WirelessCabin: Use Your Mobile Phone on Airplanes

securitas writes "What if didn't have to turn off your mobile phone when you travel by air? eWEEK's Matthew Broersma reports on a European Commission project to enable mobile phone use on airplanes. The technology works by creating short-range 'picocells' that force transmission output power to drop to 1/1000th of normal, reducing electronic interference, then using a satellite uplink. The WirelessCabin project members include the German Aerospace Centre, Siemens, Ericsson and Airbus. Initial trials will use 'GSM, Wi-Fi and Bluetooth connections' but will add CDMA and 3G standards. WirelessCabin is already making a picocell with CDMA2000. The first demonstrations are scheduled for this summer on Lufthansa long-haul flights with the A340-600 jet."

So you'd rather...

[lxt]

...a plane crashed to prove it?

There's lots of evidence that phones can interfere with navigation equipment, and from my experience as an audio engineer I can tell you digital cell phones can very easily intefere with electrical equipment, disrupting signals etc.

Re:Too complicated

[cmdr_beeftaco]

One word, incoming telephone calls.

Re:The whole no phones in planes

[LostCluster]

Nope... there's two bans on phones in flight...

- The FAA doesn't like them because of the longshot theory that radio waves of any kind might just add up to a signal that tricks autopilot or other navigational systems into glitching, causing the plane to crash. That's a long shot risk, but the disaster case is kinda a bad one if it ever happens.

- The FCC also has a ban because when you're in flight, you're always at least 6-8 miles away from the nearest cell tower. You end up communicating with too many towers and bogging down the network. One or two such calls is tolerable, but a whole plane load moving through would disrupt the ground-based users of the network.

This picocell concept solves both problems by moving the nearest cell tower to just a few feet away from the phone. Therefore, the phone kicks into its lowest power setting, and never talks to any other tower.

Re:The whole no phones in planes

[LordDartan]

I've been a pilot for 15 years now and I can tell you without a doubt that cellphones (and most any electronic device) can affect instruments in the airplane. Yes, in this day and age the chances of that have been reduced, but it can still happen.

Re:Sky high rates?

[adam mcmaster]

Do cell phones actually interfere with airliners anyway? I mean c'mon -- are the systems onboard a modern aircraft really so fragile that my cell phone will bother them?

There's an article [wired.com] in this month's Wired that talks about this. Basically, no it wouldn't cause a problem.

Re:Sky high rates?

[stephanruby]

Do cell phones actually interfere with airliners anyway?

No, they interfere with cell towers, that's the problem. The plane is going so fast that the cell phone keeps on switching towers.

Re:Sky high rates?

[goates]

You can also be in range of more than one or two towers at a time as well. Either way, the cell networks have trouble with it.

goates

Interference?

[bsd4me]

There was an article in IEEE Spectrum [ieee.org] about this a few years ago. I would post the results, but (1) I forget what the article said, and (b) I am lazy.

Re:Sky high rates?

[sir_cello]

I wish I could remember the reference, but I read recently that supposedly the main issue with mobile phones on flights is the way they splatter themselves across cells on the ground. The article acknowledged that there have been many examples of people accidently leaving phones on during flights.

Personally, I've left a GSM phone on during a flight once.

Additionally, as an engineer, I would be _extremely_ suprised if the GSM standards bodies and the FCC/licensing authorities actually permitted the GSM technology to be made available to the public if there were any chance that it would interfere with navigation systems or any other critical systems (medical equivalent). We would have a string of news articles about plane crashes if this were the case. This simply doesn't happen for massively deployed technologies because it goes through all of these regulatory hurdles. I guess you could have an issue with equipment from other less rigorous countries, which may be the main point.

Equally, I've accidently travelled on a post 9/11 cross-european flight with a pocketknife keyring. I realised when I was in the air that it was in my carry on "man bag": this was after I waited one hour at Stansted to make my way through supposedly tight security. I wanted to take an in-flight photograph to prove it, yet worried that attendant would see me and I'd be meeting the boys in blue at the other end.

Re:I never turn it off

[radish]

Please wear a badge so I can avoid going on a plane with you.

Most of the civil aviation regulators of the world ban cellphones on flights, I really don't believe that they do so simply to make the network operators happy. There has been at least one crash (a CrossAir flight in Switzerland) which the official report blamed on a cellphone, and there is at least one post on this very thread from a pilot who says it is a real problem. But you know more than all of them right?

