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If you are a frequent reader to this blog you have probably noticed that I am running Ubuntu on my netbook for a couple of years now as it is fast and slick on such limited hardware and, of course, it's open source. But there are a few tasks for which I still prefer Windows software, for which I use Wine to use it in Ubuntu.

One of these is the Windows TightVNC Remote Desktop Client, which for my purposes is much better suited than Ubuntu's built in Vinagre VNC Client. Especially the "scaling" option that let's me scale down the remote desktop which tremendously helps if it is vastly bigger than the small netbook screen is sadly missing. Also, the built-in client does not show me the local mouse pointer which kills usability as it makes moving the remote mouse pointer precisely very arduous.

But o.k. I use Wine to run the Windows application in Ubuntu and it does the trick, even if the scaled down image of the desktop does not look as nice as if the program ran on a real Windows machine. However, it has its limits, too. When I recently tried to remotely administer another Ubuntu machine with it, I found it to be unstable with Vine as the VNC server on the other end. So I switched back to Vinagre just to be disappointed again by the missing local mouse pointer. Time to do search for an alternative. And the alternative I found is quite stunning. It's called Remmina and can be installed right via the Ubuntu package manager.

Not only does Remmina have a seamless scaling option that beautifully reduces the size of the remote desktop but it also has a full screen view in which the desktop moves when the mouse pointer hits the screen limit in case the remote desktop is still biger even after scaling down. Also, it handles both Windows 7 and Ubuntu client desktops without any hicups. Perfect! Furthermore, it has a reverse VNC functionality, i.e. the remote desktop can establish a connection to the client. I use this quite frequently when the remote desktop is behind a NAT in which the TCP port required for the incoming VNC session is not forwarded. In this case the user of the remote computer needs to establish a reverse connection. Very simple on Windows but unfortunately not built into the Ubuntu remote desktop server Vino. Again a simple fix: After installing X11Vnc from the package repository, a reverse VNC session can be established with a simple command: "x11vnc -connect YOURIPADDRESS". Easy to put in a shell script which is then linked to an icon on the desktop. This way, the remote user doesn't even have to type in anything.

And finally, another very important thing Remmina and X11Vnc do is to adapt to the connection being established over the Internet, i.e. much less bandwidth than in a local network. Compression is automatically activated with a good balance between good looks and speed.

Internet Access in the air is once again in the air, so to speak. A couple of months ago, Lufthansa has restarted their on board Internet access again after a pause of several years. On my way back from New York at the time of this writing, I had the fortune to be one one of the planes with a satellite dish on top. Great stuff and I am posting this from over the Atlantic ocean. Download speeds are in the range of 2.5 MBit/s, although the speed is quite variable. Uplink speed is 500 kbit/s and the round trip delay time is around 700 ms from the position you can see in the picture on the left. Time for some sleep now though, with Internet access or not. Good night.

For the second time in so many days I've seen someone sitting in a New York Starbucks and using his/her iPhone/iPad to make a video call. Videocalling has been with us for many years now and was popular to some extent in some countries, as reported here for example already in 2006. However, on a global scale it was never a big success. So twice in two days over an IP based technology now. Looks like there is potential after all, perhaps due to a different pricing proposition…

There is one thing, all current mobile Voice over IP approaches have in common, be they VoLTE, VoLGA or Over-the-Top VoIP applications such as Skype:

Traditional mobile voice services are an integral part of the baseband radio chip and in the case of Android, for example, the user interface that runs on the application processor as part of the operating system communicates with the baseband radio chip with AT commands to establish and tear down a voice call. In other words there's not much to do for the operating system itself except for issuing a couple of commands. All the rest is done in the baseband chip, including voice processing and handovers between different radio access technologies such as UMTS and GSM.

As soon as any VoIP technology is used, and that's what they have in common, all these things move up from the baseband processor to the application processor and the operating system. What stays in the baseband is the handover management between different cells of the same radio technology and, for some VoIP variants if implemented, the enforcement of quality of service.

