On the Capacity of MIMO Interference Channels
  The capacity region of a multiple-input-multiple-output interference channel (MIMO IC) where the channel matrices are square and invertible is studied. The capacity region for strong interference is established where the definition of strong interference parallels that of scalar channels. Moreover, the sum-rate capacity for Z interference, noisy interference, and mixed interference is established. These results generalize known results for the scalar Gaussian IC. 
Xiaohu Shang, Biao Chen, Gerhard Kramer, H. Vincent Poor