Exploiting both statistical and stale CSIT for linear precoding in MISO broadcast channel

In this paper, a downlink transmission scheme exploiting both statistical and stale channel state information at the transmitter (CSIT) is proposed for the multiuser multiple input single output (MISO) broadcast channels. On the basis of the original stale CSI-aided scheme introduced in [1] (denoted as MAT) and its derivative schemes (respectively denoted as GMAT and V-MAT in [2] and [3]), an approximation of the sum average mutual information is maximized to determine the precoding vectors during the consecutive three slots of the two-user scenario. In this paper, the two-user transmission protocol is the basic component for the extending multiuser scenario. Moreover, an efficient algorithm is derived to separately solve the optimization problem of different users in different slot for arbitrary number of transmit antennas. Numerical results show that the proposed scheme yields higher achievable rate than the existing relevant precoding strategies.