Content encounter probability based message forwarding in opportunistic networks

Opportunistic Network is a special kind of mobile Ad Hoc network in which communication nodes are sparsely distributed in the network area and the communicating opportunities between the nodes are created by the moving and encounter of the nodes. Achieving reliable data transmission in Opportunistic Networks is a great challenging task because there is no contemporaneous path between source and destination nodes. In this paper, to achieve more efficient Pub/Sub service, a content-based routing scheme, called Content Encounter Probability based Message Forwarding in Opportunistic Network (CEPMF), is proposed. In CEPMF, predicates are used to propagate the interests of subscribers into the network, and the predicates are tagged with utilities indicating the priority of the node to relay a specific content message. Content messages are transmitted to the nodes with a predicate that matches the content message and has a high utility value. The relay node also merges predicate-utility pairs whose intersection is not empty to improve its buffer efficiency. The evaluation results show that CEPMF outperforms SW and SF scheme by 10% in delivery ratio and by 15% in buffer efficiency.