London still wi-fi king of the world

London has shored up its status as wi-fi capital of the world with usage soaring 156 per cent and the average session time lasting 72 minutes.

But the world is in the grip of wi-fi fever, according to the latest data from iPass' 'Wi-Fi Hotspot Index' for the second half of 2007. Business use of wireless hotspots almost doubled last year but the increasing popularity of 3G as a mobile broadband technology is also fuelling the connectivity storm.

Singapore and Tokyo were the second and third wi-fi cities respectively, with Tokyo racking up an impressive 118 per cent growth - taking it to within a hair's breadth of its Asian neighbour.

iPass, which gives mobile workers access to multiple networks through a single subscription, has now renamed its twice yearly survey the 'Mobile Broadband Index' to reflect rising usage of cellular technologies for getting online.

According to the index, wi-fi hotspot usage by business users increased 89 per cent over the same period the year before, with growth in Europe outstripping that in the US. Usage of wi-fi in Europe grew 142 per cent on the same period last year, compared to US growth of 61 per cent.

Overall, the US remains the most popular region in the world for wi-fi usage, followed by Europe and Asia Pacific.

Wi-fi growth in Latin America was "exceptional", said iPass, with usage soaring 133 per cent in the region.

The top 10 countries for wi-fi usage, in order, are: the US, the UK, Germany, Switzerland, the Netherlands, France, Japan, Australia, Belgium and Brazil - which makes its debut in the top 10 after tripling wi-fi usage.

Wi-fi at the airport

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The locations where mobile workers choose to log on to wireless networks continue to be dominated by traditional business travel venues. Airports are the hotspots of choice, accounting for almost half (45 per cent) of wi-fi sessions overall. And Heathrow was the fourth most popular airport in the world for wi-fi usage.

Hotels are also popular - accounting for almost one-third of global usage - and are becoming increasingly so, with 146 per cent growth on the same period last year. (Back in 2007, silicon.com ran a 'Fair Wi-fi' campaign calling for hotels to eschew overpriced fees for wireless internet access.)

Railway stations and ferries also contributed to worldwide wi-fi growth, according to the index, with usage at the former rocketing 238 per cent. iPass said new wi-fi deployments on trains are likely to continue to fuel this growth.

And if more rail operators follow the example of National Express, which offers free wi-fi on the UK's East Coast Main Line, this will surely be the case. The rail operator recently reported it has seen wi-fi usage triple on the line after making it free to log on.

The index also shows up a trend for increasing use of wi-fi in restaurants - which conjures up images of lonely business travellers at tables for one.

iPass found restaurant wi-fi usage was up 217 per cent year-over-year. By contrast, growth in cafés and book shops was much less impressive (35 per cent and 26 per cent respectively). Nonetheless cafés remain the most popular retail locations for wi-fi.

When it comes to alternatives to wi-fi, iPass found 3G is the dominant cellular tech - accounting for 70 per cent of all connections.

Monthly usage of 3G mobile broadband increased steadily through 2007, growing from an average of 152MB per user in Q1 to 190MB in Q4. The index also found the most established users tend to eat the most megabytes - suggesting usage rises with experience.

A surprising finding is that some users had to fall back on slower 2.5G technology, perhaps owing to 3G coverage issues: 62 per cent of users required 2.5G at some point each month.

A spokesman for iPass said enterprise mobile connectivity is likely to remain a tale of more than one technology.

He said in a statement: "The results of our Mobile Broadband Index suggest that no single technology can meet all the needs of an enterprise workforce. While 3G provides broadband download speeds in domestic metropolitan areas, users need wi-fi hotspots for fast bi-directional access everywhere else as well as to avoid high international 3G roaming charges. We expect both wi-fi hotspots and 3G to continue to grow as enterprises roll out a complete toolkit to their mobile workers."