FINAL REPORT - Stakeholders - Ofcom

4.3.3.8 Possible Overall Spectrum Efficiency Improvements
As with many of the ship-borne devices employed to assist visibility of objects, it is
changes in the specification of the interrogating radar that would bring about the greatest
potential efficiency gains, and not the transponders such as RTEs.
4.4 Conclusions and Recommendations
Though opportunities improving the spectral efficiency of the radar and associated
technologies used for maritime radiodetermination are limited, there are potential
modifications to spectrum use which could make overall more efficient use of spectrum.
Recommendation 4.1: The 5 GHz band is little used by (commercial) maritime radar in
and around the UK. It is already shared with PMSE and HiperLAN. Further sharing of this
spectrum with other, suitably compatible services should be investigated.
The fact that the existing 5 GHz maritime radar band is already successfully shared with
other compatible services implies that further sharing opportunities may exist.
Socio-Economic Issues
It is our understanding that few, if any, UK vessels are fitted with 5 GHz radar equipment.
Thus, the impact to the UK shipping community of the removal of (all or part of) this band
or increased sharing would be minimal both in terms of cost to the industry and in terms
of operational impact. However, there may still be occasions when non-UK registered
vessels which do use 5 GHz radars enter UK waters. This would have 2 potentially large
impacts:
UK services using the 5 GHz band may be impacted by the transmissions from the
radars. This is most likely to occur in coastal areas and the impact would depend, to a
large extent, on the technology chosen to operate in the band. For example, the existing
HiperLAN specifications take specific account of the presence of radars. Similar sharing
criteria 18 may need to be considered if the band is to be used for permanent (e.g.
operating 24 hours x 7 days) services.
The radars on the affected vessels will suffer interference. Unless the vessels are fitted
with ONLY a 5 GHz radar, which is unlikely if they are covered by GMDSS rules, as at
least one on-board radar must be in the 9 GHz band, and then interference to the radar
would not cause an operational problem. The situation is further improved by the fact that
the interference would occur when the radar was sweeping across the UK landmass, and
not whilst out to sea. Of course, this would hamper detection of other vessels between the
vessel and the coast but as the 9 GHz radars would continue to function, the overall loss
of visibility would be minimal.
Regulatory Impact
Increased sharing of the 5 GHz band with other services would not require a change to
any standard or specification relating to maritime radar equipment, as no change to the
radars themselves would be required.
The next step would be for Ofcom to determine appropriate sharing criteria for the band.
Such a determination will involve consideration of the role of the other services already
sharing the band and may show that further sharing is not practical. If such an
investigation did, however, prove the possibility of additional sharing, Ofcom may also
wish to consider giving notice that it intends to open the band for further sharing in order
18 Such as the use of Reed-Solomon or BCH codes
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