RevMan2

The village idiot John Mica - he of the law requiring each seat to be clearly labelled with the aircraft's country of manufacture and also of the proposal for mandatory anti-missile defence systems for - and only for - the A380 - appears to have seen the light:

US: Panel discussing cell phones on planes
(Source : AP, July 14, 2005)


Airline passengers who cringe at the idea of seatmates with cell phones have a friend in the House's top lawmaker on aviation issues. 'The last thing most air passengers want is to be forced to listen to their neighbour chat on their cell phone about their ailments, their dating problems, the latest reality TV show or up-to-the-minute estimates of time of arrival,' says Rep John Mica, chairman of the House Transportation and Infrastructure's subcommittee on aviation.

Hang in there, sunshine. We're right behind you!

Of course, that's just my opinion. I could be wrong. (But I don't think so....)

jewitts

A bit off-subject but an interesting aside nevertheless...
Last week I was delayed for over an hour on a Turkish Airlines plane to Istanbul. After about half an hour the chief flight attendant announced there was a technical problem and that the Captain would brief us in 10 minutes. He never did and even though I was at the front (and the cockpit door was open) there seemed to be no technicians attending. After another hour, we finally closed doors and were rolled back. The Captain then announced that the delay was due to someone having left their mobile phone switched on!
I was sceptical, especially since there was no prior announcement asking the passengers to check if they had a phone switched on!
On arrival in Turkey I discovered from a colleague that Turkish actually had staged a wildcat stike in that afternoon and the Captain was "probably" involved.
So what would he have told us in the back if there was something really critical going on? Makes you wonder?

groundbum

ref mobile phones on-board - what an awful idea

but I wonder if the micro-cell on the plane could be configured so that only text/internet ip traffic could be sent, ie no voice traffic? That wouldn't be so annoying, and people could still be in touch via their mobile..

Still, would need to set the profile to "silent" as the incoming text message beepsx300 could be very very annoying

Simon

Leftit2L8

It's about the only time Mrs L and kidz aren't on the mobile. They even wanted to use the credit card phone in the seat of a 340 once presumably to talk about hair styles, boyfriends etc. etc. ! Please no !

Freeway

In view of recent events in Madrid and London where it was suspected that devices were detonated via mobile phone, I see it increasingly unlikely that phones will be allowed to be used on board in the future, thankfully.

Rwy in Sight

I am afraid that given the revenue involved for the airlines, network operators and aircraft manufacturers, we should consider the mobiles phones on board as a fait accompli.


Rwy in Sight

PAXboy

In principal - yes - but not straightforward. I expect that we shall see open use of phones. The only limiting factor being cost and the number of channels available for simultaneous calls.

The problem of people speaking too loudly on their mobile (cell) and thus disturbing neighbours will continue. The problem is not that they WANT to speak loudly but when you have loud noise around you, and so have difficulty hearing the person at the other end, you automatically compensate by speaking louder. In the open air, and on public transport the ambient noise levels are higher, so people spontaneously speak louder.

Not good but I expect that rules will be developed ... shortly after the first cases of Air Rage generated by excessive use of mobiles.

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"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.

Final 3 Greens

One can already use IP phones (e.g. Skype) on board Lufthansa, via the Boeing Connexions programme. I have used this facility to make important calls whilst on long haul flights and have not received any complaints, then of course I have made a reasonable amount and maintained a discrete volume.

I really don't see what is so sacred about aircraft, they are basically a noisy environment and phone calls are not shattering the peace, PAs, service, conversations and other factors already do that.

As with all things, such as reclining seats in Y, it is perfectly possibly to act in a reasonable way.

Thus the real issue is how to deal with unreasonable people, not mobile telephones.

christep

Freeway,

The bombs in Madrid were detonated by the alarm functions on the mobile phones. Whether or not you put pico cells on aircraft is going to make no difference to that. The London bombs were suicide bombers, and some were set off in areas with no mobile coverage. There is no evidence of any bombs having been set off by calling a mobile phone, and in any case, given the apparent ready supply of suicide bombers, it really doesn't matter how the bomb will be triggered - not having the explosives on the plane is the key.

