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I'm not sure we can really say if their tech is "obviously and objectively capable" at scale. We don't really know enough about the PHY layer modulation or even

I'm not sure we can really say if their tech is "obviously and objectively capable" at scale. We don't really know enough about the PHY layer modulation or even the mac layer modulation they're using. My guess has always been that they use some flavor of OFDM, but this is a detail thats unrevealed currently. These are incredibly important details for the oversubscription calculus in the access network itself. RDOF aims to hold providers to a much higher standard for rural broadband, and part of that commitment is whether you can deliver speeds across the whole network at scale, not just relying on theoretical top line speeds. The evidence so far per Ookla demonstrates they don't meet muster currently, and since the tech is so new and (mostly) unvetted, it makes sense for the FCC to play it safe here on behalf of the consumer.

wmf 4y ago
That information is out there but it's scattered and hard to find. The real bottleneck right now seems to be that the number of beams per satellite is higher than the number of cells per satellite.
- spmurrayzzz 4y ago
  I haven't seen anything official nor convincing about the aspects I commented on. I've seen the write up on the individual who was able to spin up an SDR to receive beacons from their satellites, but that doesn't really tell you anything about how the signal is modulated.
zamadatix 4y ago
The cells are 22km and the traffic path strictly client<->satellite<->ground station at the moment. There isn't really any reasonable scaling concern until you start talking about serving densely populated areas but that's not Starlink's market nor what the RDOF targets/measures anyways and the inability to service a user in a city as well as a rural user shouldn't be reasoning to not provide funding to service those rural users. That said I don't have a problem with the funding being held until the conditions are demonstrably met instead of as funding to meet them. The latter has failed too many times with providers just pocketing money to then stop executing once they have it.
- spmurrayzzz 4y ago
  Well we have to square what you're positing with the evidence right now that in the aggregate as their network size increases, the speeds are getting substantially worse over time on average. Lots of explanations for that, but its still the current outcome. And there are definitely reasonable scaling concerns here. They're using a finite set of frequencies and the laws of physics still apply. Any concurrent transmissions are going to be impacted by both their phy layer modulation strategy, in addition to the mac layer. But we know so little about those layers currently that its hard to comment without being entirely speculative.
  - zamadatix 4y ago
    The evidence right now is as their network size increases, expands to lower latitudes, covers more than non-rural users, and allows mobile use the download speed increases and the upload speed decreases. "I haven't been given the details of their MAC and PHY" isn't reasoning to jump to conclusions about their MAC and PHY architecture being problematic for the rural use case here because of that. Yes they must obey the laws of physics but this isn't a WISP, concurrent transmissions can't just stomp on each other and find out fast enough to hide it they've had to be broken out per client in the cell from day one. Other than mentioning the MAC layer exists is there a particular concern you have about it scaling? The satellites only have 2 paths to forward things and only a small patch of cells to do it for. Scaling has been brought by putting up orders of magnitude more satellites to provide coverage at more than the dense northern coverage from the orbits, it has not been by putting a ton more clients through the satellites themselves. Is RF and framing something Starlink has had to design for? Absolutely, they do after all need these things. That doesn't mean it makes sense to jump to it as the source of any perceived issues, particularly on the basis it's something unknown.
  - deleted 4y ago
    [deleted]
xoa 4y ago
>it makes sense for the FCC to play it safe here on behalf of the consumer. Maybe it "makes sense" to those who aren't actually one of those consumers. But if "playing it safe" means "you get to stay on 56k/4-1-ADSL/viasat/hughes for another 5 years and maybe you get fiber then or maybe another administration comes along and crushes this whole thing who knows! <3" then no that's not great right? The more positive angle is that this doesn't actually slow SpaceX down at all, they aren't a public company so this doesn't mean their stock plunges immediately and shareholders demand a course change or anything like that, they're obviously committed to improvements and obviously have a fair amount of private capital to tap. So it won't necessarily slow them down much if any, at least hopefully. But it does mean all the growing capacity and improvements will go exclusively to the better off who can afford the $110/mo privately in the immediate future and that's too bad. It's more too bad as well because even with someday tens of thousands of Starlink v2.0 and intersat optical mesh and greatly increased cell density, there will still be tight density limits relatively speaking. So less well off people may find themselves effectively shut out of Starlink due to having to have waited until others move/pass away/get fiber. It might not amount to much but I'd really like to see my tax dollars helping to get them something asap on a more even ground I guess. I'd be happy to be proven wrong though and for everyone to get fiber instead! >and since the tech is so new and (mostly) unvetted Shouldn't government should have more, not less, appetite for risk of this nature? If it's risk free, the market would already be doing it. Particularly after decades of throwing billions down the crapper for "safe" and "proven" tech by "reliable, established" companies which then used it to do mergers or stock buybacks or lobbying against municipal broadband and getting laws against it enacted in much of the country and perhaps a few token deployments. I completely understand and applaud the pendulum swinging back against the decades of established monopolies trying to water down definitions of "broadband" to meaningless so they could market and suck subsidies with no capex required. But all pendulums can swing back too far in the opposite direction too, and now that rapid deployment transitional tech is possible (Starlink and WISPs) it'd be nice to see timelines factored in as well. There is value to society in someone getting 50-150 via Starlink or fixed wireless until 2028 even if fiber then makes it in and obsoletes it. And there's parts of the US I doubt see it even then honestly. Also to your sibling: >They're using a finite set of frequencies and the laws of physics still apply This is nice of you to write but would you care to crunch us the numbers on Shannon limit for the Ku-, Ka-, and E- bands (ignoring V-band since nothing for that exists for Starlink yet)? Do you actually have reason to think they're maxing out potential bandwidth right now in 12-18 GHz or 26.5-40 GHz right now vs that being a tech limitation that will be improved with better phased arrays and bigger sats like v2.0? Because it's kind of a significant amount of spectrum.

