Author: Martin

I'm usually not very positive when it comes to mobile networks in France but today I have a positive story!

Like many other countries, France now has a fourth mobile network operator and competition has significantly increased. It has increased so much that a friend of mine decided to switch operators. We tried to get a better deal before switching but they were pretty much inflexible. It's this way or the highway was the message. O.k., so we took the highway and here's the story of how that went:

The only issue with switching operators in this case was that it was crucial to take the mobile number to the new network operator. There is Mobile Number Portability in France for some time now how but how long would it take to port the number and how long would the service interruption time be? We had no idea, 10 days to port the number was quoted in some forums but not much other information was available. But the pricing pressure was higher than the fear of service interruption and temporary numbers so we risked the step.

The new operator only sells prepaid and postpaid SIMs online which was much better for us anyway than going to a shop somewhere. The order process was swift and already included the necessary steps to get the mobile number ported. During the online order process the system requests that a call is made  to an automated system to get a porting identifier that then has to be given to the new network operator. That's all I thought, no forms to be filled out and mailed, no hassle, no nothing!? Well, that's almost too simple!? However, that was really all.

The SIM card arrived a couple of days later and after activating the SIM card, again via the web portal, by typing in the last three digits of the card-id, it was activated within 2 hours with a temporary number. During each step of the process an email arrived to confirm that the step was successful and with information about next steps and approximate durations. At this point the web site and the email confirmed the successful activation after about two hours and that the number portability process was now in its final stage. Three days maximum were promised for the number to be transferred. This was around 11 pm in the evening.

At around 7.20 am the next morning we received another email that the number is now ported. Wow, 8 hours later, very nice! The phone had to be restarted once as described in the email and then it just worked, the old number was on the new SIM card.

I have to say, I AM REALLY IMPRESSED!!! The process worked flawlessly, the information provided was clear, precise and accurate and everything worked very quickly. I have a lively imagination based on previous bad experience,  so after having been prepared for the worst, i.e. the number lost somewhere during the process, endless calls to hotlines of both network operators and two contracts running side by side for a couple of months you can't believe the joy I felt.

Very well done, finally something I am impressed about the French mobile landscape!

For ordinary files, the write speed of USB Flash sticks is probably of only secondary importance. However, when writing large files onto them, for example ISO images of Linux distributions or virtual machine images, write speed becomes an important factor.

Writing a 1 GB file to a slow USB flash disk at 1 Mbyte/s takes over 16 minutes while the same operation takes just over a minute when using a fast USB Flash disk that can write around 12 Mbyte/s to its Flash cells. And that's about the span I discovered on my various USB flash disks that have accumulated over the years. I have a couple of physically very small 4 GB USB sticks that hardly stick out from a USB port but the 1 Mbyte/s write speed is just measly. It's probably not due to their size as similar sized current models are advertised with write speeds of around 5-6 Mbyte/s.

Then I have a number of USB sticks with capacities between 2 GB and 16 GB of various sizes. Most of them are capable to write between 4.5 and 6.5 Mbyte/s to their flash cells. But that's still slow for 1+ GB sized files so I ordered a couple of 8 GB Transcend Ultra Speed USB sticks as they are rated for writing speeds of 12 Mbyte/s. And indeed, when testing them I could get 12.5 Mbyte/s of sustained writing speed out of them on sequential large file writes. Random write access is a bit slower, around 4.5 Mbyte/s.

When reading data on the sticks I see data rates between 20 Mbyte/s on the slowest ones up to 35 Mbyte/s on the Transcend Ultra Speed, which is pretty much the limit of the USB 2 port. Perhaps I should also try a USB 3 capable Flash stick. I don't have a USB 3 port on my PC but the write speed of these sticks seem to be again much faster.

The picture on the left shows the read and write speeds of the Transcend stick. The average write rate seems to be from random writes as writing a 1 GB file to resulted in a write rate of 12.5 Mbyte/s (timed with a watch, with unmount afterwards to ensure empty buffers).

