What is mobile broadband?

Taking a laptop out to lunch isn’t always the most convenient option when you need internet access away from home though, which is why mobile broadband is now so popular.

Mobile broadband makes use of the 3G mobile phone network for internet access and the ‘broadband’ bit suggests that download speeds are on a par with home broadband connections. In theory, this isn’t too wide of the mark but, in practice, things aren’t quite so simple, as we will explain shortly.

‘3G’ is short for ‘third-generation’ and it’s the loose name for both a mobile phone network infrastructure (the phone masts and other bits of hardware) and the type of mobile phone hardware needed to make use of it.

As you can probably guess, 3G superseded the ‘2G’ mobile phone network, but don’t worry if that term doesn’t ring a bell. ‘Second-generation’ wasn’t ever used at the time to describe the GSM mobile phone network used throughout the 1990s and 2000s, nor was the analogue mobile network of the 1980s ever known as ‘1G’ – both names have only been applied to these two older mobile phone technologies in retrospect.

3G sets you free
Just like accessing a broadband internet connection at home requires a broadband modem, accessing the internet over a 3G network requires a 3G modem.

For a laptop, this usually comes in the form of a 3G ‘dongle’ (a small adapter that plugs into a USB port) or Mifi adapter (essentially a battery-powered dongle that connects to a laptop via Wifi).

Most modern 3G mobile phones can also work as a 3G modem, and just need to be ‘tethered’ to a computer, either with a suitable cable (available from the handset manufacturer), or using their built-in Wifi or Bluetooth connection.

‘3G’ may be short for ‘third-generation’, but the technology is more properly known as UMTS, or Universal Mobile Telecommunications System.

Modems and phones that support UMTS – which all do, if they’re sold as ‘3G’ – can download data at up to 2Mbits/sec when stationary, but this drops to 384Kbits/sec when the device in on the move, such as on a train.

However, UK 3G service providers (the five mobile phone networks, in other words) have long since upgraded their 3G networks to make them even faster, using a newer technology called HSDPA – High-Speed Downlink Packet Access.

This requires corresponding support in a 3G dongle or smartphone (which again, is something most modern devices have) and offers download speeds of up to 7.2Mbits/sec – with the potential to go much higher as the technology improves.

Whether it’s UMTS or HSDPA though, these quoted download speeds are all theoretical maximums that can only be attained under perfect conditions. As with home broadband, mobile broadband download speeds are always slower in practice, but not always by much.

A survey by broadband-comparison site Top10.com in January this year, for example, put O2 at the top of the pile with a download speed of 2.9Mbits/sec, which isn’t far off its marketing figure of “up to 3.6Mbits/sec”.

Speed ills
That Top10.com survey used average speeds, however, and how fast a mobile broadband connection is in any particular place depends on a number of factors.

Most important among these is 3G signal strength, which in turn depends on how far away the nearest 3G phone mast is. Sit on a park bench in a town where there’s a strong 3G signal, for example, and web pages will load like lightning; move indoors and the signal will degrade as it encounters absorbent walls and surfaces.

Head into the countryside, however, and you might struggle to get a 3G connection at all. Mobile broadband service providers tend to concentrate on towns and cities for their phone mast network, since serving such populated areas means they can quote figures such as “94 per cent population coverage” in their marketing. In more rural areas, however, phone masts are more widely distributed and may not offer 3G at all.

This is why it’s important to check a service provider’s 3G coverage for where you live (or where you want mobile internet access) before signing up. O2, Orange, Three, T-Mobile and Vodafone all have tools on their sites for checking street-level 3G coverage and, in 2009, Ofcom published maps for the UK that give a good (if slightly out of date) overview of 3G coverage.