On the capacity of vector Gaussian interference channels

The capacity of a vector Gaussian interference channel is investigated. Outer bounds, and where possible, capacity regions of a class of interference channels is characterized. The analysis of single transmit multiple receive antenna (SIMO) Gaussian interference channels with strong interference can be easily seen to be exactly analogous to that of a single transmit single receive antenna system. This paper demonstrates that, in contrast, multiple transmit single receive antenna (MISO) Gaussian interference channels are much harder to characterize. In this paper, the capacity region for a class of MISO interference channels with very strong interference is characterized. Also, the rank of the optimal transmit policy in a MISO Gaussian interference channel is shown to be bounded by the number of users in the system. Finally, outer bounds on the capacity region of the general multiple transmit and receive antenna (MIMO) Gaussian interference channels are derived. A new outer bound is obtained, which combines and improves previously known strategies for bounding the capacity of interference channels.