FCC Bars Lightsquared From Using Airwaves 178
New submitter mc6809e writes with news that Lightsquared might have just been killed. From the article: "A proposed wireless broadband network that would provide voice and Internet service using airwaves once reserved for satellite-telephone transmissions should be shelved because it interferes with GPS technology, the Federal Communications Commission said Tuesday. The news appears to squash the near-term hopes for the network pushed by LightSquared, a Virginia company that is majority-owned by Philip Falcone, a New York hedge fund manager."
LightSquared, naturally, continues to deny that the interference is real.
Sucks for Lightsquared (Score:1, Interesting)
It's my understanding* that Lightsquared's equipment was never the issue, but rather the GPS equipment that got interference were just poorly designed. If the GPS equipment was held to the standards it should have been, Lightsquared's equipment wouldn't have interfered. Yet Lightsquared are the ones being shafted, simply because GPS is "too important". Really, the FCC and/or the GPS equipment manufacturer should be the ones being penalised. FCC beucase it's their job to look after this sort of thing and the
Re:Sucks for Lightsquared (Score:5, Insightful)
Really, the FCC and/or the GPS equipment manufacturer should be the ones being penalised.
As a practical matter, there's no way to do that. If you allow Lightspeed to operate, you penalize the USERS of the (allegedly) badly designed GPS devices. It does suck to be Lightspeed, because GPS really is much more important than them.
Re:Sucks for Lightsquared (Score:5, Insightful)
> you penalize the USERS of the (allegedly) badly designed GPS devices
I maintain a 50,000 watt AM and two 100,000 watt FMs, and we get interference complaints all the time. The only fair rule for EVERYONE involved is to say, "as long as I'm following the terms of my license, and I'm SURE that my transmitter isn't putting out unwanted products, there's nothing I can do."
I'm friendly; I offer tips and suggest filters; I help if I can. But there's really not much I can do if they have a cheap radio. Am I "penalizing" them for buying a $20 table radio from WalMart? I don't think so.
You say "allegedly," but believe me, some of the cheap Chinese junk (albeit with good-sounding American brand names) being sold now isn't worth the money to crush and melt it. I would be astonished if the same isn't true of GPS equipment.
Re:Sucks for Lightsquared (Score:5, Insightful)
And what if someone decided to operate a station on an adjacent frequency channel, with 10 megawatts of power? Or even half a channel over? (Rules? What rules? We just want a little variance in the rules!) Then suddenly people trying to receive your station get interference because the channel separation rules weren't designed for that kind of power on adjacent channels? The problem isn't "badly designed GPS devices", it's that this is a band which was allocated specifically for the purpose of satellite communication, which is by its very nature rather low-powered to begin with.
I'm almost surprised it took this long, except I'm sure there has been some ohbummer-related political interference going on behind the scenes. And it's probably still going on even now.
Re:Sucks for Lightsquared (Score:5, Informative)
And that's where the debate lies. LightSquared's license permits them two uses of the frequencies licensed:
LightSquared's argument is that they have met the second term of their license if they ensure that their earth-based transmitters do not leak out of their licensed bands, even if they interfere with licensed users of neighbouring bands; note that the FCC has been clear that one way to meet the second requirement is to replace receivers of the neighbouring bands with ones that cope with your interference, an option LS has rejected as impractical, as they cannot find affordable receivers that have both the GPS abilities of the receivers they're replacing and better rejection of LS's signals.
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If those complaints came from people who had bought those radios before you got those licenses and your license stipulated that you not interfere with their reception of other radio stations then your situation would be different.
Re:Sucks for Lightsquared (Score:5, Informative)
You understand radio a bit it seems. Here's what you're ignoring though, so follow me here: a high-precision GPS receiver must pick up signal at -165 dBm. This is right about at the noise floor. Its incredibly easy to cause interference with a receiver that must operate with these conditions, and incredibly difficult to design a filter that would actually be useful. You're talking about transmitters with 10^5 W output interfering with other transmitters in the same class. Its apples and oranges.
Re:Sucks for Lightsquared (Score:4, Insightful)
I'll bet you're not operating a terrestrial transmitter in a band that is restricted to satellite downlink are you? If you did, you would be shut down, and rightfully so.
The GPS gear was designed to operate adequately within the environment the FCC promised they would be in. LS begged the FCC to go back on that promise and was given every chance to demonstrate that it wouldn't cause a problem for any existing application. They failed to prove their case. End of story. Note that the FCC was under no obligation to even give them a chance to prove their case, they were entitled to just give them a flat NO.
