1. An apparatus comprising: at least one processor configured to determine performance metrics for a plurality of ranks, each rank indicative of a different number of data streams to send simultaneously via a multiple-input multiple-output (MIMO) channel, to apply adjustments to the performance metrics for the plurality of ranks to obtain adjusted performance metrics, the adjustments accounting for system losses, and to select a rank to use for data transmission from among the plurality of ranks based on the adjusted performance metrics; and a memory coupled to the at least one processor.