From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x235.google.com (mail-wm0-x235.google.com [IPv6:2a00:1450:400c:c09::235]) (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 0E2FC3B2C6 for ; Thu, 23 Jun 2016 17:41:21 -0400 (EDT) Received: by mail-wm0-x235.google.com with SMTP id a66so1166670wme.0 for ; Thu, 23 Jun 2016 14:41:21 -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=QbV6GuMemSIxAOQ1zGWc2130MrL+IwdLIThhKOeHCO8=; b=Cpua0OA+48DbHWeDf3KshrH2sGqvaUxmOOXm1OOV5EL0iZ4IFLjqGbUwin4/wic6m5 WyrqdAuXJ0qgwsnh06XxlSABLZu3dTexr2EPXYWyJzQpW+E1kyRGrHm5INJ+H/qMLbVW QkOxIbii6GPcElLw2QTn39UnAzR0HvU5+YLjI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=QbV6GuMemSIxAOQ1zGWc2130MrL+IwdLIThhKOeHCO8=; b=Gn5+pTzQggUoEKa4U7xsq732N93M0gKjCBwxTWqbJ6IbEOj1Q7284YvxIR0jaO+E3U b6J6h7J52SOEh+N1gi1oVox0ynxj42t+Vjykb/uLw3cyVBvzfUKQ8kI0IztvxvblEzqd RYZMh1LWOu1L/s/OPnbpGWUeFhUUrrjLbUBOwiOQ0LYjV7Qt/9SAsvZhTpgG4nkvWGYl HXYkbl2qvTXRWYL29hejDMgDwDjtyROcY07/DgJOKho1f6ZRWwoyh4RQi7+01LZO1uyr KQBFyNstpQTE3EWKRpBIoZtirWumqDtJjJ0dc/EI0bomL6zP/eXe0aKyEt5H6Xmt1kU9 21Og== X-Gm-Message-State: ALyK8tK5eHHMpbCnAWffBfnRDhAASFJrBcn8RCxVPdaDCwL5INbRX1iWFWw9TD3CYi18tfEdPyKXYCfRrgP6FRha X-Received: by 10.28.31.140 with SMTP id f134mr14987511wmf.69.1466718080565; Thu, 23 Jun 2016 14:41:20 -0700 (PDT) MIME-Version: 1.0 Received: by 10.194.239.202 with HTTP; Thu, 23 Jun 2016 14:41:19 -0700 (PDT) In-Reply-To: <1466714880.88621749@apps.rackspace.com> References: <1466714880.88621749@apps.rackspace.com> From: Bob McMahon Date: Thu, 23 Jun 2016 14:41:19 -0700 Message-ID: To: dpreed@reed.com Cc: David Lang , make-wifi-fast@lists.bufferbloat.net, "cerowrt-devel@lists.bufferbloat.net" Content-Type: multipart/alternative; boundary=001a114b41062e43070535f8ea6c Subject: Re: [Make-wifi-fast] more well funded attempts showing market demand for better wifi 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: Thu, 23 Jun 2016 21:41:22 -0000 --001a114b41062e43070535f8ea6c Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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, 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 protoc= ol > 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 i= n > cellular or normal WiFi systems). > > > > On Thursday, June 23, 2016 4:28pm, "Bob McMahon" > said: > > > _______________________________________________ > > Make-wifi-fast mailing list > > Make-wifi-fast@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/make-wifi-fast > > 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 > AP > > but I find that paying an electrician to run some quality wiring to > things > > that are to remain stationary has been well worth the cost. > > > > just my $0.02, > > Bob > > > > On Thu, Jun 23, 2016 at 1:10 PM, David Lang 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 > the > >> wide 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 > up > >> needing multiple APs, or you have many stations, I expect that you wil= l > be > >> better 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 > >>> To: Dave Taht > >>> Cc: make-wifi-fast@lists.bufferbloat.net, > >>> "cerowrt-devel@lists.bufferbloat.net" > >>> > >>> Subject: Re: [Make-wifi-fast] more well funded attempts showing marke= t > >>> demand > >>> for better wifi > >>> > >>> > >>> hmm, I'm skeptical. To use multiple carriers simultaneously is > difficult > >>> per RF issues. Even if that is somehow resolved, to increase > throughput > >>> usually requires some form of channel bonding, i.e. needed on both > sides, > >>> and 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 > only > >>> solution can use channel switch announcements (CSA) but there is a > cost to > >>> 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 > wrote: > >>> > >>> On Wed, Jun 22, 2016 at 10:03 AM, Dave Taht > wrote: > >>>> > >>>>> > >>>>> > >>>> > https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi?= ref=3Dbackerkit > >>>> > >>>>> > >>>>> "Portal is the first and only router specifically engineered to cut > >>>>> through and avoid congestion, delivering consistent, high-performan= ce > >>>>> 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 a= s > >>>>> 2x in crowded settings, such as city homes and multi-unit apartment= s" > >>>>> > >>>>> 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 mont= h > >>>> apparently), but those were sold out. > >>>> > >>>> > >>>> > >>>> > https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi/= comments > >>>> > >>>> > >>>> > >>>>> -- > >>>>> Dave T=C3=A4ht > >>>>> Let's go make home routers and wifi faster! With better software! > >>>>> http://blog.cerowrt.org > >>>>> > >>>> > >>>> > >>>> > >>>> -- > >>>> Dave T=C3=A4ht > >>>> Let's go make home routers and wifi faster! With better software! > >>>> http://blog.cerowrt.org > >>>> _______________________________________________ > >>>> 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 > >> > >> > > > > > --001a114b41062e43070535f8ea6c Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Curious, where does the &= quot;in a LAN setup, the variability in [receive] signal strength is likely= small enough" assertion come? =C2=A0 Any specific power numbers here?= We test with many combinations of "signal strength variability" = (e.g. deltas range from 0 dBm - =C2=A050 dBm) and per different channel con= ditions.=C2=A0 This includes power variability within the spatial streams&#= 39; MiMO transmission. =C2=A0 It would be helpful to have some physics comb= ined 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 A= P can receive=C2=A0simultaneously.) =C2=A0Power per bit usually trumps most= other design goals.=C2=A0 There market for battery powered wi-fi devices d= rives a semi-conductor mfg's revenue so my information come with that b= ias.

