The Visible Light Communications Motivation

I have often been asked; what is the motivation for VLC and Optical Wireless Communications?  So, I wish to address the main motivation in this post.

GBI Research - Global Mobile Data Usage Taken per Month on an Average (Eb/Month)

Figure 1 - Global Mobile Data Usage Taken per Month on an Average (Eb/Month), Source: GBI Research

The compound annual growth rate (CAGR) of mobile data usage per month for the next four years is estimated to be around 80% as can be determined from Figure 1.  Assuming no extra additional radio frequency spectrum, this would mean that gains on spectrum efficiency have to be increased in the same manner through new technology, but it has been reported that the spectrum efficiency gains of cellular systems are slowing. In fact they are saturating, as can be seen from Figure 2.  One solution to the emerging problem is the release of additional radio frequency spectrum for mobile communications, but unfortunately most of spectrum of interest (in the 1 GHz – 10 GHz region) is already in use, and identifying new radio frequency spectrum to keep up with exploding wireless data demand is impossible.

Qualcomm wireless spectral efficiency gains

Figure 2 - Spectral Efficiency Gains are Slowing, Source: Qualcomm

As a result of the problem I have highlighted, the Federal Communications Commission (FCC) has issued warning and has been speaking about a “looming spectrum crises”. This warning is underpinned by the recent report of GBI research in which they have shown a significant gap between required network capacity and the predicted available capacity. This gap is shown in Figure 3 where the forecast traffic per device is shown as well as the forecast available network traffic per device. If the expected trends prove to be true, we will see a shortfall of network capacity of about 97% in the year 2014.  A spectrum crisis would be unavoidable.

Capacity per Wireless Device and Forecast Traffic per Device

Figure 3 - Capacity per Device and Forecast Traffic per Device for a 3G Operator, Source GBI Research

I believe that it is the right time now to develop radically new solutions for future, post-LTE wireless networks. The approach taken is to consider an entirely different part of the electromagnetic spectrum – the infrared and visible light spectrum – that is largely unused for communication and more than 10,000 larger than the entire microwave spectrum.

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VLC in toys next Christmas?

Visible light communications technology could be in toy shops as early as next Christmas!

My previous top 10 VLC applications post has been well cited but did not include toys as an application.  If it had been my top 11, then toys might have been there and on reflection it probably warrants a top 10 position as I can see the application being one of the first to hit the shops.  With just one month to go until Christmas 2011, I know we won’t be seeing anything this Christmas but what about Christmas 2012?

Before answering the question, let us consider why VLC should be used in toys?

VLC in LED toys by Christmas 2012Toys continue to grow in sophistication and many now have radio control and a multitude of LED flashing lights.  If we therefore consider that the LED lights can be used to transmit data over a short range as an alternative to radio, then all that is required is a photo-detector.  However, there is a clever trick that can be played to avoid increasing the bill of materials. It is actually possible to re-use an LED as a photodetector device.  Here is the technical bit: when a voltage is applied across an LED in the “correct” direction (called forward biased) it will emit light, when the voltage is applied in the opposite “wrong” direction across an LED (called reverse biased) then the current that will flow through that LED becomes proportional to the light that falls on it.  In other words, a reverse biased LED becomes a photodetector.  With a simple circuit it is easy to switch between these two modes.  More detailed technical information can be found in an excellent MERL whitepaper from 2003.

So the answer to the why question is that all of the components required for short range communications using VLC between toys already exits.  This can save the cost of adding radio circuits into toys and would allow lower cost electronic toys to have communications capability, and it is safe too.  It just requires a little engineering ingenuity to unlock this functionality.

So my prediction – VLC in toys by Christmas 2012!

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VLC wins at IBM SmartCamp

Visible Light Communications wins the People’s Choice at IBM SmartCamp

IBM SmartCamp LondonIBM have been at the forefront of technical innovation for over 100 years, so they do know a thing about backing the right technology.  They also know that not all of the great ideas will come from within their own ranks, so they run a series of events around the World called SmartCamp.  SmartCamp is an exclusive event aimed at identifying early stage entrepreneurs who are developing business ventures that align with IBM’s Smarter Planet vision.

