Satellites Are Becoming the New Cellphone Towers
spectrum.ieee.org
spectrum.ieee.org
Edit: I didn't mean to focus on Starlink specifically. Eventually it won't just be Starlink up there, and likely our mobile devices will need less and less power to communicate with those satellites. So I'm less interested in the effects of Starlink and more on satellite communications generally.
[1]: https://www.itweb.co.za/article/icasa-takes-note-of-illegal-...
Isn't that's how Ukraine got fucked. Sent their submarine drones towards Crimea but as soon they crossed the "border" they lost signal. They tried to contact Musk and the rest is history...
Maybe more interesting is the question why they need Starlink at all? Why are they dealing with a private for profit company when the US military could provide them with satellite communications?
The problem is that the consequences of accidentally providing service to Russia, a country that is both sanctioned by the US (so Starlink would face headache-inducing legal problems in the US) and is conducting an offensive invasion (which matters because it's against Starlink policy), are considered far too high for the Pentagon to approve it without the use of hexagon geofencing. This hexagon geofencing means it's not as useful for crossing over the Russia-Ukraine front line. It is updated frequently to reflect the situation on the ground, but they can only provide service to a hexagon if all of that land has been taken back from Russia, so it will never quite satisfy how fast Ukrainian soldiers would prefer the geo-fencing to update.
It's likely that Starlink wants to refine this geofencing to be useful for Ukraine's cross-border counteroffensives, or to use some other measures to ensure the captured equipment and signals are not useful for Russia, but as long as the US Government says no, it won't happen.
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^1: There was some usage of the service before it was properly approved, which was around the time Elon Musk was publicly saying Starlink wouldn't support counteroffensives and blocked off access in Crimea. But this is history now as Starlink is obligated by the Pentagon to support Ukraine, Musk's opinions do not appear to be guiding Starlink's current policies. Unfortunately this series of events has spawned some really confused news articles, angry Ukrainian soldiers on social media, and various partisan nonsense... the publicity and drama of it all pretty much overshadowed what actually ended up happening, which could have been much more interesting to investigate by anyone who is pro- or anti-ukraine, or pro- or anti-Musk -- or just anyone who is interested in how these military contracts work.
Most users use 4G
Every battlefield company in Ukraine has at least two.
enlighten yourself a bit on recent Crimea history:
https://www.wilsoncenter.org/publication/why-did-russia-give...
Mariupol had starlink, it doesn't today. Can you guess why?
https://theconversation.com/the-manipulation-of-the-american...
If I were in charge, I'd try to get licensed and be able to collect money from customers there.
I wonder what will happen now that every phone will become a sat phone.
Governments that don't want that will disallow the sale of such phones inside their country unless the manufacturer disables the satellite features for customers there.
Sure, some will get through via illegal imports, but largely this will be effective.
At that point, you could only request that phone manufacturers retroactively provide firmware updates that ban these networks, or maybe make it hard to get SIMs allowed to connect to them (but then there's eSIMs too).
I think in practice we'll see a combination of these countries applying legal/economical pressure on the operators and jamming, with larger/less isolated countries leaning on the former, and the others on the latter.
Hypothetically, in the event of a war or similar unrest, the US could use satellite cell 'towers' to give an entire country limited connectivity with old devices people have stashed away in some drawer or closet without otherwise active cell plans, which are therefore off the local government's radar. People could be coerced to turn over the phones the government knows about but still retain some connectivity.
India routinely does total communications blackouts, so the satellite phone ban is unsurprising, in that context.
https://news.ycombinator.com/item?id=20701204 ("India Shut Down Kashmir’s Internet Access")
https://news.ycombinator.com/item?id=10126931 ("India turned off mobile internet for 63M citizens amid protests in Ahmedabad")
https://news.ycombinator.com/item?id=25972620 ("India protests: Internet cut to hunger-striking farmers in Delhi")
https://en.wikipedia.org/wiki/2019%E2%80%932021_Jammu_and_Ka... ("2019–2021 Jammu and Kashmir lockdown")
If you don't have enough things to worry about: the US has exactly the same legal powers—in fact they're national security powers the President can invoke unilaterally,
https://techcrunch.com/2020/10/22/representatives-propose-bi... ("Representatives propose bill limiting presidential internet ‘kill switch’")
I'm not in the US so I don't worry about that. But the US doesn't seem to actually use it as India does.
And besides I have other communications options if that would happen.
Also: https://travel.stackexchange.com/questions/64974/why-are-sat...
I've had this idea on my mind for quite a while now, because some time ago I heard something about Starlink painting their satellites black, which reminded me of the "it's hotter in a black car" thing.
That's usually how governments control businesspeople.
(https://www.washingtonpost.com/climate-environment/2023/07/1...
https://conservancy.umn.edu/handle/11299/171701
https://www.smh.com.au/world/north-america/toxic-secrets-the...)
Sounds like standard live and learn tech development, like nuclear.
I could see such a regulation be implemented for new phones (Apple's Globalstar functionality is already deactivated in software based on geolocation in non-supported countries and maybe even in hardware for models sold in some regions), but it won't help with existing devices.
