Optimal spectrum sensing and transmission power allocation in energy‐efficiency multichannel cognitive radio with energy harvesting

• Published in: International journal of communication systems Vol. 30; no. 5; pp. np - n/a
• Main Authors: Liu, Xin, Jia, Min, Gu, Xue‐mai, Yan, Jun‐hua, Zhou, Jian‐jiang
• Format: Journal Article
• Language: English
• Published: Chichester Wiley Subscription Services, Inc 25.03.2017
• Subjects: Allocations; cognitive radio; Detection; Electric power generation; energy efficiency; Energy harvesting; Energy management; joint optimization; Optimization; Power management; Transmitters
• ISSN: 1074-5351; 1099-1131
• DOI: 10.1002/dac.3044

Summary We consider an energy‐efficiency multichannel cognitive radio (CR) where the secondary user (SU) can harvest the signal energy from the primary user (PU) to supply the power transmission. The goal of this paper is to determine an optimal joint spectrum sensing and transmission power allocation that maximizes the average throughput of the multichannel SU over all the subchannels subject to the constraints of subchannel sensing probabilities, interference power, and total transmission power. The SU harvests the PU energy, which is then converted into electrical energy and stored in the battery if the presence of the PU is detected, while consuming the stored energy to transmit data if the absence of the PU is detected. The allocation scheme is formulated as a joint optimization problem of spectrum sensing time and subchannel transmission power vector, whose optimal solution is obtained through the joint optimization algorithm based on alternating direction optimization. Analytical and numerical results show that the proposed energy‐efficiency CR outperforms the traditional CR without energy harvesting, and the transmission power of the energy‐efficiency CR improves both with the increasing of the spectrum sensing time and the presence probability of the PU. Copyright © 2015 John Wiley & Sons, Ltd. An energy‐efficiency cognitive radio system is composed of energy‐efficiency secondary user (SU) transmitter with primary user (PU) energy harvesting and energy‐unconstrained SU receiver. The SU transmitter accesses the PU spectrum opportunistically when the PU is absent and harvests the radio frequency energy from the PU transmitter when the PU is present. The strategy of periodical spectrum sensing and data transmission is adopted by the SU transmitter, wherein the communication time is divided into several time slots, which are composed of sensing time and transmission time.