A hierarchical framework of dynamic relay selection for mobile users and profit maximization for service providers in wireless relay networks

Although extensive research has been carried out on the issue of how to optimally select relays in wireless relay networks, relay selection for mobile users is still a challenging problem due to the requirement that the dynamic selection should adapt to user mobility. Moreover, since the selected relays consume their energy on relaying data for the users, it is required that the users have to pay for this relay service. The price of selecting relays will affect the users’ decisions. Assuming that different relays can belong to different service providers, we consider the situation that the service providers can strategically set the prices of their relays to maximize their profits. In this paper, we jointly study dynamic relay selection for mobile users and profit maximization for service providers. Also, we design a Stackelberg-game hierarchical framework to obtain the solution. At the lower level, we investigate the relay selection problem for the mobile users under given prices of selecting the relays. It is formulated as a Markov decision process (MDP) problem with the objective to minimize the mobile user’s long-term average cost (which consists of the payment to the relay service and the cost due to packet loss), and solved by applying the linear programming (LP) technique. At the upper level, we study the game of setting relay prices for the service providers, with the knowledge that the mobile users will make relay selections based on their given prices. Nash equilibrium is obtained as the solution. Our results can help to provide a guidance for service providers to compete for providing relay services. Index Terms – Relay selection, mobile user, hierarchical framework, Markov decision process, Nash equilibrium.