FINAL REPORT - Stakeholders - Ofcom

might be effected through the implementation of completely new technologies (digital,
adaptive systems, see Section 6.7.6.
6.7.5 Possible New Technologies (in-band)
There is also the possibility to use many of the techniques addressed in section 6.5 within
the spectrum allocated to the maritime mobile and mobile services between 4 and 10
MHz. Firstly, NVIS propagation characteristics (see 6.5.3) might provide possibilities for
introducing more services in the range through sharing, however the main technology
challenges will be the development of antennas for mobile stations with a high launch
angle. Large vessels will of course be able to install the electrically low horizontal
antennas best suited for such propagation but this may not apply to land vehicles if
sharing was to be contemplated.
a) Digital technology
WRC-97 considered that it would be desirable to extend the use of digital technology to
the maritime HF A1A Morse telegraphy bands since these bands were significantly
underutilised and that the requirement for the use of new digital technologies in the
maritime mobile service was growing rapidly. Consequently, the WRC adopted
amendments to the Radio Regulations to provide for the use of digital telecommunication
technology in the maritime HF telephony and A1A Morse bands. It noted that the use of
the maritime HF A1A Morse radiotelegraphy bands was steadily diminishing with the
result that administrations were already beginning to use these bands for digital systems
on a non-interference basis. It is known that in some countries internet (email) services
are being implemented on these frequencies.
WRC-2003 reviewed, under its agenda item 1.14, the frequency and channel
arrangements in the maritime MF and HF bands concerning the use of digital technology,
also taking account of Resolution 347 (WRC-97, subsequently abrogated at WRC-2003)
of the Radio Regulations. Consequently, it revised Appendix 17 to the RR to allow for
initial testing and the possible future introduction within the maritime service of new digital
technologies (Appendix 17, Part A, note p to the table). In its Resolution COM4/2 it
considered that the need to use new digital technologies in the maritime mobile service is
growing rapidly and that the use of new digital technology on maritime HF and MF
frequencies will make it possible to respond better to the emerging demand for new
services. ITU-R is already conducting studies to improve the efficient use of these
maritime bands. These studies can benefit from different digital technologies developed
for other services. ITU-R has been requested by WRC-2003 to finalise these ongoing
studies urgently including proposing a timetable for the introduction of these new digital
technologies.
It is recommended that every effort is made to support these studies and refrain from
implementing national solutions that might not be compatible with future systems.
With regard to SSB telephony, it would seem premature to consider a change-over to
digital techniques. In the longer term a transition to digital techniques, perhaps similar to
that use for digital HF broadcasting, may be advocated.
b) Adaptive systems
Adaptive technology is addressed in detail in section 6.5.1. This is certainly another area
that might offer opportunities to the maritime HF community and at the same time make
much better use of the available frequency spectrum is adaptive systems. Adaptive
systems are systems which can automatically select the optimum channel from an
assigned group, which release the channel when no traffic is present, thus allowing
frequencies to be shared more effectively and efficiently, reducing interference between
users and providing the ability to increase traffic density. Adaptive systems make it
possible to achieve a higher quality of service by combining an ability to exploit modern
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