Wide-band Spectrum Sensing for Cognitive Radio by Combining Antenna Signals

T. Betlehem, A.J. Coulson and A.B. Reid

Australian Communications Theory Workshop (AusCTW) 2010  

Abstract—This paper presents methods for enhancing blind spectrum sensing of wide-band signals using multiple antennas on a single cognitive receiver. Regulatory bodies in various countries have found that most radio spectrum is inefficiently utilized. Cognitive radio is a paradigm capable of utilizing bands assigned to licensed or primary users when they are not being used. A critical component of a functioning cognitive radio system is the spectrum sensing of the primary users. We present a hidden Markov model based approach to detecting wide-band signals with multiple antennas, contributing (i) simple means of combining signals across multiple antennas, namely pre-detection combining and post-detection combining, and (ii) a modified hidden Markov model algorithm to detect the interferers from the antenna-combined signals. The designs are characterized using both the dependence of missed detection and false alarm error rates on the Interference-to-Noise Ratio (INR) and receiver operator characteristics.