Skyplex is a new processor that allows a stream of multimedia information such as video, audio and data to be packaged on board a satellite. Traditionally, the various multimedia signals would need to be conveyed through standard communication networks to a ground multiplexing centre where they are combined into a single high-rate multi-programme stream and transmitted to the satellite. Thanks to Skyplex, the satellite can instead be accessed directly, broadcasting
is greatly simplified and costs are reduced, so that many more broadcasters and service providers will be able to make use of satellite systems.
The first Skyplex system is mounted on board the Eutelsat Hot Bird 4
satellite that was launched on Ariane Flight 106, 27
February.
Any television production facility, radio station or Internet provider
can directly access the satellite: a system the size of a low-cost
satellite news-gathering station (typically a 1.8 m dish and a 50 W
transmitter) is sufficient to uplink to the satellite. The Skyplex
processor on board Hot Bird 4 demodulates the incoming low-rate
signals and re-combines them into a single, high-rate multi-channel
digital broadcast signal which is transmitted directly to users' homes.
Transmission is fully compliant with the existing European digital
television standard and therefore the Skyplex signal is
indistinguishable from a conventional Direct-To-Home signal and can
be received by any standard digital TV receiver.
Skyplex payloads are being mounted on Eutelsat's Hot Bird 4 and
Hot Bird 5 satellites, the latter scheduled to be launched this summer.
The Skyplex processor can assemble six uplink carriers with a net bit
rate of 6 Mbit/sec each into a down-link stream of 36 Mbit/sec. The Hot
Bird 5 version can also accommodate lower bit rates, down to 1 Mbit/sec,
using advanced time division multiple-access techniques.
The Skyplex system is the result of a cooperative venture between
ESA and Eutelsat. The first model of the Skyplex payload has been
developed under an ESA contract. The Hot Bird prime contractor Matra
Marconi Space (France-UK) has been responsible for the satellite
interface whilst the payload prime contractorship was awarded to Alenia
Aerospazio (I), with Alcatel Espacio (E), Mier Comunicaciones (E) and
AME Space (N) as sub-contractors. The first model of the ground
facilities has been developed by Newtec (B).
The Skyplex programme is an example of how ESA, in partnership
with industry and operators, aims to develop Europe's satellite
multimedia market. The Skyplex programme is also an example of
how success-oriented cooperation with industry leads to very short
time-to-market initiatives (less than 20 months from contract signature
to launch).
In its recently launched multimedia activities, ESA is negotiating the
development of a second-generation Skyplex processor which will be
designed to reduce costs and to provide new Internet-ready functionality
to cope with interactive multimedia communications. This next
generation will be available in late 1999.
