摘要
In this letter, we study the degrees of freedom (DOF) for multiple-input-multiple-output (MIMO) Y channel in frequency division duplex (FDD) systems. Assuming each node has delayed channel state information at the transmitter (CSIT), we propose a physical layer network coding multi-stage transmission (PLNC-MST) scheme during broadcast (BC) phase. The results show that PLNC offers significant DOF gain in MIMO Y channel.