Li-Fi (Light Fidelity) is a visible light wireless communication (VLC) technology equivalent to Wi-Fi. It can transmit light and light through the light of a light-emitting diode (LED) bulb, providing simultaneous illumination and wireless networking without electromagnetic interference. It will help alleviate the problem of the current surge in network traffic, and the development prospects are highly promising.
Today's world is inseparable from Wi-Fi, it is ubiquitous, neighborhood neighbors, cafés are free to offer, and smart phones are indispensable. We all know Wi-Fi, but do you know Li-Fi?
As the demand for mobile wireless access continues to grow, the congestion of mobile networks and Wi-Fi will continue to increase. Even if additional radio resources (RF) are added, it may not be enough to solve the problem. This phenomenon is called "Spectrum Crunch". But a more developmental solution is quietly appearing; according to statistics, more than 70% of mobile traffic comes from indoor environments, and Li-Fi can complement each other without interference in the light-emitting diode (LED) illumination area. The bandwidth is used to solve such spectrum shortages, and its huge data density capacity can also reduce the burden on existing RF networks.
Li-Fi is the abbreviation of Light Fidelity, which is equivalent to Wi-Fi's Visible Light CommunicaTIs (VLC) technology. It was invented by Harald Hass, chief scientific officer of PureLiFi and professor of the University of Edinburgh. This ground-breaking technology uses light waves from LED bulbs to transmit data, simultaneously providing illumination and wireless communication to the area of ​​use, providing an overwhelming number of wireless network links that enable network connectivity in all indoor environments or anywhere.
Visible light communication refers to any data communication transmitted through visible light, mainly relying on white light. The relative concept is infrared (Infra Red), which is the communication method currently used in remote control.
In addition to data communications, Li-Fi brings more advanced networking capabilities, including Data Roaming, Hand Over, and multiple access.
Li-Fi development background
Alexander Bell is best known as the inventor of the phone, but he was also the first person to show an optical communication system in 1880. In fact, just four years after inventing the phone, Bell set the world's first wireless phone. This call is made through the use of light, not radio, Photophone devices. But Bell needs to use daylight to transmit, so the range of use is quite limited.
Professor Harald Haas and his research team at the University of Edinburgh pioneered the concept of modern Li-Fi, and the research and development laboratory was even located in the Alexander Bell House (Bell was born in Edinburgh and alumni of Edinburgh). The emergence of Li-Fi is expected to solve the problem of increasing spectrum congestion. Professor Harald Haas demonstrated the Li-Fi technology for the first time at the TED Global Congress in July 2011. pureVLC was founded in 2012 and specializes in commercial Li-Fi.
Li-Fi's call for a more developmental solution
Like Wi-Fi, Li-Fi enables electronic devices such as computers, laptops, and smart phones to connect to wireless networks. Although Wi-Fi was originally developed only for the above devices, it has been widely used in connecting life with things: printers, TVs, speakers, headphones, and even sports shoes! Simply put, Li-Fi's role is the same as Wi-Fi, just using light waves as a medium, not a radio signal.
LED bulbs are rapidly replacing traditional fluorescent lamps because of their power saving and high security. Li-Fi uses light waves from LED bulbs to transmit data, so it can provide both illumination and wireless data transmission.
Imagine installing LED bulbs with Li-Fi technology in your living room, office, or even your desk and bedside lights. The place where the Li-Fi LED bulb is illuminated can also enjoy the communication convenience brought by Li-Fi.
The difference between Li-Fi and Wi-Fi
Li-Fi can turn LED desk lights into wireless access points like Wi-Fi routers. In addition to providing the advantages of lighting, what are the different functions?
Solve the blockage problem
Wi-Fi uses a relatively limited development of radio frequency (Radio Frequency) technology, such as computers, laptops, printers, smart TVs, mobile phones and tablets must compete for bandwidth. With the introduction of more Wi-Fi-enabled devices such as refrigerators, watches, and cameras, and the data offload from mobile networks, traffic congestion has become more serious, and the quality of information transmission has also been affected. Li-Fi uses the frequency of light waves, and its bandwidth is more than 10,000 times that of RF bandwidth, and does not conflict with Wi-Fi.
safety
It is well known that Wi-Fi generates Electromagnetic Interference (EMI), affects aircraft equipment and medical equipment, and is potentially dangerous for power generation, or oil and gas drilling. Li-Fi uses light instead of radio waves and is safe and immune to electromagnetic interference.
