A node scheduling approach in community based routing in social Delay Tolerant Networks

Delay Tolerant Networks (DTNs) also provide the communication to the group of people who carries the mobile devices like smart phone, laptop and palmtop. By exploiting the human characteristics it becomes easy to pretend the social properties which are useful in selecting the appropriate relay node. Many routing protocols have shown the capability of these properties (eg. community and centrality) and improved the performance in terms of delivery ratio and delivery delay. The performance of community based routing protocols mainly depends on the formation of the correct community structure. The admission criteria to add the node in the local community is based on aggregated contact duration or contact frequency between node pair. Until it exceeds the predefined threshold value, node cannot be added in to the local community of each other. Even it is difficult to predict the value of threshold in advance for any data set. By analyzing a community structure at different times, it is found that a community detection similarity is very low in early phase of the simulation. Within the entire network, some nodes are more popular and interact with more nodes than others called hub or central nodes. These nodes play important role in improving the delivery ratio. Hence, we propose the simple approach to schedule the nodes for message transmission based on the two centrality measures: betweenness and degree in the absence of the community information about message´s destination. We validate our proposed scheme using real time traces of two different environments: conference and campus and compared with existing scheme. The simulation results show the higher delivery ratio and low average hop count value for the traces of both the environments.