FINAL REPORT - Stakeholders - Ofcom

However, in recent years, the rapid and fast-changing uptake of radio spectrum by new
services (using broadband, hiperLAN, AMSS technologies etc) has caused a shift in
thinking. The ITU no longer accepts the long-term ‘hoarding’ of frequencies; with WRCs
scheduled every four years and a continual cycle of preparation in regional organisations,
the ITU is able to consider new requirements and make the necessary changes to the
Radio Regulations. An example of this is the MLS frequency allocation (5000-5250MHz),
where only the bottom half of the band is actually used by ARNS; pressure is growing for
the unused portion to be reallocated on a primary basis.
Balanced against this is the current tendency to allocate bands to services, without
adequately judging the viability of sharing the allocation. The prime example is UWB,
which impacts several RNSS/ARNS bands with low power interference; the cumulative
effect of this interference may degrade RNSS signals as UWB proliferates.
The scenario involving decommissioning of VORs and NDBs would face resistance from
regulatory authorities – ICAO wish to maintain the allocations roughly 10 years past the
expected operational need. Any decisions taken should take this factor into account.
Public Perception: The short-term commercial considerations, so important in other
areas of frequency management (such as fixed services), do not apply to ARNS.
Although airlines (the eventual customers) operate reasonably short-term individual
policies, when they are considered as a body the requirements on air traffic services
change fairly slowly, particularly when discussing the removal of certain services.
From the public point of view, the availability and reliability of safety-of-life services in
aviation is taken for granted. Any reduction in the functioning of these services would not
be tolerated. As an example of this, the new GNSS solution (Galileo) has been developed
partly to allay fears that European users were relying on a US Military system with signals
that could be degraded if needed by the US Military (e.g. in wartime). Therefore, a
European civil system was designed to give unhindered access and performance.
When looking at decommissioning VORs and NDBs, an interesting point is raised
regarding the redundancy of RNAV – with no point-to-point navigation aids available, the
flight crew would have no back-up ‘first principles’ method if RNAV was incapacitated.
Safety studies are currently on-going to examine this point. If issues are found, it may
mean a reprieve for VORs.
The application of pricing
Ofcom, following a recent review of spectrum management, has been tasked with
encouraging greater spectrum efficiency through the use of administrative incentive
pricing (AIP) – prices set by the regulator that should reflect the opportunity cost of
spectrum use (thereby providing effective incentives for efficient use). AIP can influence
both the allocation of spectrum, and the assignment of spectrum rights; however, as
ARNS and RNSS allocation is generally governed by international agreements, it is in the
assigning of rights that AIP has the most leverage.
Balanced against this purely economic viewpoint is the cost of the social use of spectrum
– in short, the ‘opportunity cost’ of having a safety-of-life service of adequate performance
versus losing this safety-of-life service due to poor performance. In airborne navigation,
this ‘opportunity cost’ in most cases outweighs any considerations of pure pricing. Indeed,
in the recent Ofcom study on spectrum pricing it was suggested that any services
internationally allocated on an exclusive basis which do not experience in-band
congestion should be exempt from AIP. According to Cave, the effective opportunity cost
to individual users of ARNS is usually zero, due to mandated standards for safety-of-life
services – most often corresponding to a particular equipage on-board the aircraft (with
the notable example of 8.33 kHz vs. 25 kHz channel spacing in the VHF band, discussed
in aeronautical comms below). This applies to VORs, ILS and DME.
Page 120