Instantaneous Sample Indexed Magnitude-Selective Affine Function-Based Behavioral Model for Digital Predistortion of RF Power Amplifiers

Li, Yue; Cao, Wenhui; Zhu, Anding

doi:10.1109/tmtt.2018.2855134

Cited by 44 publications

(24 citation statements)

References 19 publications

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“…Digital pre-distortion (DPD) was then applied to correct the non-linearity of the proposed DPA at the same frequency. The linearity performance was measured using the Magnitude-Selective Affine (MSA) function model [28] and the proposed DPA was linearized with a closed-loop estimator. With DPD, the ACPR was improved from -35.3/-32.3 dBc to -53.6/-53.7 dBc at 3.2 GHz as shown in Fig.…”

Section: B Measurement Results With Modulated Signalsmentioning

confidence: 99%

Bandwidth Enhancement of Doherty Power Amplifier Using Modified Load Modulation Network

Pang

et al. 2020

IEEE Trans. Circuits Syst. I

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A novel Doherty power amplifier (DPA) architecture with extended bandwidth is presented in this paper. A modified load modulation network is introduced to provide impedance condition required by the Doherty operation in a wide frequency range. Analytical parameter solutions of the proposed load modulation network and the related load modulation process are presented. A DPA with 2.80-3.55 GHz bandwidth utilizing commercial GaN transistors is implemented. The fabricated DPA attains a measured 9.3-11.1 gain and 43.0-45.0 dBm saturated power. 50.0-60.6% and 66-78% drain efficiency is obtained at 6 dB output power back-off and saturation throughout the designed band, respectively. Moreover, the back-off drain efficiencies are higher than 55% within 700 MHz bandwidth. When driven by a 6-carrier 120 MHz OFDM signal with 7.0 dB peak to average power ratio, the proposed DPA achieves adjacent channel leakage ratio of better than-50 dBc after digital pre-distortion (DPD) at 3.20 GHz with average efficiency of 53.3%.

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Section: B Measurement Results With Modulated Signalsmentioning

confidence: 99%

Bandwidth Enhancement of Doherty Power Amplifier Using Modified Load Modulation Network

Pang

et al. 2020

IEEE Trans. Circuits Syst. I

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“…Afterwards, the extracted coefficients were applied to the precoded signals for the next iteration. For DPD, magnitude-selective affine (MSA) model [6] with M = 4 and K = 6 was considered.…”

Section: Measured Resultsmentioning

confidence: 99%

OTA-Based Data Acquisition and Signal Separation for Digital Predistortion of Multi-User MIMO Transmitters in 5G

Wang

et al. 2020

2020 IEEE/MTT-S International Microwave Symposium (IMS)

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In this paper, a non-interruptive over-the-air (OTA) data acquisition method is presented to characterize system nonlinearity and calibrate digital predistortion (DPD) in multiuser (MU) multiple-input multiple-output (MIMO) transmitters with low hardware complexity. Based on a unified system model for fully-digital and hybrid MU-MIMO transmitters, the requirements and difficulties of data acquisition for MU-MIMO DPD are outlined first. A versatile OTA data acquisition technique, featuring a multi-observation forward modelling procedure, is thereby developed to obtain power amplifier (PA) output without interrupting the operation of the MIMO transmitters. By using this method, the output of each PA can be reconstructed instead of directly measuring each PA's output, even when the output signals of PAs are correlated. DPD can therefore be effectively constructed to mitigate the distortion. Experimental results demonstrate that the proposed approach can accurately estimate each PA output and linearize all PAs in the array.

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“…Various DPD models have been proposed to compensate the nonlinearities of RF PAs [5]- [10]. Volterra-based models such as memory polynomial (MP) model [5], generalized memory polynomial (GMP) model [6] are the most widely used ones.…”

Section: Lots Of Linearization Methods Have Been Developed To Balancementioning

confidence: 99%

“…where W PRB hf , W PRB hi , W PRB ho and W PRB hg are new weight matrices for the previous hidden state. Then, the output of the LSTM cell composed of all the hidden neurons' outputs, can be obtained as (10) and (11). After phase recovery and magnitude extraction operations, the current hidden state h PRB n that will be transmitted to the next time step and I/Q components I out (n), Q out (n) of final output can be calculated.…”

Section: Simplified Vector Decomposed Long Short-term Memory Modelmentioning

confidence: 99%

Vector Decomposed Long Short-Term Memory Model for Behavioral Modeling and Digital Predistortion for Wideband RF Power Amplifiers

Zhang

et al. 2020

IEEE Access

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This paper proposes two novel vector decomposed neural network models for behavioral modeling and digital predistortion (DPD) of radio-frequency (RF) power amplifiers (PAs): vector decomposed long short-term memory (VDLSTM) model and simplified vector decomposed long short-term memory (SVDLSTM) model. The proposed VDLSTM model is a variant of the classic long short-term memory (LSTM) model that can model long-term memory effects. To comply with the physical mechanism of RF PAs, VDLSTM model only conducts nonlinear operations on the magnitudes of the input signals, while the phase information is recovered by linear weighting operations on the output of the LSTM cell. Furthermore, this study modifies the LSTM cell by adding phase recovery operations inside the cell and replacing the original hidden state with the output magnitudes that are recovered with phase information. With the modified LSTM cell, a low-complexity SVDLSTM model is proposed. The experiment results show that the proposed VDLSTM model can achieve better linearization performance compared with the state-of-the-art models when linearizing PAs with wideband inputs. Besides, in wideband scenarios, SVDLSTM model with much fewer parameters can present comparable linearzation performance compared to VDLSTM model. INDEX TERMS Nonlinear power amplifier, behavioral modeling, digital predistortion, neural network, long short-term memory, vector decomposed.

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Instantaneous Sample Indexed Magnitude-Selective Affine Function-Based Behavioral Model for Digital Predistortion of RF Power Amplifiers

Cited by 44 publications

References 19 publications

Bandwidth Enhancement of Doherty Power Amplifier Using Modified Load Modulation Network

Bandwidth Enhancement of Doherty Power Amplifier Using Modified Load Modulation Network

OTA-Based Data Acquisition and Signal Separation for Digital Predistortion of Multi-User MIMO Transmitters in 5G

Vector Decomposed Long Short-Term Memory Model for Behavioral Modeling and Digital Predistortion for Wideband RF Power Amplifiers

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