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While doing some background reading I stumbled over the following optional Mobile Terminated Call procedure for a race condition:

The scenario: Just when the mobile network receives an incoming call for a user, the user's mobile changes to a cell which is controlled by a different mobile switching center. This results in a race condition, i.e. the previous MSC receives the call while the mobile is already performing a location update via the new MSC. If this is not treated, the mobile will not see the paging in the old cell and the call establishment fails.

This is where the "Mobile Terminating Roaming Retry Call" feature comes into play: If implemented, the previous MSC which has sent out the paging message to contact the mobile is informed of the location update by a "Cancel Location" message from the HLR. This is standard practice so far. However, instead of failing the paging procedure, e.g. after a timeout, the Cancel Location message is used as a trigger to signal to the Gateway MSC that the subscriber is no longer with this MSC. The Gateway MSC then releases the speech path to the previous MSC, runs another subscriber location search with the Home Location Register and then forwards the call to the new MSC. All quite elegant.

For details see 3GPP TS 23.018, chapter 5.2.1

I wonder, if this feature is widely implemented and used today? If you know, please let me know.

A short post today to link to the "Round the World Connected" Website of NSN. Great videos of how fixed and wireless communication systems are used around the world today and shaping our daily lives. They also have a video of the high-speed satellite based Internet on the Thalys trains which I used and reported on a couple of weeks ago. Have fun exploring!

This week the Carnival of the Mobilists has stopped over at Andrew Grill's London Calling blog. Especially Andrew's own entry on what IBM has done for the Wimbledon Tennis tournament last week from Twitter feeds to augmented reality applications caught my attention. I've followed augmented reality applications for a while and it's good to see they are entering the real world now. So without further ado, head over and enjoy.

A reader recently pointed me to a post by Joel Spolsky where he writes about 'Smart companies [should] try to commoditize their products' complements'. A very insightful article and he gives a number of examples for this business strategy:

• IBM's goal before they became a services company was to commoditize the PC add-in market.
• Microsoft's goal was to commoditize the PC market to drive their software sales.
• IBM's goal later on was to commoditize hardware and software by jumping on the Linux bandwagon to drive services sales.
• Companies supporting 'open source' in general are deriving value from selling services or hardware around it.

This got me thinking of what mobile network operators could commoditize to drive the revenue they can make from their product, the network!? A recent article by Dean Bubley might contain interesting insights into that. In his post 'Under-the-floor to Over-the-top', Dean writes about how Vodafone works on projects to become a service provider across networks and gives some examples such as a Vodafone branded Facebook plugin and an iPhone web-application. When looking at these moves from a 'Smart companies try to commoditize their products' complement' angle, these moves might be interpreted as "we try commoditizing services running on our network and thus we increase our revenue".

• directly, because more people will over time use our network and thus pay for Internet access / phone calls / SMS
• indirectly via branded over the top applications so next time people look for a new phone or a new pre-paid / post-paid subscription remember who's innovative in the space.

Comments, questions, insights?

P.S.: Maybe this is another way to get rid of the "dumb bit-pipe" thinking…

In the previous post I've described my first experience with an Acer Aspire One D250 netbook together with eeeBuntu (based on Ubuntu 9.04 Jauntry). I was quite impressed of how easy it was for the most part to get going. In this part I will look at how to get eeeBuntu working witch a 3G USB dongle and a mobile phone.

Easy Installation and Use

EeeBuntu detected both my Huawei E220 3G dongle and my Nokia N95 as wireless modems straight away, no configuration necessary. The first time they are connected, a configuration menu automatically appears which contains a pretty extensive network operator and APN settings list. After selecting a country and network, a profile is automatically created and added to the network list in the taskbar. Strangely enough, the menu entry did not appear straight away in all cases, sometimes a reboot was necessary when adding an new profile. In case the operator is not in the database, it’s possible to just select one of the operators and then edit the configuration by hand.

PIN protection Issue

Most of my SIM cards are not PIN protected so clicking on the new network profile entry connects to the network very quickly. With some of my SIMs, however, the PIN can’t be deactivated so the 3G dongle requires the PIN before launching the connection. While this worked pretty well the first day, I started to get problems since then and the behavior became pretty erratic. In the end, I wrote a shell script to send the PIN to the modem before using one of the 3G profiles.

Disconnecting and Status Information Missing

Disconnecting from the network also worked well via the network menu during my experiments the first day. Since then, however, for reasons unknown, clicking on “disconnect” has no effect, not with the E220 and also not with the N95. Unplugging the dongle or the mobile cuts the connection but brings further trouble. In many cases plugging the E220 back into the USB port has no effect and eeeBuntu needs to be rebooted. In Windows on the same machine, unplugging and plugging the dongle back in works well, so it’s not a hardware issue. With the N95 unplugging and plugging in again works in most cases.

Another thing that bugs me is that I have no means of seeing signal strength or to lock the 3G dongle to a certain operator or network technology as I can easily do in the launcher program provided for Windows. Too bad as this is a very handy functionality in some situations!

Summary

While the basic implementation for 3G connectivity works well, it is unfortunately a bit unreliable in eeeBuntu version 3. While I can maneuver around the issues, a normal user is likely to get frustrated.

This week the Carnival of the Mobilists is hosted over at mTrends. As couldn't be expected otherwise Mobile Web 2.0 evangelist Rudy de Waele has done an outstanding job of summarizing the best on mobile web writing of the last week in the Carnival and it's an interested read as always. Here's the link, so head over and enjoy.

