To meet the ever-increasing data rate demand expected in 6G networks, terahertz (THz) ultra-massive (UM) multiple-input multiple-output (MIMO) systems have gained much attention recently. One notable aspect of these systems is that the deployment of an extremely large-scale antenna array and high transmission frequency result in an expansion of the near-field region where the electromagnetic (EM) radiation is modeled as a spherical wave. In the near-field region, the channel becomes a function of a position of a user equipment (UE) rather than the direction, giving rise to a beam focusing operation that focuses the signal power onto the specific position. However, the traditional approaches relying on the sweeping of discretized beam codewords cannot support this ultra-sharp beam focusing operation in THz UM-MIMO systems. This paper proposes a novel beam focusing technique based on sensing and computer vision (CV) technologies. The essence of the proposed scheme is to estimate the UE’s position from the vision information using the CV technique and then generates the beam heading towards the estimated position. By replacing the discretized and time-consuming beam sweeping operation with a highly precise CV-based positioning, the positioning accuracy as well as the beam focusing gain can be improved significantly. Numerical results show that the proposed scheme achieves significant positioning accuracy and data rate gains over the conventional codebook-based beam focusing schemes.

中文翻译：

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6G 太赫兹通信的视觉辅助定位和光束聚焦


为了满足6G网络不断增长的数据速率需求，太赫兹（THz）超大规模（UM）多输入多输出（MIMO）系统最近引起了广泛关注。这些系统的一个值得注意的方面是，超大规模天线阵列的部署和高传输频率导致近场区域的扩展，其中电磁（EM）辐射被建模为球面波。在近场区域中，信道成为用户设备（UE）位置而不是方向的函数，从而产生将信号功率聚焦到特定位置的波束聚焦操作。然而，依赖于离散波束码字扫描的传统方法无法支持太赫兹 UM-MIMO 系统中的这种超锐波束聚焦操作。本文提出了一种基于传感和计算机视觉（CV）技术的新型光束聚焦技术。所提出方案的本质是使用CV技术从视觉信息估计UE的位置，然后生成朝向估计位置的波束。通过基于CV的高精度定位代替离散且耗时的光束扫描操作，可以显着提高定位精度以及光束聚焦增益。数值结果表明，与传统的基于码本的波束聚焦方案相比，所提出的方案实现了显着的定位精度和数据速率增益。