Research On Message Relay Mechanism Of Energy Efficient In Social Delay Tolerant Networks

Social Delay Tolerant Networks(SDTNs) are delay tolerant networks with society which are formed by people with social relationship. Therefore, the study of SDTNs needs to fully consider the characteristics of society and delay tolerant. The node's society is mainly embodied in the community, selfishness, and centrality. The characteristic of delay tolerant is mainly embodied in rare end-to-end connectivity. Since DTN nodes are mostly energy-limited devices, there is an immediate need to have energy-efficient routing protocols, allowing the network to perform better and function longer. Therefore, how to improve the energy efficiency is an important problem of the message forwarding mechanism. In SDTNs, people carrying the nodes form one or more communities with similar interests. And they are generally willing to spend their own resources to forward the message to those in the same community; at the same time, because of social selfishness, they do not want to forward the message to those outside their community, in order to save their storage and energy. Responding improvement of energy-efficient algorithm is proposed in view of the insufficient of existing algorithms and the above characteristics.The system structure and key technologies of SDTNs are firstly researched in this thesis, which lays the foundation for the comprehensive research and analysis of the social delay tolerant network. At the same time, a brief description of some routing algorithms, modeling methods and simulation tools used in the social network is provided, which is a theoretical basis for the following work.Considering social selfishness and energy consumption problems, an ODE model based on multi-community is established. According to the theoretical model, an optimization problem of copy limits is provided. Then the comparison between the results of ONE simulation and theoretical analysis is shown, to verify the accuracy of the theoretical model.Then, two energy-efficient copy-limit-optimized algorithms based on the Box's complex method and ant colony optimization for epidemic routing are proposed. By finding the optimal copy limit vector C*, reducing the delivery ratio, make it close to the transmission demand, to achieve the purpose of improving energy efficiency. At last, the performance of the two optimization algorithms are compared and analyzed by simulation. Besides, the proposed algorithm can effectively improve the performance of the Epidemic protocol, and the influence of social selfishness on the performance of the algorithm is also analyzed.The research in this thesis not only can widely apply to the real world, but also can provide ideas for the research on routing protocols in SDTNs. It has good theory value and application prospect.