### OCC as an Enabler for 6G  
As the deployment of 5G progresses, it becomes paramount to establish the groundwork for the subsequent generation, 6G. This forthcoming phase will enable cutting-edge technologies. For instance, consider realistic holographic communication, which enhances the natural perception of 3D holograms, or Extended Reality (ER), amalgamating augmented, virtual, and mixed reality to offer high-quality immersive experiences. The Tactile Internet, characterized by low latency, enabling real-time applications ranging from remote surgery to industrial control, is also noteworthy. In addition, multisensory experiences encompassing all human senses, including taste and smell, open up new possibilities across various industries. Furthermore, detailed digital twins of physical objects advance automation and intelligence in manufacturing. Similar to its role in 5G, the Internet of Things (IoT) remains significant, enabling broader and faster data acquisition. Additionally, intelligent transport and logistics ensure secure and efficient mobility [9]. These innovations signify an important shift in how technology is interacted with and hold the promise of revolutionizing industries such as healthcare, terrestrial and aerial vehicular networks, satellite communications, entertainment, logistics, and industrial settings.  
To facilitate the proliferation of these new technologies and advancements, it is essential to ensure a series of changes in communication technologies. These requirements primarily encompass aspects related to latency, data rates, connection density, mobility, costs, energy efficiency, and security [9]. It is especially in the latter five aspects that OCC plays a pivotal role. Unlike Radio Frequency (RF) waves, which can be detected from several meters away, OCC confines the possibility of detection to the area illuminated by the light source, providing greater confidentiality, particularly indoors. Similarly, OCC technology allows for cost reduction in terms of acquisition, mobility, and maintenance due to its straightforward operation and installation. Moreover, it avoids contributing to electromagnetic spectrum saturation and is more immune to transmitter interference issues. The use of cameras also significantly increases the number of transmitters in scenarios, effectively monitors their potential mobility, and achieves location precision of less than a centimeter [8]. The key requirements proposed for 6G, as well as the contribution of OCC technology to these objectives, are detailed in Table 1.  
\begin{table}
\begin{tabular}{l l l} \hline
**6G Requirement** & **Target Value** & **OCC Support** \\ \hline Peak Data Rate & Up to 1 Tbps & No \\ User-Experienced Data Rate & 1 Gbps or higher & No \\ User Plane Latency & 100 \(\upmu\)s or lower & No \\ Mobility & Up to 1000 km/h & No \\ Connection Density & Up to 10\({}^{7}\) devices/km\({}^{2}\) & Yes \\ Energy Efficiency & 10–100 times better than 5G & Yes \\ Peak Spectral Efficiency & Three times higher than 5G & Yes \\ Area Traffic Capacity & Up to 1 Gbps/m\({}^{2}\) & Yes \\ Success probability (Reliability) & 1–10\({}^{-7}\) & Yes \\ Signal Bandwidth & Up to 1 GHz or higher & No \\ Positioning Accuracy & Centimeter-level precision & Yes \\ Coverage & 3D (terrestrial–satellite–aerial) & Yes \\ Timeliness & Real-time data emphasis & No \\ Security and Privacy & Ensured confidentiality, integrity, & Yes \\  & authentication & \\ Capital and Operational Expenditure & Cost-effective networks & Yes \\ \hline \end{tabular}
\end{table}
Table 1: The 6G requirements and OCC support.  
The primary applications of OCC in the context of 6G will be oriented toward intelligent transportation systems [17], indoor positioning systems [8], and sensor networks [4] due to the aforementioned aspects. They will also be instrumental in achieving ubiquitous connectivity thanks to their excellent performance in underwater environments [18]. In this realm, OCC will also enhance node mobility compared to widely used wired systems.