A Comparative Survey of Optical Wireless Technologies: Architectures and Applications (1810.02594v1)

Abstract: New high-data-rate multimedia services and applications are evolving continuously and exponentially increasing the demand for wireless capacity of fifth-generation (5G) and beyond. The existing radio frequency (RF) communication spectrum is insufficient to meet the demands of future high-datarate 5G services. Optical wireless communication (OWC), which uses an ultra-wide range of unregulated spectrum, has emerged as a promising solution to overcome the RF spectrum crisis. It has attracted growing research interest worldwide in the last decade for indoor and outdoor applications. OWC offloads huge data traffic applications from RF networks. A 100 Gb/s data rate has already been demonstrated through OWC. It offers services indoors as well as outdoors, and communication distances range from several nm to more than 10000 km. This paper provides a technology overview and a review on optical wireless technologies, such as visible light communication, light fidelity, optical camera communication, free space optical communication, and light detection and ranging. We survey the key technologies for understanding OWC and present state-of-the-art criteria in aspects, such as classification, spectrum use, architecture, and applications. The key contribution of this paper is to clarify the differences among different promising optical wireless technologies and between these technologies and their corresponding similar existing RF technologies

• The paper presents a comprehensive assessment of various optical wireless technologies to address RF spectrum limitations and meet rising high-data-rate demands.
• It evaluates key systems such as VLC, LiFi, OCC, FSOC, and LiDAR, detailing their unique architectures, benefits, and challenges in diverse applications.
• The study emphasizes integrating OWC with RF networks and outlines future research to overcome issues like atmospheric attenuation and limited data rates.

Overview of Optical Wireless Technologies

The paper conducts a comprehensive survey on Optical Wireless Communication (OWC) technologies, focusing on their architectures and applications. As the demand for high-data-rate multimedia services continues to escalate, particularly in the context of fifth-generation (5G) communication and beyond, OWC has emerged as a promising solution to the limitations of the existing Radio Frequency (RF) communication spectrum. This paper meticulously examines various OWC technologies, such as Visible Light Communication (VLC), Light Fidelity (LiFi), Optical Camera Communication (OCC), Free Space Optical Communication (FSOC), and Light Detection and Ranging (LiDAR).

The OWC technologies leverage a broad spectrum including visible light (VL), infrared (IR), and ultraviolet (UV), offering an unregulated and wide-ranging spectrum to mitigate RF spectrum constraints. Each of these technologies utilizes unique principles and offers distinct advantages and limitations, making them suitable for diverse applications ranging from chip-to-chip communication to inter-satellite links.

Key Technologies

1. Visible Light Communication (VLC): VLC utilizes LED or LD light sources for communication, simultaneously supporting illumination and data transmission. Despite the constrained usage in outdoor scenarios due to natural light interference, it facilitates high-data-rate indoor communication and offers promising applications in smart lighting, localization, and connectivity.
2. Light Fidelity (LiFi): Expanding upon VLC, LiFi employs bidirectional communication, potentially using IR or UV for uplinks. It serves as a replacement or supplement for Wireless Fidelity (WiFi), offering higher data rates and improved security features. LiFi's deployment in attocells can significantly offload RF network traffic, crucial for dense urban environments.
3. Optical Camera Communication (OCC): OCC systems, employing LED transmitters with camera receivers, excel in providing reliable communication under variable ranges and in the presence of significant interference from other light sources. While the data rate remains a limitation, OCC offers robust non-interference communication suitable for vehicular and indoor positioning applications.
4. Free Space Optical Communication (FSOC): FSOC is capable of ultra-long-range communication using a focused laser beam, operating across IR, VL, and UV spectra. It offers a feasible solution for high-capacity backbone networks, although atmospheric conditions can affect reliability.
5. Light Detection and Ranging (LiDAR): LiDAR is primarily utilized for high-resolution 3D mapping and remote sensing. This technology is integral in applications such as autonomous vehicles and environmental monitoring, providing precise position and imaging data by analyzing scattered light.

Implications and Future Directions

The research highlights the potential of OWC technologies to complement existing RF systems and alleviate spectrum shortages, especially as the number of interconnected devices burgeons with IoT expansions. The paper suggests hybrid network structures integrating OWC and RF elements to enhance network flexibility and resilience under diverse environmental and operational conditions.

Further research is warranted to address some persistent challenges within OWC systems, such as atmospheric attenuation in FSOC and limited data rates in OCC. Additionally, there is a need to develop seamless handover protocols to enable uninterrupted mobility across diverse communication platforms, including OWC. Exploration into extending the optical spectrum beyond traditional wavelengths could unlock additional capacities and efficiencies.

In summary, OWC technologies present a compelling case for consideration in future wireless communication infrastructures. Their ability to provide high data throughput, interference-free operation, and additional security features positions them as key enablers for the impending demands on global communication networks. As these technologies mature, they promise to redefine connectivity dynamics and assist in meeting the exponential growth in wireless communication needs.