This paper presents a low sampling rate digital pre-distortion technique based on an improved Chebyshev polynomial for the non-linear distortion problem of amplifiers in 5G broadband communication systems.An improved ...This paper presents a low sampling rate digital pre-distortion technique based on an improved Chebyshev polynomial for the non-linear distortion problem of amplifiers in 5G broadband communication systems.An improved Chebyshev polynomial is used to construct the behavioural model of the broadband amplifier,and an undersampling technique is used to sample the output signal of the amplifier,reduce the sampling rate,and extract the pre-distortion parameters from the sampled signal through an indirect learning structure to finally correct the non-linearity of the amplifier system.This technique is able to improve the linearity and efficiency of the power amplifier and provides better flexibility.Experimental results show that by constructing the behavioural model of the amplifier using memory polynomials(MP),generalised polynomials(GMP)and modified Chebyshev polynomials respectively,the adjacent channel power ratio of the obtained system can be improved by more than 13.87d B,17.6dB and 19.98dB respectively compared to the output signal of the amplifier without digital pre-distortion.The Chebyshev polynomial improves the neighbourhood channel power ratio by 6.11dB and 2.38dB compared to the memory polynomial and generalised polynomial respectively,while the normalised mean square error is effectively improved and enhanced.This shows that the improved Chebyshev pre-distortion can guarantee the performance of the system and improve the non-linearity better.展开更多
In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF li...In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously sup-pressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is ob-tained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in lin-earization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.展开更多
Digital PreDistortion(DPD)is a very useful method to improve the linearity of Power Amplifiers(PAs)for LTE and upcoming 5 G networks.As the spectrum resources are becoming more and more crowded,and the communications ...Digital PreDistortion(DPD)is a very useful method to improve the linearity of Power Amplifiers(PAs)for LTE and upcoming 5 G networks.As the spectrum resources are becoming more and more crowded,and the communications bandwidth are broader,the ACPR(Adjacent Channel Leakage Ratio)is very important to communication systems.DPD is one of the useful means for PA to reduce ACPR.This article demonstrates what DPD is and how DPD is achieved,the measurement of the Digital Distortion of a PA using a vector generator and vector analyzer,and the measurement results has been discussed.展开更多
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...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20MHz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7dBc以上。展开更多
文摘This paper presents a low sampling rate digital pre-distortion technique based on an improved Chebyshev polynomial for the non-linear distortion problem of amplifiers in 5G broadband communication systems.An improved Chebyshev polynomial is used to construct the behavioural model of the broadband amplifier,and an undersampling technique is used to sample the output signal of the amplifier,reduce the sampling rate,and extract the pre-distortion parameters from the sampled signal through an indirect learning structure to finally correct the non-linearity of the amplifier system.This technique is able to improve the linearity and efficiency of the power amplifier and provides better flexibility.Experimental results show that by constructing the behavioural model of the amplifier using memory polynomials(MP),generalised polynomials(GMP)and modified Chebyshev polynomials respectively,the adjacent channel power ratio of the obtained system can be improved by more than 13.87d B,17.6dB and 19.98dB respectively compared to the output signal of the amplifier without digital pre-distortion.The Chebyshev polynomial improves the neighbourhood channel power ratio by 6.11dB and 2.38dB compared to the memory polynomial and generalised polynomial respectively,while the normalised mean square error is effectively improved and enhanced.This shows that the improved Chebyshev pre-distortion can guarantee the performance of the system and improve the non-linearity better.
基金Supported by the National Natural Science Foundation of China (No. 60972064)
文摘In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously sup-pressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is ob-tained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in lin-earization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.
基金supported by Shenzhen Strategic Emerging Industry Development Fund Project——Public service platform for 5G key components testing(20170921165224440)
文摘Digital PreDistortion(DPD)is a very useful method to improve the linearity of Power Amplifiers(PAs)for LTE and upcoming 5 G networks.As the spectrum resources are becoming more and more crowded,and the communications bandwidth are broader,the ACPR(Adjacent Channel Leakage Ratio)is very important to communication systems.DPD is one of the useful means for PA to reduce ACPR.This article demonstrates what DPD is and how DPD is achieved,the measurement of the Digital Distortion of a PA using a vector generator and vector analyzer,and the measurement results has been discussed.
文摘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20MHz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7dBc以上。
