FINAL REPORT - Stakeholders - Ofcom

5.3.5 UHF Communications > 862 MHz – Public Correspondence
Terrestrial public correspondence systems are in decline, the service provided did not
meet market expectations. The optimal solution would be to extend the ‘virtual home
environment’ to the air. In other works provide technical solutions which allow an aircraft
to become a visited public mobile telecommunications network and permit roaming of
terminals onto the internal network, GSM or IMT-2000.
Satellite 1.5/1.6 GHz Inmarsat systems also provide an opportunity to provide public
correspondence for passengers.
The average power of a UHF transceiver is between 20 and 30W.
5.4 Operational requirements
5.4.1 Overview of operational requirements
Communication is an essential part of air traffic service (ATS) provision and, for tactical
control of aircraft, provides a safety critical link between pilot and controller. Other ATS
requirements include delivery of air traffic information services (ATIS).
Aeronautical communications also includes non-ATS communication such as:
• AOC – Airline Operational Communications;
• AAC – Airline Administrative Communications;
• APC/IFE – Airline Passenger Correspondence/In Flight Entertainment.
AOC supports the regularity of flight and is considered as safety related. AOC is
traditionally supported by the same media as ATC.
Support for AOC applications is important to all airlines as it is seen as a key enabler of
operational efficiency benefits.
AAC and APC/IFE are non-safety related. AAC relates to typically narrow band
applications that support the airline operation but are not concerned with the safety and
regularity of flight, for example baggage handling. APC/IFE however has significantly
different characteristics to ATS communications and typically requires a broadband
solution.
There is increasing demand for all of these services as well as a new and increasing
demand for security related services such as video links from the cockpit.
5.4.2 Role of HF and HFDL in supporting the operational requirements
HF and HFDL are the only terrestrially-based means of communicating from remote or
oceanic areas – VHF and other ground-based frequencies propagate by line-of-sight.
ATC, weather and airline operations communications are passed via HF/HFDL.
As such, HF is necessary for the foreseeable future to provide redundancy for satellite
communications. Indeed, due to the cost of satellite communications, many users prefer
HF/HFDL in spite of the limitations. Also, satellite communications have a limited
coverage at the poles.
EUROCONTROL’s view is that there is a need to extend the allocation by at least 30 kHz,
due to increases of HF traffic of 9% per year in an already congested band. ICAO is
investigating the possibility of moving into the 5MHz band currently occupied by AMS
(OR). The introduction of HF datalink has increased the use of the band, and it is still
being implemented world-wide.
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