Breaking Up with Radio Waves: Why LiFi Is a Great Solution for Wireless Networks
Tuesday, May 3rd, 2022
Today, virtually all non-wired Internet connections – including cellular networks – rely on the same radio frequencies we’ve been using since the 1890s. And, as you might expect, those frequencies out of habit are in demand for high-bandwidth, high-security, high-reliability wireless communications.
Fortunately, with an emerging technology called LiFi we can get relief from crowded spectrums. By using light in place of radio waves to provide secure, high-performing wireless connections, LiFi can potentially revolutionize the access layer of the Internet as we know it.
What is Lifi technology?
When I first think of light communication I think of ships in old war movies using a bright spotlight to flash Morse code from ship to ship. We’ve come a long way. By using the same techniques to provide WiFi using radio we can use light to provide a carrier for data at gigabit speed.
LiFi enables data to be encoded and transmitted using the visible, ultraviolet, or infrared light spectrums. This is different to traditional WiFi, which uses radio waves to transmit data between two endpoints.
The way LiFi works is elegantly simple. It basically boils down to turning LiFi backed LED bulbs on and off . The non-disruptive nature of LiFi means that it can be used in settings where radio communications would cause problems due to interference or interception risks – such as battlefields, operating rooms, and factory floors.
Researchers have been working on LiFi technology for more than a decade, and their efforts have finally reached the point that LiFi has become practical to use at scale – and scale is something we know about at Cisco.
An IEEE (Institute of Electrical and Electronics Engineers) task group, the Light Communications Task Group, was formed in 2018 to integrate LiFi into existing wireless Internet standards. Their efforts focus on three main physical layer modes of LiFi operation:
Once fully integrated, the updated standard allows devices with LED emitters to transmit data wirelessly using the same WiFi standard – which means no major protocol changes are required to take advantage of LiFi. A standards-based approach at scale is something Cisco can incubate well.
At the Cisco Innovation Labs we have been incubating and demonstrating LiFi with pureLiFI, a startup and now leader in LiFi, since the company’s inception.
Advantages of Lifi
The potential we’re talking about here is transformative. LiFi offers numerous advantages that solve many of the fundamental limitations of radio-based wireless technology, allowing the Internet to work in places it never has before.
Unlike radio waves, light waves don’t penetrate walls. That means data transmitted over LiFi can be contained in a physical space, reducing the risk of data sniffing by unauthorized third parties.
Similar to radio, LiFi devices can also operate on specific channels – like red, blue and green – which further reduces the chances of data leaks since devices operating on one channel would be isolated from data on another channel.
Both these characteristics make LiFi a great solution for situations that require high data security within a local area. It’s easy to imagine how LiFi could be useful in a boardroom meeting, for example, or as a means of connecting devices within your home, without allowing anyone outside the physical structure to eavesdrop on your Internet communications.
Low interference and Safety
Since the light spectrum is much broader than the radio spectrum, the risk of interference – which occurs when devices try to send different data on the same frequency at the same time – is virtually non-existing with LiFi.
As a result, LiFi is ideal for use cases where the risk of radio interference would otherwise make wireless communications a non-starter.
LiFi is ideal for high security and military use cases where the mere presence of electromagnetic emissions can be used to infer a person’s location or congregation of people.
LiFi has also been be deployed in operating rooms and in factories – both of which are settings where the electromagnetic emissions can cause harm or interference. When safety is a concern light is a benign carrier of information.
Lower interference risks are part of the reason why LiFi is more reliable. The other part of the reason is that LiFi supports higher bandwidth rates than radio waves.
This means LiFi could relegate “dead zones” – meaning areas where radio wave links are too spotty to enable viable communications – a thing of the past. It will also allow a large number of people or devices to share a single LiFi connection without worrying about running out of bandwidth.
