"Wi Fi has had a huge impact on the use of mobile computing, enabling employees to access the company's network anywhere, and coffee shops can become the office of independent staff. However, Wi Fi also has its disadvantages, so a new standard was born: Li fi. If it can be successfully listed, it will be able to fill the gap of Wi Fi technology.
The problem with Wi Fi is that the signal coverage is small, especially facing the wall, and it is also easy to be hijacked by hackers. Although the bandwidth has increased in recent years, it is very easy to slow down when too many people access Wi Fi at the same time. Adding more Wi Fi is only a partial solution at most. It can not solve the security problem, but only partially solve the scalability problem.
Li fi or visible light wireless communication, which is an emerging wireless protocol, uses visible spectrum to provide wireless network access. Li fi transmitters use LED lights to adjust light intensity, mostly beyond the range that our eyes can perceive, and are read as data by photosensitive receivers. Since LEDs have used chips to control their output, they can modulate up to millions of times per second. In theory, the data transmission speed can be 100 times faster than Wi Fi.
But Li FI is not a substitute for Wi Fi, but a supplement. Whether we use smart phones, tablets or laptops, the two will exist at the same time, which requires a special receiver and transmitter to send and receive Li fi signals. A special encoder / decoder chip is also needed to convert the optical signal into data.
Li FI is still an ongoing technology, but its inventors say IEEE is considering incorporating it into the 802.11 Wi Fi standard“ The introduction of light emitting diodes (LEDs) for general lighting has generated increasing interest in using the visible spectrum for wireless communication. " However, the standards body is still seeking feedback from its members. "It's hard to get standards recognition," said will Stofega, project manager for mobile device technology and trends at IDC“ There are always ecosystem and political interests. I always think it needs a lot of work, but Li wi is the most promising alternative connection technology. "
Stofega warned that vested interests would fear and doubt any technology that could potentially threaten their income. Just as some 4G manufacturers oppose 5g because they threaten their market dominance, Li fi may also face opposition. "There will be people on Wi Fi forums who say Li FI is a bad idea," he said
Shortage of wireless spectrum resources
Using optical data transmission is nothing new; This is how the TV remote control works. However, the remote control uses infrared, and its distance and transmission capacity are strictly limited.
Professor Harald Haas, chairman of mobile communications at the University of Edinburgh and co-founder / chief scientific officer of pureli fi, first proposed Li fi in 2011. The company tried to bring Li fi to the market. Haas said that the shortage of wireless spectrum resources inspired him to create Li fi. Haas once worked in 4G at Siemens. He realized that wireless spectrum was not enough for the multimedia era. Since then, he developed the world's first Li fi wireless transmitter, and cooperated with French lighting manufacturer lucibel to manufacture the first fully integrated Li fi lighting lamp, which was displayed at this year's Mobile World Conference.
"Li fi today is like Wi Fi 15 years ago, and in five to ten years, Li fi will be as ubiquitous as Wi Fi," he said
Anand oswal, senior vice president of engineering of Cisco enterprise network group, said that Cisco believes that Li FI is an exciting emerging technology with great potential. Cisco's strategy is to establish Li fi technology and finally develop products, but he added: "we are still in the exploration stage, and Cisco has not made any decision on Li fi products and solutions."
A potential integration area of Cisco is its digital construction plan, which is a set of solutions. It cooperates with suppliers of Philips, microchip, Cree and Molex to provide power lighting systems for enterprises by using Cisco's innovation of power over Ethernet (POE) and general Ethernet power supply (upoe).
"The ability to convert every light in the enterprise into wireless communication media is the future evolution trend of this solution," oswal said. Cisco is working with partners to explore how to seamlessly integrate technology into Cisco's wireless infrastructure“ This will enable Li fi technology to have decades of innovation leading the field of Wi Fi. "
Jerry Johnson, President and CEO of EMC, a supplier of energy control and IOT solutions, said that retailers are very interested in Li fi as a potential alternative to Bluetooth beacon technology. He also sees the interest of government, airport and commercial space and building owners who want to supplement Wi Fi or use Li fi in conference rooms.
EMC plans to become a nationwide distributor of Li fi bulbs and has deployed them at 80 test sites. "I think there will be a combination of Li FI and Wi Fi in the future, and Li fi will dominate," he said“ Li fi will greatly improve the overall bandwidth, speed and reliability of the network, not to mention the communication capability. " Some companies are testing Li fi, but now they don't disclose relevant information. He added that EMC's own research shows that Li FI can transmit data 100 times faster than traditional Wi Fi.
