I'm calculating the max doppler frequency of a fading channel in an in-room environment and looking at different carrier frequencies. Calculated as follows:
F = vf/c
Where
F -> max doppler shift
v -> Velocity of object
f -> carrier freq
c -> speed of waves in medium
At lower frequencies (ultrasound), I use the speed of sound. At higher frequencies (GSM range), I use the speed of light. How do I know when the acoustic medium ends and the light medium begins?