<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<div class="moz-cite-prefix">On 5/03/2022 7:38 pm, Dick Roy wrote:<br>
</div>
<blockquote type="cite" cite="mid:2DA12D3D736443699EBFD93FDC9325A2@SRA6">
<meta name="Generator" content="Microsoft Word 11 (filtered
medium)">
<o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PlaceType">
<o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PlaceName">
<o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="State">
<o:smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place">
<!--[if !mso]>
<style>
st1\:*{behavior:url(#default#ieooui) }
</style>
<![endif]-->
<style>@font-face
{font-family:"MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}@font-face
{font-family:"\@MS Mincho";
panose-1:0 0 0 0 0 0 0 0 0 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}div.Section1
{page:Section1;}</style>
<div class="Section1">
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt"><o:p> </o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt"><o:p> </o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt">-----Original Message-----<br>
From: Starlink
[<a class="moz-txt-link-freetext" href="mailto:starlink-bounces@lists.bufferbloat.net">mailto:starlink-bounces@lists.bufferbloat.net</a>] On
Behalf Of Ulrich
Speidel<br>
Sent: Friday, March 4, 2022 4:14 PM<br>
To: David Lang<br>
Cc: <a class="moz-txt-link-abbreviated" href="mailto:starlink@lists.bufferbloat.net">starlink@lists.bufferbloat.net</a><br>
Subject: Re: [Starlink] Starlink Digest, Vol 12,
Issue 6</span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt"><o:p> </o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt">True, but Starlink is designed as a high
bandwidth, low latency (OK, we
<o:p></o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt">won't mention their bufferbloat issues
again here), and (currently) low
<o:p></o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt">user density service.<o:p></o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt"><o:p> </o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt">Bandwidth-wise, good old Shannon and
Hartley are agnostic about whether
<o:p></o:p></span></font></p>
<p class="MsoPlainText"><font size="2" face="Courier
New"><span style="font-size:
10.0pt">you divide your channel between 1 or a
million users. <o:p></o:p></span></font></p>
<p class="MsoPlainText"><b><i><font size="2" face="Courier New"><span style="font-size:10.0pt;font-weight:bold;font-style:italic">[RR]
But they are
assuming a “single” channel in the time
domain. When you can
take advantage of other dimensions (eg. space)
to create more channels, (aka SDMA)
the capacity goes up!</span></font></i></b></p>
</div>
</o:smarttagtype></o:smarttagtype></o:smarttagtype></o:smarttagtype></blockquote>
<font size="2"><font face="Courier New"><i><b>Taken as read - but
it's beside the point. Shannon-Hartley allows you to do what
was proposed - turning a channel that supplies a small
number of users with a lot of capacity each into one that
supplies a large number of users with a little capacity
each, and of course if you add diversity (space,
polarisation, ...) then this applies even more so. But the
point is that each communication system is designed around
an expectation of how many users will access it, and that
you can't simply take an existing technology and somehow
assume that it will work with a larger number of users just
because it's theoretically possible. Basically, you can't
simply throw more dishys at the problem if you need to serve
more users.</b></i></font></font><br>
<br>
<pre class="moz-signature" cols="72">--
****************************************************************
Dr. Ulrich Speidel
School of Computer Science
Room 303S.594 (City Campus)
The University of Auckland
<a class="moz-txt-link-abbreviated" href="mailto:u.speidel@auckland.ac.nz">u.speidel@auckland.ac.nz</a>
<a class="moz-txt-link-freetext" href="http://www.cs.auckland.ac.nz/~ulrich/">http://www.cs.auckland.ac.nz/~ulrich/</a>
****************************************************************
</pre>
</body>
</html>