Patent attributes
Methods and apparatus for increasing diversity gain at a receiver by applying beamforming to transmit diversity space-time coded signals. A transmit signal is space-time coded over a plurality of space-time antenna groups, with each space-time antenna group associated with a specific space-time code. The signal at each space-time antenna group is beamformed over the plurality of antenna in the space-time antenna group. Each of the plurality of antenna in a space-time antenna group is weighted with a distinct weight, relative to the other antenna in the space-time group. The beamforming weights can vary based on a channel quality feedback indication from a receiver. The amplitude, phase, or a combination of amplitude and phase of each weight or of a vector of multiple weights can vary as a function of the channel quality indication in order to improve the quality of the received signal.
