Legendre wavelet for power amplifier linearization

Power amplifier (PA) plays a key role in transceivers for mobile communication systems and the improvement of the linearity of the PA becomes an objective of first importance. This paper proposes a novel linearization method for PA based on the Legendre wavelet possessing rich properties, so as to this technique combines the advantages of piecewise linear functions and orthogonal polynomials for pre-distortion linearization. Pre-distorter (PD) has been identified and power spectrum also has been compared based on the data of the PA characteristics for WCDMA and OFDM signals, respectively. The computational results demonstrate that a quite significant improvement in linearity is achieved and the PD is stable and effective. The most attractive aspects of the presented method is that the Legendre wavelet bases can approximate static nonlinearity of the PA with different level of resolution and lower order piecewise polynomials than that of other polynomials.