In Florida, a Cell Phone Network With No Need For a Spectrum License 107
holy_calamity writes "Technology Review reports on a cell phone network in Fort Lauderdale, Florida, like no other. Instead of paying to reserve a section of wireless spectrum its owner, xG Technology, uses cognitive radios that steer signals through the unlicensed 900MHz band more normally used by cordless phones and baby monitors. The radios in both handset and base station scan for gaps left by other devices in that band and make dynamic connections that constantly hop frequencies to ensure a good link. The network is designed to show off the tech, which the company says could be used in conventional cellphones to access extra spectrum or white spaces devices."
So what's the range (Score:4, Funny)
and does it use a lot of "femto-cell" style towers? It would seemingly have to. Meaning, how well would it work in a car?
Re:So what's the range (Score:4, Informative)
900Mhz is the most popular GSM band in Europe and most of the rest of the world. My mobile operator uses it, and it works very well in my car. I guess that means it would be illegal to use this phone in most parts of the world.
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The 900Mhz ISM band is free to use in region 2 (the Americas, Greenland, and part of the Pacific Islands).
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Maybe I wasn't explicit enough, or maybe it's local colloquialism rearing it's ugly head again.
In the States the most popular cordless handset in a home in the 90's was the 900MHz band variety. They had a further range than most other cordless handsets at the time, allowing you to make it as far as a large backyard with no problem.
Thus the connotation is that it would have a range as far as your home.
It isn't going to work (Score:5, Interesting)
It's never going to work in the long term. I work for a wireless ISP, and our 900 mhz band is getting killed by utility/electriticy companies rolling out things like smart electric meters that exist in every home and do the same thing: hunt for the least noisy band and transmit. We've seen noise floors in the -40s straight across the spectrum on our worse days. We can't beat the noise more than a couple of miles from a cell tower using fixed, directional antennas. What makes them think they can beat it with tiny, handheld devices?
Re:It isn't going to work (Score:4, Funny)
br>Also, why am I now being forced to preview? Maybe I like making errors.
Re:It isn't going to work (Score:5, Informative)
They changed the name of a pref from 'Use Classic' to 'Dynamic Discussion', defaulted it to 'yes' and made it so that it can only be accessed (as far as I have found) from the prefs that pop up with the button on the bottom of the comments pages.
Re:It isn't going to work (Score:5, Insightful)
Thank you. Finally restored the old, crappy, but understood format. I wish Slashdot would spend less time writing code, and more time reading and editing articles if they really want to improve the site. I'm just hanging by a thread as it is.
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Yeah me too, was considering just giving up on slashdot. The dynamic discussion is a big nono.
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FUCKING SAMZENPUS - DON'T *EVER* LET ME FIND OUT WHERE YOU LIVE, ASSHOLE. I WILL RIP YOU A NEW ASSHOLE FOR YOUR BULLSHIT.
You're a big fucking idiot for posting anything like this, anywhere, ever. Calm down, have some dip.
Lameness filter encountereLameness filLameness filter encountered. Post aborted!
Filter error: Don't use so many caps. It's like YELLING.
ter encountered. Post aborted!
Filter error: Don't use sLameness filter encountered. Post aborted!
Filter error: Don't use so many caps. It's like YELLING.
o many caps. It'Lameness filter encountered. Post aborted!
Filter error: Don't use so many caps. It's like YELLING.
s like YE
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Don't use so many caps. It's like YELLING.
I think he understood that. My guess is it that it was intentional. Duh. Sometimes, screaming is appropriate, particularly when talking about the progressive decline in quality here lately.
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Don't use so many caps. It's like YELLING.
I think he understood that. My guess is it that it was intentional. Duh. Sometimes, screaming is appropriate, particularly when talking about the progressive decline in quality here lately.
I was pasting the output from the lame filter, noob. Who did you buy that UID from?
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The lameness filter said "You're a big fucking idiot for posting anything like this, anywhere, ever. Calm down, have some dip." ?
