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(ARCHIVED) Summary of submissions for 56 MHz channels in V, U, X and 38 GHz bands


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This is the summary of submissions and Radio Spectrum Management (RSM) responses published on the conclusion of the proposal for 56 MHz channels in V, U, X and 38 GHz bands.

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RSM response


Submitter: Chorus

Expresses strong support for allowing 56 MHz channels in the V, U, X and 38 GHz bands

 

Is keen to see prompt implementation of the proposed establishment of 56MHz channel spacing.

 

Submitter: Downer New Zealand

Does not support the proposal

 

Considers simply widening the channel occupancy from (say) 28MHz to 56MHz seems to be a retrograde step, when the Ministry is pushing for ever narrowing of channels to squeeze more services into the available spectrum.

RSM aims to achieve the most efficient use of spectrum possible.  In recent years demand has increased for higher capacity DMR delivering faster backhaul and data speeds.  Recently we have received requests for wider (56 MHz) channel spacing. Some of the equipment now available can deliver more than 500 Mbps in a 56 MHz channel. This type of equipment is very spectrally efficient at almost 9 bits per hertz per second. To deliver similar speeds in the current 28 MHz channel may requires two to three channels and much greater equipment costs.

 

Considers the wider bandwidth will exacerbate finding new allocations in already congested geographical areas.

Notes that the expanding use of "Last Mile" digital microwave radio (DMR) equipment for "Long Haul" routes. Modern equipment just doesn't appear to have adequate filtering to operate in multi-channel n+1 or parallel path multi-operator configuration.

Considers that using wider bandwidths caters for a lazy design evaluation and reservation of spectrum for future use. e.g. equipment operating at lower modulation schemes (say 34Mb at C-QPSK) on day one of a link provides much-more-than-adequate fade margin if the link is designed to cater for much higher future capacity (say 155Mb at 128QAM). This methodology doesn't meet the certifier’s obligation for the link to operate at just-adequate-for-the-service requirement of PIB38. Notes that the ever increasing demand to reduce establishment costs at the expense of spectrum efficiency. Higher spec equipment and antennas, use of non-frequency consuming diversity techniques etc all cost more to implement, but generally are more efficient on spectrum use.

To ensure that the new 56 MHz channels are used efficiently a minimum requirement of 4 bits per hertz per second has been added to PIB 38. 

Considers that the Ministry doesn't appear to have adequately tackled the issues of equipment & antenna performance in Defined Metropolitan Areas to improve spectrum re-use in the DMAs

Defined Metropolitan Area (DMAs) are a concept in the Radio Licencing Certification Rules (PIB 38) that give a simple description of New Zealand’s Metropolitan areas where the radio spectrum has greater usage. In the case of DMR a higher grade of antenna is required in some bands within DMAs. Reviewing the antenna and equipment requirements for DMAs is outside the scope of this proposal but more stringent requirements could be considered as part of the up-coming fixed service review.


Submitter: Hugh Railton

Supports 56 MHz channels in the 38 GHz band.

 

Notes that the directivity at these frequencies is very sharp and a large amount of frequency reuse is possible.  Provided the normal engineering is done there is unlikely to be any interference limitation. Notes that the the situation of the lower bands has not been considered.

 

Submitter: Jonathon Brewer

Does not immediately support 56 MHz channel spacing in the V,U,X, and 38GHz and considers other issues need to be resolved first.

 

Considers that this issue cannot however be viewed in isolation.  Notes many users seek V, U, and X because there is no available spectrum in lower bands. Notes that one user has hundreds of licenses in the R band which have not been used in five or more years. These licenses *must* be revoked so that other users can access spectrum before making changes to existing, relatively congested bands.

 

R band is outside the scope of this proposal. However, the upcoming fixed service review project may look at some of these issues.  


Submitter: Kordia

Expresses some support for some bands and makes recommendations on how 56 MHz channels should be implemented

 
 

Kordia describes two channel arrangements; edge aligned and carrier aligned (details are given in their submission. Kordia recommends that in the interest of spectrum efficiency, the ITU-R “edge aligned” method should be used.

 
 
V band

Notes that PIB 22 channel plans do conform with edge aligned plans

 

Notes that there is not much spectrum in V band and would only allow three pairs of 28 MHz channels and one pair of 56 MHz channels.

 
 

Considers that although 3 pairs of 28 MHz channels in the non-TVOB part of V-band could be useful for high capacity links, there is only enough spectrum for one pair of 56 MHz channels. One pair of 56 MHz channels would not be worthwhile.

Three pairs of 28 MHz and one 56 MHz channel pairs have been implemented and do not overlap the TVOB channels.

Notes that in the event that one pair of 56 MHz channels is implemented in two adjacent 28 MHz channels, Kordia recommends that an overlapping half-offset 56 MHz channel pair should not be created in channels V4 & V5.

U band

Notes that the 7 MHz channels in U band comply with ITU-R F.385-9 but the 28 MHz channels do not. Also notes that several assignments are not on the 28 MHz raster

We note that the 28MHz channel plan is from Annex 5 of ITU-R Recommendation F.385-9. We note that the 7MHz plan aligns with the main part of the recommendation.

Kordia suggest some approaches for dealing with non ITU-R F.385-9 28 MHz U band channels.
 
 

Propose a range of options for going forward in their submission but see the following as the most pragmatic solution:

 
  • Notes that new equipment is generally available for operation on ITU-R channels, but notes that initially it would be impractical to re-tune existing 28 MHz. recommends that new licences for 28 MHz and 56 MHz to be aligned with the main F.385-9 channels. Considers that the existing licences on the annex 5 channel plan be allowed to continue but be notified that retuning is required at a future date. Suggest that this date be set on the basis of the typical age of existing licences, to allow for realistic amortisation and the natural equipment replacement cycle.
 

A 56MHz channel plan and a new 28 MHz channel plan has been created that aligns with the main part of the ITU-R recommendation F.385-9. The existing 28 MHz (Annex 5) channel plan has been maintained and is available but it is noted in PIB 22 that it is not the preferred channel plan. Currently there is no plan for the cessation licences on the existing 28 MHz channel plan. The existing channel plan could be an item for discussion in the fixed service review. It is noted that Approved Persons will need to be conscious of the overlaps when conducting certification work.

X band

Kordia notes that X band channel plan in PIB 22 conforms with ITU-R Rec. F.497-7

The lowest 56 MHz X band channel (12779 MHz & 13045 MHz) has not been implemented due to the concerns expressed about interference to Ku band satellite receivers. Further studies may be required and we note that it as a possible item for the fixed service review.

 

Kordia has concern that because of the wider bandwidth of 56 MHz channels there will be more out of band emissions falling into the adjacent Ku band satellite

 

Kordia recommends that the 56MHz channels adjacent to Ku band satellite not be used until further studies have been conducted on the effect of OOB.

 
Recommends that 3 – 4 channel pairs are accommodated
38 GHz band

Considers the 38 GHz band is well suited to 56 MHz channels and can accommodate up to 20 56 MHz channels.

 

 

Last updated 9 December 2014