[Sls-rfm] RFM inputs (batch #3)

[Marco Lanucara]

Dear Dennis and all,

I eventually found the time to have an in-depth view of Wai and Wing input (below referred as technical note, TN for short).

I would like to provide a feedback for your consideration when incorporating the TN as annex of the green book (CCSDS 413.1-G-2 Simultaneous Transmission of GMSK Telemetry and PN Ranging).

The first point is of a kind of editorial nature.

Whan I created the first annex, I made an effort to adhere, as much as possible, to the terminology and conventions described in the target book, for example through the re-iterated use of PT Ts/No, omnipresent in the book, in formulas and figures.

At the moment I think this goal is not achieved in the TN, which makes extensive use of other quantities in formulas and plots, and it runs a bit “independently” from the future container. It could be difficult for a reader to do all required translations to make the considerations applicable to his/her case.

My suggestion here would be to take a bit of effort in aligning the treatment to the green book.


The second point is about a complementarity which I see between this TN and the input I had previously sent.

Whereas I tackled primarily the need to have a structured process for establishing proper configurations (a need which emerged during these investigations), especially with simultaneous presence of high Doppler dynamics and low signal to noise, the goal of the TN is of a more explorative nature (in my view), with an investigation path involving multiple architectures and combinations of successful/failed attempts.

I think this complementarity could be made more evident, e.g. by clarifying in the TN, maybe in the conclusions, that different (present or future) implementation and algorithms could lead to different results, e.g. in terms of supportable gammas.


The third point is of a technical nature. It is related to an identified threshold for supportable gamma with GMSK BTs = 0.25. As clarified in the past, and also reflected in the annex I produced, supportability of a configuration is also strongly depending on the amount of phase jitter (linked to the SNR), in addition to Doppler dynamics.
Figure 2 in my annex is absolutely clear on this point.

It is numerically clear that the behaviour of the configurations which are claimed to confirm the gamma = 0.02 threshold in the hardware validation section is dominated by the amount of phase jitter. By reducing such amount it is certainly possible to exceed such threshold, as later acknowledged even in the TN.

So in summary, I find the following sentence misleading, it could maybe be revised together with similar statements in the conclusions.
“The 𝛾 = 0.02 inoperability threshold was confirmed. We must caution that this conclusion has a caveat. The architecture of the hardware is not identical to low-SNR MAP used in this analysis. It is more related to the high-SNR MAP [10]. The fact that both architectures arrive at the same inoperable point leads one to conclude that the result is fundamental.”

Other than the above, I find the TN informative, and I acknowledge the immense effort that was involved (I can say symmetrically spent on ESA side)

I hope the above is useful, and as usual I remain available for any question.

Regards

Marco


From: SLS-RFM <sls-rfm-bounces at mailman.ccsds.org> On Behalf Of Lee, Dennis K (US 332G) via SLS-RFM
Sent: 03 May 2023 13:15
To: sls-rfm at mailman.ccsds.org
Subject: [Sls-rfm] RFM inputs (batch #3)


SLS-RFM_23-05 and SLS-RFM_23-06 attached.

This message is intended only for the recipient(s) named above. It may contain proprietary information and/or protected content. Any unauthorised disclosure, use, retention or dissemination is prohibited. If you have received this e-mail in error, please notify the sender immediately. ESA applies appropriate organisational measures to protect personal data, in case of data privacy queries, please contact the ESA Data Protection Officer (dpo at esa.int).
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ccsds.org/pipermail/sls-rfm/attachments/20230511/894795f0/attachment.htm>