Antenna phase estimation algorithm for wcdma closed loop transmitter antenna diversity system

Abstract

This invention teaches a method for use in a wideband CDMA telecommunications system wherein the base station (BS) utilizes transmit antenna diversity. The method enables the user equipment (UE) to perform a channel estimate for channels received from two antennas of the base station (BS), and includes steps of: (a) computing an estimated phase difference between a common pilot channel and a dedicated pilot channel received from one antenna of the two antennas; and (b) determining the channel estimate by rotating a common pilot channel estimate according to the estimated phase difference, where the phase difference is computed as a complex coefficient between the common pilot channel and the dedicated pilot channel. In a second aspect this invention teaches a method for use in a transmit antenna diversity system for enabling the UE to verify an antenna phase shift previously signaled by the UE to the BS. This method includes a first step of: (a) exploiting prior knowledge of BS rotation angle by considering a vector x that includes all hypotheses for complex rotation coefficients of the BS with respect to all possible rotation angles, in accordance with a decision rule for an estimation of a complex rotation coefficient. A second step of the method evaluates a cost function of a hypothesis m by considering the prior knowledge.