There we go, with my cloud file sharing service dead in the water thanks to AVMs lousy software that they don't want to fix anytime soon I had to look for other options to turn the tide and convert a defeat into a victory. To recap, I sometimes need to share large files and don't want to use Dropbox like services that require my data to go out to a server somewhere on the web.

While thinking about alternatives I remembered that I once came accross ownCloud, an open source software that should do just what I wanted. And indeed after having taken a closer look it seemed to be exactly what I wanted. Then I remembered a low cost, low power computer called Rasperry Pi that runs Linux, perhaps a perfect base for running ownCloud inexpensively? And indeed, a Google search revealed how to install ownCloud on a Pi in just a few steps.

To see if ownCloud would be a solution for me, I downloaded a virtual machine image with a x86 Suse Linux base and ran it in Virtualbox on my PC. I came away very impressed about how easy it was to create users in ownCloud and how to share files by creating URLs in the browser. Also, uploading files via WebDAV as an additional convenience worked out of the box. Perfect! So I decided to go for the Raspberry solution and ordered one for next day delivery.

Needless to say I could hardly wait for its arrival but at least I could busy myself with preparing a couple of SD cards to boot it from. For a quick start, a Pi enthusiast has already created an SD card image with ownCloud preinstalled, so I used that for my first steps. In addition I downloaded the original Raspian Pi image to install ownCloud from scratch lateron.

As expected the Pi was delivered the next day and getting it up and running was as simple as connecting it to a mobile phone charger via USB to supply power and to plug in an Ethernet cable for connectivity. For the first experiments I also used a keyboard, mouse and monitor but quickly switched to a network only configuration as for the few cases in which I need a graphical user interface on the PI I can run that over the network using X11VNC.

Since I had ownCloud preconfigured on the SD card image I could log in immedately via the web browser and could start using it. With wired connectivity, I could read and write files at around 30 MBit/s. That doesn't sound like much at first but since the main use will later on be over Wi-Fi which is limited to around 25 Mbit/s at my place and over VDSL with a 5 Mbit/s uplink speed it is enough for my purpose. Also, the Pi only runs on around 2 Watts (!), which will only add around 3-4 Euros per year to my engery bill. So I think the 30 Mbit/s is a good compromise.

The final step was installing ownCloud on a plain Raspian image which also just took half an hour at most thanks to this tutorial, including the extra configuration for having a 5 GB system partition and a 10 GB data partition on the SD card and configuring the mount in fstab manually.

So for 60 Euros including the 16 GB SD card, a 3-4 euros per year power bill and a lot of fun setting the whole thing up I have my own file server now that I can use to share documents with other people on the fly. I really like that!

But of course I couldn't stop there because ownCloud can also synchronize calenders and address books between devices, something I don't want Google or anyone else do for me and from which I so far always refrained from. In a follow up post, I'll describe how that went. So stay tuned.

Back in December I was ecstatic when AVM released a new software version for my Fritzbox VDSL/Wi-Fi Router at home as they included a cloud file server system in the box that made it very easy to share large files with other people, which I sometimes do. And things worked pretty well for about a month ago until things suddenly started to go wrong.

I first noticed it when I got an email from a friend that the sharing URL I sent for a file stored on the Box was not working. I investigated and found out that the sharing link disappeared from the routers sharing links list. So I added it again and just to make sure rebooted the box. And gone it was again. Hm, o.k. so I added it again and told my friend to download the file immediately before my daily automated power interruption (for stability reasons) resets the link again. Lets fix this later I thought.

Then he told me that the link worked but the file download always terminates after around 30 MB. What!? So I tried myself and indeed, after 30 MBs the transfers to the outside world always terminated. Now this was getting really inconvenient. So I saved the configuration, made a complete firmware reset of the router and restored the configuration in the hope that the file sharing problem would go away. But unfortunately it didn't. Hours wasted on two problems and no fix in sight.

So I opted for the last resort and contacted tech support with a detailed description of my two problems. A couple of days later (what a joke) I got a response that the early file transfer termination is a known problem and would at some point be fixed. But they couldn't give me a date and also didn't mention if there's a fix in sight for the second problem with the disappearing sharing links after reboot.

