[CESG] FW: OLSG Report Addendum Recommendations for CCSDS

Gian.Paolo.Calzolari at esa.int Gian.Paolo.Calzolari at esa.int
Fri Nov 23 07:29:32 EST 2012

        SLS is going to welcome the twenty additional working groups 
without any problem :o)
OK, jokes apart, here are my CESG-limited comments "at a glance".
Note that I miss background for their choices and clearly some remarks are 
more questions about that background than negative comments.
As well, I can guess that Priority 1 means start now (e.g. according to 
the last roadmap: BoF in 2013, WG in 2014 onward) but would be interesting 
to know the target end for priority 1 as well the expected time frames for 
other priorities.

1.1     It would be good to know how much this independent study would 
affect/prevent future CCSDS activities.
1.2     Not a real CCSDS matter but rather a question for IOAG in keeping 
alive OLSG in parallel to CCSDS WGs.

1.3 row by row:
a) dual wavelength: It looks as a proposal for a reasonable compromise to 
have the configurable part on ground (i.e. more or less what we already do 
for RF, coding, etc.)

b) uplink beacon: I understand this is limited to the uplink needed for 
establishing a downlink connection. In such a sense is OK with priority 1 
while I think that optical uplink will have lower priority.

c) return link modulation+coding - OK for priority 1. Minor comment: I 
would remove "two sets" as the WG should study whether it is possible to 
have a single set or not.

d) VCM ok for lower priority.

e) ACM ok for priority lower than VCM even if one can consider ACM a more 
dynamic VCM (i.e. the difference may be on uplink interaction and 
management issues) .

f) forward link modulation+coding - OK for priority lower than 1, but I 
would like to understand the urgency of requirements for Optical Uplink. 
Which kind of "TC" is really needing very high speed and very high volume 
of data? Could e.g. VCM ma be more urgent than forward link?

g) Studying IOAG Catalogs. In the Spring 2013 Darmstadt Meeting I made a 
presentation to SLS-OCM. You find it here 
 . In that presentation I suggested to focus the initial work on (re)using 
SLE RAF and RCF services to minimize the impact on the "surroundings". 
However, as the Telemetry Optical data rates exceed the terrestrial line 
capacity, those services should be carried out in offline delivery mode. I 
also mentioned that using CFDP to downlink files is an attractive option 
and Optical Communications could be the pushing factor for the full 
implementation or Return File Services in the IOAG sense (i.e. a Service 
that enables a mission to send the contents of a file to a Control Center 
by allowing a Ground Tracking Asset to provide a Control Center with files 
received from a spacecraft). To summarize I think that initially optical 
communications could initially focus reusing RAF, RCF and CFDP (with file 
reconstructed in the station and eventually transferred to control center 
with IOAG Return Frame Service). In the longer run longer frames (as both 
TM and AOS standards limit the frame length to about 2048 octets) should 
be made available and this could even require adapting/creating new 
standards not limited to SLS-SLP. Having said this, I wonder whether this 
item shall really be Priority 1 as the availability could be required 
after the items that have immediate need to get a working optical 

h) meteo data: it looks an issue similar to radio metric etc. Once a data 
format is defined, the exchange could be via file transfer for which cross 
support service are expected sooner or later. I think that there would be 
no real time issues as meteo events are normally slow.  I wonder whether 
it could have less  priority (e.g. 1 and 1/2 :o) but this is just a 

i) standard practice for automatic retransmission: this is puzzling me. 
Automatic retransmission is normally part of a protocol and not a 
practice. I need to know/understand more, but should be coupled with the 
definition of new optical protocols mentioned above in the item for " 
Studying IOAG Catalogs". In such a sense Priority 2 looks OK.

j) service management updates: Priority 2 looks OK to me but CSS may 
comment on resources.

k) best practices. This last bullet is very wide and could mean several 
magenta books. We  need to know/understand more but is is OK not being 
priority 1.

Summarizing: the items given priority 1 look OK to me  with the exception 
of developing "immediately" optical communication-specific protocols that 
may be unfeasible/risky for resource and schedule issues.
As well I would need to better understand/know the use cases for optical 
forward link.

With respect to your racing comment, indeed SIS also has a horse in this 
race specially for CFDP, LTP and possible interaction with SLS-SLP for a 
new longer frame structure.
CSS-SM will also be impacted while CSS-CSTS should initially be affected 
only for the planned work on file transfer while in the long run "optical 
communication-specific protocols" could have a domino effect.
For SLS however I think it will be more similar to Greyhound racing where 
we have to play the role of the lure :o)   

This is all for my initial analysis based on Bernies' fast report.

I wish you all a nice week end.

"Hooke, Adrian J (9000)" <adrian.j.hooke at jpl.nasa.gov>
CESG <cesg at mailman.ccsds.org>
22/11/2012 19:11
[CESG] FW: OLSG Report Addendum Recommendations for CCSDS
Sent by:
cesg-bounces at mailman.ccsds.org

