Category: Uncategorized

A few weeks ago I asked the question here if anyone knew what the 4 dots in the GSM logo actually stood for. A few people contacted me with good suggestions what the dots could stand for, which was quite entertaining, but nobody really knew. On the more serious side, however, a few people gave me interesting hints that finally led me to the answer:

On gsm-history.org , a website of Friedhelm Hillebrand & Partners, and article is published that was written Yngve Zetterstrom. Yngve's been the rapporteur of the Maketing and Planning (MP) group of the MoU (Memorandum of Understanding group, later to become the GSM Association (GSMA)) in 1989, the year in which the logo was created. The article contains intersting background information on how the logo was created but it did not contain any details on the 4 dots. After some further digging I found Yngve on Linkedin and contacted him. And here's what he had to say to solve the mystery:

"[The dots symbolize] three [clients] in the home network and one roaming client."

There you go, an answer from the prime source!

It might be a surprising answer but from a 1980's point of view it makes perfect sense to put an abstract representation for the GSM roaming capabilities into the logo. In the 1980's, Europe's telecommunication systems were well protected national monopolies and there was no interoperability of wireless systems beyond country borders, save for an exception in the Nordic countries, who had deployed the analogue NMT system and who's subscribers could roam to neighboring countries. But international roaming on a European and later global level was a novel and breakthrough technical feature and idea in the heads of the people who created GSM at the time. It radically ended an era in which people had to remove the telephone equipment installed in their car's trunks (few could afford it obviously) if they wanted to go abroad, or to alternatively seal the system or to sign a declaration that they would not use their wireless equipment after crossing a border. Taking a mobile phone in your pocket over a border and use it hundreds or thousands of kilometers away from one's one home country was a concept few could have imagined then. And that was only 30 years ago…

P.S.: The phone in the image with the GSM logo on it is one of the very first GSM phones from back in 1992.

Over the years I've come up wit a number of ways to trace the network traffic from and two a smartphone for various purposes. So far they all had in common that the setup took some time, effort and in some cases bulk hardware. So in quite a number of cases I shied away from taking a trace as the setup just took to long. But now I've come up with a hardware solution for Wi-Fi tracing that isn't bulky and set-up in 60 seconds.

Earlier this year I bought an Edimax USB powered Wi-Fi mini access point that I have since used many times to distribute hotel and office Wi-Fi networks to my devices. Apart from being small it's easy to configure and ready in less than a minute after being plugged into the USB port for power. To trace the exchange of data with a smartphone it only needs to be connected via Ethernet to the Ethernet port of my notebook that is connected to the Internet via another network interface, e.g. its own Wi-Fi card. In addition, the Internet sharing has to be activated for the Ethernet port of the PC. This is supported in Windows and also in Ubuntu in the network configuration settings.

Once done, Wireshark can be used to monitor all traffic over the Ethernet interface. If the smartphone is the only device served by the mini access point, only its traffic traverses the Ethernet interface and from there the Wi-Fi while the notebook's traffic goes directly to the notebook's Wi-Fi adapter. That means no special filtering of any sort is required to isolate data flowing to and from the smartphone. The figure on the left shows the setup. Super easy and super quick to setup.

While in Europe there are few network operators if any at this point in time thinking openly about shutting down their 2G GSM networks, network operators in other parts of the world are seriously contemplating it or have already done it.

One of the very first operators that shut down its 2G network was NTTDoCoMo in Japan. Agreed, it was a special case, it wasn't GSM it was a local proprietary solution, but still. Last year, AT&T has announced that they will shut down their GSM network in 2017. That's not so far away anymore and from what I can tell they are serious about it. And the latest example is a network operator in Macau according to this post on Telegeography. O.k. that's a special case again but still the number of 2G network shutdowns is growing.

It makes me wonder how much longer it will take in Europe before first operators seriously contemplate a move. Two or three years ago I still saw a meaning of having 2G EDGE networks in the countryside. Web pages were smaller than today, smartphone penetration was nowhere near today's level and web browsing over EDGE was still working, especially with network side compression. But today it has almost become impossible. As soon as there's only 2G network coverage in an area, all smartphones drop on that EDGE signal that completely becomes overburdened. And then there's the size of web pages that keeps growing and even smartphone optimized version of web pages come with lots of JavaScript and other niceties. It has come to the point that I have switched off 2G in my smartphone not only because there's no Wideband AMR but also because falling back to EDGE for data is just useless anyway.

