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    <p>Nicolò, and all,<br>
    </p>
    <p>We agree that we all can run simulations using the model
      described on either p. 2 or p. 7 of the updated presentation
      Geraldine sent out, and scale from either model to the other
      afterwards.</p>
    <p>We also agree that our top priorities do not include computing
      the mutual information at this time, although it is an interesting
      idea.<br>
    </p>
    <p>Our top priority will be simulating the codes according to the p.
      2/p. 7 model, in a non-fading environment.</p>
    <p>Let's plan to discuss the channel interleaver next Tuesday.  To
      simplify things, I suggest that we consider just one (N,B)
      interleaver for each fading case we want to consider, instead of
      three.  We just need to make it sufficiently long to overcome the
      fade -- e.g., we could pick it to be some multiple of the
      coherence time of the fade.  (I don't think we learn much from
      also simulating an insufficiently long interleaver, since all
      codes will fail with it; and likewise, the performance of a
      longer-than-necessary interleaver will not perform substantially
      different than the sufficiently long interleaver.)  If we had to
      pick just one fading case, case A might not be the best one, since
      that is a mild case.  A, D, E, and H show progressively more
      difficulty.<br>
    </p>
    <p>     ----Jon<br>
    </p>
    <div class="moz-signature"><strong>Jon Hamkins</strong><br>
      Lead Technologist<br>
      33   |   Communications, Tracking, and Radar Division<br>
      <strong>O</strong> 818-354-4764   |   <strong>M</strong>
      626-658-6220 <br>
      <br>
      <strong>JPL</strong>   |   jpl.nasa.gov
    </div>
    <div class="moz-cite-prefix">On 4/28/2020 8:33 AM, Nicolo Mazzali
      (external) wrote:<br>
    </div>
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cite="mid:32623_1588087987_5EA84CAF_32623_1_3_OFFBDC9911.26238008-ONC1258558.0051F2A9-C1258558.00556BF1@esa.int">
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      <span style=" font-size:10pt;font-family:sans-serif">Dear All, </span>
      <br>
      <br>
      <span style=" font-size:10pt;font-family:sans-serif">Thanks a lot
        to
        Dirk and Géraldine for the very useful contribution.</span>
      <br>
      <span style=" font-size:10pt;font-family:sans-serif">In the past
        we
        used the "ampère model" (in slide 7 from Géraldine), and, as
        Géraldine correctly pointed out, it's just a matter of scaling
        to move
        from that to the "photons per bit model" (slide 8). So for ESA
        it's fine either way.</span>
      <br>
      <br>
      <span style=" font-size:10pt;font-family:sans-serif">I think that
        the
        last details that we need to agree upon before running the new
        simulation
        campaign concern the fading and the interleaver dimensioning. In
        our opinion
        it is important to include them both in the assessment, since in
        past meetings
        it was shown that there is an intertwined relationship between
        the code,
        the channel, and the interleaver. </span>
      <br>
      <span style=" font-size:10pt;font-family:sans-serif">For
        simplicity
        we propose to use fading A from the DLR, leaving the performance
        assessment
        with the other time series for the green book. On the
        interleaver dimensioning,
        since it depends both on the symbol rate and the fading, I think
        that we
        should pick 3 different (N,B) values. Honestly, I don't think we
        have the
        time (nor the need) for an accurate optimization of these
        parameters, so
        we might well live with a rule-of-thumb dimensioning.</span>
      <br>
      <br>
      <span style=" font-size:10pt;font-family:sans-serif">Finally,
        concerning
        Géraldine's request for the mutual information, we still don't
        think that
        such investigation would be worth the required effort. This
        applies in
        particular to fading channels, where the computation of the
        mutual information
        is not as straightforward as on the AWGN channel, especially
        when the fading
        is not generated according to a given statistical model but
        numerically
        by means of a time series. Also, including the interleaver would