This means that there is a fundamental shift in who delivers the software for making voice calls on mobile devices in the future. Today it's the baseband chip vendor. For VoIP, it's going to be a third party from a network operator's point of view. Google, Microsoft and others will push ahead with their own voice services that will run over IP, no matter what kind of transfer network is used. This way, those VoIP services are likely to be implemented tightly into the operating system. For mobile network operator VoIP it's likely to be external companies that will offer plug-ins for popular smartphone operating systems. Easily done with Android, as can be seen for example with GAN clients from Kineto today. But what about smartphones that are not bought via a newtork operator, will they have those "plug-ins' as well? And how about closed operating systems such as those from Apple and Microsoft?

This also means that there is a catch for over the top VoIP solutions that are completely transport network independent: They will topple over as soon as the device has to select a 2G network which can't transport the IP packets anymore. Also, it might take a while for handover procedures between LTE and UMTS to mature and be quick enough to keep the the interruption time in acceptable limits. The only thing that helps is to make LTE (or UMTS) as ubiquitous as GSM. Not impossible but I don't see it happening in the next couple of years.

Network operators supplied VoIP solutions have one big advantage, though: They can interact directly with the network over the network signaling layer. This is coordinated in the baseband chip and the network operator's VoIP server and thus, VoIP calls can be handed over to circuit switched channels once the only option to continue the call is a 2G network. However, that's far from being trivial as it requires a very tight integration of the VoIP service (i.e. the IMS) with the current circuit switched MSC architecture. For details see my post from back in 2008 on IMS Centralized Services.

Also not to be underestimated are the potentially higher power requirements of running everything in software and using a transport network that is optimized for high speed data. I wonder how that compares to processing a voice call in a dedicated hardware unit as it is done today and using a transport network (GSM) that is highly optimized, also from a power consumption point of view, for transporting voice frames. For some users, this is perhaps less of a problem as they are now substituting voice calls for other forms of communication such as instant messaging, Facebook, Twitter, etc. and hence have a reduced need for mobile voice. But the number of voice minutes per person per month doesn't seem to fall, so I wouldn't bet on this issue just going away like this.

All things mentioned are not insurmountable but it will take a lot of dedication and effort to tackle them.

I've already stumbled a couple of times over the term "HetNet", a 3GPP work item in LTE-Advanced and an abbreviation for "Heterogeneous Networks". However, it has so far always remained somewhat of a mystery work item to me and I wasn't really sure what people where after here. But after watching this 4 minute HetNet Intro video from Ericsson it's much clearer now.

In essence, one of the aims of HetNets as explained in the video is to make the best use of the spectrum in areas where macro and pico base stations will be deployed in parallel. When a mobile is close to a pico base station it should use it, obviously, and fall back to the macro network once it leaves the coverage area or once the macro network can serve it better in terms of downlink throughput. However, there is a grey zone in which the downlink is better served from the macro network while the uplink would be better served by the pico base station. This imbalance is caused by the higher transmit power of the base station compared to the mobile and the pico cell. In the uplink, on the other hand, distance matters more due to the limited output power of the mobile device. 

So one of the things required for efficient HetNets is a way to handle the uplink and downlink data transmissions of a mobile device to/from/with different base stations. Quite a tricky thing as close co-operation between the pico and macro layer is required.

And for more information on the topic, I can highly recommend this recent whitepaper from Ericsson on Heterogeneous Networks. Bring some time though to read it, this is not a 5 minute pitch.

A couple of months ago, Eutelsat launched a next generation satellite (KA-SAT) for Internet access in Europe and it seems it has ended up in the right orbit and it will be taken into service shortly. Especially one number is quite interesting: The satellite is said to have a capacity of 70 GBit/s, that's 70.000 MBit/s. If you divide this by the capacity of a big fat LTE base station would have, let's say 70 MBit/s to make the calculation easy, that corresponds to 1.000 base stations.

Obviously a little dish is required to communicate with the satellite so it is for stationary use only. But for rural Internet access at home that doesn't really matter beyond getting it set-up in the first place. 1.000 base stations shot into orbit, an interesting picture to visualize.

I've recently had the chance to put my hands on a Siemens P1, one of the first GSM phones from back in 1992, sold to end customers about one year after the official launch of the first GSM networks on the 1st of July 1991 as reported in two previous posts here and here. Two things fascinate me about this phone:

First, its (comparatively) enormous size. It's already portable, but bulky and heavy and the antenna with its metallic socket alone weighs more than my current smart phone.

