Two-step angle-of-arrival estimation for terahertz communications based on correlation of power-angular spectra in frequency

The future terahertz (THz) communications utilize the frequency range above 300 GHz and can realize a very high data rate. However, one major challenge is the angle of arrival (AoA) estimation because the extremely high path loss requires adaptive high gain directive antennas (e.g. via beamforming). Although, this topic has been comprehensively studied, there is so far no adequate method subject to simple hardware design and computational effort as well as THz channel characteristics. This paper presents an AoA estimation algorithm in two steps based on the correlation of power angular spectra (PAS) in different frequencies. A low frequency radio frequency (RF) frontend is applied for a rough and fast AoA estimation in the first step and the THz RF frontend estimates the precise AoA within the angular range confined in the first step to reduce the time consumption of AoA estimation. The correlation of PAS in different frequencies is the premise of the algorithm and is validated with a broadband channel sounder in a typical application scenario of indoor THz communication. Finally, the algorithm efficiency is analyzed with two exemplar scanning resolutions.