Since Prof. Harald Haas was talking about “LiFi” and “unlocking the third industrial revolution”, we were kind of curious if this technology would be applicable by us outside of a laboratory environment and within our capabilities.


See his TED talk here

Technology

LiFi beats Wifi

 

Think of a light source being turned on and off in a certain amplitude and a photodiode receiving this pattern and translating it – this is what “LiFi” (Light Fidelity) means in general. It’s not entirely unlike a traditional infrared remote control. Interesting about this technology is, that it could be faster than WiFi due to its higher frequency and broader wave spectrum. And most interesting: One could use an existing LED infrastructure. This is actually not too complicated, so we decided to build a nifty prototype based on that thought.

 

 

 

 

 

 

Our Prototype

 

One of the first things that came to our minds was the lack of communicational diversity in transportation scenarios. Think of the two only ways you have today: horns and flashing. There is no other way to signal another car your wish or concern. No wonder that this causes a lot of misunderstanding.

So we’ve build a headlight and a tail-light, able to communicate. The headlight flashes at high speeds, unnoticeable to the human eye, but distinguishable for the respective tail-light sensor. This allows us to transmit messages via the headlight without affecting its lighting capabilities. Think of an ambulance, able to tell you where to move or a following car at high speed, telling you to move aside when you are inattentive or even telling you the reason for its hurry. The possibilities are vast.

 

 

 

 

Future M2M
Communication Scenarios

 

 

Automotive

The silent horn

Vehicle automation systems rely on various advanced sensing devices and systems. Stereo cameras for example are used not only for ranging but also for several other automotive applications. The built-in image sensors could receive data transmitted from LED traffic light, -signage, -headlights, -tail lights, etc. An LED traffic light could transmit its signal phase and timing. Lane change warning, pre-crash sensing and traffic signal violation warning to avoid accidents might all be viable use cases for visible light communication.

LED tail lights and LED headlights could broadcast internal vehicle information, such as latitude, longitude, speed and even intent, gathered by the car’s navigation system or even the drivers connected schedule to nearby cars and roadside sensors.

 

 

Aviation

Take the Cloud to the Sky

„All mobile devices must be in flight mode“ – why? Because classic radio frequency communication suffers from interference. Mobile phones on aircrafts interfere with the plane’s communication and navigation systems and therefore are prohibited. Integrated light sources in the overhead compartments above every seat might become the access points for mobile devices to connect with the on-board internet. The smartphone’s built-in front camera might pick up the signal from the light source and one could think of a infrared LED for the back channel. This way, every passenger could watch movies, listen to music or just read e-mails while the particular device remains in airplane mode.

 

mkry_vlc_uc3

 

Mobile

Surfing the Streets

Ever had the problem with your roaming costs going through the roof while spending holidays abroad? Why not create the equivalent of a wireless network by turning LED street lamps into wireless access points, effectively letting you move between light sources without losing your connection. While this might work better at night due to the lack of interference it still might work at daylight – assuming the street lamps are turned on during the day as well.

 

mkry_vlc_uc4

 

 

Yay and nay

 


Pros

  • Possible integration in existing LED-infrastructure.
  • Local limitation of data accessibility to a certain position or room.
  • No electromagnetic interference with medical or avionic equipment.
  • Freeing up used electromagnetic spectrum.
  • Worldwide unregulated, available frequencies.
  • Better underwater data transmission capabilities compared to radio frequency.

Cons

  • Limitation to “line of sight” (even though data can be transmitted via reflections, it can’t be transmitted through walls e.g.).
  • Interference with other light sources ( e.g. sunlight) makes it difficult to operate VLC.
  • The light source must be capable of high speed modulation (e.g. Light emitting diodes).
  • The uplink or back-channel mechanism is a problem for bi-directional VLC.
  • No standardization, yet.
  • Handover from one access point to another might be difficult.

So…now what?

 


The broad variety of possibilities and applications drives us to keep on searching for more and even better ideas. Location based services with high accuracy (e.g. museums) user/object tracking, indoor positioning/indoor navigation, emergency guidance, 2nd layer information from advertising billboards – just to name a few. If you are building a LiFi application or just want to share your thoughts with us, just say hello@makery.de

We’d ♥ to hear from you.