Matrix-based orthogonal polynomials for MIMO transmitter linearization

Orthogonal polynomials have been considered as a powerful tool for power amplifier behavioral modeling and Digital Predistortion (DPD) linearization. The application of orthogonal polynomials was limited to SISO systems. This paper extends the idea to MIMO applications and demonstrates the linearization of 2×2 MIMO transmitters in the presence of RF crosstalk using matrix-based orthogonal polynomial linearization architecture. The performance of the proposed DPD has been evaluated using WCDMA and WiMAX standards. By incorporating the proposed DPD linearization topology, the measured ACPR of the WCDMA signal was improved from -42 dBc to -59 dBc and the measured EVM of WiMAX signal was reduced from -25 dB to -52 dB.