Having said that I really, really don't want mobile phones in-flight.

Pax Vobiscum

I suspect that I know just enough about GSM technology to confuse myself, but here goes!

If a mobile tries to link to the on-board picocell and fails (because the picocell is out of capacity or otherwise disabled), won't it automatically boost its signal in an effort to contact the next nearest base station (30,000 feet below)? I understood that this can cause problems in the cellular network, both because of the speed at which the phone is travelling and also the number of base stations that can be simultaneously contacted from 6 miles up!

I'm hoping there's an expert lurking somewhere nearby, as I really don't want to read through all the GSM specs

PAXboy

PV, the person who will give the definitive is Radeng. My understanding is that the problem only exists when the a/c is on approach departure as the handset will fail to find another signal when it is at altitude.

However, the problem should not arise because, if the pico cell is busy, then the handset will still be registered to it. It will simply not be able to connect a call. When all voice channels are busy, the handset can still send and receive SMS (text msgs).

I sit to be corrected.

radeng

It's sometime since I did system design for GSM, but from memory...

Problem number 1 is Doppler shift. Depending upon the angle between aircraft track and ground station, the Doppler may be too much both for the base station and the handset to handle .

Problem number 2 is that the timing requirements in GSM give a maximum range to a GSM base of, from memory, 50km.

So if the on board picocell is loaded up, there's limited number of options for finding a base station. There's also suggestions in the discussions going on at producing a standard for this application about blocking all the other channels.

Seems to me to be an idea of people interested in encouraging anti social behaviour!

I can't help wondering (wandering off track a bit) if the London suicide bombers knew that they were suicide bombers, and weren't just carrying packages that they knew might be dodgy, but not realising what they really were. The close timing of the bombs suggests timers, but why would they be necessary? Suicide bombers with the bomb under their control could have gone to the Northern, Bakerloo and Victoria lines and set them off deep underground between stations, causing far more casualties. Plus the psychology of the individuals seems from reports to be wrong....

Pax Vobiscum

Thanks both - I knew I could count on you for a helpful explanation! It still seems to me that there could be a problem if the local picocell dies for whatever reason. I've heard stories of mobiles being left switched on during a flight receiving calls, but they may just be tall tales.

Regarding the London bombers, the same thought had occurred to me, radeng. I don't suppose we will ever know for sure.

PlasticCabDriver

PV, you are right, when the phone fails to make contact with a base unit it boosts its power each time it tries until it is at max power. Imagine now if all the phones on the aircraft are doing that, (beacuse they are at 30000' and can't find one) the harmonics of all those wiggly amps going up and down inside a slim metal tube have the potential to cause serious problems. Think what one phone sounds like when it "checks in" or rings near your stereo speakers or the car radio, and magnify that several hundred times and confine it to a small space.

There is a good story of an RAF VC10 going u/s twice in quick succession, because the nav was calling base ops on his mobile just before the take off roll (to tell them they were rolling!), and then finding that the fuel system circuit breakers had popped. After two goes the penny dropped.....

Mobiles on aircraft....Noooooooooooo!

PAXboy

Yes that is correct BUT if the phone has registered to the pico cell - then it will not ramp up it's output. As I said, if the cell is busy the phone will know that it is busy and will indicate 'network congestion' to you. This is what happens when any cellular network is congested, the phone simply cannot make a call and you keep trying until a channel is free. I sit to be corected.

I have no doubts that the lawyers will be wanting this problem well and truly sorted before they let it happen! And, NO, I do not look forward to that day.

