scholarly journals A Novel PAPR Reduction Scheme for OFDM Systems Based on Neural Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Feng Zou ◽  
Zhijun Liu ◽  
Xin Hu ◽  
Gang Wang

Orthogonal frequency division multiplexing (OFDM) is extensively applied in the downlink of narrowband Internet of Things (NB-IoT). However, the high peak-to-average power ratio (PAPR) of OFDM systems leads to a decrease in transmitter efficiency. Therefore, the researchers proposed the artificial neural network (ANN) based PAPR reduction schemes. However, these schemes have the disadvantages of high complexity or cannot overcome the defects of traditional schemes. In this paper, a novel PAPR reduction scheme based on neural networks (NNs) is proposed for OFDM systems. This scheme establishes a PAPR reduction module based on NN, which is trained using the low PAPR data obtained by the simplified clipping and filtering (SCF) method. To overcome the defect of poor BER performance of the SCF scheme, a recovery module is introduced at the receiver, to recover the distorted signal. To realize the improvement of BER performance and the reduction of PAPR simultaneously, the two modules are jointly trained based on multiobjective optimization. Experimental results based on a 100 MHz OFDM signal show that this scheme can reduce PAPR by 4.5 dB. Meanwhile, the BER of this scheme can be reduced to 0.001 times that of the SCF scheme.

Author(s):  
PRITANJALI KUMARI ◽  
US TRIAR

Orthogonal Frequency Division Multiplexing (OFDM), widely used in digital wireless communication, has a major drawback of high Peak to Average Power Ratio (PAPR). A reduced complexity partial transmit sequence (PTS) scheme has been proposed to solve high peak to average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) system. In the proposed PTS scheme, a function is generated by summing the power of time domain samples at time ‘n’ in each sub blocks, known as “Hn”.Only those samples, having Hn greater than or equal to a preset threshold value (αT) are used for peak power calculation during the process of selecting a candidate signal with the lowest PAPR for transmission. As compared to conventional PTS scheme, the proposed scheme achieves almost the same PAPR reduction performance with much lower computational complexity.


2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Saruti Gupta ◽  
Ashish Goel

Abstract The main drawback in the performance of the Orthogonal Frequency Division Multiplexing (OFDM) system is the higher Peak-to-Average Power Ratio (PAPR) of the OFDM signals at the transmitter side. Companding is a well-known technique useful for reducing PAPR in the OFDM signal. This paper proposes a new nonlinear companding scheme that transforms the magnitude of Rayleigh distributed OFDM signal of specific degree into trapezoidal distribution. Additional design parameter is used in the proposed companding scheme to make the companding function more flexible. In the designed OFDM system the companding function has more degree of freedom which improves the PAPR and bit error rate (BER) parameters of the designed system. It has been demonstrated that the designed companding scheme provides more flexibility to accomplish an optimum trade-off between the performance parameters PAPR and BER of the designed OFDM system.


Information ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 190 ◽  
Author(s):  
Brahim Bakkas ◽  
Reda Benkhouya ◽  
Idriss Chana ◽  
Hussain Ben-Azza

Orthogonal frequency division multiplexing (OFDM) is the key technology used in high-speed communication systems. One of the major drawbacks of OFDM systems is the high peak-to-average power ratio (PAPR) of the transmitted signal. The transmitted signal with a high PAPR requires a very large linear range of the Power Amplifier (PA) on the transmitter side. In this paper, we propose and study a new clipping method named Palm Clipping (Palm date leaf) based on hyperbolic cosine. To evaluate and analyze its performance in terms of the PAPR and Bit Error Rate (BER), we performed some computer simulations by varying the Clipping Ratio (CR) and modulation schemes. The obtained results show that it is possible to achieve a gain of between 7 and 9 dB in terms of PAPR reduction depending on the type of modulation. In addition, comparison with several techniques in terms of PAPR and BER shows that our method is a strong alternative that can be adopted as a PAPR reduction technique for OFDM-based communication systems.


2020 ◽  
Vol 41 (3) ◽  
pp. 331-338
Author(s):  
Ashish Goel ◽  
Prateek Mathur

AbstractHigh PAPR poses a large hindrance to high data rate Orthogonal Frequency Division Multiplexing (OFDM) signals. A companding transform converts the Probability distribution function (PDF) of the transmitted OFDM signal in a way which reduces the Peak-to-average power-ratio (PAPR). In this paper, we have performed the study of companding techniques and analyzes the PAPR and BER performances of these schemes. Here, we have considered μ-law companding, exponential companding, trapezoidal companding (TC) and trigonal companding for comparison. In this paper, we have demonstrated that μ-law companding, exponential companding and trigonal companding schemes have no adaptability in designing the companding function, and along these lines an exchange off between BER performance and PAPR reduction ability is unrealistic to accomplish. However, TC scheme has two parameters (a and b) to design the companding function and hence a trade-off between PAPR reduction capability and BER performance is possible to achieve. BER performance and PAPR reduction capabilities of the scheme under consideration are evaluated and compared through computer simulations. We have also presented an approach to obtain the minimum BER and PAPR of TC and found out the values of design parameters (a and b) for which TC scheme has minimum BER and PAPR.


