High speeds at high speed

E&T looks at the many ways in which the telecoms and transport industries are converging.

Until a few years ago, most of the convergence between the world's transport and telecoms systems involved the use of a single communications technology per application: a radio link between aircraft and control tower; a broadcasting link between radio station and radio car; a global satellite navigation signal tracking the location of a ship; or an electric railway signal alerting train drivers about the status of the line ahead.

A more recent trend has seen the design of transport applications that rely on a variety of communications techniques. The phenomenon is the result of the inevitable replication in the transport sector of the convergence that has occurred within the telecoms sector.

Convergence in communications is happening on two fronts: at the network and the device levels. Those operators that used to provide phone services to residential and business customers now provide anything from Internet to fixed or mobile voice, mobile data, leased line, IT, network security, multichannel television or home networking services.

And mobile phones that used one radio frequency to communicate with cellular base stations are now sophisticated handheld computers featuring several radios for multi-band cellular service, Wi-Fi connectivity, Bluetooth access and GPS tracking, as well as USB connectors for the wired transfer of content.

How is this two-pronged telecoms convergence phenomenon being replicated in the transport sector? Let's take a look at a few examples.

Hotspots on rails

The reason why Wi-Fi wireless local area networks (WLANs) became so popular so quickly is simple. Here was a technology that was promising to do for the fixed Internet what the mobile phone had done for its fixed predecessor.

So it was only natural that what started as a few access points in an office here and a house there, to free the PC from the confines of a single room, would grow to encompass airport, hotel, café and citywide hotspot coverage.

The next logical step in making the Internet truly mobile was to make it accessible to those users who were genuinely on the move. Trains, ships, commercial airliners, business/government planes and even coaches and buses are being fitted with Wi-Fi access, which is then offered to passengers either as a complimentary or paid-for service, and to crew members as another way of communicating with a control centre.

All of these systems need a minimum of two different comms techniques in order to work: one to establish the wireless link with the passengers' Wi-Fi-enabled laptops or handheld devices; the other to route this data to and from the Internet backbone.

The former is relatively easy to set up as it doesn't differ much from other regular Wi-Fi hotspots, such as those commonly found in airport lounges or restaurants. A wired Ethernet network is used to interconnect the WLAN access points, the total number of which will depend on the size of the vehicle. In a small bus, a single access point mounted on the ceiling might be enough, whereas in a large train or cruise ship a couple of dozen or more will be needed.

Things get a bit more complicated when it comes to the backhaul portion of these moving networks. Here, the link with the Internet backbone will require the deployment of a second, and sometimes third, communications channel.

The first technical hurdle to overcome is how to establish and maintain a reliable bi-directional wireless broadband connection with a ship that will be navigating several nautical miles away from the nearest terrestrial infrastructure, a train that will constantly be passing through long tunnels or an aircraft that will be flying at over 10km and several hundred kilometres per hour.

Three main technologies are usually chosen to meet this challenge: satellite, cellular and WiMax. Train operators will normally go for a combination of these, sometimes using satellite for the downlink channel and cellular (GPRS or 3G, including HSPA) or WiMax for the uplink channel (and also the downlink for uninterrupted, in-tunnel coverage).

Newcastle-based Nomad Digital, which has helped equip Southern Railway's trains and the Heathrow Express with onboard Wi-Fi systems in the UK, is currently building what
it claims will be the world's longest wireless broadband corridor. This will run for the 600km of the Virgin Trains-operated line that links London and Glasgow.

In another project completed last year by Nomad in the US, the company managed to integrate even a fourth type of communications technology (fibre optics) in the backhaul portion of a Wi-Fi network built for the Utah Transit Authority. A trackside fibre cable running alongside the short, 64km route between Ogden and Salt Lake City is hooked directly to the Internet backbone on one end. At the other, it feeds a series of Redline WiMax base-stations located at intervals of between 800m and 4,000m along the tracks, which communicate with the on-board units fitted to the 12 double-decker trains.

This powerful configuration makes it the global railway industry's fastest Wi-Fi network so far.

Airline online

In the aviation sector, the collapse in 2006 of Connexion by Boeing, a company that the American aircraft manufacturer had created to market an in-flight online Internet service powered by two-way satellite connectivity, seemed to suggest that there simply wasn't a cost-effective way of 'feeding' these high-altitude, high-speed moving WLANs.

Apparently, though, there is. Or so the success that Aircell, a Denver, Colorado-based company, has recently had in selling its novel approach to domestic carriers such as American Airlines, Delta Airlines, Virgin America and United Airlines seems to suggest.

In 2006, Aircell won a Federal Communications Commission auction for an exclusive 3MHz chunk of air-to-ground spectrum. Then the company built a network of 92 cellular towers evenly distributed across the continental US. Each base-station operates like any other regular cellular mast, but with its antennas pointing up to the sky.

Passing planes fitted with a small transceiver on their bellies link the onboard Wi-Fi traffic with the Internet using the CDMA EVDO Rev. A cellular standard. As the planes advance, they automatically switch towers to maintain signal strength. Speeds of up to 3.1Mbit/s to the plane and 1.8Mbit/s to the ground are possible.

Marketed as Gogo, the technology doesn't work on flights over water, as the Boeing service did. But apart from the advantage that it's much cheaper to operate than the failed satellite-based system, the required onboard equipment weighs just 57kg and can be installed in an aircraft in a single day.

Floating car data

The process of collecting, analysing and reporting road traffic data is becoming increasingly sophisticated due to the emergence of techniques such as wireless signal extraction (or WiSE). An American firm called AirSage coined this term to describe the real-time traffic information service it provides to government transport agencies, navigation companies, TV/radio stations and fleet operators.

To detect the flow of passing vehicles, traditional systems rely on the deployment and maintenance of sensor-based networks, an approach that is time-consuming, disruptive and expensive.

Because of this, they additionally tend to offer limited coverage, both in terms of the size of the area they monitor and the granularity of the data within that area.

AirSage devised a traffic reporting system that does away with all these problems by determining the location, direction and speed of the ubiquitous mobile phones that drivers and passengers carry with them in their vehicles.

Courtesy of a deal struck with cellular operator Sprint Nextel, which conveniently has a nationwide network of base stations constantly tracking 50 million handsets, AirSage is able to extract anonymous data from Sprint's network. It then applies its patented algorithms to the data before presenting the results to customers in a user-friendly graphic interface.

Satellite navigation companies can then transmit this real-time data directly to GPS devices to inform drivers about surrounding traffic conditions and so help ease their journeys.

Container status monitoring

Another communications technology that has been gaining traction in the transport sector is RFID, or radio frequency identification.

This short-range wireless technology can be particularly useful when combined with satellite, cellular and Web-based interfaces to, for example, not only remotely track the location of a container aboard a cargo ship, but also identify individual items within the container, as well as monitor the temperature, vibrations and other parameters relevant to the transported goods.

OxLoc, an Oxford University spin-out recently acquired by Cybit, a UK telematics service provider, has been working on the development of battery-powered radio modules for the tracking and monitoring of remote assets. Its Container Alert units - which integrate sensors with RFID, GPS and GPRS connectivity and are mounted on individual shipping containers - enable the owner of the transported goods to keep a close eye on them throughout the logistics chain.

Should a refrigerated container halfway around the world suddenly lose power, an automatic report detailing the problem can be sent to the customer.

Such instantaneousness can mean precious dollars saved on insurance claims. And - presumably - avoid a couple of hundred cases of food poisoning.

Recent articles

Info Message

Our sites use cookies to support some functionality, and to collect anonymous user data.

Learn more about IET cookies and how to control them