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SpaceX, T-Mobile to connect satellites to cellphones in remote areas

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Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#141

I watched the announcement. Knowing Musk, I'll believe it when I see it, but it sounds promising. Apparently the G2 Starlink satellites will be equipped with large antennas to support cellular users on the existing spectrum. Video was live-streamed, and still available here: https://www.youtube.com/watch?v=Qzli-Ww26Qs

Curious that the Apple event next month is themed "Far Out" with space imagery. I imagine this is the modems that were widely reported last year as being part of the 13/14 SOCs I think this is very interesting and a smart move for Starlink to improve profitability options in the long term.

The rule of thumb for Apple Event invitation themes is to just assume they mean nothing—or that they’re just screwing around with people who like to read them like tea leaves.

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#142

AST SpaceMobile will be launching its first cellular base station satellite on a Falcon rocket later this year. https://ast-science.com/

How exactly does that work? Cell phones have such small antennas and put out a relatively weak (and omnidirectional) signal. I think the phone would have trouble receiving the satellite's transmissions and vice versa.

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#143

Earlier quoted context omitted.

What the... is that what's possible with 5G? Amazing, and even days ago I was thinking of satellite smartphone internet as something scifi because of (clearly incorrect!) complicated antenna requirements.

4G/LTE was commonly quoted as 3km range for rural installations (using the 2GHz bands). 5G added 700MHz and 800MHz bands that are quoted as 10-20km achievable range. For typical cell tower heights 20km is about the range where they would sink behind the horizon, so that might be the practical limit here. Starlink satellites are about 330km up, so one order of magnitude further. But they also have basically unobstruct…

GPS is a thing, so I can imagine that a phone would be able to receive satellite signals pretty easily. But for transmission, I can't imagine this working without having your phone put a ton of power into sending a powerful enough signal, perhaps more so than how much power you need to passively receive GPS signals in the absence of traditional cell towers?

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#144

Earlier quoted context omitted.

No, it's the latter of what you mentioned-- direct cell to SpaceX satellites

I thought existing Starlink needed a phased array antenna to get decent signal strength. How the hell is a cell phone radio going to reach a satellite?

If they're just going to be using this for sending texts for now, the signal to noise ratio can be really bad and still work. I suppose they could also fall back on buffering until a satellite is in an optimal position if it can't send immediately -- texts should arrive quickly, but they don't have to be quite real-time.

That's my guess anyways, there might be some other tricks involved and it's an impressive thing to do at any rate.

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#146
post #44

Anecdotally, 5G is significantly better at line of sight at significant distances than previous technology. While sailing 40+ miles offshore this summer, I've gotten 5G on deck, with decent upload performance using my iPhone, when in years previous I didn't get coverage much beyond 12 miles anywhere around where I sail, despite there being tall buildings with cell towers on them with a 30+ mile horizon for at least 2…

Not sure what would make 5G any better than LTE for coverage, maybe your towers were simply upgraded to higher power during a 5G upgrade?

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#147
post #44

Anecdotally, 5G is significantly better at line of sight at significant distances than previous technology. While sailing 40+ miles offshore this summer, I've gotten 5G on deck, with decent upload performance using my iPhone, when in years previous I didn't get coverage much beyond 12 miles anywhere around where I sail, despite there being tall buildings with cell towers on them with a 30+ mile horizon for at least 2…

I’m booking a cruise on which they’re asking $200 for five days of data. This would be helpful if we were too far off shore to get reception to avoid such high fees. Starlink itself currently offers service to ships at a cost of $5000/mo. plus $10,000 for the hardware. This could save a lot of money where a simple mobile data plan would suffice.

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#148

How will this work in terms of spectrum usage across countries? Will every country have to allocate the same frequencies as the carriers involved in the US? Will every phone have to support particular bands used in the US? A bit confused about how they anticipate tackling the hurdles here.

I imagine that the satellites can switch frequencies within a small margin as they commonly need to do that when faced with interference. They can already shut off when traveling over countries where they don't have broadcast permission. But yes, it seems like ~2GHz is what SpaceX/T-Mobile is using here, so they'd need approval around those frequencies or more antennas on the satellites for higher frequencies which doesn't make alot of economic sense. Also the penetration will get worse the higher in frequency they go.

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#149

Earlier quoted context omitted.

Self-driving cars have proven harder than expected, but given the rest of Musk's tale, I wouldn't bet against him. SpaceX is already launching satellites, and Starlink is already providing service. T-mobile owns the frequencies for it, it's "just" a matter of building the satellites and putting them into space. If the claim were more outlandish, it would be harder to buy, but the technology is eminently doable.

Just a couple days ago they announced that they will also be using Falcon 9 to launch the new Gen2 Starlink satellites, instead of the original plan to launch all of them using the still-in-development Starship. So it seems like Musk is pretty committed to doing this in a reasonable timeline, with smaller technology risk.

Starship's orbital test may happen somewhere in the next 6 months, so until they succeed with that Falcon 9 is all they have (it's plenty though).

Re: SpaceX, T-Mobile to connect satellites to cellphones in remote areas

#150
Color me not the least impressed.

I pay $200/month for my family to use T-Mobile. Data barely works in my backyard--and I'm one city over from their headquarters. I've called them and I've Tweeted. They energetically tell me they're taking action and... nothing happens.

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