Another avenue would be restricting access to SIMs capable of logging on to these networks. SIMs have supported mutual authentication since (I believe) 3G, so it's not possible for a satellite 4G service to provide "unilateral roaming".
China's BeiDou would have to probably be approved through a treaty since it's run by their military, it's not going to happen. I've been told by someone who used to work at space force that beidou can be used to track users, but that's bullshit with how our receivers use it. Here's a US gov report on the matter, if it's receive only (no messaging component) tracking isn't going to happen https://www.uscc.gov/sites/default/files/Research/Staff%20Re...
Finally, the way at least Qualcomm receivers work is they will only lock to GPS first and then mix in the other constellations (at least while in CONUS).
Also, is there any hope for "authenticated GPS" to prevent spoofing? Is that even technically possible for non-secret codes like C/A or L5?
Those who are, at least for now, within good graces are of course exempted. Those who are systematically repressed can be systematically, specifically, and/or arbitrarily detained, investigated, and/or prosecuted, as suits political needs.
And the fact that the actions are based on at least nominal basis in law and procedure means that the practice is defensible both to those tasked with enacting it and with the institutions and general public. Even tyrants find that power is best and most readily exerted through cooperating and existing channels.
A prime example: On a highway leading from Chechnya to Dagestan there is a traffic light. It is always red. https://en.rattibha.com/thread/1595456040677556226
That said the only people who will be able to afford the dish and service will likely be people who are in bed with the government or vise-versa...
It's not that hard if you're really committed and can accept chasing up offenders after-the-fact.
Countries that consider banning Tesla due to Starlink, would be effectively holding back their EV market.
But it is effective in most other countries where they operate
Not true. Both the transmitter and receiver (in both directions) utilize phased arrays. This means the receiver is very good at rejecting noise angularly separated from the expected location of the transmitter. Geometry dictates that jamming could be somewhat effective against upload (i.e. if the jammer is located roughly within the size of a spot beam from the transmitting dish), but is almost completely ineffective in the download direction.
This is all fairly theoretical since much of the details aren't publicly available; but as evidence I point to the fact that Russia has poured a huge amount of money into EW and, despite having considerable motivation to deny Starlink access, has consistently failed to prevent its widespread use by Ukrainian troops on frontlines mere kilometers from its own forces.
But on common mobile devices, you only have two or four antennas, so the beamforming gain is much more limited. Having more than one antenna there is mostly done to leverage multipath propagation in a non-line-of-sight environment for capacity gains as far as I understand it, and in a line-of-sight environment, you only get very moderate steering gains of a few dB (and practically no steering/beamforming effect). Satellite communication is primarily line-of-sight, though.
So while the satellite can steer its beams towards a given mobile device (both for transmit and receive), and this allows for higher spectral efficiency and better use of the satellite's transmit power and better noise rejection, the mobile device can't do the same and will easily be overwhelmed by a jammer at least in the downlink path, as far as I understand.
While Iran isn't tiny (17th largest country), the satellites have several other territories nearby by that could use up the capacity that a no-Iran rule makes available.
In addition, as others have mentioned, companies do not like to take on whole countries unless perhaps it is a very small and irrelevant one.
Starlink direct to cell will still cover huge areas per cell which is great for remote areas but not for high density like cities. It will not have strong enough signals to penetrate buildings. And it won't provide enough bandwidth for more than texts at least not for now.
It's an augmentation of the land based service, not a replacement.
Hopefully this will bring back website that is focus being on being lightweight, and just display information (or gemini type of alternative), and discourage the SPA development fiasco that has happened.
Not 'back'. This is normal for satellite data other than static Starlink installs with their huge antenna. The iridium Go! Hotspot does about 2400 bps :) they also have a new note expensive version that does up to 88 kbps download and 22 up. Still dialup speed so?
If you download all the UI elements, layout, and styling up-front, and then only have to communicate with the server to fetch structured data that tells the app how to change the user interface, that's strictly better.
The issue, of course, is that most pages (regardless of whether they're SPAs or not) require a large amount of bandwidth to download assets.
But I would expect that a low-bandwidth SPA would be more responsive than a traditional low-bandwidth website where it has to reload the full page every time you do something.
Or - as a user - the LocalCDN addon
That said — can you imagine deploying your service to ~5200 satellites? yikes
I got a iPhone 14 for a backup satellite sos method.
In Canada there are 100s of km of roads between towns with zero cellphone service, often for hours at a time. Having space based communication in a cellphone to fall back on would be extreme valuable and life saving to many. I know I already pay a bundle for it and many of my outdoorsy friends do the same. I can be driving to a friends house a few hours away and be out of signal for half of it, being able to call for help if I encounter or get into an accident is pretty important and building cell towers would be far more expensive then some satellites
If you could clarify- is this data like mobile data/internet, or data in a literal sense? Because if you’re SMSing your GPS coordinates to a friend’s phone you could stick to only SMS.
you get a link you can share with people that brings up a map showing your location & track
Historic.
Cell coverage is simply is never going to happen for these areas and the roads to get to them as the telecommunication company will never recoup their costs.
