CTIA Wants More Testing of In-Flight Calling
Top message: Thats bogus man! by Natas
Replying to: Re: in this case by Natas
All cell phone network technology was designed with the assumption that the phone will be on the ground. This includes several other assumptions, such as you will never be in range of more than a handful of towers (because terrain will block the far-away ones,) when you move (hand off) from one tower to another, they will be near each other, and you will never move faster than 120 MPH (on an Amtrak Metroliner, for example).
Another thing you need to know is that phones automatically, constantly adjust their output power. They always transmit at the minimum power level necessary to reliably reach the nearest tower.
So, if you're in a plane and try to use your phone today, it will broadcast at maximum power to reach the ground. This may work in some cases, but because it breaks all of the assumptions listed above, it will wreak complete havoc on the cell phone network.
You'll be moving too fast, you may be in range of too many towers at once (because they are all line-of-sight - nothing in the way but air,) and you may hand off from one tower to another that is hundreds of miles away. This is not good for networks. Not at all.
If everyone tried to use their phones like this today, the networks would probably just grind to a halt. That's why the FCC (not FAA) currently bans phones in flight.
Now, the reason they are considering changing that is to allow new picocell-based systems, which effectively put a tower on the plane. Because phones only transmit just enough to reach the nearest tower, this should eliminate problems with the ground.
At least that's the theory. It's been demonstrated, but not tested extensively, which is why the CTIA is concerned. Because if it doesn't work at least 99% of the time, it could be a major problem for the ground networks.
Another problem I could see is confusion over different network technologies. For example, if the plane is equipped with CDMA and GSM picocells, and someone fires up a TDMA or iDEN phone, it could be big trouble. Plenty of people don't know what technology their phone uses, so I don't know how the airlines plan on educating their passengers about which types of phones can or can't be used on board...
- Re: more info by pwfb