Due to the wide use of mobile multi-media devices, Wireless Fidelity (Wi-Fi) is getting more and more popular in public. Since 2013, more than 5 billion smart devices use Wi-Fi every day, and this causes a systems overload  This often happens often to people at airports and in crowded cafes. When a huge amount of people arewithin the same access point (AP), the transmission resource allocated to each individual is very small and the user service would be seriously affected. How can we solve this problem?

Light Fidelity (Li-Fi), which employs the visible light spectrum to convey digital signals, is seen as a potential technique in next generation wireless communication. In general, LED lamps are the best options for Li-Fi AP, and the signals are transmitted by modulating the illumination power. Due to the innate property of light, a Li-Fi transmitter can only serve a confined area, which makes it possible for a dense deployment of Li-Fi APs and massive reuse of the bandwidth. As a result, people previously in the Wi-Fi system can now be divided into several groups when using Li-Fi, and each user would achieve a higher data rate by using more of the transmission resource.

However, the light beams used by Li-Fi are susceptible to blockages, and the devices would be disconnected to the Internet when they cannot receive any light from the Li-Fi AP. What can we do? Recently research has been undergoing on Li-Fi/Wi-Fi hybrid network. The twins, Li-Fi and Wi-Fi, can be combined to offer a more efficient and robust wireless service. Li-Fi provides a high data rate and Wi-Fi guarantees an ubiquitous coverage. Thus, users can choose Li-Fi generally for high data rates, and automatically switch to Wi-Fi while the light is blocked or they move outside the Li-Fi coverage area. Since some of the network load is served by Li-Fi, people served by Wi-Fi can achieve better user experience by using more transmission resource. Li-Fi, which acts as a complement to Wi-Fi, can significantly improve the quality of the network. In the future, it can be imagined that the Li-Fi/Wi-Fi hybrid network can cover the whole world and really gives us a life without hidden corners of Internet.


Yunlu Wang

Li-Fi PhD Research Student