Cooperation in ad hoc networks: enhancing the virtual currency based models

Cooperation of nodes is a main issue of civilian applications of mobile ad hoc networks. More precisely, mobile nodes with few resources may try to maximize the benefits they get from the network without participating to its services (e.g. without forwarding packets of other nodes). A solution to this problem is to use virtual currency mechanisms: nodes have to pay to send packets and they are rewarded when they forward packets of other nodes. Several papers of the literature have shown that such models enforce individual node cooperation. We address in this paper two main issues of these models that have been left out: the computation by the sender of the price it will be charged and the possibility to reward nodes depending on their charge or resources. We show that it leads to a better load balancing of the network.