Qualcomm downplays the importance of LTE in Europe

MOBILE CHIP DESIGNER Qualcomm has told The INQUIRER that LTE isn't necessarily the answer to the UK's mobile data woes in the immediate future. And what's more, it also warned that the quality of mobile phone calls could suffer when the system is introduced.

The issue, as Qualcomm sees it, is that LTE isn't quite ready for prime time yet, and that HSPA+ is a better bet for the next year or so. It also told us that it would like to see more phones and service providers pushing HSPA+ as soon as possible, which it claims will pay dividends in terms of efficiency and speed.

The biggest problem with LTE is how to handle voice traffic. Currently, with GSM and UTMS there's a complex system for handling voice calls. LTE should simplify that, but in order to do so it needs all voice calls to be delivered as packet data. This is unlike the current system, which uses circuit switching for voice traffic and handles data separately.

Qualcomm told us that the current plan in the UK is to use Voice Over LTE (VOLTE). That will, however, require a complete change in how mobile networks operate. Until now, voice calls have always been circuit switched, while data is, obviously, packet switched. The transition to a completely packet switched network will be expensive and take time.

So, in the meantime we'll be using a system that's like the one used by Verizon in the US, but slightly different. The main thing UK users will notice is that with early LTE implementations it won't be possible to have a data and voice connection simultaneously. To take a call, the phone will switch from the data radio over to the voice radio. On Verizon, handsets allow both data and voice at the same time, but can only achieve this with two radios working at the same time.

It's fair to say that using two radios all the time has a significant impact on battery life, and while it's undesirable to lose data connectivity while you talk, it should mean that LTE phones in the UK will have a little more stamina. But it's still a significantly worse situation than the one we have with 3G at the moment.

On the face of it, speed is an issue here. LTE promises greatly increased download and upload rates over UTMS 3G. But there is more to the mobile data experience than just speed. The time it takes for your phone to open a data connection is one area that LTE improves over HSPA, but HSPA+ addresses some of these problems too, and it's far easier to roll out than an entirely new 4G network. Indeed, in the UK Three has switched its network over and O2 is in the middle of doing so too.

Perhaps Qualcomm is right. It probably is more sensible for us to hold off LTE until mobile providers are ready to roll out voice over LTE rather than take a step backwards and use phones that can do either voice or data, but not both at any one time. µ