Predistortion Algorithm Based on Compressing Quantization for Nonsinusoidal Orthogonal Modulation Signal in Time-domain

Nonsinusoidal orthogonal modulation signal in time-domain has high peak-to-average power ratio, so it is vulnerable to the nonlinearity of power amplifier. To relieve this affection, a non-iterative look-up table predistortion method based on waveform training is presented which can obtain the amplitude and phase modification value fast and corretly. For the reason that the predistortion accuracy is directly associated with the chosen quantization method, a compressing quantization method is presented. The characteristic of power amplifier and the distribution characteristic of signal amplitude are taken considered in this method. The distortion characteristic in band and out of band of signal before and after imploying the presented predistortion method is simulated and compared with the method with equal space. The results show that the presented method can effectively improve the power spectrum of the signal and the bit error rate performance of system, and minish the intermodulated power of signal.