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).= =C2=A0 You just need a higher sampling rate in the DAC and add the two sign= als together (and use a wideband filter that covers all the channels).=C2= =A0 No RF problem.

Receiving multiple transmissions in different channels is pretty much the s= ame problem - just digitize (ADC) a wider bandwidth and separate in the dig= ital domain.=C2=A0 the only real issue on receive is equalization - if you = receive two different signals at different receive signal strengths, the lo= wer 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 enou= gh that you can cover that with more ADC bits (or have the MAC protocol man= age the station transmit power so that signals received at the AP are nearl= y 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:

> _______________________________________________
> Make-wifi-fast mailing list
> Make-wifi-fast= @lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/ma= ke-wifi-fast
> An AP per room/area, reducing the tx power (beacon range) has been my<= br> > approach and has scaled very well.=C2=A0 =C2=A0It does require some wi= res to each AP
> but I find that paying an electrician to run some quality wiring to th= ings
> that are to remain stationary has been well worth the cost.
>
> 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 ch= unks
>> would be a huge improvement, not many people are using them (yet),= and the
>> wide 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 up
>> needing multiple APs, or you have many stations, I expect that you= will be
>> better off with more APs at lower power, each using different chan= nels.
>>
>> 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: ma= ke-wifi-fast@lists.bufferbloat.net,
>>>=C2=A0 =C2=A0 =C2=A0"cerowrt-devel@lists.bufferbloat.net"
>>>=C2=A0 =C2=A0 =C2=A0<cerowrt-devel@lists.bufferbloat.net>
>>> Subject: Re: [Make-wifi-fast] more well funded attempts showin= g market
>>> demand
>>>=C2=A0 =C2=A0 =C2=A0for better wifi
>>>
>>>
>>> hmm, I'm skeptical.=C2=A0 =C2=A0To use multiple carriers s= imultaneously is difficult
>>> per RF issues.=C2=A0 =C2=A0Even if that is somehow resolved, t= o increase throughput
>>> usually requires some form of channel bonding, i.e. needed on = both sides,
>>> and brings in issues with preserving frame ordering.=C2=A0 If = this is just
>>> channel hopping, that needs coordination between both sides (a= nd isn't
>>> simultaneous, possibly costing more than any potential gain.)= =C2=A0 =C2=A0An AP only
>>> solution can use channel switch announcements (CSA) but there = is a cost to
>>> 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 tha= t I
>>> understand.=C2=A0 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> wrote:
>>>>
>>>>>
>>>>>
>>>> https://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wi= fi?ref=3Dbackerkit
>>>>
>>>>>
>>>>> "Portal is the first and only router specifically= engineered to cut
>>>>> through and avoid congestion, delivering consistent, h= igh-performance
>>>>> WiFi with greater coverage throughout your home.
>>>>>
>>>>> Its proprietary spectrum turbocharger technology provi= des 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-u= nit apartments"
>>>>>
>>>>> It sounds like they are promising working DFS support.=
>>>>>
>>>>
>>>> It's not clear what chipset they are using (they are c= laiming wave2) -
>>>> but they are at least publicly claiming to be using openwr= t. So I
>>>> threw in enough to order one for september, just so I coul= d 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.
>>>>
>>>>
>>>>
>>>> ht= tps://www.kickstarter.com/projects/portalwifi/portal-turbocharged-wifi/comm= ents
>>>>
>>>>
>>>>
>>>>> --
>>>>> Dave T=C3=A4ht
>>>>> Let's go make home routers and wifi faster! With b= etter software!
>>>>> http://blog.cerowrt.org
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Dave T=C3=A4ht
>>>> Let's go make home routers and wifi faster! With bette= r software!
>>>> http://blog.cerowrt.org
>>>> _______________________________________________
>>>> Make-wifi-fast mailing list
>>>> Ma= ke-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
>>
>>
>



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