Sure there are perhaps quite a number of 2G-only embedded modules in machines today (including the block heater of my car and my GSM controllable power socket) and 2G only mobiles in the hands of people. But I guess their number will not dwindle before an announcement is made. Sure, there will be lots of complaints especially from the embedded side.This makes me wonder how the story will look like in Europe!? With multi-RAT base stations it might not be very costly to keep GSM running in the future. As traffic goes down on GSM one could re-farm the spectrum and put LTE in the freed space or extend the bandwidth of existing LTE carriers. That inevitably means LTE will be deployed in many different bands simultaneously which will require efficient load balancing algorithms between the different carriers. But compared to other features such as SON, HetNet, etc. that should be rather simple to accomplish.

5 years ago I already speculated about the conditions for GSM phaseout and potential exit scenarios on this blog. Have a look here. The reasons for keeping a GSM network I listed 5 years ago are pretty much no longer here due to the emergence of LTE on high and low frequency bands and 3G devices now including the 900 band for Europe and at least two or three roaming bands. Good to see how technology has advanced. So let's see which of the exit scenarios I described in that five year old blog post will be used.

When I recently flew over a big city in the very early hours of the morning I was amazed how many lights I could see despite most people being sound asleep. Tiny dots of light everywhere. What struck me then is that in our society, electrical power is so important and cheaply available that wires are dragged everywhere. There's a light bulb every couple of meters, obviously far more than than there are cellular base stations in the city. While cellular networks as we know them today have mobilized the Internet and brought it to many places there are still many many places even in well covered cities inside buildings and also outside with inadequate coverage. But even in these places there's electricity for lighting and many other purposes. As the importance of the Internet continues to rise it made me wonder if at some point we'll see a shift towards networks that are built in a similar way our electrical grid works today: There's a wire with a small transciever at the end dragged basically everywhere.

Light does not come from a central place. Instead, individual small light bulbs cover a small area. So perhaps we'll see a similar evolution in mobile networks!? Obviously, that's easier said than done as there are significant differences between the power grid and wireless networks:

First, there's usually no unwanted interference between two light bulbs compared to two radio transmitters that are close together. Also, transporting electrical power through a cable is much simpler than a multi megabit stream of data. But then we've transported electrical power through cables for a century and more now and technology has evolved. Another big difference is while wireless networks serve the public, wires for electrical power are usually put in place because the owner of a building requires power at a location for his own purpose and not for the public. Even lighting in public places follows a different rationale compared to wireless networks. In this scenario someone is interested in iluminating a place, e.g. for security reasons. What interest would someone have to install Internet connectivity in the same manner? And another challenge that comes to mind is that while the light bulb doesn't really care who delivers the power, wireless Internet connectivity is supplied by a number of different network operators, so installing little devices that distribute Internet connectivity would either require installing different boxes of different carriers or a new sort of device that could redistribute the connectivity of different providers.

But coming back to the basics, extending electrical power to the last corner is what we do in our society and it is done at an affordable price for the individual. It makes me wonder if something similar can be done in the Internet domain, how it will look like and how long it will take to realize it.

When I was in Seoul a year ago for the first time I was suffering a bit as Korea is one of the few countries I traveled to that didn't have prepaid SIMs for mobile Internet access. But the world keeps changing, I thought, so before going to Seoul again recently I did a quick search on the Internet if the situation had changed. And indeed it had, there's now a KT Telecom MVNO called Evergreen offering prepaid voice and data services with SIM cards that can be bought in convenience stores at the airport. Eureka!

Of course I tried it out and the basic steps described here are quite simple. Following the instructions it took me only a few minutes to buy the SIM card for 30.000 Won (€21) with a balance of the same amount on it at Incheon airport. After a couple of minutes and one or two device reboots, again as per the instructions, the phone registered with the network. Fortunately the phone configured the APN on its own as there was no mention of it in the instructions. So far so good. In the default configuration, the 30.000 Won are good for around 590 MB of data (55.8 Won per MB) which is quite a lot already.

