The LiFi Technology

INTRODUCTION 

The LiFi technology invented by the by the German physicist Prof. Harald Haas in the year 2011. He proposed the LiFi technology, provides data transmission through the beam of light by sending data through a Light Emitting Diode (LED) that varies in intensity faster than the human eye can catch. Because of increasing demand in the wireless data communication. The available radio spectrum below or up to 10GHz nowadays become insufficient. The wireless communication industries have responded to this challenge by taking into consideration the radio spectrum above 10GHz. However, higher frequencies (f), means that the path loss (L), increases according to the Friis free space equation (L ∝ f 2) [1]. As transmission of data from the one place to another is one of the major activities day-today, in present days the current wireless networks that connect us to the internet are slow if in that networks multiple devices connected. And the solution to this problem is by the use of LiFi. LiFi technology provides data transmission through the light beam by sending data through LED.

Why Need LIFI ? 

• LiFi Technology is based on all various kinds of light.  
• In the worlds light is present everywhere, and there are many bulbs, the only thing is to replace by LED’s for the data transmission. 
• Light has 10000 times wider bandwidth than radio waves [4] that proves better capacity. 
• Light cannot penetrate the walls, which provides the security. 
• LiFi is very cheaper for data transmission purpose. 
• WiFi cannot be use under water. But, LiFi can be, light can be used under the water. 
• By using LiFi technology, every street light anywhere would be free data hotspot. 

What is LiFi ? 

LiFi, also known as "Light Fidelity" is a wireless optical networking technology, which uses light-emitting diodes (LEDs) to transmit data. In 2011, professor Harald Haas made a LiFi demonstration at the TED (Technology, Entertainment, Design) Global Talk on Visible Light Communication (VLC). VLC uses light as a medium to deliver high-speed communication like 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. How does LiFi work? LiFi is a high speed, bidirectional, and fully networked wireless communication of data using light. LiFi constitutes of several light bulbs that form a wireless network. When an electrical current goes through to a LED light bulb, a stream of light (photons) emits from the lamp. LED bulbs are semiconductor devices, which means that the brightness of the light flowing through them can change at extremely high speeds. The signal is sent by modulating the light at different rates. The signal can then be received by a detector that interprets the changes in light intensity (the signal) as data. Also when the LED is ON, you transmit a digital 1, and when it is OFF, you transmit a 0. 

LiFi Benefits

The primary benefits of LiFi are as follows: 

• Security: Provides entirely secure access. Where there is no light there is no data. 
• Safety: Does not produce electromagnetic radiation and does not interfere with existing electronic systems. 
• Localisation: Allows localisation due to the small coverage area of LiFi access point - localisation can be used for very precise asset tracking. 
• The terms WiFi and LiFi possess similarities (both are wireless methods of data transmission) but are fundamentally different in that WiFi uses radio waves whereas LiFi uses light.

                                        

• Data density: Provides ubiquitous high-speed wireless access that offers substantially greater data density (data rate per unit area) than RF through high bandwidth reuse.

Advantages of LiFi

• There are many different advantages offered by using LiFi. One of its biggest benefits come with its efficiency. Since LiFi makes use of VLC technology, which in turn makes use of highly-efficient LED bulbs, users are able to enjoy lower costs in terms of energy consumption. Additionally, they only require working LED lights, which are already available within most households and other establishments, allowing for additional savings in terms of installation costs.
• Another big advantage of LiFi is that the usage of light allows LiFi connections to occur almost instantaneously because light travels at extremely fast speeds. This results in faster transmission of data and faster internet connections – about 100 times faster than speeds achievable by WiFi.
• Because there are already 14 billion light bulbs all over the entire world, its availability is never in question as there can be as many LiFi networks available as there are light bulbs.
• Lastly, the nature of visible light is that it cannot penetrate opaque walls. This means that as long as rooms are covered by opaque walls, light is confined within the space in which it is shone, thereby confining the connection to the space in which it is shone. This prevents unauthorized access to the LiFi connection, adding another layer of security to the network.

Disadvantages of LiFi

• There can be many disadvantages to LiFi, as well. Its biggest drawback comes in the form of infrastructure (or lack, thereof). Since LiFi technology is a relatively new concept and is currently in its introductory stage, the infrastructure necessary to implement the technology in a large enough scale is still virtually non-existent. This means that plenty of time is still required before the general public can enjoy LiFi technology.
• Another disadvantage is that the light source will need to be constantly turned on in order to provide network access. This problem can be solved by dimming the light enough to levels that the human eye can perceive as turned off, but are actually still on. In cases where dimming the light is out of the question, however, this could be a problem.
• Another perceived disadvantage of LiFi connections is that because it relies on light to transmit data, it becomes highly susceptible to outside interference. Photodiodes are able to pick up light from competing sources of light such as sunlight and other forms of illumination. This could potentially create noise within the receiver and cause disruptions to the network. In most LiFi systems, an optical filter has been installed on photodiode devices in order to filter noise so that the receiver can only pick up signals coming from the transmitter.
• Lastly, users are rendered immobile when using LiFi systems due to the limited range of the signal given off by light bulbs. This is, of course, countered by installing multiple LiFi systems within large spaces, creating as many connections as there are light bulbs.

LiFi Applications 

LiFi can be used for so many applications and the list is increasing every year. 

  

1. Li-Fi in Hospitals

Because of the non-interference of Li-Fi with radiofrequency devices, Li-Fi can be safely used in many hospital applications. For example, in corridors, waiting rooms, patient rooms and operating theatres, Li-Fi technology will allow a light communication network, which will remove electromagnetic interference issues from smartphones and the use of Wi-Fi in hospitals. Li-Fi can be used for real-time monitoring and report of patient movement and vital signs without the need for wires.

Li-Fi can also enable patients on their beds to connect to internet news, emails, video games and social media platforms through their smartphones. This helps them pass the time during their stay. For medical workers, Li-Fi will enable the tracking and relocation of the positions of critical medical devices, especially those regularly shared by different departments. 

 2 Li-Fi in Retail 

Li-Fi can help to direct shoppers from the time they enter the shop. It can also help them to locate specific products in the store, collect digital coupons, check store promotions, check stock availability of some products on the shelves, engage in-store online services through their smart devices and improve their store experience. For retailers, Li-Fi can enable them to send promotions to shoppers' smart devices, displaying promotions and offers. Li-Fi can also help retailers understanding behaviour anonymously for most customers, understanding the demographics of their shoppers, enabling target marketing campaigns, conducting display advertising campaigns and checking real-time stock availability. Li-Fi will bring an opportunity for shopping malls and centres to be a frontrunner in gaining an understanding of their customers and ultimately influencing them. 

 3. Li-Fi in Schools 

The right wireless network is a crucial component to provide new learning experiences by connecting students and teachers to smart technology, enabling learning applications on any mobile device. Li-Fi can also provide seamless network connectivity and security throughout the whole school, from the classroom through to university dorms. Some schools have even started trialling Li-Fi technology in classrooms.

Conclusion

When looking at the comparisons between WiFi and LiFi, it would be very difficult to choose one over the other as both have their own merits – and their own disadvantages. That is why a different mind-set needs to be adopted and look at these pieces of technology in a different way.

A big misconception about LiFi systems is that it was created to replace WiFi altogether. Considering that most of the existing infrastructure has already been built to accommodate RF technology, it would be very costly and tedious to replace all of that infrastructure to give way to a newer technology. For this reason, LiFi needs to be looked at as a complementary technology that aims to improve the performance of the existing technology and provide relief to the already congested radio spectrum used to provide WiFi connections.