By Chris Green on Wednesday, 05 September 2007
 With more than 10,000 public Wi-Fi hotspots located around the UK, the chances are you will always be reasonably close to a location offering cheap high-speed internet access. Hotspots are already commonplace in most major coffee shop chains, many pubs, airport lounges and departure waiting areas, train stations, shopping centres, libraries, restaurants, cinemas and gyms. Now hotspot providers are tacking one of the most complex untapped markets for Wi-Fi users -- moving trains.
It's simple enough to provide wireless networking services in a static location. In its most straightforward form, providing Wi-Fi in a location is as simple as attaching a wireless access point or router to a wired broadband connection. In a fixed location such as a coffee shop, it is both easy and cheap to bring a broadband connection into the premises, then attach a Wi-Fi access point to it. This is then usually bolted to a wall in the customer area or close-by to keep it out of sight. In a moving environment such as a train, however, there is obviously no readily available wired broadband network to tap into. Wireless data services from satellites could be used, but would be very expensive and would immediately fail the moment a train entered a tunnel, or even a steep cutting.
Fortunately, there is a solution. By combining trackside communication networks for carrying the actual traffic and WiMAX wireless networking (in place of a wired broadband service) to feed a Wi-Fi access point, it's possible to deliver reliable high-speed internet access to a high-speed train both on the surface and underground.
 Wi-Fi services on trains are already operational on train services between London and Brighton, as well as being trailed on services to the North of England and the East coast. The latest train service to receive a Wi-Fi hotspot is the Heathrow Express high-speed train link between London's Paddington Station and the terminals at Heathrow airport. Around 15,000 passengers use the non-stop Heathrow Express service daily, a mixture of mostly business travellers and consumer passengers.
Joining forces
 The Heathrow Express Wi-Fi project is collaboration between the train operator, mobile phone and hotspot operator T-Mobile and Nomad Digital, a company specialising in building wireless networks in mobile environments such as trains.
The service operates both on the surface and in deep tunnels, making wireless signal delivery difficult. The Wi-Fi hotspot service provides passengers with a connection speed of up 2Mbit/s throughout the journey, including the main 6km tunnel section that runs in and out of the airport site. The original plan was offer transfer rates as high as 8Mbit/s, but this was scaled back to ensure reliability of the connection.
Bringing internet access to the train has been achieved by placing WiMAX transmitters along the track and in the tunnels. These communicate with access points on the train and relay the wireless signal, via WiMax, to the internet. This is in contrast to the London to Brighton service, which is also a T-Mobile hotspot. When in a tunnel, the service relies on a much lower bandwidth GPRS resulting in slow and occasionally dropped connections.
Less is more
The WiMAX network offers much longer range than conventional Wi-Fi, which means fewer transmitters are needed along the track. This also minimises the number of times the connection has to be relayed from one WiMAX transmitter to the next - a process that can result in a dropped connection, particularly when the rain is travelling at high speed.
The Heathrow Express service does raise one important question - just how useful is a Wi-Fi service on-board a train journey that only takes 15 minutes from start to finish? And remember, that's 15 minutes I which you have to settle into your seat, unpack your laptop, start Windows and establish an internet connection. The management of the Heathrow Express argue that given the abnormally high number of business travellers on the line, demand is there, even for such a short period of time.
"They are people who value their time, and now they can be in contact doing business in a reliable and fast way," said Brian Raven, managing director of Heathrow Express. He argues that even though the Heathrow Express service is a short journey, the large number of passengers along with users of Wi-Fi-enabled data devices such as smartphones and PDAs, as well as laptops, means there is demand for data connectivity in the same way there is for mobile phone services along the whole route. "For the business customers who frequent the train every second counts".
Using the Heathrow Express Hotspot
Using a Wi-FI hotspot on a moving train is no different to using one in a coffee shop from the same provider -- the pricing is the same, as are the log-in and airtime purchase pages.
nce on-board and your device is up and running, the T-Mobile hotspot is quickly found and offered for connection. All traffic is passed through a proxy, so when you first open the web browser and attempt to open a page, you're redirected to the T-Mobile Hotspot home page. In this case, one that's co-branded homepage with Heathrow Express.
There are several payment options. Existing T-Mobile mobile phone customers can send an SMS to receive a username and password that allows them to be billed via their mobile phone bill at 75p per each 10 minutes spent online. You can also buy ad-hoc access on-board with a credit card. Once you've signed into the service, you're online. A web-based counter shows you how long you've been connected and you need to keep this window open for when the times come to logoff.
The speed test tool at www.thinkbroadband.com gave results of 0.5Mbit/s for downloads and 1.1Mbit/s for uploads - well short of the services quoted 2Mbit/s, but still perfectly usable (and this was in a tunnel, too). More impressive was the fact that the connection was constant on both legs of the journey - it didn't drop once.
After switching on and launching a browser, all traffic is directed to a T-Mobile splash page, promoting you to log-in. |
