Friday, February 17, 2012

Did The FCC Just Grow a Pair?

Long time readers of these rants will remember that I spent a couple of posts writing about a company called Lightsquared and how much corruption is involved in what they're doing.  I'll do the "executive summary" in a second, but if you want deep background, the posts in order are here (1), here (2), and the really big one.  There was even more that I didn't cover. 

The executive summary on Lightsquared is a story of the same sort of corrupt, crony socialism that the Obama administration seems to be setting new records in.  Think Solyndra in broadband instead of solar cells.  Lightsquared got the idea that they could use spectrum allocated to satellite services for a terrestrial broadband service.  The satellite spectrum they wanted to use was the spectrum that GPS uses.  For a couple of technical reasons, this an exceptionally bad idea - for the GPS users.  With about a billion and six cheap GPS receivers in use now; embedded in smart phones, car navigation systems, runner's and cyclist's computers and everything down to and including cereal boxes, Lightsquared could render them all useless as they roll out their money making scheme. 

A key part of this story is that the FCC allowed Lightsquared unusual (some would say illegal) access to people and then spectrum, to keep this dream going.  They granted them special waivers to run system tests "to see if there's harmful interference".  This was totally unnecessary; I routinely give problems like this to new grads and junior engineers; the signal levels can be calculated with straightforward models and you can easily see that the GPS receivers would be unable to process the satellites (although you do need to know some details about GPS receivers and how they work). 

Yesterday, I got an email from a long time friend, one of our top GPS and navigation gurus, that says the FCC has "Moved to Kill Off Lightsquared".
On Tuesday, Lawrence Strickling, the assistant secretary for communications and information at the Commerce Department, said government testing showed LightSquared's network would cause widespread problems with GPS devices, including ones used by pilots to prevent their airplanes from crashing.

"We conclude at this time that there are no mitigation strategies that both solve the interference issues and provide LightSquared with an adequate commercial network deployment," Strickling wrote in a letter to FCC Chairman Julius Genachowski.
Lawrence Strickling is the head of the Nation Telecommunication and Information Administration, the NTIA, a group chartered to provide technical guidance.  Their judgement was that it would take too much money and time to modify GPS receivers for everyone else in America so that Lightsquared could build their service out. 

With an expected market in the "many billion$", you should not be surprised to learn that Lightsquared has vowed to fight the FCC ruling.  They didn't get this far by not spreading money around to get their preferential treatment, so you can expect more "lobbying". 

I'm a receiver designer, and I can think of ways that should make a GPS receiver work in the presence of those Lightsquared signals.  The first big problem is what the NTIA said: there's the previously mentioned billion and six GPS-enabled devices out there that would have to be retrofitted.  Who pays for it?  How long would it take to design modifications and get modification supplies out?  Everything from military and commercial aircraft down to hikers, boaters and smartphones would need expensive, bulky modifications.  I suspect you'd find some receivers just too hard to modify that became useless.  Some receivers wouldn't fit in their current boxes.  New receivers would cost way too much and the market for GPS-enabled devices would be killed off because of the added costs. 

There's a reason why the spectrum was allocated as it was, with a low power service like GPS in a big swath relatively empty of nearby, loud signals.  You simply can't add a service like Lightsquared's in with an incompatible service that's already there - it's like adding the Broadband over Power Lines in the HF spectrum; the existing users are going to suffer.  It's nice to see the FCC man up for a change. 

1 comment:

  1. Yep. Extremely weak signals like GPS need a generous guard band on each side. The TV guys are currently fighting the same battle to try and keep broadband out of the spaces between the TV channels.