Europe approves use of in-flight electronics during take-off and landing

Re:Europe approves use of in-flight electronics during take-... by mikeash on Thursday November 14, 2013 @07:15PM (#6736782)

My understanding is that the problem isn't with the speed of the handovers, but rather with the fact that the horizon is a major block to radio signals, and the horizon is much farther away when you're at altitude.

Older networks were designed around the fairly reasonable assumption that a cell phone would only ever be able to talk to adjacent cells, because anything farther away would be over the horizon. So you might be able to talk to both A and B at the same time, but you couldn't talk to C without first losing contact with A.

Raise the phone a few thousand feet in the air and this assumption goes out the window, confusing the network. There's an amusing story of a pilot who called up his family to let them know he was almost home and ended up getting billed for the call (at expensive 80s rates) a bunch of times because several different towers all thought they were running the call.

There's certainly no problem today, anyway.

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Re:Europe approves use of in-flight electronics during take-... by Zigurd on Thursday November 14, 2013 @07:29PM (#6736883)

> Older networks were designed around the fairly reasonable assumption that a cell phone would only ever be able to talk to adjacent cells, because anything farther away would be over the horizon

That can't possibly be true. Spectrum re-use in distant sites could in theory have some effect on the call but differences in signal strength would make significant effects unlikely.

Also, that story about the pilot must also be apocryphal. A handover is a handover, and there is only one "winning" decision. Not to mention that CDRs don't work that way.

Lots of civil aviation pilots use mobile devices in the air without problems for the user or network.

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Re:Europe approves use of in-flight electronics during take-... by mikeash on Thursday November 14, 2013 @07:50PM (#6736972)

You may be right about the story, but I don't really see the obstacle to it happening. If you initiate a call in the air, you could easily not be able to communicate with the cell directly below (since they don't radiate much signal upwards) while being able to talk to two that are adjacent to it. Since those two cells would never have a reason to communicate in normal operations, confusion ensues.

I know that lots of pilots use mobile devices now, but we're talking ~30 years ago.

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