Why LightSquared cannot deploy LTE
extremetech.com
extremetech.com
It seems there may even be somewhat of a conspiracy about getting the spectrum approved.
See this press release from Chuck Grassley (R-IA): http://www.grassley.senate.gov/news/Article.cfm?customel_dat...
The details seem very murky, I welcome anyone that has a better understanding of how wireless networks work to please inform me.
All of that is just regulatory issues though. What really matters is interference; I don't (and the FCC doesn't seem to) care if a transmission comes from the ground or a satellite, so long as it doesn't mess with anybody else's services.
The two points of view are:
1) LightSquared is operating within their spectrum requirements, so while there are GPS receivers that will go haywire when they deploy, those GPS receivers are faulty (as they don't properly deal with neighboring transmissions on frequencies outside their band).
2) GPS should be granted a special exception to the rules about accepting interference as GPS is very important and the GPS signals are very weak, so therefore a receiver with little filtering on the front end is far superior to one more tolerant of high power signals on neighboring frequencies.
Both arguments have their merit, so it should be interesting to see how things play out. The more you look into how GPS works, it's a wonder that it works at all which such low powers (and satellites in the middle of a radiation belt, no less!)
Here's a couple of technical articles on the results of testing LightSquared vs. GPS. http://www.insidegnss.com/node/2630 http://www.pcmag.com/article2/0,2817,2389264,00.asp
"A report prepared by the Federal Aviation Administration's Navigation Services division essentially attributes 794 deaths and over $72 billion in additional costs to U.S. taxpayers if the LightSquared LTE system is implemented."
I'm willing to accept that not breaking GPS receivers is a good thing, and that allowing Garmin et.al. to sell cheap receivers by assuming neighboring bands they do not have licenses to are unused is possibly a good thing.
But, having an independent, nationwide, high speed internet choice is definitely a good thing.
The FCC should take a frequency allocated to government use and swap it to Lightspeed so they have bandwidth they can use. The existing users will pitch a fit about the expense of moving, but a new nationwide cellular internet player will likely save billions of dollars for consumers.
Users of adjacent spectrum designed their products properly for being adjacent to lower powered satellite signals. They weren't designed to filter out the much higher power terrestrial signals that Lightspeed is vying for.
The FCC is not denying Lightspeed the use of their licensed spectrum; they are not letting Lightspeed redefine their license to be something different than it is.
The bottom line is that the US has suspiciously high wireless data costs and a duopoly controlling the market. It's either make more players, effectively regulate the existing players, or allow the overpriced drag on consumers to persist.
There are only a quarter million airplanes in the US. Retrofit all of their navigation aids systems and free up a couple hundred MHz of bandwidth and you'd still pay for it with one year's savings from the mobile internet consumers. (And probably have better navigation in the planes.)
That's wrong. Only specific bands of wireless are unregulated; the bands at issue here are heavily regulated and are restricted to low-power satellite transmissions. Lightsquared had a conditional use permit to use the spectrum it purchased for alternative purpose but only if it could show that it would not interfere with the use of other low powered satellite transmission spectrums. Light-squared failed to do so.
An example that has been brought up before: its as if Lightsquared bought a house in a residential neighborhood, zoned for residential, and then tried to demand the right to use it as a venue for holding large-scale commercial concerts.
It's kind of like buying land zoned for industrial use next to the airport because you can get it rezoned for residential and make a ton of money. And the airport is saying WTF, now we're going to have to deal with local voters who will want us to change the way we do things.
If you're going to do this sort of thing, you need to make sure you have your engineering down pat, and your local politicians and regulators in your pocket.
see http://brontecapital.blogspot.com/2012/02/lightsquared-some-...
Personally, I think it makes sense to declare a quiet zone around the GPS frequencies if it enables smaller, cheaper, and lower power consuming GPS receivers. But that should involve relocating the existing license holders.
This is an insane oversimplification. RTFA -- that part of spectrum was never supposed by used by any terrestrial transmitters. GPS and other services were built under the promise that they would not have to contend with powerful, localized transmissions on adjacent channels. There are strong technical reasons why designing receivers to be immune to such adjacent-channel interference is impractical.
The FCC tried to let bureaucrats instead of engineers run the show, and unsurprisingly it's come back to bite them.
The problem isn't the noise, it's the volume. The volume alone would overwhelm the GPS filters' ability to filter out the out-of-band noise.
I am by no means an expert on the technical reasons for the interference with GPS, however, I work in the heavy highway construction industry and LightSquared's use of the spectrum is of real concern. The level of accuracy of current GPS guidance systems for construction equipment is astounding and enables significant improvements in job productivity over conventional practices.
I hope the truth and or a solution is discovered, as I do like the idea behind LightSquared and would use the service if available.