2D forward twin nonlinear two-box model for concurrent dual-band digital predistortion

In this paper, a dual-band forward twin nonlinear two-box model is proposed to compensate for the nonlinearity of the power amplifier in concurrent dual-band signal mode. By taking into account nonlinear memory effects, the new dual-band digital predistortion (DPD) architecture improves the linearization performances of the 2D-Hammerstein model while reducing the complexity compared to the 2D-DPD model. An experimental test bench based on an FPGA is also presented. Linearization and complexity performances are evaluated and compared using a 10W peak power amplifier and a dual-band signal (single-carrier LTE and 3-carrier WCDMA) center frequency spaced by 310MHz. Results show a reduced complexity while achieving similar performances as 2D-DPD. Adjacent channel power ratios (ACPRs) are reduced below -50 dBc and normalized mean square error (NMSE) close to -40 dB.