The IBM SmartCamp London event on 17th November was the climax to a rapid but multi-stage selection process.  Five finalists were eventually lined up at the event in London, including VLC Ltd. I am therefore delighted to report that VLC won the live on-line vote by a large majority and were crowned “Peoples Choice”.  Clearly the voting public saw the massive opportunities and recognised that this technology can change the world and create a Smarter Planet.

I would personally like to thank you if you voted for VLC, your vote did count.

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VLC at IBM SmartCamp London

VLC for a Smarter Planet

IBM SmartCamp LondonVLC Ltd has been selected as one of five finalists at the IBM SmartCamp. You can watch the one minute pitch and please support us by clicking “Like”.  We are delighted that IBM recognise how visible light communications fits with their Smarter Planet vision.  You can come and support us at the final at 2.30pm on 17th November at IBM South Bank, London.  The event has been timed to coincides with Global Entrepreneurship Week.

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Light at the end of the Ethernet

Where does PoE fit with VLC?

Cat5 cable for PoE and VLCI have previously talked about Ethernet over power, also known as power line communications (PLC) and the fact that this is a complementary technology to VLC since it allows the communications backhaul to be carried over the existing lighting power circuits.  Now I want to consider Power over Ethernet (PoE), a technology that has been around for a while but is growing in popularity.  Ethernet cables, such as CAT5, are clearly designed to carry data, but there are PoE standards designed to allow them also to carry power.  The idea being that low power Ethernet connected devices, such as VoIP phones, networked cameras etc. can have just a single connector and no additional power adapter is required.

PoE comes in a number of flavours.  There are two IEEE standards; 802.3af and 802.3at which both use a spare pair of conductors to carry the power.  The more common af standard can provide up to 15W of d.c. power rated at 44V, 350mA.  The more recent at standard known as PoE+ provides up to 30W.  There are a number of non-standard variants and Cisco’s recently announced universal PoE variant (UPOE) can carry up to 60W of power using two pairs of cables from a CAT5e or CAT6 cable.

So why not use PoE to power high efficiency LED lighting installations since now the power, voltage and current parameters are well matched to this application.  It seems to me, not just feasible that PoE infrastructure could be utilised for lighting, control and communications within a building, but it also seems very sensible.  We have ourselves demonstrated high speed data communications transmitted from an IP connected light bulb.  A number of companies including NXP and Color Kinetics have demonstrated the control of lighting via PoE, so we just need to add lighting power to this mix.  Of course there are practical issues such as the length of the cable runs and the voltage drop over this distance, but these are simply constraints and not show stoppers.

Cisco PoE switch A large Ethernet switch with UPOE could be enough to power a whole office in the not too distant future.  With up to 60 W per connection the lights can be centrally powered and controlled, VLC can provide high speed wireless communications and the same infrastructure also supplies all of the wired communications and energy efficient desk top power too.  This is potentially a great fully integrated technology, well great until the fuse blows – so better add battery back-up to the standard!

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Li-Fi Consortium is Launched

In a press release issued yesterday the new Li-Fi Consortium ™ was launched with the aim of promoting Optical Wireless Communications.

The Consortium’s stated mission is: “to promote new high-speed optical wireless usage models both indoors and outdoors.  The Li-Fi Consortium provides resources for OEM and ODM developers to create exciting new products.  With the emergence of high-speed cable connections like Thunderbolt and USB 3.0, the stage is set for a wireless equivalent. While Wi-Fi is very popular for pervasive 100+ Mbit/s service, multi-Gigabit short-range optical wireless interconnects provide an alternative to the proposed WiGig Gigabit RF solution.”

The Li-Fi Consortium is promoted as an industry group open to any company focused on the commercial development of optical wireless communication (OWC) technology.  Unlike VLC, OWC includes infra-red (and in theory UV) as well as visible light and so the community is potentially quite diverse. The founding members are perhaps an early indicator of the shape of the Li-Fi Consortium.  These members are: Fraunhofer IPMS, Germany, IBSENtelecom, Norway, Supreme Architecture, Israel/USA and TriLumina, USA.Li-Fi Consortium FoundersI must admit to being unaware of the formation of this group until yesterday so I am keen to learn more and share this information with the VLC community.  Perhaps I can get one of their founders to provide me a suitable post for this blog.  So far I can only see positives in the launch of the Li-Fi Consortium since it wishes to establish relationships with other organisations “which can help create a mature industry environment for implementers.”

