MWC – WirelessMoves

MWC – Connectivity in Barca – Sometimes Even Plan C Fails

I arrived in Barcelona yesterday for the Mobile World Congress which does not start until next Monday (or Sunday, depending whether you count the pre-congress parties or not…) but it's nice to be here a couple of days early to relax a bit. I am usually used to just replace my SIM card with a local one or at least with one that has acceptable roaming rates and get connected in a couple of minutes. What I experienced yesterday, however, reminds me of days that I thought were long gone.

After having arrived at the airport I replaced my French SIM with one from German MVNO "Medion – Alditalk" to check my e-mails on the mobile before I could top up my local SIM card or buy a new one after baggage claim. Unfortunately, while the SIM card booked into the circuit switched part of two networks o.k., I could not get a data connection on the packet switched side (GPRS attach fail). O.k. Medion – Alditalk is not really known for their stable network operation so I moved to plan B.

From last year I still have two local SIM cards from Yoigo. One was not working anymore, while the other still booked into the network (both CS and PS attach ok). No idea why one is still activated and the other is not!? Anyway, so I went to the next store at the airport to put some money on it again (the balance was at zero since they deduct 6 euros per month if not used). Unfortunately I had to find out that you have to know the phone number to top up. Eh, sorry, can't remember, I am used to scratch card top ups…

All right, time for plan C, by now already at the hotel. My German Vodafone SIM card with the Websession option gives me 50 MB of traffic for 15 euros / 24h while roaming. While it worked fine on the Vodafone Spain 2G network, my N95 refused to work on their 3G network (PS attach ok, PDP context activation ok, but only spurious ping replies). Network/mobile incompatibility? Hm, so I put the SIM card in my E220 3G USB dongle but the effect was still the same. So either the 3G cell near the hotel is having problems or there is a more serious problem up the line.

So plan D for the moment is to use the Vodafone SIM on the slow GPRS network for mobile use and the crappy hotel Wi-Fi for the notebook. In the meantime the Medion – Alditalk SIM is booking into the GPRS network of Orange again, so I could now also use that.

Well, I guess that was not really my connectivity day… Let's hope things work out better today. All this and the 50.000 people coming to the congress haven't even started yet to put load on the networks in Barcelona.

Current LTE Mobile Device Form Factor

Last year, LTE mobile devices where still the of the size of a cabinet. At this year’s 3GSM / Mobile World Congress the hardware has now shrunken to the size of a PC motherboard. The picture on the left shows a LTE mobile with 2×2 MIMO from LTE which was used to stream several videos at a speed of 30+ MBit/s via a LTE prototype base station supplied by Nortel. So by next year we should see first PC-card prototypes. Things are moving ahead.

The 3GSM Gem in Barcelona: Intel and Motorola’s Live WiMAX network

I had to hold back with this blog entry a bit because I wanted to get permission first to write about what I would say was the most interesting demo I’ve been invited to during the 3GSM / Mobile World Congress:

Lots of WiMAX demos where shown at this years congress and it’s good to see that 802.16e mobile devices have now reached PC-card card sizes and are close to general availability. It’s also nice to see that when the antenna is just a couple of meters away you can see data rates beyond 10 MBit/s. However, that tells you only little about how the system performs in practice when the base station antenna is a couple of blocks away on top of a building and there is interference from neighboring base stations. To go the extra step, Intel and Motorola have teamed up to show how their kit works in a real environment during this years show.

Network Setup

In just a few days, Intel has put up four Motorola WiMAX base stations on rooftops in central Barcelona which were connected to the core network via 50 MBit/s microwave backhaul equipment from Dragonwave. Each base station was equipped with 3 sectors, each on its own 10 MHz channel in the 2.5 GHz band. In total they had three channels available for the network so each base station used the same set of frequencies. The distance between the base stations was about 2 kilometers which is a bit more then what you would see in an inner city network deployment. They couldn’t choose the sites themselves and had to be happy with what they got. On the upside, there is less interference from neighboring cells then there would be in a public network since there were only 4 cells and thus there is no interference from cells further away.

Indoor Experience

Sitting comfortably in the lobby of a hotel in Central Barcelona, I first had a chat with the technical project manager responsible for the network setup. Very good to have somebody with a technical background to talk to. During our discussion I got a first impression of the network performance as there were two notebooks connected to the network, one via a WiMAX PC-card adapter and the other via a CPE (Customer Premises Equipment) box the size of a DSL or cable modem. Despite sitting in the ground floor lobby, the base station being a couple of rooftops away on the other side of the hotel, the probably heat insulated and RF absorbing windows and just using the built in antennas of the devices we still got a data rate exceeding 2 MBit/s via both the CPE and the PC-card adapter. Note that both were SISO (Single Input Single Output) devices. As even this speed is far beyond what you can make use of while surfing the web we streamed a couple of video streams being sent live from WiMAX connected vehicles touring the city. The resolution of the stream was around 320×240 pixels and with a frame rate of 30 fps and the video streams were crisp and clear. One of the notebooks also had an engineering monitor software package on it to observe lower layer performance of the PC card and it was interesting to see how the card goes through the different modulation and coding schemes from QPSK to 64-QAM as reception conditions changed.

Outdoor Experience

Later on we went outside and used Segways to speed up and down the streets with a notebook attached to it to see how the network copes with mobility. Again the video stream performance was flawless and we streamed a U.S. TV station over the Internet which is quite bandwidth hungry. But even this does not require a bandwidth beyond 5 MBit/s which was obviously not the limit of the network. When asked what the highest throughput is that can be observed in the network I was told that it is around 13 MBit/s with 64-QAM and about 1.5 MBit/s at the cell edge with QPSK ½ modulation and coding despite the fact that the cells are too far away from each other. Interesting numbers showing the direction in which we are headed once 2×2 MIMO is added and proper cell sizes are used.

Here’s a video taken and produced by Marc Wallis and Michael Ambjorn of Intel/Motorola respectively:

(copyright by M. Wallis / M. Ambjorn of Intel/Motorola)

Conclusion

I came away very impressed from the demo as the speeds were amazing. We didn’t loose the connection to the network even once during the one and a half hours sitting in the hotel and touring the city. That says a lot about the software stability of the PC-card and the network. Thanks a lot to Intel for the VIP tour invitation it was definitely the best demo I have seen during the Congress.

Mobile Jam Session the latest addition to the 3GSM side event Wiki

Three weeks to the 3GSM / MobileWorldCongress and the side events Wiki starts to fill up! The Mobile Jam Session for developers is one of the latest the latest additions. Conceived by Rudy de Waele and Caroline Lewko the half day event is geared towards developers in the mobile space. Instead of passive participation the concept forsees active partcipations by all attendees. I imagine it will be highly ad-hoc and inspiring. I am looking forward to it very much. For details and registration head over to their web page.

For other events, get togethers and parties see the 3GSM Side Event Wiki. All pages can be edited by anyone. So if you hear of something interesting, you can easily and quickly add it to the pages.