US Patent 11936343 Per-branch, combined, and grouped combined MIMO DPD

Systems and methods are disclosed herein for Digital Predistortion (DPD) in a Multiple Input Multiple Output (MIMO) transmitter. In some embodiments, a MIMO transmitter comprises a plurality of antenna branches comprising a respective plurality of power amplifiers coupled to a respective plurality of antenna elements. The MIMO transmitter also includes one or more DPD systems operable to predistort one or more respective groups of input signals to provide one or more respective groups of predistorted input signals for one or more respective groups of antenna branches. Each group of antenna branches comprises at least two of the plurality of antenna branches. In some embodiments, the MIMO transmitter is a massive MIMO transmitter. Embodiments of a per-branch DPD scheme for a MIMO transmitter that uses Iterative Learning Control (ILC) and kernel regression are also disclosed.