ICAO Lays Out Spectrum Priorities for Upcoming World Conference

The ICAO positions on WRC-12 agenda items were approved by its Council and sent to member countries and relevant international organizations, it said. The positions aim to protect aeronautical spectrum for radiocommunication and radionavigation systems required for existing and future safety-of-flight applications, it said. Safety considerations dictate that “exclusive frequency bands must be allocated to safety critical aeronautical systems and that adequate protection against harmful interference must be ensured,” it said. The report also includes proposals for new aeronautical allocations to new aeronautical applications. Support from administrations is the only way to ensure that the WRC-12 will reflect civil aviation’s spectrum needs, it said.

ICAO is expecting to develop prescriptive standards for unmanned aerial systems’ (UAS) communications systems, it said. Spectrum for UAS for safety and regularity of flight, especially in civil airspace, will need to be under an aeronautical mobile (route) service (AM(R)S), aeronautical mobile-satellite (route) service (AMS(R)S), or the aeronautical radionavigation service to have the necessary status and sufficient protection from harmful interference, it said. Using the mobile satellite service (MSS) to provide an AMS(R)S must clearly identify in the Radio Regulations the band being used to provide the aeronautical safety service as well as the appropriate level of priority and pre-emption, ICAO said. Other provisions may be needed, it said.

Difficult discussion in the WRC-12 preparatory process has focused on the possibility of using fixed satellite service (FSS), with additional conditions or restrictions, for applications to control certain aspects of UAS systems beyond line of sight. The European group has not yet submitted a position on the agenda item. The 5030-5091 MHz band is an appropriate band to satisfy the terrestrial line-of-sight, spectrum requirements for the command and control of UASs in non-segregated airspace, the U.S. position said. “Currently, there is minimum usage in this band worldwide,” it said. No new spectrum allocations should be made to meet payload requirements, ICAO said.

Another difficult agenda item deals with ensuring long-term spectrum availability and access to spectrum necessary to meet requirements for the AMS(R)S. Decker Anstrom, head of the U.S. delegation to WRC-12, in a July press briefing said the agenda item presents “an extremely complex set of issues.” The agenda item will be “the subject of a good deal more discussion between now and [the meeting in] Geneva,” Anstrom said. The four-week WRC will be in Geneva, starting in January. Aeronautical interests want more involvement in certain coordination aspects for its AMS(R)S spectrum requirements in the 1.5/1.6 GHz bands. ITU-R studies have examined use of the bands 1525-1559 MHz and 1626.5-1660.5 MHz by the MSS.

Regulatory measures are needed to “preclude the operation of software defined radios” in bands allocated to aeronautical services unless they're intended for and have been properly certified for use in an aeronautical application, ICAO said. The organization also wants to preclude operation of cognitive radio systems in bands allocated to aeronautical services. Cognitive systems rely on being able to detect all transmitters, ICAO said. Many aeronautical systems are based on a ground-based transmitter providing a service to airborne receivers, it said, thus it is very possible for a cognitive radio to be beyond the line-of-sight of the transmitter but still within line-of-sight of the airborne receiver. This can result in interference to that receiver, it said.

ICAO supports new regulatory measures to spur introduction of future AM(R)S systems in the bands 112-117.975 MHz, 960-1164 MHz, and 5000-5030 MHz if spectrum requirements for airport surface applications can’t be fully accommodated within 5091-5150 MHz. Compatibility studies would have to first be successfully completed, it said. Neither the AM(R)S operational environment, nor the radionavigation-satellite service (RNSS) signal characteristics are sufficiently defined to finalize ITU-R studies, so no allocation is proposed for the AM(R)S in the band 5010-5030 MHz.

ICAO supports possible measures to enhance the international regulatory framework as long as they don’t adversely impact aeronautical use and the protection of systems. ICAO opposes any allocation under the agenda item on harmonizing spectrum for electronic news gathering that would adversely affect aeronautical interests. The intergovernmental organization wants to make sure that introduction of any new modulation techniques or changes to frequencies or channeling arrangements for the maritime mobile service don’t adversely affect AM(R)S. Technical protection limits for fixed, mobile, space research (space-to-Earth) and the fixed-satellite (space-to-Earth) services with primary allocations in the band 37-38 MHz should be introduced so compatible aeronautical mobile services can be developed, ICAO said.

Any allocations to accommodate radars in the range 30-300 MHz displaced by the fixed and mobile services and also to meet emerging requirements for greater resolution and range for various space object detection applications should avoid the bands 74.8-75.2 MHz, and 108-137 MHz, ICAO said. Radiolocation service (RLS) in the VHF frequency range is coming under increased pressure from co-frequency fixed and mobile services, it said. The bands 112-117.975 and 117.975-137 MHz are also heavily used by aeronautical systems, it said. Any allocation should not adversely affect the operation of existing and planned aeronautical systems, it said. Compatibility studies should consider aeronautical bands adjacent to high powered transmitters in the RLS, it said.

Operation of short-range devices in any bands allocated to aeronautical services should be opposed, ICAO said. Provisions in the Radio Regulations need to ensure that short-range devices cannot cause harmful interference to aeronautical systems, ICAO said. Any allocation or possible allocations to RLS in the range 3-50 MHz should not cause interference with existing or planned aeronautical systems, it said. If a primary allocation to RLS is made in the band 15.4-15.7 GHz, it should not cause harmful interference to the aeronautical radionavigation service, ICAO said, nor should it require protection.

The organization also would oppose new MSS allocations that would adversely affect aviation interests. An ITU-R report indicates a shortfall of spectrum available for the satellite component of International Mobile Telecommunications (IMT), the international standard for advanced wireless communications, but studies need to be done to identify additional spectrum for MSS systems which are not part of the IMT satellite component, ICAO said.

Installed wireless avionics intra-communications (WAIC) may spur more cost-efficient and environmentally friendly air transportation while maintaining required levels of safety and reliability while providing environmental benefits such as reduction of aircraft carbon footprints and lower costs to manufacturers and operators, ICAO said. The organization supported a future WRC agenda item on the systems.

ICAO also wants some country footnotes to be removed from the Radio Regulations. Fixed service should be eliminated in the band 1559-1610 MHz, ICAO said. The band is allocated, on a worldwide, primary basis, to the aeronautical radionavigation service (ARNS) and to RNSS. Fixed use is scheduled to be terminated in 2015, but the date “constitutes a severe and unacceptable constraint on the safe and effective use of GNSS in some areas of the world,” ICAO said. The countries with the footnote are in Europe and Africa.

ICAO also referred to removing footnotes for the mobile service in the bands 74.8-75.2 MHz, 108-117.975 MHz, and 328.6-335.4 MHz. The footnotes “do not represent a realistic expectation” that mobile will be introduced in the bands. Egypt, Israel, Syria, and Pakistan have the allocations. Footnotes for fixed and mobile services in the band 1215-1300 MHz, mostly used by countries on the African continent and in the Asia-Pacific region, should also be removed, it said. Norway should also remove a footnote authorizing fixed stations north of 60° in 283.5-490 and 510-526.5 kHz.