Game theoretic analysis of cooperation in autonomous multi hop networks: The consequences of unequal traffic load

Researchers have investigated non cooperative issues in wireless sensor networks and mobile ad hoc networks in the past decade. In particular, packet forwarding is of critical importance in such multi hop networks. This is because there are no preexisting infrastructures. Each node must not only send and receive its own packets but also relay packets to other nodes. However, most work overlooks the fact that the traffic load at the center of the network is significantly higher than at the border when using existing routing protocols. Therefore, a node at the center is requested to forward more packets than a node at the border of the network. This inequality in traffic load can break down many solutions proposed to motivate nodes cooperation. In this paper, we quantify the number of packets a node is requested to forward as a function of its position. We show that, if a load balancing algorithm is not used in a distributed static network, cooperation ultimately breaks down as the number of nodes increases. We support our result by mathematical proofs.