By James Zarharchuck, Data Operations Professional, Walter E. Washington Convention Center
Harald Haas, the co-founder of PureLiFi, coined the term LiFi at a TED Global Talk where he discussed the idea of supporting wireless communication through lights. The future may soon consist of LED light bulbs connected to a wireless mesh network bringing high-density connections to residential areas and eliminating wireless communication dead zones.
Visible Light Communication (VLC) is not a new technology. In fact, it is quite old. Its history can be traced back in the 1800s with Alexander Graham Bell’s photophone, which used modulated sunlight to transmit speech. VLC is the transfer of information through the use of the visible light portion of the electromagnetic spectrum.
LiFi, one subset of the optical wireless communication technologies, uses VLC between 400 and 800 THz—much higher than most used radio frequencies. A majority of people are probably more familiar with the lower end of the RF spectrum that supports WiFi—2.4GHz and 5GHz.
Devices equipped with special Light Emitting Diodes (LED) can wirelessly send and receive data 100 times faster than WiFi. In a perfect lab environment, LED communication can reach speeds of 224Gbps. The LED bulbs are dipped and dimmed, up and down, at extremely high speeds not visible to the human eye, contrary to the “visible light spectrum” description. Then, another device with a photodetector reads and converts that light into electrical signal.
LiFi’s strengths make it a highly convincing and worthy investment. The technology’s throughput reaches speeds never thought possible, and its wider bands support more users than WiFi.
However, it has weaknesses, too. Due to its higher frequency, its range is shorter and the area it can cover is smaller. Using LiFi would mean using more transmitters, which increases deployment cost. Because VLC system needs light to communicate, it requires near line-of-sight communication. Devices don’t necessarily need to see each other to exchange data because light can bounce off objects but the waves cannot penetrate walls. Although LiFi’s narrow coverage is a disadvantage, it also offers a security benefit. With shorter range, the footprint is easier to control, and wireless hacks can be avoided.
Will LiFi replace WiFi in the future? Probably not. But both technology can supplement each other. LiFi will be able to support: more clients without channels overlapping; higher speeds when necessary; and stronger security when required. It can also be used in electromagnetic sensitive areas where the use of RF could be hazardous.
LiFi, indeed, is a promising technology that will, hopefully, continue to develop and improve wireless communications.
