Indroduction,Advantages and limitation of Li-Fi

Li-Fi, like Wi-Fi, enables electronic devices like computers, laptops and smartphones to wirelessly connect to the Internet.

Father of ‘Li-Fi’, Prof.Harald Hass coined the term Li-Fi to mean ‘light fidelity’ (visible light communications (VLC) closely equivalent to Wi-Fi)

In simple terms, Li-Fi is equivalent to Wi-Fi, but using light waves instead of radio signals.

Li-Fi is well-defined as the networked, high-speed VLC solution for wireless communications.

What is the Need Of Li-Fi ?

Wi-Fi uses radio frequencies, and these are very limited. Devices –computers, laptops, printers, smart TVs, smartphones and tablets –must compete for bandwidth. The emergence of more and more Wi-Fi-enabled devices e.g. refrigerators, watches, cameras, and offloading from cellular is causing congestion, and degrading data communications.

With the help of Li-Fi,we can resolve this spectrum congestion.

Li-Fi uses the frequencies of light waves, which are up to 10,000 times more plentiful than radio frequencies and do not compete with Wi-Fi.

Thus , Li-Fi was developed as a solution to the growing radio spectrum congestion problems.

Realisation Of Li-Fi

Imagine a modern LED light bulb – fitted with Li-Fi technology – in your living room, or office, or in a lamp on your desk, or by your bedside.

So with the help of Li-Fi enabled LED, you can communicate via Li-Fi and it provides an added advantage of Illumination.

Does it seems interesting, isn’t it?

The difference between Li-Fi and Wi-Fi is …?

Li-Fi can turn an LED lamp into a wireless access point similar to a Wi-Fi router, so apart from the added advantage of illumination, how do they differ?

1. Wi-Fi uses radio frequencies, and these are very limited.

While Li-Fi uses the frequencies of light waves, which are up to 10,000 times more plentiful than radio frequencies and do not compete with Wi-Fi.

2. Wi-Fi creates Electromagnetic Interference (EMI), known to interfere with airplanes instruments and is potentially dangerous in hazardous operations.

While Li-Fi uses light instead of radio waves, which is intrinsically safe and does not create EMI.

3. Radio waves pass through walls and ceilings While Light doesn’t. Therein lies the difference in data security between Wi-Fi and Li-Fi. An intruder or hacker, outside a building can tap into the Wi-Fi data communications of computers inside the building. Data communicated via Li-Fi can only be accessed where the LED light illuminates.

4. Wi-Fi standard, 802.11a/g, provides data communication rates up to 54Mbps. However, there are techniques available to extend this to 1Gbps.

“The father of Li-Fi” have already demonstrated 3Gbps on a single col On a single LED with full color (R,G,B) this could communicate a speeds to 9Gbps.

How Does It Work?

Standard LED light bulbs are controlled by a lamp driverthat turns the LED on and off, or dims and brightens it. With Li-Fi enabled LED light bulbs, the driver is used to transmit encoded data by controlling the LED light.

An optical sensoris used to receive the data, which is then decoded. This is conceptually similar to Morse code – but at rates of many millions of times a second, which is imperceivable to the human eye.

The receiver has optics, and is fast enough to ‘see’ the light dimming and brightening, smart enough to decode the Li-Fi data, and then deliver it to the attached device such as a laptop computer.

Devices can include both a transmitter and receiver to enjoy two-way communications.

Advantages


  • Data Transmission is at High Speed (9GBps).
  • Li-Fi is more Secure as compared to Wi-Fi.
  • Li-Fi is intrinsically safe bcz, It does not produce EMI.
  • Bi-directionality is, perhaps, the easiest feature of Li-Fi to overlook.
  • Its enormous data density capability will substantially reduce the burden on existing RF networks.
  • Low Cost
  • Easy to Use

Disadvantages

  • Lack of multiple access capabilities.
  • Eliminates the possibility of mobile wireless access.Here a mobile user will need to constantly re-establish connection with each network AP, and re-start its running information transfer on the device.
  • It can’t pass through the wall.
  • High Installation cost for VLC system.

Applications

Medical Field:Li-Fi emits no electromagnetic interference and so does not interfere with medical instruments, nor is it interfered with by MRI scanners.

Underwater Communications: Due to strong signal absorption in water, RF use is impractical. Acoustic waves have extremely low bandwidth and disturb marine life. Li-Fi provides a solution for short-range communications.

Vehicles & Transportation:LED headlights and tail-lights are being introduced. Street lamps, signage and traffic signals are also moving to LED. This can be used for vehicle-to-vehicle and vehicle-to-roadside communications. This can be applied for road safety and traffic management.

Location Based Services (LBS):Highly accurate location-specific information services such as advertising and navigation that enables the recipient to receive appropriate, pertinent information in a timely manner and location.

INDOOR APPLICATIONS:Li-Fi can be used in your living room, or office, or in a lamp on your desk, or by your bedside.

With over 70% of mobile traffic originating from indoors, Li-Fi can be used to reduce the burden on existing RF networks.

Lighting Point as HOTSPOT:Used as a Hotspot in Shopping Malls, BUS STOP etc.
RF Spectrum Relief:Li-Fi is particularly suitable for many popular internet “content consumption” applications such as video and audio downloads, live streaming, etc. In this way, the majority of the internet traffic is off-loaded from existing RF channels, thus also extending cellular and Wi-Fi capacities.

Smart Lighting:Any private or public lighting including street lamps can be used to provide Li-Fi hotspots and same can be used for ILLUMINATION Purposes.

Mobile Connectivity: Laptops, smart phones, tablets and other mobile devices can interconnect directly using Li-Fi. Short range links give very high data rates and also provides security.

Aviation:Li-Fi can be used to reduce weight and cabling and add flexibility to seating layouts in aircraft passenger cabins where LED lights are already deployed. In-flight entertainment (IFE) systems can also be supported and integrated with passengers’ own mobile devices.

Li-Fi networks can, and will, provide the perfect complement to today’s RF infrastructure and further enhance mobile communications.

As The spectrum crunch is a coming disaster, and indoor communications is experiencing over 70% of Mobile TRAFFIC,

So,The only solution to this is, a high-speed, bidirectional, wireless network: a Li-Fi system.


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