<div dir="ltr">Thanks for the clarification. Though now I'm confused about how all the channels would be used simultaneously with an AP only solution (which is my understanding of the kickstarter campaign.) <div><br></div><div>Bob</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jun 23, 2016 at 7:14 PM, David Lang <span dir="ltr"><<a href="mailto:david@lang.hm" target="_blank">david@lang.hm</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I think he is meaning when one unit is talking to one AP the signal levels across multiple channels will be similar. Which is probably fairly true.<div class="HOEnZb"><div class="h5"><br>
<br>
David Lang<br>
<br>
On Thu, 23 Jun 2016, Bob McMahon wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Curious, where does the "in a LAN setup, the variability in [receive]<br>
signal strength is likely small enough" assertion come? Any specific<br>
power numbers here? We test with many combinations of "signal strength<br>
variability" (e.g. deltas range from 0 dBm - 50 dBm) and per different<br>
channel conditions. This includes power variability within the spatial<br>
streams' MiMO transmission. It would be helpful to have some physics<br>
combined with engineering to produce some pragmatic limits to this.<br>
<br>
Also, mobile devices have a goal of reducing power in order to be efficient<br>
with their battery (vs a goal to balance power such that an AP can<br>
receive simultaneously.) Power per bit usually trumps most other design<br>
goals. There market for battery powered wi-fi devices drives a<br>
semi-conductor mfg's revenue so my information come with that bias.<br>
<br>
Bob<br>
<br>
On Thu, Jun 23, 2016 at 1:48 PM, <<a href="mailto:dpreed@reed.com" target="_blank">dpreed@reed.com</a>> wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
The actual issues of transmitting on multiple channels at the same time<br>
are quite minor if you do the work in the digital domain (pre-DAC). You<br>
just need a higher sampling rate in the DAC and add the two signals<br>
together (and use a wideband filter that covers all the channels). No RF<br>
problem.<br>
<br>
Receiving multiple transmissions in different channels is pretty much the<br>
same problem - just digitize (ADC) a wider bandwidth and separate in the<br>
digital domain. the only real issue on receive is equalization - if you<br>
receive two different signals at different receive signal strengths, the<br>
lower strength signal won't get as much dynamic range in its samples.<br>
<br>
But in a LAN setup, the variability in signal strength is likely small<br>
enough that you can cover that with more ADC bits (or have the MAC protocol<br>
manage the station transmit power so that signals received at the AP are<br>
nearly the same power.<br>
<br>
Equalization at transmit works very well when there is a central AP (as in<br>
cellular or normal WiFi systems).<br>
<br>
<br>
<br>
On Thursday, June 23, 2016 4:28pm, "Bob McMahon" <<a href="mailto:bob.mcmahon@broadcom.com" target="_blank">bob.mcmahon@broadcom.com</a>><br>
said:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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An AP per room/area, reducing the tx power (beacon range) has been my<br>
approach and has scaled very well. It does require some wires to each<br>
</blockquote>
AP<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
but I find that paying an electrician to run some quality wiring to<br>
</blockquote>
things<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
that are to remain stationary has been well worth the cost.<br>
<br>
just my $0.02,<br>
Bob<br>
<br>
On Thu, Jun 23, 2016 at 1:10 PM, David Lang <<a href="mailto:david@lang.hm" target="_blank">david@lang.hm</a>> wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Well, just using the 5GHz DFS channels in 80MHz or 160 MHz wide chunks<br>
would be a huge improvement, not many people are using them (yet), and<br>
</blockquote></blockquote>
the<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
wide channels let you get a lot of data out at once. If everything is<br>
within a good range of the AP, this would work pretty well. If you end<br>
</blockquote></blockquote>
up<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
needing multiple APs, or you have many stations, I expect that you will<br>
</blockquote></blockquote>
be<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
better off with more APs at lower power, each using different channels.<br>
<br>
David Lang<br>
<br>
<br>
<br>
<br>
On Thu, 23 Jun 2016, Bob McMahon wrote:<br>
<br>
Date: Thu, 23 Jun 2016 12:55:19 -0700<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
