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On-train Internet: should operators go with satellite? or trackside WiFi?

Expect a "lively debate" about whether two-way satellite, or trackside WiFi, is the best way to deliver the Internet to train passengers at next week's "Train Communications Systems" conference in London, as Nomad and 21 Net cross swords in public.

In the UK, the hype for train-internet systems has been exposed in the last year, with several technologies proving to be inadequate for the job.

Delegates to the conference should pick up broad hints, however, about some big European contracts due to be awarded for high speed broadband to passengers. These will, almost certainly, involve two-way satellite, say insiders.

Leading proponent of bi-directional satellites is Henry Hyde-Thomson, Chairman of 21Net  - a company which has done a pilot test of its technology in Spain, and in 2005 also in a Thalys trial between Brussels and Paris. Thalys is a joint venture 70% owned by SNCF in France, and 30% by Belgium operator SNCB.

Hyde-Thomson is known to regard current technology as "not quite up to the job" and when interviewed by NewsWireless recently, revealed that the key problem facing users of many satellite-based systems was simply that "the dishes are too big."

The 21Net solution will be unveiled in a year or less, when it produces a system based on a Phasor antenna array. That will eliminate the need to have a reflective dish, Hyde-Thomson believes.

In the meantime, however, the 21Net approach is not likely to dissuade the directors of Nomad from persisting with the approach of using track-side WiFi and their own backbone products, as the way of providing back-haul to the Internet.

As Hyde-Thomson put it: "It's probably horses for courses. In a big country like France and Spain, you can get nation wide cover immediately with satellite with low capex; but if you have short lines with high density of people, you can make a case for trackside as Nomad has done for the London Brighton and London Birmingham services."

There are, he feels, rather too many complex issues about access rights and planning permissions and spectrum allocation for this to work over long rail links through sparsely populated areas.

However, he believes that satellite comms has possibly failed to impress some operators in the past because of failures in antenna technology. "They have not been high gain enough," he believes. And in order to build a big enough dish, you need more space than UK trains have between train and tunnel roof.

But he refused to be drawn on which specific antenna systems were likely to fall short, or which services used them.

Phasor Solutions believes that a fully steerable antenna array solves this problem. Phased Array Antennas are arrays of small antennas. "By adjusting the relative phase of the signal received by (or transmitted from) each antenna element it is possible to electronically steer the beam to point precisely in a given direction and to dynamically adjust the beam direction to compensate for movements of the antenna or satellite," says the Phasor marketing blurb.

"That will be big, high gain, and won't require a rotating turntable to hold the dish," Hyde-Thomson says. "It will add only three millimetres to the height of the coach."

Hyde-Thomson said he was "currently unable to discuss" any contracts which would use the 21Net solution using current antenna technology, but insisted that "you won't have to wait for the Phasor antenna before you see a genuine, high-speed, multi-megabit, two-way service to a passenger train operation in Europe."

Sources close to Nokia Siemens hinted at an announcement "this month" but refused to give details.