White space ecosystem: A secondary network operator's perspective

The successful deployment of a TV white space network requires the coordination and cooperation of all involved parties (including licensees, databases, secondary operators, and end-users), which form the White Space Ecosystem. In this paper, we study the white space ecosystem from the perspective of secondary network operators. Specifically, we consider a competitive white space network, where multiple secondary operators compete for the same pool of end-users. Each operator serves the attracted end-users by using either the dedicated spectrum (pre-ordered in advance) or the shared spectrum (requested in real-time). The key problem for each operator is to (i) determine the order quantity of dedicated spectrum, considering the uncertainty of end-user demand, and (ii) decide the price to the end-users, considering the competition of other operators. We formulate the interaction of operators as a non-cooperative Price-Quantity competition game (PQ-game), and study the existence and uniqueness of the Nash equilibrium (NE) systematically. We further characterize the impacts of the operator competition on the social welfare and the operators' own profits. Our results show that such impacts depend largely on the operators' cost of purchasing spectrum from the database or licensee: when the cost is low, the operator competition will decrease the social welfare and the operators' profits; when the cost is high, however, the competition will increase the social welfare and the operators' profits.