I'm with lightsquared
Seems like they are bending over backwards to fix a situation not of their making.
Either the regulators got it wrong or the gps manufacturers have and should be at the pointy end of a product recall or class action.
LightSquared has filed a petition for Declaratory Ruling with the FCC for confirmation of its right to exist, as it's running out of cash fast and needs a decision. The company was expecting a decision by the end of the year, but confidence in its plan has been shaken by the selective leaking of test results and ongoing claims …
The GPS band was not there. The GPS manufacturers cut corners and sold devices that did not conform to the standards and listened to bands outside of those licensed for GPS use. The fact that LightSquared is attempting to use the previous satellite bands for terrestrial network makes no difference.
Why license specific band if one group is going to be allowed to interfere with anothers ability to use a frequency they legally have the right to use. And they do have the legal right to use it because the FCC granted them the license change. They might have been dumb to purchase the license knowing that the GPS manufacturers had already gamed the system to reduce their device cost.
What standards didn't they conform to? The Document lightsquared have been waveing around clearly states that it's not a standards document for recievers but for the signals transmitted by the satellites.
The issue is that there is no such thing as a perfect RF filter. You can't get ~130dB of attenuation at 1559MHz and 0dB with 0 phase distortion at 1560MHz. Which is a pity since that's the magic filter you would need for lightsquared to have zero impact on GPS.
This is why similar uses are grouped together, if you put all the space to earth signals in the same frequency range then all the signals are at about the same strength and you only need filters with achievable characteristics. This is a long standing internationally followed practice.
It is also something Lightsquared want to ignore.
The only reason this got this far is that until about a year ago no one believed the FCC could be stupid enough to even consider allowing this.
did the FCC sell the frequency to LightSquared, if they knew that they wouldn't be able to use it?
The FCC have sold the band, LightSquared have a right to use the band, if the GPS industry have not been sticking to their spectrum and can't cope with "noise" coming from an area they shouldn't be listening to anyway, that is the GPS industry's problem.
If LightSquared have even developed an add-on gizmo which corrects the problem for "faulty" GPS devices, I don't see the GPS industry has a leg to stand on.
We also rely too heavily on GPS. When I was growing up, we had to learn to use maps. When I did my offshore sailing stint, we had a GPS, but "you should nevr trust it." We could use it for setting way-points and sail towards them, but we still had to take sightings etc. and plot our course on a map, "just in case."
The human race has managed to go centuries without GPS and managed to discover most of the world. Now, we don't even seem to be capable of popping off to the corner shop, without first programming it into the GPS and when it goes wrong, people panic and seem to be incapable of using common sense.
I drove from Munich to Bremen a couple of years back and the in-car GPS couldn't get a signal for some reason. It told me to head south, coming out of Munich. As I needed to go north, I ignored the GPS. An hour later, I was happily thundering up the autobahn in a northerly direction, the GPS had me doing 120mph through a village and was trying to keep itself on the designated roads, whilst flashing up warning that I should observe local speed restrictions! Another hour and I was coming up on Frankfurt, whilst the GPS had me in the middle of a Lake Constance! Using my general knowledge of German geography, I got to Bremen without any problems, no wrong turns and no delays.
More often than not, the GPS systems I've used seem to take some very strange routes. For a reasonably long trip, I can generally cut off a good 50 - 60KM by ignoring the suggested route and driving using common sense.
In short, LS should be allowed to use the spectrum they've paid for and the GPS industry should get its rear in gear and sort out their own problems. They knew that the neighbouring spectrum could be used some day, but ignored the fact that their kit wouldn't be able to cope with that in order to make a quick buck, now they should get their own house in order!
The FCC sold a band that COULD be used. LightSquared bought the band to use for SATELLITE to GROUND communications. This is exactly what the GPS band is doing. What this band COULD NOT be used for is GROUND to GROUND communications. So LightSquared bought the band that could only be used one-way and then they LATER changed their mind of how they wanted to use it. So it is not that the FCC sold them something that couldn't be used, but that LightSquared NOW wants to use it differently.
Car analogy. You wanted to buy something that was extremely economical to buy and run, so you bought a FIAT 500. 12-months later you wife has triplets and you decided you want a 40-foot boat. You no longer have the right vehicle for the job now do you? This is what LightSquared has done. if they would implement that network that originally planned for, they would not be a single issue with GPS. It is how they currently want to implement their network that will cause issues. Seriously, this is not that hard to grasp.
GPS manufacturers did not cut corners, they designed exactly to spec.
The original FCC band plan was laid out specifically to keep relatively weak signals in the same range of frequencies because of the difficulty of building sensitive receivers with exceptional adjacent channel rejection. Specifically to keep strong signals away from weak signals. Exactly what LightSquared is trying to undo.
