DTP NG project deals with the development and qualification of the next generation of Digital Transparent Processor (DTP) based on 28nm ASIC and optical high speed serial links technologies. Such DTPs will be able to process up to 2500 MHz useful band per access and to present high modularity for offering more than 360 GHz routing capacity compatible with applications ranging from FSS/BSS, HTS & V-HTS needs.
The main function of the DTP is to perform transparent and flexible routing between input and output RF ports in C band with a complete flexibility in frequency plan.
The keys drivers of DTP development are linked to the introduction of new technologies needed to reach the overall performances, mainly :
- 28 nm FDSOI ASIC technology allowing to implement both ADC and DAC functions within the ASIC.
- Optical links allowing to speed up communication between DTP modules and to drastically reduce the harness complexity.
To best answer the satellite operator’s expectations, payload integrating a digital core based on Digital Transparent Processor (DTP) is very promising whatever the targeted final applications (mobile applications, individual fixed access through VSAT, backhauling, …). Indeed, when translated into high level mission requirements, those various services and applications are leading to very similar needs at operators level :
- Capacity to allocate the adequate capacity per beam along satellite service life according to market evolution without oversizing ground infrastructure (number of Gateways, …),
- Progressive deployment of Gateways and Services,
- Capacity to connect different Gateways to the same User beams,
- Capacity to adapt satellite capacity to daily variation of traffic for an overall system optimisation,
- Capacity to tune the frequency resources allocation to beams
New generation of DTP able to process up to 360 GHz offers a real improvement for the new generation of highly capacitive broadband Satcom solutions. Through the ability to digitally process the whole band implemented over the service area, this new generation of DTP enables a large field of possibilities to operate those satellites by fine tuning of frequency allocation to beams and taking full benefits of highly versatile routing capabilities between gateways and user-beams.
The main features of new generation DTP unit are as follows:
- High capacity per input/output for new generation of processor
- Up to 2500 MHz digitalized bandwidth per input/output port
- Modular switching for routing and targeting high capacity
- Full routing capacity – no blocking
- More than 360 GHz capacity targeted for HTS & V-HTS application
- Multiple functions offered
- Channel filtering with channel to channel isolation greater than 30 dB
- Classical channel gain control in FGM and ALC mode
- Input and output power measurements with spectrum analysis capability
- In-band response correction (gain and group delay)
- 2 possible solutions for command/control
- Through classical satellite TM/TC link – still implemented to perform all types of command/control
- Through a high speed link dedicated to Telecommunication channels command/control
- High performance demultiplexing and multiplexing algorithm
- SNIR > 36 dB – 38 dB objective
DTP architecture is based of 5 functional blocks :
- Reception function in charge of input signal analog to digital conversion. It includes : RF input interfaces, Analog to Digital Conversion stage, digital processing, a reference clock interface, TMTC interface and power supplies.
- Routing function in charge of routing data between Reception and Transmissions functions. It ensures non-blocking and full connectivity even when broadcast or multicast of input channels is required. It exchanges commands (incl. hardware or routing configuration) and telemetry with TMTC function as well as Reception and Transmission functions.
- Transmission function in charge of output signals Digital to Analog conversion. It includes : a final stage of digital processing, the Digital to Analog Conversion stage, RF output interfaces, a reference clock interface, TMTC interface and power supplies.
- TMTC function in charge of handling TMTC interfaces with the payload as well as DTP hardware and software (boot, applicative, routing) configuration.
- Clock distribution function : distributes an external reference clock to all Reception and Transmission functions to ensure synchronization of conversions stages and corresponding digital processing.
Spaceflex DTP project plan is defined as follow :
Preliminary design conception
- DTP engineering activities: electrical architecture, mechanical definition, preliminary analysis and budgets.
- Breadboarding of elementary functions (RF functions, DCDC….)
Detailed design activities
- Detailed design and analysis of all module boards, mechanical and thermal design
- 28nm ASIC specification, architecture, design , manufacturing , tests and flight model qualification
- Test Bench development, integration and tests
- Onboard Software development, validation, integration and test
- Manufacturing, assembly and tests of a 8x8 EM DTP,
- Manufacturing, assembly and tests of a 8x8 EQM DTP,
In parallel, all standard reviews (PDR/CDR/MRR/TRR/TRB/QR) associated to product development lifecycle are covered by the project activities.
To date, Spaceflex DTP development phase is completed. Associated key technologies (28 nm ASIC, optical links, mounting processes, thermal management…) are fully qualified. A (8 inputs x8 outputs) Engineering Model has been manufactured and successfully tested. The Qualification Model is fully integrated and currently under qualification tests. On board Software is validated and qualified. In parallel, several flight models (up to 120x120) are in production.