On Wed, 15 Mar 2023, David Fernández via Starlink wrote:
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.
don't mandate a specific technology, mandate paths for that technology to use.
If a building was built with wire chases for Cat 5 cable, it's usable for a lot
of different things, and it's then easier to upgrade that cat5 to some new
cables.
But if it wasn't even wired for telephone or electricity (think big stone
castles), retrofitting it in is very hard.
It will happen if people want it enough, but it helps if there is provision for
wiring to happen.
And the provision should be to each room if possible, not just to each
floor/apartment (think early telephones where there was one per house)
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).
it's more a case that the 5G band requires a huge number of nodes to operate.
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. I have
used PLC (Power Line Comms) to extend Wi-Fi coverage at multiple floor
homes, but it is not perfect solution. I would not recommend it.
Wireless mesh repeaters are worst, to my experience.
wireless mesh can work, but only if you use a different band for the uplink
communication between nodes than you use for your endpoint devices to
communicate to the nodes. People try to use the same band for both and it just
doesn't work.
David Lang
Regards,
David
Date: Tue, 14 Mar 2023 11:37:21 -0700 (PDT)
From: David Lang <[email protected]>
To: David Fernández <[email protected]>
Cc: [email protected]
Subject: Re: [Starlink] On FiWi
Message-ID: <[email protected]>
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 <[email protected]>
To: Sebastian Moeller <[email protected]>
Cc: dan <[email protected]>, Jeremy Austin <[email protected]>, Rpm
<[email protected]>, libreqos
<[email protected]>, Dave Taht via Starlink
<[email protected]>, bloat <[email protected]>
Subject: [Starlink] On FiWi
Message-ID: <[email protected]>
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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