# Experimental Studies on Low-Latency RIS Beam Tracking: Edge-Integrated and Visually Steered
###### Abstract  
In this study, to address the problems of high feedback latency and redundant codebook traversal in traditional Reconfigurable Intelligent Surface (RIS) beam tracking systems, two novel experimental schemes are proposed: the Edge-Integrated RIS Control Mechanism (EIR-CM) and the Visually Steered RIS Control Mechanism (VSR-CM). The EIR-CM eliminates the feedback latency of the remote server and optimizes the local computation by integrating the RIS control system and the User Equipment (UE) into the same edge server to reduce the beam tuning time by 50%. The VSR-CM realizes beam tracking based on visual perception, and directly maps the UE position to the optimal RIS codebook with a response speed as low as milliseconds. Experimental results show that the EIR-CM reduces the RIS feedback latency to 1-2 s, and the VSR-CM can be further optimized to less than 0.5 s. The two mechanisms are applicable to 6G communications, smart transport, and drone networks, providing feasibility verification for low-latency and efficient RIS deployment. reconfigurable intelligent surface; edge-integrated; visually steered; low-latency optimization; beam tracking 2025 222-2242-1/1  
In [10], a hierarchical codebook tracking scheme was investigated, where a coarse-grained codebook is first used for an initial scan to quickly determine the general direction, followed by a fine-grained codebook for precise adjustments. This approach reduces traversal time and enhances beam optimization efficiency. In [11], the problem of beam training in 6G space-air-ground integrated networks was studied, and a hash-mapping-based beam training scheme was proposed to improve the efficiency of RIS codebook selection. Additionally, the authors of [12] proposed a dynamic scatterer tracking scheme based on STAR-RIS (Simultaneous Transmission and Reflection RIS) technology, which reduces training overhead while enhancing system communication and sensing capabilities. In [13], beam training in terahertz (THz) communications was investigated, and a dual-layer true time-delay architecture was proposed to mitigate beam squint effects and improve beam tracking accuracy. Furthermore, the authors of [14] explored the application of RIS in Integrated Sensing and Communication (ISAC) systems, proposing a robust joint beamforming scheme to enhance the reliability of secure transmissions. In [15], a secure beamforming method combining RIS and Non-Orthogonal Multiple Access (NOMA) was studied to improve beam tracking and secure communication performance. In addition, the authors of [16] provides a joint mmWave sensing-and-communication framework that demonstrates how an IRS can simultaneously facilitate high-accuracy environmental sensing and data transmission. Furthermore, the authors of [17] proposes an active sensing scheme that significantly improves multiuser beam-tracking accuracy and robustness under dynamic channel conditions. Despite significant theoretical advancements in RIS research, particularly in intelligent beamforming, optimized feedback mechanisms, and low-overhead CSI estimation, most studies remain in the theoretical simulation stage, with limited research on prototype-based RIS experiments [18; 19; 20; 21]. The deployment of practical RIS devices is constrained not only by hardware computing capabilities but also by feedback mechanisms. Therefore, developing more feasible RIS control mechanisms is necessary to meet the requirements of real-world wireless communication environments [22; 23; 24; 25]. Regarding prototype-based experimental research on RIS beam tracking, the authors of [26] studied the independent wave control characteristics of a 1-bit STAR-RIS. The study proposed a six-layer metal structure capable of independently controlling the transmission and reflection wave phases, with each unit achieving a 180\({}^{\circ}\) phase shift through p-i-n diodes. In [27], a 2-bit phase reconfigurable Intelligent Reflecting Surface (IRS) was proposed and experimentally validated in real-world environments.