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A recent report I read about the future rivalery between HSPA and LTE has made me think about an important difference between the two technologies: Voice. While UMTS / HSPA intrinsically supports voice calls in the radio and core network, LTE requires the IP Multimedia Subsystem (IMS) for voice calls. So what will happen to LTE if IMS doesn’t take off? I know, many in the industry believe even asking such a question is close to heresy but who can promisse today that IMS will be a success?

The trouble with IMS and to some extent with mobile VoIP is not that it’s a young technology, standardization has been going on for many years and books about it are going into their third edition. However, there are still no IMS systems out there today that have come out of the trial phase, and I have yet to see a mobile device with an IMS client which is nicely integrated and simply works. Also, the IMS standard is getting more complicated by the day which doesn’t make life easier. Another main issue with VoIP and consequently IMS is power consumption. I use VoIP over Wifi a lot on my Nokia N95 and can nicely observe how the phone slightly heats up during a long phone call. Also the non-IMS but SIP compliant Nokia VoIP client in the phone, which by the way is nicely integrated, sends keep alive messages to the SIP server in the network several times a minute. This is necessary mainly due to Network Address Translation (NAT). While this doesn’t require a lot of power over Wifi, power consumption skyrockets as soon as I configure VoIP for use over 3G. I can almost watch the power level of the battery drop as the network now constantly keeps a communication channel open to the device. So there are two problems here: VoIP calls cause a much higher processor load during a call, i.e. the VoIP talk time is much shorter than the 2G or 3G talk time and the standby time is significantly reduced. Add to that the missing handover capability to 2G and 3G networks (yes, I know there is VCC in theory) and you have a prefect package for a very bad user experience.

So the big question is if all of these things can be fixed, say over the next 5 years!? I have my doubts…

If not, then LTE has a big problem. Will network operators accept running GSM or HSPA alongside LTE until the problems are fixed? The choice is this and accepting that LTE is for Internet access and some niche VoIP applications on devices such as notebooks or to decide sticking to HSPA(+) until things are fixed.

In case LTE is deployed and LTE – IMS devices are not ready it’s likely that a device can’t be attached to several radio networks simultaneously. So how do you inform a device attached to LTE about an incoming voice call? It looks like the people in standards bodies are looking at different solutions:

– Send a paging message for an incoming circuit switched voice call via LTE to the device. You can do this on the IP layer or on the radio network signalling layer. The device them switches radio technologies and accepts the call.

– Some people have started thinking about extending LTE with a circuit switching emulation. This could be handled on the lower layers of the protocol stack and the software on top would not notice if the call uses GSM, UMTS or LTE. This one is easier said than done because I don’t think this concept will fly without a seamless handover to a 2G or 3G network. If such a solution ever gets into mobile phones, it would make life for IMS even harder. Who would need it then?

Are there any other initiatives I have missed so far to fix the LTE voice issue?

This week I am probably the fastest Carnival of the Mobilists reader, as I was traveling  at 300+ km/h with the high speed train from Avignon to Paris while reading the posts on my Nokia N95 with OperaMini. The carnival this week is about as fast paced as was that train, so make sure to check it out at the Vision Mobile Blog. There’s definitely no better place to find out what happend in the mobile space in the previous seven days. Enjoy!

I’ve observed my network usage over the past couple of days to see how much data I would transmit and receive over the course of a week while traveling. I’ve noted that there is a big difference between PC and mobile device use in terms of uplink/downlink ratio. With the PC, which I mostly use to access my eMail and for web based services, the ratio is about 10:1. The ratio on my N95, however, is close to 1:1 as I upload pictures, blog posts and eMails. Especially picture uploading with Shozu has a major impact on the ratio.

Other statistics say that 90% of the data traffic in mobile networks is from PC’s and I think that also reflects my behavior. As a consequence, the uplink traffic generated by mobile devices is still an order of a magnitude smaller compared to overall downlink data traffic.

With faster uplink speeds becoming available the ratio could change once it becomes feasible to upload high quality video material from mobile devices in a reasonable time. That’s about the only application I can imagine that could have a real impact on uplink use. Until then, however, the uplink will remain rather unused.

Recent news that Nokia would buy Symbian and put it together with its own S60 user interface into the new Symbian Foundation has sparked quite some interest. One reason for this move is that the operating system and the user interface is more and more seen as a platform which is better to distribute to as many players as possible than to use it as a differentiator. Differentiation should come from the applications running on the platform.

