Analysis of diversity performance of space diversity and cross polarization for PCS base stations

Abstract

The objective of the polarization diversity measurement program is to compare and evaluate the efficacy of a single unit polarization diversity antenna relative to the classic vertically polarized two antenna horizontal space diversity configuration. The two base station antenna configurations were tested simultaneously for both vertical polarized mobile antennas and randomly oriented portable antennas. The methodology and data reduction techniques used in the analysis were similar to those used in work by Turkmani et al. (1995) in Europe and by Weitzen et al. (1996). It was observed that bottom line PCS performance with a randomly oriented portable unit was almost identical for polarization and space diversity systems. For a vertical mobile antenna the bottom line performance was approximately 3 dB worse for the polarization diversity system relative to the horizontal space diversity system with vertical polarization. Significant polarization discrimination, that is one slant favored over the other was observed at close ranges (less than 1 km) when there is a nearly clear line of sight between mobile and base. Significant depolarization was observed at longer ranges and when the mobile is in the clutter.