Joint response from Inmarsat and Stratos
to the
ACMA consultation document “Earth station siting”, August 2011
21 Oct 2011
Introduction
This response has been prepared jointly by Inmarsat and Stratos. Inmarsat and Stratos welcome the opportunity to respond to the ACMA consultation on Earth Station Siting.
Stratos is the operator of Inmarsat’s land earth station facilities in Perth and is a distribution partner of Inmarsat’s services.
We provide comments on the specific questions raised by the ACMA in the consultation document, and request that the ACMA take these comments into account in its future policies towards earth station siting.
Comments or questions on the content of this response should be addressed to:
Mr Paul Deedman
Principal Engineer - Spectrum Regulation
Inmarsat, 99 City Road, London, EC1Y 1AX
or
Mr Tom McKnight
Vice President LES Operations
Stratos, 620 Gnangara Road, Landsdale 6065, Western Australia
Response to questions
1. The ACMA seeks comment on the proposed objectives for the development of a long-term sustainable strategy for the siting of satellite Earth stations and other space communications facilities.
Inmarsat supports in principle the objective of providing a strategic framework for meeting the requirements for satellite Earth stations and welcomes ACMA’s reassurance that “The intention of this paper is not to restrict or regulate the geographical or frequency locations of current or future Earth station deployments”. However, many of the proposals made by the ACMA in this consultation appear unlikely to achieve the stated objective - rather they introduce uncertainty in the use of existing facilities. This is explained further in the answers to the questions below.
Referring to the five principles identified in section 1.1.2, Inmarsat makes the following comments.
Principle 2 is to “Enable and encourage spectrum to move to its highest value use or uses”. Inmarsat has a concern that this consultation appears to assume that all terrestrial services are of higher value than satellite ones and does so without justification, discussion or evidence.
In the case of C-band, the most commonly cited alternative use is broadband fixed and mobile access. However, systems in this band have not been deployed as quickly, or as extensively, as many of the predictions and the long term success of such systems remains highly uncertain. Whatever value can be attributed to terrestrial systems in C-band, would need to be compared to the value from satellite services in C-band, which provide many socially vital functions, not feasible by any other means.
The Inmarsat maritime and mobile communication services provided by the Stratos facilities deliver a number of significant benefits to the Australian people as well as being a commercial enterprise. These should be taken into consideration by the ACMA when considering spectrum allocation and grandfathering options. These services include but not restricted to:
1. Maritime Distress – SOLAS (safety of life at sea).
2. Fleet monitoring for the Australian Search and Rescue Centre.
3. Secure communications for the Australian Defense Force.
4. Fishing Agent Management.
5. Ship position monitoring – in/out of fishing areas, duration and tracking for state fishery departments.
6. Ship position information for national security and maintaining exclusion zones.
7. Provision of services for national security agencies such as ASIO.
8. Aeronautical services for SITA including Air Navigation Services and Flight Deck Management.
We firmly believe that the value of these services is very high and it would not be in the national interest of Australia to have these services provided by facilities in other countries.
In the case of Ku-band and Ka-band, the most commonly cited alternative use is for traditional fixed systems. There is no basis for assuming that use of spectrum by fixed systems is of higher value that the use by FSS earth stations.
Principle 4 is “To the extent possible, promote both certainty and flexibility”. These two requirements can be conflicting, e.g. increased flexibility is typically at the expense of certainty. For satellite services regulatory certainty is vital, due to the long lead times for the development and operation of satellite systems, and due to the requirements for international harmonisation of spectrum use. In bands allocated to satellite services, increased flexibility should not be at the expense of regulatory certainty.
The ACMA identifies two objectives of the proposed strategy, to:
· provide a strategic framework for meeting the requirements for satellite Earth stations and space communications in a sustainable way into the future
· provide options for a pathway to enable spectrum users and assets to move towards this framework.
Inmarsat supports the first objective of meeting the requirements for satellite Earth stations and space communications. However what is “sustainable” and what is “not sustainable” is clearly a matter of debate and is subject to decisions by the ACMA. In the discussion paper, the ACMA suggests that it will implement policies, the consequence of which would be to make earth stations in some locations unsustainable. Inmarsat opposes such policies.
The second objective pre-supposes that the new framework requires spectrum users to move. Inmarsat would be opposed to any forced migration of it services and network. As a minimum existing facilities should be grandfathered for the life of the satellite network.
2. The ACMA seeks stakeholder comment on any additional pressures that should be considered in the context of Earth station siting.
In addition to issues of co-existence with other radio systems, additional considerations in earth station siting include the availability of redundant fibre infrastructure, reliable power supply, secure building and securing suitably qualified staff in remote areas. These requirements may not be achievable in rural areas, or could lead to significant additional costs.
3. The ACMA seeks comment on areas of growth in the satellite industry. Where is the biggest growth expected? Are there any emerging applications for satellite services that are expected to impact spectrum requirements?
The growth in mobile broadband is one of the factors driving the growth in satellite communications. Mobile broadband applications for land, sea and airborne users are driving demand in the Inmarsat network, leading to increased requirements for spectrum in the 1.5/1.6 GHz bands for the service links, and increased requirements for spectrum in the C-band (including 3.4-3.8 GHz) for the feederlinks.
To further meet the demands for mobile broadband, Inmarsat is investing in a new GSO satellite system, “Global Xpress”, which will operate in the Ka-band satellite frequencies. This system will provide mobile broadband communications with data rates considerably in excess of those available today in mobile satellite systems.
Although not directly related to Inmarsat, it is apparent that there is also growth for Ku-band satellite systems, driven largely by the demands for direct-to-home TV distribution.
Hence, the three main commercial satellite communications bands: C-band, Ku-band and Ka-band are all experiencing growth in spectrum requirements for satellite communications.
