Author: Martin

… asks Ajit Jaokar over at OpenGardens in a recent blog entry. The post is a great collection of thoughts of why the spectrum crunch, so often cited these days to be happening in the US might actually be a myth. I would even go so far as to argue that there is no bandwidth crunch at all. About a year ago, I've been comparing the amount of spectrum available to US carriers and the amount of spectrum available in Europe. For the details see here. In summary, the amount of spectrum available on both sides of the Atlantic is about the same but we certainly don't suffer from any bandwidth crunch over here in Europe, we are actually far from it in networks that are well dimensioned. Here's an example. So whatever the reasons are for slow networks in the US it's not a lack of spectrum. For additional background reading, here are two interesting posts from Dean Bubley on the topic, flattening data growth and O2 UK's data usage patterns.

It looks like Wi-Fi hotspots remain a significant weakness in the overall security landscape. A year ago Firesheep was released and showed how easy it is with a notebook to spy on other users of non-encrypted public Wi-Fi networks and even use the stolen session credentials to do things like sending Tweets and Facebook messages. Some companies have reacted in the meantime by introducing or expanding the use of secure HTTPS sessions to protect their users but many services such as LinkedIn, eBay and others remain vulnerable to some degree to this day.

But security researchers haven't stopped there. Now, Firesheep has moved on to mobile devices in the scape of DroidSheep. All that's required is a rooted Android phone and the network is literally in the hands of an attacker. DroidSheep goes one step further than Firesheep and even has an ARP spoofing functionality so all traffic of the Wi-Fi hotspot is redirected to the mobile device before it traverses the router to the Internet. This allows spying on others even in encrypted networks (if the WPA password is known of course) which otherwise prevents Firesheep and Droidsheep from working due to individual session keys generated from the single password everyone uses.

To see what Droidsheep can do I tested it out myself in a private test network at home. Without much effort the program worked as advertised and it showed pretty much every site I was going to which was not using https. To my great astonishment I saw that the Facebook mobile app running on another Android device communicated with Facebook servers without any encryption! With Droidsheep I could take over the account in seconds and could write to the wall and do other things with the Facebook account I was using on my other device. In the settings, the app even admits that encryption is currently not supported as shown in the picture on the left.

For Wi-Fi hotspots to become an integral part of a cellular network offload strategy, these security issues have to be tackled. The solution that comes to my mind is to automatically start a VPN once a Wi-Fi hotspot is used and prevent any user traffic to be transferred while the VPN is not in place or has dropped due to an attack that takes down the VPN tunnel. Above all, the use of the VPN, blocking unencrypted data traffic and restarting the VPN must be fully automatic so it is fully transparent to the user. Otherwise it won't find widespread acceptance and use.

Currently there are only three network operators in France but the launch of the fourth network operator ‘Free’ is imminent. Perhaps Free will be the last startup mobile network operator to launch in Europe with a network from scratch for the next decades as the trend in most other European countries is for network operators to merge. As Free is definitely all but an incumbent mobile network operator and had a significant impact on the French DSL market with its low prices and new services it is going to be interesting to see what kind of strategy they will be using to win over customers from other network operators. Just doing the same but a bit cheaper might not do the trick and it would be very much unlike the fixed net ‘Free’.

So here’s my wish list and thoughts of what they could do differently, keeping in mind the following resources that they have at their disposal:

• 5 MHz of UMTS spectrum in the 2.1 GHz range

• No GSM spectrum for the moment, but they do have a roaming agreement for 2G and 3G with Orange. They'll get 5 MHz in the 900 MHz band starting 2013, however, and that's not that far away. For details see the French Wikipedia entry on UMTS.

• 20 MHz of LTE spectrum in 2.6 GHz

• No LTE 800 MHz spectrum, but the right to use SFR as a host network for LTE in the 800 MHz band for deep indoor and rural coverage.

The Prepaid Voice and SMS Market

The first thing that comes to mind is the voice and SMS prepaid market in France, which, compared to other countries in Europe is totally underdeveloped. Prepaid prices are sky high with per minute charges ranging anywhere between 25 to 50 cents. Compare that to the 6.8 cents a minute in Austria or 8 to 9 cents a minute in Germany. Another really annoying thing is the credit validity time. Even a 35 Euro recharge extends the validity time by only three months. In other words, even on prepaid, a subscriber has to spend a minimum of 12.5 Euros a month or loose all credit still on the SIM card after three months. Prehaps Free can be different?

