Li-Fi: Tomorrow’s connectivity with the power of light

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Philips Lighting’s Li-Fi device

The visible light spectrum remains an untapped resource with a large bandwidth,
making Li-Fi the connectivity technology of tomorrow.

By Paromik Chakraborty

As more and more devices get connected to the Internet, soon there will a need for bigger bandwidth to accommodate the massive volume of data transactions. Light Fidelity (Li-Fi) can be a stepping stone towards a new era of communication that utilises visible light. Although in developmental stages, Li-Fi offers a great scope of applications in big business areas like banks, large enterprises, aviation and even defence.

How Li-Fi works
The underlying technology of Li-Fi involves a sophisticated technical upgrade of luminaires that enable seamless transfer of data through the visible light spectrum. The luminaire consists of a normal RJ-45 Ethernet port (also present in Wi-Fi routers), through which the Ethernet cable is connected.

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Inside the luminaire there is a small modem and some specific components that allow the data being brought through the Ethernet cable to be coded into light packets. Emitted light is modulated at a high frequency (not detectable by human eye) to carry data. A small device containing sensors and microprocessors is required, which reads and decodes the light packet and displays the data on the screen.

Scope and benefits of Li-Fi
Currently, various pilots and proofs-of-concept of Li-Fi projects have been deployed, mainly in large enterprises and certain government sectors.

Data travelling through light cannot be hacked. It can be accessed only by those who are available within the coverage range of the luminaire. Usually, a luminaire has a 3-metre coverage radius, ensuring only a handful of personnel can access the data contained in the light. This improves the control on access to the network. Since Wi-Fi usually works in the radio frequency (RF) bandwidth (2.4GHz and 5.0GHz), the risk of signal interference becomes nil using Li-Fi (430THz-770THz).

Sumit Joshi, vice chairman and managing director, Philips Lighting India, says, “Li-Fi is significantly better than Wi-Fi in applications where RFs may interfere with the equipment, such as in hospitals, or places where Wi-Fi signals cannot reach or are weak, such as underground locations, or secure bank rooms handling sensitive data. Additionally, it can provide secure, personal connectivity for senior management or anyone else concerned about data privacy.” Defence and aviation industries are also leveraging Li-Fi.

There are more benefits. Deepak Solanki, founder and chief executive officer, Velmenni R&D Lab, says, “The visible light spectrum is unlicensed and, hence, is free to use for Li-Fi services. Moreover, Li-Fi enables an evenly distributed network. In certain router-based Wi-Fi setups in enterprises, when antennae are facing towards a specific direction, receivers in that direction get better signal strength compared to others. On the other hand, Li-Fi signals remain consistent throughout a workspace, since luminaires are usually installed in regular intervals.”

Real-world applications
Li-Fi is currently under various stages of R&D and is steadily picking up commercial recognition. Philips Lighting, the first major lighting company to offer Li-Fi-enabled luminaires, has partnered with various government and private bodies to deploy Li-Fi commercially at pilot levels in India. In fact, a substantial portion of its office network utilises Li-Fi.

Philips’ Li-Fi-enabled LED office lighting for commercial environments mainly come in the form of downlights or 2×2 luminaire with speeds of 30Mbps—sufficient to stream high-quality media files or transfer large volumes of files.

Education and Research Network (ERNET), government of India, has set up a Li-Fi test bed to test the capabilities of Li-Fi in various indoor and outdoor applications. Initially funded internally by ERNET, the government has partnered with IIT-Madras and Philips Lighting to carry out the two-year (2017-2019) planned R&D project.

Dr Neena Pahuja, director general, ERNET, says, “As this technology can provide high speed connectivity, it can be extensively used for applications such as video-on-demand, virtual reality (VR) applications and robotic surgeries in the future. Also, in places where Wi-Fi gets impacted because of interference—for example, the radiology areas in hospitals as well as underwater—Li-Fi can be used for data transmission.”

Current limitations
Solanki mentions that lack of proper standards is a major reason why Li-Fi has not yet picked up full pace. He says, “Existing standards like IEEE 802.15.7 (for visible light communication) are outdated and do not define many aspects of Li-Fi. For large-scale adoption, standardisation is essential. Once the standards are in place, Li-Fi integration will become popular in lighting as well as smart devices like smartphones.”

Experts from the connectivity domain and R&D bodies like ERNET are working together to create standards for Li-Fi.

Li-Fi does not have any specific cost points as of now and is more requirement-oriented. Initial investments are higher than a regular Wi-Fi network setup. However, as Li-Fi becomes more popular, prices will reduce. Overall, the technology, at the moment, is mostly restricted to large businesses and government departments.

The way forward
Li-Fi speeds will increase and the technology will become more stable going forward. For instance, Philips Lighting’s Li-Fi solution will improve, to deliver speeds of 60Mbps by early 2019, and Li-Fi support will be available in tubular lighting form factors as well. Some Li-Fi research efforts have been able to touch speeds up to 10Gbps, indicating great potential for the technology.

With the right design and miniaturisation in place, in a matter of a few years, Li-Fi will penetrate the small- and mid-size business and consumer segments. Solanki says that this will be put into motion once the standards are in place. “Usually, this takes at least two years,” he adds.

Dr Pahuja adds, “We will see a large number of use cases in smart cities. For instance, a smart pole that can be remotely controlled for further saving of energy, get traffic information via connected cameras and act as a hotspot, as required.”
Joshi concludes, “The visible light spectrum remains an untapped resource with a large bandwidth, making Li-Fi the connectivity technology of tomorrow.”

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