Degrees of freedom region of MIMO interference channel with imperfect current and delayed CSIT

Yi Luo, Anastasios K. Papazafeiropoulos, Tharm Ratnarajah

Abstract: In this paper, we study the degrees of freedom (DoF) of the two-user time-correlated multiple-input-multiple-output (MIMO) interference channel (IC), under realistic assumptions. In particular, the transmitters have imperfect knowledge of the current and the delayed channel state information (CSI). The novelty of this study relies upon the fact that this is the first time, within the literature of IC, that imperfect CSI is addressed for such a case. The delayed CSI at the transmitter (CSIT) is assumed to be more accurate than the current value. We identify the DoF region, which provides an insight on the behaviour of the DoF as a function of the varying qualities of the current and the delayed channel. It is also worth mentioning that any knowledge of imperfect delayed CSIT can also be utilized. Furthermore, an achievability scheme is proposed for each vertex in DoF region. Finally, simulation of the proposed scheme verifies our results.