What is Li-Fi? What are its Pros, Cons & Applications?

What is Li-Fi? What are its Pros, Cons & Applications? (Last Updated On: March 21, 2019)

What is Li-Fi ?

What is Li-Fi ? The term LiFi was coined by pureLiFi’s CSO, Professor Harald Haas, at a TedGlobal Talk back in 2011 where he demonstrated LiFi for the first time.

LiFi is high speed bi-directional networked and mobile communication of data using light. LiFi comprises of multiple light bulbs that form a wireless network, offering a substantially similar user experience to Wi-Fi except using the light spectrum.

LiFi is a category of Optical Wireless Communications (OWC). OWC includes infra-red and ultra-violet communications as well as visible light. However, LiFi is unique in that the same light energy used for illumination may also be used for communication.

How does Li-Fi works:

LiFi allows for data to be transmitted by modulating the intensity of light, which is then received by a photo-sensitive detector. The light signal is then demodulated into electronic form. This modulation is performed in such a way that it is not perceptible to the human eye.

What is Li-Fi? What are its Pros, Cons & Applications?

What is Li-Fi? What are its Pros, Cons & Applications?

LiFi can work indoors, outdoors, with the lights dimmed and is not strictly line-of-sight technology. pureLiFi’s technology is also LED agnostic which means it works with many off-the-shelf LED’s. The way LiFi works is simple but powerful. When a constant current is applied to an LED light bulb, a constant stream of photons are emitted from the bulb which is seen as illumination.

LED bulbs are semiconductor devices, which means the current, and therefore the illumination can be modulated at extremely high speeds which can be detected by the photo-detector. Using this technique allows for high-speed information can be transmitted from an LED light bulb.

Radio frequency communication requires radio circuits, antennas and complex receivers, whereas LiFi is much simpler and uses direct modulation methods similar to those used in low-cost infrared communications devices such as remote control units. LED light bulbs have high intensities and therefore can achieve very large data rates.

Applications & Benifits of Li-Fi:

The applications for LiFi are limitless. Anywhere there is an LED light there can be data. LiFi is a platform technology that will extend the capabilities of wireless communications to places beyond even our current conception.

Today there are real life applications and benefits for implementing LiFi. LiFi can enable secure wireless communications, connectivity in RF hostile environments such as petrochemical plants and hospitals. LiFi also provides high speed, dense and reliable networks for enterprise environments and a pathway to enable smart buildings, transport, cities, and nations.

1. Security
The inherent security advantages of using light for wireless communications allow companies to enhance security for their wireless networks significantly. The ability to strictly define the communication area of a LiFi access point allows precise partitioning of the office environment. In addition, the technology requires proprietary hardware before anyone can access the system.

2. Smart Lighting
Anywhere there is LED lighting infrastructure there can be a wireless LiFi communication network. That LiFi network can provide added value providing enhanced efficiency and control. Each LiFi access point (LED Light) in a LiFi network has a unique IP address allowing facility and IT managers the ability to harness the power of a small cell network.

3. Hospitals & Healthcare
LiFi offers an unprecedented opportunity for connectivity within hospitals and healthcare facilities. LiFi does not emit electromagnetic interference and therefore does not interfere with medical instruments, nor is it interfered with by MRI scanners.

4. Smart Transport
LiFi can not only provide high speed, secure and reliable wireless communications for users of transport, LiFi can also enable vehicle to vehicle communications.

5. Smart Cities
LiFi can enable the realisation of truly smart cities. Street lights, building lights, and transportation lighting can all communicate wirelessly. LiFi can relieve public wireless congestion as an offloading facility for radio frequencies.

6. Smart Home & Lifestyle
LiFi in the home will enable simple, secure, reliable and robust wireless communications. Similar to the enterprise environment LiFi can offer data aggregation and wireless offloading. Smart homes can be truly wireless, and users can intuitively understand the best coverage locations by seeing the light. No longer will home users need to worry about “man in the middle” attacks, as they can simply draw the curtains and shut their doors to secure their LiFi networks.

Pros of Li-Fi:

1. Secure
Light can be contained. Light cannot travel through walls, which means a LiFi signal can be secured in a physical space. pureLiFi’s technology also enables additional control as data can be directed from one device to another. Users can see where data is going.

