Category: Uncategorized

There are lots of political discussions around Google books these days but this short blog just focuses on a cool feature I just found. I've got lots of good books on wireless topics at home but when searching for a specific piece of information it often takes a long time to find it, even if I know in which book I could find the answer. So I usually turn to Google first to see what the search engine can come up with before I start flipping through and index or the table of contents of a book.

So one of these days I wanted to find out what the A1 event in LTE is all about. So I typed "LTE A1 event" into the Google search engine and one of the first entries in the result list was a book on Google books which had the answer. Google books gives me a page number and a preview of the page. In this particular case I had the book on the bookshelf already so I could go directly to the page and read the whole subsection on the topic. Excellent!

Here's an interesting comparison of how much spectrum is used today for 3G vs. Wi-Fi. In Europe, UMTS/HSPAS is assigned a 60 MHz uplink + 60 MHz downlink = 120 MHz. Out of that only 20+20 = 40 MHz are in active use today even in dense urban areas except for a few exemptions. For details, see here and here. In the future, the digital dividend band in the 800 MHz band (2×35 MHz), and the IMT extension band in 2.6 GHz (2×70 MHz) will be added.

Wi-Fi 802.11b and g use the 2.4 GHz band spanning 80 MHz. Especially in dense urban areas, I'd say that's already used quite intensively these days. In addition, some 802.11n kit can also use the 5 GHz band, where almost 400 MHz is allocated for Wi-Fi and other short range wireless systems. It's probably still not used a lot but with more and more 5 GHz band enabled equipment appearing that will certainly change.

So, what's the message here? There are several. 3G only uses a fraction of the spectrum that is already allocated today without suffering massive bandwidth bottlenecks. The same applies to Wi-Fi although the original 2.4 GHz band is already quite busy. But if your gut feeling told you that cellular networks probably had much more spectrum available than Wi-Fi, then that was not quite accurate.

Yes, like many others, I am waiting for the release of the Nokia N900 and I have lots of good reasons for it. But there's one thing I really need on that device before I can use it: Opera Mini. True, in all the videos, the browser looks great. However, try using the browser with EDGE and frequent loss of signal. Quite a different experience under such circumstances.

I've used Opera Mini for years now and just under such circumstances, which happen more often than not when traveling, it really excels. But I am afraid that with the N900 we have to wait a bit for the browser as it is a Java ME application, an environment the N900 does not support (yet). So anyone heard of Java ME being added to the N900 software repository or Opera working on a port of their Mini for Maemo Linux?

Here's a mystery I can't quite figure out so I thought I'd write about it to see what you think: There are a number of VoIP services I use frequently over a DSL link and they all work well. Over a 3G wireless connection, however, SIP via Sipgate.de isn't working as it should. While there is almost no noticeable delay in the speech path in downlink direction, the uplink speech path has a delay of almost 1000 ms!

One might argue, that's a 3G issue, but it definitely is not, as the delay in Skype in both directions is just fine. O.k. so maybe it's a combination of the mobile device I use for my SIP calls, a Nokia N95, and the 3G router that's causing this. No, I can rule that out, too, since I've tried it with a Huawei D100 3G router as well as with my Fritzbox DSL/3G router from AVM. I also use the Fritzbox over DSL and the N95 works well over that backhaul link, so that can't be the issue either.

My final idea: Maybe something is done in the network!? Possible but unlikely as the behavior is the same in Vodafone's network in Germany, the Mobilkom A1 network in Austria and Wind's network in Italy.

Other ideas, anyone?

A bit late with this one but in case you haven't seen in elsewhere yet, this week's Carnival of the Mobilists has been taken over by Tsahi Levent-Levi and the VoIP Survivor blog. As always, a great read so head over and enjoy!

Here's an interesting article I've recently discovered in The Economist on mobile banking solutions in Africa and Asia such as MPesa and others. In my opinion the article contains good information on how such services work, how people benefit from them and the issues encountered with the local banking system and regulators. Also quite interesting are the many comments which contain quite different points of view so be sure to check them out as well.

Self observation today: How is the daily morning news best consumed during breakfast? From a mobile device, TV or a plain good old newspaper? I guess the answer depends on whom you ask but I strongly prefer a mobile device for a simple reason: I can get to the news that interests me quickly, i.e. I decide, and it can be easily held and navigated on with one hand while the other hand takes care of breakfast.

With news on the TV I am not in charge so that's a no-go for me. And with the newspaper, I need both hands and my table is just not big enough so I can put it down. Sure it can be folded etc. but that won't help much as each time you are done with half a page both hands need to come back into action to "navigate" to the next page. There we go, my preference. How do you consume the morning news?

Average Revenue Per User, or ARPU, is a measure often used when discussing financial results of mobile network operators. But in this day and age, ARPU has become pretty much irrelevant as discussed here. Still it is used a lot. Finally, I've recently seen a refreshingly different approach being used by the London Times. Instead of reporting ARPU, network operator performance was assessed in market share and revenue terms. That makes a lot of sense to me!

All network operators need to build a nationwide network to compete. So comparing the market share between operators makes sense to me because each network operator has a similar network to build and support. How thoroughly and thin-meshed that network is built is another matter. That distorts the market share picture a bit. So maybe one should add the number of base stations into the equation?

As always, comments are welcome!

Ubuntu keeps surprising me positiviely! A few days ago I installed the OS on my somewhat older desktop computer as well, not really hoping that I could reuse the PCI Wi-Fi card inside. That was because I thought the card was broken as under Windows and the native driver it always stopped working after a while and would only come back after a reboot.

Surprise surprise with Ubuntu! Not only did it recognize the card instantly without the need to install an extra driver it is also rock solid and hasn’t stopped working after hours of using it. Looks like it wasn’t the hardware after all but just a crappy Windows driver installation by the manufacturer of the card. Incredible! While the manufacturer has long given up on the card, it works like a charm under the free OS and is much more stable. What more can you want?

The last couple of times I went to the bakery around the corner I noticed a Blackberry behind the counter. Being more intrigued every time I passed by I finally asked what the device is used for.

So I was told that the bakery is introducing an electronic ordering solution and Blackberries in their outlets are used to quickly update and change daily orders via a program running on the Blackberry which communicates with the central ordering system over the cellular network. Quite a step forward in flexibility from manually filling out an order sheet once a week for a full week in advance.

Also, compared to a more traditional setup with a PC and potential dial up or DSL access, this costs much less and takes no additional space. Maybe over time, the outlets can even cancel their fixed line phone as the Blackberry can easily substitute that as well.

And best of all, despite the introduction only being in an early beta and the software not quite stable, the non-technical user of the system I spoke to actually liked it and said she much preferred it over the old system as she can react immediately to special orders. What more do you want…