5 ms·
Wow, I'm impressed! I thought it would take more than a decade to implement when it was announced, but it's here and it works. Just amazing. 100/16 Mbps is pre
by bserge 6y ago
Wow, I'm impressed! I thought it would take more than a decade to implement when it was announced, but it's here and it works. Just amazing.
100/16 Mbps is pretty decent I guess, hopefully it doesn't go down as the number of users goes up. The latency is great imo, 40ms using satellites? I don't think anyone has achieved that before.
Would a bigger dish work better or not?
- Gwypaas 6y agoAiming for 20 ms later this year. (Elon time) A bigger dish would not lower latency but may increase signal strength leading to better throughput. But it's not a simple parabolic antenna. It is the first consumer oriented phased array antenna tracking the satellites as they move across the sky, so that would increase the antenna cost even more. https://en.wikipedia.org/wiki/Phased_array https://en.wikipedia.org/wiki/Phased_array
- Reventlov 6y ago« A bigger dish would not lower latency but may increase signal strength leading to better throughput. » A better signal strength would probably lead to better modulations being used, therefore, less transmission and reception time, and a better latency, or am I wrong ? (at least that's the case for Wi-Fi: the better the signal strength, the lower the transmission time so the better the latency).
- swiley 6y agoIt could also mean less retransmission, depending on how the MAC works. That would lower the average latency.
- labcomputer 6y agoLatency in this case is dominated by time-of-flight to the satellite. At 100 Mbps with a 40 ms latency, there are about 2 megabits in the air between the ground station and CPE.
- Denvercoder9 6y ago> Latency in this case is dominated by time-of-flight to the satellite. Is it though? Starlink orbits at 550 km, time-of-flight from ground to satellite to ground would be only 3.7ms, twice that makes ~20% of the roundtrip latency.
- Robotbeat 6y ago550km is the closest approach. Usually it will be at least sqrt(2) times that (ie at least a slant angle of 45 degrees), maybe 2 times that. Plus the latency from the Gateway to the actual server. And the Gateways can have even greater slant angle to the satellite than the mobile terminals.
- Denvercoder9 6y agoI don't think it'll usually be at a slant angle of at least 45°. The beta requires a field of view of 100° after tilting. I can't find the maximum tilt angle, but SpaceX has authorization to transmit only 25° degrees above the horizon, so the maximum slant angle is 65°.
- Robotbeat 6y agoBut think what that means in terms of SOLID angle, not linear angle.
- Denvercoder9 6y agoOrbital planes are so close together that it doesn't make much difference. However, now that I've actually calculated it, your sqrt(2) factor seems to be about right for the average distance -- there's too few satellites per plane in the current phase. In this phase Starlink uses 72 orbital planes, with 22 satellites per plane, so 1440 satellites in total (they're almost there). It orbits at 550km above Earth's surface, so the orbit has radius 6921km, which gives an orbital length of 43486km. Separation between orbital planes varies depending on your latitude, but assume the worst case, where it is 43486km / 72 / 2 = 302km¹. Thus, the nearest orbital plane is at most 302km / 2 = 151km away from the orbital plane directly overhead. However, since the planes process, on average the nearest orbital plane is only half that, or 76km away from the plane overhead. Satellites within each plane have a separation of 43486km / 22 = 1976km. Thus, there's always a satellite at most 1976km / 2 = 988km away¹ from any point in each orbital plane, and on average there's a satellite half that away, or 494km. Adding all this together, the nearest satellite is on average √(550^2 + 76^2 + 494^2) = 743 km away (at the worst latitude). [EDIT: Actually, that's improper averaging, the correct average is obtained with ∫√(550^2 + x^2 + y^2) dx dy / ∫ dx dy on x=0..151, y=0..988, which yields 777km]. The original plan used 24 planes with 66 satellites, which reduces average distance to 617km. At more favorable latitudes the difference with the current design would be even larger. [EDIT: This should be 635km.] ¹ This is distance on the surface of the orbital sphere, straight-line distance is a bit less. It probably doesn't make much difference.
- deleted 6y ago[deleted]
- BurningFrog 6y agoI read that as "future versions of the antenna will be much improved", in price and performance. I know Moore's Law is being repealed, but that's still how new types of electronics work, right?
- kube-system 6y agoMoore’s law was specific to the way IC manufacturing worked. While it does (/did?) help reduce the price of electronic simply because they relied on ICs, the big price decreases you see in products after their early-adopter phase are likely just general economies of scale. Making small early batches of anything is more expensive per unit than making a ton of them —- regardless of whether it’s cutting edge tech or a plastic chair.
- geerlingguy 6y agoI think in the antenna's case, the primary goal would be to reduce costs for now (while still maintaining reliability), since the things currently cost $1500 per unit to make (SpaceX takes a loss on each new customer initially, for now).
- walrus01 6y agoI have seen as low at 15.85 ms from my starlink terminal to downtown Seattle. On average it's more like 22-23 ms.
- daniellarusso 6y agoSo, could multiple single units be coupled together? I assume that would be less expensive than creating larger circuit boards, shipping and packaging.
- gameswithgo 6y agoThe latency may well be better than landlines in some cases. For instance, data from an edge cache in your city will be faster than starlink. But data from china? Starlink may win. I wonder if it could improve gaming/video conferencing with people far away.
- Denvercoder9 6y agoRight now, that's not really the case though, as the satellite interlinks aren't operational yet. All your traffic goes through a base station relatively close to you, and continues over "regular" fiber around the world.
- tyingq 6y agoThis article and accompanying videos are interesting in that regard: https://www.circleid.com/posts/20191230_starlink_simulation_low_latency_without_intersatellite_laser_links/ https://www.circleid.com/posts/20191230_starlink_simulation_... It suggests they could be lower latency than a great-circle path ground fiber without the satellite interlinks.
- deleted 6y ago[deleted]
- geerlingguy 6y agoI know my Spectrum cable connection gets high 30s range for latency. Starlink is close at low 40s, and as they get more sats up, that latency average may go down.
- zikduruqe 6y ago> 40ms using satellites? Starlink sats are low earth orbiting (about 250 miles away). The really high latency sats that people used to use were geosynchronous sats that are parked about 30,000 miles away, and the round trip delay between earth, bird, earth.
- house9-2 6y ago> 100/16 Mbps is pretty decent I guess Its fantastic, can't wait until this is available where I live. Currently paying $200+ a month for 20Mbps from local wireless company. 2 miles North from here there is AT&T fiber and Comcast available, 5 miles South there is Comcast (150Mbps) but I'm in a small community of homes where only options are satellite or fixed wireless.
- Scoundreller 6y agoMake friends with someone on fibre 2mi away with an old TV tower or at the top of a hill. Set up your own link.
- sillyquiet 6y agoThis seems weirdly specific and not terribly practical advice
- Scoundreller 6y agohow so?
- sillyquiet 6y agoFind an old tower? c'mon
- m4rtink 6y agoYeah, that's how we got most of our Internet access here in Czech Republic, starting ~2005. The monopolistic telecom company was totally incompetent so people banded together, bough some upstream connectivity and the connected themselves to that link via wireless point to point links using commodity WiFi hardware with directional antennas. Since them most of these networks are still in place, now in the 100 mbit/gbit territory. And while most turned into commercial volcanoes over time, there are still some that work as community organizations to this day.
- esaym 6y ago> I thought it would take more than a decade to implement when it was announced, The idea of low orbit satellites for internet has been around at least since the late 1990's [0] [0]:https://tinyurl.com/9frjxbhz https://tinyurl.com/9frjxbhz