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<blockquote type="cite"
cite="mid:alpine.DEB.2.20.1712180848460.8884@uplift.swm.pp.se"><br>
<blockquote type="cite" style="color: #000000;">What I actually
wanted to posit in relation to that is that one could get sooner
a c-cabable backbone sibling by marrying two ideas: the airborne
concept ongoing as outlined plus what NASA is planning to bring
about for the space backbone, e.g [1][2]. It's laser based
instead of directed radio-wave only. Sure, both is in the speed
range of c, apparantely, laser transmission has in addition a
significantly higher bandwidth to offer. "10 to 100 times as
much data at a time as radio-frequency systems"[3]. Attenuations
to photons in clean atmospheric air are neglible (few mps -
refractive index of about 1.0003), so actually a neglible
slowdown - easily competing with top notch fibres (99.7% the
vacuum speed of light). Sure, that's the ideal case, though, if
cleverly done from the procurement of platforms and overall
system steering perspective, might feasible.
<br>
</blockquote>
<br>
Todays laser links are in the few km per hop range, with is easily
at least one magnitude shorter than radio based equivalents.
<br>
<br>
</blockquote>
Hold on! This is a severe oversimplifcation, isn' it. The devices
you're probably referring to are in the low-end segment,
dillentically and maybe terrestrially operated only - to mention a
few limiting factor conceivable possibly being perceived. <br>
<br>
Certainly, there are range limiting factors when fully submerged in
the near-ground atmospheric ranges. E.g. in the darkest snow storm,
one cannot expect optics to be reliablly working - admitting that.
Nothwithstanding, recent research[1] showed astounding achievements
of FSOs even in harsh atmospheric conditions - "up to 10 gigabits
per second" while in vivid movement, in heavy fog ... for a single
pathed laser.<br>
<br>
90% mass of the atmosphere is below 16 km (52,000 ft), therefore
also most of it's randomness[2]. Meaning, one only had to surpass
this distance to more decently unfold the capabilities of an
airborne backbone. Therefore, a hierarchy of airborne vessels might
be necessary. Might smaller, more numerous ones gatewaying the
optics out of the dense parts of the atmosphere to the actual
backbone-net borne lasers, might by doing this relaying not laser
beam based. Far more mitigation techniques are conceivable. From
there on, the shortcomings appear controllable.<br>
<br>
<blockquote type="cite"
cite="mid:alpine.DEB.2.20.1712180848460.8884@uplift.swm.pp.se">I
don't know the physics behind it, but people who have better
insight than I do tell me "it's hard" to run longer hops (if one
wants any kind of high bitrate).
<br>
</blockquote>
If one looks up what is achievable in space, where the conditions
shouldn't be too different from earth atmosphere over 16 km.
Thousands of kilometres for a single hop, single path. Now imagine a
decent degree of multipathing.<br>
<br>
Physical intricacies are certainly a headache in this topic, though
shouldn't be decisive, I'd dare to categorize the largest complexity
compartment of such a system into the algorithmics for steering,
converging or stabilizing the airborne components, directing the
optics problerly and in time. The overall automatic or even
autonomic operations to abstract it.<br>
<br>
Probably, me forming some papers wrapping this up would be
worthwile.<br>
<br>
[1]<a class="moz-txt-link-freetext" href="https://phys.org/news/2017-08-high-bandwidth-capability-ships.html">https://phys.org/news/2017-08-high-bandwidth-capability-ships.html</a><br>
<p>[2]<a class="moz-txt-link-freetext" href="https://arxiv.org/pdf/1705.10630.pdf">https://arxiv.org/pdf/1705.10630.pdf</a><br>
</p>
<pre class="moz-signature" cols="72">--
Besten Gruß
Matthias Tafelmeier
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