LiFi (Light Fidelity)

Li-Fi stands for Light Fidelity. The technology is very new and was proposed by the German physicist Harald Haas in 2011 TED (Technology, Entertainment, Design) Global Talk on Visible Light Communication (VLC). Li-Fi is a wireless optical networking technology that uses light emitting diodes (LEDs) for transmission of data. The term Li-Fi refers to visible light communication (VLC) technology that uses light as medium to deliver high-speed communication in a manner similar to Wi-Fi and complies with the IEEE standard IEEE 802.15.7. The IEEE 802.15.7 is a high-speed, bidirectional and fully networked wireless communication technology based standard similar to Wi-Fi’s IEEE 802.11.

Wi-Fi is of major use for general wireless coverage within building, whereas Li-Fi is ideal for high density wireless data coverage in confined area and especially useful for applications in areas where radio interference issues are of concern, so the two technologies can be considered complimentary.

Li-Fi provides better bandwidth, efficiency, connectivity and security than Wi-Fi and has already achieved high speeds larger than 1 Gbps under the laboratory conditions. By leveraging the low-cost nature of LEDs and lighting units, there are lots of opportunities to exploit this medium. Li-Fi is the transfer of data through light by taking fibre out of fibre optics and sending data through LED light bulb.

Comparison Between Li-Fi and, Wi-Fi and other Radio Communication technologies

Table 1: Comparison of speed of various wireless technologies

Technology Speed

Li-Fi ~1 Gbps

Wi-Fi – IEEE 802.11n ~150 Mbps

IrDA ~4 Mbps

Bluetooth ~3 Mbps

NFC ~424 Kbps

Table 2: Comparison of Wi-Fi and Li-Fi

Parameter Li-Fi Wi-Fi

Spectrum Used Visible Light Radio Frequency

Standard IEEE 802.15.7 IEEE 802.11

Range Based on Light Intensity Based on Radio (< 10m) propagation & interference

( < 300 m)

Data Transfer Rate* Very high ( ~1 Gbps) Low (100 Mbps-1 Gbps)

Power consumption Low High

Cost Low High

Bandwidth Unlimited Limited

Advantages of Li-Fi

a) Efficiency: Energy consumption can be minimised with the use of LED illumination which are already available in the home, offices and Mall etc. for lighting purpose. Hence the transmission of data requiring negligible additional power, which makes it very efficient in terms of costs as well as energy.

b) High speed: Combination of low interference, high bandwidths and high-intensity output, help Li-Fi provide high data rates i.e. 1 Gbps or even beyond.

c) Availability: Availability is not an issue as light sources are present everywhere. Wherever there is a light source, there can be Internet. Light bulbs are present everywhere

– in homes, offices, shops, malls and even planes, which can be used as a medium for the data transmission.

d) Cheaper: Li-Fi not only requires fewer components for its working, but also uses only a negligible additional power for the data transmission.

e) Security: One main advantage of Li-Fi is security. Since light cannot pass through opaque structures, Li-Fi internet is available only to the users within a confined area and cannot be intercepted and misused, outside the area under operation.

f) Li-Fi technology has a great scope in future. The extensive growth in the use of LEDs for illumination indeed provides the opportunity to integrate the technology into a plethora of environments and applications.