Design of a Li-Fi Transceiver

Good morning people,

Nowadays, Wi-Fi is widely used by people. Because this technology is compact, easy to use, secure, and people. At least people think that is true. But, do you know that now there is a new technology for data communication using light? Believe me, it is true :D

Instead of electromagnetic wave, this technology uses light as a media. It sounds complicated, right?

Don’t worry, some students in the India made the simple version of it.

This is all this…

Enjooooyyy….

Download journal here

Author           : Pavas Goswami, Manoj Kumar Shukla

Title               : Design of a Li-Fi Transceiver

Source          : Wireless Engineering and Technology, 2017, 8, 71-86

Summary of Reported Research :

·   Nowadays, Light Fidelity / LiFi begins to be used by people.  There are currently two trends being seen: First, the extension or enrichment of wireless services and other being increased in user demand for these services, but the available RF spectrum for usage is very limited. So, people is replacing RF spectrum with visible light. Li-Fi is the most recent development which is resourceful. In this technology, LEDs are used to transmit data in the visible light spectrum. This technology can be compared with that of Wi-Fi and offers advantages like increased accessible spectrum, efficiency, security, low latency and much higher speed. The software coding is done by using Java (version 8). Successful transmission and reception of text, image and video signals is carried out on the transceiver.

·  The LiFi technology in this design is not a full LiFI, it is named Visible Light Communication / VLC, which is only be used in point to point communication.

·      Visible light communication (VLC) is the term given to an optical wireless communication system that conveys information by modulating light that is visible to the human eye. Communication is achieved by switching LED lights on and off at a speed higher than what is perceptible to the human eye. The receiver of VLC is photodiode.

·    The visible spectrum is the portion of the electromagnetic spectrum having wavelengths from about 380 nm to 780 nm and in terms of frequency. This corresponds to a band of 385 - 789 THz.

·   The key components are an Arduino Uno board, wavelength specific LED and photodiode. Besides the component responsible of generating and capturing the light signals, additional hardware is needed to filter and interpret these signals. For example, a suitable band pass filter can be used to filter out incoming signals with frequencies other than those desired; an optical filter can be a good way to filter out light of other wavelengths; a lens to focus incoming light can be suitable if the light intensity is low. In the case of digital data transmissions, a digital signal processor at both ends of the system is required to process incoming and outgoing data.

·  On-off keying (OOK) is the simplest method to represent data. The logic value zero corresponds to LOW and the logic value one to HIGH. In the VLC case, this means the LED is turned off to transmit a zero and turned on to transmit a one.

·    The software implementation of the project consists of the following separate parts: data packaging, hardware control, transmission synchronization, transmission, encoding and decoding, error handling.

Strength of Reported Invention :

·      Overall, the system is cheap and easy to built.

·      The design process is fast because using Software (Proteus, Eagle CAD, and Java).

·      The prototype can work in dense environment, and less interference.

·      The frequency of the operation is 10.000 times the frequency of RF spectrum.

Weakness of Reported Invention :

·      The Li-Fi prototype designed does not support multi user access.

·      The speed achieved with this prototype is 115,200 bps only.

·      This prototype is not bidirectional.