The boom in data communications that started in the
1960s is a long way from abating. The early and mid 1980s
will see a new generation of digital data transmission services
come into operation that could change the ways business is
conducted. "Information management and exploitation will
change the fabric of society", according to Nicolas Mokhoff,
Associate Editor of IEEE Spectrum Magazine. Manipulated
by microelectronic, computer, radio and other electronic
disciplines, information has become a vital commodity at
the trade exchange. But unlike the prices of most commodities
today, the price for exchange of information is decreasing
because of electronics. One of the principal contributors
to this decrease has been the geosynchronous telecommunications
satellite, due to rapid advances in space and communications
technology and the resulting cost-effectiveness achieved
in applying that technology. Advances in IC technology have
made digital telephony an equal partner with analogue. The
inherent advantages of digital reliability, low cost and
smaller packaging are prompting Telecom to phase out present
equipment and expand new services with a digital hierarchy,
such as the Digital Data Service being introduced in late 1982.
Services employing advanced satellite and microwave
technology, and also the existing and upgraded telephone
systems, will have at least two things in common: they will
transmit and switch data digitally, including coded speech,
and the data will be transmitted in bursts. The technology
that may expand fastest is the second generation of
commercial communications satellites. Pier Bargellini, a
senior scientist at Comsat Laboratories, says that "without
the use of satellites as reflectors for source and data
channels, television signals
could not be shared by remote
areas, long-distance telephone services would be constricted
and the data exchange for the business world would be
hampered."
Changes in the communications industry have been so
dramatic (particularly with regard to satellites) that
government bodies (including the Australian Federal Government)
have been forced to reexamine long-standing communications
practices.
In October 1979 the Minister for Post and
Telecommunications announced the Governments decision that
it would be in the national interest to establish a
communications satellite system for Australia. At that time,
the Minister also announced that, a Satellite Project Office
would be established within the Postal and Telecommunications
Department to set in train the planning activities necessary
for the introduction of the system. The SPO has been
operational within the Department since late 1979, and
2.
consultation of system service requirements in particular
has involved liaison with a broad spectrum of interests
including Commonwealth departments.
Figure 1 of Appendix A testifies to the
Australian Government's policy of supplying outback
communities with improved communications services
(including television) by using satellite facilities.
Very little is known about the benefits and needs
(in Australia) that a data communications satellite
system might be able to fulfil, including those needs
of the Department of Social Security. This is mainly
due to the lack of specific details about the final
configurations and costs of the separate satellite services,
which wont be known until late 1981.
This paper is , therefore, an initial but detailed
examination of the hardware and software subsystems which
constitute a domestic telecommunications satellite system.
More specifically, the paper considers the on-board
equipment of a communications satellite (the space segment -
including satellite launch and orbit characteristics, and
signal propagation delay and attenuation), and the earth
stations (the ground segment - including signal modulation,
multiple access and computer application considerations);
all as dictated by Australian geographical, economic and
communications traffic density characteristics. The paper
then considers some of the possible methods Australian
corporations and government departments may adopt to
utilise satellite communications links, particularly
for data communications.
A second paper will re-examine the situation by
applying the specific facilities and costs, when they are
known (these will be announced by the Satellite Project
Office after contracts for the space and ground segments
have been let), to a large, low-traffic, interactive
multipoint network such as that of the Department of
Social Security.
| Identifer | oai:union.ndltd.org:ADTP/218811 |
| Date | January 1981 |
| Creators | Burdlmayr, G. R., n/a |
| Publisher | University of Canberra. Information Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | ), Copyright G. R. Burdlmayr |
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