Enhanced physical layer security by OFDM signal transmission in fractional Fourier domains

The main idea of physical layer security for wireless communications is making the transmitted signal as meaningless for eavesdroppers. It can be achieved by signal processing techniques. In this study, fractional Fourier transform is used for secure communication. Transmitted signal is divided to equal and random intervals, then each interval was taken fractional Fourier transform with four degrees. In this way, signals can be transmitted with an angle between time and frequency domain. Receiver needs to know which angular parameters are used in each interval for obtaining the signal correctly. It is difficult to obtain signals by eavesdropper without any parameter knowledge. In this study, the bit error rate performances of legitimate users and eavesdropper are compared and the bit error rate performance of eavesdropper becomes close to 0,5.