Re:Sucks for Lightsquared (Score:5, Informative)
The GPS units are not faulty. The spectrum they use are reserved for SATELLITE reception, not terrestrial broadcast. The signal levels received are so incredibly weak, that it is quite difficult, certainly not cheap, to build filters to filter out a nearby signal that is several order of magnitude stronger than yours. The spectrum was reserved, by the FCC, such that the neighboring spectrum would be like weak signals, which makes building receivers with high sensitivity possible and affordable.
I am sorry, but it was lightspeed who deceptively came in, got the spectrum, then changed from a mostly satellite based service (which would have been fine in that spectrum), to one consisting of tens of thousands of TERRESTRIAL transmitters in the L1 band, that simply overpower the nearby satellite downlink signals.
You just cannot build a high sensitivity receiver with a filter strong enough to filter out that kind of interference.
The FCC never should have granted them a go ahead in that frequency band in the first place.
Re:Sucks for Lightsquared (Score:5, Informative)
I would also point out that the frequency band GPS and satellite signals are in are much cheaper than terrestrial frequencies. As such, Lightspeed abused a (poorly conceived) FCC ruling for filling in poor reception areas with local ground based transmitters, to take cheap satellite spectrum, and repurpose it for a very large and high-powered terrestrial network, without paying similar licensing fees other terrestrial providers have to pay for their spectrum.
The whole loophole started by the FCC allowing ground based transmitters in the L1 band, but the intent was to supplement poor reception of satellite signals with some ground based ones. They never intended it to be repurposed for massive scale and high powered ground transmitters everywhere.
The laws of physics don't work well with you here when you have very weak signals from space competing with local, very strong signals on the ground, and only a few MHz apart in the GHz range. That was the original reason satellite based signals have their OWN spectrum. While it stinks for Lightspeed, they should know they never should have really gotten that spectrum from the FCC in the first place. The FCC dropped the ball on this one, but perhaps that's not too surprising how much corporations can buy influence in Washington these days.
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This thread should consist of the above post, and nothing else. I work in the GPS field, and the above is 100 percent absolutely spot on - and put much better than I possibly could.
Re:Sucks for Lightsquared (Score:5, Informative)
The last time /. discussed this, it was pointed out that the spectrum L^2 was aiming for was intended for low-power satellite signals and was never intended to be used for (relatively) powerful ground stations. They were essentially trying to buy spectrum on-the-cheap and then repurpose it in a way that was virtually guaranteed to interfere with adjacent spectrum. So, while GPS devices could certainly be better-designed, this was more an incident of L^2 trying to abuse the system.
Physics, alas, makes for a harsh mistress.
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Physics, alas, makes for a harsh mistress.
Yeah, but that's because Physics is a old, hairy dude.
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Physics, alas, makes for a harsh mistress.
Yeah, but that's because Physics is a old, hairy dude.
?
Physics has to be a really curvy woman.
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Yes, lightsquared was taking advantage of the system. Absolutely. While it's not ethical, that kind of crap is pretty much legal in the states.
so it becomes a competitive question here - why aren't GPS devices better designed? why isn't L2 trying to avoid neighboring spectrum? etc. It's no longer "L2's fault" but both - to imply L2 when you acknowledge both have an issue (manufacturing to specs should be regulated by the FCC and isn't, yet FCC is regulating Lightsquared) is to focus on one side of the issue
Re:Sucks for Lightsquared (Score:5, Informative)
so it becomes a competitive question here - why aren't GPS devices better designed?
Because they were engineered with the constraints of their band in mind. If the rules of the band are such that you don't need to worry about a powerful signal on an adjacent frequency, designing a filter to deal with such an adjacent signal is unnecessary expense.
Re:Sucks for Lightsquared (Score:5, Insightful)
L2 made one big mistake. Stepping on a lot of toes? No biggie, happens all the time. Stepping on toes that are in a building with five sides? Might want to think about that.
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i wonder what are the nearest .mil bases to lightsquareds headquarters??
Oh gee im sorry but we seem to have had a navigation error
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According to this article: [sail-world.com]
Re:Sucks for Lightsquared (Score:5, Informative)
According to the actual 2003 decision by the FCC:
Today we decide to permit flexibility in the delivery of communications by Mobile Satellite Service (MSS) providers [cut]. Specifically, we permit MSS licensees to integrate ancillary terrestrial components (ATCs) into their MSS networks
...
We will authorize MSS ATC subject to conditions that ensure that the added terrestrial component remains ancillary to the principal MSS offering. We do not intend, nor will we permit, the terrestrial component to become a stand-alone service.
That is, the decision was to let those offering mobile satellite services the ability to enhance their networks. This guy wanted to create a stand-alone cell phone network, which was explicitly not permitted in the 2003 decision.
