Visible Light Communication

It’s been a while since last time, you might be wondering what’s next with communication infrastructure. It’s light this time. It recently has appeared as buzz word Visible Light Communication all across online media channels.

Blue LED

How light can transmit information

Visible light can be guided through an optic fiber which is for instance connected to your home PC. However, when you switch on a light bulb, you immediately see that light can propagate also through free space. The term VLC (Visible Light Communication; sometimes also called Li-Fi) refers to the latter, while FSO (Free Space Communication) refers to invisible light communication.

Information transmission requires a certain amount of spectral bandwidth (Hz). A certain pure color – let’s say blue – has a very narrow bandwidth but poses a high carrier frequency where enough sideband spectrum is available – green is far away. The carrier frequency is modulated by an RF source which contains the information. Modulation causes the light source to change its intensity, either continuously or on/off. The modulation frequency is very high for broadband communication and the flicker not visible by the human eye.

Differences to RF transmission

If light is blocked between transmitter and receiver, there is no communication, except when using a white reflecting surface amplifying indirect light. It therefore cannot be tapped from outside. It doesn’t interfere with RF spectrum and contains much more bandwidth capacity than the RF range. It’s cheap and doesn’t consume much energy.

Visible light has been existing even before life developed (in fact, it was even a prerequisite for life). It is therefore safe to say that VLC is not dangerously interfering with biologic matter. But be advised that if you are encountered by millions of illuminated LED’s, you might not feel at ease with this light smog.

It will not disrupt everything

The VLC market gained traction in 2013 and is forecasted to grow heavily and become a $6b market in 2018. Oh I forgot to mention that even 1782 b.c. there was a VLC market, or haven’t you ever seen a bonfire? There are several commercial industry solutions that allow data rates up to 1 Gbit/s per color. Also, VLC is currently being standardized within IEEE.

Even though technology has become available, even though it can ease the spectrum demand in the RF range and even though LED’s are anyway implemented in electronic devices, there are intrinsic properties that simply prevents from becoming an ubiquitous technology. Weak light sources will heavily rely on a line of sight, which for mobile things is generally not given. Also, daylight means heavy noise and thus limited data rate. It will rather coexist with other transmission technologies like the RF and THz spectrum, even combined with them as triple-stack solution in order to increase bandwidth. However, be assured that indoor and outdoor light sources (household devices, car lights, street lights, …) might exchange information with each other – or with the mobile device you’re carrying with you.

So, don’t switch off the light On Off LED


Fixed Broadband

In my last post, I promised to write about FTTH.

Foundation for a modern game changer

Imagine that the mirror in your bathroom turns on automatically when you step out from the shower. It tells you that your coffee is ready. It prevents you from bad investments by informing you about stock exchange. It recommends you a more adequate tie to your suit. It recommends you anti aging cream because of your additional wrinkles. It recognizes your good mood, tells you that it has increased since last year and advertizes you a city trip. It tells you not to hurry because there is a current traffic jam. It also tells you that 2 employees of your company have been checking frequently a webpage of a certain car make and offers you $100 reward when you advertise the car make during coffee break. There are infinite possibilities about machines recommending actions to humans, the recommendation quality is only a question of the available data, or the amount of explicit and implicit information. So-called recommendation engines rely basically on sensors and human interaction to be able to collect data.

According to a post on netzwoche, there was a discussion during the FTTH Conference 2013 in Zürich about recommendation assistants connected to the network. Futurist Sven Gábor Jánszky stated that we do need intelligent infrastructure as well as the competence to switch off such systems. What we cannot switch off is the amount of sensors measuring temperature, humidity, air pressure, acoustic noise, light, movement, smoke, fire, smell, flavor, electromagnetic field, oxygen, ozone,…Imagine such sensors to be placed in things like smart phones, glasses, clothes, bycicles, cars, wallets, pens, pans, tooth brushes…Imagine the sensors to be equiped with digital signal processing to draw conclusions, and WiFi to send the data immediately to a large datacenter where the data is integrated with data from billions of other sensors. This scenario you might associate chances and threats with is called Internet of Things. Fortunately, it’s all about the capability of human mankind to deal with new technologies in order to survive. This means everybody – especially you – can stop pressing like buttons, evaluating products via apps, deactivating sensor functions, and above all stop outsourcing decisions to machines.

The truly game-changing Internet of Things will rely on (amongst others) fixed broadband. 80% of the mobile traffic is assumed to be caused from indoors. If you cumulate the moderate data rates of your 2 flat screens, 2 notebooks, 3 tablets, 5 smart phones and all the connected things mentioned before, it becomes obvious that the total amount traffic becomes significant and cannot be handled over mobile networks but will be offloaded via your fixed broadband access. The cumulated traffic will become massive and the need for a future proof, ultra broadband fixed network with 1+ Gbit/s becomes clearly visible.

