Can you help me understand the fundamental limitations?
I remember people saying that about cell phone networks but clever engineering has meant more and more capacity (and bandwidth) in spite of the laws of nature.
I remember people saying that about cell phone networks but clever engineering has meant more and more capacity (and bandwidth) in spite of the laws of nature.
SpaceX is pushing hard to address this - they'll probably end up launching ~135 times this year, and are aiming for more than 180 times next year[2], most of which will be Starlink. But no matter how many satellites are in orbit, there just won't be the bandwidth to service dense urban areas.
The reason that cell phones work is because there are so many cell towers. And, those towers have a density that correlates with demand.
The problem with LEO satellites is, they have to evenly cover the Earth[1]. Which means that a level of service sufficient for a dense urban area would mean that rest of the world would be ridiculously over provisioned.
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1. It's more complicated than that. Specifically, providers can use inclination to limit orbits to mid latitudes. But that only helps so much.
2. These numbers may not mean much to you, but they are absurd compared to pre-SpaceX years. SpaceX is doing more launches in a year than most rockets do in their entire lifetimes. A normal year for a SpaceX competitor like ULA is 4-10 launches, although those companies are also aiming to ramp up as Starlink competitors like Kuiper demand more launch volume.
So if you have 200 people using one satellite that’s no problem. 800 people using that whole cluster of visible satellites is also no problem. With 8000 simultaneous users you’re all down to 10 Mbps which is starting to get a bit limiting.
Each satellite covers an area about 15 miles across. About 100 square miles.
So… that works out to… something like 100 simultaneous users per square mile max.
That’s all back of the napkin math obviously… 1000 users packed into a small city surrounded by corn fields would be fine. 1000 users around every subway stop in NYC wouldn’t work even if the density is the same.
Extremely limiting given that streaming services are increasingly moving towards timed releases of shows/movies e.g. Silo is released on a Friday.
So a popular show could wipe out all capacity with enough people continuously caching a 4k stream.
I wonder how hard it would be to add multicast capabilities to Starlink? Receivers could even cache popular content on a client side disk the way e.g. US satellite TV operators do for local ad insertion.
There was a short conceptual revival of the multicast idea as an overlay network on top of unicast IP, under the banner of "content-addressable networks", but I haven't heard anything about that in a while.