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I know that it is probably too much to ask, but if you had read some of the letter from the NTIA, they specifically mention that there are no performance standards for GPS equipment to be compared against. That is, no one ever told manufacturers of GPS equipment that they had to deal with so much interference in neighboring frequency bands. The result of this may be that some standards are developed, but that does nothing for the huge installed base of GPS receivers.
Re:Sucks for Lightsquared (Score:5, Informative)
It's my understanding* that Lightsquared's equipment was never the issue, but rather the GPS equipment that got interference were just poorly designed. If the GPS equipment was held to the standards it should have been, Lightsquared's equipment wouldn't have interfered. Yet Lightsquared are the ones being shafted, simply because GPS is "too important".
That's not quite true. LS basically bought up a *satellite* band and tried to repurpose it for ground communications. It was then discovered that doing this caused some GPS equipment to malfunction. Whether or not you consider this GPS equipment to be "poorly designed", the fact remains that it was working absolutely fine for decades and LS's attempts to repurpose the ajacent band causes it to stop working. Expecting millions of GPS users to upgrade their GPS receivers just because LS wants to repurpose an existing band for a new use is ridiculous. On the other hand, if LS wants to buy shiny new GPS receivers for all these end-users...
So no, LS isn't "being shafted" - they purchased a satellite band with the intention of using it for ground communications, rather than its existing use, badgered the FCC into letting them repurpose it and then cried when it was found that this repurposing wasn't compatable with millions of existing devices.
Re:Sucks for Lightsquared (Score:5, Informative)
Wow. You couldn't be more confused. Analog TV operated in 54-88 MHz, 174-216 MHz (VHF), and 470-890 MHz (UHF) bands. GPS is up above 1 GHz, 1.57542 GHz (L1 signal) and 1.2276 GHz (L2 signal) being the primary signals. The frequencies that Lightsquared wants to use have nothing to do with the any spectrum which was previously used for TV.
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I'm guessing you were asleep when all the coupons for free digital tv receivers were given out, god that must have been a nice nap you had.
Plus paying $30 for a converter (and often $0) is very different than paying $20000 for a new GPS (yes, the aircraft ones cost around that much).
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In my effort to show how the government can essentially force consumers to buy new gear because the old crap will stop working, I confused my spectrums. (I was also discussing the new deployments of "Super WiFi" with my coworkers so that probably had a bit of an effect)
My depest heartfelt apologies. Apparently I offended your superior intellect(s). I'll be in the corner commiting hara-kiri for such an aggregious mistake. /snark
The point was that there is precedent in forcing a technology offline. Not that i
Re:Sucks for Lightsquared (Score:5, Informative)
GPS receivers (and the filters in their electronics) were built with the assumption that neighboring frequencies would be used by other space-to-ground uses, and thus would have comparable signal strengths (that is, very low).
Having ground-based stations blasting out signals that are brazillions of times more powerful than the weak space-to-ground signals on adjacent frequencies would overwhelm the relatively weak signal from GPS. Filters that can allow the weak GPS signals through while blocking out the immensely more powerful signals on neighboring frequencies would be bulky and expensive. Devices not equipped with those specialized filters (that is, essentially every GPS receiver ever made) would be screwed.
I'm sure that if LightSquared wanted to use the frequencies they acquired for space-to-ground uses, the FCC would have very little trouble with it and the potential for interference with GPS would be essentially nil. Instead, LightSquared purchased (leased? I'm nowhere near an expert on this kind of thing.) these frequencies at a cheap price due to their being intended for space-to-ground use and was trying to change their classification to use them for ground-based transmitters (thus saving LightSquared tons of money acquiring spectrum). They gambled big and (rightfully) lost.
Reliable GPS service is more important than the communication network LightSquared proposed, particularly in regards to safe navigation for aircraft and vessels.
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Can I just say how much I like the term 'brazillion'? I'm going to start using now. Sorry to be OT. The rest of your argument is sound and I'd mod you up if I had the points today.
Re:Sucks for Lightsquared (Score:5, Informative)
Lightsquared "bought" this spectrum, much cheaper than similar spectrum allocated for terrestrial use. They then fast tracked a petition through the FCC to get authorized to use that spectrum terrestrially. The problem is, that produces much stronger signals than GPS receivers were designed to deal with.
If Lightsquared were to use the spectrum as originally intended, there would be no issue. Instead, they want to have their cake, and eat it too, by paying for relatively low cost satellite spectrum, but using it for terrestrial transmitters.
Re:Sucks for Lightsquared (Score:4, Informative)
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Where GPS is a politically entrenched industry with the FCC in their pockets, which gives them a long leash to hog all the spectral elbow room they can get away with.
GPS saw nothing but tumbleweeds, so it let itself go with lax filtering, and now it's "too big to fail" when LS shows up trying to move in next door.
