Author: Martin

MWC 2010 – Nokia and Intel Announce the Merge of Maemo and Moblin

Meego In what I personally see as a big step in the right direction, Intel and Nokia today announced that they have decided to combine their efforts in the mobile Linux landscape and merge Intel's Moblin and Nokia's Maemo platform. The new OS will be called MeeGo.

From a Nokia point of view I think it makes a lot of sense. While it was laudable to have a Linux based open source operating system running on their mobile devices starting with the N900, I guess I was not the only one wondering how they would manage to garner widespread developer support. With Intel and Nokia now walking the open source path together, MeeGo opens the door for other device manufacturers to come along. Who those will be was not announced today but the initiative will rise and fall with this support.

I hope the initiative will bear fruit because, as the Nokia spokesperson said, this is a "no walls no fences" thing. I expect that means, among other things, that developers and users will not be restricted to app stores for application downloads. Not that I don't like app stores in general.They are great to easily deliver applications to consumers but they also limit creativity as developers have to get the blessing of the app store owner. So with MeeGo hosted at the Linux Foundation I hope applications can be installed by any means as we go forward just like today.

Qt shall be the application development platform of choice and Nokia and Intel promise easy cross platform development across Symbian and MeeGo. As Nokia has so far preferred ARM processors I assume the partnership means MeeGo will also support the Intel platform. Unless, of course, if Nokia's first MeeGo device is Intel based. For native code that means that two different compiles of an application might be necessary to run on all MeeGo devices, plus an additional compile for Symbian.

The Ovi Store will be used as app store and the OS targets not only smartphones but also netbooks, tablets and other larger screen devices yet to be invented. It's a whole mouth full, let's see how they execute. The right stuff for me anyhow!

MWC 2010 – First 3G Bandwidth Report

Here we go, day one of the Mobile World Congress in Barcelona and I've joined the crowd. The halls are filling up and the super heavily deployed 3G networks on the Fira are seeing their first heavy traffic of the day. Throughout the week I'll have a look at how Vodafone's network performs in different spots to get a feeling how much capacity is needed when tens of thousands of mobile enthusiasts meet in just a few exhibition halls. Why Vodafone? Because I bought a local prepaid SIM for Internet access and I expect their network to be one of the best.

When I was on the exhibition ground yesterday with 'only' exhibitors on site to get their booths ready I could get downlink data rates of around 450 kbytes/s in one of the cafés. The network was only lightly loaded. A good throughput but it's a bit low, I would have expected a bit more with a Cat 8 3G stick. Anyway, nothing to complain about really in the downlink. In uplink however, I could only get around 50 kbyte/s, an indication that HSUPA has not been activated in Vodafone's network yet!?

Today I am in hall 8, the main hall with the biggest stands and the biggest names in the industry all in one place. In total there are 4 UMTS cells of Vodafone in this hall with 3 carriers on the air. I assume the other 3 operators have similar setups but I'll have a closer look at them later. It's about one hour after the show has opened and the hall is already packed. At the Telefonica stand, my Vodafone network throughput ranges from 150-300 kbyte/s during a download. A good indication that there is some load on the carrier frequency my 3G stick has been assigned to and that the scheduler in the base station works on balancing the data bursts of the different users. Uplink speed is again at around 50 kbytes/.

And finally the web surfing quality is good, pages are instantly downloaded and VoIP calls over Skype just work fine, both in uplink and downlink. Very good!

MWC 2010 – Funicular de Montjuïc – Trip to Mobile Wasteland

Montj Here I am in Barcelona for Mobile World Congress 2010. I picked up my badge today to save myself the hassle of waiting in an endless line tomorrow morning and also to get a glimpse of what's going on inside, how everybody is scrambling to put their booth together. Later, I went for some sightseeing up the Montjuic, a hill between parts of Barcelona and the seaside. In the years back I noticed that while signal levels were quite high up there, data speeds were very slow and voice calls had very bad voice quality.

