Apparatus and method for uplink closed loop transmit diversity

摘要

An apparatus, method, and computer program product operable to determine a phase of a beamforming weight vector utilizing a memory of a previously used phase for the beamforming weight vector, capable of improving a channel estimate. A base station transmits a beamforming weight vector to a user equipment based on a determined channel estimate. The user equipment selects between the received beamforming weight vector, or a modified beamforming weight vector having its phase shifted by −360°, in accordance with a suitable selection criteria. That is, the selection is made such that a difference between the phase of the selected beamforming vector and a phase of a prior beamforming vector is within a predetermined range.

主权项

1. A method of wireless communication operable at a user equipment, comprising:
transmitting a first uplink transmit diversity signal by applying a first beamforming weight vector; receiving a beamforming weight vector in response to the first uplink transmit diversity signal; determining a modified beamforming weight vector based on the received beamforming weight vector; selecting one of the received beamforming weight vector or the modified beamforming weight vector in accordance with a selection criteria, the selection criteria being based on a difference between a phase of the selected beamforming weight vector and a phase of the first beamforming weight vector; and transmitting a second uplink transmit diversity signal by applying the selected beamforming weight vector.