Research Of Opportunistic Forwarding Based On Node Centrality And Boundary Box

With the rapid development of network communication technology,while the quality of communication has been improved,the mobile terminal devices integrated with a variety of applications also enrich the amateur life of users.However,in some special application scenarios,the communication infrastructure is not well-constructed or even destroyed,such as outer space,disaster scene,outdoors and underwater,etc.,which can not directly establish the end-to-end links between mobile devices.In order to meet the communication requirements of these scenarios,it is necessary to adopt a communication mode that supports intermittent data forwarding,that is,an opportunitic forwarding mode.In the opportunitic forwarding,the nodes move frequently,and they can't keep the end-to-end paths all the time,which requires other nodes help them complete the communications by multi-hop transfers.Therefore,the key stage in the design of forwarding strategy is to select the next hop node and then forward the carried messages.Specifically,the attributes such as neighboring node location,destination node location and node moving speed are changing over time,which can be taken as the main basis for selecting the next hop nodes.In order to reduce the forwarding resource consumption and transmission delay,the primary goal of forwarding strategy is to improve the delivery ratio of messages as much as possible.The nodes in social delay tolerance network are very uneven,and they usually prefer to move to the office buildings,apartments,shopping malls and other building areas,so the nodes in these areas are densely deployed,while the nodes in other areas such as the roads between buildings are sparsely deployed.In order to improve the transmission efficiency of the network,a mixed message forwarding algorithm(MMF)based on node centrality and community delivery box is proposed.The algorithm differentiates the message forwarding methods in the communities and outside the communities.In the same community,the differences between node centralities and node movement directions are used to improve the message forwarding.In addition,a boundary box is set up in the sparse area of nodes.Each boundary box is considered to be a network node with fixed location and a large storage space,which can forward the messages between neighboring communities.Simulation results show that the proposed MMF has a preferable message delivery ratio and a short transmission delay.MMF algorithm can be used to promote the message forwarding of mobile terminals.MMF also has some shortcomings,which need to be further improved in the future work,such as the design of node centric utility value,community division,some parameter settings of delivery box and so on.