[CESG] SLS Comments to: Response to AI from CESG meeting re FF-CSTS and AOS uplink

Wed May 31 13:42:46 UTC 2017

Dear ALL,
        Here following SLS comments to slides.

Page 2 BACKGROUND
Bullet 1: the question is about what are the allowed coding schemes and 
modulation.
Bullet 2: There not a <perceived gap>, there is a gap. There are no CCSDS 
Standards available for uplink of AOS Frames. As far as SLS know, as of 
today the uplink of AOS Frames is limited to ISS (via TDRSS) and here are 
no interoperability requirements for ISS. 
The coding schemes used for uplink to ISS are Convolutional, Reed-Solomon 
and their concatenation. Those schemes are defined in 131.0-B but there is 
no CCSDS standard allowing their usage for uplink. 
The modulation used for uplink to ISS (via TDRS) are defined in the so 
called <SNIP Agreement> that is only partially part of the 401.0-B 
standard from RFM WG. Of course the modulations are not aware of the kind 
of frames transmitted.
CSS AD Notes bullet 1; No discussion that AOS was designed to be multi 
purpose, however the standardisation available is limited to 
space-to-ground.
CSS AD Notes bullet 2; Please refer to 732.0-B-3 at  
https://public.ccsds.org/Pubs/732x0b3.pdf
Section 1.7  REFERENCES  ittems [3], [4] e [5] are:
[3]  TM  Synchronization  and  Channel  Coding .  Issue  2. Recommendation 
 for  Space  Data  System Standards (Blue Book), CCSDS 131.0-B-2. 
Washington, D.C.: CCSDS, August 2011. 
[4]  Flexible   Advanced   Coding   and   Modulation   Scheme   for   High 
  Rate   Telemetry   Applications. Issue 1. Recommendation for Space Data 
System Standards (Blue Book), CCSDS 131.2-B-1. Washington, D.C.: CCSDS, 
March 2012. 
[5]  CCSDS  Space  Link  Protocols  over  ETSI  DVB-S2  Standard . Issue 
1. Recommendation for Space Data System Standards (Blue Book), CCSDS 
131.3-B-1. Washington, D.C.: CCSDS, March 2013. 
Section 2.1.1 states :   For the Synchronization and Channel Coding 
Sublayer,the set of TM Synchronization and ChannelCoding Recommended 
Standards (references [3], [4], and [5]) must be used with the AOS Space 
Data Link Protocol.
Section  2.4.1 states:   As described in 2.1.1, the set of TM Channel 
Coding and Synchronization Recommended Standards (references [3], [4], and 
[5]) must be used with the AOS Space Data Link Protocol as the TM 
Synchronization and Channel Coding Sublayer specification. 
Those 3 standards are for transmission space-to-ground.

Page 3: CONTEXT DIAGRAM
The technical  diagram is very and probably correct (I did not check it 
carefully).
However I doubt this slide is relevant for CMC as they should be made 
aware of the problem while the diagram addresses how CSSS Area want to 
develop a standard after ALL the relevant (available, in progress, future) 
SLS Standards will be available.
USLP Standard is in progress and with the current formulation will be 
possible for USLP Frames to access the chain for TC Coding. 

Other remark: who decides which subset of coding schemes (see books  [3], 
[4] e [5] in AOS Standard) are to be implemented and which not?
Tis is something C&S WG shall do (if any Agency will propose to look into 
this issue).

Page 4 ANALYSIS
Red path is not according to CCSDS Rules and pertinent to SLS and not to 
CSS.
Definition of new SLS Standards by modification of CSS Book is simply not 
acceptable.

The flow diagram misses the start point that is the proposal from one or 
more CCSDS Agencies to add relevant standards according to their user 
needs.
Again, the point is that there is an absence of specification and 
therefore the Agency/Agencies requesting such capability in CCSDS shall 
identify the desired profiles for Coding and Modulation and propose 
relevant work for the the experts in the C&S and RFM WGs. Only after those 
standard (or Recommended Practices) are made available it will be possible 
to modify the AOS Standard (most likely limited to section 2.1.1 and 2.4).

Page 5 PRELIMINARY CONCLUSIONS
As mentioned, 732.0-B can only be modified after the relevant  standard 
(or Recommended Practices) are available.
No Space Data Link Protocols defines the standards for Coding and/or 
modulation. 

SLS Recommandations
Define what the problem is; i.e. it looks there are no C&S and RFM 
standards to support uplink of AOS Frames
Invite concerned agencies to identify the  C&S and RFM profiles they 
require  to support uplink of AOS Frames.
Once such profiles are identified, it can be verified what is missing and 
relevant Standards or Practices can be defined by  C&S and RFM if 
consensus and resources available

Note that, while it is sure that TM Coding Books are not applicable to 
uplink, it may be that existing uplink modulations already satisfy user 
needs.

Best regards

Gian Paolo & Gilles

From:   "Barkley, Erik J (3970)" <erik.j.barkley at jpl.nasa.gov>
To:     "CESG -- CCSDS-Engineering Steering Group (cesg at mailman.ccsds.org) 
(cesg at mailman.ccsds.org)" <cesg at mailman.ccsds.org>
Date:   30/05/2017 22:56
Subject:        [CESG] Response to AI from CESG meeting re FF-CSTS and AOS 
uplink
Sent by:        "CESG" <cesg-bounces at mailman.ccsds.org>

CESG Colleagues,

Attached please find a preliminary analysis re way forward for FF-CSTS and 
AOS uplink issue that was raised during the San Antonio CESG meeting. Your 
inputs will be appreciated.

Best regards,
-Erik[attachment "d0-FF-CSTS-and-AOS-Uplink-30-May-2017.pdf" deleted by 
Gian Paolo Calzolari/esoc/ESA] 
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