The Prepaid Mobile Internet Market

Free grew up in the French DSL market so their pitch to get to the customer was to offer high speed Internet access with a voice telephony flatrate to fixed line destinations put on top (replacing the POTS telephone of France Telecom). While the arrival of the iPhone and the iPad has triggered the emergence of prepaid data SIMs in France it’s by no means as cheap and ubiquitously available as in other countries, i.e. you pick up a SIM in a supermarket and start using it. Another untapped opportunity in France and I’d be one of the first customers picking up one of their prepaid data SIMs for my netbook and occasional visits in France in a French supermarket if prices in combination with the amount of data would be acceptable. Here’s a hint: In Germany you can buy prepaid SIM cards for Internet access for 3 euros a day with a limit of 1 GB, 10 euros a month for 500 MB or 20 euros for 5GB. And compared to Austrian prices that’s not even particularly cheap.

Free’s LTE Strategy

It’s going to be interesting to observe what Free will do with their LTE spectrum in the 2.6 GHz range. For launching their service, the 5 MHz slot in the 2.1 GHZ range for UMTS will suffice to offer good service for a while. But should customers decide to go for Free, a single 5 MHz channel won’t last for long, and most network operators have reacted in the meantime and are now using at least two 5 MHz channels in cities. Free will be able to do that too starting from 2013 as they will get a 5 MHz channel in the 900 MHz band. Here, they have an advantage over the incumbents as they can use it for UTMS straight away instead of going for GSM first, or having to free the channel of GSM first. The incumbents can use HSPA+ dual carrier in the 2.1 GHz band though, which gives them an advantage when it comes to maximum transmission speeds per user. So Free might be a bit releaxed when it comes to LTE. Once they want to go for it, however, it might be easier than launching their UMTS network in the first place since they have their 3G equipment in place now so they don’t have to find any additional sites, which is the main overhead in terms of costs and delay. Their equipment is likely to be multi-RAT capable so adding some more processing capacity and an additional radio module for the 2.6 GHz band will likely do the trick. If they were smart, the antennas installed over the past months are already 900 MHz and 2.6 GHz capable, making hardware modifications on top of a mast unnecessary. That would be quite an advantage to the other incumbent network operators who likely have to retrofit their base station sites with new antennas and perhaps also new base stations, or put additional LTE base stations next to their installed equipment. Actually it might even be a good idea to start with LTE as quickly as possible and sell 3G/LTE USB dongles as soon as possible so they can move the heavy users with notebooks and netbooks to LTE as soon as possible to reduce the load on their UMTS network to keep the quality of experience for their smartphone users.

IMS, Even Trickier With National Roaming

So what about voice over LTE? Here, Free is in a more difficult position than the already difficult situation incumbent mobile network operators are in. CS fallback is even more tricky because of national roaming. Falling back to your own network is already no fun and increases call setup time. Falling back to a network of a competitor due to the use of national roaming would be even more tricky. National roaming would also make VoLTE with handover to a circuit switched GSM channel (Single Radio Voice Call Continuity, SRVCC) to a competing network a huge challenge because two core networks of two companies would be involved. So I think both are not even a remote option for Free in the short and mid-term and if I were them I’d use LTE for Internet access, except perhaps for devices such as routers without mobility, where no fallback to a 2G or 3G network is required.

Femtocells

This could be an interesting one for Free. There are indications Free might include femto capabilities in their DSL home equipment. Depending on the take up, that could also reduce the load on their macro network as phone calls made at home would use the femto rather than their macro network by those customers who also use Free for their home Internet access. With attractive pricing of calls made via the femto at home they could perhaps make other people in the family switch to them as well.

Summary

Free has an impressive record in France when it comes to the disruption of the fixed DSL and cable marketing France. The wireless domain in France offers interesting opportunities already used in other countries in Europe that are waiting to being picked up. Also, their brand new access network should make it quite simple for Free to launch LTE services quickly to reduce the load on their limited UMTS spectrum. I suspect it won’t be long now and we’ll see first offers.

Just before Christmas 2011, the French regulator ARCEP announced the result of the auction of the 2×30 MHz spectrum in the 800 MHz digital dividend band. All three incumbents, Orange, SFR and Bouygues each won 2×10 MHz. Free has been unsuccessful to get spectrum directly but SFR is mandated by the spectrum auction terms and conditions to cooperate with Free, (probably) because they have won the 10 MHz that are in the middle of the frequency range.

Unfortunately, the press release does not quite reveal why it is SFR that is specifically required to share their spectrum with Free!? Also, the the 1 billion SFR paid for the middle section is 320 million more than what Bouygues had to pay for the lower section and still another 120 million higher than what Orange had to pay for the high part of the spectrum. Each of them still have 10 MHz. So I am not quite sure why the middle part is the most valuable part of the band. I could imagine that the lower part might imply some more coordination efforts with terrestrial TV transmissions which use the frequency range just below. But the higher part is unaffected by this so why is SFR required to share the network with Free and not Orange? The press release doesn't go into those details so if you know, please leave a comment, I'd be quite interested in this.

