Sequential Cooperative Spectrum Sensing Technique in Time Varying Channel

• Published in: IEEE transactions on wireless communications Vol. 13; no. 6; pp. 3394 - 3405
• Main Authors: Prawatmuang, Warit, So, Daniel K. C., Alsusa, Emad
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: adaptive spectrum sensing; Aggregates; Applied sciences; Channels; Cognitive radio; Correlation; Detection; Detectors; Energy use; Exact sciences and technology; Fading; False alarms; Information, signal and communications theory; Monitors; Probability density function; Radiocommunication specific techniques; Radiocommunications; Radios; sequential spectrum sensing; Signal and communications theory; Signal representation. Spectral analysis; Signal, noise; spectrum sensing; Telecommunications; Telecommunications and information theory; Vectors; Wireless communication; Performance evaluation; Time variable channel; Multistage method; adaptive spectrum sensing; Decision support system; Change detection; Measurement sensor; Cognitive radio; Adaptive method; Sequential detection; False alarm rate; Idling; sequential spectrum sensing; Spectrum analysis; spectrum sensing; IEEE standards; Differential method; Signal analysis; Software radio
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2014.051314.131404

Cognitive radio opportunistically accesses the spectrum while the licensed user is idle. A spectrum sensing procedure to monitor primary users' existence is therefore vital to cognitive radios. In this paper, we investigate the energy detection based sequential cooperative spectrum sensing technique in time varying channels. By utilizing past local observations from previous sensing slots, cognitive radio nodes can aggregate the current and previously received energy values to improve the detection performance. We propose the weighted sequential energy detector (SED) in which a fixed number of past observations are taken for decision making. In addition, we propose two adaptive schemes, namely the Two-Stage SED and the Differential SED, where a cognitive radio user uses previously received energy values until it detects a change in primary user's activity. The probability of false alarm and detection for the Weighted SED and Two-Stage SED schemes are derived. The results show that the proposed schemes achieve better detection performance over the conventional cooperative energy detection technique. In particular, the Two-Stage SED and Differential SED schemes can satisfy the IEEE 802.22 standard's requirement of 10% false alarm and 90% detection in scenarios that conventional techniques cannot accommodate.