One of the issues I still don’t fully understand is the proposed reliance on satellite for backhaul by LightSquared, the proposed new Long Term Evolution service provider in the United States that hopes to use frequencies originally allocated for satellite communications.
LightSquared hopes to use the spectrum to create a national wholesale Long Term Evolution network.
But the reliance on a space segment for backhaul strikes me as less than optimal, given the latency introduced by the lengthy space segment, and the processing that might be required to support real-time services such as gaming, videoconferencing, voice and some enterprise apps.
I am told there are new coding techniques that allow satellite networks to support voice communications where it would have been quite difficult in the past. But I’m not so sure those techniques are cheap enough to deploy in a consumer setting.
A study by The Rural Mobile and Broadband Alliance (RuMBA) USA points out latency differences between fixed-line and mobile or satellite broadband. “If you ping a typical wireless access point within a home or small office network you should see an average latency of about 2 ms,” says Stephen Cobb, a consultant who prepared the report. See
http://rumbausa.ning.com/.
“If you are on a cable or DSL connection to the Internet and ping a commercial website like www.bankofamerica.com, you will see latency of about 60 ms. Unfortunately, a satellite Internet connection is likely to have a latency of 600 ms or more when contacting the same
website,” says Cobb.
Latency is not an overwhelming issue for some operations, such as casual Web surfing or even pre-recorded video, if the buffer is big enough. But it strikes me that relying on satellite backhaul as possibly difficult, especially for real-time services.
