Types of Distortion:

  • Additive White Guassian Noise (AWGN) : Formula - Electrical White Noise
  • Fading : Formula- The forces of nature, be it rain snow or clouds affect the way EM waves propogate
    • Slow Fading - slow changes to the system that happen much longer than the message you want to send, considered as a static loss
    • Fast Fading - this is fading that varies during the transmission of a single message, and is the main problem for transmission. The minimum time required for a message to be uncorrelated to it’s previous value is , which is related to Doppler Spread
  • Rayleigh Fading - The doppler effect from moving objects physically spreads apart our Fourier Transform of the signal as is described as :