No hiding place in the skies

As many airlines start the roll out of wireless technologies onto their fleet, the day when passengers can stream their own selection of films onto their mobile devices on route to some far-off destination has just moved a little closer. Dr Dave Sloggett investigates

No hiding place in the skies

Time was when a journey by aircraft was a time to catch up on reading or watching a recently released movie that otherwise you might not have had time to go and see. When the flight attendants told you to switch off the mobile it was something you did almost with a sigh of relief. 

Sanctuary, for a brief moment in our increasingly busy lives - you were out of touch, beyond the blizzard of emails, texts and other social media interruptions that infect our everyday lives. That was until someone thought it would be a good idea to install Wi-Fi on aeroplanes.

First steps

The first tentative steps along this route were taken in the United States. The service provider GoGo built a network across America of 3G ground stations with their antennas pointing upwards into the sky. Much like when talking on the phone in a car, the planes pass from tower to tower as they fly overhead. The initial simplicity of the system, however, limited the total available bandwidth for each aircraft to just over 3Mbps. 

This was hardly the kind of level of network connectivity that people are used to on the ground. But it was a first step. The second generation of this system is now being rolled out and it will be based upon the ATG-4 technology. This is based on dual modems and steerable arrays, which will help boost the available bandwidth to 9.8Mbps when flying over the continental United States.

However, the relatively poor connection speeds have not seen an explosion in usage. Despite achieving an 81% market share, GoGo has yet to record a profit. If connection speeds cannot be increased to a level that will be attractive to users, the potential for accessing the internet in-flight may well go unrealised. For users, GoGo offers a range of alternative ways to pay for the service. 

Frequent fliers can pay $49.95 (£33) a month. A day pass for 24 hour access is $14 (£9), which is comparable to some hotel providers. These are based on buying the access before flying. With finite limits to what people will be prepared to pay, the current business model may not be viable. Existing bandwidth restrictions also mean that VoIP calls on services such as Skype are not supported. What is urgently needed is more bandwidth. 

Ocean coverage

One other issue also needs to be addressed. How to maintain services when the aircraft heads out across the oceanic routes? Once an aircraft leaves the coverage of the ground network a different solution has to be found. This involves beaming the signal to a series of satellites in low earth orbit. These relay the signal to a ground station for onward connection to the internet.  

Whilst airlines in America took the lead some of their European counterparts have been catching up quickly. Lufthansa’s service is called Flynet and offers download speeds of up to 50Mbps to the aircraft in the middle of the ocean. 

That has to be shared amongst all the potential users on the aircraft. Their service is also based on Ku-band. For the moment this is the frequency carrier of choice. The next generation of services, however, will migrate to the Ka-band (26.5-40GHz) which offers up to 100 times the bandwidth available in Ku-band. 

This offers the prospect of 12Mbps per passenger throughout the flight and may provide the breakthrough required for commercial viability. Perhaps understandably GoGo will be offering access to Ka-band services in 2014, although some technical challenges still need to be faced, such as latency. 

UK consultation

In the United Kingdom, Ofcom released a consultation paper on earth stations on mobile platforms (ESOMPS) located on aircraft, ships and trains in August 2013. The draft proposals envisage using the 27.5-27.8185 GHz, 28.4545-28.8265 GHz and 29.4625-30 GHz part of the radio spectrum to provide the service. 

These are areas of the spectrum not used in the United Kingdom by terrestrial radio services. They are already allocated for other types of satellite earth stations, including permanent earth stations and high density fixed satellite services (HDFSS). 

For aircraft based systems operating in these areas, Ofcom proposes that licensing arrangements to cover their operation will be established through issuing a variation of the current Aircraft Radio Licence issued by the Civil Aviation Authority (CAA). Ofcom also proposes that no additional fee will be charged for this process. It is a simple approach that is to be welcomed. 

Power constraints for the operation of the service to minimise the risk from interference are also proposed to be set in accordance with guidelines established by the European Union. This places the upper limit on the transmitter power at ≤ 55 dBW and that the elevation of the antenna shall be above 3° to avoid interference with ground systems. 

Latest US moves

In the United States in May, the FCC proposed releasing up to 500MHz of the radio spectrum with the explicit intention of increasing the bandwidth available to users in the air. The area of the radio spectrum that the FCC offered was between 14.0 to 14.5GHz in the Ku-band. This, however, is an area already used by commercial satellite operators. 

Seeing the proposal as a threat to the $1bn revenue stream currently enjoyed by the industry, the Satellite Industry Association was less than enthusiastic about the FCC’s proposals. Concerns over interference are central to the objections. 

The FCC countered this objection, making it clear that the proposal only involves using unused parts of the spectrum and stating its belief that the proposal will lead to greater competition and improved performance of air-to-ground internet services (AGIS). 

However, offering seamless access to online video streaming services so that customers can download their own choice of films is still some way in the future. But given the move towards the Ka-band, this proposal from the FCC may quickly become redundant. 

Whilst the regulatory authorities consult and discuss the best way forward from a technical viewpoint, some airlines are already pushing on with introducing new services. 

Pioneer airlines

The major US carrier United Airlines already boasts that of its fleet of A319 aircraft 55% are equipped with AGIS. Ten of its 747-400 aircraft are operational alongside 21 of the A320 fleet. In total in August, United Airlines had 61 aircraft equipped with AGIS. 

Assistance with using the AGIS is also helped with a comprehensive on-line information help service that answers a wide range of questions. Other airlines that offer GoGo broadband services include all of the fleet of Virgin America and Airtran. Air Canada, Alaska, American, Delta and US Airways are progressively introducing the services into their fleets. 

Aircell, the owners of GoGo, estimates that currently just over 1,000 aircraft in total have been equipped to operate AGIS. This is less than 10% of the total of 15,000 commercial airliners that are currently in service. Industry forecasts are predicting a near doubling of the number of passenger jets to a fleet of 31,500 by 2030. 

Installation costs to use the GoGo service are reported to be around $100,000 per aircraft. Airlines recoup this expense by sharing revenue with Aircell. Installation of the equipment takes around eight hours. This includes housing an antenna externally on the airframe.

BA and Virgin cautious

British Airways and Virgin Atlantic are taking a slightly more cautious approach to the introduction of AGIS. Virgin Atlantic is currently conducting flight trials on a limited number of aircraft. When complete a decision will be made on what to do next vis-à-vis the entire fleet. 

British Airways has focused on its business-class customers on the services to New York. Options to roll this out across the fleet are being investigated. The manufacturers of business-class jets have also been quick to install the technologies. 

Taking this to the next level and allowing customers to make phone calls whilst in the air is something that perhaps understandably has yet to win universal support. If the annoying person conversing on the train on the way home from the office invades your personal space for the time it takes to commute, imagine what it would be like if you were cooped up with them for 14 hours on a long-haul flight. That would be a serious case of there being no place to hide.

Written by Wireless magazine
Wireless magazine

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