Another thing to consider is how much the bands dedicated to cell phones are already saturated in dense urban environments. I don't see how a few thousands satellites would be able to scale if they were to replace our actual cell towers (some of them consisting of local cells on utility poles, etc.).
And also, satellites dedicated to search and rescue to locate emergency beacons already exist, and you don't need many of them to cover the whole planet.
That's what 5G is supposed to be for. In dense areas, there are supposed to be a large number of tiny cells operating in the 5GHz-6GHz range. The main application for this is stadiums, so the fans can be getting video on their phone while watching, or not watching, the dame. Most of the NFL stadiums now have this.
Other parts of cities, not so much yet.
The power requirements and thus the bulky batteries of existing satellite phones could be reduced by switching to protocols which trade off bandwidth for higher error correction abilities through encoding and I don’t think existing satellite phones use the most bandwidth efficient encoding available so that could be another improvement.
There’s still the free space path loss between the surface of earth and a Globalstar or Starlink which my best guess estimate is in the order of 130db (can anyone more knowledgeable share a better estimate? I assumed bottom end of L-band, a height between Starlink and Globalstar, and used unverified dBi values for antennas at both ends).
Then there’s latency but I don’t think that’s a show stopper for many common use cases of voice and data.
No, you can’t trade bandwidth against error correction. What you can do is use channel coding/error correction to trade effective signal-to-noise strength against data rate (at constant power).
But since your data rate demand is fixed for voice, and the uplink transmit power is fixed too (by 4G/5G specs), you need to raise the received signal strength. The only thing that can help you there are more directional receive antennas on the satellites, which is what these new generations are doing.
Bandwidth is the actual number of kilo/mega/gigahertz the signal occupies on the spectrum and is largely a function of symbol rate, but the actual data rate has many more variables.
More bandwidth does not help you get a better data rate if you’re power limited. In the case of satellite communications you basically always are, and bidirectionally so when it’s to mobile/battery-powered devices.
Although pratically you can do that only so far, because you're going to be limited by the bandwidth of your receiver.
Practically, satellite communications are power-limited and accordingly will always be so close to the noise floor (i.e. S/N << 1) that the logarithm can be approximated with a constant and the bandwidth dependency is negligible and drops out of the equation.
It only matters in the bandwidth-limited regime, i.e. for S/N >> 1.
I don't have the exact S/N numbers for these systems, and there might well be some potential gain that's not being exploited for reasons of spectral efficiency (after all, these systems want to serve multiple phones at least somewhat efficiently).
The spectrum is limited in any case, both by receiver capabilities and the fact that it's a very scarce resource in useful frequency ranges.
The mesh model, where every rooftop is a node routing encrypted traffic to neighbors, feels much more sustainable / forward-looking to me.
There are amateur radio satellites that you can legally communicate with using a technician’s license and equipment for around $100 (essentially a UHF/VHF FM walkie-talkie and an external antenna, i.e. just analog voice).
If you have a fairly modern iPhone, you can already share your location to a satellite out of the box.
And if unidirectional communication counts, you already do it every time you use GPS :)
Most of satellites you don’t talk to, the satellite repeats signals. People talk to each other, mainly to make contacts, using the satellite.
It is also possible to talk to ISS.
1: https://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-noaa-weat...
The round-trip speed of light to a geosync orbit is 239ms, but some of these LEO sats are already sitting as close as a 4ms round-trip away, and there have been proposals for some even closer.
> Researchers in Switzerland have transmitted and received optical data at rates of more than 10 Tbit/s between an Alpine peak and an observatory at the University of Bern – a distance of 53 kilometres. This is more than five times further than would be needed to set up a satellite-to-ground communication link
Google says Starlink satellites are 550km in altitude... Is this to do with turbulence below 10km?
Would a Solar Flare wrap around the earth?
Or are Solar Flares so massive they would envelop the earth, like dunking a globe in cosmic lava?
Or do they go on long enough that the earth would rotate and all sides of the globe would be exposed?
Or do Satellites whizz around the earth fast enough that they would travel through the path of the Solar Flare?
Probably hilariously odd questions, but I have no idea! :-)
This seems to be strictly about high data rate applications and the certainly soon to be extremely goofy world of "6G."
That’s the type of service these new services are going to be providing in their first phase, just (if all goes well) with unmodified mobile devices.
I’d guess we’re some time away from broadband data to unmodified phones, but in the end, it’s just a function of available power per square meter in the downlink, i.e. how many satellites can be launched and how tightly their beams can be focused, and of reflector size in the uplink (since the transmit power of 4G/5G devices is fixed at about 1-2% that of Iridium).
Pic- https://spacenews.com/ast-spacemobile-secures-communications...
Pic from earth - https://twitter.com/tzukran/status/1731409049004982558
> For example, AST SpaceMobile’s first satellites had antennas with surface areas of 64 square meters, followed by second generation satellites with 128 m2 antennas, with plans for going up to 400 m2
I guess when the Starship rocket is available and if they have a reliable folding mechanism, this could happen. The question is probably whether they can keep the cost under control .