用于5G RF PA线性化的多频段通用数字预失真器  

A Multi-band Universal Digital Pre-distorter for Linearizing 5G RF Power Amplifier

作　　者：方俊 叶焱[1] 苏日娜 刘太君[1] 许高明[1,2] FANG Jun;YE Yan;SU Ri-na;LIU Tai-jun;XU Gao-ming(Faculty of Electrical Engineering and Computer Science,Ningbo University,Ningbo 315211,China;National KeyLabof Millimeter Waves,Nanjing 210096,China)

机构地区：[1]宁波大学信息科学与工程学院,宁波315211 [2]毫米波国家重点实验室,南京210096

出　　处：《微波学报》2022年第6期90-94,共5页Journal of Microwaves

基　　金：国家自然科学基金(U1809203,62071264);国家重点实验室开放基金(6142807200107);浙江省自然科学基金(LY21F010004,LQ18F010008);浙江省省属高校基本科研业务费专项资金(SJLY2020013)。

摘　　要：文中提出了一种基于独热编码与长短时期记忆(LSTM)神经网络的多频段通用数字预失真非线性模型,它可以有效地对工作在多个频段的宽带射频功放进行线性化。在训练集中引入表示不同频率信号的不同独热编码,训练后的神经网络非线性模型可以在不改变网络结构和模型参数的情况下对不同频段的功率放大器进行预失真线性化。为了验证该方法的有效性,建立了两个分别工作于2.6 GHz和4.9 GHz的射频功放实验平台,在这两个频段预失真非线性建模的归一化均方误差(NMSE)均可达到-40 dB,然后使用100 MHz带宽5G NR信号,分别对这两个射频功放进行预失真线性化实验验证。实验结果表明,该多频段通用数字预失真器可以将这两个功放的邻信道泄漏比(ACLR)在中心频率下偏100 MHz处分别改善19.42 dB和17.91 dB,在中心频率上偏100 MHz处分别改善15.73 dB和15.17 dB,验证了所提非线性模型的有效性。This paper proposes a multi-band universal digital predistorter model based on one-hot coding and long-short term memory(LSTM)neural network,which can effectively linearize broadband RF power amplifiers working in multiple frequency bands.By introducing different one-hot codes in the training set to represent signals of different frequencies,the trained neural network can be applied to power amplifier linearization of different bands without changing the network structure and model parameters.To verify the effectiveness of the method,an experimental platform with two RF power amplifiers working at 2.6 GHz and 4.9 GHz respectively is established.The normalized mean square error(NMSE)for predistortion nonlinear modeling can reach-40 dB for the two frequency bands.Then,a 100 MHz bandwidth 5G NR signal is used to verify the linearization performance of the method for the two-band power amplifiers.Experiments show that the multiband universal digital predistorter can improve the adjacent channel leakage ratio(ACLR)of the two power amplifiers by 19.42 dB and 17.91 dB respectively at 100 MHz below the center frequency,and 15.73 dB and 15.17 dB respectively at 100 MHz above the center frequency,which verifies the effectiveness of the proposed nonlinear model.

关 键 词：第五代无线通信系统 功率放大器 数字预失真器 长短时期记忆神经网络 独热编码 

分 类 号：TN929.5[电子电信—通信与信息系统]