SATMODE is a set of technologies originally developed for

interactive TV Interactive television is a form of media convergence, adding data services to traditional television technology. It has included on-demand delivery of content, online shopping, and viewer polls. Interactive TV is an example of how new information ...

and based on an always-on return channel via satellite designed for ultra low-cost feasibility. Although no SATMODE network has been deployed up to now for interactive TV, the SATMODE technology is used in the

ASTRA2Connect SES Broadband (previously ASTRA2Connect) is a two-way satellite broadband Internet service available across Europe, which launched in March 2007, and uses the Astra series of geostationary satellites. SES Broadband is owned and operated by SES ...

two-way satellite broadband Internet service available across Europe.

Purpose of the technology

SATMODE is an interactive TV solution via satellite, targeting the mass-market through consumer products. SATMODE supports services to the viewer, like the following ones: * Interactive advertising * Betting * Communication: Chat, SMS, e-mail * Tele-Voting, Polls, Play-along, Quiz * Games: standalone or multiplayer * Home Shopping * Personal Data Consultation / banking * Walled Garden Internet Services SATMODE also supports features allowing the technical management of the iTV platform: * Enhanced conditional access * Audience metering * Statistics gathering * Hard disk drive content management The system is scalable up to the complete DTH population and is designed to minimize the terminal cost.

Modem Layer

The modem layer is specified by a CENELEC standard (EN50478). The system flexibility allows SATMODE to be used in extreme scenarios by adjusting the modem parameters: * Very power limited scenarios (it’s the case for most VSAT Ku-band satellites) * Aggressive multi-beam

satellite space segment The space segment of an artificial satellite system is one of its three operational components (the others being the user and ground segments). It comprises the satellite or satellite constellation and the uplink and downlink satellite links. Th ...

allowing to increase the return channel speed for a given translit power To reach the flexibility goal and nevertheless keep full interoperatibility of terminals, SATMODE uses a fully specified waveform toolbox. The choice of

constant envelope Constant envelope is achieved when a sinusoidal waveform reaches equilibrium in a specific system. This happens when negative feedback in a control system, such as in radio automatic gain control or when an amplifier reaches steady state. Stea ...

modulations is made to minimize the terminal cost. Thanks to this property, very low cost outdoor units (

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) operating at full saturation and in non-linear mode can be used. Moderate bit rates allow to use very low power transmitters (typically 100 mW), keeping the cost compatible with the mass-market. The selected access scheme --

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-- is efficient on iTV traffic and very easy to scale up to a very high number of terminals only sending a few packets from time to time. The building blocks of the SATMODE toolbox are: * Binary or quaternary CPM * Programmable phase filter for CPM modulations (

GMSK In digital modulation, minimum-shift keying (MSK) is a type of continuous-phase frequency-shift keying that was developed in the late 1950s by Collins Radio employees Melvin L. Doelz and Earl T. Heald. Similar to OQPSK, MSK is encoded with b ...

being a specific case) * Flexible Turbo or Turbo-like * Programmable interleavers (3) * Programmable constituent codes with bypass possibilities (2) * Programmable Unique Word structure * Tables extraction from a DVB TS (DVB-S or DVB-S2 broadcast) All the parameters are sent by the HUB through DVB tables, even allowing changes during operation: * FCT: Sprectrum organisation in Carrier Groups * FAT: Spectrum Allocation to services Signalisation information sent to specific terminals is also embedded in DVB tables (SMT tables). The terminal is fully defined: it must be able to play the complete waveform space. The HUB is in the

ground station A ground station, Earth station, or Earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft (constituting part of the ground segment of the spacecraft system), or reception of radio waves f ...

. The HUB usually only implements one scheme and sends the tables to the terminals to instruct them to play that scheme.

SATMODE Project

The SATMODE development project has been funded at 50% b
ESA

References

* ES

Retrieved Aug. 28, 2005 * SES-ASTR

Retrieved Aug. 28, 2005 * Newte

External links

ASTRA2Connect website
Satellite television