What is Li-Fi?

As far as I am aware the term Li-Fi (short for Light Fidelity) was coined by Harald Haas in his TED Global talk in July this year as a way to convey the similarity between Wi-Fi and light bulbs transmitting data*.  Consequently the term was reported in many articles and seems to be rapidly entering common parlance to describe visible light communications or in this case optical wireless communication.  Having now been adopted by the Li-Fi Consortium I feel the term has now been claimed by the optical wireless industry to describe wireless data access points using light (visible or otherwise).

The Oxford English Dictionary (OED) describes Wi-Fi as: Wi-Fi (abbreviation); Wireless Fidelity, a group of technical standards enabling the transmission of data over wireless networks. It might be a while before Li-Fi enters the OED but perhaps it has already earned itself a Wikipedia entry.

* Luxim have used LIFI as the name of a specialist lamp but this had no data capabilities.

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Wireless Spectrum Shortage Solution

I have just purchased the Global Business Intelligence report on Visible Light Communication which is the first commercial report on this topic.  It is called “Visible Light Communication (VLC) – A Potential Solution to the Global Wireless Spectrum Shortage” and has 77 pages covering the technology in general, the market dynamics and the key players.  The table of contents is listed here.

Radio spectrum is at full capacityAs suggested in the title VLC is presented as a solution to the shortage of radio spectrum.  This is a view I personally share and is the primary reason I became excited by this technology a couple of years ago. I was therefore very eager to see what was in the report.

The report begins with an overview of the technology and it’s benefits.  An emphasis has been put on illustrating the extent of the radio spectrum shortage problem relative to the exponentially growing demand for wireless data.  A section called VLC Technology Market Segments deals with the application areas (and also some complimentary technologies).  The middle sections make comparisons with infra-red technology, a short geographical market analysis and forecast of the markets for the various VLC components.  The report concludes with sections containing data on VLC research around the world and on the key players.

I think the report is excellent in highlighting the need for an alternative to radio spectrum and the opportunity created by LED lighting.  The market analysis sections I thought would have benefited from a more quantitative approach and a little more analysis.  The final sections on VLC research and key companies are extremely useful. To my knowledge no significant VLC research centre has been omitted.  In terms of the companies, only LVX System actually have a commercial VLC system in place to date so they are dealt with first.  The other companies are: NEC, Rise, Gallium Lighting, Sobal, Outstanding Technology, Casio, and Intel.  These are mostly established companies with active interests in VLC.  In my opinion I would also have included Samsung, Boeing, Renesas, InterDigital and recently incorporated ByteLight in that group for completeness.

VLC a solution to a global problem.Overall a very useful report on Visible Light Communication and one that acknowledges the emergence of a VLC industry.  I could recommend this report to anyone with a commercial interest in this technology.  For the next VLC report I would like to see market analysis which actually quantifies the value of the VLC segments.  Maybe I need to do that analysis and produce the report myself! Pre-orders anyone?

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VLC pioneer in running for World Technology Award

Prof Harald Haas is in the shortlist of finalists for a prestigious World Technology Award recognising his work on Visible Light Communication.

World Technology Summit & Awards 2011

Prof Harald HaasThe winners will be announced from the stage of the United Nations at the World Technology Awards ceremony in New York next month. These awards are presented to individuals and companies who are, in the opinion of the judging panel, doing the innovative work of “the greatest likely long-term significance” in their fields. They are those creating the 21st century!

In the individual Communications Technology category Harald is up against some stiff competition from six other individuals from Bell Labs, Facebook, Yahoo and other prestigious companies. He is the only academic in this category and I would like to wish him all the best in New York.

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VLC at LuxLive

LuxLive 2011 featuring VLCLuxLive in London 9-10 November.

