Adaptive Linearization for Power Amplifier in OFDM Systems

An adaptive predistortion linearization is proposed to compensate for the nonlinearity and memory effects of power amplifiers (PAs) in orthogonal frequency division multiplexing (OFDM) communication systems. By using a simplified Volterra series model (VSM) to express the uncertain nonlinear input-output dynamics of PA with a Wiener-Hammerstein structure, an adaptive predistorter is generated directly without identification of inverse model of the PA. When OFDM signals pass through the cascade system of the predistorter and the PA, overall linearization from predistorter input to PA output can be achieved. The effectiveness of the proposed predistortion method is validated by numerical simulation for 64-ary quadrature amplitude modulation OFDM (64QAM-OFDM) transmission systems