FINAL REPORT - Stakeholders - Ofcom

• Optimisation of analogue voice services.
• Optimisation of current digital services.
• Wholescale movement of current analogue services to digital (both voice and
data, but primarily data) accompanied by an aggressive reduction in analogue
channels.
There is consensus within the aviation industry that the long term solution lies in the
movement to digital technologies. There is no shortage of possible candidates, although
the industry is slow to adopt any particular new solution primarily because:
• global consensus needs to be obtained in order not to burden operators with
multiple fit solutions;
• the cost of avionics is such as to preclude regular updating of technology.
This section assesses the possible evolution of communication services from the current
time to beyond 2015 taking account of a wide range of possible technologies:
• Current technologies which are already in operation:
• VHF Voice supported by 25 kHz and 8.33 kHz channel spacing
• HF voice
• ACARS supported by VHF, HFDL and AMSS
• Emerging technologies which have been subject to significant development work
by the aviation community and, in some cases, significant deployment decisions:
• VDL Mode 2
• VDL Mode 3;
• VDL Mode 4;
• Gatelink.
• Future technologies for which there are emerging development plans:
• Next Generation Satellite Service (NGSS);
• Satellite Data Link Service (SDLS);
• 3G/UMTS (CDMA Wideband);
• Boeing Connexion (Boeing CS).
Note that there is some overlap between technologies providing communication services
and those which could also support future surveillance services (this is discussed in
section 3.3.8).
5.2 Frequency Allocations (International & National)
5.2.1 HF Communications (R) and (OR)
For HF voice and data services, discrete frequency bands are allocated between 2880 -
22000 kHz (AM(R)S). There are 9 sub-bands, with the aeronautical allocation taking 1331
kHz in total.
5.2.2 VHF Communications(R) and (OR)
The VHF band for aeronautical communications stretches from 117.975 – 137.000 MHz
(AM(R)S) globally (all 3 ICAO regions).
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