Future communications systems -Connexion



AERONAUTICAL COMMUNICATIONS PANEL (ACP)

Working Group C – 6th meeting

Toulouse, France

20-24 October 2003

Agenda item 6: Evaluation of potential technologies

Future Communications System

Presented by

Alvin H. Burgemeister

B-twelve Associates, Inc.

Connexion by BoeingSM

International Coordinating Council of Aerospace Industries Associations (ICCAIA)

SUMMARY

This paper gives details of the operational and architecture aspects of the new Aeronautical Mobile Satellite Service (AMSS) that was approved at the ITU World Radio-communication Conference (WRC-2003) to operate in the frequency band 14-14.5 GHz.

Introduction

Aircraft operators, and in particular the operations and maintenance divisions, today increasingly desire continuous connectivity with the aircraft and crew. No matter where they may be, in-flight, on the ground, the concept of continuous communication and monitoring of aircraft is a priority issue of airlines seeking to maximise efficiency and productivity from their most valuable assets.

Additionally, cccommercial airlines generate more than five billion passenger miles annually with more than 40 million business travellers worldwide. Seventy-five percent of business travellers bring along a laptop when they travel. As connectivity is increasingly associated with computer use, its availability promotes and stimulates use of computers. To meet the requirements of this emerging market, various entities have undertaken development of systems that will enable broadband access onboard aircraft.

Boeing has developed an Aeronautical Mobile Satellite Service (AMSS) that provides in-flight broadband connectivity to airplanes for the benefit of aircraft operators, crew and passengers. It offers air travellers broadband, satellite-based connectivity comparable to what they experience in a modern office environment. Other entities are also developing similar systems.

Boeing, thru its business unit Connexion by Boeing (CBB), will enter into commercial service on regularly scheduled commercial flights beginning in the first quarter of 2004. Connexion by Boeing offers a system that has been developed with the assistance of twenty of the world's leading airlines to ensure that it has the features, functionality and ease of use they require. Service will begin on some trans-oceanic and trans-continental flights offered by Lufthansa, Scandinavian Airline System (SAS), Japan Airlines (JAL), and All Nippon Airways (ANA). Coverage will soon expand to additional airlines and routes. Service to routes covering Mexico, the Caribbean, Central America and South America will begin in 2005, with full global coverage anticipated in 2006.

CBB is already available on a number of VIP executive and government aircraft – including those manufactured by Boeing and Airbus.

The Connexion by Boeing AMSS offers real-time access to the Internet, e-mail and information content, and enables VPN secure access to company intranet and e-mail accounts. Connexion by Boeing also offers airline operators the ability to improve operational efficiency and enhance security in addition to meeting the connectivity needs of travellers. The dynamic broadband capability of the Connexion by Boeing service makes it possible to monitor from the ground the performance of airplane systems, enabling timely maintenance and reducing delays. Future applications could include the ability to have ill passengers assessed remotely by qualified medical professionals on the ground and onboard security monitoring is also under development.

Connexion One is Boeing’s flying test bed for the Boeing AMSS system.

Services Overview

CBB offers its service on a contractual basis to commercial airlines, private aircraft owners, corporate business jets and government agencies, which will have flexibility in how they utilise the service. This is not dis-similar to current ACARS service providers other than the fact that the AMSS has a much greater data capability than these existing services. CBB will enable:

1. High-Speed Internet Access. Passengers will be able to access the World Wide Web, send and receive e-mail, follow business and financial news, get updates on sports and world events, book reservations at hotels and restaurants, check weather forecasts, and execute stock trades – all in real time at broadband speeds;

2. Corporate Intranet Access. Business travellers will have the potential to log on to their company’s intranet while in-flight, thus allowing travellers to stay in contact with colleagues and to access networked files;

3. Travel Information. Airlines will be able to expand their provision of information needed by passengers to make their travel more enjoyable and convenient, such as interactive airports maps, gate information, in-flight maps, and destination guides; and

4. Airline Information. Passengers will be able to interact with an airline carrier’s website to access travel planning, travel support, and frequent flyer information.

CBB, in its current form, also provides the potential to offer a wide-range of non-safety related operational services to aircraft operators and their crews. For example, the broadband capability of CBB makes possible access to flight scheduling information, weather updates, and other innovative in-flight applications such as the electronic flight bag and real time engine monitoring that can improve the efficiency and performance of aircraft operations and service.

Network Overview

The communication service to each aircraft in the system consists of two parts: one or more forward links and a return link. Each forward link carries data from the ground earth station, via satellite, to the airborne terminal at a nominal data rate of approximately 10 Mbps. Multiple airborne terminals share a forward link transponder signal, and each airborne terminal may receive signals from multiple forward links on the same satellite. The return link carries data from the airborne terminal to the ground earth station, via satellite, and may use transponders that are separate from the forward link. Each airborne terminal may transmit at a data rate between 16 kbps and 1.024 Mbps. Return link transponders will be shared by multiple airborne terminals.

Figure 1 depicts how the transmissions operate in conjunction with the aircraft, ground station, and FSS satellite. Note that this system utilizes leased capacity on-board operational FSS systems for AMSS service rather than using a dedicated AMSS space segment.

