The invention of the blue-light light-emitting diode (LED) has substantially impacted the world’s energy consumption since its invention in 1993. In a relatively short time, the use of LED lighting across the globe has skyrocketed, vastly decreasing the amount of electricity explicitly used for lighting purposes. LEDs are expected to dominate the lighting market throughout the next decade, lowering the world’s energy consumption by offering efficient lighting solutions. Most humans spend more than half of their waking hours indoors and thus require reliable, efficient lighting options. Beyond the simplicity of illumination, a lighting network has the potential to impact the human experience in a plethora of ways. Human-centric lighting considers the overall needs of people in indoor environments. It can offer network-based solutions that focus on improving the lives of humans, from comfort and productivity to overall well-being and therapeutic treatments. 

What is Visible Light Communication?

The rapid development of 5G networks has revealed opportunities to further develop technologies in the field of visible light communication (VLC) over LEDs. LEDs can support high-speed adjustment of light intensity for data transmission, highlighting the range of their utility in emerging technologies. Since LEDs are considered the optical transmitters for VLC, LED-based networks can be used for optical wireless telecommunication applications beyond their basic illumination functionality. Because of its versatility, VLC can be used for various scenarios, from light positioning in smart buildings to light intensity modulation that impacts human health.  

The feasibility of VLC opens the door to countless potential uses that support information services. VLC transmits information by adjusting LED light intensity. Uses from data transmission to optical therapy are possible with this emerging technology. Researchers from the information and communication technology fields (ICT) are discovering ways for LED lights to facilitate the integration of illumination networks with additional intelligent control systems. The key functionalities of an IoL platform pull technologies from various fields together to support the well-being and productivity of humans and decrease energy consumption. 

What is IoL?

In a study recently published in Intelligent and Converged Networks, a team of researchers proposed the idea of Internet of Lighting (IoL), which interfaces with the Internet of Things (IoT) to offer a fully interconnected illumination network. In the IoL system, each LED light contains sensors for occupancy and movement, hazardous gasses, and other information services. The sensing nodes provide actionable information to initiate a response if needed.  

The concept of the IoL utilizes sensors and communication modules within LED luminaires to create a node. It then uses telecommunication technology such as 5G wireless communication or PLC to complete the network and transmit information. The nodes can gather data such as hazardous gas levels, motion, light intensity, etc. Multiple nodes establish a sensor network that sends collected data to an operating center to analyze the data and respond effectively. 

An example scenario in the study outlines the network’s response to a gas leak in a nursing home. The node-based sensors detect the leak, causing an alarm to notify residents, facility managers, and the hazard prevention team while automatically starting the ventilation system. The lights can also illuminate an evacuation path to safety for those in the building. 

The numerous applications of IoL focus on the benefits of wireless communication and the advantages of establishing a genuinely human-centric lighting system. Human-centric lighting, or lighting that improves human health and well-being, requires flexible dimming schemes and customizable qualities. 

The study describes three layers of IoL: the sensing layer, the network layer, and the intelligent lighting control layer. The sensing layer provides comprehensive sensing of various informational inputs. The network layer provides reliable access with a heterogeneous structure of coordination and control mechanisms. The intelligent lighting control layer provides potential functionality for optical intervention therapy. 

Movement recognition information is captured through a real-time beam alignment VLC system. The system adapts the emission angle of the light according to the tracking data and can change the direction of the light beam. Image processing algorithms at the transmitter calculate the adjustment angle for the beam. VLC network integration must support the requirements of advanced applications such as video transmission and real-time positioning. Therefore, the base station or network gateway of IoL needs the appropriate scheduling algorithms to ensure the efficiency of the network across diverse scenarios. Data freshness is a critical aspect to consider, especially for real-time responses to user needs. Emerging metrics such as Age of Information (AoI) and Age of Synchronization (AoS) can soon prove vital for system optimization. 

Researchers focused on various experiments to test the IoT functionalities in the study. For example, they experimented with a VLC design that includes real-time beam positioning, which directs light according to the location of humans in the room. Researchers must also experiment with algorithms for illumination timing and utilizing timing requirements to increase the network’s efficiency, decreasing energy waste. ICT technology can monitor environmental changes and seamlessly respond to those changes. IoL can offer complete control of all lighting functionalities and aims to understand users’ preferences fully and needs to create an ideal lighting environment automatically. 

Can Lighting Improve Human Health and Well-Being?

Gathering useful information is vital to providing fully functional, energy-efficient lighting. In addition, LED-based lighting technology can substantially improve human health and well-being by utilizing information about environments and users. The amalgamation of technologies within the IoL platform offers a smart solution for many businesses or organizations. Real-time communication and system interconnectedness would create a human-centric lighting solution.  

IoL systems can emulate the changes in natural lighting to help regulate circadian rhythm. By creating a specific lighting environment that incites attentiveness, prevents melatonin secretion, promotes workplace productivity, or fosters relaxation and sleep, an intelligent IoL system can potentially impact users’ psychological well-being and productivity. Non-intrusive light therapy treatments based on ICT in an IoL system can substantially change the landscape of light therapy and light stimulation treatments.    

The use of IoL to support human health extends from previous studies regarding optical therapy. Light is used to treat neurodegenerative diseases and skin ailments; IoL opens the door to effective, non-intrusive potential treatments. The experiment in this study that used IoL for optical treatments focused on stroboscopic flashes. The environment used in the experiment imitated an office environment with the LED light mounted on the ceiling. Volunteers sat quietly under the LED light, and the flicker frequency was controlled using the IoL platform. Although only flicker frequency was tested in this experiment, other variables such as color temperature, flicker waveform, and light intensity will be tested in future experiments. The photoplethysmograph, thermometer, and ECG and EDA tests gathered and reported the physiological data of the volunteers. The researchers confirmed that an IoL platform has the potential to influence human emotion and brain activity using the automatically controlled flicker frequency of the LED light. 

It is undeniable that light affects human health, whether to reconnect with one’s natural circadian rhythm, increase workplace productivity, or manage health issues. Our reliance on light, mainly indoor lighting, illuminates an abundance of factors that need to be considered when exploring the concept of human-centric lighting. The integration of lighting and environment can be utilized to maximize health benefits and energy savings. The concept of IoL introduces us to a dynamic system with certain advantages from functionalities such as real-time perception, seamless response, and smooth interconnection with a smart system supported by the IoT. The continuous monitoring and analysis of and response to human behavior to fully adapt an indoor lighting system to meet the full range of needs for all users are on the brink of reality. New emerging technology requires an interdisciplinary approach to bring intelligent lighting into the future.

nLUMINAIRE and Human-Centric Functionalities

Many of these human-centric features are available now using PoE connected lighting systems. The key to adapting lighting to the needs of users lies in the multifunctional sensor. Similar to the LED-based sensor being explored in the IoL concept, the nLUMINAIRE sensor can also collect and transmit occupancy, motion, and static presence data that can be used to customize lighting schedules. Also using IoT functionality, the nSensor utilizes machine learning algorithms to process real-time data. With multidimensional coverage, the nSensor can facilitate human-centric lighting in diverse environments. The capabilities of the nManager elevate the human-centric aspect of PoE connected lighting systems even further. Extending the utility of sensors and dimmers, the nManager provides a personalized user interface allowing users to manage the lighting system remotely. This unified software platform pulls together the components of the nLUMINAIRE suite to offer a lighting solution that improves operational efficiency, saves money and energy, and tailors to the user’s unique needs. The connectedness of systems over the IoT platform will push the boundaries of what is possible; the future of lighting is most certainly bright.