T-Mobile US and SpaceX hope to deliver phone service from space T-Mobile US and SpaceX have announced plans to use satellites in low Earth orbit to provide cellphone coverage in remote locations across the US and perhaps globally using existing devices. The two companies announced the scheme under the banner of "Coverage Above and Beyond" at an event hosted by SpaceX founder, CEO, and …
no dead zones anywhere in the world...
This is demonstrable false.
China, for example, forbids all satellite phones in their country. There are other countries that do as well, but China is by far the largest.
If the company that sends you the bill is US based, or banks in the US, then they have to abide by our sanctioned destination lists, so no Cuba, no North Korea, no Russia.
Did you even watch the presentation? I guess not
Its using 4G/5G frequency bands that T-Mobile has licensed in the US so that existing phones can receive service in dead zones - not satellite phones or related technology.
And re: 'if the bill is US based' - TMobile is only offering it to existing subscribers in the US. They want other regional carriers using the same frequency bands to sign up and sign unilateral agreements for providers to extend service to their customers when roaming. Granted SpaceX is a US based company but I suspect 'roaming service in North Korea' is a moot point.
Presentation? I read the article. Either the article was lacking or you got hooked by the marketing wanks.
The very first paragraph of the article states -
"T-Mobile US and SpaceX have announced plans to use satellites in low Earth orbit [...] and perhaps globally using existing devices." Emphasis mine.
Who cares about the frequency or protocol. If it is phone is communicating with a satellite, then it is verboten in China.
Just like if you rent an Iridium phone, it does not work in Cuba, or Russia, or Afghanistan, or North Korea or in any other sanctioned countries. Or in countries like China where such technology is forbidden by local law.
Clearly it cannot be used anywhere in the world.
I have no mobile coverage but have Starlink. My phone number is only really used as a device ID. I make phone calls and send messages using whatsapp, telegram etc and companies (DHL, paypal etc) send me messages using those. Most other codes i need come via installed apps. Only my Spanish banking app tries to send me old fashioned SMS thingies. So I'm asking myself why I need a phone signal?
Weird. Oh, Starlink dropped their service price yesterday. Down from 108€ a month to 70€.
Many thanks Mr Musk.
Long term, this is absolutely right. We don't need all these mobile/cellular protocols, just data/internet protocol. Either delivered by satellite or by a terrestrial network.
But this T-Mo/SpaceX deal is just a stopgap. It will give SpaceX/Starlink some real world experience of dealing with handsets tho, which will probably be technically useful in delivering the long term solution eventually.
I cannot see how this can possibly work as promised; my reasons for saying this:
1. Musk is involved, and we know how reliable he is!
2. Mobile phones are designed to communicate to base stations that are typically less than 30 km away (you can get further, but only in ideal weather conditions). For a LEO satellite at, say, 300 km altitude the signal is going to be attenuated by at least 3 orders of magnitude, probably more given the frequency bands involved (rain-fade is a bitch).
3. The frequencies used by mobile phones are reserved for terrestrial use only, they cannot be used for satellite up- or down-links. Any attempt to use them for that purpose is going to trigger legal action (probably by the other mobile phone networks). I personally know of at least two hybrid mobile-satellite networks that failed due to this problem.
4. Doppler is going to be a bitch to solve; mobile waveforms are design to operate in an environment of low doppler (caused by travelling a few 100 kmh). The sort of Doppler associated with a satellite is way outside of the waveform specifications.
5. Musk is involved, and we know how reliable he is!
1. agreed, probably trying to raise SpaceX share price so he can afford Twitter.
2. AST satellite mobile has a system in development. The sat is the size of a basketball court, divided roughly into 100 individual antennae, each of which is beam steerable in two dimensions. Those are much bigger antennae than your average base station.
3. No idea, but as they use mobile phones at normal power rather than sat-links at high power, I'm guessing the regulators won't have a problem in sensible countries, probably will be a problem in countries that don't like information moving freely.
