A credit-payment scheme for packet forwarding fairness in mobile ad hoc networks

Routing protocols for mobile ad hoc networks (MANETs) have assumed that all nodes voluntarily participate in forwarding others´ packets. This was a reasonable assumption because all nodes in previous MANETs belonged to a single authority. In the near future, however, a MANET may consist of nodes that belong to multiple organizations since various civilian applications are expected to appear. In this situation, mobile nodes may deliberately avoid packet forwarding to save their own energy, resulting in network partition. To make nodes volunteer in packet forwarding we suggest a payment scheme called protocol-independent fairness algorithm (PIFA). In this type of schemes, nodes need credits to transmit their own packets, and this credit can be earned by forwarding others´ packets. PIFA can be utilized irrespective of the type of basic routing protocols, while previous methods are compatible only with source routing like DSR. Simulation results show that PIFA can prevent network partition and network performance degradation due to selfish nodes by inducing them to participate in forwarding packets.