Base station polarization diversity reception in macrocellular systems at 1800 MHz

Measurements of the signal envelopes in two-branch base station polarization and space diversity reception have been performed in macrocellular urban and suburban non-line-of-sight environments at 1800 MHz. The ratio of the median power in the horizontally polarized signal to the median power in the vertically polarized signal was in the range -1 to -7 dB for a hand-held mobile and -7 to -13 dB for a vertical antenna mounted on the roof of a measurement van. The cross-correlation between polarization diversity branches was less than 0.2 for most of the measurement routes. Using the average signal levels and the cross-correlation coefficients the diversity gain in a noise-limited GSM system was estimated. The gain is normally smaller with polarization diversity than with space diversity, but for many of the environments the difference is only about 1 dB in a GSM system. A statistical model for the horizontal-to-vertical power ratio is also presented