Communicating on millimeter wave (mmWave) bands is ushering in a new epoch of mobile communication which provides the availability of 10 Gbps high data rate transmission. However, mmWave links are easily prone to short transmission range communication because of the serious free space path loss and the blockage by obstacles. To overcome these challenges, highly directional beams are exploited to achieve robust links by hybrid beamforming. Accurately aligning the transmitter and receiver beams, i.e. beam training, is vitally important to high data rate transmission. However, it may cause huge overhead which has negative effects on initial access, handover, and tracking. Besides, the mobility patterns of users are complicated and dynamic, which may cause tracking error and large tracking latency. An efficient beam tracking method has a positive effect on sustaining robust links. This article provides an overview of the beam training and tracking technologies on mmWave bands and reveals the insights for future research in the 6th Generation (6G) mobile network. Especially, some open research problems are proposed to realize fast, accurate, and robust beam training and tracking. We hope that this survey provides guidelines for the researchers in the area of mmWave communications.
翻译:在毫米波(mmWave)波段上进行通信正在迎来一个新的移动通信时代,它提供了10千兆字节高数据率传输的机会。然而,由于空间路径严重丢失和障碍阻塞,千兆字节连接很容易发生传输短距离通信。为了克服这些挑战,正在利用高度定向的光束来通过混合波束形成牢固的联系。精确地调整发射机和接收机光束,即波段培训,对于数据率高的传输至关重要。然而,它可能造成巨大的间接费用,对初始访问、移交和跟踪产生消极影响。此外,用户的移动模式复杂而动态,可能导致跟踪错误和大规模跟踪。高效的波束跟踪方法对维持稳健的连接产生了积极的影响。本文章概述了毫米波段的光束培训和跟踪技术,并揭示了第六代(6G)移动网络未来研究的洞察力。特别是,一些公开的研究问题可能会对初始访问、交接和跟踪产生消极影响。此外,用户的流动模式复杂而动态,可能导致跟踪错误和跟踪。我们希望高效的波段跟踪方法能对维持稳健的连接产生积极影响。我们希望这一区域研究人员能够进行这一调查。