From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x234.google.com (mail-wm0-x234.google.com [IPv6:2a00:1450:400c:c09::234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A30863BA8E for ; Fri, 3 Nov 2017 19:33:37 -0400 (EDT) Received: by mail-wm0-x234.google.com with SMTP id r196so4258942wmf.2 for ; Fri, 03 Nov 2017 16:33:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=2Ok51St3Ip7fqTsOOLR0qtz98/s0CWQ57OeuqZvzR10=; b=e2W/PIRFgTNcDM7219iWup6uU0QSNeGg2nEAzNF0Vodope3dFgmVjcdoHVz8vm8oQh hoFBqk2byDnphBYnhi8Ycp296JZ0pLlORVD33rH19UFcMsJLAJ73Qvphaxk3EsQwiZ23 B7B8Id5iGz3WQJao9BPG584zxfvC15U/Vbt8g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=2Ok51St3Ip7fqTsOOLR0qtz98/s0CWQ57OeuqZvzR10=; b=HjU0y6fcPDN/hJrj2u7o6hGVryN+2p9eC1BA7bvePoUl0pV2aApMu+rKFeGmSDCEOg bIdfMfpwQudIrQx7saMnJtfOqVvtEShDo37s3MfeCVC3uW67UoWz26DIYYLtabjKIA/b a8b6KDllo8QPGqGO+hrLlMkfT3pFEhxQLfgkloTvLeQrJlguWa9Bxs0EjjpnhpYA9QR3 tZRKyrXxCrHxyvMqgQrgF3KN9Ct7A4F0KRFTmZBZ0qAYbgQR3IAVIl6H0WHBG3LcKSv6 KEW1HSoMv5/fWFtUPop0Ios/lCE6A1G4jAx54cECtJ4kj01kdazJ91uWXy+17V/Ftk2n 6qnA== X-Gm-Message-State: AJaThX5ypWYN6yucbkFae7sWPSp3S2ZVh6zzhAa3ZbQCN9p0zQ7Aqas/ NwF5pJ/E5QWXUq8nxew5guyv8wUzjQBlBN5Trejpxw== X-Google-Smtp-Source: ABhQp+Q9uzP342VyUc92HNK/BtrPA322D+3/349UUL9yVRdhyVIwikG6iwD2yXUztS6Qgn1ki0E79btHZr78fZ7ZpRs= X-Received: by 10.80.190.202 with SMTP id e10mr2053356edk.243.1509752016526; Fri, 03 Nov 2017 16:33:36 -0700 (PDT) MIME-Version: 1.0 Received: by 10.80.186.35 with HTTP; Fri, 3 Nov 2017 16:33:35 -0700 (PDT) In-Reply-To: References: <87tvybm0x2.fsf@toke.dk> From: Bob McMahon Date: Fri, 3 Nov 2017 16:33:35 -0700 Message-ID: To: Aaron Wood Cc: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , make-wifi-fast@lists.bufferbloat.net Content-Type: multipart/alternative; boundary="089e08249e10a50c8d055d1c8862" Subject: Re: [Make-wifi-fast] Wiring up a wireless testbed X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 Nov 2017 23:33:37 -0000 --089e08249e10a50c8d055d1c8862 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable A way I think about is to emulate the "system" in both range/power (attenuation) and in mixing (phase shifts) It's a diagonal matrix for range feeding into an h-matrix for the mixing. A butler matrix can be used for the latter if variable phase control isn't required, e.g. you don't care about spatial stream relative powers. On adding energy for "random" noise, some knobs of concern are the energy detect on the tx and signal floor for the rx. These sources can be fed into the same h-matrix through their own d-matrices. This won't replace field tests but helps get closer towards that while providing for repeat ability. Also, equally important by my judgment, though not related to wireless, is to synchronize the clocks on the PCs. An oven controlled oscillator and PTP works well towards that goal. Bob On Fri, Nov 3, 2017 at 4:03 PM, Aaron Wood wrote: > What this setup also removes is random noise, which is good for > repeatability, but bad for real-life testing. My experiences doing simila= r > are that there isn=E2=80=99t much of a grey area between a =E2=80=9Cgreat= =E2=80=9D > throughput/packet error rate and =E2=80=9Cnothing works=E2=80=9D. > > It also removes the real-world crosstalk between the antennas. > > So good for some things, especially automated tests, but it=E2=80=99s not= a > replacement for real field tests in the presence of random noise. > > On Fri, Nov 3, 2017 at 15:51 Toke H=C3=B8iland-J=C3=B8rgensen wrote: > >> Since I had to (physically) move my wireless testbed recently, I had to >> figure out a way to run reliable WiFi experiments in a cramped server >> room. I ended up wiring everything up instead of running over the air, >> and documented the process here, in case anyone wants to replicate it: >> >> https://blog.tohojo.dk/2017/11/building-a-wireless- >> testbed-with-wires.html >> >> Also, if anyone sees any fatal flaw in that setup, please do let me know >> :) >> >> -Toke >> _______________________________________________ >> Make-wifi-fast mailing list >> Make-wifi-fast@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/make-wifi-fast > > > _______________________________________________ > Make-wifi-fast mailing list > Make-wifi-fast@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/make-wifi-fast > --089e08249e10a50c8d055d1c8862 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
A way I think about is to emulate the "system" i= n both range/power (attenuation) and in mixing (phase shifts) =C2=A0 It'= ;s a diagonal matrix for range feeding into an h-matrix for the mixing.=C2= =A0 A butler matrix can be used for the latter if variable phase control is= n't required, e.g. you don't care about spatial stream relative pow= ers.

On adding energy for "random" noise, some knobs of co= ncern are the energy detect on the tx and signal floor for the rx. =C2=A0 T= hese sources can be fed into the same h-matrix through their own d-matrices= .=C2=A0 This won't replace field tests but helps get closer towards tha= t while providing for repeat ability.

Also, equally important by my = judgment, though not related to wireless, is to synchronize the clocks on t= he PCs.=C2=A0 An oven controlled oscillator and PTP works well towards that= goal.
=C2=A0
Bob



On Fri, Nov 3, 2017 at 4:03 PM, Aaron Wood <woody7= 7@gmail.com> wrote:
What th= is setup also removes is random noise, which is good for repeatability, but= bad for real-life testing. My experiences doing similar are that there is= n=E2=80=99t much of a grey area between a =E2=80=9Cgreat=E2=80=9D throughpu= t/packet error rate and =E2=80=9Cnothing works=E2=80=9D.

It also rem= oves the real-world crosstalk between the antennas.

So good for some= things, especially automated tests, but it=E2=80=99s not a replacement for= real field tests in the presence of random noise.

On Fri, Nov = 3, 2017 at 15:51 Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk> wrote:
Since I had to (physically) move my wireless testbed = recently, I had to
figure out a way to run reliable WiFi experiments in a cramped server
room. I ended up wiring everything up instead of running over the air,
and documented the process here, in case anyone wants to replicate it:

https://blog.tohojo.dk/201= 7/11/building-a-wireless-testbed-with-wires.html

Also, if anyone sees any fatal flaw in that setup, please do let me know :)=

-Toke
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Make-wifi-fast mailing list
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https://lists.bufferbloat.net/listinfo/mak= e-wifi-fast

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Make-wifi-fast mailing list
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