Polarization information based spectrum detection algorithm for cognitive radio

In this paper, we propose a spectrum detection algorithm based on an orthogonal dual-polarized antenna for cognitive radio, called polarization spectrum detection. In the proposed algorithm, using polarization information from dual polarization received antenna , the test statistic is derived according to likelihood ratio test criteria, and is compared with threshold to detect whether the primary user is present or not. The main new attractive feature of the proposed algorithm is that to work in the presence of unknown priori knowledge. The simulation results show that the proposed algorithm performance with priori knowledge is much better than energy detection, and is affected little by noise uncertainty with unknown priori knowledge.