Physical Layer Secure Transmission Based on Fast Dual Polarization Hopping in Fixed Satellite Communication

A fast dual polarization hopping (FDPH) system is designed to enhance the physical layer secure transmission in fixed down-link satellite communications. In order to prevent the eavesdropper from detecting transmitted signals, a pair of dual polarization states is chosen to carry the modulated signal by the designed FDPH pattern. The polarized signal is transmitted through orthogonal dual polarized parabolic antennas by the virtual polarization technique. Due to the assumption that the designed FDPH pattern is synchronous among the legitimate users, the legitimate receivers apply oblique projection polarization filter to suppress one of dual polarization states, and then have a polarization match to recover the scalar modulated signal and demodulate the scalar signal, whereas the eavesdropper cannot match the right polarization state. Therefore, the eavesdropper receives random amplitudes signal owing to the fast polarization hopping. If the modulation scheme is ASK and quadrature amplitude modulation, the demodulation performance of the eavesdropper would be very poor, resulting in a high bit error rate. Moreover, there is severe distinction in orthogonal dual polarized channel. The legitimate users would have a pre-linear compensation with perfect channel state information, which further worsen eavesdropping. Thus, the eavesdropper cannot even demodulate the phase-shift keying signal because of the time varying orthogonal dual polarized channel and auxiliary polarized angle. Simulation results demonstrate the secure performance of our design.