The Earls Court Exhibition Centre in London will host the LuxLive lighting industry event on 9th & 10th November.  The exhibition is combined with a conference programme including TechTheatre dedicated to new technologies in the lighting industry.

I was excited to hear that Jim Crowcroft of TCP will be talking about their internet-connected light bulbs which can be controlled by a smart phone.  This technology has huge synergies with visible light communication.  Jim’s keynote talk on the Wednesday morning immediately precedes my own presentation on VLC so it should be possible to illustrate this connection to the audience.A smart phone used to control domestic lighting via the Internet

In my own talk called “Luminaires – the New Wi-Fi” I will explain, or even demonstrate, how LED light fixtures can be used to transmit high-speed data.  I aim to show why visible light communication represents a major opportunity for the lighting industry. I will also highlight what we are doing to help smooth the path towards adoption of VLC by the professional lighting community.

I plan to be at the event on both days and hope to be able to give live demonstrations of VLC in a smart lighting context.  If you are visiting LuxLive and would like to talk with me, please drop me an email in advance (see contacts page) and I will try to arrange this into my schedule.

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D-Light project hits target

The D-Light project at the University of Edinburgh has been active for close to two years and has made a number of advances in the field of visible light communication.  Most notable is the work on special modulation methods and encoding schemes enabling large data rates to be achieved from commercial off-the-shelf components.  As a member of this team, I thought I might take the opportunity to blow our trumpet a little about our recent achievements.

When the D-Light project began in January of 2010, it had two primary objectives.  The first was technical and the second was commercial.  These objectives were to be achieved within two years, i.e. by the end of December 2011.

D-Light Technical Objective:

To achieve a minimum of 100Mbit/s data rate from a standard low-cost LED light bulb and this would be achieved under normal lighting conditions.  The test distances would be 1-4m and the error rates would be better than one error in 10,000 bits (so that the errors can be corrected). The signal processing was also to be done in real-time.

It is accepted that it would have been possible to achieve considerably better headline data rates with special LEDs under controlled lighting and by allowing greater error rates over shorter distances.  It is also much simpler if the signal processing is done off-line rather than in real-time. However, the reason for the practical constraints will become obvious when the commercial objective is explained.

D-Light Commercial Objective:

To create a spin-out company!

To create a viable spin-out company requires the development of products (or services) that work in real operating conditions, rather than controlled lab conditions.  This is the reason that the technical objective had a very practical, as opposed to academic, focus.

Technical Achievements

Popoola, Haas, Afgani

The D-Light technical team. From left to right; Dr Wasiu Popoola, Prof Harald Haas & Dr Mostafa Afgani. Copyright (c) Peter Tuffy, The University of Edinburgh.

The D-Light project team are pleased to announce that the main technical objective has been achieved ahead of schedule. 102.5Mbit/s has recently been measured in normal lighting conditions (with sunlight and artificial lighting). This was achieved using an off-the-shelf 18 watt Osram Ostar white LED lamp. The desired test distance was achieved with measured error rates of better than 1:10,000 and all of the processing is being done in real-time. Having achieved the project’s primary technical objective with more than 3 months remaining we can expect further improvements before the project concludes. The projects technical team are to be congratulated on this achievement.

The Spin-out

The viability of the spin-out company is not so much about the technology itself, it is about what can be delivered to the customer in the near-term, i.e. VLC applications they are willing to pay for.  We are now focussed on short-term VLC revenue opportunities, the long-term opportunities seem massive but there is only a long-term where there is short-term viability.  The great news is that the D-Light spin-out seed investment round is likely to be oversubscribed based on the interest expressed at this stage and so we might expand the goals of our seed phase.  Potential investors for this or future rounds can contact me at via the contact page.

So it now seems certain that the spin-out will happen; the team is motivated, the University want this to happen and the investors are keen. We are already certain that we can raise the minimum requirement in the seed round.  The primary commercial objective looks certain to be achieved.

Mission Accomplished

In term of the D-Light project goals, it looks certain that our mission will be fully accomplished.  Of course as any Entrepreneur will tell you – that was the easy bit, now the real hard work begins!

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