Quantifying code orthogonality factor for UTRA-FDD down-links

The degradation of code orthogonality due to multi-path propagation has a direct impact on DS-CDMA system performance. A novel approach in deriving the orthogonality factor, which quantifies this degradation, is presented. Code orthogonality factors for realistic radio channels are calculated and the results analysed. The extension of the derivation to cover down-link beamforming investigates its effectiveness in preserving code orthogonality.