Optimal Resource Allocation in Simultaneous Cooperative Spectrum Sensing and Energy Harvesting for Multichannel Cognitive Radio

Abstract

In this paper, a simultaneous cooperative spectrum sensing and energy harvesting model is proposed to improve the transmission performance of the multichannel cognitive radio. The frame structure is divided into sensing slot and transmission slot. In the sensing slot, the secondary user (SU) splits the subchannels into two subchannel sets, one for sensing the primary user (PU) by multichannel cooperative spectrum sensing and the other one for collecting the radio frequency energy of the PU signal and noise by multichannel energy harvesting. In the transmission slot, the harvested energy is supplied to compensate the sensing energy loss in order to guarantee the throughput. We have formulated the resource allocation of the proposed model as a class of optimization problems, which maximize aggregate throughput, harvested energy, and energy efficiency of the SU over all the subchannels through jointly optimizing subchannel set, sensing time, and transmission power, respectively. To achieve the sub-optimal solutions to the optimization problems, we have proposed the subchannel allocation algorithm and the joint optimization algorithm of sensing time and transmission power based on the Greedy algorithm and the alternating direction optimization. The stopping criteria of SU is described, when the PU is not present but the harvested energy is not enough. The simulation results are presented to demonstrate the validity and predominance of our proposed algorithms.