3.2.2 Fixed links, including studio-to-transmitter links

Two types of fixed link services use the 806-960 MHz band, both of which are licensed under the administrative radio licensing regime.

A 6-MHz pair, at 806-812 MHz and 851-857 MHz (the “KK band”), is allocated for bidirectional low capacity data links. This allocation is principally used by utility companies to monitor and control their networks using highly spectrally efficient digital equipment. The allocation appears to be well subscribed and in some areas it is congested. An increase in demand for licences has been observed as a result of new equipment becoming available in New Zealand for this band. Nationally, however, there does not currently appear to be a shortage of spectrum for licences in the KK band, nor any underused portions which could be reallocated to other applications.

Other jurisdictions use these bands for the same purpose (Australia), or land mobile radio (the US) and broadcasting (Europe). As land mobile radio and broadcasting requirements are addressed by allocations elsewhere, there would not seem to be any driver for considering allocation of the KK band for a different purpose.

Secondly, a total of 14 MHz of unpaired spectrum is allocated for unidirectional links, generally studio-to-transmitter links (STLs), used for the transportation of programme material from the studio to the transmitter site, in three sub-bands:

• 849-851 MHz

• 915-921 MHz

• 929-935 MHz

These allocations have become congested, particularly in the high-use areas of Auckland, Wellington and Christchurch, as a result of the increased number of FM broadcast services. In addition, the spectrum at 915-921 MHz is facing increasing risk of interference from the growing availability of short-range devices from the US and Australia which are designed to operate in that frequency range.

A consultation process over the period late 2004 to mid 2007 identified means of more efficiently utilising spectrum for STLs while also considering competing demands for the same spectrum. This work concluded that STLs should be moved from the 915-921 MHz band under a phased transition to enable the spectrum to be reallocated to short-range devices. The Ministry undertook to identify new spectrum to make available for STLs in the 806-960 MHz band once the cellular rights renewal process was completed. In addition, there was agreement that narrow-band mono STLs in the 900 MHz band should migrate to the 400 MHz band to help relieve congestion in the 900 MHz band.

Alternative technologies are available for transporting programmes to the transmitter site, including leased lines, infra-red links, microwave radio and satellite linking, but fixed links are commonly used, principally for cost reasons, as well as quality assurance.⁹

Various technical modifications to improve technical efficiency have been implemented over recent years, including optimising the channel assignments at major transmitter sites, reducing the maximum radiated power on short paths and implementing alternative antenna types. Other engineering refinements, which have been identified but not yet implemented, would also assist in improving the technical efficiency of band use, including removing the minimum path length in favour of common receive signal level for all new or modified links, and establishing engineering methods for determining the receive signal level.

Efficiency would also be improved by the introduction of digital equipment for STLs, which are almost exclusively engineered using analogue equipment at present. In most instances, digital equipment would provide greater spectrum efficiency and better tolerance to interference than analogue equipment, which requires a higher protection ratio.

In some cases, digital radio technologies can require different planning margins to avoid causing interference into analogue links on the same or adjacent channels. Previous consultations with industry found that it was desirable to segment the allocations to enable use of both analogue and digital technologies, but some digital licences are currently interleaved with analogue licences.

The Ministry considers that the licensee has the best information in order to manage the choice of technology to meet their requirements, and therefore it does not mandate the use of specific technologies in order to ease spectrum congestion in high-use areas. However, if demand for spectrum in a particular frequency range exceeds that which is available, then the radio licensing regime is not an efficient allocation mechanism, as it is a first-come, first-served system. While it enables the regulator to control licensing and to make efficient decisions regarding spectrum use based on technical parameters, it has no means of determining which of two or more competing requirements to use the spectrum has the highest economic value.

International harmonisation is not a dominant feature within this market sector, and hence there is little benefit to be gained from harmonising New Zealand’s fixed link allocations with those of trading partners.

Question 2

If your organisation uses the KK band (806-812 MHz and 851-857 MHz), do you consider that the Ministry’s assessment of utilisation of the band is accurate? If not, please explain.

Question 3

If your organisation has STL licences, do you consider that the Ministry’s assessment of the utilisation of the sub-bands (849-851 MHz, 915-921 MHz and 929-935 MHz) is accurate? If not, please explain.

Footnote

⁹ Industry feedback during the consultation process indicated concerns with alternative technologies, in particular capacity, quality, latency and redundancy limitations of wireline or satellite network infrastructure (Spectrum Allocations for Studio-to-Transmitter Links, Stage 2 Consultation: Summary of Submissions and Conclusions, September 2007, pp 24-25).