Beamforming and aligned interference neutralization achieve the degrees of freedom region of the 2×2×2 MIMO interference network
Chinmay S. Vaze, Mahesh K. Varanasi · 2012
We study the layered two-hop, two-unicast multi-input, multi-output (MIMO) interference network, which consists of two transmitters, two relays, and two receivers with the first and the second hop networks between transmitters and relays, and between relays and receivers, respectively, both being Gaussian MIMO interference channels. The DoF region is established in the general case, where there are arbitrary numbers of antennas at all terminals. It is shown that the DoF region coincides with the min-cut outer-bound, and is achievable via a scheme involving beamforming and aligned interference neutralization.