Li-Fi is coming! The light bulb is faster than 5GWi-Fi

Now the family began using a LED lamp more and more, with the development of technology, the LED lamp will also open a new way for wireless devices to access the wireless network, and the LED lamp brought by Li-Fi (Light Fidelity, visible light wireless communication) wireless network regardless of network bandwidth or response speed faster than the Wi-Fi wireless network. At the very least, Aydin Hass, President of the school of mobile communications at Fort Worth University, Harald.

Haas says, "all the components, all of the technology already exists. Now you just need to put them together to get the Li-Fi optical wireless network running. "

Haas research group in addition to Edunburgh University researchers, from the University of Cambridge, University of Oxford, and University of Saint Antoine Drewsen lamp University researchers, this topic has lasted 4 years, the capital of British Engineering and Physical Sciences Research Council 5 million 800 thousand pounds of support. The research group of parallel ultra visible light communication technology (ultra, parallel visible light communication), a variety of colors that the use of lighting to provide high bandwidth network connections within a few meters. Researchers said that Li-Fi optical wireless network can be supplemented or even partially replace the traditional Wi-Fi network. But instead of Wi-Fi, radio frequency technology is a very difficult war.

At the IEEE conference in October this year, members of the joint task force showed what they had achieved. They show the team using commercial RGB LED light bulb as a signal transmitter and a diode to detect light. As a result, they created a device capable of receiving and sending data, data throughput reached 100Mb/s. If the signal is fired only in one direction, the rate will increase to 155Mb/s.

But Haas said that the current LED technology and the LED lamp at the same time as the transmitter and receiver, so the speed is not fast. Members of the joint research group has developed a better LED lighting, the light output is only 5 MW LED lights, but also the use of a high bandwidth diode as a receiver, the data transmission rate is close to 4Gb/s. After using a simple lens to enhance the distance, the LED lamp in the range of 10 meters of data transmission rate can reach 1.1Gb/s. Haas also said that they will soon increase the rate to 15Gb/s. 802.11ad Wi-Fi standard uses 60GHz RF band, the rate is about 7Gb/s, so, Li-Fi optical wireless network speed is two times the rate.

They used avalanche photodiode (avalanche photodiode) as a wireless signal receiver for Li-Fi devices. In avalanche photodiodes, when a single photon strikes a receiver, it causes an avalanche of electrons, increasing the intensity of the signal. Haas's team developed the first integrated avalanche photodiode CMOS receiver in the Li-Fi research and development center in Li-Fi. There are 49 diodes on the chip, which is only 7.8 mm2.

At the same time, Germany's Fraunhof research center in 2014, the Munich Electronics Fair showed Li-Fi wireless hotspot. Frank, director of the Fraunhof Institute of the project, said Deicke, the system is more like an infrared system, target industrial customers rather than ordinary consumers. The hot spot data connection, the rate can be up to 1Gb/s.

Deicke said, "the transmission rate of more than USB lines. For the vast majority of wireless technologies, such as Wi-Fi and Bluetooth, can exceed USB is a big challenge. "Deicke said that there is another advantage of the technology, Wi-Fi signal transmission delay is generally calculated in milliseconds, and the delay of Li-Fi is calculated in microseconds (1000 microseconds = 1 ms). In industrial applications, data transmission needs to go through sensors, actuators, control units, so low latency, high rate of Li-Fi is more useful than Wi-Fi. "We don't want to replace Wi-Fi," he said. This is not our goal. "

But Deicke says Li-Fi can complement existing communications technologies, including Wi-Fi and ethernet. So far, his team has not applied the technology to common bulbs.

European researchers and Internet companies are preparing to push Li-Fi technology to the consumer market. This group of people is working on a project called advanced integration and management innovation network design (ACEMIND), which can help users manage the local network of families or small businesses. ACEMIND includes a number of projects, testing a variety of technologies, including Li-Fi. Dmitris, a researcher at the University of Athens who took part in the project, said that Li-Fi technology would be able to enter the practical stage in the next 5 years in the next years. "Li-Fi has a lot of advantages in some electromagnetic sensitive areas, such as hospitals, cabin, power station, etc.. "

Haas is targeting the larger market. He hoped that the LED light from the source of the evolution of light, like the mobile phone, has now evolved into a mobile computing device. "In the next 25 years, every bulb in the home will have the same computing power as today's cell phone. In the future, lighting is only a function of the light bulb. "

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