Delayed Crosstalk Digital Predistorter for MIMO Systems

In modern wireless communication systems, multiinput multi-output (MIMO) technology has been pivotal in achieving high data rates and enhanced spectral efficiency. However, the nonlinear behavior of Power Amplifiers (PAs) in MIMO systems can significantly degrade system performance. This paper proposes a novel delayed crosstalk digital predistorter (DC-DPD) model for (MIMO) radio systems. The proposed model demonstrates that incorporating delayed crosstalk improves the performance of the digital predistorter. The model was subjected to experimental validation utilizing an Orthogonal Frequency Division Multiplexing (OFDM) signal with a bandwidth of 50 MHz and employing 64-QAM modulation using the same model with and without the delayed crosstalk. Experimental results show that the DC-DPD model outperforms by up to 3 dB the 2D memory cubic spline basis (MCSB) model DPD of Normalized Mean Square Error (NMSE) and Adjacent Channel Power Ratio (ACPR).