Abstract
Wireless communication services have been increasing rapidly and this progress has caused a shortage in frequency resources. Cognitive radio technology is expected to enable frequency resources to be used more efficiently. This paper will focus on the co-existence between a secondary user and a primary user in order to increase the spectrum utilization by secondary users. We develop an approach to allow the unlicensed user to operate in the presence of the licensed user. Therefore, in order to guarantee the minimum harmful interference to primary users and meeting the Quality of Service (QoS) requirements of secondary users, the transmit power of the cognitive radio is controlled. We focus on the implementation of different power control techniques for Cognitive Radio Networks and simulated results performed using MATLAB, demonstrate the comparative effectiveness of these power control techniques.