Optimal simultaneous cooperative spectrum sensing and wireless power transfer with power splitting in multichannel cognitive radio network

In cognitive radio network, the secondary users (SUs) perform cooperative spectrum sensing (CSS) to improve the sensing performance when the primary user (PU) is shadowed or in severe fading. However, the CSS may deplete some electric power including sensing power and cooperative power, thus yielding to decrease the transmission power. In this paper, a simultaneous CSS and wireless power transfer (WPT) is proposed by using a power splitter to split the received PU signal into a harvesting signal stream and a sensing signal stream. The sensing signal stream is used to perform CSS, while the radio frequency energy of the harvesting signal stream is converted into the electric power to supply the CSS simultaneously. A joint optimisation problem of sensing time, cooperative SUs and power splitting is formulated, which seeks to maximise the total spectrum access probability of the SU over all the subchannels, subject to the constraints of the detection probability, the harvested energy and the number of cooperative SUs. The simulation results have shown that the proposed simultaneous CSS and WPT can improve the transmission energy compared with the traditional CSS, and there is a trade-off between spectrum access and energy harvesting. Copyright © 2015 John Wiley & Sons, Ltd.