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I suppose they need to piggyback on each mobile operator's licensed frequency bands, per country/region.

by tpmx 3y ago

Scoundreller 3y ago
Looking forward to a future Starlink+Apple/Google collab. Dunno what frequency this is running at, but if it’s in the 10s of GHz, I’m assuming licensing doesn’t get tooooo pricey given how problematic it is on land-to-land links.
- tpmx 3y ago
  Apple/Google don't hold any RF spectrum rights worldwide... This is presumably about 4G/LTE, so mostly between 0.4-2.5 GHz or so. https://en.wikipedia.org/wiki/LTE_frequency_bands https://en.wikipedia.org/wiki/LTE_frequency_bands
  - Scoundreller 3y ago
    > Apple/Google don't hold any RF spectrum rights worldwide... yet. Apple (and android baseband suppliers, “Google” may be the wrong name to mention here), have the ability to take relatively worthless spectrum and make it widely useful in a way nobody else can. I wonder how spectrum allocation works for C-Band satellite broadcasters that just blast continents with their signals. Grandfathered?
    - tpmx 3y ago
      Those several-GHz bands don't really work indoors.
      - Scoundreller 3y ago
        Most satellite-y things don’t and Starlink’s direct to cell won’t either. Hence why the spectrum should be pretty cheap (along with its incredible susceptibility to obstructions… which is less of an issue when you’re going roughly “up” without pesky considerations like curvature of the earth) And you do get a ton of gain with a small antenna at those high frequencies.
        tpmx 3y ago
        > and Starlink’s direct to cell won’t either I could see it kinda working, at low frequencies. They are not that far away and there's not many things blocking the signal besides your roof.
        Scoundreller 3y ago
        Me too, but at slower data rates. At 550km above, that’s still a big signal loss by inverse square law. Problem with slow data rates is that they clog up the channels.
        tpmx 3y ago
        The inverse square law effect can be remedied using similar tech as in the Starlink consumer antennas. You aim the signal to where it's consumed. > Problem with slow data rates is that they clog up the channels. Yes, we must protect the tubes! :)
        Scoundreller 3y ago
        Phased arrays work without having to repoint, but they don't overcome lack of incidence (insolation?) (e.g. we can't build a solar panel that works perpendicular to the sun (or nearly perpendicular) using phased array technology because there just isn't much solar radiation hitting the "dish" in the first place)
  - lxgr 3y ago
    I wouldn't be surprised if Apple were to end up buying Globalstar, which would get them access to valuable globally available L-band spectrum. They have already invested hundreds of millions into Globalstar's ground station hardware [1] and future satellite launches [2]. [1] https://www.apple.com/newsroom/2022/11/emergency-sos-via-satellite-made-possible-by-450m-apple-investment/ https://www.apple.com/newsroom/2022/11/emergency-sos-via-sat... [2] https://spacenews.com/apple-loans-globalstar-252-million-for-satellite-enabled-iphones/ https://spacenews.com/apple-loans-globalstar-252-million-for...
- Reason077 3y ago
  It works with existing 4G/LTE phones, so it will be using the standard 4G/LTE bands, which run up to 2.6 Ghz. Presumably that's why SpaceX needs to ride on existing mobile operators: they already own LTE spectrum and can allocate a chunk of it for satellite services. It would be a lot of work (and cost) for SpaceX to go out and buy LTE spectrum in every country they want to operate in.
  - usrusr 3y ago
    Sacrificing a chunk of that precious spectrum is huge though. Is LTE flexible enough to run some form of on-demand TDM between multiple base stations on top of it? Can it operate smaller cells on the same channels within the range of the larger cell, forcing the smaller cell to make do with other parts of the spectrum while the larger calls dibs? Afaik older cellular protocols were relying on zero overlap between base stations serving the same frequencies, leading to a nice coloring problem that would seriously suffer if someone tried to fit in LEO cells.
    - Reason077 3y ago
      I'm no LTE expert, but I'm pretty sure that it handles overlap: you can run LTE diagnostic apps on Android that will display all the visible base stations - often many are visible, sometimes 3 or more on the same band. Your phone looks at what's available and picks a combination with the best signal strength (sometimes it will connect on 2 or 3 different bands simultaneously with carrier aggregation). But even then, most carriers have many bands/channels (EARFCNs) available - and presumably only a small slice of bandwidth is needed for this service considering it's (initially) only for text messages. Finding 5 Mhz on one of the higher LTE frequencies wouldn't be so hard for many carriers, even if it does need an exclusive channel.
    - TorKlingberg 3y ago
      TDM seems difficult with the long time delays to satellites, but maybe. LTE is pretty flexible and can use bands as small as 1.4 MHz. It was only 1G and 2G (GSM) that needed to avoid overlap.
- inemesitaffia 3y ago
  SpaceX has applied to test the service at an Apple office
- dotnet00 3y ago
  SpaceX already works with Google, where Google allows Starlink to use its datacenters' network connectivity for downlink, while Google gets to use Starlink for data transfer.
vikarti 3y ago
There's other potential advantage (or disadvantage depending on how you view it). Some countries like India don't like sat phones on their territory. Some countries like Russia are ok with them but require local connection to terrestial networks and local licenses. Some countries are in territorial disputes. What if SpaceX or other such company decide (or would be "gently asked to") it could ignore local regulations in such country? What if it would be done for good? Possible example: somebody lobbies ITU(via some kind of "emergency license for humanitarian purposes only") to allow SpaceX to allow SpaceX to serve Gaza for free with limits and USA is ok with it. Israel is against it but what they could do? Jam Starlink? What if they also use it? What if 10 years in future same thing is done to North Korea(it could be even more legal - as far as I understood, both Koreas claims they are only legitimate goverment of Korea so SK could issue formal license)?

