线性插值基的数字预失真方法

随着射频功率放大器的发射功率不断提升,特别是Doherty功放的广泛应用,使得功放的非线性特性不断增强。为了满足高线性化的需求,数字预失真(digital pre distortion, DPD)技术要求达到更优的非线性校正效果。提出一种基于线性插值基的数字预失真方法,所提方法将线性插值基引入到数字预失真的行为建模中,达到优化的非线性校正效果。同时所提方法通过与查找表的实现方式结合,非常利于系统应用。仿真实验中采用20 MHz长期演进(long term evolution, LTE)信号进行实验,新方法较广义记忆多项式方法在临道泄露比指标上改善了近7 dBc以上。

Digital pre-distortion based on linear interpolation basis function

With the output power level becoming higher, especially the wider application of the technique of Dorherty radio frequency power amplifier (PA), the nonlinear characteristics of PA are stronger. In order to meet the high linearization requirements, digital pre distortion (DPD) needs to achieve better performance in nonlinear correction. An approach of the DPD based on linear interpolation basis function is proposed, which introduces the linear interpolation basis function in DPD behavioral modeling to optimize the performance of the nonlinear correction. Meanwhile, combining with the look up table implementation, it is suitable for system applications. The 20 MHz long term evolution (LTE) signal is employed to do simulations. Results show that the proposed approach is almost 7 dBc better than the generalized memory polynomial approach in the adjacent channel leakage ratio.