How Li-Fi will impact access networks and IoT

How Li-Fi will impact access networks and IoT

Wireless transmission of information has been around for centuries. We are all used to connecting our smartphones, tablets and laptops over radio protocols such as Wi-Fi, 4G and Bluetooth. Over the past years, solutions for home automation, connected cars, smart cities and other Internet of Things (IoT) areas have raised awareness for other types of radio standards like Zigbee, LoRaWAN, NB-IoT and Z-wave.

The common denominator for these types of communication is that it is carried out on a very small chunk of the popular Radio Frequency (RF) spectrum which, in turn, is a fraction of the overall electromagnetic spectrum that spans not only RF but also various types of light, gamma rays and x-rays (see the figure below, borrowed from .

Li-Fi is a technology where light waves (rather than RF waves) are used as the communication medium. This is nothing new. In fact, visible light was used to carry information in some of the earliest semaphore and smoke signal wireless systems in history. Camera based IoT devices are often using the same spectrum.

In this article, we take a look at how Li-Fi works, its pros and cons, how likely it is that you have to swap your Wi-Fi router to LEDs in a couple of years and which applications/IoT areas where we expect to see a lot of Li-Fi in a not too distant future.

What is VLC, OWC and Li-Fi?

Optical Wireless Communication (OWC) refers to wireless communication over infrared (IR) light, visible light (VLC) or ultraviolet (UV) light. Applications using this spectrum today range from remote controls, video camera IoT solutions, tracking systems in healthcare, access networks and laser backhaul links. Li-Fi today normally refers to data being transmitted over visible light.

How does Li-Fi work?

Just as RF based wireless solutions like 4G, Wi-Fi, 5G and Bluetooth, Li-Fi uses transmitters and receivers to communicate. The transmitter typically consists of Light Emitting Diodes (LEDs) of the same type you buy in your local store. It could also be the flash on your mobile phone, a LED display, the spotlight of a car, a traffic light or something else that emits light.

Data is modulated (by single or multi carrier techniques) by adjusting the brightness of the LED at a very rapid pace that is not noticeable by the human eye. With visible light, it is even possible to do this in a room that the human eye would experience as ”dark”. The receiver (which could be the camera on your phone) can register the differences in brightness and decode the transmitted signal even in full daylight. The figure below shows Li-Fi demonstrated from regular street lights in Denmark. The receiver in this demo system is shown in the bottom left corner of the figure.

Which benefits do Li-Fi bring over RF based wireless communication technologies?

Li-Fi brings some interesting things to the table:

  1. Massive throughput. Almost 10 Gbps peak rates have been demonstrated from a single light source.
  2. Much simpler and cheaper transmitters and receivers. Modulating light intensity does not require any radio front ends with amplifiers, filters and antennas. Less patent royalties have to be paid to chipset makers. As the result, Li-Fi is expected to be 10x cheaper than Wi-Fi.
  3. Extremely low energy consumption. This brings a lot of benefits to body-near devices like AR/VR glasses, watches, bracelets and badges where the battery lifetime is crucial for the end user experience.
  4. High security. Only if you can see the light you can ”hear” the communication.
  5. No RF pollution. As a Li-Fi transceiver does not emit RF waves, it does not generate Intermodulation Products, spurious emissions, noise or interference to RF equipment.
  6. Unlike for RF base stations and access points, you never have to find sites for LEDs. Those already exist.

What are the challenges for Li-Fi?

Li-Fi obviously requires the receiver to ”see” the light sent by the transmitter. It does not have to be line of sight, but the light has to be bright enough That is not the case with RF communication which often can traverse walls and other obstacles. The main problem for laser links, remote controls and Li-Fi is therefore that the signal path could be blocked by clothes, fog, snow or something else.

Another challenge is that you need backhaul to the LED armature. Albeit that could be a wireless link (over RF or light), a typical installation in an enterprise building or a hospital would require each armature to be backhauled by an Ethernet link (LAN cable or optical fiber). No problem in newer buildings, but it could be a retro-fit challenge.

Which are the typical application areas for Li-Fi?

Cheap transceivers, low power consumption, massive capacity and high security means Li-Fi will be extremely useful in certain areas. Examples:

  • AR/VR glasses, watches and other gadgets that are not placed in a pocket and where battery lifetime is crucial for the user experience.
  • Internet of Things applications. Here, Li-Fi can be an in-room carrier of data from battery-powered devices to a sensor platform placed in the ceiling, it can be used for tracking of gadgets in a hospital or factory, it can be used for indoor wayfinding and on-boarding of devices in a smart office. The fact that you easily can communicate with a LED display opens doors.
  • Access networks in sensitive environments where security or RF pollution is unwanted. Airplanes, nuclear plants and hospitals are often mentioned.

Will Li-Fi replace Wi-Fi?

We need to divide Wi-Fi into two areas to be able to answer that:

  1. Traditional Wi-Fi access points operating at 2.4GHz and 5GHz. The same type that you have at home and in your office today. These were once created in order for average Joe to be able to very easily cover an apartment or mid-sized American house from the point where the cable modem entered the building. Doing the same with Li-Fi would require cables to every room and an army of electricians.
  2. Then we have the new type of Wi-Fi standards operating at 60GHz. We often refer to this as ”WiGig”, and it differs from traditional Wi-Fi in two ways:
    1. Enormous bandwidth.
    2. The higher frequency makes it very hard for signals to penetrate walls. Good as you will not hear your neighbors network, but it also means you need one WiGig AP per room where you need capacity.

