Continuous power allocation strategies for sensing-based multiband spectrum sharing

We propose continuous power allocation strategies for secondary users (SUs) based on sensing the primary user (PU) channels in a multiband cognitive radio (CR) network. Unlike the conventional sensing-based spectrum sharing, where there are two transmit power levels corresponding to whether the PU is sensed present or not, in the proposed strategy, the power levels are continuous functions of the sensing statistics, and optimized with respect to the achievable rate of the SU. The power control process consists of two phases: in the first phase, the SU listens to the multiple bands licensed to the PU and obtains the received signal energies on these bands; in the second phase, the SU adjusts its transmit power levels on these bands based on the sensing results. Simulation results demonstrate that the proposed strategies can significantly improve the achievable throughput of the SU compared to the conventional methods.