Degrees-of-Freedom Region of Time Correlated MISO Broadcast Channel with Perfect Delayed CSIT and Asymmetric Partial Current CSIT

Abstract: The impact of imperfect CSIT on the degrees of freedom (DoF) of a time correlated MISO Broadcast Channel has drawn a lot of attention recently. Maddah-Ali and Tse have shown that the completely stale CSIT still benefit the DoF. In very recent works, Yang et al. have extended the results by integrating the partial current CSIT for a two-user MISO broadcast channel. However, those researches so far focused on a symmetric case. In this contribution, we investigate a more general case where the transmitter has knowledge of current CSI of both users with unequal qualities. The essential ingredient in our work lies in the way to multicast the overheard interference to boost the DoF. The optimal DoF region is simply proved and its achievability is shown using a novel transmission scheme assuming an infinite number of channel uses.