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Call quality in decline: is it the smartphone?

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Category: Femto cells



Studies suggest that as smart phones get smarter, voice quality seems worsen. Last year, a survey by JD Power among North American mobile users looked at wireless call quality based on seven problem areas that impact overall carrier performance: dropped calls; static/interference; failed call connection on the first try; voice distortion; echoes; no immediate voicemail notification; and no immediate text message notification.

Problems were measured per 100 calls (PP100). During 2010, call problems increased from 11 PP100 to 13 PP100, and increased again in the most recent study to 14 PP100.

Smartphone users seems to be getting the rawest deal, with customers experiencing problems at a rate that is 6 PP100 greater than problems experienced by traditional handset customers. In addition, smartphone customers are nearly three times more likely to experience dropped calls than are customers with “dumb” handsets.

So what is the cause? Are handset manufacturers skimping on quality components?

One argument is that with so much processing power and electronics condensed into a slim, light package, manufacturers just don’t have the space for improving the microphones and noise cancellation capabilities.

And yet reviews are not always dreadful. This review of the voice quality of iPhone 3GS, HTC Hero, HTC Touch 2 and Blackberry Curve concludes that smartphones’ performance is fair rather than poor.

So, if smartphone call quality is declining, but not necessarily caused by handset shortcomings, what is the cause? Could it be our changing usage patterns?

Could the increasing use of mobile applications – from texting, social media, online gaming or music streaming – be having a negative impact on the voice quality we experience? In all likelihood, this is probably the biggest factor: short-comings in the network.

As more people use more data, there is simply less bandwidth available for voice. Operators typically compress packetized voice, but if you compress too much, then quality inevitably suffers. The use of statistically multiplexing can impinge quality even further. (Admittedly, operators are now looking to hi-def voice compression to improve this.)

And the fact that calls – and data sessions – are most likely conducted indoors, does not help matters. The JD Power study found that 56% of calls are made in the home. Many more calls also indoors such as in offices or shops. And it’s indoors where mobile coverage is at its poorest.  The macro networks strain to reach through walls and windows to provide the mobile user with a call quality they expect from their long-neglected fixed line.  It is perhaps only the large buckets of inclusive minutes that encourage mobile subscribers to make calls, while at home, with their mobile first and the fixed line second, because it’s unlikely to be superior call quality.

Get a femtocell

I am lucky enough to have a nice office in central London, and a home office a few miles away – consequently my mobile phone is an indispensable business tool.  Yet despite living in an area where mobile network coverage has been pervasive for a decade and a half, the network performance I experience is very inconsistent, drifting between fast HSDPA and sluggish GPRS depending on where I am in my home office, implying that I am at the edge of a macro cell.

Will a femto cell dramatically improve my call quality and mobile data performance or is the iPhone just not that great for conducting two hour audio conferences with parties from all over the world?

The best way to find out whether it’s the handset or the network is to test out Vodafone’s second generation of Sure Signal, which is currently the only femtocell service available in the UK. I’ll be reporting on this imminently.

Stewart Baines is a writer with Futurity Media


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