Cognitive Radio Networks with Energy Harvesting

• Published in: IEEE transactions on wireless communications Vol. 12; no. 3; pp. 1386 - 1397
• Main Authors: Park, Sungsoo, Kim, Hyungjong, Hong, Daesik
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Batteries; Cognitive radio; Cognitive radio network; energy causality; Energy consumption; Energy harvesting; Energy use; Exact sciences and technology; Information, signal and communications theory; Mathematical analysis; Networks; opportunistic spectrum access; Optimization; Radio transmitters; Radiocommunication specific techniques; Radiocommunications; renewable energy; Sensors; Signal and communications theory; Signal representation. Spectral analysis; Signal, noise; Spectra; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Thresholds; Throughput; Transmission and modulation (techniques and equipments); Transmitters. Receivers; Performance evaluation; Energy spectrum; Threshold detection; Measurement sensor; Information rate; Transmitter; Cognitive radio network; energy harvesting; Secondary cell; Optimal detection; Information transmission; opportunistic spectrum access; renewable energy; Idling; Energetic efficiency; Spectrum analysis; Analytical method; Electric power consumption; Numerical simulation; energy causality; Causality; Signal analysis; Radio communication; Software radio
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2013.012413.121009

We consider a cognitive radio network with an energy-harvesting secondary transmitter to improve both energy efficiency and spectral efficiency. The goal of this paper is to determine an optimal spectrum sensing policy that maximizes the expected total throughput subject to an energy causality constraint and a collision constraint. The energy causality constraint comes from the fact that the total consumed energy should be equal to or less than the total harvested energy, while the collision constraint is required to protect the primary user. We first show that the system can be divided into a spectrum-limited regime and an energy-limited regime depending on where the detection threshold for the spectrum sensor lies. Assuming infinite battery capacity, we derive the optimal detection threshold that maximizes the expected total throughput subject to the energy causality constraint and the collision constraint. Analytical and numerical results show that the system is energy-limited if the energy arrival rate is lower than the expected energy consumption for a single spectrum access. They also show that a decreasing probability of accessing the occupied spectrum does not always result in decreased probability of accessing the idle spectrum in the energy-limited regime.