New adaptive downlink beamforming method for WCDMA system

One of the main issues for downlink beamforming with a smart antenna system is the impact of the desired user on other subscribers. Downlink beamforming for the desired user will change the interference to all other subscribers. We propose a new algorithm employing the conjugate gradient method (CGM) to mitigate the effect of interference. This algorithm is termed adaptive interference mitigation using CGM (AIM-CGM). We compare the performance of this algorithm with a conventional beamformer using the signal format of frequency division duplexing (FDD) wideband code division multiple access (W-CDMA).