From: Bob McMahon <<a href="mailto:bob.mcmahon@broadcom.com" target="_blank">bob.mcmahon@broadcom.com</a>><br>
To: Dave Taht <<a href="mailto:dave.taht@gmail.com" target="_blank">dave.taht@gmail.com</a>><br>
Cc: <a href="mailto:make-wifi-fast@lists.bufferbloat.net" target="_blank">make-wifi-fast@lists.bufferbloat.net</a>,<br>
"<a href="mailto:cerowrt-devel@lists.bufferbloat.net" target="_blank">cerowrt-devel@lists.bufferbloat.net</a>"<br>
<<a href="mailto:cerowrt-devel@lists.bufferbloat.net" target="_blank">cerowrt-devel@lists.bufferbloat.net</a>><br>
Subject: Re: [Make-wifi-fast] more well funded attempts showing market<br>
demand<br>
for better wifi<br>
<br>
<br>
hmm, I'm skeptical. To use multiple carriers simultaneously is<br>
</blockquote></blockquote></blockquote>
difficult<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
per RF issues. Even if that is somehow resolved, to increase<br>
</blockquote></blockquote></blockquote>
throughput<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
usually requires some form of channel bonding, i.e. needed on both<br>
</blockquote></blockquote></blockquote>
sides,<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
and brings in issues with preserving frame ordering. If this is just<br>
channel hopping, that needs coordination between both sides (and isn't<br>
simultaneous, possibly costing more than any potential gain.) An AP<br>
</blockquote></blockquote></blockquote>
only<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
solution can use channel switch announcements (CSA) but there is a<br>
</blockquote></blockquote></blockquote>
cost to<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
those as well.<br>
<br>
I guess don't see any break though here and the marketing on the site<br>
seems<br>
to indicate something beyond physics, at least the physics that I<br>
understand. Always willing to learn and be corrected if I'm<br>
misunderstanding things.<br>
<br>
Bob<br>
<br>
On Wed, Jun 22, 2016 at 10:18 AM, Dave Taht <<a href="mailto:dave.taht@gmail.com" target="_blank">dave.taht@gmail.com</a>><br>
</blockquote></blockquote></blockquote>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
On Wed, Jun 22, 2016 at 10:03 AM, Dave Taht <<a href="mailto:dave.taht@gmail.com" target="_blank">dave.taht@gmail.com</a>><br>
</blockquote></blockquote></blockquote>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<br>
</blockquote>
<br>
</blockquote></blockquote></blockquote></blockquote>
<a href="https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi?ref=backerkit" rel="noreferrer" target="_blank">https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi?ref=backerkit</a><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
"Portal is the first and only router specifically engineered to cut<br>
through and avoid congestion, delivering consistent, high-performance<br>
WiFi with greater coverage throughout your home.<br>
<br>
Its proprietary spectrum turbocharger technology provides access to<br>
300% more of the radio airwaves than any other router, improving<br>
performance by as much as 300x, and range and coverage by as much as<br>
2x in crowded settings, such as city homes and multi-unit apartments"<br>
<br>
It sounds like they are promising working DFS support.<br>
<br>
</blockquote>
<br>
It's not clear what chipset they are using (they are claiming wave2) -<br>
but they are at least publicly claiming to be using openwrt. So I<br>
threw in enough to order one for september, just so I could comment on<br>
their kickstarter page. :)<br>
<br>
I'd have loved to have got in earlier (early shipments are this month<br>
apparently), but those were sold out.<br>
<br>
<br>
<br>
<br>
</blockquote></blockquote></blockquote></blockquote>
<a href="https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi/comments" rel="noreferrer" target="_blank">https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi/comments</a><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
--<br>
Dave Täht<br>
Let's go make home routers and wifi faster! With better software!<br>
<a href="http://blog.cerowrt.org" rel="noreferrer" target="_blank">http://blog.cerowrt.org</a><br>
<br>
</blockquote>
<br>
<br>
<br>
--<br>
Dave Täht<br>
Let's go make home routers and wifi faster! With better software!<br>
<a href="http://blog.cerowrt.org" rel="noreferrer" target="_blank">http://blog.cerowrt.org</a><br>
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<br>
<br>
</blockquote></blockquote>
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<br>
<br>
</blockquote>
<br>
</blockquote>
<br>
<br>
<br>
</blockquote>
</blockquote>
</div></div></blockquote></div><br></div>