Performance Comparisons Among Digital Radio Techniques Subjected to Multipath Fading

This paper compares the performance of different digital radio techniques in the presence of multipath fading. The measure used is the expected fraction of time, conditioned on the occurrence of a fading event, that the eye pattern at the receiver detector is closed. This measure is plotted against spectral efficiency for various types of modulation and for various forms of carrier recovery, timing recovery, transmit/receiver filtering, and adaptive equalization. The computations assume a multipath fading frequency response described by a first-order complex polynomial, where the coefficients obey an empirically derived probability law reported previously.