3 ms·

Also bandwidth. Because there is little other use for the satellites over the pacific, the instant the first phase of the constellation is up, it is better than

Also bandwidth. Because there is little other use for the satellites over the pacific, the instant the first phase of the constellation is up, it is better than the Southern Cross fiber line at everything it does.

the8472 8y ago
I'm a bit skeptical about that. Fiber has mind-boggling bandwidth scaling compared to beaming radio signals through a hundred kilometers of atmosphere. Light has a higher bandwidth and you can put more than one fiber into a cable and there's less interference too.
- Tuna-Fish 8y ago
  Their satellites don't communicate with each other by radio links, but by laser. Laser works better in vacuum than it does in fiber. Radio is just for the downlinks.(1) They have not publicly stated anything about the inter-satellite links, but a research paper published by independent researchers(2) estimated that based on other state of the art, they get >100Gbps of bandwidth between two communicating satellites. The total trans-pacific capacity between NZ and the US will be better than the SC fiber line because there will be many different non-sharing paths using different satellites. (1): Also likely for crossing connections. The paper mentioned below assumed use of laser for those too, but that is IMHO unlikely because steering would be too hard. Lasers work great for satellites on the same plane and those that are on the neighboring ones, because the angular speed that the system needs to move to track stays very low -- the satellites near them are almost stationary from their point of view. In contrast, satellites on crossing planes zip by very fast and have high angular motion, especially when near. (2): http://nrg.cs.ucl.ac.uk/mjh/starlink-draft.pdf http://nrg.cs.ucl.ac.uk/mjh/starlink-draft.pdf
  - the8472 8y ago
    The up/downlink is the bottleneck if you want to provide backbone-like connectivity over satellites, and that's still done via radio. Those speeds may be great for individual endusers, but if you're a datacenter which needs a lot of bandwidth then starlink would be limited by the shared radio bandwidth to the sats, which could be quite crowded in an urban environment, while fiber wouldn't be. That's why I only see them as competing on latency, not on bandwidth.

the8472 8y ago

I'm a bit skeptical about that. Fiber has mind-boggling bandwidth scaling compared to beaming radio signals through a hundred kilometers of atmosphere. Light has a higher bandwidth and you can put more than one fiber into a cable and there's less interference too.

Tuna-Fish 8y ago
Their satellites don't communicate with each other by radio links, but by laser. Laser works better in vacuum than it does in fiber. Radio is just for the downlinks.(1) They have not publicly stated anything about the inter-satellite links, but a research paper published by independent researchers(2) estimated that based on other state of the art, they get >100Gbps of bandwidth between two communicating satellites. The total trans-pacific capacity between NZ and the US will be better than the SC fiber line because there will be many different non-sharing paths using different satellites. (1): Also likely for crossing connections. The paper mentioned below assumed use of laser for those too, but that is IMHO unlikely because steering would be too hard. Lasers work great for satellites on the same plane and those that are on the neighboring ones, because the angular speed that the system needs to move to track stays very low -- the satellites near them are almost stationary from their point of view. In contrast, satellites on crossing planes zip by very fast and have high angular motion, especially when near. (2): http://nrg.cs.ucl.ac.uk/mjh/starlink-draft.pdf http://nrg.cs.ucl.ac.uk/mjh/starlink-draft.pdf
- the8472 8y ago
  The up/downlink is the bottleneck if you want to provide backbone-like connectivity over satellites, and that's still done via radio. Those speeds may be great for individual endusers, but if you're a datacenter which needs a lot of bandwidth then starlink would be limited by the shared radio bandwidth to the sats, which could be quite crowded in an urban environment, while fiber wouldn't be. That's why I only see them as competing on latency, not on bandwidth.