Oh, I didn't think so.
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No, but it did tell me you're a big douche. When people encounter the filter it's common to throw the text of the filter back at it. And you didn't quote the other part, so I was responding to the part which was quoted. Hope this helps you understand why you're a douche.
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Did you get the ability to disable ads on slashdot, yet, like I have?
Because that's my punishment for them until they start fucking proofreading and editing their stories.
Yes, and me too. I used to allow them to display as well, but don't now for the same reasons.
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Thank you so much. I had some points the other day and thought I was mis-marking posts or something because my points disappeared when I scored a post but I never hit "moderate."
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Bless you.
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Also, why am I now being forced to preview? Maybe I like making errors.
Slashdot wasn't losing users at a fast enough rate, so this is part of a new program to piss those of us off that have been here for many years, and get us to finally leave forever. It is about to work.
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Give it two more weeks, and we won't even be able to /. this website [120.146.162.194].
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Re:It isn't going to work (Score:5, Informative)
The ISP I worked for (and managed the network operations of) mucked around with 900mhz band proprietary WiFi and it was, for the most part, a total disaster. The worst came when the guy whose apartment was immediately below our antenna went out and got some sort of 900mhz cordless phone that just splattered horribly over that area of spectrum, taking everything down with it. My boss literally went out and bought the guy a 2.4ghz phone just to stop it. Then the pager tower near one of our other antennas went crazy and started spewing forth over that bit of spectrum too.
We were told by the supplier that their equipment could pick the holes in the 900mhz unlicensed band, but so far as I could tell, anything beyond fairly mild interference just made the whole system highly unreliable. Hell, the last 900mhz cordless phone I bought when we were stilling living in an apartment was constantly picking up other phone calls.
I didn't know dick about radio at the time, but asked my boss why weren't going with 802.11b (which had just become available not to long before, and was up in the 2.4ghz range and had a growing number of WiFi devices that could talk to it, meaning we didn't have to rent out custom WiFi units to our customers). He liked the proprietary stuff because it was more secure (true enough, from an obscurity point of view, though I don't think it was encrypted) and because he wasn't relying on the 802.11 access control methods (though he had no problem with a Radius server for our dialups).
The 900mhz bands are just to bloody dirty and too congested.
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Also because of the interference problem, IIRC it was ruled that a commercial operator cannot use the ISM bands for a cell network in Canada. This is not the first time its been tried.
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"IIRC it was ruled that a commercial operator cannot use the ISM bands for a cell network in Canada.'
IIRC as well you can't even run in that band without severely limiting the transmitting power of the device.
A decade ago, when I was in Quebec, the 900 MHz phones sucked not even a room away from the base station.
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A decade ago, when I was in Quebec, the 900 MHz phones sucked not even a room away from the base station.
Whats ironic is that the original selling point of 9800Mhz cordless phones was less interference compared to the 47Mhz phones. Then an arms race started with 2.4Ghz and later 5.7Ghz phones.
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One of the main problems with 802.11 for wide-area use is that it's a version of csma; a radio will listen for an open spot, then transmit when thinks it's quiet. Now, locally, that's usually fine. But for wide-area issues, consider this: base station A sees radios B and C. Radio B doesn't hear radio C; they're twelve miles apart, on opposite sides of the base station. Therefore, radio B and C talk over one another.
You need some sort of polling mechanism where the client radios only talk when the base i
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Collision Avoidance, in this case, means they listen for open air. Collision Detection means they talk, and back off if there's a problem. This also makes it difficult to do QoS at the radio level.
http://en.wikipedia.org/wiki/Hidden_node_problem [wikipedia.org]
http://en.wikipedia.org/wiki/Carrier_sense_multiple_access_with_collision_avoidance [wikipedia.org]
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Oh, and self reply, RTS/CTS doesn't quite make it compared to a proper polling system or TDMA. You also can't do any sort of base station syncronization with an 802.11 style setup.
