The Research Of Duty Cycling For Opportunistic Networks

In the opportunistic networks,the energy limitation of portable devices is one of the important factors that restrict the application of opportunistic networks.It is a very important research topic that how to accomplish the task of cooperative sensing in an energy efficient manner to achieve the goal of lower transmission delay and better data delivery ratio.In this thesis,it is assumed that the inter-contact time between nodes in the opportunistic networks is exponentially distributed and the structure of network is homogeneous.We obtain a reasonable solution formula of duty cycling,and use the calculated duty cycling to design an energy saving mechanism of low duty cycle,named EEALDC,which is under the condition of the expected message delay and message delivery ratio is given.We make a theoretical analysis and experimental evaluation to compare the EEALDC energy saving mechanism with the energy saving mechanism proposed by Biondi E.The experimental results show that the solution mode of duty cycling proposed in this thesis is more accurate than the other solution model,and the energy saving mechanism of EEALDC can effectively save more power energy of mobile devices in opportunistic networks and can get longer network lifetime under the condition of guarantee the message delivery ratio and message delay.In addition,we assume that the mode of network is heterogeneous,propose a more reasonable solution formula of duty cycling for different message forwarding strategies in the condition that the message transmission delay is expected.Through the theoretical analysis and experimental evaluation,we find that the solution mode of duty cycling proposed in this thesis is accurate and it can effectively save the energy of mobile devices in the network.