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Actually GPS knew there was a regulatory requirement for "nothing but tumbleweeds" and designed their systems according to said regulatory requirement. The adjacent spectrum was also marked for satellite transmission. There was no reason for GPS manufacturers to assume that suddenly there would be powerful terrestrial transmitters sitting next door, as they were told the adjacent frequency bands would be used for similar low power signals.
Imagine you need to build a very loud factory. You go buy a parcel
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...and, yet, when someone wants to make an airport bigger or extend a railway for commuter service, all those people who complain are denounced as NIMBYs.
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Politics? Huh? (Score:2)
What does this have to do with politics? GPS operates in a satellite band, and the surrounding traffic is also supposed to be satellite. It is perfectly proper for GPS makers to design their filters around their expectations for surrounding traffic. It would have just been needless complexity and expense for zero end-user benefit to design them tighter.
If I build my house in the middle of nowhere surrounded by farmland, peace, and quiet, you can damn sure I'm going to protest when somebody tries to re-zo
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Some engineer did their homework. They decided to create a filter with the necessary -dB/octave roll-off needed to deal with the signals that could be expected in the real world.
In the real world, signals of the power that LightSquared wants to use were illegal at the time the GPS device was manufactured. As in, violators go to federal pound-me-in-the-ass prison.
So how, exactly, are their filters "lax", if they were designed to deal with the maximum power signals that were legal at the time of design?
Re:Sucks for Lightsquared (Score:5, Insightful)
Also, don't forget that radio signals aren't prefect pathways either and you can be broadcasting on one frequency and have it bleed over into another frequency. This is why radio stations and television channels are allocated in such a way that they aren't directly next to each other (think radio channel 100 and 100.1).
So in summary, this isn't an equipment problem but a physics problem: making the equipment better isn't going to help the fact that the signal would be drown out if Lighsquared were to broadcast on a satellite channel at terrestrial power levels.
Re:Sucks for Lightsquared (Score:5, Insightful)
On the one hand, being able to convert a swath of satellite-to-ground spectrum into ground-ground spectrum would be crazy valuable, and likely result in some very nice returns. On the other, trying to go up against the now-firmly-entrenched users of GPS(ie. almost everybody) is a risky move indeed.
Did they miscalculate the odds, or were they happy to take very bad odds for the possibility of extremely high returns?
Re:Sucks for Lightsquared (Score:5, Insightful)
it's more like getting a permit to open a bar next door to an observatory but the city strictly requires you to keep your outdoor lighting to a minimum so as not to disturb the telescope next door. yet you still put up a huge neon sign and searchlight and when the observatory complains that your light pollution has ruined its ability to gather data, you say 'it's not my fault your telescope sucks'.
Read 1950's science fiction much? (Score:2, Interesting)
http://www.archive.org/details/XMinus1_A [archive.org]
It was done in 1950's pulp sci-fi. Casinos operated near observatory and the casino firework shows prevented observatory from taking good pictures. Casinos paid politicians, so the observatory was left in the cold. The observatory then started offering "readings based on the stars" for free to tourists, and started singling out a casino a week as "bad luck" for the tourist until that casino stopped the fireworks. It was a pretty good story 60 years ago and stands
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rather the GPS equipment that got interference were just poorly designed. If the GPS equipment was held to the standards it should have been,
Blatantly false. Ask your closest EE to run the numbers. The numbers are utterly insane. You need something like multiple superconducting resonant cavities to pull this off. IF you were willing to ten-tuple the size of your cellphone and include a liquid helium fill port and dewar then it'll work, just fine. At least the liq He dewar will stop the phone from physically heating up as you talk on it.
Also they were very well designed to operate within and around a satellite to ground transmission band. P
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Outside of some limited consumer markets, or the occasional dramatic(and generally traumatic) forklift upgrade of some gigantic institutional system(usually still leaves a screen-scraper connected to the old system that everybody politely doesn't talk about hidden somewhere...), the clout of Stuff That Already Works is enormous compared to that of Stuff that Might Be Cool.
If it were merely a matter of forcing Garmin into a class act
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Your understanding is not correct. Had Lightsquared sought to use the satellite-only restricted band they bought for a satellite-based system, they would have been fine. Instead, they bought use of a satellite-only restricted band (which was cheap, because it's not useable for terrestrial-based transmitters, so nobody else really wanted it) and wanted to use it for a terrestrial-based system.
ALL RF transmissions affect nearby bands, not just those the transmitter is intended to use. While it's trivial fo
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It is the opposite, kind of.
Lightsquared's spectrum was meant for satellite, but wanted to use it as a primarily terrestrial communication spectrum. The GPS and Lightsquard's spectrums were setup assuming they were originating from satellites, and under those conditions shouldn't impede each other. GPS units, shoddy or not, were having trouble with bleed over from a signal far, far closer than ever intended to be.
