From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x235.google.com (mail-oi0-x235.google.com [IPv6:2607:f8b0:4003:c06::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 252473B260 for ; Wed, 11 May 2016 14:13:07 -0400 (EDT) Received: by mail-oi0-x235.google.com with SMTP id v145so81189913oie.0 for ; Wed, 11 May 2016 11:13:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc; bh=5Yl1IbDSxchSZioKBw1SrbfUZ6Jp4PANO/R234RLBDA=; b=HcpG3vZhgGUxGB8peN7qQojFn9h/hjvUZD/4a8eem0l98nDNIHBg+Ur2KlXHYI/CqH Wzl7zgJUnUYliKMvkSdLzzh//3RK1+Y9Wdw3ci3DKCPrhZphwPKmg73ziz6VIAVfmzmM DFupdMIawPLUN0XWo9CJbr1aBZmMFRjFsizdCu8VbHeeOtni2MKr3EUxrlTDgLDPiPGo YQSQ+hNu58Z7SU2ZJWHa2CB601YRcK4oGu/Y14XxHdC6uMFK6468Lg5xKeC6GFlBia6C Ze0gF93UArPibTPv1EjHrTvXRDPARl/WXYDLZoE1v0BqZUQ1Ij4CzqFsIYaL6x6YT0+z KB8Q== 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:date :message-id:subject:from:to:cc; bh=5Yl1IbDSxchSZioKBw1SrbfUZ6Jp4PANO/R234RLBDA=; b=GwLwZRpZ1N0fZfzy0qH99Rxw91s2wCPjpr5aOsHyjOYi0cg1tP8dUyV86cyCLiC73V f51OSX89UsiFQEYixKzY6ALvnhsT+tbSOrIb8cTPz7s8Mh2AZIvoEKF47FNMh4gK7yoQ 0vG2a7/hn+7g+dGtQd05oyom8+rtVtBhqTjmrt4BnOiblAsAqoMRu5VYbIfwQhFEBW84 C8Thig+mtl7MCT+X50jL3FsH9f5btXgdOYhdPYS+SHJUyvzeKFDapy4Iv7C8D84azymx OuvJEsWIU1Nw6QLWPbmOeQ2pcMr5/UaohBc4HYuFMBe60x8UWsg2U8Lk5ZUo3xOFRU2z 30Tg== X-Gm-Message-State: AOPr4FVegXHDsKJbqpktKNSoZkYS/pt/jAbfXqPRc/yAGSqwRl42VsDP/LDECNyDgAwFYmR41YomVr2dJmWgCQ== MIME-Version: 1.0 X-Received: by 10.202.204.9 with SMTP id c9mr2552953oig.112.1462990386429; Wed, 11 May 2016 11:13:06 -0700 (PDT) Received: by 10.202.229.210 with HTTP; Wed, 11 May 2016 11:13:06 -0700 (PDT) In-Reply-To: References: <871t58n5wk.fsf@toke.dk> Date: Wed, 11 May 2016 11:13:06 -0700 Message-ID: From: Dave Taht To: Luca Muscariello Cc: David Lang , "make-wifi-fast@lists.bufferbloat.net" Content-Type: text/plain; charset=UTF-8 Subject: Re: [Make-wifi-fast] Thoughts on tackling airtime fairness 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: Wed, 11 May 2016 18:13:07 -0000 On Wed, May 11, 2016 at 9:41 AM, Dave Taht wrote: > On Wed, May 11, 2016 at 9:09 AM, Luca Muscariello > wrote: >> Correct, but in between that time and now a lot has been done in different >> areas but not much on this point. >> The fact that some part of the industry is looking at LTE-U is also because >> 802.11 standard is not good enough. > > What do you think of LTE-LAA? > > I do think very strongly that actual usage of 802.11 can be made > vastly more efficient, that we can use up a great deal of the mac > currently being left unused, and schedule txops way more efficiently - > and that I'd love to test with michal's patch set against the LTE-U > tests cablelabs, etc which did > > 100 stations before (stock): > > http://blog.cerowrt.org/flent/drr/10tothe5.svg > > after > > http://blog.cerowrt.org/flent/drr/newcode.svg Seeing "only" 250ms worth of delay for 100 stations here was what kicked off a prior thread, my understanding of a theoretical base number here would be about 70ms. (?) ... Adding in mu-mimo to the picture makes my head hurt. My understanding of how mu-mimo is supposed to work is you have to have accumulated 2-3ms worth of packets for the number of stations you are going to schedule before it's worthwhile at all. The stations are going to typically be limited to 1 antenna (most laptops have 2), I think. So a 4 antenna system *could* send to 4 stations if all have traffic pending... at a cost of a (proposed, I don't agree with it) 500 usec sounding phase every 10ms. My take on that is you should only sound when you actually have some potential to share that many flows to that many stations, sounding being more of an aspect of rate control, also. Having only 2 stations that you can mu-mimo to seems like a lose generally. Based on normal traffic behaviors the stations that could be sent to varies, and gang scheduling with lots of stations would require even more soundings... ... I don't have a lot of hope for mu-mimo, although what I kind of expect is the work done here will end up marketed as due to that feature in the wave2 stuff...