To get a higher data volume from the credit on the SIM it is possible to activate a data package, e.g. the 1GB package for 16.500 Won. This is were things get a bit tricky. The first step is to download the “Evergreen Mobile Services” App from the app store (Evergreen is the name of the MVNO on the KT Olleh network). The app can then be used to activate the data package. Unfortunately once that is done, Internet connectivity is cut because the service expects the user to top up this amount or to move the amount from the 30.000 Won from the voice bucket to the data bucket. The later operation can be done with the App but only if you find an alternative Internet access over Wi-Fi, as the connection was cut due to the activation of the bundle. No, that does not make sense and it's very inconvenient, but that's how it worked for me. After finding an open Wi-Fi access point I could then transfer the credit from the voice bucket to data bucket with the mobile app and Internet connectivity was restored instantly. A nice side benefit of activating the data option is that the remaining balance of the SIM card can be used for voice calls without cutting into the available data volume. So instead of 3 Euros a minute to Europe I only paid around 46 cents.

Apart from this slight activation hickup, the service worked well and I always got throughput rates of several megabits per second when I tired. So if the 590 MB are sufficient for your trip, don't bother with the activation of the data option. If you want more, make sure you have a Wi-Fi hotspot available before you attempt to activate a data bundle.

Pretty much whenever quarterly reports are presented by telecommunication operators these days there is the usual note about the difficult situation they are facing due to the investment required to keep networks up to the rising data demand. But is this really the case? The 2012 report of the German telecom regulator (in English) has some interesting numbers on that.

In 2012, invest in fixed and wireless telecommunication networks in Germany was around 6 billion Euros. That's the combined sum of invest of all market players. Hast it risen in recent years? Not according to the report. In reality, invest has remained pretty much stable over several years and compared to the overall revenue in 2012 of around 58 billion Euros that seems a quite reasonable number, at least to me (see page 81 of the report).

Let's have a look at some more related numbers: While invest has remained stable, the number of employees in the telecom sector went down from 184.200 to 176.000 in Germany and the pressure can be felt. End customer prices might also have shrunken but I would argue that this was mostly compensated with higher use. This is reflected in a slight revenue decline from around 60 billion Euros in 2009 to 58 billion Euros in 2012. But when looking at the EBIDTA of Vodafone Germany which for 2012 was 3.359 billion Euros out of a revenue of 9.641 billion Euros then I don't really see big suffering.

Once a year many telecom regulators in Europe publish their yearly analysis of the state of competition in the telecommunication market. A while ago, the German regulator has published it's report for 2012 (in English) which contains, among many many other interesting numbers, the amount of data transported through fixed in wireless networks in Germany.

As per the report, 4.3 billion gigabytes of data were transported through fixed line networks in Germany in 2012 (page 77) compared to 0.139 billion gigabytes (or 139.75 million GB to sound more impressive) in wireless networks (page 78). In other words, there's 30 times more data flowing to and from fixed line connections compared to wireless.

According to the report there are 28 million fixed line Internet connections in Germany today and thus the average monthly amount of data per line is around 12 GB. Also interesting is the rise of fixed line data from 3.7 billion to 4.3 billion gigabytes from 2011 to 2012, that's a rise of 16%. In wireless networks the amount of data transferred rose from 93 million GB to 139 million. That's a 30% rise which is quite substantial but far from the doubling or tripling the year before and the year before that respectively. In other words, the growth has been slowing down for a number of years now.

The report further says that there were 139 million mobile subscribers in Germany in 2012 out of which around 40 million are actively transferring data (page 79). This made me think a bit. I pay around 40 euros a month for my fixed line Internet and telephony connection today and around the same amount for wireless connectivity. And while the fixed line is shared, every family member has an individual mobile contract. So in effect I pay less for my fixed line connection when broken down per user compared to my wireless subscription and on top transfer over 30 times more data over it. Or put the other way round I pay more for my mobile subscription then for my fixed line and use it far far less.

All of this makes sense if wireless networks are more expensive to build and maintain than fixed line networks. But is it really cheaper to drag a fiber cable close to people's homes these days and then have a copper wire to each individual house or apartment compared to setting up a base station on a rooftop that servers one thousand users? I have my doubts.

