Research On Wireless Sensor Cache Management Strategy Based On Opportunistic Network

Opportunistic Network is a new type of wireless ad hoc network,derive from Delay Tolerant Network(DTN),which is a new research direction of DTN network.No stable link exists in The Opportunistic Network,and the information transmission between nodes comply the mode "Store-Carry-Transmit".Hence a message always saves several duplicates at different nodes during the process.However,the cache resource is limited,and this kind of delivery mode will lead to the rapid depletion of node' cache resource,and then affect the subsequent transmission directly.Designing an efficient cache replacement strategy is significant for improving the overall performance of the network.In view of this issue,this paper summarize the concepts,characteristics,core technologies and application scenarios of Opportunistic Network,and analyzes the practical problems.According to the problem that the node can not sense the number of duplicates that a message saved in the network,this paper proposes the method of maintaining the full list of messages(MT)at each node,which could grasp the numbers in time.And then it uses the optimization method to find out relationship between the amount of duplicates and the three indicators of the overall performance of Opportunistic Network,combines the energy consumption perception factors,finally puts forward a new multi-index cache replacement strategy.Simulation experiment was employed by using the Opportunistic Network simulation platform ONE.Compared with the traditional Opportunistic Network cache replacement strategy' performance,the simulation results suggested that the proposed multi-index cache replacement strategy has a significant improvement in message delivery rate,average transmission delay and network average cost.