Addressing HF Interference for Aeronautical Bands at WRC-2003

1. CAR/SAM RPM/WRC-2003 WP/XXCARS/SAM Regional Preparatory Meeting for WRC-2003 AGENDA ITEM 2Measures to address unauthorised use of and Interference to the Aeronautical HF bands (WRC-2003 Agenda Item 1.14)Presented by: Jim WellerSpectrum ManagerAirservices AustraliaMEXICO CITY, 11 – 12 DECEMBER 2002

2. Introduction • What is the problem? • Is it still a problem? • Background • Progress • What can WE do about it NOW?

3. Sources of HF Interference Extract from WRC-2000 Paper Doc 136 (USA)

4. Sources of HF Interference Extract from WRC-2000 Paper Doc 136 (USA)

5. Is it still a problem? • As of 2001 …Australian Flight Information Service operators and pilots reported 3 major sources of Interference on the HF aeronautical mobile (R) service frequencies ·Authorised co-channel voice transmissions ·Unauthorised co-channel voice transmissions ·Data transmissions

6. Extract from Airservices’ Report on HF Aeronautical Mobile (R) Services Interference during the ITU Second Special Monitoring Programme, 25 June – 1 July 2001 (ITU Circular letter (CR/147))

7. Background • WRC-2003 Agenda item 1.14 • ITU Resolution 207

8. WRC-03 agenda item 1.14 “to consider measures to address harmful interference in the bands allocated to the maritime mobile and aeronautical mobile (R) services taking into account Resolutions 207 (Rev. WRC-2000) and 350 (WRC-2000), ….”

9. ITU Resolution 207 • Measures to address unauthorized use of and interference to frequencies inthe bands allocated to the maritime mobile service andto the aeronautical mobile (R) service • The World Radiocommunication Conference (Istanbul, 2000), • resolves to invite ITU-R and ITU-D, as appropriate • to study possible technical and regulatory solutions to assist in the mitigation ofinterference … • to increase regional awareness of appropriate practices in order to help mitigateinterference in the HF bands, especially on distress and safety channels; • 3 to report the results of the above studies to the next competent conference (ie WRC-2003),

10. Resolution 207 (cont’d) urges administrations 2 to make every effort to identify and locate the source of any unauthorized emissioncapable of endangering human life or property and the safe and regular conduct of aircraftoperations, and to communicate their findings to the Radiocommunication Bureau; 3 to participate in the monitoring programmes that the Radiocommunication Bureaumay organize pursuant to this Resolution; 4 to make every effort to prevent unauthorized transmissions in bands allocated to themaritime mobile service and the aeronautical mobile (R) service; 5 to request their competent authorities to take, within their respective jurisdiction,such legislative or regulatory measures which they consider necessary or appropriate in order toprevent stations from unauthorized use of distress and safety channels or from operating incontravention of No. S23.2;

11. Progress … • Special ITU-R Monitoring Programme - Administrations and Aviation Authorities participated in Monitoring of HF Aeronautical frequencies as per ITU CR/147 - 20-26 Nov 2000, 25 June – 1 July 2001, 14 –20 Jan 2002 - ITU Report expected by end of 2002 • Australian Aviation Study - Submitted as AMCP WGF7 WP/31 (Bangkok, Nov 01) - Further discussion through APT WP4 Bulletin Board (BB) and Correspondence Group (CG) • CPM Text - draft CPM text developed at AMCP WGF7 (Bangkok, Nov 01) - submitted at ITU-R WP8B (May 02) - adopted at CPM02-2 with input from SC02 and APT

12. Proposed Solution (CPM Text) • No suitable comprehensive technical solution has been found to eliminate interference. • Enforcement of existing regulatory provisions and cooperative actions by administrations, together with … • Recommended Measures and Techniques to reduce interference: ·Alternative modulation methods ·Passive and active/adaptive antenna systems ·Channel barring ·Regional Monitoring and DF ·Transmission of Warning Messages ·Education and Publicity

13. (1) Alternative modulation methods • Digital Modulation protocols (FSK, QPSK etc.) as a replacement for analogue SSB voice communications would reduce the effect of interference on communication. • ICAO has adopted HF datalink (HFDL) packet data communication as part of the aeronautical telecommunications network (ATN) – refer Annex 10, Vol. III, Part I, Ch 11. • Not a replacement but supplement for voice communications. • Disadv: The cost of implementing a replacement for voice communications system internationally in aircraft and at base stations. • Disadv: Does not remove interference from the channel.

14. (2) Passive & active/adaptive antenna systems • Antenna is the most influential element in determining the performance of the HF radio system. • Passive antenna: Directivity, Takeoff angle (modes), Polarisation. eg Near Vertical Incidence Skywave (NVIS), Multi-modes • Active antenna: Beam shaping. Eg Phased arrays • Antenna voting at antenna and/or location level. • Adv: Can be implemented country-by-country. • Disadv: Cost to implement may preclude uptake. • Disadv: Major benefit only to ground operator.

15. (3) Channel barring of TX equipment • Legislative action that requires HF radio equipment manufacturers to prevent users of their equipment from accessing aeronautical channels (through electronic barring) without proper authorisation. • More practical for new equipment, but maybe retrospective with financial incentive for returned equipment (as part of education/promotion programme). • New equipment have digital tuners so the modification required would be minimal. • Allows Regulators to be pro-active on this issue without the high ongoing costs of policing. • Benefits to both operators (pilots) and base stations (flight service) in the aeronautical and maritime services.

16. (4) Regional Monitoring and DF • Indirect mitigation technique • Ability to ascertain the location of unauthorised users would enable regional authorities to assess the severity of the problem and to police it. • Implementation of a comprehensive and effective HF Monitoring and Direction Finding Network would require cooperation and commitment from many Regional member states. • System accuracy proportional to the number and geographic spread of monitoring stations. • Airservices makes use of an Interference Report form (refer AMCP WGF/7 WP/31 attachment 3) to report harmful interference to the Regulator (ACA).

17. (5) Transmission of warning messages • Transmission of a warning message on the channel affected by persistent harmful interference. • Airservices’ Broadcast tapes are in five languages (Bahasa Indonesian, Korean, Taiwanese, Japanese and Chinese). • Australian Flight Information Service have a digital service integrated in consoles. • Australian Communications Authority Monitoring Station (Quoin Ridge, Tasmania) reports that these tapes are very successful to clear frequency in short term. • Long term effectiveness difficult to be assessed. • Potential for interference to authorised users.

18. (6) Education and Publicity • Encourage and assist in regional education and publicity of the proper use of aeronautical radiocommunications spectrum. • Encourage the establishment and support of closer international and regional liaison with national administrations (regulators) and aviation authorities.

19. What can WE do about it NOW? • Review ITU Report from Special Monitoring programme http://itu.int/brtpr/monitoring/index.html • Support the CPM text directly or via Regulators at WRC-2003 • Raise concern and encourage Regulators to enforce Radio Regulation. • Countries adopt appropriate mitigation measures and techniques in consultation with ICAO.

20. DISCUSSION AND FEEDBACK Questions?? Contact: jim.weller@airservices.gov.au