Dear,
We are writing to you today to provide you with information about the critical communication services
that [company] is providing using satellite transmissions in C-band frequencies (3400-4200 MHz
downlink and 5850-6700 MHz in the uplink). {Brief company description as introduction: e.g. Company is
a VSAT Service provider in [country] providing connectivity via satellite throughout [region]}.
As you are aware, leading up to the World Radiocommunication Conference 2015 (“WRC-15”),
organized by the International Telecommunication Union (“ITU”), various groups, including the
terrestrial mobile industry, are lobbying heavily for additional spectrum below 6 GHz. If allowed to
operate in the satellite C-band, terrestrial mobile services will severely disrupt important services
currently delivered by satellite. Because you as a [regulator/ministry] will be making important
decisions about the spectrum that we rely on to satisfy end users’ needs, we thought it necessary to
provide you with information about the extensive usage, nature, and criticality of the services we
provide in C-band.
Service Provided in [Country/Region] via Satellite
{Please describe the services that your company provides and the impact these have for your country and
your region: Information could include the following:
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Region, countries and/or cities/areas to which services are being provided,
Number of end-users or viewers, number of sites connected,
Amount of bandwidth in C-band,
Types of services and applications being used (e.g. broadcasting, cellular backhaul,
connecting schools, hospitals, corporations, etc.)
Any socio-economic or direct economic benefits, including jobs dependent on these Cband services,}
Characteristics and Advantages of C-band
[company] relies heavily on C-band because it has a number of advantages over other frequency bands,
such as Ku- or Ka-band. These advantages include:
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The large geographic coverage area of C-band satellite beams allows for whole regions or
continents to be connected – resulting in a very cost-effective communications network. For
example, one of our services connects [country] to numerous countries throughout [Latin
America/to North America/to Europe - complete as appropriate] – all within the same satellite
beam.
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C-band is essentially resistant to rain fade. While services in higher frequencies sometimes
experience degradation of their signal, services provided in C-band offer extremely high
reliability, even during heavy rain.
Due to its longstanding good experience with and dependence on C-band, [company] has made a
considerable investment into developing an overall network (ground infrastructure, satellite
connectivity, and remote equipment) that is heavily reliant upon, and communicates with, C-band
satellites.
Interference is a Problem
Satellite receivers are extremely sensitive devices because they are designed to receive extremely lowpower signals from satellites located in space 36,000 kilometers above the equator. Satellite services
have co-existed with terrestrial microwave links from fixed points for many years, primarily because of
microwave’s use of highly directional antennas/dishes. By contrast, many of the newer applications
which are seeking to utilize C-band spectrum, such as mobile or nomadic terrestrial wireless systems,
emit signals from many locations and in all directions simultaneously. This transmission mode, coupled
with the levels of power requested for such operations, can easily interfere with satellite receivers.
In some countries where regulators have allowed terrestrial wireless services to use C-band, there have
been massive interruptions of satellite broadcasting services, affecting hundreds of millions of viewers.
Satellite broadcasting operations in Bahrain, Bolivia, Tanzania, Hong Kong, the U.S. and other nations
have been negatively affected.
The interference caused by terrestrial wireless systems is not limited to same band operations. Out-ofband interference received from terrestrial wireless services in adjacent bands is also a problem; high
power signals from wireless systems in an adjacent band are sufficient to make it impossible for
sensitive satellite receivers to operate in an adjacent band. Thus, terrestrial mobile deployment in just a
part of the C-band would negatively impact satellite services.
Sharing Studies
Various ITU technical studies have confirmed that separation distances in the tens and hundreds of
kilometers are required to protect satellite receivers from terrestrial mobile services if the latter were
allowed to operate in C-band. Such large exclusion zones around every satellite earth station would
render any terrestrial mobile service in this band economically unfeasible for wireless system operators.
Questionable Need for Additional Spectrum for IMT
While no one disputes that mobile data traffic is increasing, mobile operators should be encouraged to
first improve the network density and efficiency within their existing spectrum before asking for
additional spectrum which is already extensively used by other services. For example, large scale
switchover by wireless operators to small cell system architecture would dramatically increase network
capacity in wireless systems’ existing frequency bands. Similarly, technological advancements such as
MIMO (multiple-in-multiple-out) can increase network capacity without any increase in spectrum.
Additionally, one of the large drivers behind the increase in terrestrial mobile data traffic is video.
However, much of the video on mobile devices and tablets is consumed in Wi-Fi-connected areas (the
home, the office, the public library or airport), and it is not clear that cellular networks need increased
bandwidth for this purpose.
The above factors, when taken together, would seem to obviate the need for identification of additional
spectrum for wireless systems – contrary to what wireless operators and their supporters claim.
Conclusion
[Company] is only one of the many users of C-band providing services in [country/region]. We hope that
the information provided herein gives you a glimpse of the multitude of services and applications
provided via satellite. C-band is the lifeblood of many of these services. Please keep the usage and
importance of C-band satellite services in mind as your administration is preparing for WRC-15.
We hope that you found the information provided helpful. Please do not hesitate to contact us if you
require further background information.
Sincerely,