Space-time coding and beamforming with partial channel state information

in this paper, a STBC/BF hybrid technique is proposed for outdoor multipath multi-input multi-output (MIMO) channel. Depending on the amount of partial channel state information (CSI), this system evolves from pure diversity waveform signalling to pure beamforming. The performance of this technique, in terms of signal vs noise ratio (SNR), is investigated in various multi-input single-output (MISO) scenarios. Though the method is evaluated in MISO, we give a simple way to extend it to MIMO case. In addition, a beamforming scheme based on sub-space approximation is also discussed which can reduce the amount of feedback from the receiver to transmitter. Simulation results are given at the end of this paper.