Other interesting bits and pieces mentioned in the press release:

• All three network operators have committed to allow "full" Mobile Virtual Network Operators (MVNOs) in their network. It's not quite clear to me how "full" MVNOs are defined but let's hope it will encourage more competition and thus better prices and conditions for customers in the future compared to the very closed and non-competitive French wireless market compared to other countries in Europe today.

• There are similar requirements as in Germany to ensure the 800 MHz spectrum is first used in rural areas to bring Internet connectivity to under-served areas. From the press release: "[the network operators] must commit to an accelerated rollout schedule in the most sparsely populated parts of the country".

One of the things I have observed in the past when offering Internet access at meetings is that ISPs return IP addresses of DNS servers which are only slowly or unreliably answer DNS requests. This is why by default I don't go to these anymore but use Google's own DNS servers reachable via the easily memorizable IP address 8.8.8.8. This IP address is reachable in all parts of the world I've been so far with only minimal latency.

Recently, however, when I was on the Philippines, I noticed that while the Google DNS server responded to ping requests, there were no answers to DNS requests. As the issue continued over a number of days it seems that either the outgoing DNS requests were blocked or incoming DNS responses were discarded before reaching me. I did a search on the web to see if there is any information whether the Philippines block foreign DNS servers but came up empty handed. If you know more, please let me know, that would be quite interesting.

I've been on the Philippines recently for a round of meetings and it was interesting to observe the availability of bandwidth for non-secure and VPN encrypted traffic to oversea destinations.

During the later parts of the evening, at night and during the morning, I could easily transfer 2-3 MBit/s a second over my VPN connection. If I dropped the VPN connection and went to the same overseas websites directly and downloaded email (still encrypted over secure POP3 and secure SMTP), speeds were in the same region. During the day however, speeds over the VPN connection dropped to 200 to 300 kbit/s while unencrypted access to web resources in Europe and the US remained above the 1 MBit/s level. The difference remained even when I changed the VPN transport type from UDP packets to TCP packets terminating at the https port 443.

The same effect could be seen no matter whether I used the hotel Wi-Fi or the 3G network via a local SIM card. That likely means that it's the overseas link that becomes congested during the day. Just strange that encrypted connections were more affected by it than plain http traffic. Also, it didn't matter whether the VPN tunnel ended in the United States or in Europe, throughput levels were equally low during business hours.

I wonder if all that means there is a special preference for certain types of traffic for oversea links!? It was also interesting to observe that my company VPN, which works with a different technology than my private VPN based on OpenVPN was throttled down even further during the day time to 100 kbit/s and sometimes even less. Other participants at the meeting noticed the same behavior which is a bit of an annoyance if everyone depends on new versions of documents stored on a server abroad.

To overcome this limitation I mirrored some documents for the meeting on a local server on the IP subnet the Wi-Fi access point supplied. Unfortunately, not all participants could access local resources as many company firewalls and VPNs prevent devices to access local resources.

An interesting reverse strategy happening at the moment on my smartphone:

Instead of having Wi-Fi activated on my smartphone by default to benefit from cheap internet access at home and access to local resources I am rather opting now to have it switched-off by default unless I really need it, e.g. to download podcasts, videos etc.

Why? Because my current smartphone's Wi-Fi reception is quite restricted and I've experienced a couple of times that while it could still see the Wi-Fi access point it had difficulties to transfer data due to the reception level. Instead of switching to the cellular network, however, it got stuck. Not good, this is not yet implemented well. Also, I usually don't use any local resources such as a NAS server with my smartphone and I also don't use it as a remote control for any gadgets residing in the home network. I travel too much so my home network is rather basic compared to others.

When comparing the reception quality of smartphone with larger devices such as notebooks it seems that it is in general much weaker. While my notebook sized devices still receive the Wi-Fi network very well in remote corners in my apartment, mobile devices already have difficulties. So unless that changes and I have an all-you-can-eat 3G data package anyway and don't hit the throttling limit, my smartphone Wi-Fi will stay off at home.

What about you, do you use Wi-Fi at home and what are your experiences concerning reception and range?

Nokia's recently produced a couple of Dual-SIM phones which I haven't seen around much in Europe. When visiting the Philippines, however, I could observe them being marketed by the local Nokia stores alongside pretty much anything else in the Nokia portfolio, including the Nokia N9 and, as a major absentee, the Nokia Lumia.

