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Erasure codes: next steps

Tomaso De Cola

CCSDS Spring Meeting 2014, Noordwijkerhout, 31 March – 3 April 2014

Recap from last CCSDS meetings

- Erasure codes are a powerful means to provide reliability in case of:- DTE optical links (fade events duration 10-100 ms)- Large propagation delay (Moon+)- RF synchronisation errors because of sun interference

- Architecture perspective:- Erasure coding implemented in a layered way, as an independent

shim layer (EC shim layer)- Particularly promising as complementary reliability measure

implemented below LTP

- Implementation status:- LDPC-based erasure codes with fixed code-rate implemented in ION

(soon also available for version 3.2.0)

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The integrated architecture

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Application Layer (CFDP, AMS, …)

BP

LTP CLA

ENCAP CLA

TCP CLA UDP CLA

LTP

IP

IPoC

Encapsulation Service(EP or SP)

TM TC AOS Prox-1

RF/ optical

Ethernet

Wire

EC shim layer

EC for which services?

- EC intrinsically appealing for telemetry and file transfer applications

- In terrestrial domain, EC particularly promoted for multimedia (A/V) streaming:

- DVB- 3GPP

- Video streaming also available for space communications (MIA wg):- EC could be powerful to make video streaming more robust ( result

from last joint CCSDS DTN-MIA meeting in Fall 2013)- EC could need an ad-hoc code configuration based on A/V codec

used by the streaming application

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Some more thoughts…

- Future plans to enable video streaming in DTN-based architecture consider the implementation and specification of the Bundle Streaming Service (BSS):

- Real-time streaming- The video is played real-time with some erasures, out-of-order

stream bundles are stored in the BSS database but not displayed - Later re-play

- The entire video can be played later when the missing bundles (available in the BSS database) are eventually received

- EC can be used to enable:- Real-time stream with no bundle erasures at the cost of minor delay

(encoding, decoding, buffering for jitter issues)

- Next steps to test ION-EC sw with a (video) streaming application

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Thanks for your attention

01.04.2014 > CCSDS Meeting > Tomaso de Cola