Patient Routing in the Delay Tolerant Networks

Abstract

Delay Tolerant Networks (DTNs) are unstable networks, where contemporaneous end to end paths don’t exist. This leads to the problem of how to route a packet from one node to another in such a network, involving whether to send a packet, when to send it and the energy consume control. The existing literature mainly focuses on the energy consumption of packet routing to a single destination node, seldom considering the influence of optimal choice about transmitting rate on network performance. The paper addresses this problem by modeling the packet delivery process of DTNs with multiple destinations adopting ordinary differential equations (ODEs). Furthermore, the tradeoff between delivery performance and energy consumption during packet delivery are mathematically characterized, proving that the maximization of tradeoff is a submodular function and an NP-hard problem. Then, an optimal control method called ‘patient routing’ is proposed to decide whether to send a packet and when the best time is through transmission probability and transmitting rate judgments. Before that time, the node will wait patiently. Our simulations reveal that the proposed routing can significantly reduce nodes energy consumption and achieve higher tradeoff over the other three routings.