A Measurement Based Approach to Spatially Predict the Orthogonality Factor of the UMTS Downlink

Commercial HSDPA measurements are used in order to derive an approach for the location based orthogonality factor. It is found that the orthogonality factor is correlated with the difference between the free space path loss and the measured path loss. A path loss difference close to 0 dB indicates line of sight and the maximal orthogonality factor is reached. With increasing path loss difference the orthogonally factor decreases rapidly. The approach includes the distance as well as the land usage dependency of the radio path and it requires only input data which is generally available in macro cell propagation models. The HSDPA data rates predicted with a macro cell model in a commercial planning tool agree well with measurements.