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Wireless Transmissions are Tripping over Each Other as the Airwaves get more Crowded
In the13,000-square-mile chunk of Virginia and West Virginia known as the Quiet Zone, technicians are at work every day tracking down and shutting down any electronic gadget emitting a signal that might interfere with the Zone’s supersensitive astronomical observation equipment. It’s a unique place, but the problem they’re dealing with is one we’re all increasingly sharing: too much electromagnetic traffic.
The radio spectrum – the electromagnetic real estate across which travel the signals for your TV shows, cell phone calls and even garage door opener - is increasingly crowded. There's a finite amount of spectrum but a seemingly endless parade of new devices using it. The number of cell phone users in the US has more than doubled since 2000 to some 200 million today. And a whole army of other less obvious devices is also taking up space in the ether, from hospital X-rays to GPS systems to wildlife tracking collars.
All of that traffic is causing congestion and accidents, as signals jostle for space in their bands and spill over into those reserved for other gadgets. That’s why a neighbor’s call sometimes gets broadcast over your baby monitor or your cordless phone trips up your Wi-Fi connection. But the consequences can be more serious. Radar detectors used by truckers have disrupted gas station credit-card authorization systems. Broadcasts from a Dallas-based digital TV station scrambled signals to wireless heart monitors at a nearby university. And a baby monitor tripped up communications among air-traffic controllers at London’s Luton Airport.
Spectrum shortage is even a problem in Iraq, where the US military relies on a dizzying array of wirelessly connected technologies. Jammers designed to disable improvised explosive devices have interfered with communication from unmanned aerial vehicles and with ground-based radio.
All of this, of course, is set to only get worse as ever-more wireless technologies come into ever-heavier use. Which is why scientists and industry researchers are beavering away at several possible technological fixes.
One approach is “ultra-wideband” technology, which spreads an electromagnetic signal out across a wide band of frequencies at low power, rather than jamming one high-powered wave through a narrow band. Or there’s “mesh networking”, a system in which each device that receives a signal – a laptop, a radio, whatever – also retransmits it. That would allow signals to be sent at much lower power, since the distances they would have to travel would be much shorter.
Another potential solution getting significant buzz is “cognitive radios”, which would come equipped with software that would enable them to skip around the spectrum to find bands without much traffic to transmit over, and to pick out only the desired signal from incoming noise. Bluetooth devices may eventually be able to perform a similar trick, sensing Wi-Fi signals in the area and broadcasting around them.
Such unused bits of spectrum – “white spaces,” as they’re called – have also sparked a high-stakes battle in Washington DC. A coalition of technology companies including the likes of Microsoft, Google and Intel is lobbying the FCC to allow the unused spectrum between television channels to provide other services, such as Internet access. Broadcasters are fighting back, saying that allowing things like wireless devices into their reserved spectrum bands will interfere with their transmissions. The tech side counters that a new generation of devices will be smart enough to avoid frequencies carrying TV transmissions. The Federal Communications Commission is expected to make a decision soon – hopefully before the next spectrum traffic jam.
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12.26.07 6:34 PM PST
gonca
my friend Jeanie is in to protecting people from the magentic rays from electronis objects. And has eduacted me and alreted me to the importance of keeping myself safe.
12.26.07 11:28 PM PST
Bill in Sandy Eggo
A wonderful solution would seem to be, to limit the maximum effective coverage of all transmitting devices to just, say, 5 or 10 miles.
There would have to be retransmitters in the actual desired coverage area, to get the intended coverage, but interference could be drastically curtailed.
Only military and specific government organizations could exceed that limit, to do their jobs.
12.27.07 8:39 AM PST
GJ
Bill - so you would eliminate all commerical radio and television transmissions, not to mention amateur radio, which, by international law, uses frequencies anywhere from a few kiloHertz to laser light with legal power levels capable of communicating over great distances? I don't think you've thought that through completely...only the government and the military , eh? NOT! Perhaps you should talk to Katrina and tsunami survivors whose only assistance came, not from government or military communications, but rather via amateur "ham" radio. The quiet zone around the WV facility is an anomaly. It's an exception to the rule, allowed by gentleman's agreements more than anything else, to help advance the state of interstellar research. And "gonca" - there are no "magentic rays" from "electronis objects." Radio Frequency signals have been known to cause heating of tissue and, for this reason, are used in medical research and treating (as well as a power source for fusion research). There are well-known regulations regarding distance from antenna to subject. What most people fail to remember is "the inverse square law is your friend!"
Pretty much everything you and I know about radio waves and their uses was invented by radio amateurs throughout the past 100+ years, including radio astronomy!
You would be better off being "eduacted" in gud spelling than worrying about nonsense your friend Jeanie tells you!
12.27.07 9:46 AM PST
Tim L. Marshall
Loved this segment; what a beutiful area to live. But I could never give up my many electronic hobbies to live there! When ever "Wired Science" is on - it is a much watch! I'd love to work there.
Also loved the other segments and would love to live in the Energy Prefab house you showed. I am a totally and permanently disabled veteran still trying to get out from under the damages of three hurricanes (Jeanne, Francis, & Wilma) that scored a direct hit on my area. I hope this modular concept embraces weather resistance models too!
Keep-up the great work at "Wired Science"!
1.25.08 7:41 AM PST
Bruce in Dallas
"Radar detectors used by truckers have disrupted gas station credit-card authorization systems" . Detectors, listen, they do not emit. How could it possibly electronically disrupt the credit card system?
"Broadcasts from a Dallas-based digital TV station scrambled signals to wireless heart monitors at a nearby university." The story I remember hearing was it was a bluetooth headset in use by a parent ,who irresponibly was using it in a newborn nursery at a local hospital. That nursery had signs everywhere telling people not to use such items becasue of known wireless network interference problems with medical monitoring equipment.
1.30.08 9:57 AM PST
mark balkan
I was giving my students extra credit for watching you show....but I don't know if you are on our PBS station any longer...what happen? the show is great and very entertaining? It was on at 8PM on Wed. nights
6.25.08 10:02 AM PDT
mujeetha
please keep traffic signals and their uses one by one in short forms and in a neat way.It should be in a way that,we can copy it by drawing by our own hand also.Iam not at all satisfied with your makings and settings.Please take some steps according to my comments,please.
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