Friday, March 10, 2006

Ridin' the WiMAX train

Today I took a ride on the Southern Trains London-Brighton service, in a train equipped with T-Mobile's on-train HotSpot - and I have to say I was very impressed. T-Mobile has spent the last several months fine-tuning the network, which currently consists of Redline directional antennas (operating at 5.4GHz) deployed by partner Nomad Digital in stations along the route, with 3G coverage filling in the gaps. The trains are fitted with discreet antennae on the carriage roofs, and the Nomad access points are entirely invisible to the passengers, concealed in cabinets at the end of the carriages.

As with my post the other day on Telabria, I find this interesting because it employs a technology which has so far failed to see significant consumer uptake (3G) as an enabler of a technology which has in fact been a tremendous success (WiFi), without requiring the user to buy a new device. This isn't what the carriers had in mind originally, but it is a way to get network utilization rates up, and for someone like DT, with feet planted in both 3G and WiFi camps, why not roll with it? Besides, as we know, most of the really interesting developments in telecom have been unanticipated.

It is my understanding that T-Mobile is currently increasing 3G coverage along the route, and doing some selective HSDPA upgrades as well, which makes sense to me - why not concentrate effort where there is some decent chance of people actually using the network, whether they know it or not? Though what the user sees is basically a mobile WiFi service, behind the scenes there are a lot of potential applications which benefit the train operator, relating to monitoring of various technical functions of the train (electrical network, temperature, the dreaded toilet failure) as well as passenger security. Some of these have been available previously via GSM but now can be richer and in real time. No doubt we will see extensions of these in future with the advent of RFID.

I shot a four minute video, but I am dissatisfied with it and will refrain from posting it. First, due to a re-jig of some of the rolling stock by the train operator, we were unable to make the entire journey to Brighton. Instead we had to go to East Croydon and then return to Victoria on an inbound WiFi train. Unfortunately this only gave me about 20 minutes on the move. Secondly, the video is pretty poor quality and fairly dull from a visual perspective. Again, the short trip duration and the very crowded conditions on the train didn't allow me to produce the Fellini-esque cinematographical effects I had hoped for.

My companion on the journey was measuring latency throughout and we could see that our connection was moving quite frequently from WiMAX to 3G, but from the end-user perspective there was no perceptible change - and definitely no interruption of the signal at any time. I understand that, depending on the backhaul available, T-Mobile is getting throughput of 1 - 2Mbps at times, though a 6Mbps upgrade is in the works. I was running Skype in the background as well as a BitTorrent client, but I only realized later that I was not pushing the network nearly hard enough. The top speed I observed was 400kbps, but I later realized that the Torrent file I was downloading only had one peer who was not particularly stable. I made a Skype video call after we pulled into the station (with BT still running in the background) - both audio and video quality were excellent. Next time I will endeavor to make the entire London-Brighton journey and really see what this network can do - and shoot a watchable piece of video to document it.

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