Crystallized rate regions in the secondary interference channels

In this paper the problem of sum-rate maximization for secondary cognitive users (SU) in presence of a primary user (PU) transmission is considered. We assume that all of the users are equipped with multiple transmit/receive antennas and that the cognitive users must not induce more interference to the primary users than it is defined in the permissive policy and expressed in terms of a spectrum mask or interference temperature constraint. We employ game-theory to find the so-called correlated equilibrium that corresponds to the playing strategy definitions for all users. Actually, the Vickrey-Clarke-Groves theory has been applied and the regret-matching algorithm has been implemented to find the optimal playing strategy for both secondary users. New cost function has been proposed that allows for fast convergence of the developed solutions to the optimal or sub-optimal point. Extensive simulation results have been carried out to corroborate the correctness of the proposed approach.