A hierarchical caching game for message relaying in delay tolerant networks

The mobile nodes in delay tolerant networks communicate with each other using a store-carry and forward mechanism even though there is no permanent link between the source and the destination. This mechanism requires cooperation between nodes. However, because of limited resources such as storage and energy, most of the nodes act in a non-cooperative way. In this paper, an incentive mechanism is proposed to encourage messages caching in DTNs. The source offers a reward to the relays to incite them to participate in delivering the message to the destination. We model the interaction between the source and the relays as a Stackelberg game in which the source takes the role of the leader and the relays respond based on the leader's move. Also, two different learning algorithms are presented: one for the leader, the other for the followers, to allow them to take the best decision and finally, to converge to the Stackelberg Equilibrium.