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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