A centralized method for optimal power allocation in cognitive radio networks

This paper presents a framework for spatial spectrum holes access for the cognitive radio network in the presences of co-channel primary users. The proposed method assumes primary network´s cooperation for its transmitters location and their receptive transmission power. Based on this information, a centralized optimal power allocation to the cognitive transmitters is proposed such that the coverage of cognitive network is maximized. The formulated optimization problem has two constraints: 1) the probability of interference crossing threshold at the primary receivers is within limit, and 2) expected minimum SINR constraint of the cognitive users should be satisfied. Through extensive simulations it is shown that the availability of spatial holes for cognitive transmitters depends on the interference outage threshold for primary users, SINR threshold of cognitive users, and overall coverage of primary network.