Windowing Techniques for Reducing PAPR of OFDM in Li-Fi Systems

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Ayad Atiyah Abdulkafi ◽  
Ibrahim Khalil Sileh ◽  
Saad Mshhain Hardan
Keyword(s):  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
Dynamic Range ◽  
Average Power ◽  
Nonlinear Behavior ◽  
Papr Reduction ◽  
Time Domain Signal ◽  
Ofdm Signal ◽  
Nonlinear Distortions ◽  
Ber Performance

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.

Companding Schemes for Reducing PAPR in OFDM System: A Review

2020 ◽  
Vol 41 (3) ◽  
pp. 331-338
Author(s):  
Ashish Goel ◽  
Prateek Mathur
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Design Parameters ◽  
Papr Reduction ◽  
High Data ◽  
System A ◽  
Ofdm Signal ◽  
Two Parameters ◽  
Ofdm Signals ◽  
Ber Performance

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.

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
Keyword(s):  
Neural Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Papr Reduction ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Reduction Scheme ◽  
Ofdm Signal ◽  
Artificial Neural Network Ann ◽  
Ber Performance

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.

scholarly journals PAPR reduction in OFDM system for DVB-S2

2020 ◽  
Vol 17 (1) ◽  
pp. 317
Author(s):  
Zainab M Abid ◽  
Awatif A Jaffaar ◽  
Suha Q Hadi
Keyword(s):  
Fading Channels ◽  
Power Amplifier ◽  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Average Power ◽  
Multipath Fading ◽  
Papr Reduction ◽  
Major Drawback ◽  
Ofdm Signal

<p>A special form of multicarrier modulation is Orthogonal Frequency Division Multiplexing (OFDM) which is offer high spectral efficiency for high speed data transmission through multipath fading channels. Many advantages can be achieved by using OFDM in addition to spectral efficiency like its robustness against intersymbol interference and multipath effect. One of a major drawback of OFDM is high Peak-to-Average Power Ratio (PAPR) of the transmitted signal which leads to a distortion in the power amplifier and causes decreasing the efficiency of power amplifier. To reduce PAPR of OFDM signal many of promising solutions have been proposed and implemented. In this paper, a joint Low Density Parity Check code (LDPC), Discrete Cosine Transform (DCT) and μ-law companding is proposed to reduce PAPR of OFDM signal at transmitter. Comparison of these PAPR reduction techniques is done based on CCDF performance of the system.</p>

Improved Clipping Technique for PAPR Reduction in OFDM

2014 ◽  
Vol 548-549 ◽  
pp. 1420-1423
Author(s):  
M.R. Anjum ◽  
M.A. Shaheen ◽  
Farhan Manzoor ◽  
Mussa A. Dida
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Average Power ◽  
Multipath Fading ◽  
Papr Reduction ◽  
Major Drawback ◽  
Multipath Fading Channel ◽  
Peak Magnitude ◽  
Ofdm Signal ◽  
Clipping Technique

Multicarrier modulation technique also known as Orthogonal Frequency Division Multiplexing (OFDM) is considered to be the most rapidly growing technique for 4th Generation wireless communication system. Due to its high speed data rate and its ability of multipath fading channel robustness. OFDM becomes an attractive technique and it is widely adopted in many wireless communications system. OFDM signal carries its major drawback of high Peak to Average Power Ratio (PAPR) problem. Out of band radiation and in band distortion produced due to its high PAPR. Mobile phone communication suffer severe drawback during its amplification. When OFDM employed a non linear Power Amplifier (PA), it produces the fluctuation in amplitude of OFDM signal. This paper discusses the method to overcome PAPR in terms of its performance by using improved clipping technique for PAPR reduction. This method is easy to implement and reduces the amount of PAPR by clipping the peak of the maximum power signal. We present an improved method for PARR reduction for reducing peak magnitude of OFDM signal. This scheme simultaneously minimizes the peak magnitude of PAPR in OFDM signal.

scholarly journals A New-Trend Model-Based to Solve the Peak Power Problems in OFDM Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Ashraf A. Eltholth ◽  
Adel R. Mekhail ◽  
A. Elshirbini ◽  
M. I. Dessouki ◽  
A. I. Abdelfattah
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Peak Power ◽  
Dynamic Range ◽  
Average Power ◽  
Problem Definition ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Ofdm Signal ◽  
Nonlinear Amplifier ◽  
Power Problem

The high peak to average power ration (PAR) levels of orthogonal frequency division multiplexing (OFDM) signals attract the attention of many researchers during the past decade. Existing approaches that attack this PAR issue are abundant, but no systematic framework or comparison between them exists to date. They sometimes even differ in the problem definition itself and consequently in the basic approach to follow. In this paper, we propose a new trend in mitigating the peak power problem in OFDM system based on modeling the effects of clipping and amplifier nonlinearities in an OFDM system. We showed that the distortion due to these effects is highly related to the dynamic range itself rather than the clipping level or the saturation level of the nonlinear amplifier, and thus we propose two criteria to reduce the dynamic range of the OFDM, namely, the use of MSK modulation and the use of Hadamard transform. Computer simulations of the OFDM system using Matlab are completely matched with the deduced model in terms of OFDM signal quality metrics such as BER, ACPR, and EVM. Also simulation results show that even the reduction of PAR using the two proposed criteria is not significat, and the reduction in the amount of distortion due to HPA is truley delightful.

