<div dir="ltr">We have hundreds of test rigs in multiple labs all over geography. Each rig is shielded from the others using things like RF enclosures. We want reproducibility in the RF paths/channels as well as variability. Most have built fixed rigs using conducted equipment. This is far from anything real. A butler matrix produces great condition numbers but that makes it too easy for MIMO rate selection algorithms.<br><br>Our real world test is using a real house that has been rented. Not cheap nor scalable.<br><br>There is quite a gap between the two. A RF path device that supports both variable range and variable mixing is a step towards closing the gap.<br><br>Bob</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Aug 7, 2021 at 10:07 PM Dick Roy <<a href="mailto:dickroy@alum.mit.edu">dickroy@alum.mit.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div lang="EN-US">
<div class="gmail-m_2644358729133911847Section1">
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:10pt;font-family:Arial;color:navy"><u></u> <u></u></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:10pt;font-family:Arial;color:navy"><u></u> <u></u></span></font></p>
<div>
<div class="MsoNormal" align="center" style="text-align:center"><font size="3" face="Times New Roman"><span style="font-size:12pt">
<hr size="3" width="100%" align="center">
</span></font></div>
<p class="MsoNormal"><b><font size="2" face="Tahoma"><span style="font-size:10pt;font-family:Tahoma;font-weight:bold">From:</span></font></b><font size="2" face="Tahoma"><span style="font-size:10pt;font-family:Tahoma"> Starlink
[mailto:<a href="mailto:starlink-bounces@lists.bufferbloat.net" target="_blank">starlink-bounces@lists.bufferbloat.net</a>] <b><span style="font-weight:bold">On Behalf Of </span></b>Bob McMahon<br>
<b><span style="font-weight:bold">Sent:</span></b> Monday, August 2, 2021 6:24
PM<br>
<b><span style="font-weight:bold">To:</span></b> Leonard Kleinrock<br>
<b><span style="font-weight:bold">Cc:</span></b> <a href="mailto:starlink@lists.bufferbloat.net" target="_blank">starlink@lists.bufferbloat.net</a>;
Make-Wifi-fast; Cake List; <a href="mailto:codel@lists.bufferbloat.net" target="_blank">codel@lists.bufferbloat.net</a>; cerowrt-devel; bloat<br>
<b><span style="font-weight:bold">Subject:</span></b> Re: [Starlink] [Cake]
[Make-wifi-fast] [Cerowrt-devel] Due Aug 2: Internet Quality workshop CFP for
the internet architecture board</span></font><u></u><u></u></p>
</div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12pt"><u></u> <u></u></span></font></p>
<div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12pt">I found the following talk relevant to distances between all the
nodes. <a href="https://www.youtube.com/watch?v=PNoUcQTCxiM" target="_blank">https://www.youtube.com/watch?v=PNoUcQTCxiM</a>
<br>
<br>
Distance is an abstract idea but applies to energy into a node as well as
phylogenetic trees. It's the same problem, i.e. fitting a distance matrix using
some sort of tree. I've found the five branch tree works well for four nodes.<font color="navy"><span style="color:navy"><u></u><u></u></span></font></span></font></p>
<p class="MsoNormal"><b><i><font size="2" color="navy" face="Arial"><span style="font-size:10pt;font-family:Arial;color:navy;font-weight:bold;font-style:italic">[RR] These trees are means for approximating a higher
dimensional real-world problem with a lower dimensional structure. You may be
doing this to save hardware when trying to cable up some complex test scenarios,
however I’m wondering why? Why not just put the STAs in the lab and turn them
on rather than cabling them?<u></u><u></u></span></font></i></b></p>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12pt"><br>
<br>
Bob <u></u><u></u></span></font></p>
</div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12pt"><u></u> <u></u></span></font></p>
<div>
<div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12pt">On Mon, Aug 2, 2021 at 5:37 PM Leonard Kleinrock <<a href="mailto:lk@cs.ucla.edu" target="_blank">lk@cs.ucla.edu</a>> wrote:<u></u><u></u></span></font></p>
</div>
<blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0in 0in 0in 6pt;margin-left:4.8pt;margin-right:0in">
<p class="MsoNormal" style="margin-bottom:12pt"><font size="3" face="Times New Roman"><span style="font-size:12pt">These cases are what my
student, Fouad Tobagi and I called the Hidden Terminal Problem (with the Busy
Tone solution) back in 1975.<br>
<br>
Len <br>
<br>
<br>
> On Aug 2, 2021, at 4:16 PM, David Lang <<a href="mailto:david@lang.hm" target="_blank">david@lang.hm</a>> wrote:<br>
> <br>
> If you are going to setup a test environment for wifi, you need to include
the ability to make a fe cases that only happen with RF, not with wired
networks and are commonly overlooked<br>
> <br>
> 1. station A can hear station B and C but they cannot hear each other<br>
> 2. station A can hear station B but station B cannot hear station A 3.
station A can hear that station B is transmitting, but not with a strong enough
signal to decode the signal (yes in theory you can work around interference,
but in practice interference is still a real thing)<br>
> <br>
> David Lang<br>
> <u></u><u></u></span></font></p>
</blockquote>
</div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12pt"><br>
</span></font><font size="2"><span style="font-size:10pt;background:white">This
electronic communication and the information and any files transmitted with it,
or attached to it, are confidential and are intended solely for the use of the
individual or entity to whom it is addressed and may contain information that
is confidential, legally privileged, protected by privacy laws, or otherwise
restricted from disclosure to anyone else. If you are not the intended
recipient or the person responsible for delivering the e-mail to the intended
recipient, you are hereby notified that any use, copying, distributing,
dissemination, forwarding, printing, or copying of this e-mail is strictly
prohibited. If you received this e-mail in error, please return the e-mail to
the sender, delete it from your computer, and destroy any printed copy of it.</span></font><u></u><u></u></p>
</div>
</div>
</blockquote></div>
<br>
<span style="background-color:rgb(255,255,255)"><font size="2">This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it.</font></span>