On the degrees of freedom of X channel with delayed CSIT

We consider the X channel and the 3-user X network with independent and identically distributed fading across antennas and channel uses and with the delayed channel state information at the transmitters (CSIT). We provide new results for degrees of freedom of these channels. Specifically, we show that the single antenna X channel with delayed CSIT can achieve 6/5 degrees of freedom while the 3-user X network can achieve 5/4 degrees of freedom.