Data protection
Radio waves can penetrate walls and ceilings, but light does not. This area distinguishes between Wi-Fi and Li-Fi in terms of data protection. Hackers or intruders outside the building can sneak into indoor computers that transmit over Wi-Fi. However, information transmitted via Li-Fi can only be accessed within the range of LED lighting.
speed
The 802.11a/g standard Wi-Fi provides data communication speeds of up to 54 Mbps, and there are currently technologies that can increase the speed to 1 Gbps. However, the University of Edinburgh (a research partner of pureVLC, also the alma mater of Professor Harald Haas, the father of Li-Fi) has used monochrome light sources to demonstrate 3Gbps speeds. The use of full-color (red, green, blue) LED lights can be increased to 9Gbps.
How does Li-Fi work?
The standard LED bulb is controlled by the drive and the drive can switch and adjust the brightness. In an LED bulb using Li-Fi technology, the driver transmits the encoded data by controlling the LED lamp, and then receives the data using the photo sensor, and then decodes it. The concept of this mode of operation is similar to that of the Morse code, but at a speed of millions of times, it is already unrecognizable by the human eye.
The receiver has optical components and is fast enough to recognize the difference in light and dark of the light source. It also has sufficient ability to decode Li-Fi data and then transmit it to a connected device such as a laptop. The device can be equipped with both a transmitter and a receiver for two-way communication.
Prerequisites for Li-Fi
Li-Fi is a networked, mobile, high-speed visible light communication solution for wireless communications. In order to provide a comprehensive wireless network connection in an indoor environment, each Li-Fi system must have the following conditions:
high speed
The exponential growth in wireless data demand is not only due to increased users, but high-speed downlink services that require large amounts of bandwidth, such as video streaming and file downloading, further spur demand. Therefore, Li-Fi systems must provide high speed to maintain existing network services and satisfy users.
Bidirectional
In order to provide a stable network connection, there should be a reverse link from the device side to the network side, so that the device can request or modify information, and provide the function of uploading photos and videos in the era of information explosion. Therefore, in order to provide complete network operation and user experience, two-way communication is an essential requirement.
Multiple access
For RF networks to serve a large number of users, each station's cellular base station (serving hundreds of mobile communication users) and each Wi-Fi access point (serving dozens of user devices) need to be connected to each side of the network. Share time or frequency resources. In theory, a particular area containing several users and devices can provide light through a single lighting device, and adding Li-Fi to this source would require similar resource sharing. This is called "multiple access" and helps extend wireless access to the lighting space and to all users within the network.
Mobility / Handover
Finally, because light is inherently "directional" to the opposite of RF signals, it takes several lighting devices to provide sufficient light in any space, both indoors and outdoors. Since each light source is a wireless access point in a Li-Fi network, how to make the user enjoy a complete and continuous communication connection during the mobile process becomes the most important issue in network operation: the network must To be able to "change hands" between access points. Without this feature, mobile communication users must re-establish links with various network access points and restart the information transmission process on the device.
The common goal of the above conditions is to reduce interference, improve efficiency, and improve the user experience. For the operation of Li-Fi, it is a fairly basic requirement.
B&R Power Panel PP35 Touch Screen panel
Power Panel PP45 touch screen panel for B&R HMI repair
B&R Automation Power Panel PP65 touch panel screen
Power Panel PP100 HMI Touch Panel screen
Power Panel PP200 touch screen glass for BR automation repair
touch screen for Power Panel PP300 touch panel repair
B&R automation Panel PP400 touch screen panel
Power Panel PP400 embedded touch screen membrane
touch panel for Power Panel C70 Touch Screen Repair
membrane switch for B&R Power Panel PP65Keyboard membrane for Power Panel PP100 repair
Power Panel PP200 membrane keypad repair
membrane keyboard for Power Panel PP300 repair
B&R automation Panel PP400 membrane keyboard
Power Panel PP400 embedded membrane keypad repair
keypad for Power Panel C70 membrane switch repair
BR PP15 membrane keyboard switch keypad.
PHARMA FLEX touch screen panel glass repair
METTLER TOLEDO touch screen panel repair
GARVENS HMI Touch Screen panel glass
HMI Touch Panel Repair,Touch Membrane Repair,Membrane Keyboard Repair,Touch Screen Repair
GUANGZHOU VICPAS TOUCH TECHNOLOGY CO.,LTD , https://www.touchsuppliers.com