A power control protocol to maximize the number of common available channels between two secondary users in cognitive radio networks

Cognitive radio is a promising technology that can improve the utilization of the spectrum. In a cognitive radio ad-hoc network (CRAHN), a secondary user (SU) has to get its available channels by sensing the spectrum, and two SUs should rendezvous on a common available channel to realize communications. Therefore, the number of the common available channels is an important factor for a SU pair. However, all the existing papers in CRAHNs focus on directly using the common available channels to design efficient algorithms for rendezvous, broadcast, and spectrum handoffs. They did not consider improving the performance from the perspective of increasing the number of common available channels. In this paper, we first analyze the relationship between the SU transmission power, sensing threshold, sensing range, and the number of common available channels. Then, we propose an optimization model to obtain the optimal transmission power of a SU sender. Based on the optimal transmission power, we propose a power control protocol which can maximize the number of common available channels between two SUs. This protocol is practical and easy to implement. Simulation results show that our proposed protocol can efficiently improve the throughput of the communication between two SUs under different scenarios. To the best of our knowledge, this is the first work that considers improving SU performance via maximizing the number of common available channels.