From: Mike Puchol
[mailto:mike@starlink.sx]
Sent: Wednesday, July 28, 2021
1:16 AM
To: 'Karl Auerbach';
starlink@lists.bufferbloat.net;
Subject: Re: [Starlink] Intro and
a question
I won’t pound on the dead donkey too much, Dick is way above my
pay grade on this one, but I’ll just add that multiple polarization
schemes were explored in the LTE world when they wanted to move from 2x2 MIMO
(achieved with cross-polarized antennas) to 4x4 and higher orders. They just
couldn’t make it work, so efforts were abandoned - it’s too hard to
achieve the physical separation the “invention” claims through any
practical means, which is where Carlos goes into “… and I’ll
need a big pocketed investor to prove this works”. Billions have been
spent on research for CDMA, LTE and 5G, and nothing in the polarization space
has ever been marginally achieved.
[RR] The reason is once again the laws of physics! Polarization
is a two-dimensional subspace of three-dimensional space … think Pointing
Vector = E x B, and you will rapidly realize claims of infinite capacity from
an infinite number of polarizations is nonsense. As for not being able to
make 4x4 work, it’s because the people
implementing it really do not understand space-time signal processing applied
to wireless telecommunications and real antennas (and the same may be
true of Starlink .. not enough available info to tell yet:^((() And when you add
to that confusing signal spaces with physical 3-D space as Carlos does in
his rant, you get BS on BS, or BS-squared. All that aside, what we really
want, Dave, is the name of the guy who invests in Carlos’ scheme … he/she
obviously has money to burn!
Then, considering you only have a single path between a satellite and a ground
station, any claims of higher-order MIMO through physical separation are void.
[RR] See above highlighted text! And just know that you are
thinking that physical separation has to mean “of the antennas at a
single receiving or transmitting unit” and there are “other
physical separations that are definitely relevant”. “Higher-order
MMO” does NOT require large physical separations however, just smart
signal processing. Do it right and, under the appropriate conditions/assumptions,
the capacity of a channel of bandwidth W between the satellite with M antennas and
ground station with N antennas) goes up by W*log2(M^2 * N^2) over that of a
single antenna at each end. For example, if M = 16 and N = 4, the increase
is 12W! Point is: MIMO does not necessarily mean multiple spatial
streams, it means multiple inputs and multiple outputs. The two are NOT
the same! He physical channel between the inputs and outputs really matters.
RR
Best,
Mike
On Jul 28, 2021, 02:00 +0200, Dick Roy <
Even better, this guy's BS goes back to the late 80's when Qualcomm was
promising 1000 times AMPS in cellular capacity with their new CDMA
technology! Fast forward, CDMA has disappeared from planet earth as a
cellular technology ... and 3 major telecommunications manufacturers are out
of business!!
RR
-----Original Message-----
From: Starlink [mailto:starlink-bounces@lists.bufferbloat.net] On Behalf Of
Karl Auerbach
Sent: Tuesday, July 27, 2021 4:09 PM
To: starlink@lists.bufferbloat.net
Subject: Re: [Starlink] Intro and a question
On 7/26/21 8:51 PM, Larry Press wrote:
https://spacenews.com/tech-breakthrough-morphs-gigabit-wifi-into-terabit-sat
ellite-internet/
<https://spacenews.com/tech-breakthrough-morphs-gigabit-wifi-into-terabit-sa
tellite-internet/>
Wow! I got massive deja vu and thought had to check whether I was
reading a 1970's copy of the JC Whitney Catalog!
(Or my own CaveBear Catalog - of hyperbolic bogus network stuff: "If we
have it, you don't need it"), most particularly:
- Our Press Release from one of the Interop shows, people actually
believed this!! Gaga Net:
https://www.cavebear.com/cb_catalog/techno/gaganet/ )
- The Maximum Momentum Router:
https://www.cavebear.com/cb_catalog/current/maxmoment/
(For those who don't remember, the JC Whitnet catalog was filled with
things for your car that would improve gas milage by a zillion percent
or bump horsepower by 200hp. With that catalog one could turn an old
1200cc VW bug into a flame breathing monster, or so one would if one
accepted the hyperbole.)
OK, let's accept this guy's claims as true. Do they make an end-to-end
difference?
Perhaps if the satellite part of the end-to-end path is truly a bit
synchronous "bent-pipe". But Starlink seems to be evolving far past
that simple bit-clocked-circuit model into something more resembling a
space internet with routers, or at least a switched network that could
have issues such as choice of route, multiple inputs feeding into one
output (in other words, potential congestion).
BTW, I did like the article's phrase "High Definition Internet" - It
immediately called to mind "Brawndo - it's got electrolytes" (from
the
movie Idiocracy.
--karl--
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