Category: Uncategorized

Let’s Prepare for 3GSM / Mobile World Congress 2008

Good preparation is everything, especially for the 3GSM / Mobile World Congress in Barcelona 2008. I am sure there will be lots of events happening in and around the congress/exhibition and as always it will be a bit difficult to keep track of all of them and select the interesting ones. This is why I thought I’d open a Wiki for everyone to share information about events, parties, job offers/seekers, apartment sharing, etc., etc.

It’s open for everyone, no registration required for editing. If you like the idea, bookmark the site and check regularly. If you know of an event or if you are the event organizer, consider leaving a note and link on the Wiki. If you organize an event but don’t want to create a web page for it feel free to create a new page on the Wiki for the details.

I already have one job seeker whom you might be able to help out:

Booth Hostess / Event Organizer

A friend of mine is looking for a job as booth hostess,
event organizer, or similar during the congress. She’s fluent in English,
French, Italian and German. She’s a proficient Internet and wireless
technologies user so she’ll be able to represent your company in a professional
manner. For her resume, please send me a quick email to gsmumts (at) gmx.de

Oh yes, and before I forget the Wiki has RSS feeds for new and updated pages which makes keeping track easier.

If you like the idea, please spread the word on your blog, by eMail, word of mouth, etc. 🙂

Android 3G phone as a Wifi access point?

About a year ago I’ve written a blog post about how nice it would be if Nokia N-series phones with 3G and Wifi could be used as a Wifi access point. The post keeps getting a lot of hits via search engines and a lot of comments have been left until the comments section was closed automatically to reduce comment spam. Looks like I am not the only one thinking about such a feature. A year later a solution or rather workaround seems to have surfaced at least for some Windows Mobile devices. These days I am wondering if Google’s Android platform for mobile devices might be the choice for some people to really implement such a feature!?

So why on Android? The answer is Open Source! Windows Mobile, S60 and other mobile phone operating systems are closed source. Application developers can only use the Application Programming Interface (API) of the operating system which simply does not allow programmers to do such low layer things as reconfiguring the Wifi chip, setting up a system wide DHCP and DNS proxy and to interconnect the Wifi interface with the 3.5G interface. But with Android, things are different. The operating system is Linux so the source code and programing tools to modify the operating system are available. So as they say in the video below at the end, "start composing"!

Oh, by the way, there are already some open source mobile devices out there, the Nokia Internet Tablets (N770, N800, N810). Their operating system called Memo is also based on Linux and there is lots of activity in the filed. The latest version of the software even ships with an Xterm so deep diving without installing additional software is possible. There are even some tools ported from mainstream Linux to tweak the Wifi chip. Won’t help much on these devices for a Wifi/3.5G access point since the Internet tablets do not have a 3.5G Interface. Nevertheless it shows the possibilities.

Let’s see who gets there first, closed source or open source. Where do you place your bets?

My Crazy Phone Numbers

As both my private and my business life is pretty international I would estimate that 80% of my calls are international these days. Most of these calls are carried over VoIP for some of the distance. Interestingly, that has some strange consequences for the phone number that the other end is shown. Some examples:

Business calls: I use a SIP VoIP client on the PC and the SIP network of my company for most business calls. To reduce cost, my company has a lot of voice gateways deployed in different countries. The IP network thus transports the VoIP call to the closest media gateway and then releases the call to the public circuit switched network. As a result the caller always sees a local number instead of my real number. Nice to hide the fact that you are not actually in the country. However, the number can not be called back.

For private calls I use Skype a lot. Skype does similar things and has gateways in many countries to release the call to the public telephone network as close to the destination as possible. Again a mysterious local number is shown (e.g. +491234). Most people are quite surprised to see such a number.

When I am in Germany and have to call a mobile phone abroad I use one of the many alternative PSTN operators. Again the number that is shown looks funny and has nothing to do with my real number.

And when I am out and about and want to call abroad from the mobile I use the services of Rebtel which lets me call a national number and then forwards the call internationally at a fraction of the cost of a direct call from the mobile. Again, same story with the calling number being displayed on the other end.

So why is there a number displayed at all at the other end if it is just fictuous? Nobody ever heard of CLIR?

P.S.: I wonder if there is a law prohibiting media gateways in a country to send the international number from a different country!?

P.P.S.: For the moment I seem to be the exception. So most people these days pick up the phone and say: “The number looks funny, this must be you, Martin!”. Sort of an alternative caller ID…

Broadband Internet via 2-way Astra Satellite

Every now and then I get an eMail from someone asking me for advice on how to best hook up to the Internet from that little cottage they have bought in a remote place in Italy. Not quite sure why it’s always Italy, seems to be a nice place for a cottage. If 3G is not available their best chance so far was to buy a prepaid SIM card from TIM and use their nationwide EDGE network. But it seems there is no an affordable alternative available.

SES Astra has started their broadband Internet satellite service that does not require a phone line for the return path. The receiver/transmitter requires a satellite dish or, in case a satellite dish is already installed for reception of TV programs from the Astra satellite, the receiver/transmitter can be installed alongside the TV receiver module.

It seems the service is not sold directly by Astra but via national resellers. In Germany, Filiago is the reseller. A flatrate with 1 MBit/s downlink and 128 kbit/s uplink is available for around 40 euros a month.

According to Astra the service is available throughout Europe. Very nice!

TDD UL and DL Ratios and Uplink Speeds

An interesting technical detail came to my attention today concerning Time Division Duplex (TDD) wireless systems such as WiMAX: Since uplink and downlink transmission is done in the same frequency band, uplink and downlink capacity can be adjusted based on demand. In theory this is an advantage over FDD (Frquency Division Duplex), used by most cellular 2G and 3G systems today. Here, uplink transmissions use a seperate frequency band which is just as large as the downlink frequency band (e.g. 5 MHz for UMTS). This means that FDD systems always have a 1:1 ratio between uplink and downlink. With TDD systems, this ratio can be changed, for example to 2:1, 3:1, etc. to give more capacity to the downlink. But there is one important thing to remember: The efficiency of uplink transmissions is much lower than in the downlink due to the lower transmission power and small antennas of the mobile device. Thus, even with a 1:1 ratio, uplink data rates are far lower than data rates in the downlink despite the using the same amount of bandwidth. I estimate that the maximum overall speed achieved in uplink direction is only 1/3 or 1/4 of the downlink. With rising uplink requirements of web 2.0 applications (picture, video uploads for example) I wonder if it will even make sense in practice to configure a 2:1 or 3:1 ratio in TDD systems as the uplink capacity would then be only a tenth of that of the downlink!? Opinions, anyone?

NokiaWorld: Chris Anderson and What Happens When Things Become Almost Free

Not much news from NokiaWorld which took place this week in Amsterdam concerning the hardware side. No cool N95 successor announced, no mind blowing N93+++ in the pipe. I am a bit disappointed. But the presentations of the guest speakers made up for it a bit. A lot of videos of what happened can be found here. I’ll surely take a look at most of them in the next couple of days. I’ve watched Chris Anderson’s presentation today on the impact of things that almost become free. For a minute he speculated what would happen if Nokia gave away the phone for free and charged for services. Well, I would "buy" a new phone instantly 🙂

Mowser and a Good Mobile Search Experience

I don’t search a lot on the net from my N93 as I don’t really feel the need for discovering new information sources while on the go. Today, however, I had to do a quick search as I had forgotten the exact address of a café in Paris I was going to. So I used Mowser for the search since it would also format any pages it would find in a mobile friendly way. To my great surprise it found the address right away and displayed it as part of the search results. Great stuff, so mobile search is useful for me afterall.