Regularized Channel Distribution Inversion (RCDI) and Parameterization in the MIMO Broadcast Channel

Linear precoding (beamforming) techniques exist that maximize the sum rate in multi-antenna broadcast channels. Such algorithms require accurate channel state information (CSI) at the transmitter and are performance sensitive to erroneous or outdated CSI. The current work focuses on adapting these algorithms to work on the statistics of the channel, rather than channel state, in order to provide more stable performance. This stable beamforming method is shown to require the full spatial correlation matrix thus suffering from high complexity in the feedback channel. Parameterization of the spatial correlation using popular channel models is also considered to make the proposed beamforming practical.