Li-Fi, which is short for “light fidelity,” is a wireless technology that uses optical light to transmit information (as opposed to Wi-Fi, which also transmits light, but at much lower radio frequencies.) Proponents claim that Li-Fi could deliver more reliable data transmission at faster rates than Wi-Fi.
Since Harald Haas, a professor at the University of Edinburgh, popularized the term Li-Fi in 2011, companies including the former Philips Lighting—now Signify—and Haas’s own pureLiFi have tried to commercialize the technology. It’s been tested in offices, schools, and even airplanes, but has so far struggled to gain widespread adoption.
Now, Li-Fi has completed its first tests in a hospital—a place where its reliability and speed may prove particularly valuable. A team of researchers from the Fraunhofer Heinrich-Hertz Institute (HHI) in Berlin and the Czech Technical University (CTU) in Prague published results from a demonstration, which they announced at the recent Optical Networking and Communication Conference in San Diego. Their new study lays the groundwork for possibly someday using Li-Fi in a medical setting.
The researchers set up multiple Li-Fi transmitters and receivers in a neurosurgery operating room at Motol University Hospital in Prague. In a series of tests, the Li-Fi system managed to transfer data quickly and without complete signal loss. They achieved data rates of up to 600 megabits per second—better than most Wi-Fi connections and cellular networks
Prior to this work, “there was no experimental study happening in a medical scenario for Li-Fi,” says Sreelal Maravanchery Mana, a lead author and researcher at HHI. “This is the first time we are doing realistic measurements [in a medical environment].”
In a basic Li-Fi setup, data is sent to a transmitter—an LED—which converts it into light that pulses far too fast for the human eye to see. A receiver detects the pattern of light pulses from the LED and converts that pulse pattern back into data. Because Li-Fi uses higher-frequency light than Wi-Fi does, it could, in theory, have a higher bandwidth and therefore transmit data more quickly.
Wi-Fi has been critical to managing the number of smart devices that now populate hospitals and operating rooms. Any technology that limits wires, which can pose a safety hazard in hospitals, is welcomed. But devices that use Wi-Fi can interfere with one another, causing connection loss. “Wireless devices which are transferring medical data must be highly reliable,” says Heikki Karvonen, a researcher at the University of Oulu in Finland, who was not involved with the study. It’s important, Karvonen says, that the devices “coexist” with one another.
Not everyone is convinced that this crowding is a major problem for hospitals: one study simply recommends that smartphones running on Wi-Fi networks be kept an arm's length away from medical devices using Wi-Fi to prevent interference.
And Li-Fi isn’t perfect. While it doesn’t face interference from other medical devices, it can still be interrupted. Unlike Wi-Fi’s radio frequencies, which can pass through walls, optical light is easily blocked by humans or objects. To get around this issue, the HHI researchers used four transmitters and six receivers around the operating room, for a total of 24 channels between transmitters and receivers.
“Even if 23 of those channels are blocked, you still have one and you can have a very robust communication,” says Dominic Schulz, a researcher at HHI. During an operation, it’s possible doctors or nurses could block some of the links between transmitters and receivers by walking between them. The team plans to continue testing different Li-Fi setups in hospitals, and eventually use the technology to transmit data to medical devices being used during an actual surgery.
Currently, the U.S. Food and Drug Administration (FDA) has no official position on Li-Fi. “When planning to use Li-Fi—or any other wireless technology—in medical devices, care should be taken to match the device wireless functions with the wireless technology’s capabilities and expected performance,” says Mohamad Omar Al Kalaa, an electrical engineer at the FDA.
Whether Li-Fi’s LED transmitters and receivers become a fixture in hospitals remains, quite literally, to be seen.