A Research On Balance Between Delivery Ratio And Energy Consumption In DTNs

Delay tolerant networks(DTNs)are type of networks where nodes communicate with other by opportunity.Because of the unpredictable mobility patterns and easily broken connections of nodes,the routing algorithms have always been the focus of research in DTNs.However,there is a few routing works from the perspective of saving energy consumption,so that we research an energy-saving way of data forwarding in DTNs.This thesis introduces the basic concepts about DTNs in the first part of Ch.2.With discussing the model construction and parameter descriptions of DTNs,briefly about the application scenarios of DTNs,and introduces some common network applications of DTNs in recent years.In the next part,the classic routing algorithms and popular research results in recent years are introduced,briefly.In the last part,the simulation experiment method of DTNs is introduced,including the parameters of network performance evaluation and some optimization measures.Through this chapter,a simple complete basic framework of DTNs is established.In Ch.3,to analyze the tradeoff between energy consumption and delivery ratio in DTNs,a mathematical tool name submodular function is used.Its definition and properties are briefly analyzed and introduced.By modeling and analyzing the message forwarding and energy consumption model in DTNs,a submodular optimization expression for DTNs is obtained.This expression can be used to solve the submodular optimal solution of the tradeoff between energy consumption and delivery ratio for DTNs through greedy algorithm.In Ch.4,an energy-saving routing strategy based on the effective interaction degree and utility of nodes is proposed.The network performs forwarding transmission rate control based on the effective interaction degree of nodes.This algorithm can adaptively adjust the trade-off between energy saving and keeping delivery ratio.When the network node judges whether the message is forwarded,the forwarding probability of the message carrier is set based on the node's utility.With this way,a suitable node is selected for message forwarding,which avoids the network from generating too many message copies,at the same time can guarantee the effective delivery of messages.Simulation experiment results show that compared with other routing algorithms,NEIU-EE algorithm can reduce node energy consumption by about 6% ? 15%,and still keep the delivery ratio.