The downlink orthogonality factors influence on WCDMA system performance

The large scale statistics of the downlink orthogonality factor (OF) is addressed in this paper for typical urban macrocellular environments for terminals with standard Rake receivers. It is found that the OF improves as the user moves closer to the BS and the OF is positively correlated with the shadow fading component of the radio channel. The mean value of the OF is typically larger for users dominated by own cell interference over other cell interference. These effects result in a larger excess capacity close to the BS, compared to scenarios where the OF is assumed to be constant within the cell.