Hybrid Precoder Design for Angle-of-Departure Estimation With Limited-Resolution Phase Shifters

• Published in: IEEE transactions on communications Vol. 73; no. 6; pp. 4439 - 4453
• Main Authors: Huang, Huiping, Furkan Keskin, Musa, Wymeersch, Henk, Cai, Xuesong, Wu, Linlong, Thunberg, Johan, Tufvesson, Fredrik
• Format: Journal Article
• Language: English
• Published: New York IEEE 2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Accuracy; alternating direction method of multipliers; alternating optimization; angle-of-departure estimation; Antennas; Array signal processing; Beamforming; Communications systems; Electrical Engineering, Electronic Engineering, Information Engineering; Elektroteknik och elektronik; Engineering and Technology; Estimation; Geometry; Hybrid beamforming; hybrid precoder; Millimeter wave communication; Optimization; phase shifter; Phase shifters; Phased arrays; Radio frequency; Signal Processing; Signalbehandling; Teknik; Upper bounds
• ISSN: 0090-6778; 1558-0857; 1558-0857
• DOI: 10.1109/TCOMM.2024.3487517

Hybrid analog-digital beamforming stands out as a key enabler for future communication systems with a massive number of antennas. In this paper, we investigate the hybrid precoder design problem for angle-of-departure (AoD) estimation, where we take into account the practical constraint on the limited resolution of phase shifters. Our goal is to design a radio-frequency (RF) precoder and a base-band (BB) precoder to estimate AoD of the user with high accuracy. To this end, we propose a two-step strategy where we first obtain the fully digital precoder that minimizes the angle error bound, and then the resulting digital precoder is decomposed into an RF precoder and a BB precoder, based on the alternating optimization and the alternating direction method of multipliers. Furthermore, we derive the quantization error upper bound and provide convergence conditions for the proposed algorithm. Numerical results demonstrate the superior performance of the proposed method over state-of-the-art baselines.