Novel Spectrum Sensing Algorithms for OFDM Cognitive Radio Networks

Zhenguo Shi; Zhilu Wu; Zhendong Yin; Qingqing Cheng

doi:10.3390/s150613966

Novel Spectrum Sensing Algorithms for OFDM Cognitive Radio Networks

Sensors (Basel). 2015 Jun 15;15(6):13966-93. doi: 10.3390/s150613966.

Authors

Zhenguo Shi¹, Zhilu Wu², Zhendong Yin³, Qingqing Cheng^{4

5}

Affiliations

¹ School of Electronics and Information Engineering, Harbin Institute of Technology, 92 Xidazhi Street, Harbin150001, China. shizhenguotvt@gmail.com.
² School of Electronics and Information Engineering, Harbin Institute of Technology, 92 Xidazhi Street, Harbin150001, China. wuzhilu@hit.edu.cn.
³ School of Electronics and Information Engineering, Harbin Institute of Technology, 92 Xidazhi Street, Harbin150001, China. yinzhendong@hit.edu.cn.
⁴ School of Electronics and Information Engineering, Harbin Institute of Technology, 92 Xidazhi Street, Harbin150001, China. cqq@hit.edu.cn.
⁵ Department of engineering, Faculty of Science and Engineering, Macquarie University, North Ryde, Sydeny, NSW 2109, Australia. cqq@hit.edu.cn.

Abstract

Spectrum sensing technology plays an increasingly important role in cognitive radio networks. Consequently, several spectrum sensing algorithms have been proposed in the literature. In this paper, we present a new spectrum sensing algorithm "Differential Characteristics-Based OFDM (DC-OFDM)" for detecting OFDM signal on account of differential characteristics. We put the primary value on channel gain θ around zero to detect the presence of primary user. Furthermore, utilizing the same method of differential operation, we improve two traditional OFDM sensing algorithms (cyclic prefix and pilot tones detecting algorithms), and propose a "Differential Characteristics-Based Cyclic Prefix (DC-CP)" detector and a "Differential Characteristics-Based Pilot Tones (DC-PT)" detector, respectively. DC-CP detector is based on auto-correlation vector to sense the spectrum, while the DC-PT detector takes the frequency-domain cross-correlation of PT as the test statistic to detect the primary user. Moreover, the distributions of the test statistics of the three proposed methods have been derived. Simulation results illustrate that all of the three proposed methods can achieve good performance under low signal to noise ratio (SNR) with the presence of timing delay. Specifically, the DC-OFDM detector gets the best performance among the presented detectors. Moreover, both of the DC-CP and DC-PT detector achieve significant improvements compared with their corresponding original detectors.

Keywords: CP detection; OFDM; PT detection; cognitive radio; spectrum sensing.