An improved LUT based DPD technique for nonlinear HPA in ATSC DTV system

It is well known that high power amplifier (HPA) induces nonlinear distortion around its saturation region. It causes the inter-modulation distortion (IMD) and spectrum re-growth problems. Thus, the digital pre-distortion (DPD) technique is used to improve the linearity of HPA. This paper proposes the adaptive DPD technique, which is composed of a look-up table (LUT) based adaptive update algorithm, for the compensation of HPA nonlinearity. From the simulation results, the proposed technique shows the better convergence speed and spectrum re-growth suppression compared with conventional LUT technique.