Performance comparison of equalization techniques for indoor THz communications

Abstract

THz communications is one of the candidates for future ultra-fast wireless transmission. However, the peculiarities of propagation in the THz band result in a highly frequency-selective channel and a much longer channel impulse response (CIR) compared to that of a wireless microwave channel. In this paper, an indoor single-carrier THz transmission is studied. To this end, the following equalization approaches are considered: Tomlinson-Harashima precoding (THP), a waveform design with interference management for time-reversal signaling, and an iterative algorithm with adaptive soft feedback. The iterative algorithm was originally designed for binary transmission and is extended to QAM modulation. A common framework is developed to compare the performance of the different equalization methods. Simulation results support the feasibility of the investigated equalization schemes for coping with the frequency selectivity of the THz band in an indoor environment.