On the degrees of freedom of rank deficient interference channels

Abstract

We analyze the achievable degrees of freedom (DoF) of the time-varying K-user rank deficient (M, N, D) interference channel (IC) in which each transmitter and receiver uses M and N antennas, respectively, and the rank of each channel matrix is equal to D ≤ min (M, N). The proposed achievable schemes are based on zero forcing and interference alignment. We see that the total DoF of min (DK, max(M+N-D,(DL/L+1)K)) is achievable, where L=(max(M,N/D)) and (x) denotes the integer part of x. The result shows that the achievable total DoF of the K-user (M, N, D) IC has similar tendency to that of the full rank IC.