A space diversity channel model for multipath propagation measurements in New Zealand

The authors describe the results of a 140 Mb/s 64 QAM (quadrature amplitude modulation) digital microwave radio field trial to characterize a space diversity channel model with maximum power (MAP) combining. Measurements were taken on a 60.8-km overwater route in New Zealand. To the spectral data collected from the field trial, a Rummler-type model has been fitted. The PDFs of the nondiversity and diversity channel model parameters are estimated from the measured data. The simulation of a MAP combiner on the nondiversity Rummler fits was found to be useful in obtaining statistics of the model parameters for a combined channel. It was found that the same general class of distributions could be used for the combined channel as was used for the nondiversity channel parameters. The combiner was effective in reducing in-band notch depths. The distributions of notch position and flat-fade component were not greatly altered by the combiner. Two diversity antenna spacings were compared, and the smaller spacing performed marginally better.<>