One-bit in-phase observation for direct learning-based digital predistortion with modified frequency-domain delay estimation and alignment
One-bit in-phase observation for direct learning-based digital predistortion with modified frequency-domain delay estimation and alignment
复制标题
用于基于直接学习的数字预失真的一位同相观测，具有改进的频域延迟估计和对齐
DOI：
10.1002/mmce.21149
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发表时间：
2017
影响因子：
1.7
通讯作者：
Liu Falin
中科院分区：
文献类型：
--
作者：
Zhang Yikang;Wang Haoyu;Li Gang;Liu Falin
提出了一种新的射频功率放大器数字预失真(DPD)实现方法。该方法只在反馈通道中使用一个1比特比较器来观察输入和输出信号之间的误差信号的同相(I)或正交(Q)分量。为此，本文首先将现有的1bit方法与低成本的同相观测相结合，给出了基于直接学习结构(DLA)的同相观测的理论推导。为了便于时延估计和对准，提出了一种改进的迭代频域时延估计方法，该方法只需获取输出信号的I或Q分量即可获得满意的时延估计。实验结果表明，该方法的归一化均方误差和邻道功率比分别小于−42和−51，表明该系统在实现复杂度较低的情况下，可以获得与已有的分布式PD识别技术相当的性能。
This article proposes a novel digital predistortion (DPD) implementation method for RF power amplifiers. The new approach adopts only one 1‐bit comparator in the feedback path to observe the in‐phase (I) or the quadrature (Q) component of the error signal between the input and the output signals. To this end, the theoretical derivation of the in‐phase observation based on direct learning architecture (DLA) DPD is first given in this article, by combining the existing 1‐bit method and the low‐cost in‐phase observation. To facilitate the delay estimation and alignment, a modified iterative frequency‐domain delay estimation is presented, which only acquires either I or Q components of the output signal to achieve satisfied delay estimation. Experimental results show that the proposed DPD method decreased the normalized mean square error (NMSE) and the adjacent channel power ratio (ACPR) to less than −42 and −51 dB, respectively, which indicates that the proposed DPD system can achieve comparable performance as the existing DPD identification techniques with lower implementation complexity.