Which device will be my next smartphone? I've made my choice and it will be the Fairphone. It's in the process of being built by a small company established in the Netherlands and the aim is to produce it with the people and the environment in mind. No children labor in African mines, fair wages for Chinese works and safe working conditions. In addition the company is open about the whole process of building the device and using an open operating system, i.e. Android and perhaps Firefox OS and Ubuntu in the future.

The device is in production now with shipment foreseen around Christmas time. One interesting piece of information I recently came across when I wanted to get an update on their status is the cost breakdown of the device's retail price of €325 based on a production run of 25.000 devices. Here are some noteworthy numbers:

• €129 design, engineering, components, manufacturing

• €4.75 prototyping

• €4.25 reseller margin

• €9 certifications (CE, GCF, RoHS, FCC, Reach) and testing

• €63 taxes (VAT, etc.)

• €11.75 personnel costs, office space, IT, travel

• €11.00 legal, accounting

• €6 events

• €5.25 webshop hosting

• €18.25 warranty costs

• €11 interventions (sustainability, being fair to people and environment)

For the full details, see here. If you are interested in how a phone is built from scratch then the website is a treasure trove of information. Bring some time…

I was recently faced with the dauntingly tedious task of doing throughput testing which meant uploading and downloading files from HTTP and FTP servers and noting the average throughputs in each direction separately and simultaneously. This is fun for about 30 minutes if done by hand but gets very tedious and even confusing afterward as constantly triggering up- and downloads makes you loose your thread at some point when your mind wanders somewhere else during the downloads. So I decided to automate the process.

There must be about a zillion ways to do this and I chose to do it with cURL, a handy command line tool to upload and download files in just about any protocol used on the net, including http, ftp, pop, etc. etc. It's ultra configurable via the command line and has a great variety of output options that make later analysis such as averaging downloads speeds of different files very simple.

For doing repetitive downloads I came up with the bash script (works well under Ubuntu and MacOS):

#!/bin/bash
URL="http://ftp.xyz.com/name-of-file"
OUTFILE=test-down.csv
rm test-down.csv
curl $URL -o /dev/null -w '%{size_download}, %{speed_download}n' >>$OUTFILE
curl $URL -o /dev/null -w '%{size_download}, %{speed_download}n' >>$OUTFILE
curl $URL -o /dev/null -w '%{size_download}, %{speed_download}n' >>$OUTFILE
cat $OUTFILE

The URL variable holds the URL to the file to be downloaded. Obviously if you test high speed links, the server should have enough bandwidth available on its side for the purpose. The OUTFILE variable holds the name of the local file to which the file size and download speeds are written into. Then, the same curl instruction is run 3 times and each time, the result is appended to OUTFILE. While the script runs, each curl instruction outputs information about current speeds, percentage of the download completed, etc.

And here's my script for automated uploading:

#!/bin/bash
UPURL="http://xyz.com/test/upload.html"
LOCALFILE="10MB.zip"
OUTFILE="test-upload.csv"
rm $OUTFILE
curl  -d @$LOCALFILE $UPURL -o /dev/null -w '%{size_upload}, %{speed_upload}n' >> $OUTFILE
curl  -d @$LOCALFILE $UPURL -o /dev/null -w '%{size_upload}, %{speed_upload}n' >> $OUTFILE
cat $OUTFILE

The trick with this one is to find or build a web server as a sink for file uploads. The LOCALFILE variable holds the path and filename to be uploaded and OUTFILE contains the filename of the text file for the results.

Note the '.csv' file extensions of the OUTFILES which is convenient to import the results to a spreadsheet for further analysis.

When GSM was first launched in Europe a long long long time ago back in 19992 the GSM logo could quite often be seen in advertisements. It's gone a bit out of fashion in the past decade but every now and then I still stumble over it like in the image on the left I took in Bratislava. I've done a lot of research into the history of GSM but I could never find any information on the logo. Who designed it and what do the 4 dots you can see in the "M" of GSM signify. Who put them there? It's all a big mystery. If you know something about this, I'd be glad if you could share it in the comments below.