routing algorithm and congestion control algorithm respectively.The experimental data show that the improved routing algorithm and congestion control algorithm proposed in this paper can greatly improve the network performance.