4. Not when it's overhead.
I would think acquisition would be a challenge as you can't use a narrowly focused beam, so the signals will be very weak.
"I would think acquisition would be a challenge as you can't use a narrowly focused beam, so the signals will be very weak."
I would think probably the exact opposite. Unless I've botched the math (wouldn't be the first time), you probably have to use a narrowly focused beam, otherwise, you'll be trying to sort out signals from every currently active cellular phone in an area (about 1,000,000 sq km?) larger than Texas (roughly 695,000 sq km).
> I cannot see how this can possibly work as promised; my reasons for saying this:
Oh, I don't know.
All you'd need is a 4G microcell that has connects to your starlink box.
Though if you want to use your smartphone as a mobile phone, then a hat with a starlink antenna on top will be needed. As will a shopping trolley to lug around the batteries to power it all.
Simples!
Isn't the round-trip-time to the satellite also an issue? Certainly with 2G the transmissions from the mobiles are time-division-multiplexed and so have to be carefully timed so that they arrive at the base station in their correct time slots, IIRC this limits the range to about 50 miles.
You forgot:
6: T-mobile are involved and we all know what a bunch of rapacious, lying, thieving bastards they are.
Then again, they'll probably be why it does eventually happen. The prospect of being able to lock-in customers globally at whatever they want to charge must be giving them repeated orgasms.
I can see how this can possibly work. SpaceX and T-mobile both employ skilled RF engineers. Believe it or not they already anticipated problems with signal strength and Doppler shift. Licenses can be changed. There are other companies working on the same problem that do not sell Full Self Driving - to be completed real soon now.
Google tells me that Starlink satellites are about 340 miles up. From the south coast of Scotland it's sometimes possible to get a mobile connection to Manx Telecom, the nearest antennas for which are about fifty miles away. Starlink will have about 2% of that signal strength to play with. Good luck to them.
"Global coverage. As long as you're in America"
Ahem ... No. The Starlink satellites are in low circular orbits -- presumably in order to minimize latency (speed of light delays) in their populous target areas. One of the prices you pay for circular orbits is that you end up providing pretty much the same coverage to every place at the same latitude even places where there is nothing in your coverage area but a few shepards or fishing boats.
"And have a massive phone battery."
Probably not needed. The limitation on received signal strength is generally the noise floor at the receiving end. Amplification (in a receiver) is cheap and not power hungry. Most receivers intended for any serious purpose will amplify any signal stronger than ambient noise up to a usable level. FWIW, I've used my old 2G cell phone in some pretty remote locations and only found one -- a box canyon in Eastern Nevada where I couldn't raise a signal. Albeit, in the boonies, you do sometimes have to trek a few tens of meters up a hillside to find a bar or two on your phone.
--------
I wouldn't be surprised there are other problems. The cellular phone network was not designed with satellite relay in mind. But signal strength and coverage (outside of the high Arctic/Antarctic which will have zero coverage unless Elon decides to spend a lot of money to launch a bunch of satellites into polar orbits in order to serve them) probably won't be a problem.
The birds will need to rapidly steer and hand over as they pass over an active subscriber, regardless of location.
So in practice, assuming it works at all, anywhere, the issues with expanding the service to most of the rest of the world are contractual and political, not technical.
Which means they are either trivial or impossible to resolve.
At present this is a marketing announcement. We have absolutely no clue how to make it work in practice.
Yup. There's a few dependencies, like the inverse square law, clounds, and Starship actually launching. Meanwhile, in other news, that other billion dollar boondoggle will hopefully get off the ground on Monday.
It was only a decade ago SpaceX was playing around with Grasshopper & developing reusable boosters. Now those are common place.
Starlink first itched Elon's pants in 2015. And here I am only seven years later living out in the sticks and rocking 100mb/s bandwidth from a Dishy on my roof. Stick that up your backside Centurytel, after refusing to upgrade service for decades.
Cellular technology has been around since 1979 and is on its fifth generation. I have to drive eight miles to get my first bar of service. There has been plenty of time & opportunity to build cell towers in this area, but us rural folk are just not worth the investment.
