LiFi is a visible light communication (VLC) technology which makes use of light waves instead of radio waves for wireless data transfer. The term which is short for "Light Fidelity" was coined by Harald Haas who first developed the modern concept of LiFi with his research team at the University of Edinburgh. As a high speed, wireless broadband technology, LiFi was developed to address the challenges and overcome limitations faced by wireless communication technologies operating in the radio spectrum below 10 GHz. With more and more mobile devices being connected every day, radio frequencies are becoming congested. Overloaded network traffic lends existing RF infrastructures to spectrum crunches. With Internet of Things (IoT) opening up a whole new world of opportunities, LiFi is deemed to bring sense to the exciting digital revolution which demands immersive connectivity.
How Does LiFi Work
LiFi transmits data by modulating LED light to create binary code (on = 1, off = 0). A combination of 1s and 0s generates different data strings which are demodulated by a photodetector (photodiode receiver). The photodector produces an electrical current in proportion to the stream of light. The electrical current is then passed onto an analog-digital converter. Demodulated signals are decoded and forwarded to a connected device, such as a computer, tablet, smartphones, television or a smart appliance. To act as a network access point that provide bidirectional communication, the LiFi device must be designed to provide both uplink and downlink connection. Besides the downlink which uses visible light to transmit data from the light source to digital terminals, an uplink connection must be established to complete the full duplex communication. To avoid glare from the photodiode receiver, the uplink channel uses invisible parts of the light spectrum such as infra-red to upload data back to the source. Some LiFi solutions feature a hybrid network structure that combines Li-Fi with the conventional radio frequency (RF) communication.
