  For a $K$-user interference channel with $M$ antenna at each transmitter and
each receiver, the maximum total DoF of this channel has been previously
determined to be $\max \sum_{k=1}^K d_k = MK/2$. However, the DoF region
remains to be unknown. In this short note, through a simple time-sharing
argument, we obtain the degrees of freedom (DoF) region of this channel.
