Secure Orthogonal Transform Division Multiplexing (OTDM) Waveform for 5G and Beyond

Abstract

In this letter, a secure waveform design for future 5G wireless system is proposed. The developed waveform referred to as secure orthogonal transform division multiplexing (OTDM) waveform, is designed to diagonalize the multi-path channel matrix of only the legitimate receiver (Bob), while degrading eavesdropper&x2019;s reception. In particular, instead of using fixed exponential basis functions, generated by IFFT and FFT as in OFDM, orthogonal transform basis functions, which are extracted from the Bob&x2019;s channel, are utilized to modulate and demodulate the data symbols securely. The simulation results prove that the proposed design provides a significant practical security gap between the Bob&x2019;s and Eve&x2019;s performance. The design is shown to be robust against channel imperfection, and it neither sacrifices communication resources nor considers any knowledge on the eavesdropper&x2019;s channel. Besides security, the scheme results in a higher SNR, leading to a 3-5-dB gain over OFDM at BER &x0003D; <inline-formula> <tex-math notation="LaTeX">{10^{-3}} </tex-math></inline-formula>.