Degree of polarization spectrum sensing algorithm for cognitive radios

A new spectrum sensing algorithm-degree of polarization (DoP) sensing algorithm is proposed in this paper. By exploiting a pair of dual-polarized antenna at the receiver, DoP of the received vector signal is estimated and utilized to detect the presence of primary users (PU) based on the polarization characteristics of electromagnetic waves. This method requires no prior information of the PU signals and the channels from PUs to the secondary users (SU). Theoretical analysis of detection probability, false alarm probability and threshold of the proposed algorithm is presented in detail. The theoretical analysis also shows that our algorithm overcomes the noise uncertainty problem. Simulations based on wireless microphone signals considering different SU receiver scenarios are provided to certify the effectiveness of the proposed method. Compared with the energy detector (ED), the maximum-to-minimum ratio eigenvalue (MME) detector and the arithmetic-to-geometric mean (AGM) detector, by applying polarization information signal carries, DoP achieves a better detection performance than AGM, MME and ED with noise uncertainty.