While observing the people in a park in Makati, Manila's business district, I noticed that quite a number of people had at least two phones with them, some of them even three. When asking why, I was told that most people use on-net "all you can eat" packages while voice calls and SMS messages are rather expensive. So it seems to be cheaper to get a couple of prepaid SIMs from different networks and extra phones rather than to pay for inter-operator charges. So for people with a quite restrictive budget, a Nokia Dual-SIM phone probably makes a lot of sense.

People in the Makati district, however, probably have a significantly higher income than the average consumer in the country and I could observe that one of the two phones was usually a smartphone while the other was a what many people a low end phone. The smartphone was usually either an iPhone or a high end Samsung or HTC Android based device. I failed to see anyone using a Nokia smartphone.

… asks David Talbot in a recent article on the Technology Review website. An interesting question and I'd really like to see a solution that shows who receives what kind of information from apps or the operating system itself that is originally shipped with the device.

But not through a cloud of fine print as is often the case today but detailed and to the point please. With a number of discoveries over the past few months of location information and private data being harvested and sent off mobile devices lately without users being aware of the fact, I think it is really time for this. Also I think it would be a good idea to put some law behind this to ensure that there are consequences if the devices does more than actually described in such a list.

Obviously such a feature would have a difficult time to track what kind of data third party applications send out but I think the point of such a feature would be to ensure that the user knows what he gets at the time he buys the device. Anything installed from a third party later on is his own responsibility. And Android, for example, makes it quite clear what kind of capabilities an app requests during installation and it doesn't take much imagination what an app can do when it requests Internet connectivity and access to calendar and address book.

3GPP standardization is well ahead of real life deployments and it has to be, as developing and testing the ever more complicated features takes time. Currently, Release 8 of the specifications has made it into the real world, with HSPA+ Dual Carrier deployments and first LTE networks now in commercial use. So from a radio access, speed and capacity point of view, what's in store between this and what will Release 11, that is currently under development, put on top of it?

A detailed resource listing the new features of each Release can be found here. If you have a look you'll immediately see that my list below is but a tiny fraction of what has been done in each release. My focus for this post, however, is very narrow and only looks at how the capacity of the macro base stations is enhanced as we go forward.

In Release 9, HSDPA gets enhanced by adding MIMO to Release 8's combination of Dual Carrier + 64-QAM, pushing theoretical peek data rates from 42.2 MBit/s to 84.4 MBit/s. To make things more flexible, the two 5 MHz carriers can now be in different frequency bands. In the uplink direction, dual carrier operation is introduced (while having been present in the downlink since Release 8), thus pushing theoretical uplink data rates beyond 20 MBit/s.

With Release 10, 3 and 4-carrier HSDPA is specified in up to two different frequency bands. Like the already existing dual-carrier feature, aggregating carriers has little impact on overall capacity of the network but offers higher peak data rates to individual users. On the LTE side, carrier aggregation beyond the initial 20 MHz is introduced and the number of antennas for MIMO in the downlink direction is increased from 4 to 8. Again, this is well beyond what is used in life networks today with up to two independent streams in the case of LTE. In the uplink direction, up to 4 antennas are now specified to increase data rates under ideal conditions.

From a raw maximum throughput point of view it seems that a limit has been reached. It is unlikely anything more than 64-QAM modulation makes sense and 8 MIMO data streams will keep engineers busy for a long time to figure out how to put such a high number of antennas on roof tops and crammed into small devices.

But ultra high data rates are not everything when it comes to overall maco network capacity. A major issue is interference between cells, especially for users that are at a location where they get a strong signal from more than one cell. Here, higher order modulation and MIMO is not much help.

Therefore, one of the major topics in 3GPP Release 11 in this respect is Coordinated Multi-Point (CoMP) transmission. Nomor's current LTE newsletter shows this quite clearly by giving an overview of currently active work items in the different RAN working groups.

Here's an abbreviated list of the objectives of CoMP from the current version of the work item description (RP-111117):

• Specify the support of intra- and inter-cell CoMP
• Joint transmission
• Coordinated scheduling/beamforming

And, in case that has sparked your interest, further details can be found in the study item 3GPP TR 36.819 that preceded the current work item.

Coming back to the title of the post "the air is getting thin", it's interesting to observe that after years of specifying how to get ever faster data rates, significant work is now done around improving data rates in places far away from a good signal. Not only will this help individual users to get a higher data rate in such places, but network capacity in general is increased by spending less time transmitting and repeating lost data slowly with a very low modulation and coding scheme. It will take a few years before we see this in practice but I think chances are high that the result of this work item will see the light of day.