Non-cooperative behaviors in communication networks can significantly adversely affect the entire network. The WWAN/WLAN two-hop-relay system (Wei, H.-Y. and Gitlin, R.D., 2004) integrates two types of wireless technologies to improve wireless access throughput and coverage. Relay nodes in the two-hop-relay system can be wireless relay routers deployed by wireless service providers, or dual-mode users who voluntarily relay traffic for other users. However, it is likely that all dual-mode terminals are selfish and are not willing to relay for other users without an incentive. We propose a proper scheduling algorithm as an incentive mechanism for the hybrid wireless relay network. We use the basic concepts of game theory, especially the Nash equilibrium concept, to design our scheduling algorithms. Several scheduling algorithms, including the maximum rate C/I scheduler, the proportional fair scheduler, and the round robin scheduler, are examined to understand performance while operating under the assumption that all users are selfish. Under the C/I scheduler or the proportional fair scheduler, Nash equilibriums exist at the operating points where no user relays for other users - an undesirable situation. Under the round robin scheduler, selfish users are indifferent on relaying voluntarily or not relaying. Therefore, we are inspired to design a novel incentive scheduling algorithm to encourage relay. By applying the proposed incentive scheduler at the base station, all selfish users relay cooperatively at the Nash equilibrium.
['Hung-Yu Wei', 'Richard D. Gitlin']
Incentive scheduling for cooperative relay in WWAN/WLAN two-hop-relay network