Unitary Precoding for MIMO Interference Networks
For MIMO interference networks, uncertainty in the spatial structure of interfering signals is a major source of performance degradation. In this paper, the authors promote the use of linear unitary precoding, as it can be designed such that downlink transmission becomes more robust. Optimizing linear unitary precoding is a combinatorial and non-convex problem, thus no efficient methods to compute global optimal solutions are available. Therefore, methods with reasonable complexity and acceptable performance are desired and have been investigated in research literature as well as for practical implementation. Contrary to existing work on unitary precoding, which considers receivers with a single antenna, they target scenarios with multiple receive antennas.