Recently, due to a one day outage of ProfiMail on my N95, I became aware of just how dependant I have become on my N95 from software that is not directly from Nokia, i.e. that didn’t come in the box when I bought the device. Together with OperaMini, Profimail are the main applications I use on my mobile device. Should both companies decide to leave the business (o.k. very unlikely but just imagine for a moment) I would be without a real alternative since both programs communicate with the mothership in order to function.

Sure, there are other browsers and other eMail clients but these two are definitely unique and I couldn’t replace them easily with others for my purposes. On the one hand this is good news for Nokia since third party programs have become a strong pillar in the overall value chain and thus promote the versatility of their platform. But on the other hand there is also a certain vulnerability as their own products are not where the competition is in a number of important areas, at least for my purposes.

I was a bit sad over the weekend when I cleaned out my my RSS feeds as about half the blogs I’ve been reading over the past year have gone quiet. Hope you guys are coming back at some point. On the positive side other people are setting up new blogs to post to the world. And the best place to find both long timers and newcommers is the Carnival of the Mobilists, a compilation of the best writing around mobile of the past week. This week, the Carnival has stopped at the Mippin Blog. So head over and enjoy!

For those of you interested in what’s going on with the Symbian Foundation, I think the following links might be of interest:

The History:

• Psion – the last computer: An account of the company that created Symbian by Andrew Orlowski at the Register

The Future:

• David Wood (EVP of Research at Symbian) has started a new blog to share his thoughts on the transition of going Open Source with the Symbian Foundation

• John Forsyth’s (Symbian VP for strategy) blog on the same topic from his point of view

Great opportunities to take a look behind the scenes with some of the people who will shape the future of Symbian. This is how company blogs should be!

Thanks to Michael Mace over at Mobile Opportunity for the pointers!

Many people say many things about what the iPhone changes in the wireless world. But this one I haven’t heard about before: Looks like the introduction of the iPhone in Canada has made Canadians becoming aware of the high prices they have to pay for mobile Internet access compared to in other countries. When I checked a year ago, I had difficulties to even find a data plan on Roger’s web page. Looks like things have changed at least a bit since then, they are now offering packages from a couple of hundred megabytes to a couple of gigabytes, but still at rates several times higher than what you have to pay for the same package in Europe. Interesting links on the topic here, here and here. And for Roger’s price plans take a look here. What I don’t see at all yet are promotions for Internet access via 3G/USB sticks for notebooks which has become very popular in many European countries lately. One step at a time I guess…

In the past I have reported that my Nokia N95 had the nasty habbit of rebooting spontaneously while using OperaMini and moving from cell to cell e.g. while traveling on the train and in the metro. How often the mobile rebooted semt to depend on the country, i.e. which mobile network I used, i.e. which network vendor supplied the infrastructure. This week I noticed that my N95 no longer reboots in the metro. That is interesting, since I haven’t made a software update and the Opera Mini version is still the same. So it seems like the network operator, Orange France in this case, must have made a software upgrade in the network or has changed some parameters. In any case, mobile Internet use has become much more practical again for me in France. Thanks to whoever fixed it.

Another week, another Carnival of the Mobilists. It’s my great pleasure to point you to Andrew Grill’s blog where you can find the latest edition of the Carnival of the Mobilists which has the latest on what has happened in the blog space on everything mobile in the past week. So don’t hesitate and head over and enjoy.

A lot has been written lately about Nokia buying the Symbian shares of Sony-Ericsson and others and creating the Symbian Foundation to release the OS as open source in the future. A lot of people become ecstatic when they hear  ‘Open Source’ as it seems to be a synonym for success and the only way to go. However, there are different kinds of open source approaches and usage licenses so it is worth to consider what developers will be able to do with Open Symbian that they can’t do today.

I think the big difference to Linux, which is also open source and has attracted many individuals and companies to start their own distribution, is that I think it is unlikely the same will happen with Open Symbian in the mobile space. In the PC world, the hardware is well standardized so people can easily modify the kernel and compile and run it on their machine. In the mobile world however, hardware is very proprietary so I think it is unlikely that the same will happen here, no matter how open the Symbian OS becomes. Therefore, an open Symbian is mainly interesting for hardware manufacturers as they will have easier access to the OS and can customize it more easily to their hardware. That’s a long way from ‘I don’t like the current OS distribution on my mobile so I download a different one from the Internet and install it on my phone’. But maybe we are lucky and open sourcing the OS will allow application programmers to use the OS more effectively and extend it in ways not possbile today due to the lack of transparency.

For more thoughts on what the Symbian Foundation might or might not change in practice, head over to Michael Mace and AllAboutSymbian, they’ve got a great insights on their blogs from a lot of different angles.