Theoretically, Starlink should be faster cross country than terrestrial fiber.
Joe McGuckin
ViaNet Communications
joe@via.net
650-207-0372 cell
650-213-1302 office
650-969-2124 fax
“In Theroy” – ROFL
Don’t get me wrong it would be awesome if that turns out to be the case.
Hi,
Startlink 1.0, probably will not have lower latency vs Fiber (either cross country or across oceans)
Once the laser based inter-sat links are running (Starlink 2.0?), it should be lower latency vs Fiber.
With ground stations only:
With laser links:
-Harry
When there is no clouds.
This is why adaptive coding and modulation systems exist. Also dynamic channel size changes and advanced computationally intensive FECs.
You don’t think people working on microwave band projects above 10GHz with dollar figures in the hundreds of millions are unaware of basic rain fade and link budget methodology, do you?
In my experience, all that ACM has achieved is that when link becomes "slow" and if it rains outside, it means that it will be down completely after few seconds.
Previously with CCM or DVB-S without 2, it simply disappear without warning.
And yes, I have and cheap and expensive Microwaves >10Ghz too.
ACM/VCM really helps if you want to live on the edge, milking each db, (edge of link budget, e.g. small antenna size, interference), and this is actually very important to increase profitability, especially in case of multipoint VSAT, but it is near useless against rain fade.
“no clouds” is overstating the effect somewhat. I’ve operated a number of mission critical Ku band based systems that met four nines of overall link uptime. The operational effect of a cloud that isn’t an active downpour of rain is negligible. Continual overcast of clouds is not much of a problem at all, it’s active rain rate in mm/hour and its statistical likelihood, climate parameters of the location.
Yes, during rain fade events, current generation VSAT modems will drop all the way down to BPSK 1/2 code rate to maintain a link, with corresponding effect on real world throughput in kbps each direction, but entirely dropping a link is rare.
BPSK 1/2 is quite extreme. In my case it was 32APSK 8/9 at 36Mhz transponder
(yes it was quite large antenna), ~140Mbit, so switching to 1/2 BPSK will make it
~16Mbit/s, which is pretty useless for telco purposes.
For corporate, end-users, with QoS - it can be ok, but still depends on climatic zone.
Remember, it is not downlink only issue, but uplink too. And depends on antenna elevation angle
as well.
Even for end-user it is not fun to have 1/10 of capacity, most likely means unable to do
video conferencing anymore, for few days, just because it is few rainy days.
And as Ku is often covering specific regions, often it means rainy days for most transponder customers.
This is why in zones closer to equator, with their long-term monsoon, C-Band was only option,
no idea about now.
The most noteworthy thing I’m seeing in C band these days, is many customers formerly 100% reliant upon it shifting their traffic to newly built submarine fiber routes.
In much of Africa, the largest satellite TV provider has been running on
Ku-Band into homes for several years now.
I'm not sure if they still support C-Band services for specialized
requirements. But all consumers have been on Ku-Band for a while now.
Heavy rain does cause outages, but overcasts do not.
If you are lucky to have an FTTH service and you are hit with rain, you
can turn to their app and stream the same live channels while the rain
falls.
Mark.
Before most of Africa had submarine fibre, a lot of our traffic was
carried on C-Band.
In the decade preceding the arrival of submarine fibre, we reduced costs
by moving to Inclined Orbit satellites, which were mainly operated on
Ku-Band. So outages due to rain were a normal and accepted part of doing
business. ISP's that maintained C-Band satellites survived rain fade,
but had much higher operating costs.
Nowadays, satellite services are generally used in remote locations, and
for specific applications. Submarine fibre is the norm.
Mark.
I understood it's not clear if this will ever happen. In local
constellation it might, but supposedly technology does not currently
actually exist to do it between constellations. I don't understand the
topic at all, but I got impression that the precision of timing and
accuracy of aiming needed is actually a very hard problem.
But agreed, should sat2sat communication become possible, there are
many legs where starlink latency will improve upon terrestrial.
Any idea what network protocol(s) used with Starlink?
Watching the growth of terrestrial fiber (and PTP microwave) networks going inland from the west and east African coasts has been interesting. There’s a big old C-band earth station on the hill above Freetown, Sierra Leone that was previously the capital’s only link to the outside world. Obsoleted for some years now thanks to the submarine cable and landing station. I imagine they might keep things live as a backup path with a small C-band transponder MHz commit and SCPC modems linked to an earth station somewhere in Europe, but not with very much capacity or monthly cost.
The landing station in Mogadishu had a similar effect.
The early years of submarine fibre in Africa always had satellite as a
backup. In fact, many satellite companies that served Africa with
Internet prior to submarine fibre were banking on subsea and terrestrial
failures to remain relevant. It worked between 2009 - 2013, when
terrestrial builds and operation had plenty of teething problems. Those
companies have since either disappeared or moved their services over to
fibre as well.
In that time, it has simply become impossible to have any backup
capacity on satellite anymore. There is too much active fibre bandwidth
being carried around and out of/into Africa for any satellite system to
make sense. Rather, diversifying terrestrial and submarine capacity is
the answer, and that is growing quite well.
Plenty of new cable systems that are launching this year, next year and
the next 3 years. At the moment, one would say there is sufficient
submarine capacity to keep the continent going in case of a major subsea
cut (like we saw in January when both the WACS and SAT-3 cables got cut
at the same time, and were out for over a month).
Satellite earth stations are not irrelevant, however. They still do get
used to provide satellite-based TV services, and can also be used for
media houses who need to hook up to their network to broadcast video
when reporting in the region (even though uploading a raw file back home
over the Internet is where the tech. has now gone).
Mark.
When we started TICSA (Internet Africa/Verizon/whatever), we went with a 9600 bps satellite link to New Jersey specifically because the SAT-2 fibre had just been installed and traffic was being moved off satellite. The satellite folk were getting *very* nervous, and gave us a heavily discounted service provided we had a 5-year contract that specified that they service *had* to run over satellite. Job insurance.
As our requirements grew, we added fibre connections. Eventually the telco canceled the satellite connection as they were starting to focus on VSAT.
paul
There's no denying... they well-and-truly made their money :-).
If I think back to what we paid for 192Kbps up, 320Kbps down, it may
make all the grown folk on this list cry in :-).
Mark.
I don't think traditional satellites have much future as backbone. Only as broadcasting media.
Most are still acting as dumb RF converters, but we can't expect much more from them.
On geostationary orbit, it is not only expensive to bring each additional kg, but also they
need to keep it simple as possible, as it is all above van allen belt, and it needs to run there
without any maintenance for 7+ years.
So if SpaceX managed to squeeze in their satellites at least basic processing (and seems they did),
it will improve satellite capabilities (and competitiveness) greatly.
The only thing i hope, if they had space for some M2M IoT stuff, similar to ORBCOMM.
For the IoT/M2M stuff that doesn’t require huge amounts of data, there is a Silicon Valley startup that is deploying cube sats for just that.
Swarm Technologies
-Mike
Does anyone know of (m)any satellite TV services delivering 1080p or
greater? The most I've seen on our side of the rock is 1080i.
If there is an inherent commercial restriction in how many pixels we can
grab over satellite at scale, it might be tricky for some markets that
demand 1080p, 4K, or greater, for linear TV.
Mark.