How does Li fi work
The key difference between a conventional LED lamp and a bulb supporting Li FI is that the driving circuit in the Li fi bulb sends and receives wireless signals and encodes data with light of different intensities. Some lights can be connected to the network through a connecting CAT5 cable, while others can receive data through a power cord connection.
Li fi creates a two-way link and uses special photodetectors at both ends: one end is in the LED light of the room, and the other end is on the mobile device or plugged into the wireless transmitter of the mobile device. The wireless transmitter sends data back to the LED. When you move in a room with multiple Li fi lights, the device will automatically detect where the strongest signal comes from and transfer it to the light source, so the signal is always connected and in the best state.
Haas estimates that smart phones and other devices will begin to launch Li fi signal chips in two or three years. Stofega said he did not hear mobile manufacturers interested in Li fi, and most manufacturers are focusing on 5g.
He said: "it's not difficult or expensive, but mobile manufacturers will want Li fi to be verified before deployment“ He said“ I don't even want to devote myself to 5g because they are still setting standards. "
However, Li FI is different from Wi Fi in several key aspects, such as range, anti-interference and throughput. One of the limitations of wireless spectrum is that when you rise from 2.4GHz to 5GHz, you will lose coverage. If it is higher than 5GHz, this range will be further reduced. In theory, the throughput of Li FI is much higher than that of Wi Fi. Pureli fi has just released a product that enables a single small micro led to transmit at 8 Gbps. Now the 2.4GHz and 5GHz bands have been saturated with existing devices such as wireless phones, Bluetooth devices and Wi Fi, not to mention new technologies such as augmented reality, virtual reality, driverless cars and billions of Internet of things devices.
Since the visible light is completely different from other types of RF frequencies, there is no possibility of signal interference, and the visible light is 1000 times that of the entire 300 GHz radio spectrum. Haas points out that led lights do not even need to be bright enough to be visible.
Finally, Johnson said that adding Li fi to existing devices is also cheaper“ The cost of technology has fallen so fast that there is no challenge in adding Li fi to the device. " Li fi will use the camera technology of existing devices. Cameras in laptops or smartphones will do well. They only need a decoding chip, which must be added to future devices. However, if Li fi becomes part of the 802.11 specification, the Wi Fi chip will also be able to process Li fi signaling.
Lighting industry
Hass stressed that Li FI is a supplement to Wi Fi and 4G / 5G, not a substitute“ Li FI can be used for street lights as an access point for smart city applications, "he said“ The indicator lights of household appliances can connect these devices to the Internet through ceiling lights, while wearable devices with integrated LEDs can monitor health parameters and send data to the Internet. "
A disadvantage of Li FI can also be considered an advantage. Because it uses the visible spectrum, Li fi cannot penetrate the wall. In many cases, this is a problem, but for secure connections, it is an advantage. Li fi said that people interested in security, especially the military, are like being able to build a wireless network that can be locked in a room, as long as there are no windows on the wall.
Cisco is still in the stage of exploring Li FI and has not made any commercial decision on the technology. The company believes that Li fi deployment will start with security and security related niche markets“ In my opinion, Li fi will achieve critical development when the endpoint ecosystem of visible light communication becomes more mature, "he said“ Cisco can see the future of selling Li fi light sources to enterprises that provide specific throughput and integrate seamlessly into Cisco's wireless architecture. "
Severe challenges facing Li fi
Like any new technology, Li fi faces challenges. At least Wi Fi has been fully supported by Intel. Li FI is only driven by university professors in Scotland, even if he has allies such as Cisco and BT. Haas said that they cooperated with pureli-fi, but would not specify the depth of cooperation. "There are several obstacles to the widespread adoption of any new technology," oswal said“ However, these are often just the synchronization of technological progress and marketization. "
Stofega believes that if IEEE takes Li fi as part of 802.11 specification, it will play a decisive role. Because Qualcomm, Intel and other manufacturers will support 802.11 chips. Then it's just a matter of LED bulb deployment. In order to succeed, oswal said that it must fulfill its commitment to throughput and scale; Endpoint equipment must enter the market; And there needs to be a supplier ecosystem that supports Li fi to build lights.
Jack gold, President of J. gold associates, a mobile consulting firm, expressed doubts“ Visible light communication has been tried for several years, which is not new. "You can get a lot of bandwidth, but it's not as simple as it sounds." And Wi Fi works well, almost everywhere. If the technology you use is quite reliable, you can propose a new technology to replace or supplement, but this technology must be better, but there are still many problems to be solved in Li fi.
Original link: https://www.eeboard.com/news/li-fi/
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