At the time I thought it was a temporary glitch by the network operator I was using. This year I had a bit more time to investigate. I was quite surprised, to say the least, that it wasn't a temporary glitch but it seems to be the normal state there. I tried with two network operators, both 2G and 3G, and while the signal level was strong, it was just noise. It seems the cells below "leak" up the hill and there is no decent dedicated coverage on top to ensure at least one noise free carrier. Make no mistake, this is a main tourist area!?

So go there for the view, it's magnificent but don't count on being reachable while enjoying the view.

Mobile World Congress 2010 Here I Come

Saturday morning, the suitcase is packed and I am ready to leave for Barcelona. Yes, MWC doesn't start until Monday and leaving early is intentional. Barcelona has a lot to offer and I am looking forward to do some sightseeing before the show starts. I've been in Barcelona many times but there's always something new to discover.

As every year I'll publish my thoughts on this blog throughout the week so stay tuned! After using various Nokia Nseries phones and a foldable keyboard for many years to report from the event, I've decided to take the netbook along this year. Weighing less than a kilogram I can easily carry it along. The bigger screen, more processing power and a full web browser make a huge difference when blogging.

If you are there and want to get in touch, please send me an e-mail (gsmumts at gmx dot de). You can also follow me on Twitter for the 140 character reporting 🙂 And yet another opportunity is to come by and see me at the Wiley booth (Hall 2, A100) on Wednesday between 2 and 4 pm, where I will host an author session to promote my latest book.

Viva Barcelona!

 

Internet Access on Thalys High Speed Trains – What Happened?

Back in June last year I wrote a post on my very positive experiences with the satellite based Internet access on board the Thayls high speed trains. Multi-megabit speeds, it was a joy to use it. Now, only a little bit more than half a year later the system is not much more than a shadow of its former self. During my past 4 trips, the system was down twice. And the other two times when it was available, speeds could be measured in bits per second and it was impossible to use it. What's going on Thalys? Have you reduced your overall bandwidth to reduce the monthly bill or has the service become so popular you are chocked by the demand? Either way, it's unusable and not worth paying for…

Oh and by the way, I thought long before writing this post but I couldn't let my very positive review stand on it's own, it just doesn't reflect reality anymore.

With VDSL, Wi-Fi Is Now The Bottleneck

Interesting to see how the bottleneck of my Internet connection at home has been shifting recently. With my new 25 MBit/s VDSL connection I am having difficulties shuffling peak data rates over my Wi-Fi network. So far with a 6 MBit/s ADSL connection that was no problem even for my notebook with a 802.11g adapter and a throughput of 21 MBit/s under the best of conditions.

For a 25 MBit/s downlink and 5 MBit/s uplink, however, that's not enough anymore. I've upgraded to 802.11n but even so I find it difficult to really squeeze the 25 MBit/s out of the wireless link. The 2.4 GHz band is quite crowded and the Wi-Fi access point is in another room so I don't get the signal conditions necessary for the highest transmission rates. I've tried the 5 GHz band that both the access point and the notebook support but the attenuation of the walls between my office and the router make the throughput even worse.

On the other hand, you first need to find a host on the Internet that delivers data at such high speed. In practice to really saturate the line several things need to go on in parallel. Not too difficult with kids using the connection, too I suppose…

Some GSM, UMTS and LTE Measurement Units

Even when a mobile device just sits there and seemingly doesn't doesn't do a whole lot it is nevertheless quite busy every now and then internally to check the signal strength and quality of the current cell and those around it to make sure it never looses contact to the network even if the user roams around. I've recently came across a good description of which values are actually measured in this book and thought I'd put together an ultra brief summary:

GSM

Here, the world is still quite simple. Once the mobile has found a cell it keeps monitoring it's received signal power and computes the Received Signal Strength Indicator (RSSI) over the complete carrier frequency (200 kHz). Neighboring cells use different frequencies and the same value is calculated for those as well.