[pic]

Figure 1.

Transmissions within the AMSS System

As shown in Figure 2, the AMSS is divided into four segments:

1) an aircraft earth station consisting of a pair of phased array antennas or a mechanically steered reflector antenna and other on-board subsystems;

2) a space segment consisting of leased satellite transponders on existing in-orbit Geo-stationary satellites;

3) a land earth station segment consisting of one or more satellite land earth stations ("LESs") linked by leased capacity on terrestrial networks; and

4) a network operations centre ("NOC") segment.

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[pic]

Figure 2. Architecture

1 The Aircraft Earth Station Segment

The aircraft earth station ("AES") segment is composed of three subsystems: an Antenna Subsystem ("AS") which includes the airborne antennas and support electronics, a Receive and Transmit Subsystem ("RTS") which includes the modem and system controller, and an interface to the Cabin Distribution Subsystem ("CDS") that links the system to aircraft crew and passengers. The CDS itself will be specific to the airline and may be wired or wireless.

On-board users will be able to use a personal laptop computer or other device, such as a Personal Digital Assistant ("PDA"), to connect to the CDS.

Reception and transmission of the data by the AES is accomplished using either a pair of transmit and receive phased-array antennas or a mechanically steered reflector antenna, which are affixed to the fuselage of the aircraft. The radio link between the AES and the space segment is accomplished using spectrum in the 10.7 to 11.7 GHz band and the 12.2 to 12.75 GHz bands for reception (space-to-Earth) (limited to 11.7 to 12.2 GHz in Region 2) and 14 to 14.5 GHz frequency bands for transmission (Earth-to-space).

2 The Space Segment

The space segment will utilize previously coordinated transponders with existing landing rights. Forward link data will be up-linked from a land earth station ("LES") to the GSO satellite using the 14 GHz band and then down-linked from the satellite to the AES in the 10/11/12 GHz band. Similarly, return link data will be up-linked from the AES to the satellite using the 14 GHz band and then down-linked from the satellite back to the LES using the 10/11/12 GHz band. The forward and return links will use full transponders or fractional transponders depending on the demand in the region.

To provide coverage of international flight routes CBB will lease capacity on a number of satellites. Each satellite will provide coverage in one geographical region. Satellite coverage areas will be selected to provide a small amount of overlap at the region boundary so that the system coverage is contiguous.

Satellite transponders are being procured for CBB’s initial coverage area of air routes between portions of Asia and Europe and from Europe to North America.

3 The Land Earth Station Segment

The land earth station segment will utilize leased capacity on existing commercial earth stations in each region. The LESs provide the up and down links to the space segment and are connected to the NOC using leased capacity on private terrestrial networks. In some cases Internet traffic will be connected to the internet directly from the LES.

CBB has contracted for LES services in USA, Switzerland, Russia and Japan.

4 Network Operations Centre Segment

The NOC serves as the central monitoring and management facility for the CBB system. The NOC is connected to all of the LESs in the system using leased capacity on private terrestrial networks and serves all of the satellite coverage regions in the CBB system. The NOC also coordinates the handover of aircraft transitioning between two satellite coverage regions. In addition, the NOC is connected to the Internet and the various customer care and billing centres needed to support CBB using leased capacity on private terrestrial networks. The Links between the NOC and the other system components are shown in Figure 3.

[pic]

Figure 3. The Links Between the NOC and the Other System Components

CBB will retain control of operation, maintenance and use of the System – both at the point of transmission and the points of reception – on a contractual as well as operational basis. Thus, CBB will have the ability to shut down the network (or relevant parts of it) immediately if required.

Protection of Other Authorized Services

1 Fixed Satellite Service

AMSS systems protect GSO FSS satellite receivers in the 14 GHz band by controlling the aggregate EIRP spectral density in the direction of the GSO arc emitted by AES antennas to the level routinely required by VSAT operations. The maximum co-polarized component along the GSO arc of θ degrees from the antenna main beam will not exceed the following limits:

Angle off-axis Maximum EIRP in any 40 kHz band

2.5° ≤ θ ≤ 7.0° 33 - 25 log θ dBW

7.0° < θ ≤ 9.2° +12 dBW

9.2° < θ ≤ 48.0° 36 - 25 log θ dBW

θ > 48.0° -6 dBW

In addition the maximum EIRP of the cross-polarized component in any direction θ degrees from the antenna main beam axis will not exceed the following limits:

Angle off-axis Maximum EIRP in any 40 kHz band

2.5° ≤ θ ≤ 7.0° 23 - 25 log θ dBW

7.0° < θ ≤ 9.2° +2 dBW

The aggregate GSO arc EIRP spectral density given by this input power density and antenna gain pattern is also referred to as the EIRP spectral density envelope. These are equivalent to the levels in ITU-R Recommendation S.728-1.

