Maximum-power and amplitude-equalizing algorithms for phase control in space diversity combining

Two phase control algorithms for space diversity combining are analyzed, comparing the performance capabilities of a maximum-power and an amplitude-equalizing algorithm. The conventional maximum-power combiner is reviewed, describing in detail a particular implementation of the maximum-power phase-control algorithm. It is shown how the maximum-power algorithm can be converted into an equalizing algorithm by judiciously extracting a phase-control signal from selected portions of the combined-signal spectrum. The analysis reveals that the maximum-power algorithm is only a special case of a more general algorithm that can adaptively maximize the combined signal power over any frequency interval in the channel. The results of computer simulations illustrating the response of the maximum-power and equalizing combiners to dispersive channel conditions are presented. An improvement factor of the equalizing combiner over the maximum-power combiner is calculated for several assumed probability-density functions of the parameters of a two-ray fading model.