[Starlink] On FiWi

Wed Mar 15 12:09:44 EDT 2023

Hi David,

> On Mar 15, 2023, at 16:24, David Fernández via Starlink <starlink at lists.bufferbloat.net> wrote:
> 
> Hi David,
> 
> That's true: "any communications infrastructure that you mandate get
> built into new buildings is going to be obsolete long before the
> building is"

	There is some truth to that, I live in a house from 1918...

> 
> I am afraid this is also true: any communications infrastructure that
> you do not mandate to get built into new buildings will never make it
> into them afterwards.

	However the internal infrastructure was not last touched 1918... so updates are possible ;)

> 
> So, we end up having things like IAB (Integrated Access and Backhaul)
> defined to extend 5G coverage to downtown areas, where buildings
> cannot be touched for historical/artistic reasons (extreme case).
> 
> Some time ago I tried to install coaxial in a flat that had only
> copper wiring. It was impossible. Coaxial was too thick to pass
> through the hole reserved for copper telephone cable (even removing
> old cables), so I stayed with DSL. It is important that architects
> consider the cabling needs of homes, not only for electricity.

	Especially as power lines are often placed inside walls in "plaster" over here. However even for power it has long been clear that the option with long term usability is to not put the actual cables in plaster, but some flexible tubes, wide enough to allow a few parallel cables. However for telecommunication wiring things are often a bit special... like DSL-wires is best not placed cloae and parallel to power lines, fiber and things like cat8 cables have different minimal turning radii that power cables, ... all things that make it preferable to design two distribution tube systems, one for power one for comms.

> I have
> used PLC (Power Line Comms) to extend Wi-Fi coverage at multiple floor
> homes, but it is not perfect solution.

	+1; not ideal especially for VDSL (profile 35b is quite sensitive to MIMO PLC adapter which do carnage to the upper frequency sub carriers.

> I would not recommend it.
> Wireless mesh repeaters are worst, to my experience.

	Funny, over here we are still mainly VDSL based (FTTH is coming, just not very fast ;) ) and here PLC is typically less desirable than meshes of any kind.

Regards
	Sebastian

> 
> Regards,
> 
> David
> 
>> Date: Tue, 14 Mar 2023 11:37:21 -0700 (PDT)
>> From: David Lang <david at lang.hm>
>> To: David Fernández <davidfdzp at gmail.com>
>> Cc: starlink at lists.bufferbloat.net
>> Subject: Re: [Starlink] On FiWi
>> Message-ID: <8qq0r5n2-s836-1080-3362-2o8nr3qn1044 at ynat.uz>
>> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>> 
>> any communications infrastructure that you mandate get built into new
>> buildings
>> is going to be obsolete long before the building is (especially radio
>> equipment)
>> 
>> I am a big fan of using wire (or fiber) directly to equipment when you can.
>> wifi
>> is sexy and 'easy' to setup, but there is only so much airtime available,
>> and
>> your radio footprint where you produce intereference to other equipment is
>> much
>> larger than the usable footprint (let alone what your requirements are), so
>> it
>> is far more work to share reasonably. You also are sending a lot of power
>> places
>> where it's not useful, so you are wasting energy compared to having
>> somethign
>> hard-wired.
>> 
>> There are times when you need the mobility that radio gives you, and times
>> where
>> it's advantages outweigh the disadvantages, but please don't fall into the
>> trap
>> of thinking that wires are obsolete and should be discouraged, it's exactly
>> the
>> opposite, the more we can hard-wire, the better the mobile devices that
>> can't be
>> hard wired can perform.
>> 
>> David Lang
>> 
>>  On Tue, 14 Mar 2023, David Fernández via Starlink wrote:
>> 
>>> Hi Bob,
>>> 
>>> If you want that FiWi infrastructure on buildings, I am afraid that
>>> you only get it (in the long term) with a law that makes it mandatory
>>> to make new buildings with that infrastructure for communications.
>>> 
>>> In Spain, it should be added to this:
>>> https://avancedigital.mineco.gob.es/Infraestructuras/Paginas/Index.aspx
>>> 
>>> Regards,
>>> 
>>> David
>>> 
>>>> Date: Mon, 13 Mar 2023 21:27:23 -0700
>>>> From: rjmcmahon <rjmcmahon at rjmcmahon.com>
>>>> To: Sebastian Moeller <moeller0 at gmx.de>
>>>> Cc: dan <dandenson at gmail.com>, Jeremy Austin <jeremy at aterlo.com>, Rpm
>>>> 	<rpm at lists.bufferbloat.net>, libreqos
>>>> 	<libreqos at lists.bufferbloat.net>, Dave Taht via Starlink
>>>> 	<starlink at lists.bufferbloat.net>, bloat <bloat at lists.bufferbloat.net>
>>>> Subject: [Starlink] On FiWi
>>>> Message-ID: <bc1cfdf998bb6bb246a632f0dc0fe3a8 at rjmcmahon.com>
>>>> Content-Type: text/plain; charset=UTF-8; format=flowed
>>>> 
>>>> 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
>>>> 
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>> 
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