There is growing international debate about the regulation of satellite spectrum, particularly in light of the increasing demand for mobile broadband services. The 3.6-4.2 GHz band of electromagnetic spectrum, known as the ‘C-band’, is central to the debate. It is currently used for satellite broadcasting communications, but mobile broadband operators are eager to use the band for their services.

Satellite service providers want the C-band maintained for their use and are reluctant to share the band. The issue will come to a head at the 2015 World Radiocommunications Conference (WRC).

Demand for spectrum

The WRC is considering allocating the C-band for increasingly in-demand mobile broadband operations. Consequently regulators all over the world are considering the reallocation. In Australia, the Australian Communications and Media Authority (ACMA) regulates satellite systems in accordance with regulations administered by the International Telecommunications Union (ITU). The ACMA is facing pressure to reallocate the C-band. The ACMA has estimated that in Australia an additional 150 MHz of spectrum allocated for mobile broadband will be required by 2020, taking into account the 800 MHz that has already been allocated for mobile broadband services.

The reallocation of the C-band would likely involve sharing the band between the two services, and imposing geographic separation between them – for example, so that satellite services could only be used in rural or remote areas and mobile services could only be used in metropolitan areas. This proposal could have a significant impact on satellite users of the C-band, principally satellite broadcasters.

The ACMA’s engagement on this issue to date has largely been a response to developments at the WRC. Australia is a relatively small country in terms of population and can therefore be described as a “technology taker” rather than a “technology maker”. In other words, if Australia made a decision to reallocate C-band to mobile broadband without other countries following suit, it is unlikely that equipment makers would make bespoke equipment (eg mobile phones) available to take advantage of this new allocation, purely to serve the small Australian market.

Essentially, this means that the ACMA is largely directed by international developments in making its spectrum allocation decisions. Nonetheless, even if the WRC decides against re-allocation or sharing of the C-band, ACMA may come under increasing pressure from operators of mobile broadband service providers to free up the band for their use.

The benefit of freeing up the C-band is obvious, as it will contribute to meeting the demand for mobile broadband. However, there are a number of key arguments against the move that are likely to be raised at WRC-15. Those arguments most relevant to the Australasian region are outlined below.

Risk to public interest services supplied over satellite

Satellite-based telecommunications services to remote areas, such as distance learning and television broadcasting could be put in danger. In addition, disaster recovery services that rely on satellites would be at risk if the band were reallocated.

Moreover, the C-band is almost totally immune to rain fade. For countries in Asia located in areas with high rain rates the C-band is often the only reliable means of communication. Thus, the C-band is important for Australia’s satellite network connecting diplomatic missions across the region. It is also important for many Pacific Island countries that rely on satellites for international connectivity.

Costs incurred in adapting to the change

There are also significant costs that could be incurred by industry if the change occurs. Satellites are very expensive and have lifecycles of 15-18 years. Any plans to clear the C-band will need a similar transition timeline.

Technical feasibility of satellite and mobile broadband services sharing C-band

According to the ACMA ‘Towards 2020 – Future spectrum requirements for mobile broadband’ paper, the satellite industry is looking to determine whether it is feasible to share the C-band so that satellite and terrestrial services (like mobile broadband) can co-exist. This would require a geographical separation between the two services.

Developing sharing arrangements may be difficult because satellite services are very sensitive to interference. Wireless mobile networks would need to operate far away from existing satellite earth stations to prevent interference.

WRC 2015

The Conference Preparatory Meeting which met after the WRC in 2012 decided to create a joint task group within the ITU radiocommunications sector for preparation on the WRC-15 agenda items on spectrum allocation. This task force, called ‘Joint Task Group 4-5-6-7’, will develop appropriate reports, studies and recommendations about the potential for the C-band to be reallocated to mobile broadband at WRC-15.

Accordingly, the outcome of that conference will assist the ACMA in deciding how to address the issue going forward. Satellite and mobile broadband operators alike will be waiting keenly to see how this issue progresses. In the meantime, the C-band remains allocated for satellite broadcasting.