Electromagnetic Interference is a real phenomenon

[Anonymous Coward]

Howstuffworks: I've noticed that I am not allowed to use my cell phone in airplanes or in hospitals. Why are these prohibitions in place? [howstuffworks.com]

ELECTROMAGNETIC INTERFERENCE [airnig.co.uk]

Electromagnetic Interference with Aircraft Systems: why worry? [uni-bielefeld.de]

Re:Sky high rates?

[Anonymous Coward]

Broadcasting from a plane is bad from a network point of view because you light up sveral hundred cells at a time. Since you are above them with clear line of sight your signal travels much farther than normal. Most of the time is traveld further than the frequency reuse distance, meaning that you just trashed the capacity of the cellular system.

And yes, it is possible for Cell phones to affect accuracy of onboard instuments in older planes... There is NO GROUND PLANE on an aircraft. You are sitting a nice big faraday cage... so the onlything to absorb your signal is the equipment around you.

From a practical standpoint I would prefer rules that ban Cells on aircraft for comfort reasons... an aircraft is close personal quarters... I really don't want to hear your conversation on a long flight... (AIRRAGE!)

You can already use your phone

[Anonymous Coward]

Many new phones have a "flight mode", where you can still take notes, play games, etc. But you can't send SMS or make phone calls.

Re:Is the danger real?

[cheide]

There is certainly a potential for interference. Electromagnetic compatibility isn't always a straightforward matter; I briefly worked on a software tool to assist in compatibility testing and there are a *huge* number of ways signals from different components in an aircraft can combine and interfere with others. You can't just certify a range of frequencies as being okay and leave it at that, because it also depends on how the frequencies are generated inside the device, which may be different from device to device. Any time a new frequency-generating device was to be added to a plane, it had to undergo fairly extensive testing first.

One case that they were investigating involved a jet that was fitted with extra sensors and transmitters to gather vibration data. After taking off and reaching level flight, the pilot turned on the sensors, only to have the entire avionics system immediately shut down. It took a while before they finally figured out what had happened -- the sensor packages were transmitting on the resonant frequency of a length of metal in the plane, which acted as an antenna and leaked energy into the nearby circuit breaker, which then tripped.

I'm not sure how well this relates to cell phones since these were fairly high-power devices and I'm not familiar with cell phones, but for what it's worth...

Re:Is the danger real?

[kc8tbe]

The situation isn't really dangerous. In fact, HAM radio operators are allowed to use their radios during flight (just not during take off and landing). The problem isn't in interference with avionic equipment but rather, as has already been mentioned, in the cell network.

Normally several adjacent towers pick up your signal, and then decide which one has the best signal quality. That tower then handles the signal. Remember, signal quality/strength is best with a line-of-sight to the cell tower. Well, on an airplane, you have line of site to lots of cell towers - some of which are several miles apart and consequently not programmed to defer your signal. Too many users doing this could crash the cell phone network!

Perhaps a more effective solution would be better tracking software in cell towers. Software that enabled far-away towers to communicate and defer your signal would resolve the problem and be a whole lot cheaper than using sattelite uplinks.

Re:Sky high rates?

[jjhall]

Yep. Periodic handshakes going on between your phone and the cell network.

Cell1: Hey, Bob's phone, are you still there.
Phone: Yeppers. Read you loud and clear.
Cell2: Can you hear me?
Phone: Yes, I hear you too.
Cell2: OK, just wanted to make sure.
Phone: Just send me a call if it comes in.
Cell1: Roger.
Cell2: Ditto.

Obviously that is not the technical terms for what is going on, but it seemed a little more humerous.

The importance of this is when you call someone whose phone is turned off, a lot of times it will say "Please wait while the (insert carrier name here) subscriber you have dialed is located." If the phone just went through the handshake, then the network thinks it is still there. It will try several times to find it if not. After 10 seconds or so it will go to voice mail. If the phone has been off during several handshakes, the network knows it can't complete the call and it goes right to voicemail. If you are traveling at a high speed through an area with high cell density, you can actually move between several towers between the handshakes, and that will cause the delays as well before being connected.

This is also the reason paranoid people don't keep their phones on. The network knows the general location of every cell phone user at most any given time.

I know for a fact that TDMA and GSM with AT&T, as well as iDen with Nextel, and CDMA with Verizon all exhibit the periodic handshake with the associated interference. Since T-Mobile and AT&T use the same GSM network band, there is no difference between the two. Now if only they would establish a roaming agreement with each other...

Jeremy