From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) (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 072E03CB35; Mon, 27 Aug 2018 15:45:59 -0400 (EDT) Received: by mail-lf1-x133.google.com with SMTP id g9-v6so148232lfh.1; Mon, 27 Aug 2018 12:45:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=PAOe0GB64iPys0p9d7TZb4iMwLxuNgp75sTO85fb7Nc=; b=IQXu2SDHuFZ39kqVNnWBtuuzufzTh3eGmplZBiltdChFhGK9cVD1HRiExzTMsavsJ8 qYxjTnpUYE5BEV6pXYzhVAtkvNpif8QbmxYTfBBYTYd7D0SpuKcy0iFmwfACyqBp9aGb e7rf/lW7Wfn7bA07FtaXLiPcbO95+u2w14ypmgvDSsg9XDMPWkkcVg3A6+jN+CDuEfTB jLv+6yGrwT4FegJsMVTjotBawUBB2ZMmPpL5r3sDY5Q+Tbtgh2HKSsCwY8ESyDe3g3fS Lod/Mnd48imveMoT7ry8e2Y0s56/D2CVnRYOLcgrjO3JhzAgL8nky/i2PRb1djLhpM/C UTrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=PAOe0GB64iPys0p9d7TZb4iMwLxuNgp75sTO85fb7Nc=; b=FRDqcL9S+W9qK/nVO7KMx/bFltKjNN33pOM56oYz+QEVPt+fUbkC0USrFJh3x+Siqb 9F9a1mSaFa6YiDi04yOMzNxNhifM5/wQD6OayOOunk5zLdjiWgeKwMMe+5ILHZYjPLPc 7OHxrU2K/obdYnJ9Iamp1wF3a6gp5WBFHZZmabgXlcVzbp2cNBjKrULI1rhZS7ZnZgNU kTLm6XO+tfhtMJXoQxgRYWwVwWTHGZSJ2XA1mUrxtyRBtltisCsB2A/dBcbi+AStVKcJ /lc+59tDH5h5yJKwFVyZ5JNKN74cJ7W+dc2ia7krfh5cx/N9fMj3GsQaEFRuIMLudelu kf1g== X-Gm-Message-State: APzg51DVrntrPE4ao3rkkZbTUZI0xhOktDTs2mikEZMIQrSEaQxuyxNq LMnNk/RpW3oCxQ3bQ3SQYas= X-Google-Smtp-Source: ANB0VdZA+kfqW0sHYciD0oowsJvkd6aVDMXpfvaTmCqk6XigifyfceFNJI93z77gWB1tVdI7ln99jw== X-Received: by 2002:ac2:418b:: with SMTP id z11-v6mr8872899lfh.3.1535399158832; Mon, 27 Aug 2018 12:45:58 -0700 (PDT) Received: from jonathartonsmbp.lan (83-245-238-14-nat-p.elisa-mobile.fi. [83.245.238.14]) by smtp.gmail.com with ESMTPSA id h4-v6sm14877lfj.69.2018.08.27.12.45.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Aug 2018 12:45:58 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) From: Jonathan Morton In-Reply-To: Date: Mon, 27 Aug 2018 22:45:56 +0300 Cc: dpreed@deepplum.com, bloat-announce@lists.bufferbloat.net, Make-Wifi-fast , cerowrt-devel@lists.bufferbloat.net, bloat Content-Transfer-Encoding: quoted-printable Message-Id: References: <1535286372.35121837@apps.rackspace.com> <2282D31E-CBEF-4B42-A6A6-4D6394EE0DF7@gmail.com> To: Bob McMahon X-Mailer: Apple Mail (2.3445.9.1) Subject: Re: [Bloat] [Make-wifi-fast] [Cerowrt-devel] closing up my make-wifi-fast lab X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Aug 2018 19:46:00 -0000 > On 27 Aug, 2018, at 10:11 pm, Bob McMahon = wrote: >=20 > I guess my question is can a WiFi transmitting device rely on = primarily energy detect and mostly ignore the EDCA probability game and = rather search for (or predict) unused spectrum per a time interval such = that its digital signal has enough power per its observed SNR? Then = detect "collisions" (or, "superposition cases" per the RX not having = sufficient SINR) via inserting silent gaps in its TX used to sample ED, = i.e. run energy detect throughout the entire transmission? Or better, = no silent gaps, rather detect if there is superimposed energy on it's = own TX and predict a collision (i.e. RX probably couldn't decode its = signal) occurred? If doable, this seems simpler than having to realize = centralized (or even distributed) media access algorithms a la, TDM, = EDCA with ED, token buses, token rings, etc. and not require media = access coordination by things like APs. The software might be simpler, but the hardware would need to be = overspecified to the point of making it unreasonably expensive for = consumer devices. Radio hardware generally has a significant TX/RX turnaround time, = required for the RX deafening circuits to disengage. Without those = deafening circuits, the receivers would be damaged by the comparatively = vast TX power in the antenna. So in practice, it's easier to measure SNR at the receiver, or = indirectly by observing packet loss by dint of missing acknowledgements = returned to the transmitter. - Jonathan Morton