Global calibration of CDMA-based arrays

In this paper, a calibration approach capable of handling simultaneously location, gain and phase uncertainties, as well as mutual coupling (global calibration), is proposed for asynchronous CDMA-based antenna arrays in the presence of multipath. The manifold vector is modelled based on a first order Taylor series expansion, to encompass the errors. The calibration technique involves a hybrid combination of pilot calibration and self calibration techniques, and requires the code sequence of a reference user. This method employs the concept of the STAR (Spatio-Temporal ARray) manifold vector and a subspace type preprocessor to provide estimates of the path delays and directions, as well as estimating the array manifold, location, gain and phase errors taking mutual coupling effects into consideration.