Be cynical if you want, but Musk does deliver on technology a lot better than the traditional tech industry players. If he says he is going to do cellphone-to-satellite comms, it probably will happen.
How that full self driving in 2016 working out for Tesla owners? Or using their Tesla as a robotaxi to earn $100K a year he promised for 2020? Or the mind reading headband?
He's the king of making unsubstantiated promises. Just because he's delivered on some things doesn't mean he deserves the benefit of the doubt on his more wild claims considering all the broken and unfulfilled promises he leaves in his wake.
> He's the king of making unsubstantiated promises
Oh come on. The fact he’s delivered upon even some of his promises puts him ahead of many small tech businesses and a disturbing number of senior politicians.
He’s clearly a tool, but his delivery rate is higher than it should be given how crazy some of his ideas are.
The current crop of mobiles aren't built to communicate with satellites. Not even the really expensive ones. Others have correctly pointed out that the frequency bands used by mobiles are not licensed for satellite communications and power levels are limited to allow for reuse across a region. The only way I can see this working is by putting up remote cell towers to communicate with nearby phones and the tower has a ground transceiver that communicates with the satellites. The towers still have to be built and powered and the big reason those towers aren't there already is the logistics of hooking them up and the lack of customers.
As a ham, I have no problem with long distance comms when I want them. One field day I got a contact with ISS from my car set up (external antenna set up outside). When I'm in the boonies, I like to have the excuse that there is no service on my phone. It's a real zen moment when the bars finally drop to zero.
Upvoted because it's an intelligent post and correct as far as it goes.
However, Elon and his technical folk clearly know about electronically steerable phased array antennae. I have no idea what the state of the art is in phased arrays, but I know that BIG ones (football field size) can have remarkably tight beams. IF StarLink can put a sufficiently large antenna (big, but not football field size) into orbit and solve some other problems, they MIGHT be able to reduce their target area to something comparable with that of a cell phone tower. Substantial (but solvable?) problems at the satellite end? But nothing special required at the user's end. So conceptually, you really MIGHT be able to talk to an upgraded Starlink using an ordinary cell phone. ... MAYBE
FWIW, the internet assures me that many cell phones have a high power mode with 3 watt output.. Can that connect over a 300-400km link with a high gain antenna at the satellite end? My GUESS is maybe.
This is why I posted a question in these forums once as to when everyday satellite radio for in-car entertainment would exist in Europe, using LEO satellites.
If Sirius can manage it in the US with geostationary birds, this should be falling off a log stuff for Starlink. Yet the idea simply got downvoted.
Downlinks are the easy(ish) bit, it's the uplink that's going to be the real problem. Especially if it's meant to work with current 5G handsets
Exactly, you might get one sat to focus on that phone but the phone will reach many other sats, precisely why they don't like phone being use on planes - it not the plane but several dozen cell towers being in reach at once
A rural cell tower with solar panels, batteries and starlink connection might well be a lot cheaper than a "traditional" cell tower with a microwave link to the next tower and the next tower and the next tower before it finally reaches the main network. I don't think that's the plan, but it might be more viable than the traditional network of towers and infrastructure.
"A rural cell tower with solar panels, batteries and starlink connection might well be a lot cheaper than a "traditional" cell tower with a microwave link to the next tower and the next tower and the next tower before it finally reaches the main network."
Perhaps in a few places. The places that don't have coverage usually don't have customers thick enough on the ground to make sense. To maintain and service remote towers is super expensive and something the beancounters will want to nix if they can. A tower, solar panels, a battery AND an unserviceable Starlink system to deal with may be too much for a location that doesn't bring in more subscribers.
This is cool for another reason: T-Mobile is the network partner for "GoGo Internet", one of the larger providers of Internet access aboard commercial airline flights. Right now they get their signal by pointing their antennas DOWN at T-Mobile towers, but in the future they could point UP at satellites.
(This is the reason T-Mobile subscribers get a free hour of wifi aboard those flights, by the way)
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