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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US">In view of our discussion yesterday, it seems we might have to modify the SDLS GB to recommend Frame CRC in all cases to guarantee that all transmission
errors are detected. Your thoughts ?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Gilles MOURY</span><span lang="EN-US" style="font-family:"Times New Roman",serif;color:#1F497D">
<br>
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">CNES Toulouse</span><span lang="EN-US" style="font-family:"Times New Roman",serif;color:#1F497D">
</span><span lang="EN-US" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt">De :</span></b><span style="font-size:11.0pt"> Kazz, Greg (US 312B) <greg.j.kazz@jpl.nasa.gov>
<br>
<b>Envoyé :</b> mercredi 19 octobre 2022 18:03<br>
<b>À :</b> Andres, Brent (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <brent.r.andres@nasa.gov>; Matt Cosby <matt.cosby@goonhilly.org>; Sank, Victor J. (GSFC-567.0)[SCIENCE SYSTEMS AND APPLICATIONS INC] <victor.j.sank@nasa.gov><br>
<b>Cc :</b> Ignacio.Aguilar.Sanchez@esa.int; Moury Gilles <Gilles.Moury@cnes.fr><br>
<b>Objet :</b> No mandatory need for CRC-16 due to addition of SDLS in TC or USLP SDLPs<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">All,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Just cutting and pasting the relevant conclusion from CCSDS 350.5-G (SDLS Green Book) below:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-bottom:15.0pt"><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">As an example, ESA has adopted the SEC mode and the mandatory presence of CRC in its</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">TC Standard (reference [25]).
<span style="background:yellow;mso-highlight:yellow">With BER<10</span></span><span lang="EN-US" style="font-size:10.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">-4
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">, the achievable undetected frame error rate is</span><span lang="EN-US" style="font-size:11.0pt;background:yellow;mso-highlight:yellow"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">below 10
</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">-15
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">. This is 6 orders of magnitude better than the requirement.</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">D5 TELECOMMAND CONCLUSION</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">A modification of the performance requirement for undetected error (10</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Times New Roman",serif">-9
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">) does not appear to</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">be required.</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">As long as the BER conditions to fulfill this performance are met for the particular missions</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">(i.e., BER<10</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Times New Roman",serif">-5
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">), undetected error is expected to be present typically once in 10 years of</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">operation.</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">Given this frequency of undetected error, it does not seem worthwhile to impose a mandatory</span><span lang="EN-US" style="font-size:11.0pt;background:yellow;mso-highlight:yellow"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif;background:yellow;mso-highlight:yellow">CRC for frames, when security is applied</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">, in
order to reduce even more the likelihood that an</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">undetected error is only detected by security (MAC). This conclusion is also valid for the</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">newly introduced short LDPC codes in reference [29], which demonstrate even lower</span><span lang="EN-US" style="font-size:11.0pt"><br>
</span><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">undetected error rates than TC BCH code.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:15.0pt;font-family:"Times New Roman",serif">Greg</span><span lang="EN-US" style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Greg Kazz<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Principal Engineer<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Technical Group Supervisor,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">312B Project Protection, Project Software, and End to End Information System Engineering<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Jet Propulsion Laboratory<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">4800 Oak Grove Dr., M/S 301-490<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">Pasadena, CA 91109</span><span lang="EN-US" style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">1+(818)393 6529(voice)</span><span lang="EN-US" style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">1</span><span lang="ES-MX" style="font-size:11.0pt">+(818)393 6871(fax)</span><span lang="EN-US" style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES-MX" style="font-size:11.0pt">email: <a href="mailto:greg.j.kazz@jpl.nasa.gov">
greg.j.kazz@jpl.nasa.gov</a> </span><span lang="EN-US" style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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