4. The ACMA seeks comment on the methodology used to establish a benchmark population level below which Earth station operation would be reasonably secure in the long term.
Inmarsat is not well qualified to comment on the calculation of the maximum population of a town that would not require spectrum for terrestrial mobile broadband shared with satellite services. However it should be recognised that there is an enormous uncertainty about the demand for terrestrial mobile broadband. Examination of the traffic demand shown by the ACMA in figure 2.1 of the consultation document shows a cumulative annual growth of between about 50% and 70% between 2007 and 2020. Some industry predictions have suggested much lower figures (24% CAGR to 2015 from Analysys-Mason) while others have suggested much higher figures (102% CAGR to 2015 from Cisco).
Furthermore, it cannot be assumed that there is a need for any additional spectrum for terrestrial mobile in bands shared with satellite systems. Some of the future demand will be met from bands currently unused, such as the 800 MHz band and the 2.6 GHz band. There are also evolving technologies such as femtocells, which achieve very high frequency reuse with existing mobile spectrum, reducing the need and cost required to develop new frequency bands.
With this level of uncertainty, it seems unwise and unnecessary to impose constraints on existing services and applications on the basis of any traffic predictions for mobile broadband.
5. The ACMA seeks stakeholder comment on any additional categories of tools that could be used to address the various pressures on spectrum used by the satellite and space sectors.
The ACMA has identified the need to consider economic tools and planning and technical tools. These tools would not address the societal benefits from the use of satellite communications. For example satellite systems are often the only means of communications between remote countries and are often the only means of communication for users in areas not covered by terrestrial communications. Furthermore, it is necessary to recognise the large financial investments made by the satellite industry in new satellite networks and the associated earth stations.
6. The ACMA seeks comment on using opportunity-cost pricing of spectrum for satellite Earth station licensing based on spectrum denial caused to terrestrial services.
Several administrations use opportunity cost as one element of their pricing strategy and of setting licence fees. This may lead, for example, to lower fees for earth stations in rural areas, where the opportunity costs may be very low. However we are not aware of any administration using opportunity cost as a basis of the forced migration of earth stations, as is suggested by the ACMA in section 3.1 of the consultation document.
In making an assessment of the opportunity cost, it is necessary to estimate the actual stations denied to the alternative application by an earth station. Figure 3.1 in the consultation document gives an example of an area of “spectrum denial”, showing a large geographic area shaded. It is interesting to note that the ACMA suggests that the earth station could be moved to an alternative location using fibre backhaul. However, a similar argument can be made about the “alternative use” in this example – fixed service stations. Fixed links could also be replaced with fibre connections, allowing easier spectrum access for FSS earth stations. It is not apparent why this discussion is based earth stations making way for FS stations, and not vice versa.
The characteristics of the earth station and the fixed links used to generate Figure 3.1 do not seem to be given, nor the other assumptions required to assess the “denial area”. If the area is determined based on the worst case alignment of the FS station, it is clear that the “denial area” could be significantly smaller for the more typical case of FS stations which do not point towards the earth station. Furthermore the “denial area” may not be as large as depicted if, for example, clutter losses due to buildings in the Sydney CBD are included. Hence the “denial area” depicted is most likely the coordination area, where more detailed analysis may allow the operation of FS stations while still sharing spectrum with the earth station.
The “denial area” will probably also vary from earth station to earth station, with, for example, earth stations in areas of natural shielding having smaller denial areas. The ACMA argues that the quantity of spectrum denied by an earth station may be considerably larger than that due to the actual use by the earth station since some of the FS channels partly overlap with the spectrum used by the earth station. This is a direct consequence of the choice of channelling arrangements by the FS rather than a consequence of the use of the spectrum by earth stations and therefore solutions should focus on changes to the FS use rather than the satellite use.
There is no conclusion to the discussion in section 3.2. There is no determination of the number of fixed links denied access from the example earth station and no assessment of the opportunity cost associated with the example earth station. There is also no discussion of how the results for this one example (even if they were complete) could be extended to cover earth stations in general. Consequently, there is no basis presented for concluding that opportunity cost justifies the relocation of this example earth station, or any other earth station.
7. The ACMA seeks information on any additional planning and technical tools that could be used to manage interference into satellite Earth stations and other space communications facilities.
No comment.
8. The ACMA seeks comment on the use of filtering in Earth receive stations and its applicability and usage in interference mitigation.
Inmarsat agrees that that filtering can be used to help prevent interference between systems operating on adjacent frequencies. There are two mechanisms to be considered: firstly, the wanted emissions of the transmitter, which are received on adjacent frequencies from the perspective of the receiver; and secondly the unwanted emissions of the receiver, which are received on the wanted frequencies from the perspective of the receiver. All transmitters, whether earth stations or terrestrial stations could cause interference by both mechanisms, and all receivers, whether earth stations or terrestrial stations could be vulnerable to interference by both mechanisms. Interference by the first mechanism can be mitigated from the use filters fitted at the receiver. Interference by the second mechanism can be mitigated by the use of filters fitted to the transmitter.
Filtering can be a useful tool in avoiding interference, or avoiding the need for guardbands. ITU-R studies, such as those looking at interference from BWA base stations into FSS earth stations[1] have suggested that for adjacent band operations, separation distances ranging from less than 1 km to several tens of km are required, depending on the characteristics and assumptions used. These distances could be reduced from the use of filters. When it comes to receiving earth stations, as explained above, filters could be needed at the transmitting station, or at the receiving earth station. Some regulatory means is required to ensure that potential adjacent band interference from terrestrial stations to earth stations is identified in advance, giving the two parties the opportunity to resolve potential interference before it occurs.