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