2 Fixed Service

AMSS systems must comply with the power flux density (PFD) limits given in Recommendation ITU-R M.1643 for the protection of fixed service (“FS”) networks when in line-of-sight of co-frequency FS networks, i.e.:

(132 + 0.5 θ dB(W/m2) in 1 MHz for θ  ≤ 40°

(112 dB(W/m2) in 1 MHz for 40° < θ  ≤ 90°

where θ is the angle of arrival above the horizontal plane.

3 Radio Astronomy

The AMSS must also comply with the power flux density (PFD) limits given in Recommendation ITU-R M.1643 for the protection of radio astronomy sites operating in the 14.47-14.5 GHz band when in line-of-sight of such sites.

4 Space Research

AMSS systems will also comply with the provisions of Recommendation ITU-R M.1643 for the protection of space research sites operating in the 14-14.3 GHz band when in line-of-sight of such sites.

Use of CBB from the Passenger’s Perspective

To use the CBB system, the passenger will plug in a personal laptop computer or other device, such as a personal digital assistant (PDA) through a jack in the seat. This will connect the passenger through the aircraft’s cabin distribution subsystem to the aircraft’s in-flight entertainment system and to web and media servers located aboard the aircraft. After the connection is made, the passenger can choose from a menu of audio/video offerings, Internet and intranet access, airline information and in-flight shopping. Passengers will be able to pay for the Internet and intranet access through personal credit cards or through pre-established accounts. Certain services may be provided by the airline at no charge to the passenger.

To minimize the aircraft weight, the CBB system will also support operation of WLAN on board aircraft, in accordance with IEEE 802.11 a, b, and g. The operation of WLAN has been evaluated with regard to susceptibility of avionics and human health. Extensive tests were carried out Boeing 747-400 airframe and the results have shown there is no impact on the aircraft and passenger safety. Germany’s LBA and UK CAA certified CBB for in-flight wireless operation on 747- 400 aircraft. Further information is available at .

Regulatory Considerations

The 2003 World Radiocommunication Conference approved a secondary allocation to the Aeronautical Mobile-Satellite Service (Earth-to-space) in the 14-14.5 GHz band to make possible this provision of broadband to aircraft. This allocation, which expanded an existing Mobile-Satellite Service allocation, is provisionally effective from 5 July 2003. In addition, the 2003 Radiocommunication Assembly adopted Recommendation ITU-R M.1643 on the technical and operational requirements for aircraft earth stations communicating with Fixed-satellite service network transponders in the band 14-14.5 GHz (Earth-to-space). This Recommendation facilitates authorization of aircraft earth stations for worldwide AMSS networks.

A number of countries have already authorized CBB’s AMSS operations within their territories. As of this writing, these include the United States, Canada, several countries throughout Europe, and Sudan. In addition, the civil aviation authorities of the United States, Germany, and the United Kingdom have issued necessary authorizations for installation and operation of CBB systems including airworthiness certifications and aircraft radio station licenses for each aircraft equipped with CBB. Several countries have concluded that licensing of aircraft earth stations is not necessary providing they operate in accordance with relevant ITU-R Recommendations and the Chicago Convention. In many such cases, a simple authorization is granted by letter upon notification by the AMSS operator.

The Future

Broadband digital satellite communications is the future of aviation communications. Radio frequency spectrum allocated to aeronautical mobile satellite service is required to facilitate the near term implementation of broadband communications for aviation and efforts will be required in the future to maintain the spectrum allocation. This will require cooperation between ICAO and ITU-R. The benefits of broadband will enable the evolution of aviation communications and facilitate the aviation agenda for safety of flight, security of flight, efficiency of flight, sustainability of air carriers, and passenger satisfaction with flight.

Connexion by Boeing’s near-term focus is on meeting the needs of the aviation industry and its customers. The medium-term focus is on e-enabling airplanes using the wireless capability of the Connexion by Boeing system and its tremendous bandwidth to reduce weight, power requirements, and complexity on aircraft. Less weight and complexity bring natural operational benefits to airlines.

The demand on aeronautical spectrum, particularly in the VHF bands and satellite L-band, that support current aircraft data links, has reached saturation.

This fact was acknowledged at the ITU WRC-2003 and an agenda item for the next Conference was created – WRC 07 Agenda Item 1.6 – that seeks to find additional spectrum for use by aviation. The 11th Air Navigation Conference adopted a recommendation for ICAO to investigate new terrestrial and satellite based technologies for aeronautical communications. These studies were directed to include “ ….. solutions outside the VHF band and wide band communication systems based on evolving international telecommunications standards and satellite based systems.”

Therefore it is incumbent on the aeronautical community to continue with development of radio spectrum frequencies assigned for aviation use and maximise the potential usage, even in the case where spectrum is shared with other users.

7 Conclusion

The potential that exists in the Ku-band AMSS needs to be capitalised upon and, as such, WG C is asked to endorse this fact and commence a work program that will bring this service into the ICAO SARP’s.

In the longer term, applications that will support ATC services, on-board security and other innovative uses need to be developed to exploit the full use of this allocation.

Again, WG C is asked to look at the most appropriate applications for the Ku-band AMSS and develop proposals that will ensure the long-term availability and usage of this portion of radio spectrum for aeronautical use.

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