Perceiving ambivalent feelings regarding nationwide FTTH

When I attended the Broadband World Forum 2013 in Amsterdam, I could clearly feel a sense of urgency for FTTH deployments. FTTH Counsil Europe President Karin Ahl reckoned at a podium discussion that the tipping point for FTTH has just been reached. That is, city governments have been continuously educated about the economic importance of broadband access (For instance, the FTTH Counsil Europe assumes a GDP growth of 4.6%). Since they don’t want to be considered as late followers, this has been clearly accelerating investments since the second half of 2012. There was also a moaning, that unfortunately nobody wants to invest and complete FTTH infrastructure at once (nationwide FTTH would cost roughly US$ 100 billion). Indeed, the facts show that the FTTH market penetration in Europe is still in the order of 5% (USA 8%). Assuming a constant growth rate of 15% over the next five years, this means absolut household penetration of 10% in 2019 which is still very low compared to ranking leader South Corea with 58% in 2012. Deutsche Telekom has even stopped to name any goal for 2014 FTTH.

I’d speak of a tipping point only in terms of the perception that some incremental advancement would be needed, far from actions do I consider the actual deployment situation. It’s correct that todays average bandwidth consumption does not require FTTH. But it wouldn’t be foresightful if we didn’t anticipate society’s needs in 2040, since optical fiber is a future-proof medium. Just in times of a slowly growing economy in Europe, it would be advisable to invest anticyclic and therefore spend much more intensive on FTTH.

Get big fast with Fixed Broadband

Broadband access for every citizen cannot be underestimated; I have to emphasize again that the game-changing Internet of Things and also the future economy, will rely on fiber broadband which has a far higher capacity per user than a mobile network has. What the Internet of Things will cause to human mankind and whether the impact will be overwhelmingly positive, is of course another topic which I will dedicate a post. Personally I am absolutely convinced that it will improve the quality of life.

Truly, the future network and its data are hard to control, because it will transform from a lose to a neural network and therefore its complexity will increase dramatically. The crucial action for humans will be to retain control over decision making and not letting it be done by any network or machine. As long as human brains are capable to deal with complexity, one doesn’t have to fear anything. Being said that, the sooner a fixed broadband network is available for the long run, the better. If too late, Europe will find itself in the situation that the rest of the world is wandering off.

Thanks for reading. In the meantime I wish you a successful week and looking forward to your view on FTTH!


Communication Infrastructure

This year, I’ve got a bunch of creativity cards as a Christmas present. The envelope literally says “one always has to do what one is not able to help doing” (man muss immer tun, was man nicht lassen kann). After having noted “Blog erstellen” on the To Do chit, I’ve been sitting in front of my notebook and writing these lines.

Electricity, information theory and semiconductors
It was thousands of years ago when human mankind used bonfires and drums for signalling and sending messages to each other. The higher speed of new communication methods caused information asymmetry which again led to a strategic advantage over the opponent and was therefore crucial to win wars. For example, from the 17th until 19th century, the French introduced fast relay stations based on visible light communication that were mounted on top of buildings and allowed messages to be transmitted over dozens of kilometers in just a few minutes.

Only in 1833 did engineers develop a fully electromechanical-based system to send information over copper wires – the telegraph. This game-changing invention was of utmost meaning for human mankind. The previously understanding of time and space has been reshaped forever. It has become possible to transmit messages over far distances in short times. Just compare a horseman carrying a letter and the speed of light. With Shannon’s mathematical theory of communication in 1948 one was finally able to define upper limits for error-free information transmission. His theoretical conception however doesn’t tell how to approach its limits. The development of the transistor in 1957 served as basis for later digital signal processors that ultimately made it possible to convert Shannon’s theory into praxis. Without the basic technologies electricity, information theory and semiconductors, there wouldn’t be a way to construct modern communication systems like your smart phone or mobile base stations.

Controlling complexity
We write the year 2013 and are surrounded not just by the obvious telephone lines, but also backhauled mobile base stations, virtualized datacenters, communication satellites, street level mobile base stations, broadcast stations, emergency radios, RFIDs, home WLAN and many more. What is distinctive to the ancient communication age is the fact that networks have become much more critical for everybody’s everyday life and they also have become increasingly complex in the order of magnitudes. Therefore it is not just about to connect a transmitter and a receiver; we have to talk about techniques like convergence of fixed and wireless broadband access, distributed antenna systems, heterogeneous networks, macro and small cell backhaul, service provider WiFi, visible light communication, THz communication, machine-to-machine communication, and several more. Additionally there are complex non-technical issues to tackle like fail-safe concerns, the impact from GDP on infrastructure spendings, organisational change management in telco businesses, e-smog, political decisions impacting infrastructure advancements, big data, decisive networks, internet of things and its new biz models, big brother and its new ethic awareness, new social behaviour.

Key findings
Communication infrastructure has never been nice-to-have but a necessity. Today communication infrastructure is absolutely business critical. The future global network – or internet of things – will become a highly complex neural network which requires preceding research. Governments should therefore never stop investing into advanced infrastructure solutions – in the long run it’s less expensive to spend at once than going for short leaps. Given the continuous price decline per transmitted bit (yes, bits can be considered as a currency) and the fading business cases, it becomes obvious that governments, network operators, service providers and private investors need to group together in order to realize infrastructure investments so that no stakeholder suffers from a 12 year ROI of Fiber to the home (FTTH). Speaking of which, FTTH is still growing slowly in europe, so expect my next post to be about fixed broadband.

Have a great day and do what you’re not able to help doing!