"The fact that LightSquared is attempting to use the previous satellite bands for terrestrial network makes no difference."
Yes it does. If the spectrum was used as originally defined, there would be no interference at all.
Look at radio stations. notice how there is gaps between them? If two stations were across town from each other and in directly adjacent bands, they would interfere with each other. When you are close to one and tuned to the other, you won't get much of it at all. This is well known and stations make sure they are not in direct adjacent bands in areas. The same is said for HDTV. In fact, this is what the FCC says about it:
"When a signal is 10 to 15 times more powerful than that of an adjacent channel station, most receivers become unable to receive the weaker station. To receive a far away station, you might need to use a directional antenna to reduce the strength of a nearby adjacent channel station. See “Nulls in radiation pattern”. But if both stations are in the exact same direction you might be out of luck. There are some frequency selective filters that can “trap” out a channel, but they are seldom able to reduce an adjacent channel by more than half."
Directional antennas are not an option with GPS receivers now are they? Notice how the filters are not able to fully solve the problem and that is for two stations on different channels and the same output power. The LightSquared towers will be putting out a much more powerful signal than what the GPS receiver will receive from the satellite due to the distance between them.
LightSquared should have bought the correct spectrum for their needs; they did not.
"LightSquared should have bought the correct spectrum for their needs; they did not."
They couldn't. All the available spectrum's already been taken up. A de jure oligopoly is in effect because everyone who bought spectrum intends to use it, so there's no spectrum to resell. The mobile spectrum market is essentially closed unless you disrupt the market. LightSquared is essentially doing the only thing it possibly can do as a mobile upstart. If you can't get into the market the normal way, DISRUPT it.
Sure they could have, there was no available spectrum AT THAT TIME! That means they either wait, or try to buy the spectrum from another party. Since 1994 the FCC has had 87 auctions for spectrum. On average, that is nearly 5 per year.
"LightSquared controls 59 MHz of the United States spectrum (1525-1559 MHz) and received FCC authorization in 2004 to use this L-Band spectrum to build its nationwide 4G-LTE wireless broadband network integrated with satellite coverage."
In 2002 there was the 700Mhz auction. Clearly they could have bought spectrum then. Maybe they didn't because they didn't have the capital; not the problem of the FCC or the taxpayers.
In 2005 there was a PCS auction. Where was LightSquared?
in 2006 the FCC had an AWS auction. Where was LightSquared this time?
There are three auctions right there with prime spectrum for mobile use. So cut the chit about that they couldn't buy the correct spectrum. The reality is, they bought spectrum that no one wanted for a cheap price and now they are trying to game the system.
"The problem is that the (weak) GPS signal is right beside that licensed by LightSquared for mobile telephones."
The band is NOT licensed for mobile telephones. It is licensed for transmission from SATELLITES to ground stations. If Lightsquared do that, everyone will be happy.
But NO, lightsquared have realised that satellites are very expensive, and offer very limited bandwidth. So they want to transmit from GROUNDSTATIONS to groundstations. The problem with this is that where the signals leave the groundstations, they are about a billion times more powerful than the signals from satellites and so wipe out everything else.
Imagine that you buy a nice place out in the countryside for birdwatching, and then a new person buys the place next door for the same, but then changes their mind and decides to use if for nuclear weapon testing instead... How does your birdwatching go? How about when your neighbour says that you just need to build 1000m high walls around your land so that the birds are not disturbed by the bombs?
more like you buy a place in the country to go star gazing, a new neighbour buys land to do the same thing and decides to watch birds instead, with flood lighting at night.
They apologise and offer you a tube to shield your telescope from their lights, so you can continue to star gaze with minimal interference.
Its a bit like Ethernet over Mains kit here. I've a quantity of it, but wouldn't want to be responsible for disrupting someone else's legitimate radio setup, for example (previous articles on El Reg refer). If I even suspected a neighbour had a setup that was affected I'd check and accept the hit and replace my kit even though I am an innocent end purchaser.
It might also make the manufacturers pay a bit more attention to standards and build quality. Its a crowded spectrum out there and we have to play fair. I've had to replace a lot of service radios as the older ones affect too wide a frequency either side of the one issued, and thats no longer acceptable, howver the change coupled with newer/better tech means that there are now more channels to go around, so its a general win.
As has been pointed out, they tried to game the system and lied about it. They licensed a band designated for one purpose and tried to repurpose it, falsified interference data, and pretty much engaged in criminal behavior. That's the real issue - why hasn't the DOJ put these guys away?
LightSquared have licenced a band designated for Sat-to-ground communication, and are trying to use it for ground-to-ground communication.
Sat-to-ground means that the signal strength at all points on the Earth's surface will be below a certain threshold, regardless of location.
Secondly, the range of signal strengths in the 'coverage area' will also be very uniform as the distance doesn't change much within the area. Eg for US coverage you can't significantly change your distance to a geostationary satellite covering the USA without getting into a rocket.
