Nonlinear Distortion Cancellation using Predistorter in MIMO-GFDM Systems

Jayati, Ari Endang; Wirawan, Wirawan; Suryani, Titiek; Endroyono,

doi:10.3390/electronics8060620

Cited by 10 publications

(13 citation statements)

References 34 publications

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“…The next PAPR reduction technique is SLM, as shown in figure 6 with the simulation parameters in Table 2 with SLM parameters, number of symbols, i.e. : 100, Subband count: 64, oversampling factor: 4, number of candidate symbols GFDM (C): 16, permutations Factor Phase (B): 16 x 64. Figure 7 shows that the PAPR for GFDM compared to OFDM before the SLM reduction technique in CCDF 0.01 PAPR GFDM value is about 8.8 dB whereas OFDM is about 8.6 dB.…”

Section: Resultsmentioning

confidence: 99%

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Partial Transmit Sequence and Selected Mapping Schemes for PAPR Reduction in GFDM Systems

Jayati¹,

Wirawan²,

Suryani³

et al. 2019

IJIES

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Generalized Frequency Division Multiplexing (GFDM) is one of the 5G candidates to overcome the shortcomings of Orthogonal Frequency Division Multiplexing (OFDM), high peak rating power ratio (PAPR), and high Out of Band (OOB) radiation. GFDM has a low PAPR due to the use of a number of subcarriers. The purpose of this paper is to compare the two algorithms to reduce PAPR if applied to the non-linear distortion-affected GFDM system. Partial Transmit Sequence (PTS) and Selected Mapping (SLM) are selected because these techniques do not distort the signal, so they do not change the spectrum of the signal. The simulation result shows PAPR GFDM is not significantly affected by nonlinear distortion. After being given the PTS technique, the PAPR value on GFDM dropped to 5 dB. Meanwhile, after being given a selective mapping technique, the PAPR value in GFDM dropped to 6.2 dB.. However, for a 5G application with thousands of devices, this value should still be reduced. After being given a PTS, the PAPR value drops to the value according to the 5G criterion. Better PTS performance decreases PAPR for GFDM systems that are given nonlinear distortion when compared to SLM.

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Section: Resultsmentioning

confidence: 99%

“…Research on the effects of nonlinear distortion on Multiple Input Multiple Output (MIMO)-GFDM systems when signals are passed by HPA has been carried out by [16]. In addition, they also propose methods to overcome these problems.…”

Section: Literature Reviewmentioning

confidence: 99%

Partial Transmit Sequence and Selected Mapping Schemes for PAPR Reduction in GFDM Systems

Jayati¹,

Wirawan²,

Suryani³

et al. 2019

IJIES

Self Cite

View full text Add to dashboard Cite

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“…Regarding this nonlinear aspect, special efforts are needed to investigate the effects of nonlinear distortion produced by RF-PAs, which include amplitude distortion, phase distortion [11], and the spread of signal constellations based on the quasi-memoryless Saleh model when passed through the additive white gaussian noise (AWGN) channel. This model was chosen because it involves the amplitude-to-amplitude (AM/AM) and amplitude-to-phase (AM/PM) conversion curves [12]. Additionally, the need to establish methodologies for transmitting and modeling data primarily with digital multiplexing such as long-term evolution (LTE) and wideband code division multiple access (WCDMA) are of current interest [13], even implementing a two-chain amplifying structure in parallel for the 2.5 GHz band [14].…”

Section: Introductionmentioning

confidence: 99%

A Weighted Linearization Method for Highly RF-PA Nonlinear Behavior Based on the Compression Region Identification

et al. 2021

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In this paper, we present an adaptive modeling and linearization algorithm using the weighted memory polynomial model (W-MPM) implemented in a chain involving the indirect learning approach (ILA) as a linearization technique. The main aim of this paper is to offer an alternative to correcting the undesirable effect of spectral regrowth based on modeling and linearization stages, where the 1-dB compression point (P1dB) of a nonlinear device caused by memory effects within a short time is considered. The obtained accuracy is tested for a highly nonlinear behavior power amplifier (PA) properly measured using a field-programmable gate array (FPGA) system. The adaptive modeling stage shows, for the two PAs under test, performances with accuracies of −32.72 dB normalized mean square error (NMSE) using the memory polynomial model (MPM) compared with −38.03 dB NMSE using the W-MPM for the (i) 10 W gallium nitride (GaN) high-electron-mobility transistor (HEMT) radio frequency power amplifier (RF-PA) and of −44.34 dB NMSE based on the MPM and −44.90 dB NMSE using the W-MPM for (ii) a ZHL-42W+ at 2000 MHz. The modeling stage and algorithm are suitably implemented in an FPGA testbed. Furthermore, the methodology for measuring the RF-PA under test is discussed. The whole algorithm is able to adapt both stages due to the flexibility of the W-MPM model. The results prove that the W-MPM requires less coefficients compared with a static model. The error vector magnitude (EVM) is estimated for both the static and adaptive schemes, obtaining a considerable reduction in the transmitter chain. The development of an adaptive stage such as the W-MPM is ideal for digital predistortion (DPD) systems where the devices under test vary their electrical characteristics due to use or aging degradation.

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“…TWTA and SSPA are generally more advantageous for higher power and higher frequencies, at a reduced size, cost, and with improved thermal performance. Unfortunately, these amplifiers are highly non-linear [15], hence, a large back-off [16] is needed to mitigate the signal distortion. As outcome, the efficiency is substantially reduced.…”

Section: Introductionmentioning

confidence: 99%

Dimensioning an FPGA for Real-Time Implementation of State of the Art Neural Network-Based HPA Predistorter

et al. 2021

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Orthogonal Frequency Division Multiplexing (OFDM) is one of the key modulations for current and novel broadband communications standards. For example, Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM) is an excellent choice for the ECMA-368 Ultra Wideband (UWB) wireless communication standard. Nevertheless, the high Peak to Average Power Ratio (PAPR) of MB-OFDM UWB signals reduces the power efficiency of the key element in mobile devices, the High Power Amplifier (HPA), due to non-linear distortion, known as the non-linear saturation of the HPA. In order to deal with this limiting problem, a new and efficient pre-distorter scheme using a Neural Networks (NN) is proposed and also implemented on Field Programmable Gate Array (FPGA). This solution based on the pre-distortion concept of HPA non-linearities offers a good trade-off between complexity and performance. Some tests and validation have been conducted on the two types of HPA: Travelling Wave Tube Amplifiers (TWTA) and Solid State Power Amplifiers (SSPA). The results show that the proposed pre-distorter design presents low complexity and low error rate. Indeed, the implemented architecture uses 10% of DSP (Digital Signal Processing) blocks and 1% of LUTs (Look up Table) in case of SSPA, whereas it only uses 1% of LUTs in case of TWTA. In addition, it allows us to conclude that advanced machine learning techniques can be efficiently implemented in hardware with the adequate design.

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Nonlinear Distortion Cancellation using Predistorter in MIMO-GFDM Systems

Cited by 10 publications

References 34 publications

Partial Transmit Sequence and Selected Mapping Schemes for PAPR Reduction in GFDM Systems

Partial Transmit Sequence and Selected Mapping Schemes for PAPR Reduction in GFDM Systems

A Weighted Linearization Method for Highly RF-PA Nonlinear Behavior Based on the Compression Region Identification

Dimensioning an FPGA for Real-Time Implementation of State of the Art Neural Network-Based HPA Predistorter

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