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We found the shot worked, until it rained, and those frickin' rain drops in leaves and such caused major multipath problems. I know some of the newer equipment can deal with that, but still, it's only one of many problems with the 900mhz band.
Not all 900MHz data transceivers are created equal (Score:2, Informative)
Try GE MDS Mercury 900MHz systems. We're getting between around 300-500Kbps average up and down between moving vehicles and the nearest access points almost anywhere in the whole city. Fixed locations such as traffic light controllers with small yagi antennas pointed back to an access point tower site easily hit 900-1000kbps symmetrical bandwidth up and down.
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Came in here to mention this. I worked for a WISP a couple of years ago, and while it was in a rural area in Kansas (but i repeat myself) we were already aware of possible issues with public spectrum transmissions and signal-hopping competition from god only knows what. We had a 900mhz unit in town, aimed at an AP on the other side of town with a clear LOS (i dont know why they did this is town, it happened before I was there) and we couldnt get it to work for our life. We had a spectrum analyzer and couldn
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I think in a rural setting, particularly a relatively flat setting, 900mhz would probably work. Certainly our time with 900mhz WiFi suggested that where we could get a good run over sparsely populated areas, the signal would carry very well, but yeah, we found that the town itself just has a bazillion sources of interference at and around those bands.
I actually wish I had a couple of those 900mhz transmitters now. I own some acreage with two houses, one about fifty feet above the other and a couple of goo
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"We had a 900mhz unit in town, aimed at an AP on the other side of town with a clear LOS (i dont know why they did this is town, it happened before I was there) and we couldnt get it to work for our life. We had a spectrum analyzer and couldnt even get a lock on what was causing the issue."
HPS and fluorescent magnetic ballasts, most likely. Not very much else typically causes spikes in that range out in the wide open. Malfunctioning magnetic ballasts destroyed cell and cordless capability at an old apartmen
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Hello football game (Score:2)
(zap)
Goodbye football game. I can easily imagine this device broadcasting directly over long-distance channel 17 while I'm trying to watch the game (or movie or Glee or whatever). The device will think the channel is "free" because it cannot detect it, and start broadcasting on 17, but in reality it will be occupied.
.
>>>Feedback on this comment system?
Yeah it sucks. And it's slow (CPU intensive). And I can't get back to the classic (plain text) index even though I've un-checked and checked it m
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Click the pencil/paper icon on the right hand side of the bar above the first comment. There's a pref for the old system.
Took me about 15 minutes to find it, since it wasn't in my user prefs.
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It's working for me in Firefox 3.6.11 on windows XP.
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I wouldn't bother posting this but I assume others are "suffering" too. Maybe if they click "5 more messages" a few hundred times they'll see this.
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/. won't go back to the old system totally.
Hey, if you want the site stable, tell the nimrods to move to something more stable and less likely to get exploited, like the motherfucking standard of the web - HTML.
Or get the rest of the site to tell them to fuck off until they do.
Good luck with either.
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Yeah I *finally* got it fixed by unchecking "dynamic" in the Discussion menu.
Jeez. It should not have defaulted to being turned on.
Or else make it more obvious how to disable it.
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Obviousness is not a strong point of /. programmers or editors.
In fact, given the differences between the systems, I'd suspect /. made this default so they could serve up more advertisement stuff on the fly.
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>>>made this default so they could serve up more advertisement stuff on the fly.
Like Google's instant search. ;-)
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Trolling, or just RTFS fail? Considering it's commodore64_fuck (1445365), it's always hard to tell...
This isn't a white-space device running in "unused" TV channels, it's using unlicensed spectrum, just like bluetooth and wifi. The only other thing in this band is... other unlicensed devices, all talking over top of each other. It ends up a lot like 2.4GHz wifi, of course -- too many people transmit all at once, raising the noise floor, so everyone has to retransmit more, and eventually it becomes practical
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>>>commodore64_fuck
>>>This isn't a white-space device running in "unused" TV channels
Speaking of not being able to read. From the article: "The system could augment emerging networks that operate in the unlicensed 'white spaces' recently freed up by the end of analog TV broadcasts."
