there were telecom rules that banned you from using mobiles from aircraft because you can log into too many towers
Faster causes tower problems
I've been looking into this on & off for years and asking anyone I have come across with appropriate knowledge or skills in the mobile network area...
Seems to be a common refrain as I hear this around the bar at the flying club from time to time and on here more than once in the last many years.
I've never been able to get a definitive answer and would appreciate it if someone is able to point to something tangible.
The best I've been able to find was an article that referenced another (American) article on the subject saying that either the FAA/FCC had come to such a conclusion. However, how the conclusion was reached was not disclosed and the actual mobile network "tested" was not defined. Its been quite a few years and I no longer seem to have the bookmark but I believe that the article was written in the late '90s. At that time America was pre-GSM so the mobile networks were based on AMPS & D-AMPS. So I have always assumed that any "test" that may have led to the conclusion that "using a mobile while flying causes problems with the mobile network because the mobile camps on many cells because it can see many cells at the same time and therefore clogs up the network" was based on these older mobile network systems.
GSM systems were designed for the fast inter-city trains found in Europe at the time the GSM system was defined. Most small GA aircraft fly at or slower than these fast trains. The GSM system is designed to measure the speed of the mobile and decide which coverage layer to push the mobile to (macro, micro, pico) to reduce the handover rate and therefore, the amount of signalling within the core network. GSM systems have cells of different frequencies and reuse frequencies geographically for capacity reasons. However, even if your high enough to see many of these cells at the same time - you'd have to be higher than typical GA (over 10,000ft at greater than 5W) to have any affect. Mobile phones are typically 500mW only. As macro cells are typically 35miles wide - at 2000ft @5W the radio horizon is approx. 40miles and you'd see maybe three cells. At 5000ft @5W the radio horizon in approx. 70miles and you'd see maybe seven or so cells. At 10,000ft @ 5W the radio horizon is approx. 110miles so you'd see maybe a dozen or so cell sites. The typical macro frequency reuse distance is 9 cells. So at 10,000ft you would typically only see maybe two cells of the same frequency. At 500mW the distances will be less than the examples above...
Now UMTS and LTE systems are totally different. The UMTS system was designed for the newer high speed trains found in Europe and can cope with higher speeds. Also UMTS & LTE systems are actually designed so that a mobile can transmit and receive from multiple cell sites at the same time in normal operation. In many cases; these cells all work on the same frequency so in the example above it would be normal operation to have multiple cells talking to your mobile and your mobile talking to multiple cells all at the same time. The download speed increases in LTE and LTE-A are from techniques where data is sent to the mobile from multiple cells at the same time. The same is true for upload speed increases. So in the situation above even if your mobile signal was received by multiple cells - the system would either make use of it or ignore you. If the cell ignores your mobile then you are seen as just noise to be filtered which is normal operation.
I have to put the caveat that I'm knowledgeable of many areas of mobile networks but would not consider myself an expert. I'm also not a frequency planner (but sit next to one on a day to day basis). So I'm happy to be corrected on any of the above.
So from my thinking and understanding - and I'm happy to be corrected with tangible evidence. The issue of "using a mobile while flying causes problems with the mobile network because the mobile camps on many cells because it can see many cells at the same time and therefore clogs up the network" nobody looses any sleep over as by the nature of the current mobile network systems it is not a problem and the systems deal with it as designed.
However, you will burn through your mobile's battery much faster as if it is GSM it will transmit at maximum power until it gets a response. If UMTS/LTE it will try an educated guess at an appropriate transmit power - if no answer from the network it will increase the power and keep going through this cycle until it is transmitting at maximum power where it will remain. If the mobile has a signal and camped on the network; when flying there is a greater chance of the mobile moving between location areas and routing areas faster than when walking, driving or on fast trains so the mobile will be very chatty. (this is what you hear when a GSM mobile interferes with audio frequency amplifiers - the chirp chirp you hear in your headphones)
However, the legal side of using non-approved telegraphy equipment in an airplane is another matter entirely...