Mobile phones on aircraft

Mobile phones on aircraft

The U.S. Federal Communications Commission prohibits the use of mobile telephones aboard any aircraft in flight. The reason given is that mobile phone systems depend on channel reuse, and operating a phone at altitude may violate the fundamental assumptions that allow channel reuse to work.
Mobile telephones are intentionally designed with low power output. A tower is the center of a "cell" and due to attenuation with distance (inverse square law) a phone can usually be received only weakly by towers in adjacent cells, and not at all in cells farther away (non-adjacent cells). This allows the channel used by any given phone to be reused by other phones in non-adjacent cells. This principle allows tens or hundreds of thousands of people to use their phones at the same time in a given metropolitan area while using only a limited number of channels.