No Need for Line of Sight
Typically, people think that light communication means you need a direct line of site to the transmitter. The same reflection techniques used is radio communications are used with LiFi. The IEEE has been working on a standard for Reconfigurable Intelligent Surfaces (RIS) as a way to intentionally redirect radio signals in complicated deployments. Dr Harald Haas (Distinguished Professor of Mobile Communications from the Univeristy of Strathclyde and co-founder of pureLiFi) first demonstrated LiFi technology and is working with a team to use RIS as a hybrid solution for cellular and LiFi.
By using techniques such as wavelength-division multiplexing (WDM) and angular diversity LED transmitters, complex and intentional non-line-of-site coverage can be achieved. I can imagine a deployment where cellular backhaul is used with RIS for rapid deployment of secure edge access. Where the transmission beam can be directed and make use of light’s inherent advantage over eavesdropping threats.
Support for intentional connections
With LiFi, it’s possible to direct data at targeted devices. You can create a wireless network that only works with devices you designate, allowing for an “intentional” approach to network design.
Radio waves don’t offer this type of precision. With radio, your devices transmit data in all directions, and the typical way to restrict which devices can join the network is to use authentication technologies. By using the high drop off of light we can ensure direction and location as part of authentication at the signal level.
Right now, a cumbersome combination of both Bluetooth and WiFi is used for the same purpose. Light can do both in one go.
In-place wireless connections
Given the low bandwidth and high interference risks of radio waves, it’s impractical to use conventional WiFi to connect stationary devices. For that, we still rely on cables or worse use up radio spectrum. If something is wireless and not mobile the precious radio spectrum is wasted on a stationary device.
LiFi, however, changes this calculus. By allowing data to be transmitted at high speeds and between specific devices, LiFi is poised to usher in a future where your monitor or digital sign, for example, can connect to your computer wirelessly.
In addition to untethering us from cables, an approach like this would allow users to reserve radio-based wireless communications for devices that really need them, without clogging up the airwaves with data that can be transmitted via LiFi instead.
LiFi connections can be pinpointed in a way that radio waves simply can’t. This level of precision means you can know exactly what each device is doing over a LiFi connection. This is very important for highly confidential information and/or restricted personnel.
If you are under a cone of light your location is known to centimeter accuracy.
You could track which device is accessing a specific file at a specific location. This is extremely useful when you want to limit access to, or ensure the security of, specific information by allowing access only via a particular area.
In turn, you get more visibility into your network and higher rates of security.
LiFi use case example: The U.S. Army
If you’re still not convinced of LiFi’s transformative power, consider the doors that the technology is opening for the U.S. Army.
Traditional, radio-based communications pose some big problems in military settings. Simply sending data using radio waves can reveal your location to an enemy. In addition, if the enemy can intercept and decrypt the radio waves, any data you transmit can become known. The fact that radio waves can be jammed in order to stifle communications only worsens the issue of using radio for military communications.
LiFi solves all of these problems. Directed, precise LiFi connections enable military actors to send information with a much lower risk of detection or interference. Security is much higher, too, as targeted light waves are much more difficult to intercept.
This is why, to quote Andrew Foreman, U.S. Army Europe & Africa CTO, “LiFi technologies answer the serious issues associated with the RF portion of the spectrum. Due to their low probability of detection, jamming, and intrusion, FSO and LiFi offer an extremely survivable form of communications when in direct conflict with a near-peer adversary.”
Radio waves have served us well for more than a century. But we’ve run into some major walls with regard to the security, reliability and performance of Internet communications that depend on radio waves alone.
That’s why the time is ripe to take full advantage of the light spectrum as a better foundation for WiFi connections. Not only is the necessary hardware – LEDs – cheap and easy to manufacture and install, but as we’ve demonstrated at Cisco light-based and radio-based communications can coexist using standards-based roaming like 802.11r. This means that the transition to LiFi can be made gradually and painlessly.
So, don’t expect your radio-based router or cell phone to disappear tomorrow. But do expect a future where LiFi enables and extends wireless Internet experiences that, until now, have been unimaginable.
If you want more insight on how LiFi will change the internet as we know it, check out the rest of the Tech Blogs.