Can mobile telephone technology come out of the closet and be safe for in-flight use?
After years of speculation about the potential hazards of using mobile telephones on aircraft, a major industry team came to Farnborough to commit itself publicly to offering an in-flight cellular service from 2006.
Support for passenger cellphone use will be included in the portfolio of Inmarsat-connected communications services offered by a joint-venture company to be unveiled by Airbus, Sita and connectivity specialist Tenzing Communications at the World Airline Entertainment Association show in Seattle in September. Also on the menu will be internet and corporate network access, email, instant messaging, SMS and conventional in-seat telephony.
If the company can deliver on its promises, the result could be a revolution in passenger telephony, which has so far proved to be a commercial disappointment for airlines and service providers. Deterred by high prices, complex usage procedures and billing, and half-hearted promotion, passengers have decided that, when airborne at least, it is not good to talk. Taking down the barriers to cellphone use could change that.
Last month's announcement was the latest in a succession of moves that suggest inevitable progress towards something that has, until recently, been regarded with suspicion by airlines and regulators. By using Farnborough as its platform, the Sita-led group stole a publicity lead on rival Arinc, which revealed details of a similar scheme on the smaller stage of the Inmarsat Aeronautical conference in Montreal last month.
CDMAVs GSM
On the eve of Farnborough, US wireless technology provider Qualcomm said it had successfully demonstrated a system based on the CDMA cellular standard, which is more widely used in the USA than the European-originated GSM favoured by Arinc and Sita. Meanwhile, in Germany, the DLR aerospace research centre is poised to demonstrate, in flight on an Airbus A340, the onboard cellular technology that was first shown in public on the ground at ILA in Berlin earlier this year.
The success of the planned services will depend on the ability of their technical solutions to reassure regulators on two counts. The airworthiness authorities want to be certain that radiation from passengers' mobile telephones will not affect safety-critical aircraft systems; and the national telecoms authorities need evidence that transmissions from cellphones used at altitude will not "splash" over several ground base stations simultaneously and disrupt cellular networks.
The evidence so far is that the engineers believe they can meet those requirements with onboard systems that take control of the mobile telephone as soon as it is switched on, commanding it to operate at a much lower power level and to communicate only with the onboard "picocell" base station. Transmissions from the telephone are then passed via the picocell to the aircraft's standard satellite communications system for relay by satellite to ground fixed and mobile networks.
Developed as part of the European Commission-financed Wireless Cabin proof-of-concept programme, the system demonstrated at ILA in May showed the capabilities that can be expected from forthcoming operational installations.
"The demo combined GSM cellular and wireless LAN technologies," says DLR digital networks specialist Dr Axel Jahn. "Calls from visitors' own GSM telephones passed via our experimental onboard base station, the Inmarsat satellite system and a parallel simulated Ku-band link, and our ground station at Oberpfaffenhofen, before entering the ground fixed and mobile networks."
The asymmetric Ku-band link - 768kbit/s down, 144kbit/s up - was designed to show how the system could cope with the datastreams typical of new-generation cellular systems, which will be used increasingly to send short requests to websites and receive streams of rich media in return.
The DLR system showed its ability to control the power radiated by the cellphones and to compel them to use the base station, instead of registering with the terrestrial mobile networks. "Another interesting aspect of the demo was the inclusion of a working prototype flight-attendant panel," says Jahn. "It could be used to allow or block incoming and outgoing calls, and to assign priority for crew operational or emergency communications and telemedicine."
Next month's A340 flight demonstration will be based on a Siemens-developed GSM picocell. Other wireless technologies - Bluetooth and WiFi - will also be accommodated. The Wireless Cabin programme will be completed at year-end, and the results commercialised by a joint venture between Siemens and German communications technology company TriaGnoSys.
