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Optimised CCSDS protocol stack for high data rate

Programme Reference
Prime Contractor
Start Date
End Date
The objectives of this activity are to identify potential protocol performance issues for on-board and on-ground implementations, define required protocol improvements and provide software and hardware prototypes of on-board and on-ground implementations for re-transmission of lost data. The activity shall prepare the standardisation of an Automatic Repetition Request (ARQ) scheme for optical direct-to-Earth links in order to replace the proprietary solutions currently in use
Upcoming Earth observation missions will feature very high downlinks rates over less reliable links (K-Band / Optical). Supporting such high rates may require the adoption of new standards like the Unified Space Data Link Protocol allowing larger frame sizes and the re-transmission of data segments like done in the CCSDS LTP protocol or private ARQ schemes. The less predictable nature of optical downlinks makes it even more necessary to seek into alternatives like a more networked communication paradigm.
The activity aims to solve the following needs:
    • High data rate downlinks (up to 10 Gbit/sec) for less reliable communication links (K-Band / Optical) for Earth Observation missions
    • Networked communication for LOP-G (Bundle Protocol, LTP, USLP are in the communication requirements for LOP-G) and (commercial) optical ground station providers (from a pass-based to a data-volume-based ground station scheduling approach)
    • Standardised optical direct-to-Earth communication (standardised ARQ protocol instead of the current proprietary protocols).
The activity shall consist of the following tasks:
    • Define communication protocol stacks for high-rate payload data downlink including configuration of the individual protocol layers. This shall take typical optical and K-Band scenarios into account (with/without uplink), typical link characteristics (scintillation, cloud coverage, weather effects) and variable coding amp; modulation (VCM).
    • Identify shortcomings in applicable CCSDS standards wrt to performance of on-board (hardware) and on-ground (software) implementations, define alternatives, simulate and validate those.
    • Analyse whether CCSDS LTP or a variant thereof could be a standardised alternative for the private ARQ schemes currently in use in optical direct-to-Earth links based on the uplink beacon.
    • Provide prototypes of on-board (FPGA) and on-ground implementations of an open ARQ scheme. Prototypes should make use of available implementations and IP cores such as LTP implementation (ground) and the USLP encoder/decoder prototype (on-board). ;
    • Implement the qualification model integrating the prototypes above.
    • Validate the open ARQ scheme with the on-board and the ground prototypes with simulated link characteristics. ;
    • Provide input for further standardisation and guidelines for performant implementations;
Application Domain
Generic Technologies
Competence Domain
8-Ground Systems and Mission Operations
Initial TRL
Target TRL
Public Document
Executive Summary
Final Presentation