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Indoor High-Speed LiFi Access

Indoor High-Speed LiFi Access

A LED unit and a USB dongle provide high-speed LiFi network access through visible light and infrared data transfer in downward and upward directions respectively.

Published on 21 December 2017

Indoor High-Speed LiFi Access
A LED unit and a USB dongle provide high-speed LiFi network access through visible light and infrared data transfer in downlink  and uplink directions respectively.

 What is LiFi? 

This form of network access is ensured by bidirectional high-speed LiFi modems. These are built in cooperation with manufacturer Luciom by combining CEA Tech's optics and digital communication know-how.

  • The modem emits information by modulating the intensity of the LED optical power with a 1 - 9 MHz multi-carrier signal (invisible to the eye)
  • The receiving dongle comprises a photodiode that receives the optical signal and converts it to a 30 Mb/s maximum speed digital signal at distances up to 5 m
  • The dongle is plug-&-play, USB auto-supplied and portable
  • The dongle also emits a modulated infrared intensity, return signal to the LED unit


Applications: 

  • Sensitive, secure domains: 

Only portable devices within the light cone can receive the transmitted data unlike those modulating radiofrequency waves (RF), whose range is difficult to control

  • Prevention of RF waves: 
LiFi technology emits no RF data transmission wave and it is therefore not harmful to users

  • Museography and sales areas: 
personalization of visitor experience before, during and after a visit using LED lighting; lighting infrastructure offer new, potentially enhancing services in the same way as square meters of sales area

  • Indoor GPS: 
deployment of new indoor localization services 

  • Healthcare facilities: 
LiFi technology emits no RF data transmission wave and therefore causes no medical equipment interference; it is ideal for usage in healthcare, hospital, retirement and childcare and many other social facilities 



What’s new?

CEA/Luciom's high-speed LiFi modems were the first to provide a bidirectional high-speed access supporting up to 15 users per lamp or LED unit. On the user-side, the low cost-low consumption dongle developed ensures good mobility within the network cell.  The full system provides a transparent IP link to any type of network. Connection or cell changeover times are virtually instantaneous

When dealing with large scale deployment, most of the scenarios are facing intercellular interferences due to the overlapping optical lighting zones of the different LiFi access points. The latest developments at CEA yielded to a custom network layer and software entity called "Global Controller" that collects interference detections, synchronizes the LiFi access points and coordinates them to cancel any intercellular interference. With this, the CEA LiFi solution is the first one to allow on one hand a complete coverage area in large scale deployments, and on the other hand a spatial reuse of the resources which brings a considerable increase of the aggregated network throughput.


Publication: 
 " A High Data Rate LiFi Integrated System with Inter-cell Interference Management  ", 2018 IEEE Wireless Communications and Networking Conference (WCNC).

Illustration: 


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