Open-loop digital predistorter for RF power amplifiers using dynamic deviation reduction-based Volterra series
Open-loop digital predistorter for RF power amplifiers using dynamic deviation reduction-based Volterra series
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DOI：
10.1109/tmtt.2008.925211
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发表时间：
2008-07-01
影响因子：
4.3
通讯作者：
Asbeck, Peter M.
中科院分区：
文献类型：
--
作者：
Zhu, Anding;Draxler, Paul J.;Asbeck, Peter M.
在本文中，我们提出了一种有效的开环数字预失真器（DPD），该预失真器源自基于动态偏差减少的Volterra系列，可以补偿无线发射机中射频功率放大器引起的非线性失真和记忆效应。在这种方法中，预失真器的参数可以直接从离线系统辨识过程中提取。这消除了通常对闭环实时参数自适应的需求，从而大大降低了系统的实现复杂性。研究表明，在模型提取中应用欠采样理论，在DPD实现中使用参数插值，可以进一步降低系统的复杂性。实验结果表明，利用该技术，在参数较少的情况下，可以显著降低相邻信道功率比，并改善归一化均方根误差。并与基于无记忆多项式函数的预失真器进行了比较，分析了衰减对预失真器的影响。
In this paper, we propose an efficient open-loop digital predistorter (DPD) derived from the dynamic deviation reduction-based Volterra series that allows compensation for both nonlinear distortion and memory effects induced by RF power amplifiers in wireless transmitters. In this approach, the parameters of the predistorter can be directly extracted from an offline system identification process. This eliminates the usual requirement for a closed-loop real-time parameter adaptation, which dramatically reduces the implementation complexity of the system. It is shown that a further reduction in system complexity can be achieved by applying under-sampling theory in the model extraction and utilizing parameter interpolation in the DPD implementation. Experimental results show that by utilizing this technique with only a small number of parameters, nonlinear distortion induced by the PA can be significantly reduced, as evaluated by both adjacent channel power ratio reduction and normalized root mean square error improvement. A comparison with a memoryless polynomial function based predistorter and an analysis of the impact of decresting are also presented.