Pax Vobiscum

Thanks again PAXboy - presumably in a terrestrial cell, the busy cell can direct registered phones to contact other local cells that it 'knows' to be less busy. But, what if a cell fails? I believe that the mobile has a 'keep alive' contact with the cell and if this isn't responded to the mobile will then try to contact another cell, which is when the problems could arise in flight.

Disclaimer: I'm happy to give anyone an argument about computer networks, but I really don't understand these tricky voice thingies! If this is getting too technical/boring, I'm happy to continue via PM (or just tell me to go away and read the ITU standards ... )

radeng

PaxVobiscum,

they are actually ETSI standards, not ITU. That's important if you really want to read them, because ETSI documents are free. And it was rapidly decided that in fact, GSM stands for 'Great Spec Mountain'. ITU Hq in Geneva: ETSI Hq is near Antibes - no choice which one is preferable!!!Without mentioning the young ladies cavorting nude on the beach at Antibes at midnight in the summer.....

Incidentally, ETSI, the European Telecommunications Standards Institute is a benefactor to the airline industry. This is because it has all these meetings spread around - it's sometimes called the European Tourism and Sightseeing Institute!

Pax Vobiscum

Thanks radeng - I used to know that once upon a time ...

Am I also barking up the wrong cell regarding problems caused by failure of the in-flight picocell

PAXboy

Not as far as I know. Essentially, each cell is 'dumb' and is controlled by a computer controlled switch. This does not (I think) have geographical knowledge. If the handset was only in range of one cell, then there is no possibility. But if it can contact other cells, it will re-register itself anyway.

Ahh, this is the technical bit ... it all goes very quiet. Any calls in progress will be dropped and any attempt to reconnect will be met with a report of 'No Network'. If you have roaming, you can then do so but this is usually only implemented for handsets visiting from another country. (long story)

Not too bad, I think. If the Pico Cell fails, local handsets will ramp up their signal strength but then (at FL 370) not find another cell and go quiet.

From an earlier thread (many moons ago) I recall someone (radeng?) explaining the sequence of when a handset will search but it is not as frequent as you may think. My guess is that, if the Pico Cell fails in flight, this would be noticed pretty sharpish by the pax and then, the CC or FC would notify the pax of the failure and ask that all handsets be turned off. Of course, this might be at night on a LH and they don't make announcements ... so the possibilities for fun are almost endless.

Oh, don't spoil the fun, it's just getting interesting! Remember that Voice is the one true faith.

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"I tell you, we are here on Earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut, Jr.

Someone Else

Good thread, pico cells will clearly become an issue before too long.

Handsets moving from the pico because it is busy, is not an issue.
Once the handset is registered with the cell (see below) it will stay on that network and only look at neighbouring frequencies give by the pico cell. The thing about the GSM system is that two types of channels are used. The first is a very low bandwidth signaling channel, while voice calls use a full traffic channel. Even a pico cell will have many of both. The signaling is only used for a few seconds at most, to register, send/receive a text message or to request a call set-up. It is extremely unlikely that a signaling channel wouldn’t be available so text messaging works even under high load conditions. At sometime during the setup of a voice call the network must allocate a traffic channel. If one isn’t available then the call setup will fail. This isn’t a reason for the handset to move networks, as it would be handled in the same as a busy or unobtainable number.

Registering with the pico cell
The issue that is more problematical is interaction of the pico and its network operator and ground based networks. In particular will the pico be operational while the aircraft is on the ground? I suspect not as it could take business away from ground based networks that have paid good money to get their operating licence.

Let’s assume the pico is permanently on for a moment, at boarding a mobile will be registered with a network, other than that of the pico, and will be monitoring its serving cell and those in its neighbour list. It will move from ground based cell to another ground based cell as long as it can using up to its full power as necessary. It is only when it can’t monitor or make contact with any of those cells that it will make a search of all networks and find the stronger signal from the pico cell.

For these reasons I guess that handsets will still have to be switch off during take-off and landing, as will the pico cell. That way the network search made when mobiles are switched on will find the pico as the strongest cell.