Decision Feedback Equalization of Dispersive Radio Channels

The performance of adaptive decision feedback equalization applied to high bit rate digital radio systems in the presence of multipath propagation is analytically investigated. Minimum phase (MP) and nonminimum phase (NMP) type fades as well as the transition periods between these two states are considered. Insight is given into the IF recovered timing epoch and its consequences on the decision feedback equalizer (DFE) behavior, especially during transition periods. Required conditions on the DFE structure for ensuring its maximum efficiency are derived and a modified updating algorithm is presented. Finally, dynamic simulation results are reported and compared to theoretical results. They show that the proposed structure is capable of coping with most propagation conditions.