Wireless communication is the backbone of modern technology. Without this, we can’t fulfil the requirement of this technical world. Today we have so many types of wireless technology but most of them use radio frequencies which is harmful to humans and animal mostly for birds. So at this stage, we need a new technology which removes or reduce this harm to some extent. In this way, new technology is need of today in the wireless communication field and it is true that necessity is the mother of invention so this need introduce a new kind of wireless communication technology that is Li-Fi (Light Fidelity) which uses visible light to transmit data from sender to receiver. This is basically high speed visible light communication technology.
The major difference in Li-Fi and the other wireless technology is zero impact on health, Li-Fi uses light to transmit data whereas others mostly use radio frequencies that make it more harmful. Also, day by day radio frequencies band is occupied at a very fast rate and according to many surveys till 2035 it will entirely be occupied. In that condition, we need an alternative way of wireless communication and Li-Fi is going to capture the whole market there. We know that Li-Fi is based on visible light which has 10,000 times larger band spectrum than the radio frequencies band which opens a great chance to implement it in the real world. Also, LiFi can provide much higher speed than today’s network as it relay on the light. So Li-Fi is the perfect solution and has edge over other communication technologies to handle heavy traffic and security related issues and provide an error-free transmission technology. Thus, Li-Fi technology will bring a revolutionary change in the wireless communication field.
If we talk about the past of communication then we have used several techniques like birds, messengers and many other methods to transfer data or message from one place to another in ancient time which has now replaced by technology where we come across some new way of sending and receiving messages like wired networks further we got wireless technology like Bluetooth, Infrared and other Radio frequencies technologies. Our scientists are putting lots of efforts in research to search for ways to improve communication and their efforts brought the biggest blast in technology in starting of 21st century in the form of Li-Fi.
Let’s talk about how Li-FI came. The term Li-Fi firstly coined by a German Professor Harald Haas at TED Global Talks- ‘Wireless Data from Every Light Bulb’ in July 2011 which is held in Edinburgh. According to him LED bulb can process the signal through its light and it is capable stream a full HD video on a computer wirelessly. According to his research, a 1W bulb is enough to provide connectivity to four normal computers. Li-Fi is a short-range VLC(Visible Light Communication) based communication technology which uses visible light ranges between 400THz(780nm) to 800THz(375nm) as an optical carrier for data transmission same as Wi-Fi where we use radio frequencies carriers. After TED Global Talks conference Professor Haas set up a private company named ‘Pure visible light communication’ (now ‘PureLi-Fi’) to put Li-Fi into the corporate world.
In September 2013 the company launched first Li-Fi product ‘Li-1st’ funded by the UK government with Cisco. The company introduced its second product Li-Flame in December 2014. In starting days Li-Fi was only limited to signal bulb but the University of Oxford and University of Edinburgh multiple arrays of the bulb which was able to transfer data from one bulb to another. Professor Haas introduced Li-Fi internet at his second TED Global Talks- ‘Forgot Wi-Fi meet new Li-Fi Internet’ in November 2015 where he used solar panels to transmit data. PureLi-Fi developed first Li-Fi dongle Li-Fi-X which can simply work on Plug and Play theory and able to provide connectivity to any device just by plugging it in the USB port. Most importantly even IEEE also accepted Li-Fi as a complement of Wi-Fi in July 2017 under-recognized under 802.11 standard. The Li-Fi market is projected to have 82% growth from 2013 to 2018 and be worth over $6 Billion per year by 2018.
Now let’s talk about the working principle behind Li-Fi. It is based on Visible Light Communication which is a subset of the optical wireless communication field. Li-Fi uses photons which emitted from a LED bulb in the form of a stream of light when an electrical current is applied to the LED bulb. These bulbs acts are semiconductor which means it can change its brightness at a good rate. This capacity provides us with a medium to transmit a signal by the modulation of the brightness of an LED bulb at a different rate.
This modulation converted data into a stream of 0’s and 1’s by switching a light bulb. This switching is done at very high speed and hence can’t be recognized by human eyes. So we see it as a continuous light, but a highly sensitive photodiode can detect this modulated signal which senses the change in intensity as data. Thus, we can get high-speed seamless data transfer technology better than other radio frequency technology.
As we already discussed the working principle behind the Li-Fi network and we know that it works on light emitted from an LED bulb. This bulb transmits data in the stream of binary data from a light source to discuss. Li-Fi architecture consists of much more components which include the following:- 1. Server and Cloud 2. Streaming cable 3. LED cable 4. Photo Detector 5. User Device
Here server works as a usual server to store data. From the server, we have streaming cables commonly known as optical fiber cables. These cables used to stream content from the server to the user. This system is the same as the present working system. Now the data signal carried to the user’s home and it will connect to a light source like a LED bulb here LED bulb can be considered as the router in the present network.
The LED bulb will flicker continuously at very high frequency with varying its intensity. This change in intensity will occur by constant current and it will transfer data in the form of 0’s and 1’s, 0 will be off and 1 will be on. This binary data stream will be detected to highly sensitive photodiode which can be installed inside the device of the user. This photodiode provides amplified and processed data to the user. Here the area which covers by light is the service area.
Now we will see some advantages of Li-Fi it provide low disturbance and overcome bandwidth shortage issue, it is more secure, it can be used in underwater communication, we can get internet in aircraft with Li-Fi, it has no bad effect on our health, it is power efficient and most importantly it provides high-speed data rates. Thus it is very good to have technology such as Li-Fi in our future.
At the last we will talk about challenges against the main challenge for Li-Fi is interference with other light mainly sunlight, when sunlight is present it can’t work properly so it can’t come in mainstream data transfer technology until and unless it counters the interference issue because we need to share files or use the internet most of the time outdoor also. The second main problem is portability, it is not suitable for home also because every time we can’t be in a specific area suppose if we go to the toilet then we will be disconnected to the network unless led is present there also. It is a revolutionary technology and it is faster, more secure with huge bandwidth than any other current technology it has some challenges of portability and interference with sunlight because of this it is not suitable for outdoor use currently but if we overcome this then it will surely overtake its competitor i.e. Wi-Fi, In today’s scenario it is more suitable for office and industries where there is specified closed workplace where it can replace the current technologies because of its above-mentioned advantages along with reliability and efficiency in terms of cost and power.
