Wi-Fi – why not?

Some of the world’s leading high technology companies are grappling with the task of making Wi-Fi available in moving vehicles. Transport correspondent Max Glaskin asks whether it is worth the effort.

Wi-Fi has changed the communication habits of millions, allowing them to connect to the internet without being tied down by wires. They benefit from cheap data transfer, video and audio calls through VoIP and access to personally-relevant information.

Target range
It could do the same for people on the road, plus give them position- and journey-specific information if it wasn’t for one significant problem: Wi-Fi signals have a very limited range – 100 metres (300 feet) on a good day.

This doesn’t matter for homes, offices, hotels, airports and coffee shops. However, it is a massive barrier that, so far, is preventing the successful implementation of Wi-Fi as a communication medium for vehicles.

Granted, there are some exceptions. This week Chrysler’s 2009 US models have gone on sale, some with the option of Wi-Fi. Don’t be bamboozled – this system simply creates a Wi-Fi hotspot within the car to allow devices to connect wirelessly. The crucial link between the vehicle and the internet service provider is made by a good, old-fashioned cell phone chip. Compared to direct Wi-Fi, it is expensive to transfer data through a cell phone.

Elsewhere, some high speed trains in Europe promise the availability of Wi-Fi. These, though, have powerful, dedicated track-side base stations and on-board equipment to store a buffer of data so that the individual user doesn’t see the gaps when the train loses signal.

Now Microsoft and researchers from two US universities are keen to develop Wi-Fi for road vehicles (see: Microsoft test-drives Wi-Fi in vehicles).

They are addressing the fact that vehicles quickly pass through a Wi-Fi hotspot before having to establish a secure connection with the next one. While a simple Wi-Fi aerial does the job for a device at home, additional on-board technology is needed within a car, bus or truck.

Hotspot handovers

This is because the Wi-Fi protocol says a device can connect to only one base at a time. It effectively prevents a Wi-Fi vehicle from taking advantage of the fact that many hotspots overlap.

So special algorithms have been written enabling a device to monitor the signals from several neighbouring and overlapping hotspots and to calculate which provides the best chance of a smooth hand-over and a strong connection. This is smart thinking and has, apparently, been demonstrated successfully on Microsoft’s own campus.

While it is a very clever approach, it leaves a lot of questions unanswered. For a start, the gaps in Wi-Fi coverage are massive in even the densest developed countries. In some regions it is still not possible to get a mobile phone signal, let alone Wi-Fi.

A question of profit
And what can Wi-Fi deliver that cannot now be obtained through mobile phone, satellite radio, in-car entertainment systems, FM, AM, DAB and GPS signals? The key driver appears to be the promise of cheap data transfer, including voice calls, but the service will never begin until someone works out how to make a big profit from it.

Call me churlish, call me old-fashioned and call me naïve. But don’t expect to call me in my car on Wi-Fi any time soon.
 

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