Antenna Array Calibration In The Wcdma Mobile Communication System Technology Research

WCDMA is a promising radio access technology for third-generation mobile communication systems because of its high flexibility to support a variety of voice and data service. The smart antenna array calibration is one of the key techniques which are able to improve system performance. Based on plenty of existing research findings at home and abroad, this thesis studies several online calibration algorithms with an auxiliary signal source for the WCDMA-based adaptive antenna array according to their practical application.In the thesis, we introduce the generation and characteristic of the unknown amplitude and phase errors of the responses of the antenna array, and the WCDMA signal model for an antenna array is described on the basis of 3rd Generation Partnership Project (3GPP). We give two calibration projects with an auxiliary signal source for calibration. The auxiliary signal is injected into antennas from the ports of antennas in the first calibration project for channels uncertainty. This thesis studies the Least Squares (LS) algorithm, the subspace-based algorithm and the correlation algorithm based on the mentioned project. The auxiliary signal is near by the base-station in the second calibration project for mutual coupling existing between sensors and channels and sensors uncertainty. In this project, this thesis also studies the LS algorithm, the subspace-based algorithm and several approaches based on adaptive filter theory, such as the Least Mean Squares (LMS) algorithm, the constant modulus (CM) algorithm and the Recursive Least mean Squares (RLS) algorithm. The two calibration projects are both based on de-spreading the reference signal. Because they require a prior knowledge of the auxiliary signal, such as PN spread code, DOA, constant modulus and so on, the fast and robust convergence can be ensured, and the Multiple-access interference (MAI) can be eliminated. The above algorithms can all be applicable to a non-uniform array where the number of users can be greater than the number of antennas. Computer simulation and practicalresults demonstrate that these algorithms are effective.