wmf 4y ago

That information is out there but it's scattered and hard to find. The real bottleneck right now seems to be that the number of beams per satellite is higher than the number of cells per satellite.

spmurrayzzz 4y ago
I haven't seen anything official nor convincing about the aspects I commented on. I've seen the write up on the individual who was able to spin up an SDR to receive beacons from their satellites, but that doesn't really tell you anything about how the signal is modulated.

zamadatix 4y ago

The cells are 22km and the traffic path strictly client<->satellite<->ground station at the moment. There isn't really any reasonable scaling concern until you start talking about serving densely populated areas but that's not Starlink's market nor what the RDOF targets/measures anyways and the inability to service a user in a city as well as a rural user shouldn't be reasoning to not provide funding to service those rural users. That said I don't have a problem with the funding being held until the conditions are demonstrably met instead of as funding to meet them. The latter has failed too many times with providers just pocketing money to then stop executing once they have it.

spmurrayzzz 4y ago
Well we have to square what you're positing with the evidence right now that in the aggregate as their network size increases, the speeds are getting substantially worse over time on average. Lots of explanations for that, but its still the current outcome. And there are definitely reasonable scaling concerns here. They're using a finite set of frequencies and the laws of physics still apply. Any concurrent transmissions are going to be impacted by both their phy layer modulation strategy, in addition to the mac layer. But we know so little about those layers currently that its hard to comment without being entirely speculative.
- zamadatix 4y ago
  The evidence right now is as their network size increases, expands to lower latitudes, covers more than non-rural users, and allows mobile use the download speed increases and the upload speed decreases. "I haven't been given the details of their MAC and PHY" isn't reasoning to jump to conclusions about their MAC and PHY architecture being problematic for the rural use case here because of that. Yes they must obey the laws of physics but this isn't a WISP, concurrent transmissions can't just stomp on each other and find out fast enough to hide it they've had to be broken out per client in the cell from day one. Other than mentioning the MAC layer exists is there a particular concern you have about it scaling? The satellites only have 2 paths to forward things and only a small patch of cells to do it for. Scaling has been brought by putting up orders of magnitude more satellites to provide coverage at more than the dense northern coverage from the orbits, it has not been by putting a ton more clients through the satellites themselves. Is RF and framing something Starlink has had to design for? Absolutely, they do after all need these things. That doesn't mean it makes sense to jump to it as the source of any perceived issues, particularly on the basis it's something unknown.
- deleted 4y ago
  [deleted]

xoa 4y ago

>it makes sense for the FCC to play it safe here on behalf of the consumer. Maybe it "makes sense" to those who aren't actually one of those consumers. But if "playing it safe" means "you get to stay on 56k/4-1-ADSL/viasat/hughes for another 5 years and maybe you get fiber then or maybe another administration comes along and crushes this whole thing who knows! <3" then no that's not great right? The more positive angle is that this doesn't actually slow SpaceX down at all, they aren't a public company so this doesn't mean their stock plunges immediately and shareholders demand a course change or anything like that, they're obviously committed to improvements and obviously have a fair amount of private capital to tap. So it won't necessarily slow them down much if any, at least hopefully. But it does mean all the growing capacity and improvements will go exclusively to the better off who can afford the $110/mo privately in the immediate future and that's too bad. It's more too bad as well because even with someday tens of thousands of Starlink v2.0 and intersat optical mesh and greatly increased cell density, there will still be tight density limits relatively speaking. So less well off people may find themselves effectively shut out of Starlink due to having to have waited until others move/pass away/get fiber. It might not amount to much but I'd really like to see my tax dollars helping to get them something asap on a more even ground I guess. I'd be happy to be proven wrong though and for everyone to get fiber instead! >and since the tech is so new and (mostly) unvetted Shouldn't government should have more, not less, appetite for risk of this nature? If it's risk free, the market would already be doing it. Particularly after decades of throwing billions down the crapper for "safe" and "proven" tech by "reliable, established" companies which then used it to do mergers or stock buybacks or lobbying against municipal broadband and getting laws against it enacted in much of the country and perhaps a few token deployments. I completely understand and applaud the pendulum swinging back against the decades of established monopolies trying to water down definitions of "broadband" to meaningless so they could market and suck subsidies with no capex required. But all pendulums can swing back too far in the opposite direction too, and now that rapid deployment transitional tech is possible (Starlink and WISPs) it'd be nice to see timelines factored in as well. There is value to society in someone getting 50-150 via Starlink or fixed wireless until 2028 even if fiber then makes it in and obsoletes it. And there's parts of the US I doubt see it even then honestly. Also to your sibling: >They're using a finite set of frequencies and the laws of physics still apply This is nice of you to write but would you care to crunch us the numbers on Shannon limit for the Ku-, Ka-, and E- bands (ignoring V-band since nothing for that exists for Starlink yet)? Do you actually have reason to think they're maxing out potential bandwidth right now in 12-18 GHz or 26.5-40 GHz right now vs that being a tech limitation that will be improved with better phased arrays and bigger sats like v2.0? Because it's kind of a significant amount of spectrum.