PAPR Reduction Using Huffman Coding Combined with Selective Interleaver for OFDM Transmitter

2011 ◽  
Vol 145 ◽  
pp. 489-493
Author(s):  
H.A. Hamada ◽  
Usama S. Mohammed ◽  
Moon Kyou Song
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Radio Channel ◽  
Average Power ◽  
Large Data ◽  
Huffman Coding ◽  
Papr Reduction ◽  
Power Ratio ◽  
Time Domain Signal ◽  
Reduction Techniques ◽  
Power Ratio Reduction

Orthogonal Frequency Division Multiplexing (OFDM) technique is becoming the chosen modulation technique for wireless communications. OFDM can provide large data rates with sufficient robustness to radio channel impairments. There are two main drawbacks with OFDM, the peak to average power ratio and its sensitivity to frequency errors. The signal peak to average power ratio reduction solution play an important role to improve performance of OFDM that peak occurs after symbols fed to FFT to produce time domain signal, adding signals up coherently. In This paper we proposes technique to reduce the PAPR using Huffman coding combined with selective interleaver as distortion less scrambling technique. We utilize the amount saved in the total bit rate by the Huffman coding to send the information of the selected interleaver and encoding table for accurate decoding at the receiver without reducing the effective throughput. Performed computer simulations have shown that the proposed scheme outperform the performance of most of the recent PAPR reduction techniques in most cases. By using this method 2.63 dB PAPR reduction is achieved.

PAPR reduction scheme for optical OFDM techniques

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ompal Singh ◽  
Rajeev Paulus ◽  
Rajiv Srivastava
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Optical Fiber Communication ◽  
Papr Reduction ◽  
Channel Noise ◽  
Optical Wireless ◽  
Fiber Communication ◽  
Optical Ofdm ◽  
The Mathematical Model ◽  
Ber Performance

AbstractIn both optical wireless and optical fiber communication, orthogonal frequency division multiplexing (OFDM) plays an important role in data transmission. In the similar context, DC-coupled optical (DCO) OFDM and asymmetrically clipped optical (ACO) OFDM are discussed. DCO-OFDM has better peak to average power ratio (PAPR) but bit error rate (BER) performance is poor; however, in case of ACO-OFDM, PAPR is poor but BER performance is good. Moreover, DCO-OFDM is more power hungry; therefore, ACO-OFDM is considered as a preferred choice. Recently, asymmetrically clipped DC-biased optical (ADO)-OFDM is proposed, which shows good PAPR and BER performance. Clipping and µ-law companding techniques are discussed for PAPR reduction. The mathematical model is developed for all the three methods for received signal while considering clipping and companding noises along with channel noise. It is found that ADO-OFDM is better choice in comparison to DCO and ACO-OFDM. However, in case of ADO-OFDM, receiver structure is more complex.

Hadamard Transform Combined with PTS for PAPR Reduction in Direct-Detection Optical OFDM System

2014 ◽  
Vol 1061-1062 ◽  
pp. 1194-1197
Author(s):  
Hui Li ◽  
Xu Zhang ◽  
Lei Guo ◽  
Ye Jun Liu ◽  
Xiao Xue Gong ◽  
...  
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Direct Detection ◽  
Average Power ◽  
Papr Reduction ◽  
Hadamard Transform ◽  
Ofdm System ◽  
Partial Transmit Sequence ◽  
Ofdm Signal ◽  
Optical Ofdm ◽  
Complementary Techniques

High Peak-to-Average Power Ratio (PAPR) of the Orthogonal Frequency Division Multiplexing (OFDM) signal is one of the limitations to the transmission performance of optical OFDM system. In this paper, we propose a novel hybrid PAPR reduction technique called Hadamard Transform Combined with Partial transmit sequence (HTCP). The proposed HTCP scheme combines the merits of two complementary techniques, i.e., Hadamard transform and Partial Transmit Sequence (PTS), to improve the performance of the optical OFDM system in terms of PAPR and Bit Error Rate (BER). Simulation results show that the HTCP scheme has better performance with regard to PAPR and BER compared with the case of applying only the Hadamard transform or PTS technique.

A Novel Nonlinear Companding Transform for PAPR Reduction in Lattice-OFDM System

Frequenz ◽  
2014 ◽  
Vol 68 (9-10) ◽  
Author(s):  
Siming Peng ◽  
Yuehong Shen ◽  
Zhigang Yuan ◽  
Wei Jian ◽  
Yuwei Miao
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Selection Criteria ◽  
Average Power ◽  
Papr Reduction ◽  
Frequency Division ◽  
Ofdm System ◽  
Distribution Form ◽  
Design Flexibility ◽  
Probability Density Function Pdf ◽  
Ber Performance

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

scholarly journals New technique combining the Tone Reservation method with Clipping technique to reduce the Peak-to-Average Power Ratio

2018 ◽  
Vol 8 (6) ◽  
pp. 5215
Author(s):  
Hajar Abdelali
Keyword(s):  
Power Amplifier ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Papr Reduction ◽  
Power Ratio ◽  
Gain Compression ◽  
Nonlinear Distortions ◽  
Comparison Results ◽  
Tone Reservation ◽  
Linear Power Amplifier

Nonlinear distortions and impairments appear in multicarrier signal with high fluctuations when amplified by a Radio Frequency Power Amplifier (RF PA). Clipping (CL) technique offers a simple way to reduce these fluctuations in Orthogonal Frequency Division Multiplexing (OFDM) Technique, but may degrade seriously the transmission quality. This is why the new mobile standards propose other methods, like the Tone Reservation (TR) technique in the Digital Video Broadcasting-Terrestrial (DVB-T), that reduce the Peak-to-Average Power Ratio (PAPR) without reaching optimal performances. This paper deals with how we can use the TR technique, which exploits null sub-carriers for generating corrective signal, in combining to CL technique in order to improve PAPR reduction without data loss. Also, we show some comparison results on the PAPR reduction obtained with proposed scheme and other techniques. Experiments using a simulated example on a complete WiMax 802.16e transmitter have been made in order to investigate the PAPR reduction performances on presence of the non-linear Power Amplifier model based on gain compression response and phase distortion.

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