Opportunistic Spectrum Access with Hopping Transmission Strategy: A Game Theoretic Approach

This paper presents a study on opportunistic spectrum access for secondary users (SUs) from a game-theoretic learning perspective. In consideration of the random return of primary users, it is assumed that a SU dynamically hops over multiple idle frequency-slots of a licensed frequency band, each with an adaptive activity factor. The problem of finding optimal activity factors of SUs is cast in a game-theoretic framework and is formulated as a potential game. Subsequently, the existence, feasibility and optimality of Nash Equilibrium (NE) are investigated analytically. Furthermore, an algorithm is developed in which each SU independently adjusts its activity factors based on the best response dynamics by learning other SUs´ behavior from locally available information. Aiming to establish stability for the proposed algorithm, the convergence with probability 1 to an arbitrarily small neighborhood of the globally optimal solution is investigated with analysis and simulation.