Orthogonalizing Transmission in MIMO with Linear Receiver and Finite MCS Set

Using channel dependent precoding, a MIMO channel can be orthogonalized, which provides throughput gains especially if a linear receiver is used. When there is a limited set of modulation and coding schemes (MCS), however, we show that orthogonalization is not always the throughput maximizing strategy. Close to the upper and lower ends of operation points of the MCS set, it may be optimal to anti-orthogonalize the channel instead.