A game theoretic approach to energy efficient cooperative cache maintenance in MANETs

There have been an increasingly large number of mobile handsets equipped with dual or multiple network interfaces. The server interface (e.g., GPRS, EDGE, UMTS) is responsible for communicating with the network operator, while the peer interfaces (e.g., Bluetooth, IEEE 802.11) are used to connect with other computing devices. However, they are usually used separately. In this paper, we investigate the use of both network interfaces to support energy efficient data applications among mobile clients. Specifically, we proposed a fully distributed protocol for mobile handsets to form cooperative groups to maintain cache consistency with minimal communication with the network operator. Our proposed protocol takes advantage of the low power consumption and high data rate of the peer interface. The aim is to reduce the use of the server interface, which is typically slower and involves higher power consumption. Furthermore, we also consider the presence of selfish clients. It is shown that groups formed by the proposed protocol constitutes a pure Nash equilibrium. This suggests that our protocol is robust even in the presence of selfish clients. Simulation results confirm that, given the same energy resource, mobile clients running the proposed protocol complete more queries, experience longer lifetime and achieve smaller query latency.