Orthognal Precoding Based on the Prolate Spheroidal Matrix

The security guarantee of the traditional communication method is based on cryptography. In contrast, Transform Domain Communication System (TDCS) preprocesses the transmission waveform, so that the waveform transmitted on the channel changes significantly. In this paper, we explore a new preprocessing method based on TDCS, which can maintain accuracy and improve security. Our simulation system is based on Orthogonal Frequency Division Multiplexing (OFDM) and multipath Doppler channel model. First, we use the mutually orthogonal nature of Prolate Spheroidal Wave Functions (PSWF) to construct the prolate spheroidal matrix. And then we use this matrix for preprocessing. Finally, by comparing the constellations before and after preprocessing and the bit error rate under the same Signal-to-Noise Ratio (SNR), we believe that orthogonal precoding based on the prolate spheroidal matrix can improve security while maintaining accuracy.