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SpaceX plans worldwide satellite Internet with low latency, gigabit speed

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Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#144
post #56

Earlier quoted context omitted.

To take home users as an example, the residents generally sleep 8-10 hours a day, work 9 hours a day, commute ~1 hour a day, leaving only about 6 hours of free time at home a day. Assuming they spend that entire time watching 4K Netflix (25Mbit), they'll have used ~2TB in a month, or ~6Mbit/s total. Averaging bandwidth out over the whole month, each satellite would be able to support 3800 people. With the 4400 satell…

Yeah, most people sleep at the same time. Working for a CDN, we see our POPs gets about 4x traffic at peak compared to low times.

Most people sleep at the same time in one given geography, but if you're looking at the world, those times are pretty well distributed. Assuming I'm sleeping 8 hours a day, even the continental US only has 5 hours per day when everyone is asleep when you account for time zones. But APAC, ME/Africa, and Europe are all pretty reliably awake at that time.

Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#145
post #22

Earlier quoted context omitted.

People aren't generally using a 1 gbps connection at 100% capacity 100% of the time. If we assume customers use an average of 1 TB of data per month and the time they use it is pretty spread out (seems reasonable since they are going to be spread out accross timezones eventually), you can serve about 6 million customers with 800 satelites @ 23 GBPS, and with 4400 @ 23 GBPS you could do ~33 million. Admittedly these n…

This might primarily be for their autonomous vehicles. It makes sense for them not to rely on 3rd party for cost/reliability reasons.

Heck, the leap in positioning accuracy 4.4k satellites would make gps obsolete. Civilian gps accuracy is low enough that you cannot distinguish between lanes on a highway.

Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#146
post #27

I don't know how they're going to get 25/35ms hops. If they're using low orbits to reduce latency, the surface coverage is going to be lower so they're going to have to mesh them in some way to span large areas. That means routers and intelligence which means uplink, interlink, downlink hops in both directions. 600ms here we come again.

30ms and Telstra is out of business in Australia. Finally, bring it on. Actually, give me 2000ms and a Musk plan, I'll take that over Telstra.

Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#147
post #124

Earlier quoted context omitted.

Interesting idea but wouldn't a satellite to car connection be pretty unreliable? Since the line of sight would often have things in the way. I'm assuming trees, bridges, and being in a garage would interfere with it.

I used to have a sat phone (Thuraya) and it was pretty reliable if you were outside. They don't work well inside buildings.

You'll get around that in your home by having the satellite module thing up on your roof and a cable to your wifi router.

What I don't understand about this though is the number of frequencies available to connect to all these satellites and how it might extend to ~300 million people (let alone a billion potentially).

Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#148
post #56

I don't understand the math. 800 satellites at 23 gbps seems to be able to provide 1 gbps to 18,400 connections at any given time. This seems to be many magnitudes off from what would be needed to have any impact. What am I missing?

To take home users as an example, the residents generally sleep 8-10 hours a day, work 9 hours a day, commute ~1 hour a day, leaving only about 6 hours of free time at home a day. Assuming they spend that entire time watching 4K Netflix (25Mbit), they'll have used ~2TB in a month, or ~6Mbit/s total. Averaging bandwidth out over the whole month, each satellite would be able to support 3800 people. With the 4400 satell…

But also bear in mind that the all the satellites over New Zealand (for example) will be wasted while we are asleep and at any given time a lot of satellites will be over empty ocean (sending 4K Netflix to cruise ships maybe).

I';; also counteract may own argument as to numbers with the idea that 16 million people could really mean 16 million households if they watch the movie together :-)

Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#149

Earlier quoted context omitted.

Interesting idea but wouldn't a satellite to car connection be pretty unreliable? Since the line of sight would often have things in the way. I'm assuming trees, bridges, and being in a garage would interfere with it.

Well, there's going to be 800 of the suckers. There are only about 33 GPS satellites. Although 700 miles is lowish orbit, it's still above the horizon over 2000 miles away.

Wow. I read this comment and thought, "This has to be bullshit." But lo and behold, the core satellite 'constellation' is only 24 satellites[1]. That's mega impressive.

https://www.faa.gov/about/office_org/headquarters_offices/at...

Re: SpaceX plans worldwide satellite Internet with low latency, gigabit speed

#150

And hella pingtimes ;)

> SpaceX expects its own latencies to be between 25 and 35ms Unless you're doubting their math, that's not a high ping at all. In fact, that's a pretty amazing improvement given that existing satellite internet is >500ms. I didn't realize the difference between LEO and geostationary was that high.

you are correct, this is interesting. i was mostly making a joke referring to GSO satellite internet
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