On the regulatory side, the aspiring service providers are encouraged by an apparent softening in the attitude to airborne use of personal electronic devices on the part of some airworthiness authorities, as evidenced by the recent certification of wireless LANs aboard aircraft operated by Lufthansa and Emirates. The work of RTCA special committee 202, set up last year at the request of the US Federal Aviation Administration to investigate onboard use of current-generation cellphones and laptops with Bluetooth and WiFi wireless capability, seems set to shed further objective light on an area where conjecture has so far dominated.
Convincing national telecoms authorities that their mobile networks will be unaffected could prove to be a bigger job, however. Arinc technical director John Little assured the Inmarsat conference that "issues associated with the use of GSM frequency spectrum are addressable". But he also described an onboard management system that, among other things, could shut off the cellular facility when the aircraft was passing through the airspace of any nation that barred in-flight mobile use.
The race between Arinc and Sita to be the first to introduce onboard cellular is now on. Sita will have the majority shareholding - around 60% - in the joint venture to be launched this September. The venture will absorb the existing business of Tenzing, the Sita in-flight passenger communications division, and Sita's relevant R&D activity. Sita and Tenzing are no newcomers to the passenger communications business, supplying a number of international carriers with satellite short messaging. Their most recent customer, Emirates, is also introducing wireless LAN access to the service.
The new venture's service is due to be certificated in the third quarter of next year and to be commercially available from mid-2006, when a European airline is likely to be the first to offer it.
Installation work
Airbus and Sita have been working on the required technology for around 18 months. According to Patrick Gavin, executive vice-president customer services at Airbus, the system is designed to work through the Inmarsat satcom already aboard most long-haul aircraft. The main installation work, to be performed over three nights when an aircraft is not in service, will involve the fitting of new avionics.
Passengers will be able to use their own portable devices with the service, and will be billed through their usual mobile telephone operators and internet service providers. Typical international roaming rates will apply to the cellphone service.
Arinc and partners Telenor Mobile and Telenor Satellite Services plan to launch their service in the next 12-18 months. They aim to enter into an agreement with an avionics supplier within the next month or two and to demonstrate their system in the first quarter of next year.
Acting as what they call an "aviation mobile operator", the partners plan to integrate their onboard technology - comprising a picocell and an off-the-shelf server - with satcom installations capable of working with the Inmarsat L-band and Arinc SkyLink Ku-band systems. On the ground, a new gateway unit will act as the interface between the satellite ground stations and national cellular networks.
An onboard management system modelled on an existing maritime unit will give cabin crew full control of the cabin cellular network. It will allow them to pre-empt the satcom system in the event of an aircraft operational emergency, shut down the cellular facility in off-limits airspace, and trigger cabin annunciators to inform passengers of network availability. Charges to passengers for using the system are expected to be based on current terrestrial GSM roaming charges.
US demonstration
The eve-of-show announcement by US digital wireless technology company Qualcomm and mobile satellite operator Globalstar is the newest development strand to emerge. They revealed just before the show that they had completed tests of CDMA-based in-flight telephones aboard an American Airlines aircraft.
The aircraft took off from Dallas/Fort Worth International Airport and circled at 25,000ft (7,600m) for the demonstration. Passengers were able to make and receive calls through an onboard CDMA picocell, which was connected to the global terrestrial phone network through the Globalstar low-Earth-orbit satellite system.
Users reported experiencing delays of about a second during calls, the lag being attributed to latency in the satellite connection. American Airlines says that the test revealed no interference with ground cellular networks. Scott Becker of Qualcomm says the system could be adapted to work with GSM and that the current capacity of 15 simultaneous calls could be increased by adding another picocell base station.
The data gathered will be used for continued research. American Airlines is also exploring the possibility of broadband wireless Internet access aboard its aircraft.
With the airline industry's two communications providers publicly committed to making onboard cellular technology work, and both the world's leading cellular standards accommodated, it can now be only a matter of time before the last obstacles to painless in-flight telephony are removed.
BRENDAN GALLAGHER
Source: Flight International
