Outer bounds for the MIMO interference channel

We derive several new outer bounds on the capacity of the MIMO Gaussian interference channel. Many of the bounds presented herein are extensions of the work by Etkin et al. (2007) on the single antenna interference channel. These bounds are compared with a Han and Kobayashi achievable rate region and we show the conditions when the achievable rate approaches the outer bound. We also describe the conditions when the outer bounds are concave, thus guaranteeing a computable outer bound.