2018 ◽  
Vol 1 (1) ◽  
pp. 87
Author(s):  
Mohsen Kazemian

<p>Three of the most important techniques of Peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems are Partial Transmit Sequence PAPR (PTS-PAPR), Selected Mapping PAPR (SLM-PAPR) and Cross-Correlation-PTS. This paper performs a complete analysis on these three techniques providing simulation and discussion of their performance on PAPR reduction and bit error rate (BER). Moreover, the comparison of these methods by using Saleh model amplifier in an OFDM system is provided. The results show that PTS-PAPR outperforms the Cross-Correlation-PTS in terms of PAPR performance while Cross-Correlation-PTS method is more efficient in BER reduction compared to PTS-PAPR and SLM-PAPR.</p>


Frequenz ◽  
2014 ◽  
Vol 68 (9-10) ◽  
Author(s):  
Siming Peng ◽  
Yuehong Shen ◽  
Zhigang Yuan ◽  
Wei Jian ◽  
Yuwei Miao

AbstractIn this paper, a novel companding scheme is proposed to reduce the peak-to-average power ratio (PAPR) of lattice orthogonal frequency division multiplexing (LOFDM) system. By transforming the statistics of original signals into a specified distribution form, which is defined by a continuous sine function, this scheme can achieve a simple companding form as well as an improved PAPR and bit-error-rate (BER) performance. Moreover, by introducing the variable companding parameters in the desired probability density function (PDF), a great design flexibility in the companding form and an effective trade-off between the PAPR reduction and BER performance can be achieved to satisfy various system demands. The general formulas of the proposed scheme are derived and a theoretical analysis regarding the achievable transform gain and the selection criteria of companding parameters are also conducted. Simulation results show that the proposed scheme can substantially outperform the conventional


2012 ◽  
Vol 443-444 ◽  
pp. 340-346
Author(s):  
Lin Chen ◽  
Xue Long Hu

Orthogonal Frequency Division Multiplexing (OFDM) has been focused on in high-data-rate wireless communication research. But the high Peak-to-Average Power Ratio (PAPR) is one of the main obstacles to limit wide applications of OFDM. In this paper, based on the definition of the PAPR in OFDM systems, these techniques on PAPR reduction are presented, including signal distortion, signal scrambling, and block coding. The advantages and disadvantages of these techniques are discussed in detail and some performances are achieved by Monte Carlo simulations.


2019 ◽  
Vol 40 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Richa Bhatia ◽  
Vivek Upadhyay

Abstract Peak to average power ratio (PAPR) is one of the major limitations of orthogonal frequency division multiplexing (OFDM) systems because the higher PAPR induces the signal to get out of linear region of high power amplifier (HPA). In this article, a hybrid PAPR reduction scheme based on the combination of optimized iterative clipping and filtering (OICF) method and phase rotation is proposed. Using phase rotation, signal’s initial PAPR has been reduced by 14.23 dB and then OICF further reduces the final PAPR by 1.37 dB. Decreased PAPR will play an important role in reducing systems power consumption.


2019 ◽  
Vol 9 (5) ◽  
pp. 852 ◽  
Author(s):  
Lili Hao ◽  
Dongyi Wang ◽  
Yang Tao ◽  
Wenyong Cheng ◽  
Jing Li ◽  
...  

End-to-end learning in optical communication systems is a promising technique to solve difficult communication problems, especially for peak to average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. The less complex, highly adaptive hardware and advantages in the analysis of unknown or complex channels make deep learning a valid tool to improve system performance. In this paper, we propose an autoencoder network combined with extended selected mapping methods (ESLM-AE) to reduce the PAPR for the DC-biased optical OFDM system and to minimize the bit error rate (BER). The constellation mapping/de-mapping of the transmitted symbols and the phase factor of each subcarrier are acquired and optimized adaptively by training the autoencoder with a combined loss function. In the loss function, both the PAPR and BER performance are taken into account. The simulation results show that a significant PAPR reduction of more than 10 dB has been achieved by using the ESLM-AE scheme in terms of the complementary cumulative distribution function. Furthermore, the proposed scheme exhibits better BER performance compared to the standard PAPR reduction methods.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Ayad Atiyah Abdulkafi ◽  
Ibrahim Khalil Sileh ◽  
Saad Mshhain Hardan

AbstractIn this paper, Li-Fi system based on orthogonal frequency division multiplexing (Li-Fi-OFDM) is presented. In these systems, light-emitting diodes (LEDs) are used to send information data using intensity modulation. LEDs have a limited dynamic range and the voltage-current characteristic shows a nonlinear behavior. Li-Fi-OFDM signal is used to drive these transmitter LEDs. However, LEDs chip overheating and nonlinear distortions occur, due to high peak-to-average power ratio (PAPR) of the OFDM signal. The proposed approach develops a new PAPR reduction method of OFDM in Li-Fi systems based on time-domain windowing techniques. Several windows such as rectangular, Hanning and raised cosine methods have been applied to the OFDM time-domain signal in order to reduce its PAPR while maintain acceptable bit error rate (BER) performance at receiver side. The simulation results of the work have shown the advantages of the offered method; the proposed scheme achieves a significant PAPR reduction compare to the unwindowed signals. Our proposed system also slightly improves the BER performance for all windowing methods employed.


Sign in / Sign up

Export Citation Format

Share Document