Research On Routing Algorithm Based On Spatial And Temporal Characteristics In Opportunistic Networks

Compared with the traditional network,the opportunistic network of which link is intermittent hardly exists a complete end to end connected path.In addition,the movement of nodes leads to the change of the network topology.This special network environment described above makes the design of routing algorithms face challenges.In order to improve the success rate of message transmission,reduce the transmission delay and network load,it can effectively improve the network performance that using the social attributes of nodes to design the routing algorithm.However,the social attributes of nodes,such as community,centrality,intermediary degree,only reflect spatial connections of nodes(physical space,virtual space),ignoring the relationships between nodes in temporal dimension.Therefore,this article puts forward an activity-based message opportunistic forwarding algorithm(AMOF).The actual network often has community structure,and some communities overlap and interweave,and therefore this paper goes a step further and proposes a message opportunistic forwarding algorithm based on overlapping community(MOFOC).The main content of this paper is as follows:(1)Analysis on the research situation of opportunistic network.The two hot spots in the research of opportunistic network,namely,mobile model and message forwarding mechanism,were reviewed.In addition,the related work of the opportunistic network was classified and described in temporal dimension and spatial dimension.(2)Put forward an activity-based message opportunistic forwarding algorithm(AMOF).Firstly,an activity-based mobile model was designed.The mobile model restores the scene that human participates in various activities periodically.Then,based on the model,an activity-based message opportunistic forwarding algorithm was proposed.By considering the encounter probability of nodes,the encounter period of nodes and the remaining TTL of message,we build message delivery probability which can dynamically evaluate the ability of the node to forward a message to the destination node and guide nodes to forward messages.(3)The design of a message opportunistic forwarding algorithm based on overlapping communities(MOFOC).Firstly,a mobile model based on overlapping communities was designed.The model simulates the mobility of nodes in a network with overlapping community structures.It is found that the communication interval between nodes has temporal heterogeneity and inhomogeneity.Then,we proposed a message opportunistic forwarding algorithm based on overlapping community.The biggest message transmission probability node in overlapping communities is selected to forward message to the destination node,if source node and the destination node both have same overlapping community.While the source node and the destination node do not have an overlapping community,the relay node which belongs to active community of source node is found to forward the message to the active community of the destination node.(4)Simulation experiment and result analysis.Simulation results show AMOF algorithm and MOFOC algorithm can not only improve the success of message delivery,but also reduce the network delay and overhead,compared with classical routing algorithms,such as Epidemic,PRo PHET,CMOT and CMTS.