a method for improving multiple - input multiple - output mimo downlink transmissions includes obtaining a channel state information csi report including preferred matrix index pmi for precoding , channel quality index cqi and rank index ri at a base station from user terminals through a channel feedback ; applying selectively a signal - to - interference - plus - noise - ratio sinr offset to a sinr of said csi report ; applying selectively a rate matching responsive to sinr offset or the csi report ; and controlling or adjusting the sinr offset .