        further
        complicate the analysis. On top of this, we are not using Matlab
        for our
        simulations, and including the mutual information in our
        simulator would
        inevitably delay the delivery of the results of the new
        simulation campaign.</span>
      <br>
      <span style=" font-size:10pt;font-family:sans-serif"><br>
        Kind regards,</span>
      <br>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:8pt;color:#808080;font-family:Verdana"><b>Modis
            for ESA - European Space Agency</b></span><span style="
          font-size:12pt;font-family:Tms Rmn">
        </span><span style="
          font-size:8pt;color:#00a1e0;font-family:Verdana"><br>
          <br>
          Nicolò Mazzali, PhD </span><span style="
          font-size:8pt;color:#808080;font-family:Verdana"><br>
          Communication Systems & Technologies Engineer</span><span
          style=" font-size:12pt;font-family:Tms Rmn">
        </span><span style="
          font-size:8pt;color:#808080;font-family:Verdana"><br>
          <br>
          Telecommunications Section (TEC-ESC)</span><span style="
          font-size:12pt;font-family:Tms Rmn">
        </span><span style="
          font-size:8pt;color:#808080;font-family:Verdana"><br>
          Radio Frequency Systems Division (TEC-ES)</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:8pt;color:#808080;font-family:Verdana">Directorate
          of Technology, Engineering & Quality (D/TEC)<b><br>
            <br>
            <br>
            ESTEC</b><br>
          Keplerlaan 1, PO Box 299<br>
          NL-2200 AG Noordwijk, The Netherlands</span><span style="
          font-size:8pt;color:#0082bf;font-family:Verdana"><u><br>
          </u></span><a href="mailto:nicolo.mazzali@esa.int"
          moz-do-not-send="true"><span style="
            font-size:8pt;color:#0082bf;font-family:Verdana"><u>nicolo.mazzali@esa.int</u></span></a><span
          style=" font-size:8pt;color:#808080;font-family:Verdana">
          | </span><a href="http://www.esa.int/" moz-do-not-send="true"><span
            style=" font-size:8pt;color:#8f8f8f;font-family:Verdana"><u>www.esa.int</u></span></a><span
          style=" font-size:8pt;color:#808080;font-family:Verdana"><br>
          T +31 71 56 53215</span></p>
      <br>
      <br>
      <br>
      <br>
      <span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">From:
               </span><span style="
        font-size:9pt;font-family:sans-serif"><a class="moz-txt-link-rfc2396E" href="mailto:Dirk.Giggenbach@dlr.de"><Dirk.Giggenbach@dlr.de></a></span>
      <br>
      <span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">To:
               </span><span style="
        font-size:9pt;font-family:sans-serif"><a class="moz-txt-link-rfc2396E" href="mailto:Jon.Hamkins@jpl.caltech.edu"><Jon.Hamkins@jpl.caltech.edu></a></span>
      <br>
      <span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Cc:
               </span><span style="
        font-size:9pt;font-family:sans-serif"><a class="moz-txt-link-abbreviated" href="mailto:SLS-OPT@mailman.ccsds.org">SLS-OPT@mailman.ccsds.org</a></span>
      <br>
      <span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Date:
               </span><span style="
        font-size:9pt;font-family:sans-serif">23/04/2020
        20:04</span>
      <br>
      <span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Subject:
               </span><span style="
        font-size:9pt;font-family:sans-serif">Re:
        [SLS-OPT] O3K channel model</span>
      <br>
      <span style=" font-size:9pt;color:#5f5f5f;font-family:sans-serif">Sent
        by:        </span><span style="
        font-size:9pt;font-family:sans-serif">"SLS-OPT"
        <a class="moz-txt-link-rfc2396E" href="mailto:sls-opt-bounces@mailman.ccsds.org"><sls-opt-bounces@mailman.ccsds.org></a></span>
      <br>
      <hr noshade="noshade">
      <br>
      <br>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">Hi
          Jon,</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri"> </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">we
          do not have data APD-RFEs for that low rate which we could
          test/measure.</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">I
          checked some datasheets, the one coming closest to 1.22Mbps is
          the LaserComponents
          IAG350H1D –APD Receiver with 1MHz Bandwidth and 350µm APD.
