Power control for cognitive users in coexistence with CSMA-based primary networks

Cognitive radio networks are an emerging paradigm for intelligent networks to resolve the spectrum under-utilization problem, as they allow cognitive users to utilize frequency bands assigned to primary users. In this paper, we consider the transmit power control of a secondary transmitter when a primary user accesses a wireless channel through a carrier sense multiple access (CSMA) mechanism. In this case, the transmit power of the secondary transmitter should be adjusted in order to prevent the transmissions of the primary user from being deferred under the CSMA mechanism.