A Survey of Beam Management for mmWave and THz Communications Towards 6G

TL;DR

This survey reviews beam management techniques for mmWave and THz communications in 6G, highlighting challenges, recent advancements, and future research directions involving AI, RIS, and ISAC technologies.

Contribution

It provides a comprehensive overview of current beam management methods, challenges, and emerging technologies for mmWave and THz communications towards 6G.

Findings

High beam measurement overhead affects beam acquisition and tracking.

AI, RIS, and ISAC offer new opportunities and challenges for beam management.

Future research directions include addressing channel fluctuations and mobility issues.

Abstract

Communication in millimeter wave (mmWave) and even terahertz (THz) frequency bands is ushering in a new era of wireless communications. Beam management, namely initial access and beam tracking, has been recognized as an essential technique to ensure robust mmWave/THz communications, especially for mobile scenarios. However, narrow beams at higher carrier frequency lead to huge beam measurement overhead, which has a negative impact on beam acquisition and tracking. In addition, the beam management process is further complicated by the fluctuation of mmWave/THz channels, the random movement patterns of users, and the dynamic changes in the environment. For mmWave and THz communications toward 6G, we have witnessed a substantial increase in research and industrial attention on artificial intelligence (AI), reconfigurable intelligent surface (RIS), and integrated sensing and communications (ISAC). The introduction of these enabling technologies presents both open opportunities and unique challenges for beam management. In this paper, we present a comprehensive survey on mmWave and THz beam management. Further, we give some insights on technical challenges and future research directions in this promising area.