Two distinct mechanisms
Time dispersion
-
Time variations of the channel are caused by motion of the antenna
-
Channel changes every half a wavelength
-
Moving antenna gives Doppler spread
-
Requires short symbol times
-
Interleaving may help
Frequency dispersion
-
Delay profile causes intersymbol interference
-
Frequency selective fading
-
Requires long symbol times
www.WirelessCommunication.NL Slide Show