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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

#331

Post by [deleted] »

sbierwagen wrote: post #319
assttoasstmgr wrote: post #297

Earlier quoted context omitted.

Yeah that's not how it works. You can't just "put the complicated antenna on the satellite, instead of on the phone" and declare this problem solved. If you believe that I have a bridge to sell you. I'm declaring shenanigans right now on Elon's pitch but what else is new. It makes me sad that this thread is full of (probably) SWEs in a complete froth who took this at face value with little understanding of how antenn…

>"circular polarization" to combat things like the Faraday effect Another factor is that the antenna on a satellite can be in a pretty arbitrary rotation compared to the receiver on the ground. Circular polarization doesn't care about orientation. Further discussion here: https://ham.stackexchange.com/questions/12414/antenna-polari... >Satellite phones and communicators are designed to direct most of the energy upwar…

[deleted]

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

#332

Post by bagels »

dailykoder wrote: post #288
vlovich123 wrote: post #276

Earlier quoted context omitted.

Let me clarify. Musk claimed 6 years ago [1] that shipping Teslas would be capable of Level 5 autonomy. While Tesla’s markets their feature as “full self driving” it’s a far cry from even level 3 afaik. It’s kind of sad people fall for this. It also has lethal consequences as people assume it can do things it very well can’t (cruise control+ is really what the feature is). It’s a very obvious grift and SEC and FTC re…

Musk already admitted that he was very wrong about FSD and that it's not that easy. Sure his talk was dumb and a lot of people fell for it, but that's just how marketing works.

That's how fraud works, not marketing.

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

#333

Post by throwawaylinux »

vlovich123 wrote: post #276
thepasswordis wrote: post #259

Earlier quoted context omitted.

My current Tesla started doing FSD almost a year ago.

Let me clarify. Musk claimed 6 years ago [1] that shipping Teslas would be capable of Level 5 autonomy. While Tesla’s markets their feature as “full self driving” it’s a far cry from even level 3 afaik. It’s kind of sad people fall for this. It also has lethal consequences as people assume it can do things it very well can’t (cruise control+ is really what the feature is). It’s a very obvious grift and SEC and FTC re…

Yep, if there's one thing that the AI "community" has done, it's over promise and under deliver. Tesla was a lot more fortunate than some others, being an automotive company first, and an AI company at best 4th (after battery, charging network).

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

#334

Post by fsh »

intrepidhero wrote: post #218
kibibyte wrote: post #143

Earlier quoted context omitted.

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?

There are cell phone sized thingies that can send text messages to iridium's constellation, which is (as I understand it) way further away than starlink. I use one while backpacking. I'd be super excited to get the same capability in a standard cell phone.

The Iridium orbit heights are not much higher (781 km vs. 550 km). You can always trade bandwidth for increased sensitivity. The most extreme example is GPS. Your phone can receive it from 20000 km away with a tiny antenna, but the data rate is only 50 bits per second.

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

#336

Post by assttoasstmgr »

mhio wrote: post #330
assttoasstmgr wrote: post #297

Earlier quoted context omitted.

Yeah that's not how it works. You can't just "put the complicated antenna on the satellite, instead of on the phone" and declare this problem solved. If you believe that I have a bridge to sell you. I'm declaring shenanigans right now on Elon's pitch but what else is new. It makes me sad that this thread is full of (probably) SWEs in a complete froth who took this at face value with little understanding of how antenn…

This isn't a Starlink/SpaceX scheme. Non-terrestrial networks are being worked into the 3GPP specifications and highlight the same handset difficulties that need to be addressed. It's not the phone currently in your pocket that does this but might be fine on the phone you get in the next few years. https://www.3gpp.org/news-events/partners-news/2254-ntn_rel1... The BlueWalker 3 test satellite from AST should launch i…

> It's not the phone currently in your pocket that does this but might be fine on the phone you get in the next few years.

I don't think anyone's questioning this - yet there's people here rage-posting the ludicrous assertion that the very handset in your pocket right now will work with Starlink unmodified. This is what I have an issue with. More FSD-style overpromising and underdelivering all over again.

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

#337

Post by ahefner »

dvdkhlng wrote: post #326
danellis wrote: post #280

Earlier quoted context omitted.

Interesting. Is there no distance limit? I don't know how 5G works, but in 2G there was a limit of about 30km, since that's as much as the timing advance would allow for (sending the signal early so that it arrives in its timeslot despite the speed-of-light delay).

I'd think that the distance limit for _terrestrial_ mobile networks comes from the guard interval of the OFDM modulation [1]. I.e. on longer distances the time-offset between different different reception paths (due to reflections) of the signal becomes so long that you cannot compensate those with just a complex gain-factor of the OFDM vectors. AFAIR LTE (4G) even uses different guard intervals depending on rural vs…

Nitpick: You probably mean DVB-S (and S2, S2X..) rather than DVB-C, and you're correct that they don't employ OFDM (they're just a straightforward single wideband channel mostly employing variations on phase-shift keying), and aren't particularly concerned with multipath interference.

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

#338

Post by LeoPanthera »

simonebrunozzi wrote: post #335

I bet that Musk's next company will be a mobile carrier. It will disrupt the industry, like he did with cars.

You can't just magically become a mobile carrier. You need spectrum. The only practical way to do it is to buy an existing one.

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

#339

Post by Roark66 »

This is indeed very nice if it is implemented. As for T-mobile, how about they commit to ipv6 on all of their LTE networks? Here in Poland they have a network sharing agreement with Orange which means they use the same infrastructure, but when I use Orange's APN I get an ipv6 address. With T-mobile only ipv4 and they have no plans to implement ipv6.

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

#340

Post by mr_toad »

ericabiz wrote: post #153

I believe this is SpaceX trying to stay one step ahead of Apple. Anyone else remember this strange rumor about iPhones including satellite capability a year ago? https://www.macrumors.com/2021/08/29/iphone-13-to-feature-le... Now you have Apple’s event in a couple weeks themed “Far Out” with space pictures. I wouldn’t be surprised at all if Apple announced something similar, possibly with Globalstar instead. Of cours…

> Of course, Apple’s solution will likely only work with iMessage.

If I’m in the middle of nowhere and need to send an urgent message I wouldn’t want to be worrying about whether the recipient had an Android phone.

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