Quite a lot of work to do here, which mostly falls in Gippo?s area. Gippo: 
do you generally agree with the proposed priorities? However, I think that 
SIS also has a horse in this race (e.g., ?the CCSDS should develop 
standard practices for each scenario (e.g., LEO, GEO, Lunar, L1/L2, deep 
space) that will enable automatic retransmission? since LTP is a 
From: Edwards, Bernard L. (GSFC-5600)
Sent: Thursday, November 22, 2012 6:50 AM
To: sls-com at mailman.ccsds.org
Subject: [Sls-ocm] OLSG Report Addendum Recommendations for CCSDS
This is Bernie Edwards from NASA again.  I just wanted to let you know 
that the Optical Link Study Group met in Darmstadt, Germany last week and 
worked on the addendum to the OLSG report sent to the IOAG earlier this 
year.  Once the report is finalized, I will be able to share it with this 
group, but in the meantime, I did want to share the recommendations that 
will be presented to the IOAG at their next meeting at NASA?s Kennedy 
Space Center in early December.  Guidance for a new CCSDS working group 
can be found in Table 1.3 below.
If you have any questions or concerns about these recommendations, please 
let me know and I can get them to the group leaders.
Bernie Edwards
1.1       Action for all Agencies
Recommended Action for All Agencies
The space agencies should conduct a rigorous detailed study independent of 
the CCSDS to determine if there are ways of accomplishing beaconless PAT, 
as this would also facilitate a solution to the eye safety issues.
1.2       Actions for the OLSG
Recommended Actions for the OLSG
The OLSG should continue the dialogue with ICAO, with the goal of 
accommodating optical space communications within the ICAO laser safety 
The OLSG should continue the dialog with the NASA JSC Space Medicine 
Office to discuss the implications of the revised eye safety calculations 
performed by the OLSG.
1.3       Standardization Guidance for the CCSDS
Recommended Standardization Guidance for the CCSDS
The CCSDS should study the possibility of dual wavelength terminals in the 
event that a single wavelength is not achievable. A common optical 
interface should be defined that would allow one agency?s back-end 
equipment to be connected to another agency?s optical front-end
The CCSDS should standardize the uplink beacons and associated acquisition 
The CCSDS should develop two sets of standards for modulation and coding 
for return links to deal with the low and high photon density domains.
The CCSDS should develop standards for combinations of modulation and 
coding for channel-dependent effects (e.g., those caused by elevation 
angle and atmospheric conditions). VCM standards should be prepared.
The CCSDS should develop standards for combinations of modulation and 
coding for channel-dependent effects (e.g., those caused by elevation 
angle and atmospheric conditions). The CCSDS should develop ACM standards.
The CCSDS should develop two sets of standards for modulation and coding 
for forward links to deal with the low and high photon density domains.
The CCSDS should conduct a study to confirm that IOAG Service Catalog 1 
and IOAG Service Catalog 2 can be used, and recommend an association of 
the optical physical modulation and coding layers with the existing higher 
protocol layers. If the existing protocols are considered insufficient, 
then CCSDS should develop optical communication-specific protocols.
The CCSDS should develop data exchange standards for optical communication 
forecasts and meteorological data from ground sites. The CCSDS should 
reuse existing standards (e.g., BUFR, GRIB, NETCDF) from the 
meteorological community when possible.
The CCSDS should develop standard practices for each scenario (e.g., LEO, 
GEO, Lunar, L1/L2, deep space) that will enable automatic retransmission.
The CCSDS should review the service management standard and identify areas 
that must be modified to accommodate optical communications and develop 
the necessary amendments.
The CCSDS should develop best practices for the systems engineering of 
optical communication links for missions, including practices for 
meteorological databases, link budget, compatibility testing, and 
terminology/system decomposition.
From: Edwards, Bernard L. (GSFC-5600) 
Sent: Thursday, October 04, 2012 11:10 AM
To: sls-com at mailman.ccsds.org
Subject: OLSG Report Submitted to the IOAG in June
Hi Again!
I was told the e-mail list is working, so I wanted to send out some more 
Attached is the OLSG Report that was submitted to the IOAG in June.  I?ve 
also attached the presentation used.
The OLSG is busy updating the report with more analysis done ? mostly 
operational issues such as impact of clouds, airplanes, laser safety, etc. 
 The OLSG is also working hard on recommendations for what parameters 
should be tackled by CCSDS (e.g. modulation; coding; point, acquisition, 
and tracking approaches, etc). 
I?m going to ask for permission to send out the new outline for the new 
final report from the OLSG co-chairmen and send that along as soon as I 
can.  If you see any issues with the interim report, please let me know or 
another person on the OLSG so that it can hopefully be addressed in the 
new report being worked.
From: Edwards, Bernard L. (GSFC-5600) 
Sent: Thursday, October 04, 2012 11:01 AM
To: sls-com at mailman.ccsds.org
Subject: Update on the IOAG Optical Link Study Group
Hello OCM SIG Members!
This is Bernie Edwards from the NASA Goddard Space Flight Center.  I 
wanted to test that this mailing list is still good and reaches the 
members of the OCM-SIG. 
Assuming this works, as all of you know, there is no OCM-SIG meeting this 
fall at the CCSDS meeting in the United States.  That was decided back in 
Darmstadt because we wanted to wait and see what the IOAG?s Optical Link 
Study Group was going to recommend.  The Optical Link Study Group (OLSG) 
made several recommendations to the IOAG and was supposed to have 
completed its work, but the IOAG gave it more things to study.  The Study 
Group is working on new recommendations to be delivered to the IOAG again, 
and some of those recommendations include things the CCSDS will be asked 
to work on.  NASA is proposing to use the OCM-SIG to do the work within 
the CCSDS.  Thus I wanted to test this e-mail list.
I will be sending out more information from a NASA perspective once I 
confirm that this list is working!
Bernie Edwards
Bernard L. Edwards
Chief Communications Systems Engineer
Electrical Engineering Division (Code 560)
NASA Goddard Space Flight Center
(301) 286-8926
E-Mail:  Bernard.L.Edwards at nasa.gov
"Dream - Believe - Dare - Do"
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