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WORKING PAPER
AERONAUTICAL COMMUNICATIONS PANEL (ACP)
30TH MEETING OF THE WORKING GROUP F (WG F)
Pattaya, Thailand 13 – 19 March 2014
Agenda Item 7: WRC Agenda Items
Proposed Reply LS to WP 1B on the Development of Dynamic Spectrum Access Devices
(Presented by Andrew Roy)
SUMMARY
IP01 is a LS statement form ITU-R WP 5B expressing its concerns on
the development of Whitespace (since renamed to Dynamic Spectrum
Access) devices. This WP is a proposed LS to ITU-R WP 1B on
ICAO’s concerns should the work go forward.
ACTION
The Working Group is invited to note the proposed text and approve the
attached LS to send back to WP 1B.
INTRODUCTION
WP 5B has copied a Liaison Statement to ICAO on WP 1B’s development of new PDNR
ITU-R SM.[DYNAMIC ACCESS] ‘Spectrum management principles and spectrum engineering
techniques for dynamic access to spectrum by radio systems employing cognitive capabilities’ 1.
This Working Paper proposes a LS to WP 1B expressing some initial views of ICAO on the concept
and current work.
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1 Originally developed as SM.[WHITE-SPACE] “Spectrum management principles and spectrum
engineering techniques for dynamic access to spectrum by radio systems employing cognitive
capabilities”.
DISCUSSION
The development of Dynamic Spectrum Access Devices (DSAD) is based on cognitive
radio systems accessing temporarily unused/unoccupied spectrum. This has expanded on the
original intent of the whitespace proposal, allowing applications to operate in any band without an
allocation. Such a possibility could have a detrimental impact without full compatibility testing and
coordination, especially with highly sensitive passive aeronautical navigational aids.
Liaison statements from 4A and 4C (Documents 1B/136 and 1B/140 respectively) have
already pointed out the regulatory implications of such a concept, claiming that WP 1B is
overstepping its remit in such a wide ranging capability. Given discussions in the ITU community,
it is expected that other working parties will also be providing similar comments on the regulatory
implications of such an approach.
Given previously liaison statements received from the responsible working parties, the draft
PDNR is already considering it unsuitable for certain radiocommunication services. However,
aviation bands are not explicitly mentioned. Therefore, the draft liaison statement at Annex A is
proposed to bring to the attention of WP 1B the technical and operational concerns of ICAO.
ACTIONS FOR THE MEETING
The meeting is invited to:
a. Note the content of this paper
b. Approve the draft LS attached at Annex A for sending to WP 1B.
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Annex A
International Civil Aviation Authority (ICAO)
LIAISON STATEMENT TO
WORKING PARTY 1B (COPIED TO WORKING PARTY 4A, 4C, 5B, IMO AND
WMO FOR INFORMATION)
WORKING DOCUMENT TOWARDS A PRELIMINARY DRAFT NEW
REPORT ITU-R SM.[DYNAMIC ACCESS]
Spectrum management principles and spectrum engineering techniques for
dynamic access to spectrum by radio systems employing cognitive capabilities
INTRODUCTION
ICAO has been informed of WP 1B’s work on the PDNR ITU-R SM.[DYNAMIC ACCESS]
‘Spectrum management principles and spectrum engineering techniques for dynamic access to
spectrum by radio systems employing cognitive capabilities’2, and has also taken into account
WP 5B’s views (Document 1B/106). Given the current development of Dynamic Spectrum Access
Devices (DSAD), ICAO has the following views:
SAFETY OF AERONAUTICAL SERVICES
The protection of aeronautical safety services is critical to the safe operation of aircraft. Even
minimal levels of interference can put at risk the safety of operational aircraft. Therefore, ICAO
has serious concerns about DSADs seeking to share with aeronautical safety services, and
recommends that these devices be excluded from operating in the same frequency bands.
COMPATIBILITY WITH AERONAUTICAL RADIONAVIGATION AND
RADIOCOMMUNICATION SYSTEMS
DSAD compatibility studies assume a transmitter and receiver are at the same location, ICAO notes
that this is not generally true for different aeronautical systems. For example several aeronautical
navigations aids only transmit information for reception by passive receivers, the majority of which
are based on aircraft and are therefore highly mobile at a range of altitudes and with very large radio
line of sight. Additionally, new bi-static radar technology is currently under development (see
Document 5B/475, Annex 12), that geographically separate the transmitter and receiver.
As another example, some aeronautical datalink communication systems used for the control of
aircraft operate on a Carrier Sense-Multiple Access (CSMA) mechanism. These systems detect
power in the received channel and will not transmit should it exceed a set level. Even a small level
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2 Originally developed as SM.[WHITE-SPACE] “Spectrum management principles and spectrum
engineering techniques for dynamic access to spectrum by radio systems employing cognitive
capabilities”.
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of intermittent interference will make the receiver believe the channel is occupied and dramatically
increase the system latency to pass messages to aircraft. This will reduce the system performance
beyond the required levels for the safe operation of air traffic control.
CONCLUSION
Given the views expressed above, ICAO is of the opinion that aeronautical safety services used for
communications and radionavigation are not compatible with the proposed DSAD concept. Such
devices have the potential to cause significant disruption the both radiocommunication and
radionavigation aeronautical systems, and this would be an unacceptable risk to aviation safety in
ICAO’s view.
ICAO notes that the current draft of PDNR ITU-R SM.[DYNAMIC ACCESS] recommends to
exclude frequency bands allocated to the radiodetermination service that are classed as safety of
life. Given the above information, ICAO would recommend that the PDNR specifically excludes
all terrestrial and satellite radiocommunication and radionavigation frequency bands used for
aeronautical safety services.
Status:
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Contact:
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