A Microeconomic Model for Hierarchical Bandwidth Sharing in Dynamic Spectrum Access Networks

We consider the problem of hierarchical bandwidth sharing in dynamic spectrum access (or cognitive radio) environment. In the system model under consideration, licensed service (i.e., primary service) can share/sell its available bandwidth to an unlicensed service (i.e., secondary service), and again, this unlicensed service can share/sell its allocated bandwidth to other services (i.e., tertiary and quaternary services). We formulate the problem of hierarchical bandwidth sharing as an interrelated market model used in microeconomics for which a multiple-level market is established among the primary, secondary, tertiary, and quaternary services. We use the concept of demand and supply functions to obtain the equilibrium at which all the services are satisfied with the amount of allocated bandwidth and the price. These demand and supply functions are derived based on the utility of the connections using the different services (i.e., primary, secondary, tertiary, and quaternary services). For distributed implementation of the hierarchical bandwidth sharing model in a system in which global information is not available, iterative algorithms are proposed through which each service adapts its strategies to reach the equilibrium. The system stability condition is analyzed for these algorithms. Finally, we demonstrate the application of the proposed model to achieve dynamic bandwidth sharing in an integrated WiFi-WiMAX network.