           They
          don’t show dark current in the DS.</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri"><br>
          These values seem close to best compared to other receivers:</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">Responsivity=94MV/W
           ,  I guess that includes Amplification of M=10, so TIA would
          be ~9MOhm </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">NEP=32fW/sqrt(Hz)
            -   referred noise density of 0.3E-12 A/sqrt(Hz)  or
           3µV/sqrt(Hz)
           </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><a
          href="https://www.lasercomponents.com/de-en/product/apd-receivers/"
          moz-do-not-send="true"><span style="
            font-size:11pt;color:blue;font-family:Calibri"><u>https://www.lasercomponents.com/de-en/product/apd-receivers/</u></span></a><span
          style=" font-size:11pt;color:#004080;font-family:Calibri">
        </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri"> </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">Hope
          that helps,</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri"> </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri">Dirk</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri"> </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:11pt;color:#004080;font-family:Calibri"> </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:12pt;font-family:Times New Roman"> </span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:10pt;font-family:Tahoma"><b>Von:</b>
          SLS-OPT [</span><a
          href="mailto:sls-opt-bounces@mailman.ccsds.org"
          moz-do-not-send="true"><span style="
            font-size:10pt;font-family:Tahoma">mailto:sls-opt-bounces@mailman.ccsds.org</span></a><span
          style=" font-size:10pt;font-family:Tahoma">]
          <b>Im Auftrag von </b>Jon Hamkins via SLS-OPT<b><br>
            Gesendet:</b> Mittwoch, 15. April 2020 17:20<b><br>
            An:</b> <a class="moz-txt-link-abbreviated" href="mailto:SLS-OPT@mailman.ccsds.org">SLS-OPT@mailman.ccsds.org</a><b><br>
            Betreff:</b> [SLS-OPT] O3K channel model</span></p>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:12pt;font-family:Times New Roman"> </span></p>
      <br>
      <span style=" font-size:12pt;font-family:Times New Roman">Attached
        is the O3K channel model we discussed yesterday.  It also
        contains
        a suggestion for how to state the O3K coding performance.  I
        welcome
        your comments.  If we can agree to the model in the next week or
        so,
        each agency may be able to begin simulating with it and discuss
        some initial
        results at the May teleconferences.</span>
      <br>
      <span style=" font-size:12pt;font-family:Times New Roman">A few
        notes:</span>
      <ul>
        <li><span style=" font-size:12pt;font-family:Times New Roman">I
            am suggesting
            we study 10 Gsps, 78.125 Msps, and 1.22 Mbps, since those
            include the highest
            and lowest data rates and one in the middle.</span>
        </li>
        <li><span style=" font-size:12pt;font-family:Times New Roman">I
            don't have
            a good suggestion for the TIA noise density at 1.22 Msps.
             Dirk, would
            you be able to supply a number?</span>
        </li>
        <li><span style=" font-size:12pt;font-family:Times New Roman">I
            have algebraically
            simplified the expressions for the means and variances.  You
            can compare
            the model to the expressions Dariush presented on yesterday
            (p. 5), and
            check my algebra.</span>
        </li>
        <li><span style=" font-size:12pt;font-family:Times New Roman">I
            have included
            the fading parameter as well.  Just set rho=1 if you want no
            fading.</span></li>
      </ul>
      <span style=" font-size:12pt;font-family:Times New Roman"> 
           ----Jon</span>
      <p style="margin-top:0px;margin-Bottom:0px"><span style="
          font-size:12pt;font-family:Times New Roman">--
          <b><br>
            Jon Hamkins</b><br>
          Lead Technologist<br>
          33   |   Communications, Tracking, and Radar Division<b><br>
            O</b> 818-354-4764   |   <b>M</b> 626-658-6220 <br>
          <b><br>
            JPL</b>   |   jpl.nasa.gov </span></p>
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