## 1 Introduction  
The Fourth Industrial Revolution, also known as Industry 4.0, focuses on optimizing resources while integrating advanced human skills. It is characterized by the increasing use of robotics, artificial intelligence (AI), the Internet of Things (IoT), and big data, which, together, are transforming industries, services, and daily life [1]. A key aspect of this revolution is the replacement of human labor with machines or the enhanced interaction between the two [2]. Similar to past industrial revolutions, Industry 4.0 seeks to improve efficiency in resource utilization. Automation is a prime example, enabling, e.g., the development of autonomous vehicles and accelerating the adoption of car-sharing by removing the need for human drivers. A major technological enabler of Industry 4.0 is the evolution of mobile communications, particularly the transition from fifth-generation (5G) to sixth-generation (6G) systems. While 5G enabled direct machine-to-machine communication [3], 6G aims to advance these capabilities with real-time data exchange, ultra-reliable low-latency communication, and high-speed connectivity for industrial automation and IoT applications. These developments are critical for applications like autonomous systems, remote healthcare, and smart infrastructure. The upcoming 6G will further extend these capabilities by enabling advanced services such as holographic communication, immersive extended reality (XR), and next-generation autonomous systems. Additionally, 6G will facilitate seamless interaction with high-speed unmanned aerial vehicles, further expanding its impact across multiple sectors. To support these applications, 6G must achieve ultra-high data rates, an increased spectral efficiency, and minimal latency. Among the key enabling technologies, Large Intelligent Surfaces (LISs) stand out as a promising approach to improving spectral efficiency and communication reliability through large-scale antenna arrays. To meet the demands of these new applications, 6G will need to achieve speeds of up to 1 terabit per second, substantially increase network capacity to support a higher density of connected devices, and dramatically reduce latency. These improvements are essential for real-time applications such as autonomous driving, online gaming, and the remote control of critical infrastructure. To enable such high-performance connectivity, 6G will rely on cutting-edge technologies, including block transmission techniques, advanced error correction codes, and LISs. The LIS concept represents an evolution beyond massive multiple-input multiple-output (MIMO) systems, incorporating an even larger number of antenna elements to enhance spectral efficiency and data transmission rates. By integrating these innovations, 6G will provide the necessary foundation to interconnect billions of IoT devices with an unprecedented speed, reliability, and efficiency, driving the next phase of industrial and technological advancement. The concept of LISs has gained significant attention as a means of improving wireless communication efficiency through large-scale antenna arrays. Unlike conventional MIMO systems, LISs exploit a dense array of antennas spread over an extended area, enabling enhanced beamforming and spatial multiplexing. Wireless communications are typically established beyond the Fraunhofer distance, meaning that they operate in the far field [4]. While individual antenna elements of an LIS function in the far field, the LIS, as a whole, operates in the near field [4; 5; 6; 7]. As a result, it can be considered a near-field beamformer, distinct from conventional beamformers in that it not only directs beams along azimuth and elevation angles, but also adjusts them based on distance. This latter capability (directing the beam through distance) helps to mitigate interference between users who share the same bearing and elevation but are positioned at different distances.