Slashdot Mirror
The Mobile Internet You'll Be Using In 10 Years
mr sanjeev writes "After being plagued with project overruns and a scaling back of the final system, the US military's next-generation satellite communications network is another step closer to reality, with completion of the payload module for the third and final Advanced Extremely High Frequency (EHF) satellite ... If GPS and remote imaging (think Google Earth) have proven anything, it is that technology initially developed for military purposes, and extremely expensive for initial civil use, will eventually reach the point where it forms part of our daily lives without us ever being conscious of the massive investment to get to that point."
More important, how's the latency? The RTT to a satellite in geosynchronous orbit is pretty high (especially considering that when requesting data, you have to double the RTT vs. streaming). The article doesn't seem to say if this is high-, low-, or medium-earth orbit.
Low earth orbit can get you RTT to the satellite of ~13 milliseconds at 2000 km, adding ~26 ms to the average page load, whereas a geosynchronous orbit could take ~240 milliseconds, adding ~480ms to a page load - quite a difference. Of course, these are optimal times, assuming the satellite is directly overhead.
That said, it does mention a constellation of three satellites, and there's no way that this could be practical with three satellites in a low- or even medium-earth orbit that I can see. Bandwidth is great, but latency is killer.
Move to Europe - we have a choice of carriers all across europe who can offer this :)
8.2 Mbps to 4k terminals.
Advanced EHF is designed to provide 24 hour coverage from 65 North, to 65 South across the K and Ka sub bands, and when combined with the prototyped Extended Data Rate (XDR) terminals and systems, will offer up to 8.2 Mbps data rates for around 4,000 terminals in concurrent use per satellite footprint (whether that scales to 12,000 systems in concurrent use globally isn't clear from source material).
Compared to current satellite rates, this is pretty good. Additionally, this allows them to bounce satellite signals quickly and reliably around the globe before having to incurr the atmosphere penalty.
However, if you're looking for replacement for WiFi, a final 802.11N spec is only about 10 years off.
The ______ Agenda
Satellite > Base Station > Your Mobile Device
That's how I imagine it would work. Honestly, do you really think that there are going to be thousands upon thousands of direct connections to the satellites? They would probably have to be sent through switches anyway, so so long as the base station's dish doesn't get tampered with it would work just fine.
10Ghz Space to Base Station, and a more stable protocol (Wireless N, 3G, etc.) to your mobile device.
Random Thoughts From A Diseased Mind (Not For Dummies)