On the Capacity Region and the Generalized Degrees of Freedom Region for   the MIMO Interference Channel with Feedback
  In this paper, we study the effect of feedback on two-user MIMO interference channels. The capacity region of MIMO interference channels with feedback is characterized within a constant number of bits, where this constant is independent of the channel matrices. Further, it is shown that the capacity region of a MIMO interference channel with feedback and its reciprocal interference channel are within a constant number of bits. Finally, the generalized degrees of freedom region for the MIMO interference channel with feedback is characterized. 
Mehdi Ashraphijuo and Vaneet Aggarwal and Xiaodong Wang
cs.IT math.IT