Thus the signal strength of all competing signals in the band are within similar limits - a receiver will never need to cope with an unwanted signal more than a few dBm above the wanted signal.
All GPS (and satcom equipment*) were thus designed based on these fundamentals.
Ground-to-ground negates both of these protections - it is easy for someone to halve the distance to a ground tower, quadrupling the signal strength. If the system is designed with 100 mile range, then all receivers will have to deal with 1 mile range (and less!) as well as 100 mile range - thus the unwanted signal strength in a pretty close band could easily be over 40dB stronger than the wanted.
- Every halving of the distance is ~6dB increase.
That's a huge filter requirement (much tighter than WiFi), and I really doubt that any practical GPS receiver could really cope - tight filters are physically large, and GPS units are really, really tiny these days with very tight power budgets.
The real problem here is that LightSquared appear to think they were given a go-ahead for this a while ago, when there is no way this should have occurred. I suspect that what actually happened is that the FCC said something like "Ok, if you can prove it doesn't break GPS and other satcom", and LightSquared are now claiming "If GPS is redesigned it seems ok" as a yes. It's not - you do not get to move the goalposts after the game is over.
If this does get a go-ahead, it can only be in the basis that LightSquared pay the full cost of rebuilding/replacing all affected units - worldwide, including home visits out of hours.
- Tourists are going to be rather annoyed if their EU GPS navigation thingy doesn't work in the US after they shell out for the US maps.
*The ground end of Satcom almost always has a directional antenna. Even Iridium uses a "point it upwards" antenna, although it's clearly not as highly directional as a dish or bucket.
"That's a huge filter requirement (much tighter than WiFi), and I really doubt that any practical GPS receiver could really cope - tight filters are physically large, and GPS units are really, really tiny these days with very tight power budgets."
Yep. I imagine with enough cascaded filter circuits, the GPS boys could get rid of all but the most egregious cross-band interference, but you'd need a mulit-rackspace device to house all that gear. Hardly the thing to mount in your car or carry in a handheld device. Plus you'd need to stick a healthy pre-amp onto the front end of the device to guarantee you had enough usable signal coming out the tail end of all that filtration.
GPS devices could be attached to directional external antenna arrays, but the facts that a) they rely on tuning signals from multiple birds at once and would require either multiple aim-able "tight" antennas, or one "loose" antenna (which tends to defeat the purpose of using directional arrays in the first place), and b) they're most often used in mobile applications and traveling on constantly changing paths, both point toward that being an impossibly large and expensive fix.
Unless an ideal super-selective miniature filter (for hand-held GPS receivers) is invented, if Lightsquared has its way GPS will not be available in the vicinity of their towers.
No way you can filter out a signal 10 MHz away that is 100dB more powerful (10^10 times!)
Filters with this steep bandpass characteristics exist, but they are either the size of a fire extinguisher, or smaller but liquid nitrogen cooled superconducter filter. Not very portable!
I personally have had serious problems with professional quality GPS timing receivers with triple-filtered antennas because of local signals more than 70 MHz below the 1475 MHz GPS frequency.
If the MSS band was originally allocated only for satellite to ground use, things must stay this way, and the FCC should have NEVER even hinted of any possibility of using terrestial transmitters in this band.
It seems to me that Lightsquared bribed some technically incompetent official(s) at the FCC, and now they are trying to bully everybody else so that they can have their way.
Nooooo way, they can use the MSS band, but only from satellites!http://www.theregister.co.uk/Design/graphics/icons/comment/stop_32.png
There's no debate about this one. Lightsquared cannot be allowed to transmit high power signals that might interfere with existing GPS signals. End of.
Frankly its only because of money that its even being talked about. But tough, Lightsquared get told to make do with much lower power signals - or held liable for the interference caused. Because otherwise the FCC gets held accountable for not stopping them.
While at the moment its a peculiarly american brand of idiocy, what happens when some yank takes their mobile on holiday? Jamming of GPS is considered a crime in most countries, unless you're government.
"Frankly it's only because of money that it's even being talked about."
Well that and the fact that one of the earlier investors in the scheme is President Obama, who also accepted the maximum legal campaign contribution from several of the muckety-mucks behind LightSquared. A conspiratorial mind would see lots of dots to connect here. And honestly, with all the other instances and allegations of "pay to play" swirling around this administration, well the LightSquared imbroglio looks depressingly familiar.
So make that 'money and power' and you've got yourself a winner. Of course the two can be and often are intertwined to a degree - I get that - but power's a crucial player in this one, no?
As someone not too well versed in signals of various types I have a question.
As far as I can tell the GPS companies have been licensed to use some particular range of frequencies - let's say "5-10". The FCC have then allowed Lightsquared to use a range of frenquencies which include nearby ones - say "0-4".
