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Re: 5G roadblock: labor


From: Michael Thomas <mike () mtcc com>
Date: Mon, 6 Jan 2020 15:04:23 -0800


On 1/6/20 2:42 PM, Sabri Berisha wrote:
----- On Jan 6, 2020, at 1:44 PM, Michael Thomas mike () mtcc com wrote:

Hi,

On 1/6/20 1:21 PM, Sabri Berisha wrote:
Low Earth Orbit satellites do not have a fixed position and move in a low
orbit.
But at what cost to latency? Sounds like gamers would probably hate it.
Oneweb claims 32ms average. 
https://arstechnica.com/information-technology/2019/07/onewebs-low-earth-satellites-hit-400mbps-and-32ms-latency-in-new-test/

This is one of the main advantages of LEO over geostationary. LEO is around
1,200 miles above the earth, GEO is around 22,000 miles above the earth. That's
a big difference in latency. Remember that radio travels at the speed of light.

That translates to ~118ms for GEO, and 6.4ms for LEO (one way trip). That means
that the round-trip latency without any transponder latency equals 12.8ms
for a low earth orbit signal, compared to 236ms for a GEO signal. Big difference.

This is a good read perhaps: https://www.iridium.com/blog/2018/09/11/satellites-101-leo-vs-geo/


Yeah, I know the difference. GEO sucks mightily. But doesn't this have a lot to do with what your closest base station is, or is that insignificant in the face of 2400 miles up and down?  I just checked with my provider and it's about 20ms first hop, which seems pretty high to me.

And I wonder about jitter too since it's moving and handing off.

Mike


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