Research On Friend Community Model-based Routing Algorithm In Delay Tolerant Networks

Delay tolerant networks is a new kind of self-organizing networks with low node density, unstable end-to-end path, low delivery ratio, long delay and so on. In the introduction, it introduces the recently research works, network characteristics and application fields of DTN.Then, in the second chapter, it summarizes the evaluation standard of algorithm performance, some existing routing algorithms and their advantages and disadvantages. Due to the intermittent and uncertain connectivity in DTN, traditional routing algorithms are no longer suitable for DTN, DTN network communication mainly adopt the way of "storage-carry-forward". How the source node choose a appropriate relay node to carry data, and how the data holder-nodes find the destination node or better relay node to deliver data. The key problem is how to deliver the data to the destination node rapidly and effectively.With the spread of 4G and the popularity of smart phones, people dominate the movement of node in the network and endow the node with social attributes. The social attributes contain community, centricity, friendly, similarity, and selfish. The hotspot of research is how to make use of these properties and community to design a new routing algorithm. In the third chapter, it summarizes how to utilize the social structure to express the relationship between the nodes in networks. It also introduces the social attributes and some routing algorithms based on these social attributes.Most forward routing algorithms only consider the relationship between nodes in networks, but the social attributes of the DTN nodes always lead some nodes to visit a geographical communities frequently. In this thesis, according to the history information of node contacting with communities, we define friend communities of nodes, and propose a friend community-based routing algorithm (FCR). In FCR, the source node firstly selects AP of its friend communities and then select node which has contacted with the AP of the friend community of the destination node as the relay nodes to forward the packet to AP of the destination node’s friend communities efficiently. At last, the APs forward the packet to the destination node directly. The simulation results show, compared with Epidemic, Label and SGBR routings, the proposed routing greatly reduce the resource cost under the premise of closing to the maximum delivery ratio obtained by Epidemic algorithm.