Enhanced Equalization for Mobile Communication Systems

In this paper a prefiltering method is considered where an all pass filter is employed at the receiver before equalization to create a minimum phase overall impulse response. In the presence of ISI, the all pass filter concentrates the maximum symbol energy in the correct sampling instances and subsequently cancel the non causal precursor ISI by replacing the samples and channel by their minimum phase equivalent. The system performance attainable with the proposed equalization is determined for transmission with channel coding. The use of all pass filtering is beneficial to the performance of a communication receiver that operates in a dispersive multipath propagation environment and thereby improves capacity. Simulation results are given, which demonstrate that the proposed approach outperform the conventional decision feedback equalizer.