Millimeter-Wave Communications: Recent Developments and Challenges of Hardware and Beam Management Algorithms

In millimeter-wave (mmWave) communication systems, beam management has been recognized as an essential technique to ensure robust communication links. Recently, as an interest in developing a faster and more accurate beam management algorithm was triggered, various approaches have been devised and theoretically proved. However, most researchers have great difficulty in experimentally demonstrating realistic performance, since implementing the entire system in the mmWave band is another difficult challenge. In this article, we provide a well balanced understanding of those two essential technologies for mmWave communications: hardware technologies for prototyping and signal processing techniques for beam management. This article investigates the recent developments and future challenges to contribute to this active research area. Various commercial state-of-the-art mmWave system hardware components and beam management algorithms are comprehensively classified and compared. Meanwhile, the article provides a demonstration study based on the location-aided beam alignment algorithm by using an mmWave system prototype. Furthermore, we discuss open challenges and some future research directions.