This is where we have come from in modern digital mobile communication, 19 years ago, bulky and supporting a data rate for voice communication of roughly 20 kbit/s (including the coding overhead). And it came at a cost of well over 1500 Euros, which 20 years ago was an even higher price than it sounds today.

Today, mobile devices are a fraction of the size and cost, voice telephony is but one of many applications now integrated and data rates have soared beyond 100 MBit/s with the latest LTE chips. In other words, a speed-up factor of 5000. Compare that to cars for example and how many cars from back then are still on the road. Quite a number of them. In other words, the life cycle of cars is an order of a magnitude longer than that of mobile phones. More true today than ever.

And the second thing that fascinates me about the P1 is that the phone still works today (starting with software version 18.6.1993). It's a bit picky about SIM cards but I managed to find one that works with it. Another nice thing is the start-up time, well, or rather the absence of it. You hit the power button and it is on. Instantly. Not everything went in the right direction in the last 19 years…

Other GSM phone manufactuers of the day that could deliver something in 1992: Orbitel, Motorola, Panasonic and Nokia. A bit later, in 1993 more companies could finally deliver soemthing. Names like Alcatel, AEG and PKI are mentioned here. Interesting how few of them have survived over time and who dominates the market today.

As reported in the press and here yesterday, it's been 20 years since the first GSM call was made in a commercial network. July 1st 1991, what's behind the date? According to this book on the history of GSM in Germany, published in 1994 (!), the date was set already in the mid 1980's as the official launch date in all European countries (see page 274). But as always ever since, networks are launched without really having mobile devices to use them. Let me quote from that page (translated from German):

"The fathers [of GSM] had agreed in the concert of the post ministers in the middle of the 1980 on 1. July 1991 [as the launch date]. A glittering celebration, moved by the thought of European harmonization should have been celebrated in all of Europe. But it didn't work out. The launch date burst like a big and colorful soap bubble. It burst among other reasons because many other nations [other than Germany] were not in a hurry to launch their GSM networks for a variety of reasons. In Germany, however, things were prepared for a timely launch. But even here nothing happened on 1st July 1991. Only a full year later could the age of GSM finally begin."

The book doesn't reveal whether a similar network launch like in Finland was done on that day as the text deals more with the availability of mobile phones that are actually sold to customers rather than making the first phone call with a pre-commercial device. From my point of view this does not in any way lessen what happened on the 1st July 1991, as a phone call is a phone call, no matter what the device was it was done with. So I come back with my question from the previous post: Where does that cable lead to from the headset the prime minister of Finland had in his hand? How big was that box?

So why where there no devices for the full launch in 1991? Now that's another interesting story and it involves network manufacturers, handset manufacturers, a company called Rhode & Schwarz and the threat of an interim type approval. But that's a story for another day 🙂

Lightreading, NSN and others report today that 20 years ago on this day, July 1st 1991, the first GSM phone call was made in a commercial network in Finland.  For the details have a look here and here.

So by all means, happy birthday GSM! Beyond the picture I’d really like to know to what kind of box that cable from the handset leads to!? How big was that first GSM phone used then?

Incidentally, a number of network operators in Germany have gone commercial today with their LTE networks. Just a coincidence?

And here’s a video clip of the event, enjoy!

 

This week I was at Medienforum NRW 2011 in Cologne to give a presentation on the technology behind LTE and also had the pleasure to attend a number of other presentations and discussion rounds as well.

One that surprised me in particular was a session on net neutrality. One of the participants and keynote speakers was Fritz Joussen, CEO of Vodafone Germany, a charismatic man that knows how to argue and entertain, in the company since the very beginning back in 1992. I expected to get quite a critical view on net neutrality from his point of view but was quite surprised about the following thoughts:

When asked if it is a good idea to charge content providers for access to the network or higher quality of service he said that he doesn't think it makes sense to develop a network "against the customer with the content provider" (" […] gegen eigene Kunden mit Inhalteanbieter.")

Further he said that he is of the opinion that if services are prevented to reach the customer the market as a whole will not happen ("Wenn Sie Dienste verbieten, wird der Markt hinterher nicht passieren").

And then: "I know where my money comes from, it comes from my subscribers".

And for those of you who speak German and still remember Boris Becker commercials for AOL back from the modem days I found this statement quite amusing concerning LTE and rural deployments: "Das ganze Dorf ist drin!" (sorry, no translation possible, the joke would be lost).