Very disappointing really and I don't think it's going to be another Fritzbox for me in the future… I felt a bit stranded as I was left without a good solution for my use case as I don't want to use Dropbox and Co. But then I remembered that the other day I read something about a personal cloud service, OwnCloud, which finally saved the day. But that's a story for the next post.

When I was recently in a Starbucks and wanted to get some work done over a coffee I was quite surprised that despite good cellular network coverage, the Internet connection from my smartphone to the PC via Wi-Fi tethering was behaving very strangely. Needless to say that I started to investigate…

As I wanted to download a firmware image of a couple of hundred megabits I counted on the LTE network to give me adequate speed. But all I got was half a megabit per second and very erratic round trip delay times. Moving the smartphone sometimes helped for a second or two but then data rates were done and delay was up once again. O.K. so perhaps an LTE problem I thought, let's switch to UMTS. Strangely enough I encountered exactly the same problem there!? O.k. so perhaps the phone has a problem, lets restart it. But no, again the same problem afterward!?

Now I was a bit at a loss for a moment, what else could it be? Then I realized that there is one more wireless link, i.e. the  Wi-Fi connection between the smartphone and the PC. Perhaps something strange is going on there!? So I disabled auto-channel selection in the tethering configuration and manually set a channel. And voila, LTE became lightning fast, the download of the firmware image I needed started to run at 20 Mbit/s and everything was o.k. Interesting, something must have interfered on the 2.4 GHz channel the smartphone started the tethering hotspot on. Something to remember.

Some interesting statistics for this blog today. Here's a screenshot showing the top ten countries from where my blog is read. Unsurprisingly the US is due to its size and the language of the blog number one and the UK is number three. But apart from that the list is full of surprises. India is on number two of the list, and I can imagine it's due to the IT and telecoms industry there so I can understand that. But look at Sweden and Finland in place 4 and 5 respectively. With around 10 and 5 million people living in these countries it's quite surprising that they appear in the list. Ericsson and Nokia perhaps? Korea takes 10th place in the list, hello Samsung and LG I would imagine. China is completely missing and although I am not quite sure I think that's probably the great firewall blocking Typepad content…

Faintly similing as usual with a bit of sarcasm over the worthless Wi-Fi Internet access in Thalys trains I noticed that French and Belgian network operators have made their homework in recent years and have  installed 3G network coverage along the high speed train line. So I turned off the lousy on-board Wi-Fi and switched over to 3G to see how it fares at speeds of 300 km/h.

To my surprise it did really well. In most places between Paris and Brussels, I could get speeds of around half a megabit per second and web surfing and emailing felt hyper-fast. Only a slight hassle: At this speed you don't see the border sign between France and Belgium, i.e. you don't quite know when to reselect to another network.

There are two take aways from this: The first one is that this proves that UMTS works well at 300 km/h. And the second: Where there is a will, there's a way (and coverage)!

Once upon a time, not too long ago,
actually, perhaps 12 years ago or so, I got my first 1 Mbit/s ADSL
line at home. 1 Mbit/s in the downlink direction, mind you, and a
few hundred kilobit/s in the uplink direction. But it was fast,
really fast, compared to my previous modem and ISDN connections and
besides email, accessing information on the web designed for modem
speeds was the main use.

Fast forward to today and I argue that
especially for a family that same speed of 1 Mbit/s I had then in the
downlink direction is by far insufficient in the uplink direction
today. A single Skype video connection already saturates a 1 Mbit/s
uplink easily leaving little room for uplink communication of other
family members without compromsing video quality. Accessing files
stored at home remotely is also very limited with such an uplink. In
other words, I am quite happy that I have a VDSL line at home with a
5 Mbit/s uplink that I could easily upgrade to 10 Mbit/s if I wanted
to. However, I am still amazed that in some places, people get 20
Mbit/s ADSL lines with just 1 Mbit/s in the uplink direction.

