http://en.wikipedia.org/wiki/Orthogo...n_multiplexing

From wikipedia:

Summary of advantages
*High spectral efficiency as compared to other double sideband modulation schemes, spread spectrum, etc.
*Can easily adapt to severe channel conditions without complex time-domain equalization.
*Robust against narrow-band co-channel interference.
*Robust against intersymbol interference (ISI) and fading caused by multipath propagation.
*Efficient implementation using Fast Fourier Transform (FFT).
*Low sensitivity to time synchronization errors.
*Tuned sub-channel receiver filters are not required (unlike conventional FDM).
*Facilitates single frequency networks (SFNs); i.e., transmitter macrodiversity.


On Saturday, April 13, 2013 1:13:33 PM UTC-7, Bear wrote:
What is your proposal?





So, how is digital communication with 17,000 mph satellites possible with Doppler effects?



Nobody suggested GSM as an alternative to a global aviation-specific digital communications protocol.