It seems from the article that the problem is that GPS also uses - in some instances - 3 & 4 (and 11 & 12) for their purposes. In which case Lightsquared using those frequencies poses a problem.
From the comments it seems more like Lightsquared using 0-4 will also interfere with 5 & 6 and thereby pose problems for the GPS.
If it's the first case - then surely the fault must lie with the GPS people (Who perhaps should've licensed nearby frequencies, if they knew they would be using them - or that anyone else using them would interfere).
If it's the second case then the fault must lie with the FCC. Since they shouldn't have licensed frequencies to a company who, by using those frequencies would damage users of other frequencies.
A third option being that the FCC and Lightsquared made a sort of deal that the second case might be true, but Lightsquared were to make sure it wouldn't be. In which case Lightsquared must have sole responsibility for making that come true.
Can someone clarify any of this?
And I realise this is a simplification of the matter of overlapping frequencies and signal strength, however I need simple - for I am a product of an ADD-ridden generation! (Hence Paris Hilton!)
Think of yourself trying to listen to a faint shoddily-recorded MP3 (let's assume for legal reasons it's a self-recorded dictation) from the speaker of your phone. It's very hard to hear, so you basically have to put the phone right up to your ear to hear it clearly enough to understand.
Now, imagine trying to achieve the same feat while there's a death metal band performing nearby. In contrast to the tinny sound coming from your phone, the band's using huge speakers and are playing very intense and very deep music. So you try to cup your ear and do other things to filter out the music. Thing is, not only is it very loud (so that you're hard pressed to muffle it all out) but also so deep that you tend to FEEL as well as HEAR the music. No filter you could cook up is going to cut it in this case because the phone itself is starting to shake.
There's only one practical solution: put some distance between you and the band. But there's a problem. You were here first so you have dibs on the spot, but the band counters that there's nowhere else to play. Either other, bigger bands have already booked all the other possible spots. And this is their one and only chance for a breakout performance.
The FCC should never have granted the change of use. Lightsquared cannot be allowed to go ahead, but if they are prevented from doing so then the FCC can and should be sued. The FCC has created a horrible mess and there's no clean way out of it. I do wonder what (or how much?) persuaded the FCC to agree to the change?
Agreed. If they sold LightSquared the spectrum and agreed to LS's proposed change of use, then LS should be in the clear, it is the FCC that is in the wrong.
It seems that LS have bent over backwards to try and help the GPS manufacturers - although the article makes it sound like the GPS manufacturers are in the wrong by "listening outside their spectrum," hence my reply higher up saying the GPS manufacturers should get their house in order.
That said, I've never found GPS to be particularly reliable and have always used it as a secondary system, using maps, charts or post-it notes as a primary routing system.
The FCC approved the change, then Light Squared went ahead with their plans. I grant the arguments on behalf of GPS, Light Squared should be able to build out their network. But that means the FCC needs to revoke the change, and at that point the FCC has to make Light Squared whole again because of the false or misleading rulings that permitted Light Squared to proceed in the first place.
And yes, I know. That means MY taxes are going up, not that the FCC lost anything. I'd [b] like [/b] to see heads at the FCC roll, but I know that won't happen either.
Not really, LightSquared could try to sue, but they will have a tough fight. This is what the waiver the FCC provided actually says:
"41. We agree on the need to address the potential interference concerns regarding GPS as
LightSquared moves forward with plans to deploy and commence commercial operations on its
network.144 Further, we believe that establishing a working group that brings LightSquared and the GPS
community together to address these interference issues expeditiously would serve the public interest.
We envision a working group in which cooperative and candid discussions can ensue, and where
information, including proprietary information, can be shared among the participants with appropriate
measures in place to protect the confidentiality of that information. Commission staff will work with
NTIA, LightSquared, and the GPS community, including appropriate Federal agencies, to establish a
working group to fully study the potential for overload interference to GPS devices and to identify
any measures necessary to prevent harmful interference to GPS. As a condition of granting this waiver,
the process described below addressing the interference concerns regarding GPS must be completed to the
Commission’s satisfaction before LightSquared commences offering commercial service pursuant to this
waiver on its L-band MSS frequencies."
See the part that concerns must be completed to the Commission's satisfaction prior to LightSquared offering commercial service? So there we go, LightSquared has failed to do that and in fact have lied every step along the the way. The FCC should say that the waiver is null and void and if LightSquared even attempts a lawsuit, the DOJ subpoenas the records of LightSquared. They will clearly find reports that LightSquared submitted were falsified. The DOJ then starts the criminal investigation into LightSquared and the leaders of the company and try them in a court of law. LightSquared would drop their opposition long before a trial was ever scheduled as jail time is not what the leaders of LightSquared want.
The waiver is here:
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