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Yes. Like you, I can read.
Apparently unlike you, I know what "augment" means.
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"augment emerging networks that operate in the unlicensed 'white spaces' recently freed up by the end of analog TV broadcasts"
Want to re-read what you quoted? It clearly implies that these networks *ARE* running in unused TV channel-space and that the technology in question will ENHANCE (augment) the capability of those networks to operate in that frequency range by skipping back and forth across detected unused frequencies within that range.
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>>>It clearly implies that these networks *ARE* running in unused TV channel-space
Yes I know.
The AC said 'These devices won't be used in TV band'.
I was refuting that; clearly he's wrong.
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Is the government or industry under some kind of obligation that you receive a distant station? I don't think so. There's an obligation for free television in support of the public interest, but not for any and all stations you could ever pick up from any market with any size or gain antenna.
Come back to us when a local television station is interfered with by these myt
You gotta wonder how much bandwidth is left (Score:2)
You have to wonder, with all of these devices that use the rather spread-thin (no pun intended) "free" spectrum, just how much bandwidth is left in your average area? What with everyone's WiF, cordless phone, microwave, bluetooth, etc. devices running constantly, are we reaching a point where "free" consumer spaces simply need more bandwidth?
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No, we are reaching a point where we need to figure out and list exactly how much bandwidth each given range of frequencies has, then we need to figure out which available devices best fit those ranges, and then restrict them to those ranges and that bandwidth allocation. Let them fight over the subchannels.
From the article . . . (Score:4, Informative)
the system could augment emerging networks that operate in the unlicensed "white spaces" recently freed up by the end of analog TV broadcasts
The only channels "freed up" when US NTSC ended was 52-69 and they've already been designated for Cellular and Emergency Radio usage. These gadgets are verboten from broadcasting in that area.
A recent study by University of California-Berkeley academics revealed how the density of TV stations in metropolitan areas could reduce the availability of white spaces in such areas.
That's true. The "whitespace" idea only works in rural regions, not heavily-populated areas like the North, northeast, or mid-atlantic which use every channel from 1-51 (including the FM band).
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A recent study by University of California-Berkeley academics revealed how the density of TV stations in metropolitan areas could reduce the availability of white spaces in such areas.
That's true. The "whitespace" idea only works in rural regions, not heavily-populated areas like the North, northeast, or mid-atlantic which use every channel from 1-51 (including the FM band).
There are more than 51 channels, there are 68 (2-69).
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Not anymore. Channels 52-69 are no longer in use, not being permitted for TV broadcasters.
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>>>There are more than 51 channels, there are 68 (2-69).
Judas Priest. Can't you read? Quote: "When US NTSC ended was 52-69 and they've already been designated for Cellular and Emergency Radio usage." At one time there USED to be 82 channels (2-83) but everything from 52 up has been deprecated and no longer exist as channels.
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That's true. The "whitespace" idea only works in rural regions, not heavily-populated areas like the North, northeast, or mid-atlantic which use every channel from 1-51 (including the FM band).
Note that Channel 37 is not used for over the air tv broadcasting in North America and the few other uses area very limited (things like low-power indoor hospital equipment. It's being kept very quiet for those listening for interesting things from deep space. The signal that one would get on Earth from a hand-held
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"I'm curious when the FCC is going to figure out that hardly any broadcasters remained on their former analog channels 2 through 6. (54 to 88 MHz, minus a 4 MHz gap between channels 4 and 5)"
Never, because there are at least three separate pirate stations that use that range. It appears as used to the FCC as anybody else.
54.88765 MHz was my favorite back in Memphis. Had to use an OLD multi-range radio with shortwave capability to access it, but that had the BEST indie techno ever. And the Chinese broadcasts
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>>>I'm curious when the FCC is going to figure out that hardly any broadcasters remained on their former analog channels 2 through 6
The FCC knows it.