A self observation today: Call it spring cleaning but today I felt like organizing the PC a bit and remove any unnecessary components and programs that just slow down the startup sequence and are no longer used anyway. One of the components that fell pray to this action is the Bluetooth protocol stack of my Bluetooth dongle as I noticed that I can't remember when I last used it.

In the past, I used Bluetooth for transferring files and pictures and every now and then also for connecting the notebook via a mobile phone to the Internet. I no longer do any of that:

For transferring files it takes pretty much the same time to find the Bluetooth dongle or finding a USB cable. In addition, file transfers are much faster and programs can work directly on the file system of the phone. Hence, no more Bluetooth. I wonder if it would be different if my notebook had Bluetooth built in? Probably, especially if the file system of the phone could be mounted as a virtual drive programs have access to.

As for the notebook tethering, a 3G USB dongle has taken over for two reasons. First, I am now usually using one SIM card for voice telephony and mobile phone Internet access and another SIM card in the 3G dongle. It has simply become affordable and it is much more practicable. And second, even while still using a phone for tethering I preferred a cable as the phone was charged over the cable automatically.

I still use Bluetooth for a number of other things like transferring contacts from the address book to another phone, transferring a picture I have taken to a friend's phone, for my mobile Bluetooth keyboard, and I can still imagine buying another Bluetooth headset with A2DP for high quality stereo transmission.

Nevertheless Bluetooth's usefullness for me is far lower than what it used to be. The cable has regained some territory. A bit odd.

In case you every now and then come by an LTE acronym you don't
quite understand (e.g. while reading the standards…), here's a great
resource that might help you in the future: As an online addition to
their book on LTE (LTE – The UMTS Long Term Evolution: From Theory to Practice)
Stefania Sesia, Issam Toufik and Matthew Baker have published a
dictionary on LTE acronyms. It's around 100 pages and very useful.
Highly recommended! Have a look at the left of the page, it's a bit
hidden (PDF Download under supplementary material)

Via: LTE Watch

Since I read "less walk more talk" I've become more aware of how mobile communication changes Africa. It's my impression that so far, voice, person to person SMS messaging and some information services again based on SMS (e.g. what are the prices for a certain goods in a certain city) have made the most impact. Also, the "mobile crop insurance" trial I've reported on here is an interesting project. And now, Grameen, Google and MTN have started new services to bring knowledge to rural areas around farming, health tips and trading. Again, based on SMS. Here's a video with some details. And for some more details from the inside perspective, have a look here.

Here we go, a long weekend was ahead so I took the opportunity to finally get a netbook for myself and start experimenting with it. After some deliberation, I got an Acer Aspire One 250 with a 3 cell battery and without Bluetooth for €299. Here's my report with my first impressions, how it works with Ubuntu Linux and how easy it is to get 3G connectivity working over a 3G dongle.

First, some specs. The D250 is quipped with a 10.1 inch display, a screen resolution of 1024×600 pixels, a 1.6 GHz Intel Atom processor, 1GB of RAM and a 160GB hard drive.

As I've seen on the original eeePC, Linux runs great on lower performance devices so I was keen to use Linux with this netbook as well. Unfortunately, most netbooks these days seem to be delivered with Windows XP only, so the first exercise was how to get Ubuntu installed without a CD or DVD drive.

Installation

I've seen on the net that eeeBuntu, an adaptation of Ubuntu Linux to the eeePC line of Asus supports the Acer Aspire series as well, so I decided to go for this distribution. To get eeeBuntu installed, the first step is to download the latest CD image from the web page and then install it on a USB memory stick that has a capacity of at least 1GB. Installing the image from Windows requires "unetbootin", a little tool that can be downloaded from the site as well. Once installed on the USB memory stick, the remaining procedure is pretty much straight forward as well. During a restart of the netbook, pressing the F10 key leads to the BIOS configuration menu where the boot device order can be changed to prefer USB media over the built in hard drive. The netbook then boots from the USB stick and enters the installation program. The first and crucial step is to partition the internal hard drive. To my great surprise and pleasure, it is not necessary to delete Windows from the hard drive. Instead, the Ubuntu partition manager allows to reduce the size of the Windows partition to make room for an extra partition for Linux. I evenly split the 160 GB between the two operating systems and I was up and running with both within a couple of minutes. Very nicely done, two thumbs up!

Hardware Compatibility

After booting for the first time, eeeBuntu configures itself for the hardware it finds. Most importantly, the graphics chip and the Wi-Fi were configured correctly and I could use the system right away without tweaking anything. The two devices that were not detected correctly and has since then resisted all attempts to get it working are the built in web cam and the Ethernet card. They work fine under Windows but won't do a thing under eeeBuntu. Still under investigation…

Fist impressions

After using the system for a day now, installing and configuring the desktop and the programs as I would like to have them, I am very impressed by the speed and stability of the system. Programs such as Firefox, Gimp and Openoffice load much faster than on my full size Windows XP notebook. One of the important benchmarks for me is the somewhat power hungry Typepad web editor for my blog. It turns out that it works great on the netbook, only marking text is a bit slow. Seems to be a Firefox issue, however, as the CPU utilisation remains low. Also, the startup time of the system is impressive. After a little less than one minute, the system is up and running. As you can see on the picture on the left, I created this blog post on the netbook to get a feeling for the keyboard. It's slightly smaller than a standard keyboard but after a couple of minutes I can easly and quickly type with 10 fingers with a similar speed as on a standard size keyboard. An absolute must for me!

So much for this post. In part 2, I'll go into the details of how to connect to the Internet with a 3G USB dongle or mobile phone and other things I found usable or not so usable over the first couple of days. Also an important question: How happy would a normob be with Ubuntu compared to Windows XP? To be continued.