Deadline-sensitive opportunistic utility-based routing in cyclic mobile social networks

A cyclic mobile social network (MSN) is a new type of delay tolerant network, in which mobile users periodically move around, and contact each other through their carried short-distance communication devices. In this paper, we introduce utility-based routing into cyclic MSNs, and propose a deadline-sensitive utility-based routing model. If a message is successfully delivered to its destination before a deadline, its source will receive a positive benefit as the reward. Otherwise, the source receives zero benefit. Also, each message delivery incurs a forwarding cost, no matter whether it succeeds or fails. The utility of a message delivery is defined as the benefit minus the forwarding cost. Under this model, we propose a deadline-sensitive opportunistic utility-based single-copy routing algorithm, DOUR. Each node first determines an optimal forwarding sequence, which is composed of a series of forwarding opportunities, in a distributed and greedy manner. Then, it forwards messages via these forwarding opportunities. Theoretical analysis and extensive simulations prove that DOUR can achieve the optimal utility for each message delivery. Moreover, we extend our algorithm to the case of multi-copy routing, and show that our proposed algorithms can inherently make a good tradeoff among the benefit, delay, and cost for each message delivery.