PAGE CONTENTS
Objectives
Thales Alenia Space started developing its DVB-RCS satcom solution in 1999. The first generation of product featured a DVB-S forward link and RCS return link. It has been deployed commercially since 2003. This development was supported by ESA through the DOMINO 2 and Dionisos 2 programmes. The evolution of the DVB-RCS, making way to the new DVB-S2 standard early understanding and implementation, started under the DOMINO 2 umbrella. This new waveform resulted in a drastic improvement of satellite communication spectrum efficiency.
The objective of the DSL in the Sky project has been to develop the new generation of Satcom solution, implementing the fully updated DVB-RCS / DVB-S2 standard, including advanced features such as Adaptative Coding & Modulation (ACM), Dynamic Rate Adjustment (DRA), or Satlabs QoS. The target development approach focused on high integration and flexibility.
Another ambition of DSL in the Sky was to build a truly interoperable solution. To this purpose, the DSL in the Sky programme, complemented by national validation initiative, was built to work with terminals from different suppliers.
Yet, in order to make sure of the availability of a terminal implementing all advanced features such as ACM, the programme included a full terminal development activity. ACM allows to increase drastically the system capacity, taking into account the specific situation and transmission conditions of each user.
This second major release (hence R2) of the A9780 (DSL in the Sky product number), bringing drastically better spectrum efficiency, targeted a fairly ambitious market position. Commercial targets initially included a wide range of segment: professional, as well as prosumer and consumer markets. The focus is now more on professional and high end areas, including defence and governmental systems and solutions.
Challenges
Technical issues: A major challenge was to build a forward link matching the complexity of the new DVB-S2 standard: flexibility in coding, modulation, rates, all processing being done fast enough, on high performance but reasonable cost machines.
The development of the terminal faced the use of the first 2 ways ACM capable chipset (ST 900). More globally, the development of a new satcom solution, reaching the market in time, with high flexibility and modularity, capable to release early product delivery, has been an industrial and organisational challenge. The Satcom R2 solution is a software intensive product, with high versatility potential.
Plan
The DSL in the Sky “R2” project plan has been set-up by Thales Alenia Space with the following rationale:
- Built upon the background experience and lessons learned from the first release deployed “R1” of DSL in the Sky, (in particular: management sub-system, QoS, operational requirements,…),
- Taking the opportunity of a technical gap (DVB-S2) to introduce a more integrated product, based on an homogeneous hardware architecture (servers) and plug-in modules approach, resulting in a cost effective and flexible product line,
- Leveraging on the Burst Mode Demodulator development project run by TAS Belgium, allowing to develop a full return link subsystem with leading edge performances, including high performance real-time encapsulation and resources management algorithms,
- Addressing development of both hub and terminal, aiming from the start at a very ambitious feature set (full ACM included).
From these starting lines, TAS has gathered the following development team.
On the Hub side:
- Alcatel-Lucent developed the Forward link Transmitter, a card to be plugged in the FLSS server,
- TAS Belgium supplied BMD boards, and contributed to the development of the access control sub-system,
- TAS France handled all the system design and the major part of the developments, as well as the whole subsystem and system integration, validation and certification.
On the terminal side:
- Spacebridge lead FPGA based preliminary bread boarding of an ACM card,
- Amesys was in charge of the terminal Modem, to be plugged into the SNT,
- The server (Sat-IP Box) hosting all the management and network functions of the terminal a well as the modem board, was developed by TAS France,
- TAS lead the whole terminal development, and ensured the whole integration, up to CE certification of the product.
Current Status
The project started in 2004, and is now completed.
The pictures below show equipment resulting from the DSL in the Sky programme. It includes compact mini-hub (left), standard hub (easily scalable to large size networks), and samples of operating screens. Several types of terminal (3 suppliers) matching the DVB-RCS standard have been validated over the system.
The gateway development was completed in 2008, while the SNT terminal development was completed in 2009. 60 hubs and 5000 terminals (of which 150 SNTs) were deployed as of 2010.
The product line was augmented, in parallel with the DSL project, with a capacitive return link solution (HDR, for High Data Rate), allowing to combine the RCS product architecture with 2-ways links, up to 40Mb/s.