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“Li-Fi”: wireless communications through light August 24, 2011

Posted by Brandon in Technology Forum - the Art.
Tags: , , , ,

Imagine if you could access the internet by connecting to your desk lamp or a street light?  Harald Haas is developing the technology.

Last month, Dr. Haas gave a “TED talk” to audiences in the UK to present this technology and discuss its implications.  TED talks are presented by TED conferences LLC, a nonprofit established in 1984 devoted to spreading ideas from innovators in technology, entertainment and design [TED]. Speakers are invited to present at two annual conferences where attendance fees are charged, but then the videos of the event are copyrighted, released and shared under a license from creative commons.  The license, CC BY-NC-ND v. 3.0, permits the right to copy, distribute and transmit the video of TED presentations so long as the authors are attributed in the work and the video is not modified or used for commercial purposes.  Accordingly, by attributing TED conferences LLC and Harald Haas as the original source of these materials, I may share the contents of the video in which the following idea was presented.

D-Light Technology

Harald Haas, a professor at Edinburgh University and inventor of numerous patents, has developed a technology he calls D-Light, which can access the internet wirelessly using light instead of radio frequency (“RF”) waves.  He considers wireless communications a type of utility, much like water or electricity.  However, like other utilities, wireless communications have problems which limit the scope and usefulness of the technology.

Namely, Dr. Haas identifies four problems with wireless communications: capacity, efficiency, availability and security.  Capacity issues arise with RF because of bandwidth, efficiency issues with the majority of energy going to cooling base stations, lack of availability in RF reception, and security issues with the potential of RF signals to be intercepted and transmission through walls.  The use of light to replace RF solves all of these issues, explains Dr. Haas.

The D-Light technology itself comes from a microchip which is inserted into an existed LED lightbulb.  The technology uses a “mathematical trick” called OFDM, or orthogonal frequency division multiplexing, which quickly turns the LED lightbulb on and off at a rate indistinguishable with the human eye.  The OFDM is a special modulation of the LED to enable the light source to transmit data.  Ordinary RF waves send binary code to receivers through individuals lines, but OFDM technology in an LED bulb sends thousands of streams of binaries in parallel to other devices in a much wider spectrum, increasing processing and bandwidth.  In the video, Dr. Haas demonstrates the transmission of a high definition video through a desk lamp bulb transmitter.

Certainly, the implications of a successful trial of this technology is profound.  Lights are available anywhere, as Dr. Haas notes, from hospitals to aircraft to smartphones and deep-sea remote machines.  Dr. Haas addresses concerns that multiple light sources can distort the reception, and dismisses the possibility.  He says that the D-Light technology addresses all of the four concerns with wireless communication systems.  Regarding capacity and availability, light bulbs are abundant, nearly 14 billion worldwide by his estimates with capacity 10,000x that of RF, so an infrastructure already exists.  As lights are on the scale of the electromagnetic spectrum between infra-red and ultra-violet, the technology is safe and efficient.  Finally from a security standpoint, Dr. Haas says that light cannot easily move through walls, which limits access.  All that we need to do is replace incandescent lightbulbs with the semiconductor LED bulbs.

Patent Concerns

One of the first questions any investor, or skeptic of the technology, will ask is whether Dr. Haas has a patent.  It appears he did.  However, the patent application that he filed for this technology, which he calls “optical free space data transmission”, was assigned to Airbus in Germany.  This is reflected in all of his patent applications for the technology in the US, the EU, Japan, China and a few other nations.

The patent itself, US patent application number 20110069958, is described in the abstract as an invention that relates to “an aircraft data communication system as well as an aircraft comprising such a data communication system, in particular a wireless optical communication system inside an aircraft cabin and outside for aircraft services”.  While this wouldn’t appear at first glance to include the use of ‘D-Light’ technology outside of an aircraft, the patent laws are notoriously vague and patent claims in the past have been interpreted to extend well beyond the original embodiment.  One compelling critique of the US patent system argued that inventors can hide claims, and even if there was access to those claims, they are hard to interpret. Moreover the authors argue, even the interpretation of a claim could change over time, which is further diluted by the fact that clear unambiguous claims are still very expensive to research and locate.  See James Bessen and Michael J. Meurer, Patent Failure: How Judges, Bureaucrats, and Lawyers Put Innovators at Risk, Princeton Univ. Press (2009).  Therefore, the possibility arises that Airbus could sue and enjoin Dr. Haas from further developing this technology.

Would this be an unlikely event?  Dr. Haas has two other patent applications in 2011 that could be similar to his D-Light technology; a “method and apparatus for scheduling information” (Patent application # 20110143799), and a “mobile and base station transceiver apparatus for communicating (Patent application # 20110003611).  Please feel free to leave general or specific comments below.


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