They were the ones who *recommended* stations avoid 2-6.
Most listened to the FCC but some (like 6 in Philly) did not.
>>>Broadcasters apparently figured few people would be willing to put up big tv antennas with the longer elements needed for those low channels.
They were right unfortunately. I've heard engineers saying their viewers *refuse* t
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"The only channels "freed up" when US NTSC ended was 52-69 and they've already been designated for Cellular and Emergency Radio usage."
Excuse me? I'm getting 53 DTV and 59 DTV on my antenna.
Better re-check what did or did not get taken out *AND* in which areas, pal. Hollywood and Mexico seem to still be broadcasting across ALL the channels you just mentioned. I just turned my TV on to check, and I *JUST* bought a nice non-powered antenna just so I could watch the OTA Korean soap operas.
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>>>>>"The only channels "freed up" when US NTSC ended was 52-69 and they've already been designated for Cellular and Emergency Radio usage."
>>
>>Excuse me? I'm getting 53 DTV and 59 DTV on my antenna. Better re-check what did or did not get taken out *AND* in which areas, pal.
(sigh)
Well "pal" those are virtual channels. I too get channels 57 and 61 and 65 and 69 on my DTV, but the *actual* channels are inside the 2-51 limits imposed by the FCC's post-transition standard. Also yo
NACK (Score:2, Informative)
(I'll stick with my modified 10-meter 1KW CB radio ...)
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If someone in your neighborhood turns-on their portable phone or baby monitor, this experimental device is supposed to instantly "jump" to another free frequency. Due to digital buffering you won't hear any kind of interruption.
I'd like to see the FCC sell-off channels 1-13, which are basically worthless for DTV (too much noise), and use them for cellular internet (which has better error-handling). There's also a large chunk of old analog CB radio that could be reclaimed between channels 6 and 7.
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Given the rise of cell phones, I'm not sure why we don't go back to just 23 channels rather than 40 anyway. Is the CB spectrum really crowded enough to still need 40 channels somewhere?
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"Is the CB spectrum really crowded enough to still need 40 channels somewhere?"
Most of Middle USA, the entirety of the Interstate system, and most major cities with trucking depots (like Memphis, Chicago, Dallas, Houston, Los Angeles, etc.)
Even FRS/GMRS is crowded in those areas. Been there, tested that. FCC is slacking, half of the GMRS band is taken by unregistered/unlicensed people.
Validity Questioned (Score:5, Informative)
Validity of using up bandwidth that way? (Score:2)
Forget the company. I don't want anyone clogging up any unused unlicensed frequencies and causing interference for every other device that does use that space. It's unlicensed for a reason and that reason isn't so some douche can sidestep going through the proper channels to set up as a carrier whilst hosing everyone else's use of those frequencies.
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>>>hosing everyone else's use of those frequencies.
Given recent FCC decisions, I suspect they don't care. After all this agency approved TV Band/whitespace Devices even though they will interfere/block usage of wireless microphones and other A/V equipment. I wouldn't be surprised if they read about this new Florida Experimental cellphone and say, "Approved."
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If the FCC was a local health and safety authority, the approval process would go something like this:
FCC: We see, Mr. Cacapoopoo, that your sewer technology takes raw human waste and dumps into rivers and aquifers.
Mr. Cacapoopoo: Yes, that's correct. My patented OneTube sewer device takes a large pipe from underneath each toilet and then promptly dumps into the nearest reservoir of drinking water.
FCC: And you've tested to make sure that this doesn't cause people to get sick.
Mr. Cacapoopoo: Oh my, yes. Ou
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Translation for those who are confused:
FCC: We see Mr. Representative of Google, Microsoft, Apple, etc, that your TV Band technology takes data and dumps into the television channels.
G,MS,A,etc: Yes, that's correct. My patented device broadcasts over top the 6 megahertz channels currently used by television.
FCC: And you've tested to make sure that this doesn't block people's television.
