Spectrum Sensing in Multi-antenna OFDM System for Cognitive Radio Networks ⋆

This paper proposes an efficient spectrum sensing scheme for OFDM signal transmitted by the primary user with its Cyclic Prefix Correlation Coefficient (CPCC) based on multi-antenna. Inspired by the Maximum-minimum Eigenvalue Detection (MMED) algorithm, a CPCC-based MMED spectrum sensing algorithm is proposed. This algorithm uses inherent property of Cyclic Prefix (CP) resulting in nonzero correlation of the received OFDM primary signal. The maximum-to-minimum eigenvalue ratio of the covariance matrix of the received primary signal is used as a test statistic to detect signal existence. Based on the random matrix theory, we obtain the quantification of the detection ratio, threshold and probability. Finally, the performance of the algorithm is studied through computer simulations. A comparison of the proposed CPCC-MMED algorithm with MMED and ED algorithms is also carried out.