Lightsquard isn't blameless. They wanted to do similar to what they were accusing the GPS man
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Based on the additional comments, I stand very much corrected. Looks like this was a LS blunder after all.
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No. Lightsquared knowingly bought a bit of low value spectrum that had a rather strong limitation placed on it. They knew about that limitation going in to the deal.
They then tried to greatly expand the value of their spectrum by seeking a special exemption. They were given every chance to show that the restriction was unnecessary, but failed to do so. For that reason, the restriction stands.
The GPS equipment designers designed for cost and performance knowing that that restriction was in place. They design
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Please read up on the issue ... the frequency L^2 purchased were always licensed for satellite-to-ground communication, which would have been fine for L^2 to do. But in order to get better coverage in dense areas like cities, they planed on putting up earth-based relay stations, which would have drowned out any adjacent frequency band ... I read a comparison somewhere where the regular communication was compared to a regular light bulb in orbit, say 100W ... while it's already hard to see by itself, now ima
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GPS uses a very low power signal from the orbiting satellites. Trying to add filters for the Lightsquared band to that would reduce the signal strength even more. Lightsquared's signals would have been terrestrial in origin and 100 times the signal strength of the the GPS signal. It's just not a workable combination.
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It might not change whether LS gets to use the spectrum it paid for, but it means everything when determining who, if anyone, coughs up to LS to compensate for a blunder that may or may not have been theirs.
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They certainly may use the spectrum they paid for as a satellite downlink (the permitted use) if they like, or they can sell it off. LS screwed up by licensing spectrum with a single permitted use with the intention of using it in a forbidden way. The restriction wasn't a secret, they knew very well that it existed from day 1.
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my understanding is that they everyone is at fault:
gps manufacturer for going the cheapest route
lightsquared for purchasing a licence for satellite bandwidth and pushing unapproved high powered land based electromagnetic waves within the spectrum
fcc for applying and approval badge on cheapo gps receivers and not foretelling the problem; it's true they did not certify the tolerance to harmful frequencies but the non emission of them, but they're also the manager of the spectrum and should have put the rules
Re:Sucks for Lightsquared (Score:5, Informative)
Let's be clear - the FCC is not in the business of validating that any particular device is generally well-made or robustly-designed. Their one and only concern wrt to type acceptance is the RF _emissions_ of the device. They do not require testing of receivers for susceptibility to nearby carriers, intermodulation, desense or anything else, only their (in the case of a receiver, unintentional-) emissions. All not-otherwise licensed equipment carries the all-too familiar Part 15 warning [gpo.gov] about not causing and having to accept interference.
Re:Sucks for Lightsquared (Score:5, Insightful)
What's the sense in building a receiver to reject adjacent channel interference that, via an FCC band plan, was never meant to exist? Managing the spectrum so that large amplitude signals are not present is a whale of a lot cheaper than turning a $100 GPS receiver into a $200 GPS receiver when the design and construction of the filtering necessary to reject the supposedly non-existent adjacent channel high power signal causes the doubling of the price.
If everyone just goes by the band plan, and doesn't try to do some end-run around the intent of the rules, then we can have $100 GPS receivers instead of $200 GPS receivers. I think building them cheaper is the better idea.
Re:Sucks for Lightsquared (Score:5, Informative)
The rules upfront were clear; adjacent bands were for low power satellite use only.
The fact is that Lightsquared thought it could buy the influence to screw everybody else while getting richer. There is a reason the band they bought was so cheap.
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I'm a little surprised their government sociopath bribe recipients failed to deliver.
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yep. lobbying will again be squashing potential competition.
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They are honoring it. They licensed the spectrum for use as a satellite downlink. If LS would care to use it for that, they may certainly do so.
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You're missing a big point. Adjacent carriers in the FM band are all transmitting at comparatively the same SIGNAL STRENGTH. As such, filter design is not too hard to do. Filters are not perfect, and some adjacent channels will always leak through. If the adjacent channels are attenuated enough, you get good reception. If all the signals start out at about the same signal strength this works ok.
But a ground based transmitter adjacent to a weak satellite downlink? You're starting with the two signals many ma
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Argh! Where do I start?
For one thing, you mean MHz. With a capital M. A lower case m would be milli. FM stations are not separated by millihertz.
For two, it is NOTHING like that. It's more like designing an FM radio receiver, and then someone comes in and starts blasting AM all over your frequency band.
Remember that when the GPS devices were designed and manufactured, signals of the power that LightSquared wants to use were ILLEGAL. As in, violators go to federal pound-me-in-the-ass prison.