2. No Interference
Radio frequency technology such as Wi-Fi is vulnerable to interference from a wide range of devices such as cordless phones, microwaves and neighbouring Wi-Fi networks. LiFi signals can be defined by the area of illumination, which means interference is much simpler to avoid and even stop altogether. This also means LiFi can be used in RF hostile zones such as hospitals, power plants and aeroplanes.

3. Data Density
Data density offers a greater user experience as it reduces the need to share the wireless bandwidth with other users. LiFi can achieve approximately 1000 times the data density of Wi-Fi offering more data per square metre. This is an important factor for wireless efficiency.

4. Location Services
LiFi systems are fully networked, and each LiFi enabled light has it a unique IP address which means advanced geofencing can be deployed simply in a LiFi network.

5. Efficiency
LiFi allows the repurposing of light for communications as it uses the same infrastructure. LED lights are already widely efficient, and LiFi gives them another purpose, connectivity.

6. Smart Lighting
Any private or public lighting including street lamps can be used to provide LiFi hotspots, and the same communications infrastructure can be used to monitor and control lighting and data.

Cons of Li-Fi:

1. Reliance on Light Sources
With Li-Fi, light must be available 24/7. You cannot switch off the light; you can only dim it if you want uninterrupted transmission of data. This seriously limits the locations and situations in which Li-Fi may be used.

2. Limited Range
This range for Li-Fi is limited as the light signal cannot penetrate across walls. While this makes Li-Fi secure, the limited range can be a nuisance for some people.

Frequently Asked Questions (FAQ):

1. How much does Li-Fi cost?

These installations are priced based on individual requirements. PureLiFi is currently working towards miniaturisation of LiFi technology. Ultimately the end goal is to have LiFi in every mobile device. This means that the technology will be affordable for integration into handsets, tablets and laptops. Ultimately the end consumer will see minimal or no cost associated with LiFi as the goal is to have LiFi embedded in every wireless mobile device.

2. Can we see LiFi lights flicker?

The LED lights used to transmit LiFi signals are modulated at such a fast rate that the eye cannot perceive the modulation or “flicker”. This is similar to the way our eyes do not interpret the break between film frames in a motion picture. Just as you see a smooth motion on the cinema screen, you will see an uninterrupted source of steady light streaming from a LiFi enabled luminaire.

As a comparison, the lowest frequency at which the lights are modulated is 1MHz and this is 10,000 times higher than the refresh rate of our computer screens.

3. How does LiFi work in a bright room with sunlight?

LiFi can operate in daylight and even in direct sunlight conditions, as the modulated light can still be detected. LiFi relies on detecting the fast changes in light intensity and not on the absolute or slowly varying levels caused by natural disruptions in daylight or sunlight. LiFi technology modulates the light at very high rates and sunlight is constant light and therefore can be filtered out at the receiver.

4. How does LiFi work when you turn off the lights?

If all power to a light is turned off then there is no LiFi. However, LiFi technology can be enabled to dim low enough that a room will appear dark and still transmit data. There is consistent performance between 10 and 90 percent illumination.

There are also other options for using invisible parts of the light spectrum such as infra-red, which is currently already being used for sending information back to the lightbulb (uplink).

5. How is LiFi more secure than other wireless technologies?

LiFi is significantly more secure than other wireless technologies because light can be contained in a physical space. Our doors and windows can be shut, and physical barriers and adjustments can be implemented to contain and protect the light. We can create the conditions that allow us to shut the door on our wireless data.

It should be understood that the existing security protocols for encryption and authentication can be leveraged in LiFi systems to provide even more secure wireless systems.

6. Is LiFi a bidirectional technology, and what does that mean?

LiFi is bidirectional wireless communications technology that allow high speed transmission in both uplink and downlink simultaneously.

7. Is LiFi a line of sight technology?

Light bounces off of surfaces and therefore LiFi is not strictly a line-of-sight technology. LiFi is a cellular communication system and the data rate is not dependent on the line of sight but on the signal quality at the device. Signal quality can be defined by the ratio of the desired data vs any interfering data and noise.

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