Improving Message Deliverability of Opportunistic Network Protocols

Abstract

Opportunistic Networks (OppNets) are designed to transfer messages between intermittently connected mobile nodes which are unaware of network topology. As the traditional routing protocols, which assume continuous connection between nodes and need to be aware of network topology, cannot be implemented in OppNets, various OppNet routing protocols, such as Epidemic, PRoPHET etc., have been proposed for message delivery. An OppNet's message delivery mechanism is store-and-forward in which a node stores incoming messages and forwards the copies of the messages to nodes it encounters causing a large overhead in the network. Furthermore, as nodes are mobile and are powered by batteries, it is essential to consume less energy and extend the network life so that a large number of messages can be delivered. In order to improve the message deliverability of a node, network overhead and network life expectancy in existing OppNet protocols, we consider the node's resources, whose values change continuously, while transferring messages in the networks. In our proposal, a node first calculates its Message Deliverability (MD) which depends upon the protocol used and its resources. The node then uses its MD and the encountered node's MD to make message forwarding decision. Extensive simulation results have shown that the message delivery probability, network overhead and network life of existing OppNet protocols can be improved significantly using our proposal.  Index Terms-OppNets, message deliverability, routing protocols, overhead, network life Bhed Bahadur Bista received the B.Eng. degree in Electronics from the University of York, England and the M.S. and Ph.D. degrees in Information Science from Tohoku University, Japan. After his Ph.D., he worked at the Miyagi University, Japan, for one year as a Research Associate and moved to the Iwate Prefectural University, also in Japan as an Assistant Professor. Currently, he is an Associate Professor with the Faculty of Software and Information Science at the same university. His research interests include energy efficient networks, mobile networks, sensor networks, ad hoc networks, cognitive radio networks, and cellular networks. He has organized International Workshops and has actively taken part as a Program Chair, a Track Chair and a Program Committee Member in various international conferences including flagship IEEE AINA, NBiS, BWCCA and IMIS. He is a member of IPSJ, IEICE and IEEE.