Summary

Over the last two decades there has been a marked increase in the demand for connection to high speed data networks and this has resulted in an unprecedented expansion of the use of optical fibre. However many localities requiring high speed access are still not connected and this has led to major development programmes being contemplated within industry and supported by government.

Whilst optical fibre is a good solution where economic, often radio linking is preferred as it does not require the laying of cables and can be carried out relatively quickly. At the same time demand for high capacity cost effective radio linking is increasing technological development has resulted in linking equipment operating in the millimeter bands (bands above 30 GHz) becoming available. In particular there are now a number of manufacturers providing high capacity point-to-point linking equipment in the 70-90 GHz band.

The purpose of this paper is to seek the views of those with an interest on options for future regulatory arrangements for high capacity short haul point to point linking in the 70-90 GHz band.

At millimeter wavelengths relatively small antennas (about 30 cm) can provide very high antenna gains. Such antennas have very narrow beam-widths (less than 1.2º), and there is an opportunity to re-use the frequency very often. Propagation at these frequencies is strictly line-of-sight. Careful antenna placement using local shielding can lead to even higher frequency re-use. It is expected that dozens of such point-to-point links could traverse most cities. Typical data sheets indicate that this technology can support applications requiring throughputs of up to 10 Gbps over path lengths of up to 8 km.

Because of the relatively high degree of frequency re-use, most spectrum management authorities overseas that have already provided access to this band have opted for very simple licensing arrangements that places the responsibility for path planning and any interference resolution onto the licensee. This is called ‘self co-ordination’ in Australia and the UK.

In the New Zealand context it is expected that access to this band would provide for a range of short-haul point-to-point links that would compliment development of the optical fibre network. For example, there are a number of buildings not yet connected by fibre and this technology could provide a cost-effective approach to bring connectivity to these buildings.

This paper examines the regulatory regimes in place in other nations and outlines three options for high-capacity short haul point to point links in New Zealand.