Community Detection Using Inter Contact Time and Social Characteristics Based Single Copy Routing in Delay Tolerant Networks

Delay Tolerant Networks (DTNs) where the node connectivity is opportunistic and end-to-end path between any pair of source and destination is not guaranteed most of the time. Hence the messages are transferred from source to destination via intermediate nodes on hop to hop basis using store-carry-forward paradigm. Due to quick advancement in hand held devices such as smart phone and laptop with support of wireless communication interface carried by human being, it is possible in coming days to use DTNs for message dissemination without setting up infrastructure. The routing task becomes challenging in DTNs due to intermittent network connectivity and the connection opportunity arises only when node comes in transmission range of each other. The performance of the routing protocols depend on the selection of appropriate relay node which can deliver the message to final destination in case of source and destination do not meet at all. Many social characteristics are exhibited by the human being like friendship, community, similarity and centrality which can be exploited by the routing protocol in order to take the forwarding decisions. Literature shows that by using these characteristics, the performance of DTN routing protocols have been improved in terms of delivery probability. The existing routing schemes used community detection using aggregated contact duration and contact frequency which does not change over the time period. We propose community detection through Inter Contact Time (ICT) between node pair using power law distribution where the members of community are added and removed dynamically. We also considered single copy of each message in entire network to reduce the network overhead. The proposed routing protocol named Social Based Single Copy Routing (SBSCR) selects the suitable relay node from the community members only based on the social metrics such as similarity and friendship together. ICTs show power law nature in human mobility which is used to detect the community structure at each node. A node maintains its own community and social metrics such as similarity and friendship with other nodes. Whenever node has to select the relay node then it selects from its community with higher value of social metric. The simulations are conducted using ONE simulator on the real traces of campus and conference environments. SBSCR is compared with existing schemes and results show that it outperforms in terms of delivery probability and delivery delay with comparable overhead ratio.