Do you real
GPS was here first, end of story. (Score:3, Insightful)
The FCC made a good and wise decision in this situation.
It is unrealistic to expect the desires of a company which wants
only to make money should override the safety of a public
which depends increasingly on GPS.
Look for Iran to implement this technology (Score:5, Funny)
I mean if it gives you broadband, voice and blocks GPS guided missiles, what more could you want?
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In addition, GPS-guided missiles are designed to still function well under loss of GPS signal. The military knows full well how brittle GPS can be.
Massive simplification (Score:5, Informative)
"A proposed wireless broadband network that would provide voice and Internet service using airwaves once reserved for satellite-telephone transmissions should be shelved because it interferes with GPS technology, the Federal Communications Commission said Tuesday
That's a massive simplification. They sell mobile satellite internet, and have done so for a long time, and will do so into the indeterminate future, this has nothing to do with that.
The LS idea was to provide a backend carrier to local on ground cellular providers for internet traffic. Same as your off the shelf 3G service you now "enjoy" but instead of your greedy provider paying AT&T (or whoever) for fiber to the cell phone tower, they'd use the satellite service.
Except... they didn't have an allocation for their ground network. Hmm. What if we reuse the satellite freqs, yeah that'll work. Well, except that the would ruin/destroy/eliminate the possibility of anyone on the ground hearing the satellites without a huge dish or technically impossible filtering. OK no problemo we'll dump all our satellite customers and focus on the ground guys, and use the marketing for satellite "as if" we're not a ground 3G provider. Whoops that'll kill all the adjacent satellite services too. Oh Oh, GPS is adjacent.
Well, so much for that bad idea.
Note there is no reason that instead of paying AT&T for fiber to a cell tower in the middle of nowhere, LS can't provide slow and high latency service RIGHT NOW to that cell tower... this FCC bar only stops them from setting up their own tower and using the satellite freqs to set up something like a 3G service.
The standard /. car analogy is this is kind of like getting rid of the SUV exception where hyper obese ultra low MPG passenger cars are permitted under the legal fiction they are classified as trucks not cars. That takes care of the analogy "why the F are they installing 100 watt ground transmitters on an allocation for satellite transmitters only?". Or maybe a better analogy is LS thought it would be fun to build a network of hydrogen fueling stations, and figured no one would have any problem if they used an off the shelf gasoline filling nozzle instead of a technically correct solution that would not result in an infinite number of burnout fires. That takes care of the analogy "why the F are they installing 100 watt ground transmitters right next to satellite receivers and even daydreaming that won't knock out the receivers".
Don't screw with the big telcoms (Score:1)
Wasn't one of the stated goals of Lightsquared to help little companies compete with the big telcoms on the wireless broadband and mobile phone service fronts? If that's the case, I suspect way more was involved here than just GPS interference.
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Big telcoms? They are puny compared to who Lightsquared was really pissing off. Lightsquared was screwing with the primary user of GPS, which is the USAF, which has an arsenal of nuclear weapons. I think they are somewhat scarier (and more important) than Sprint.
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It's too bad (Score:1)
We do need to utilize these spectrums.
I think what we have here is another example of why business and politics don't mix. Falcone tried to shmooze his way through the system by budding up to the administration and it backfired by creating enemies.
I don't know if his tech is causing a problem or if it's all a big conspiracy to shut him down. It doesn't matter. He assumed he would pass inspection before the fact because he knew all the right people. He had made no preparation for rejection and that was stupi
LightSquared isn't the victim! (Score:5, Insightful)
The article seems to gloss over the most critical point that breaks this deal, painting LightSquared as a victim in the process:
LightSquared's spectrum (which was bought from another company) was for SATELLITE transmissions, not TERRESTRIAL.
Satellite spectrums are much cheaper, but can't be used for terrestrial transmissions.
LightSquared is in fact trying to cheap out by using a cheaper spectrum.
Analogy:
LightSquared tried to buy a plot of cheap residential land to start a chemical/manufacturing plant, which affects nearby residents.
They should have bought a piece of commercial land that supports their requirements.
More technically:
Satellite signals are weak as they are sent from huge distances from satellites with limited power. To receive these signals, the receivers must be tuned to be sensitive to these signals. If LightSquare were to transmit terrestrially from the bordering spectrum (to pass through walls and what-have-you), the transmitted strength will be thousands of times stronger than the GPS signals, invariably causing interference with GPS signals. Even if GPSes are built with a filter (which they shouldn't need to, the nearby spectrums should also be weak signals!), it would be prohibitively expensive/unfeasible to filter the strong terrestrial signals.
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Analogy:
LightSquared tried to buy a plot of cheap residential land to start a chemical/manufacturing plant, which affects nearby residents.
