Feasible solution of power control in the presence of primary user in cognitive radio networks

This paper studies the feasible solution of power control for cognitive radio networks in the presence of primary user. The primary user (PUs) allows the secondary users (SUs) to spatially reuse the spectrum as long as they do not disrupt the communication of the former user. In addition, the primary user is willing to adjust its transmit power to meet the Signal to Interference Ratio (SIR) target, thus allowing the secondary users to achieve their QoS requirement. A feasible solution of power control can be achieved if there is a non-negative transmit power vector P* under constraint of the SIR target of SUs and PU. The simulation results show that the proposed power control scheme based on the feasible solution effectively controls the transmit power of PU and SU transmitters so that each receiver meets the SIR target.