G,MS,A: Oh my, yes. Our research shows that the human television will be unaffected within 30 miles, and only 1/3 of viewer
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This article [ka9q.net] questions the validity of the company.
That's a great link, thanks for posting, but to be fair, the original TFA is talking about an entirely different topic, the use by xG of cognitive radio ("cog radio") techniques for spectrum utilization, rather than some new, ostensibly power saving modulation scheme developed by xG.
Cog radio still has the potential to alleviate spectral congestion in some situations. It may be very beneficial to some users (i.e.: military) which is why DARPA and some military agencies continue tio fund development of sam
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Let me follow up on my own post (can I give myself mod points?).
Here, xG provides a brief description of their spectrum using tehnique: (basically, look for unused segments):
http://www.xgtechnology.com/Technology/technology.html [xgtechnology.com]
I was unable to find any reference to xG Flash, the modulation scheme debunked by Phil Karn. Here is xG's description of xMax, the modulation system currently used by xG:
http://www.xgtechnology.com/Technology/xmax-physical-layer.html [xgtechnology.com]
which is pretty mundane (for wireless nerds lik
This could be distributed/home grown GSM's break (Score:2)
For now the only decent BTS an 'ordinary' consumer can get their hands on is USRP/OpenBTS which costs around $1000. The idea of normal people running a mobile network has been pretty much suppressed everywhere else so it would be interesting to do some long term real life testing with real users if its perfectly legal so the conc
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>>>The idea of normal people running a mobile network has been pretty much suppressed everywhere else
What do other regions (like EU) use the 900 MHz band for? According to wikipedia the US allocation is only 5 TV channels wide, so not a huge amount of room for data usage.
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We use it for licenced GSM cellphones. In the UK, Telefonica O2 and Vodafhone operate on that band.
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To be clear, in Europe, the 900MHz band is currently used for straight GSM and EDGE. UMTS/WCDMA (GSM 3G) runs on the 1800/2100 MHz band pair. In the USA, the AWS band pair (used by T-Mobile) is a subset of that. It uses the lower half of the 1800MHz for uplink, and the lower half of the 2100MHz band for downlink (which is why it is referred to as the 1700/2100 MHz band pair). T-Mobile uses the 1900MHz band for GSM, but also supports the 850MHz band for roaming, since AT&T uses that band. AT&T's UMTS
kind of an annoying name (Score:3, Insightful)
"Cognitive radio"?
A protocol that continually finds and hops to not-interfered-with frequencies is perhaps "intelligent" in a generic sort of way, but calling it "cognition" is a bit weird. It's pretty standard communications-theory stuff.
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Marketing wank.
Lies, Lies, Lies (Score:3, Informative)
Any for-profit outdoor system (Score:2)
Frequency Hopping and Security (Score:2)
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Somewhat. Frequency hopping was invented to prevent radio-steered torpedoes from being jammed by the enemy.
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Somewhat. Frequency hopping was invented to prevent radio-steered torpedoes from being jammed by the enemy.
http://en.wikipedia.org/wiki/Hedy_Lamarr [wikipedia.org]
Ricochet did this a decade ago (Score:4, Interesting)
Ricochet [qsl.net] did this in the 900MHz band using spread spectrum a decade ago, for wireless Internet access. They put up little nodes on street light poles, using a deal where the municipality got free data access. It worked fine, but only delivered dial-up speeds, so it was overrun by DSL and cable. Even back then, getting around narrowband interference was no big deal.
Does this mean (Score:2)
that Slashdot now needs a "Florida" tag?
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Speaking as someone who lives in Florida, you can feel free to use whatever tag you have similar to "scam" in lieu of a "Florida" tag.
Cognitive radios, eh? (Score:2)
Strap on your tinfoil hats, people, because this time it's the real deal!
Yeah but will it...? (Score:1)
Does this mean later, cell phone co can actually use this technology, and lower their prices, or will they just use this, and still charge us an arm and a leg.......as we ARE the world's most highly charged for cell phone calls in the world.
Not so exciting (Score:2)