The idea of installing Wi-Fi on passenger trains has been around as long as the idea of installing wireless broadband on airplanes. But despite a number of trials and a handful of service launches - most of them in the UK and Europe - Wi-Fi on trains has been slow to catch on, especially in Asia.
There have already been trials in India, Australia, Japan and China, the latter of which showcased Wi-Fi connectivity on its high-speed train during the 2008 Beijing Olympics. But so far, only NTT Communications in Japan has announced any concrete plans. It will extend its HotSpot Wi-Fi service to N700 bullet trains in March this year - a full year behind schedule.
High-speed VSAT
To find a fully commercial Wi-Fi service onboard a moving train anywhere near Asia, you'll need to go to Kazakhstan.
Kazakhstan Temir Zholy, the country's national railway company, last August introduced Wi-Fi on the Tulpar train serving the 1,300-km route between Almaty and Astana. The VSAT-based system - the first in the region - was put together by government-owned incumbent telco Transtelecom, service provider Astel and satellite equipment and services vendor Gilat Network Systems (the turnkey supplier for the project).
The network consists of a Wi-Fi mesh network in the train cars (which allows cars to be coupled and decoupled without having to worry about reconnecting physical network cables) linked to a single auto-pointing VSAT on the roof that tracks the satellite's location while the train is in motion to provide a backhaul connection of 2 Mbps downlink and 256 kbps upstream.
The use of satellite as the backhaul for a train may sound like an obvious solution, but few train operators have actually used it to enable Wi-Fi. NTT Com, for example, is relying on a "leaky coax" solution - a cable running along the train route providing a wireless 2-Mbps connection.
Most players in the UK and Europe, however, are using either dedicated Wimax networks or 3G connectivity. But such solutions have their own challenges, from supporting high-speed handoffs to the familiar issue of providing consistent coverage in the rural zones where cross-country trains typically run - and where cellular coverage is typically weak or even non-existent.
"This is especially an issue in countries like Kazakhstan, where there is no cellular coverage at all outside the cities," says Gilat marketing VP Doron Elinav.
That said, VSAT-based IP backhaul for trains has its own challenges, from VSAT form factors and physical clearance to line-of-sight problems (i.e. tunnels) and the actual cost of the bandwidth link.
One thing that's not an issue, says Elinav, is the latency typically associated with running IP links via geostationary satellites, thanks to optimization software integrated in the VSAT that, among other things, prioritizes VoIP traffic.
Elinav said Gilat plans to add a GSM pico cell to the mix to support cellular voice.
One other issue is, of course, the business model - should passengers pay to surf, or should it be complementary?
The Kazakhstan service is opting for the latter, says Elinav. "It's more about getting more people onto trains who might otherwise fly. If you can convince more businessmen to take the train, there's more value in that to them than charging an extra $10 or $20 for internet."