From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bobcat.rjmcmahon.com (bobcat.rjmcmahon.com [45.33.58.123]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 6A5EE3B29E; Tue, 14 Mar 2023 00:27:24 -0400 (EDT) Received: from mail.rjmcmahon.com (bobcat.rjmcmahon.com [45.33.58.123]) by bobcat.rjmcmahon.com (Postfix) with ESMTPA id 75D741EEE8; Mon, 13 Mar 2023 21:27:23 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 bobcat.rjmcmahon.com 75D741EEE8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rjmcmahon.com; s=bobcat; t=1678768043; bh=fnBazCEi/XNlSxB9l1/3dXAQY4XlVOvCn0gsOVWrdRw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bPQJ0pkNWnu00sv2V5WIxHDN13pAS2wR5wfBSN6rhkzPV8CKwZwMrAemMlOaeuTgN DQZbIwNaQ8geZxUgRi9FUJkE3QoUuSG/2C5lgQIpxb4teEVekWHVY4bdrVAextCElA RqESSl5k4eVvm84CLKQROJ177upn8rvQ71FPgd9c= MIME-Version: 1.0 Date: Mon, 13 Mar 2023 21:27:23 -0700 From: rjmcmahon To: Sebastian Moeller Cc: dan , Jeremy Austin , Rpm , libreqos , Dave Taht via Starlink , bloat In-Reply-To: <5e0cd693c4749d128dbb48d6c1129071@rjmcmahon.com> References: <1672786712.106922180@apps.rackspace.com> <77CCAD19-07E0-4F9E-88C1-D207CF7BF376@cable.comcast.com> <83ffc0dad19e3343e49271889369cefc@rjmcmahon.com> <3CD0B9E6-0B2A-4A70-8F53-ED0822DF77A6@gmx.de> <13DE6E53-665F-4C20-BBE2-70E685421E9D@gmx.de> <22C819FA-DDD7-4B9B-8C09-8008D4273287@gmx.de> <5e7fac51071bdbb20837e72e7eedfc7c@rjmcmahon.com> <3f45d2a0b6e46d7b2775fb801e805f93@rjmcmahon.com> <70F71290-C6CB-4D19-8A88-F0F17C0BDDA2@gmx.de> <5e0cd693c4749d128dbb48d6c1129071@rjmcmahon.com> Message-ID: X-Sender: rjmcmahon@rjmcmahon.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: [Rpm] On FiWi X-BeenThere: rpm@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: revolutions per minute - a new metric for measuring responsiveness List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Mar 2023 04:27:24 -0000 To change the topic - curious to thoughts on FiWi. Imagine a world with no copper cable called FiWi (Fiber,VCSEL/CMOS Radios, Antennas) and which is point to point inside a building connected to virtualized APs fiber hops away. Each remote radio head (RRH) would consume 5W or less and only when active. No need for things like zigbee, or meshes, or threads as each radio has a fiber connection via Corning's actifi or equivalent. Eliminate the AP/Client power imbalance. Plastics also can house smoke or other sensors. Some reminders from Paul Baran in 1994 (and from David Reed) o) Shorter range rf transceivers connected to fiber could produce a significant improvement - - tremendous improvement, really. o) a mixture of terrestrial links plus shorter range radio links has the effect of increasing by orders and orders of magnitude the amount of frequency spectrum that can be made available. o) By authorizing high power to support a few users to reach slightly longer distances we deprive ourselves of the opportunity to serve the many. o) Communications systems can be built with 10dB ratio o) Digital transmission when properly done allows a small signal to noise ratio to be used successfully to retrieve an error free signal. o) And, never forget, any transmission capacity not used is wasted forever, like water over the dam. Not using such techniques represent lost opportunity. And on waveguides: o) "Fiber transmission loss is ~0.5dB/km for single mode fiber, independent of modulation" o) “Copper cables and PCB traces are very frequency dependent. At 100Gb/s, the loss is in dB/inch." o) "Free space: the power density of the radio waves decreases with the square of distance from the transmitting antenna due to spreading of the electromagnetic energy in space according to the inverse square law" The sunk costs & long-lived parts of FiWi are the fiber and the CPE plastics & antennas, as CMOS radios+ & fiber/laser, e.g. VCSEL could be pluggable, allowing for field upgrades. Just like swapping out SFP in a data center. This approach basically drives out WiFi latency by eliminating shared queues and increases capacity by orders of magnitude by leveraging 10dB in the spatial dimension, all of which is achieved by a physical design. Just place enough RRHs as needed (similar to a pop up sprinkler in an irrigation system.) Start and build this for an MDU and the value of the building improves. Sadly, there seems no way to capture that value other than over long term use. It doesn't matter whether the leader of the HOA tries to capture the value or if a last mile provider tries. The value remains sunk or hidden with nothing on the asset side of the balance sheet. We've got a CAPEX spend that has to be made up via "OPEX returns" over years. But the asset is there. How do we do this? Bob