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Networks under smartphone stress

Mobile networks are suffering from smartphone stress. E&T finds out who's to blame, and what can be done about it.

When Apple introduced the iPhone in 2007 it reshaped the mobile landscape almost overnight. Suddenly, consumers were clamouring for a phone that made the Internet usable on the move - despite the fact it wasn't that good as a phone. As the user base grew, complaints started rolling in about battery life and then network performance - two factors that have now become opposing forces in the tug of war that defines how smartphones interact with the mobile network.

Demanding demand

The statistics for mobile Internet growth are dramatic. Paul Jacobs, chairman and CEO of Qualcomm, said at the company's recent Uplinq conference: 'The total bits consumed for data traffic now exceed those used for voice worldwide. Some analysts predict that by 2014 we will use as much data in a month as we did in the whole year of 2008. But there is only so much spectrum to go around.'

Speaking at the recent Future World Symposium organised by the UK's National Microelectronics Institute, O2 vice president of research and development Mike Short said: 'The number of Facebook users accessing the service by mobile has overtaken those using fixed-line connections.

'We have sold large numbers of iPhones. The video downloads are enormous and have put strains on our networks. We have to be careful how we deliver these richer graphics and video content.'

Erol Hepsaydir, director of radio solution strategy at Hutchison 3G, agrees: 'We are looking at how we can improve performance, particularly on mobile broadband. Traffic on the network is growing significantly, especially after HSDPA was deployed. Some 40 per cent of our mobile broadband traffic is from YouTube. During the busy hours of 8pm to 12am, we see an impact on the customer experience. They see quality degradations coming from network capacity.

'All parts of the network have a certain amount of capacity. We can put in capital funding but when it comes to the spectrum, we have limited spectrum. It's a solid limit: we can't have more than 15MHz. That's our licence. So, our capacity limitations are shifting towards spectrum.'

Running to stand still

The shift to Long-Term Evolution (LTE) will improve spectrum efficiency. Short says trials by O2 in Slough have demonstrated data rates of up to 50Mbit/s. But Hepsaydir says the improvement may be eaten up by video enhancements such as high-definition TV on mobiles.

'Video is heavy; high-quality video is even heavier,' says Bjorn Ekelund, head of ecosystems and research at ST-Ericsson.

Video dominates the bandwidth requirements of smartphones when they access the Internet. But there are two other, more insidious ways in which mobile devices affect the mobile infrastructure. They stretch the signalling system that keeps the network going far more than anyone had expected. And application developers see no problem with using the networks to poll servers every 30 seconds in the hope of finding new social data, often coming away - a hundred packets and a lot of network signalling later - empty-handed.

'We are expecting many new services to flourish. As we look to 2020, we have forecasts of something like 20 billion Internet-capable devices,' says Short. Attention is falling on how those devices interact with the network because the growth in the number of devices served threatens to outstrip network operators' ability to cope. 'We have the danger of digital brownouts happening where the supply of bits doesn't meet demand,' says Jacobs. Although one option is to upgrade the technology, the Qualcomm CEO told developers at the conference: 'You have the responsibility of building applications that are as efficient as possible.'

Today, developers of mobile applications and operating systems pay more attention to the battery life of the handset than the health of the network (see 'Extraneous signals', opposite). On top of that, few apps cache data on the handset, going back to the server to get large files and datastreams retransmitted when they are reactivated.

These issues have convinced technology suppliers such as Alcatel-Lucent, Qualcomm and NSN that more needs to be done to educate the operating-system and app authors on the effects that their products have on the wider network. 'When checking for data every 30 seconds, they don't understand what effect they have on the network,' says Leslie Shannon, mobile-broadband marketing manager at Nokia-Siemens Networks.

Aligning interests

Companies have set up centres to try to bring the different parties together. For example, NSN has established Smart Labs in Finland and the US to look at how different applications and devices work with the mobile network as well as to extend the range of services they could offer. Alcatel Lucent has started on a strategy to try to align the needs of applications developers, operators and equipment makers.

'We are going through a transformation of the way that networks are used,' says Houston Spencer, head of customer solutions marketing for northern Europe at Alcatel Lucent. 'We have just embraced an acknowledgement that there is a big need for the telecom business model to change. The basics of that are fairly well known. 'All you can eat' broadband at a declining price just doesn't work if people's stomachs get bigger.

'The broadband appetite is increasing while the price is reducing. We are convinced that a new business model will emerge. We are keen that that comes quickly and proactively. I would rather see a proactive transformation than a forced evolution.'

Alcatel Lucent's plan is to make it easier for app developers to use services that network equipment can provide, such as authentication and security, to streamline the software-production process and, at the same time, improve the efficiency of network usage. For example, network-based data stores could stop applications from polling all the time by delivering data actively, although these push techniques are not always kind to the network if they're not well optimised.

An engineer from one equipment supplier pointed out that, by only delivering one email at a time, push email contributes to the signalling load rather than reducing it.

Microsoft embedded software architect Mike Hall says a lot comes down to the protocols that back-end services use - often optimised for local-area networks - as some protocols do not deal well with the high-latency environment of today's mobile networks.

Developers and operating-system providers could address the tendency for mobile apps to go back to the network every time they wake up.

Hall says: 'As a developer, you have to think about the connected and disconnected states. In many cases, with a smartphone, you may not be connected. At the moment I have data roaming switched off because it's too expensive where I am. But many apps assume a connection to get data. If they don't have a connection those apps are dead. They could cache content: the data may be stable but if I can pull in background data, that could help. However, with caching, you have to consider security and privacy.'

Hall concedes that, right now, data persistence is something for the developer to sort out on an operating system such as Windows Embedded 7. 'But it's certainly something we are looking at and thinking about.'

Spencer says standards will be vital for the new environment if it is to take off. 'It is a new challenge for our industry. The ways that standards bodies have worked in the past are now being stretched. One of the big problems is scale. Notionally, you have a global audience but there is no operator in the world that has a global user base. So you need scale across the networks.'

If operators balkanise access to their services, it will be too difficult for developers to write for them economically - and the operators will not reap the benefit of a more efficient network.

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