Cross-Regional Ferry Routing Design for Multiple Messengers in Opportunistic Networks

Opportunistic networks are wireless networks where most of the time there does not exist a complete path between source and destination due to various reasons such as node mobility, wide deployment area, limited radio power, etc. The messages can be forwarded in asynchronous manners, which relies on the contacts between nodes and infrastructures. Ferry routing is an approach which utilizes a set of special mobile infrastructures called messenger to provide communication services for the nodes in opportunistic networks. According to the shortcoming of messengers scheduling and collaboration in traditional ferry routing, a cross-regional multiple messengers scheduling method is proposed in the paper. The network is divided into several horizontal and vertical regions, and each region contains a messenger who provides service for nodes. Messages are forwarded through a single messenger or the collaboration between a horizontal and a vertical messenger. Theoretic analysis of the proposed method at the expected delay is described. The improvement of delay and fault tolerance are also given. Simulation results show that the cross-regional ferry routing not only balances the network load and delay, but also has the capability of tolerancing single messenger fault, and it is a kind of reasonable and efficient multiple messengers scheduling method.