They should have bought a piece of commercial land that supports their requirements.
/. car analogy: They bought property zoned for slot car racing tracks surrounded by residential. Then they said, forget this slot car stuff I'm building a full scale 1000 horsepower indy car / f1 / nascar track and they line up billions of bucks of investment for viewer stands, pork rind fryers, and network broadcast contracts. Then add a dose of blame the victim, those residents complaining about the full size race track being installed in a slot car zoned property should have known better when they mov
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It's close to my lunch time, can I hear from Pizza Analogy Guy?
LightSquared will be ready with their WiFi (Score:1)
Lightsquared vs ATT, Verizon, Sprint.... (Score:2)
Cellphones also use GPS signals to triangulate their position on earth, so that they can connect to the nearest tower with minimal power. This is more FCC doing its real job, protecting everyone from this interference shit.
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GPS is used to keep time in everything from ATMs to our power grid to consumer "atomic" clocks.
WTF? WWV [wikipedia.org]
And why the hell would ATMs need a radio signal to keep time?
I am so facepalmed from that completely wrong statement that I'm going to need surgery to remove my hand from my face.
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Nothing uses your silly 1950s technology, since shortwave receivers are vastly more expensive than GPS receivers due to economy of scale, and also less accurate. Welcome to the 21st century.
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So... change the band. (Score:2)
If the currently allocated bandwidth has proven to cause interference to other services, pick a different band of frequencies to use. They'll have to modify their equipment and I'm sure that will be expensive but if they have the capital to do it, I wouldn't rule them dead just yet.
The problem is the band, not the equipment (Score:3)
The equipment design is the easy part; the problem is spectrum scarcity. LightSquared bought up a bunch of cheap satellite spectrum with the idea of using it for a vastly more valuable terrestrial network. While they DO have the capital to change their equipment to use a different band, they DON'T have the capital to actually purchase that band.
Queue the Lightspeed Defenders (Score:5, Insightful)
Does it appear to anyone else that at least half the Lightspeed defenders must be paid shills for the company? Think about it -- GPS has been around for 20+ years and is considered a utility now, the facts of Lightspeed's purchase of the spectrum (only intended for satellite use) are not in question, and neither is the physics of humongously strong signals next to a band where the signals are below the noise floor. And, who gets all excited about some company's spectrum license unless have a vested interest -- it's not usually of much general interest. I'd like to be proved wrong so I can continue to trust he integrity of sites like /. but I'd say , "Reader beware".
Re:Correction Queue the Lightsquared Defenders (Score:2)
Doh, where is the /. edit or delete function? Anyway, yes I meant, "Lightsquared". And I realize that this is sort of an ad hominem attack which is not what I really meant either, but my basic question remains.
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neither is the physics of humongously strong signals next to a band where the signals are below the noise floor
Sometimes Slashdotters only see the technical arguments. Lightsquared has a somewhat-valid technical argument - if GPS receivers are intended to work on only one band they should take precautionary measures to reject potential interference from neighboring bands.
But, this was never a problem before, so nobody who makes civilian GPS receivers bothered to do so (I presume milspec receivers have dece
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Sometimes Slashdotters only see the technical arguments. Lightsquared has a somewhat-valid technical argument - if GPS receivers are intended to work on only one band they should take precautionary measures to reject potential interference from neighboring bands.
That's not really a valid technical argument. The GPS receivers can very well reject the adjacent bands of relatively equal or slightly greater signal levels. LightSquared is essentially turning the technical details upside down by trying to use the band liscensed for non-terrstrial use for terrestial use.
But, this was never a problem before, so nobody who makes civilian GPS receivers bothered to do so (I presume milspec receivers have decent filters).
LightSquared interferance will actually have more impact on high precision devices. Those high precision devices need their high precision. Additional filtering for better sideband rejection can result in
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Except that if you add the filtering to GPS receivers so they can reject that billions of times stronger Lightsquared signal in the adjacent band, there would be no GPS in your phone. In fact no handheld GPS receivers. Not to mention turning most of the installed base of GPS receivers into doorstops.
The whole point is that satellite signals are really weak, so we put all the satellite frequencies together and keep terrestrial broadcasters out. That's also why satellite frequencies are cheaper than terrestri
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add the filtering to GPS receivers so they can reject that billions of times stronger Lightsquared signal in the adjacent band, there would be no GPS in your phone
So, it's not possible to filter out signals that narrowly? Or does some of the 'adjacent' RF inevitably leak over into the GPS bands?
Interference Deniers (Score:2)
,quote>LightSquared, naturally, continues to deny that the interference is real.
Cue the Interference Deniers in 3...2...1...