Since WiGig is created for short-range, high capacity, in-room use cases, it is much more prone to competition from Li-Fi. If we compare the two technologies, we expect Li-Fi to come out both cheaper and a lot more flexible (pre-integrated in cameras, LED screens etc.) over time.

Li-Fi is an extremely potential technology that we expect a lot from in the coming years. We will follow this space closely.

Main image source:

Ten things you didn’t know about the Internet of Things

Ten things you didn’t know about the Internet of Things

1. “50 billion connected devices” has already happened

Some say there will be 50 billion connected devices in 2025. It has already happened. Everything from cars and Barilla pasta to Nespresso capsules and Gillette razors are already connected and powered by IoT. Uber’s entire business model is built on an IoT platform. Your phone is probably part of tens or hundreds of IoT business models depending on how many apps you have installed.

2. Most devices will never be connected to the Internet

Unlike the previous “versions” of the Internet (content/people/mobile) that have been driven by standardization and certification, IoT is completely application driven. This has resulted in countless jungles of proprietary wireless techniques, protocols, platforms and applications that are tailored for various use cases but cannot talk to each other. Device communication outside your own IoT network is rare which is fine as there is generally no value in connecting your dog to a meeting room at the office or a fan system in a building to a car. IoT generally means Intranets of Things.

3. IoT Business Intelligence never gets better than the data you collect

Ok, you knew this already but it still needs to be highlighted. There are air quality sensors not capable of measuring data at a relevant resolution and energy meters that sit inside metal boxes in people’s basements without ability to get a wireless signal. If you cheat on radio front end, antenna design, network design, security or sensor quality it will bite back. Advice: Do not cheat.

4. You might already have access to the data you need

Example: A municipality could dig down hundreds of thousands of on-street parking sensors all over a city, or they could invest the money in a mobile payment platform like EasyPark that can provide the parking status via an API. No sensors, no hassle, just data, and at the same time they get rid of the parking ticket payment machines. The same applies for buildings, healthcare and a lot of other areas where sensor technology already exist. Before you roll out sensors or build a network, carefully consider if there is a smarter way of collecting the data.

5. IoT might be the next millennium bug

Pretty much every device is advertised with a maximum battery life time of ten years, and a lot of IoT systems are sold without lifecycle management support. Will all sensors we roll out today have been replaced by something else in ten years’ time or are we creating a new massive “millennium” bug when everything stops working in 2027? Many wireless networks will be gone ten years from now and sensor technology evolves all the time. It does not hurt to have a long-term plan.

6. A lot of sensors will soon be replaced by something else

The exponential technical evolution results in new technology reaching a lot of users faster than before, but also that technology gets outdated much quicker. VHS, CD and mp3 are good examples. Cameras and image recognition will replace a lot of sensor technology sooner than we think. As mentioned above, parking sensors can often be replaced by a software API. There are other concepts too, like synthetic sensors that potentially can replace a lot of legacy in-home sensors and at the same time increase security. Augmented Reality will replace many indoor positioning services where the aim is to find something. And on it goes.

7. The location of connected devices and sensors is more important than you expect

At a first glance, knowing the exact position/location of a device or sensor is only important if you are dealing with tracking/positioning of objects. However, if you automatically get the position of something it simplifies inventory, support and troubleshooting, and this can prove to be worth a lot for the TCO. Consider an activity based office where sensors with 5-10 years battery lifetime are spread out under tables, on trash bins and in meeting rooms. Will you refurnish, re-organize or move to another office during the coming five-ten years? Probably, and unless you are planning to arrange a massive “sensor hunt” for your staff, make sure you take measures. You get similar benefits when streetlights, parking sensors, water meters and other things report their position automatically.

8. IoT is about ecosystems. Be an attractive partner.

There are a lot of companies out there trying to figure out how they should be relevant in the IoT space. Many of them create own platforms, boxed solutions or develop own and very proprietary protocols. Most of them reinvent the wheel. A better approach is to stick to what they do best and refine that even further while joining ecosystems where their piece of the puzzle fits. Example: If your core business is to analyze a certain type of medical disease, do not employ backend coders to build a platform for this. Someone else has already spent 30 000 man hours to productify something that works. Instead, employ doctors and spend time with patients to build value in your algorithms.

9. Small scale is not the same as large scale

During 2018, tons of small-scale IoT Proof of Concepts (POCs) have been carried out all over the world. In many cases, some Low Power Wide Area Network (LPWAN) technology such as LoRaWAN has been used as the bearer of sensor data. Many of these POCs will scale up during 2019 and onwards, and that is when new types of issues will arise. The LoRaWAN ecosystem is scattered. Narrowband IoT comes with battery constrains. The 868MHz frequency band is very small without any guaranteed sustainable future, especially in larger cities. Provisioning of devices, distribution of security keys and certificates, platforms and their price plans, quality of sensors, precision in sensor measurements and much more will be very different when scaled up.

10. Your biggest IoT challenge is not technical

The evolution curve of technology has surpassed the pace of human adaptation rate and the result is that legacy processes and procurement processes, laws, politics and poor business impact analysis block innovation. We all see this daily when we buy new technology that comes with a massive engine under the hood while the user experience still is an old bicycle. A tender process (from RFI to purchase order) can take several years, and when it is time to buy in to something it is already outdated technology. To get things going, do not focus on technology but business operations, people, needs and user experience and set measurable goals for your IoT projects.