At first I thought this was network
operator policy driven (yes, always assume the worst) but the ADSL
entry in Wikipedia reveals that even for ADSL2+ (without the Annex M
published in 2008), only 1 MBit/s uplink speeds were defined. And
even with Annex M, uplink speeds only reach 3.3 Mbit/s at best. In
other words, many will feel the consequences in the next couple of
years as their offspring uses the network ever more. Welcome to the
uplink bottleneck!

Being on the road quite a bit I have the need every now and then to use a printer or scanner at a friends place. When it comes to Windows, this is usually a bit of a dangerous thing to do if you are like me and like to keep the PC clean and fast. In the best case, the manufacturers CD is not needed and Windows finds a default printer driver after a
couple of endless minutes of hard drive activities and online driver
downloads. In the worst case, one has to resort to the original software of the manufacturer, which means installing hundreds of megabytes
of printer drivers and utilities of doubtful quality. Fortunately, I use Ubuntu Linux (12.04) on my PC and I was quite surprised at how simple and fast this has become. Read on for the details.

In the first instance I had to connect to to a simple HP color printer over USB. I can't remember the model anymore, probably because it was rather a non-installation as Ubuntu discovered the printer when I plugged it in and automatically installed the correct printer driver. I was quite surprised when I went to the printer settings to find that it was already installed. I guess it can't get any better than that…

A couple of weeks later I was faced with a brand new Canon Pixma MG2255, a printer, scanner and copier combination. Ubunutu's Canon support for this particular device was not as good as for the HP above as drivers were not installed automatically. When trying manually I managed to get a driver installed from the default list that would print a page or two but then stop working. A quick check on the net revealed that this is a common problem with an easy fix by getting the Linux drivers from Canon. Instead of downloading several hundred megabytes the drivers , it's size was only around 2 megabytes and installation took about a minute by double clicking on the included installation script.

When it came to the scanner part of the device I was a bit disappointed that it wouldn't work with xsane like my HP scanner at home. But Canon at least supplies its own Linux based scanner program (scangearmp), again via an easy installation archive. It's a bit of a basic scanning program that works quite well to scan single pages into png or pdf format but not much else. There's no option to collate several pages into a single PDF file and for each page a file name has to be given separately. Hm, would that really have been much extra work? Anyway, for manual multi-page scans a simple Linux shell command converts all PNG output files in a directory into a single PDF file with a good picture quality and reasonable file size (around 1.5 – 2 Mbytes per page):

convert *.png -resize 1020×1320 -units PixelsPerInch -density 120×120 scan.pdf

Agreed, a bit of tinkering is involved, but I much prefer that to my PC accumulating unused Windows printer utilities from different vendors that are difficult to impossible to get rid of again completely once not used anymore.

Back in 2009 I published the first edition of my Beyond 3G book giving an introduction to the technology of wireless networks, capacity forecasting, mobile voice, mobile device hardware and also the software running on them. It's been a tremendous success so I decided to update it and publish a second edition with a slightly changed title to address the launch of LTE networks: "3G, 4G and Beyond – Bringing Networks, Devices and the Web Together".

It is quite amazing what has changed since 2009. Many of the predictions I have made at the time have become a reality and new challenges and opportunities have arisen. While LTE was only on the distant horizon when the first edition was published, it is a reality today and HSPA networks have undergone a significant evolution as well. New spectrum bands have been assigned and auctioned in the meantime and many network operators around the globe have since made use of them to increase the coverage and capacity of their networks.

Perhaps the biggest evolution over the past five years has been on the mobile device side. Mobile operating systems dominating the market only a few years ago have almost vanished and new entrants such as Android and iOS have taken the mobile world by storm. On the web and application programming side, significant advances triggered an update of this chapter as well and I've even included a section that introduces Android programming to the reader.

As a consequence, about half the content of the previous edition of this book was updated or entirely rewritten to reflect the current state of the art and to give an outlook of what is to come in the next five years.

It's been fun and, needless to say, a tremendous amount of work to radically update the book this way. But besides staying up to date in all the different areas discussed in the book it's been an interesting way to experience the change of 3 years in one effort. As always, comments are very welcome and I am looking forward to the changes coming in the next couple of years.