Max Riegel, “Standardization Status (LC, 5G & Beyond 5G)”, PHOTOPTICS 2022, OWC workshop
Abstract: Standards are an important prerequisite for mass deployment of communication technologies. As Light Communications span a wide variety of applications, a single standard is not able to serve all potential applications enabling high-performance cost-optimized solutions. A first light communications standard specifying short-range visible light communications (VLC) was initiated in 2008 and ratified in 2011 through IEEE Std 802.15.7-2011. The standard provides three different PHY modes with a common MAC to deliver data rates sufficient to support audio and video multimedia services. It considers mobility of the VLC link, impairments due to noise and interference from sources like ambient light. The specification was later revised to IEEE Std 802.15.7-2018 broadening its applicability to wave lengths in the range 190 nm to 10 000 nm, and adding further 3 PHY modes to fully incorporate Optical Camera Communication (OCC) solutions. Currently, an amendment to 802.15.7 is in development further evolving the specification regarding OCC to address more use cases in particular in the domain of Vehicle-to-everything (V2X) communications, and for various deployments in industrial automation. Parallel to the past and ongoing enhancements to 802.15.7, IEEE initiated P802.15.13 to address high speed light communication needs with up to 10 Gb/s over distances of up to 200m unrestricted line. It leverages latest technologies like distributed MU-MIMO and offers three different PHY modes for data rates of up to 2.2 Gb/s per stream. Ratification is expected for 2022. The IEEE 802.11 working group, the home of Wi-Fi, initiated also efforts to complement Wi-Fi with a LC interface. The project P802.11bb is aimed for the high volume mass market to facilitate the extension of common Wi-Fi deployments with LiFi, when radio communication is not possible or is impacted through exhaustion of the radio spectrum. It vastly leverages the IEEE 802.11ax capabilities and minimizes additional functions to the essential pieces to enable very cost-effective chip implementations for the transmission of the base band signal over light instead of a high frequency radio channel. Completion of the amendment is expected for end of 2022. Aside of IEEE, other global standardization organizations are active in light communications as well. The ITU-T Study Group 15 Question 18 started in 2015 an effort to create a light communication variant of its home networking standard G.hn. G.9991, as the LC standard is denoted, adopts basic architecture, the principal design of the OFDM-based PHY, the DL functions, and the management interface from the G.hn base specifications G.9960 to G.9964. The G.9991 specification, initially released in 2019, incorporates a second PHY mode based on Asymmetrically Clipped Optical OFDM that better adapts to the nature of light. Later amendments released in 2020 and 2021 added port based access control according to IEEE 802.1X, and enhanced mobility support to address the needs of mobile terminals in larger deployments. Current light communication standards already fulfill many of the requirements covered in the 5th generation mobile communication system (5G) and can be leveraged to provide 5G services over light communication. However, further standards developments can be expected to better leverage the capabilities of light communications addressing use cases and requirements that are currently outside of the possibilities of wireless interfaces.