Complexity and numerical stability investigation in concurrent dual-band modeling of ultra-wideband power amplifiers for harmonically related signals

2D curtailed harmonic memory polynomial for reduced complexity in concurrent dual‐band modelling and digital predistortion with the second band at harmonic frequency

“…Let us consider two modulated complex baseband input signals x 1 and x 2 being transmitted at carrier frequencies ω 1 = αω and ω 2 = βω respectively, where α, β ∈ ℤ + and α ≠ β. As illustrated in [20,25], the 2D-MP model is not sufficient to capture harmonic interferences terms of ultra-wideband PA. For this scenario, the 2D-HMP model is proposed in [20] to capture the harmonic interferences and model the PA output. The outputs of this model are given as…”

“…To further reduce the matrix size, PCA as defined in [25] is applied on both the 2D-HMP and 2D-CHMP models, and termed as 2D-HMP-PCA and 2D-CHMP-PCA. PCA also improves the numerical stability of the model.…”

“…In [24], PCA-based effective single-band DPD technique for low-bit FPGA implementation was proposed. In [25], the PCA technique was applied upon the 2D-HMP model to reduce the number of coefficients, size of observation (predistorter) matrix, condition number and dispersion coefficient. The reduction in condition number and dispersion coefficient provides a measure for the numerical stability of the model.…”