Bribery wins again in the FCC (Score:2)
Anyone who threatens incumbent telecoms will be demonized as puppy kickers and grandmother harassers, guaranteed.
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LightSquared would NOT get approvals to operate because they tried to surreptitiously repurpose satellite spectrum for much, much higher powered ground-based systems, thus causing interference all over adjacent low-powered satellite bands.
Yet another case of too politically-connected to fail without a crapload of useless noise.
-ted
FTFY.
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Amen to that.
For national security reasons though, LS must fail.
At least in its bid to use the spectrum. National security trumps everything else. The question is whether LS should be the one to pay for it.
Fail. Just fail. (Score:5, Insightful)
Let's rewind back to the year 2000.
You're a hardware engineer. You've been tasked with building a GPS front end in a cost-effective manner.
You decide to do your homework. You look up the FCC regulations for adjacent frequency bands. Since very high power terrestrial transmissions were prohibited by federal law (i.e. punishable by pound-me-in-the-ass federal prison time for violations), you run the calculations and decide how many -dB/octave your front-end filter needs to exclude signals that you could expect in real world applications.
Sure, you could have gone with a filter that had 2x or 3x steeper roll-off. But why? Your manager asked you to do this in a cost-effective manner, and it's patently illegal for such strong signals to exist.
So you're telling me that a hardware engineer who does his homework and designs a filter that can remove signals which are the maximum legal power is "shoddy"?
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In a just world, LightSquared would be refused the use of this spectrum for terrestrial communications, as it has always been regulated.
LightSquared wants to change the regulations? Great, let them pay for ameliorating the IMPACT of those changes. Namely, let them design a GPS receiver that operates properly with a high-power terrestrial signal interfering with the GPS spectrum, and manufacture & distribute - free of charge to everybody who has a GPS receiver that is "shoddily" designed. And by "shod
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Whats interesting here is that this part of the spectrum has been licensed to them (and presumably paid for), yet is unusable because up to 75% of GPS receivers, that use frequencies just up the range, next door to Lightsquared's spectrum, have insufficient adjacent channel rejection and will be jammed. This is not a problem of Lightsquared's making, it's because the GPS's have been built to poor design standards and allowed onto the market and into circulation.
So if I tell you that we're going to play hockey and you bring proper protection then I shoot you with a shotgun it's your fault for not bringing a bulletproof vest?
Those frequencies were supposed to be for satellite transmissions, GPS worked perfectly fine under that assumption. Lightsquared would have paid a lot more for frequencies that were allocated for ground transmissions. They didn't. They tried to cheat the system and rightfully got burned.
Furthermore as others have pointed out there's a physical l
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GPS signal are so weak they are below the noise floor. I dont know about you, but that just boggles my mind.
Even with quiet adjacent bands - within the origonal intension of the satellite spectrum allocation - the electronics engineers have a difficult job designing a circuit to process these signals. To then add nearby terrestrial interference that is thousands of times larger is just absurd, the size and expense of the filter required to handle this is impractical to build into most devices.
MOD PARENT UP (Score:2)
"GPS signal are so weak they are below the noise floor. I dont know about you, but that just boggles my mind."
Hooray! Someone who gets it!
Yes, you are being dim. (Score:5, Insightful)
GPS was around way before LightSquared's current plan.
Lightsquared doesn't want to set up a new SatPhone service. They want to use their satellite spectrum for ground-to-ground stations instead. GPS was using their own satellite spectrum LONG before LS decided they wanted to use adjacent spectrum for vastly more powerful (read: interfering) ground service. If all LightSquared wanted to do was set up a SatPhone service, then we would quite correctly be heaping scorn on cheap GPS makers...
It's not "shitty design" when a GPS cannot block out a tidal wave of signal from an adjacent band, when that band was only supposed to contain a garden-hose sized signal. Yes, equipment must "accept any interference", but not if that interference vastly more powerful than the spectrum was originally supposed to deal with.
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The FCC rules you refer to do not mean what you think they do. First and foremost, they only apply to TRANSMITTERS operating in UNLICENSED bands. 'Must accept any interference' means that you have no REGULATORY protection if your unlicensed transmissions are interfered with. Even the 'must not cause interference' is not a technical requirement (the technical considerations are handled elsewhere), but rather means that if you are interfering with LICENSED transmissions you must stop using the device, eve
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Hi, I'm one of the people who was involved in the testing of GPS equipment for PNT EXCOM. GPS is a unique form of radio communication, and you cannot apply the same principles you would for a conventional radio to GPS. I highly suggest reading up on how GPS actually works (its pretty darn impressive) because I think with your background, fully informed, you'll understand the problem.
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I'll have a look... though I'm not sure how a system that operates below the noise floor is expected to work (am I being dim again?).