A dual-polarized antenna based sensing algorithm for OFDM signals in LTE-Advanced systems

In this paper, a new spectrum sensing algorithm-variance of polarization distance (VoPD) sensing algorithm is proposed based on the frequency-dependent polarization characteristics of orthogonal frequency-division multiplexing (OFDM) signals. With a pair of dual-polarized antenna (DPA) deployed in Long Term Evolution Advanced (LTE-Advanced) system, the orthogonal polarization components of the received signal are obtained, and VoPD is estimated to detect the presence of licensed users. Since VoPD is a frequency-domain detection algorithm, it leverages the relatively stable frequency-dependent polarization feature of the received OFDM signal, and is designed to exploit the polarization-sensitive impairment, Polarization Mode Dispersion (PMD). It is a natural expansion that we further extend the frequency-domain detection statistics to that in time-frequency domain to further improve the detection performance. Finally, theoretical performance analysis and comprehensive simulations based on OFDM modulated DVB-T signals are demonstrated to show the effectiveness of VoPD detector.