On Multiuser MIMO Multistream Transmission

We present a system for multiuser multiple-input–multiple-output (MIMO) multistream downlink transmission, which employs covariance-based linear precoders at the transmitter and a minimum-mean-square-error (MMSE) equalizer at each receiver. Antennas of user equipment are arranged to receive different streams bound to this user. Furthermore, these antennas receiving different streams are allowed to cooperate with each other through a joint equalizer, leading to a multiuser MIMO multistream transmission link. The precoders are designed per stream based on the covariance channel state information (CSI). Numerical analysis shows the feasibility and usefulness of the presented system. With the proposed approach, the covariance-based precoding concept for multiuser multiple-input–single-output (MISO) single-stream transmission can effectively be extended to a multiuser MIMO multistream transmission link.