Shortcomings of Wireless Fidelity(WiFi) over Light Fidelity(LiFi)
Wireless Fidelity(Wi-Fi) has revolutionized our current way of digital communication. There are about 1.4 million cellular database stations and around 5 billion mobile phones which transmit over 600 terra bytes of data every month. It makes 60% of global internet traffic. This accidental invention of Wi-Fi by an Australian radio astronomer Dr John O’Sullivan has proven to be a blessing in disguise. No matter how much this technology has been a boon to us, there are always two sides to a coin.
Shortcomings of Wi-Fi
- Capacity– Wireless data is transferred using radio waves. Radio waves are limited and expensive. They are scarce hence we only have a certain range of it. Due to this limitation, the amount of data that could be transferred is limited.
- Efficiency– The cellular databases consume a lot of energy. Most of the energy consumed is not used to transmit the radio waves but to cool these database stations down. So the efficiency is about 5%.
- Availability– Although a very rare amount of flights offer Wi-Fi, a huge chunk of airlines don’t. Availability of Wi-Fi at certain hospitals and at places of utmost importance is still questionable.
- Security– These radio waves can penetrate through walls, which allow the interference of data by unauthorized people.
On the other hand, we have 14 billion light bulbs, and visible light is also a part of the electromagnetic spectrum. Now imagine if we could use the spectrum of visible light for communication, with a frequency 10000 times greater than that of the radio waves. Well, this technology exists and it uses light to transfer data. This is called Light Fidelity or Li-Fi.
Li-Fi technology was invented by Harald Haas in 2011 wherein he demonstrated it for the first time in a Ted Talk. It can transfer data at a speed of 224 gigabits per second. It requires light to be switched on all the time. Though, it can be dimmed to a level where it appears to be potentially off.
Li-Fi technology has 10000 times more spectrum and LEDs. The infrastructure is already installed for them to function. The data transmission is through illumination so the light is highly efficient. Light is readily available than Wi-Fi. Hence Li-Fi will reach out to more number of users. Light doesn’t penetrate through walls thereby limiting its access to a particular region and increasing its safety.
Working of Li-Fi
Both Li-Fi and Wi-Fi transmits data using electromagnetic radiation. However, Li-Fi uses visible light and Wi-Fi uses radio waves to transmit data. Li-Fi uses a photo-detector to light signals and signal processing element to convert data into stream-able content. An LED is a semiconductor light source to which constant current electricity is supplied and that can be modulated at very high speeds without being visible to the human eye.
Data is fed into an LED with signal processing technology which sends data that is embedded in its beam at very high speeds to the photo-detector. The tiny changes of the rapid dimming LED bulbs are then converted by the receiver into an electrical signal. The signal is then converted back into a binary data stream that we would recognise as web, video and audio application that run on internet enabled devices.
Li-Fi in V2X
V2X (Vehicle to Everything) communication’s main aim is to provide road safety. Studies show that 60% of road accidents can be avoided if the driver could have been informed about the upcoming danger 0.5 seconds earlier. We use Li-Fi because it is more efficient and quick. By integrating the two technologies, we get fast communication between the vehicles which can potentially save a lot of lives.
Possible working Scenario in V2X.
Streetlights are the crux of the system. They send and receive information from the on-road vehicles. Data distribution is done by Power Line Communication and the modulation of the data is done by the LEDs. The information sent out is modulated light pulses from street lights. The receiver contains a photodetector, the data will be extracted by demodulation and will largely depend on the modulation technique used. Due to the line of sight of Li-Fi the data cannot be transmitted directly to every car using streetlights, as there will be obstruction from intermediate cars.
By allowing V2V communication between Li-Fi transceivers, this problem is resolved. In this scenario, one car receives data directly from the streetlight and then transmits the data to the other vehicle. Likewise, each vehicle transmits the data in its line of sight and the Li-Fi range depending on the intensity of the LED. This information is sent in an order of hierarchy which forms a dense communication network that manages traffic. If a car is stolen the address of the last streetlight or nearby vehicle can be tracked and it can ease the process of finding. The whole communication system can be made eco-friendly and energy efficient by using Building Integrated Photovoltaics (BIPV) as a power source.
PLATOONING USING LiFi- Vehicle To Vehicle Communication
There is a Li-Fi transmitter both in the front as well as at the back. The transfer of data can happen between any transmitter-receiver pair. A car in front will have a transmitter at the back that will send information to the cars behind about its speed and lane shift.
The information received by the car behind will go to its headlight. In case of sudden changes in speed or the application of break, the cars in the vicinity will be informed well in time.
LiFi can be used effectively for Platooning of Vehicles on the highway as it enables very fast communication between the vehicles in the line of sight.
The road conditions and traffic congestion details are sent to the vehicles from the infrastructure such as street lights. This information from one car is passed to the other creating an ad-hoc network of communication. Once a vehicle comes in the line of sight of the infrastructure, then it can directly transfer the data to the vehicle. If it fails, it would already have got the information from V2V communication. Simultaneously, each vehicle sends its vehicle number to the street light it passes and it can use that information for challans. Hence, in this case, the vehicle acts as the receiver and the street light acts as the transmitter unit.
Even though Wi-Fi has shortcomings, the Li-Fi technology does not aim to be the direct replacement of it. It just is an addition to the ongoing technology. The concept of Li-Fi is simple and with its extremely high speed, the processing time can be very fast. The only drawback in the vehicle to vehicle communication using Li-Fi is that,i t operates only in its line of sight. If we can increase the line of sight with the uninterrupted high-speed internet the technology can be tried in V2X. In the coming years, with more research into this technology, it can surely prove the Internet of Things to become a reality, where all electronic devices are used in communication.