On fading broadcast channels with partial channel state information at the transmitter

Abstract

The two user multiple-input multiple-output (MIMO) broadcast channel is studied in which the channel from one of the receivers is known instantaneously and perfectly at the transmitter, whereas the channel from the other receiver is known in a delayed manner. The degrees of freedom (DoF) region of the two-user (M; N1; N2) - MIMO broadcast channel under this model is completely characterized. The scheme illustrates the joint utilization of current and past knowledge of the channel state information at the transmitter.