UMTS

Here, things get a bit more complicated as all cells use the same frequency. As a result not only the received signal strength is important but also the general noise level on the carrier. In the end, what good does it do to you when the overall signal level is strong but most of it is interference? That's why there are three values: 

  • RSCP: The Received Signal Code Power: That's the power level the pilot channel of a cell is received with and usually expressed in dBm (mW on a logarithmic scale). With this parameter, different cells using the same carrier can be compared and handover or cell reselection decisions can be taken.
  • RSSI: In UMTS that's the signal power over the complete 5 MHz carrier which includes all components received, including the signals from the current and neighboring cells on the same frequency.
  • EcNo: That's the received energy per chip (Ec) of the pilot channel divided by the total noise power density (No). In other words the EcNo is the RSCP divided by the RSSI. And again in other words: The better this value the better can a signal of a cell be distinguished from the overall noise. The EcNo is usually expressed in dB as it's a relative value. The value is negative as the RSCP is smaller than the total received power. As the RSCP this value can be used to compare different cells on the same carrier and handover or cell reselection decisions can be taken.

LTE

LTE networks also use the same carrier frequency in neighboring cells so again the signal level and interference are important:

  • RSRP: That's the Received Power of the Reference Signal.
  • RSSI: That's the total received power including Interference from neighboring cells and other sources.
  • RSRQ: That's the Reference Signal Received Quality and equals the RSRP divided by the RSSI. The better this value the better can the signal of the cell be received against the interference generated by other cells.

Quite a lot of similarities between UMTS and LTE from a high level point of view even though the values are measured in quite a different way due to the different air interface natures (WCDMA vs. OFDMA).

A Strange Call – Skype and Mobile Handsfree

This is the strangest setup of a conference call I have been in for a while: A Skype video session with high quality audio over speakers and a third person, also on the other end, part of the conversation over a mobile phone as part of the call via loudspeaker/hands-free mode. The person on the other end of the line didn't even realize I was not in the room but a thousand kilometers away. On my end, the speech quality of the hands-free mode on the other end was also pretty much the same as if the phone was on my end. Speaks for Skype's audio codec and the echo cancellation of all devices.

GPRS Round Trip Delay Time Evolution

GPRS and EDGE might be far far away from current throughput speeds, but when looking more closely, it's evolution is also quite interesting and remarkable: When looking back 5 years or so, GPRS round trip delay times were around 900 ms for subsequent pings and 1200 ms for the first ping. Together with the relatively low overall speed, it took quite long for even small web pages to show up on my mobile device. Things have changed in the meantime, though:

These days, with EDGE data rates, one phase access, Extended TBF Uplink, continued TBF in downlink and pre-establishment of downlink resources when transferring something in the uplink, round trip delay times have come down to less than 200 ms for subsequent pings. In addition, I have noticed that in many networks, Network Assisted Cell Change (NACC) is now used for cell changes to minimize the interruption during cell updates when transferring data while being mobile. With OperaMini for example, that makes web access incredibly quick.

In retrospect, I am quite amazed how much these features have helped with the mobile browsing experience!

I’ll be at the Mobile World Congress 2010

It's already February again and as every year, I am very much looking forward to the Mobile World Congress in Barcelona. This year I think LTE and HSPA+ should be very high on the agenda of lots of companies there and I am looking forward how the hype around these topics will be in free flow 🙂

If you would like to meet me during the event there are several opportunities. On Wednesday, I'll be at the booth of Wiley, my publisher, between 2 and 4 in the afternoon (Hall 2, Booth # 2A100). So if you are interested in one of my books, in any other book published by Wiley for that matter, or just want to stop by for a chat, you are very welcome indeed. If you'd like to get in touch before the event you can also send an e-mail to gsmumts at gmx.de

I'm very much looking forward to the event and as usual, I'll do some live-blogging from the event.