I suppose they need to piggyback on each mobile operator's licensed frequency bands, per country/region.

by tpmx 3y ago

I suppose they need to piggyback on each mobile operator's licensed frequency bands, per country/region.

Looking forward to a future Starlink+Apple/Google collab. Dunno what frequency this is running at, but if it’s in the 10s of GHz, I’m assuming licensing doesn’t get tooooo pricey given how problematic it is on land-to-land links.

tpmx 3y ago
Apple/Google don't hold any RF spectrum rights worldwide... This is presumably about 4G/LTE, so mostly between 0.4-2.5 GHz or so. https://en.wikipedia.org/wiki/LTE_frequency_bands https://en.wikipedia.org/wiki/LTE_frequency_bands
- Scoundreller 3y ago
  > Apple/Google don't hold any RF spectrum rights worldwide... yet. Apple (and android baseband suppliers, “Google” may be the wrong name to mention here), have the ability to take relatively worthless spectrum and make it widely useful in a way nobody else can. I wonder how spectrum allocation works for C-Band satellite broadcasters that just blast continents with their signals. Grandfathered?
  - tpmx 3y ago
    Those several-GHz bands don't really work indoors.
    - Scoundreller 3y ago
      Most satellite-y things don’t and Starlink’s direct to cell won’t either. Hence why the spectrum should be pretty cheap (along with its incredible susceptibility to obstructions… which is less of an issue when you’re going roughly “up” without pesky considerations like curvature of the earth) And you do get a ton of gain with a small antenna at those high frequencies.
      - tpmx 3y ago
        > and Starlink’s direct to cell won’t either I could see it kinda working, at low frequencies. They are not that far away and there's not many things blocking the signal besides your roof.
        Scoundreller 3y ago
        Me too, but at slower data rates. At 550km above, that’s still a big signal loss by inverse square law. Problem with slow data rates is that they clog up the channels.
        tpmx 3y ago
        The inverse square law effect can be remedied using similar tech as in the Starlink consumer antennas. You aim the signal to where it's consumed. > Problem with slow data rates is that they clog up the channels. Yes, we must protect the tubes! :)
        Scoundreller 3y ago
        Phased arrays work without having to repoint, but they don't overcome lack of incidence (insolation?) (e.g. we can't build a solar panel that works perpendicular to the sun (or nearly perpendicular) using phased array technology because there just isn't much solar radiation hitting the "dish" in the first place)
- lxgr 3y ago
  I wouldn't be surprised if Apple were to end up buying Globalstar, which would get them access to valuable globally available L-band spectrum. They have already invested hundreds of millions into Globalstar's ground station hardware [1] and future satellite launches [2]. [1] https://www.apple.com/newsroom/2022/11/emergency-sos-via-satellite-made-possible-by-450m-apple-investment/ https://www.apple.com/newsroom/2022/11/emergency-sos-via-sat... [2] https://spacenews.com/apple-loans-globalstar-252-million-for-satellite-enabled-iphones/ https://spacenews.com/apple-loans-globalstar-252-million-for...
Reason077 3y ago
It works with existing 4G/LTE phones, so it will be using the standard 4G/LTE bands, which run up to 2.6 Ghz. Presumably that's why SpaceX needs to ride on existing mobile operators: they already own LTE spectrum and can allocate a chunk of it for satellite services. It would be a lot of work (and cost) for SpaceX to go out and buy LTE spectrum in every country they want to operate in.
- usrusr 3y ago
  Sacrificing a chunk of that precious spectrum is huge though. Is LTE flexible enough to run some form of on-demand TDM between multiple base stations on top of it? Can it operate smaller cells on the same channels within the range of the larger cell, forcing the smaller cell to make do with other parts of the spectrum while the larger calls dibs? Afaik older cellular protocols were relying on zero overlap between base stations serving the same frequencies, leading to a nice coloring problem that would seriously suffer if someone tried to fit in LEO cells.
  - Reason077 3y ago
    I'm no LTE expert, but I'm pretty sure that it handles overlap: you can run LTE diagnostic apps on Android that will display all the visible base stations - often many are visible, sometimes 3 or more on the same band. Your phone looks at what's available and picks a combination with the best signal strength (sometimes it will connect on 2 or 3 different bands simultaneously with carrier aggregation). But even then, most carriers have many bands/channels (EARFCNs) available - and presumably only a small slice of bandwidth is needed for this service considering it's (initially) only for text messages. Finding 5 Mhz on one of the higher LTE frequencies wouldn't be so hard for many carriers, even if it does need an exclusive channel.
  - TorKlingberg 3y ago
    TDM seems difficult with the long time delays to satellites, but maybe. LTE is pretty flexible and can use bands as small as 1.4 MHz. It was only 1G and 2G (GSM) that needed to avoid overlap.
inemesitaffia 3y ago
SpaceX has applied to test the service at an Apple office
dotnet00 3y ago
SpaceX already works with Google, where Google allows Starlink to use its datacenters' network connectivity for downlink, while Google gets to use Starlink for data transfer.

vikarti 3y ago

There's other potential advantage (or disadvantage depending on how you view it). Some countries like India don't like sat phones on their territory. Some countries like Russia are ok with them but require local connection to terrestial networks and local licenses. Some countries are in territorial disputes. What if SpaceX or other such company decide (or would be "gently asked to") it could ignore local regulations in such country? What if it would be done for good? Possible example: somebody lobbies ITU(via some kind of "emergency license for humanitarian purposes only") to allow SpaceX to allow SpaceX to serve Gaza for free with limits and USA is ok with it. Israel is against it but what they could do? Jam Starlink? What if they also use it? What if 10 years in future same thing is done to North Korea(it could be even more legal - as far as I understood, both Koreas claims they are only legitimate goverment of Korea so SK could issue formal license)?