scholarly journals A Novel Signal Scrambling Technique for PAPR Reduction in OFDM Systems

2019 ◽  
Vol 8 (9S) ◽  
pp. 767-770
Keyword(s):  
Performance Improvement ◽  
Average Power ◽  
Signal Amplitude ◽  
Ofdm Systems ◽  
Linear Region ◽  
Ofdm Signal ◽  
Efficient Performance ◽  
Data Rates ◽  
Modulation Type ◽  
Simulation Results

OFDM forms the basis of the upcoming next generation technologies so as to achieve higher data rates within a given bandwidth effectively. One of the major issues associated with OFDM is Peak to Average Power Ratio (PAPR) which needs to be minimized to get an efficient performance. The random variation in the signal amplitude of the OFDM signal leads to additional interference in the system and hence affecting the performance of HPA in non-linear region. In this paper, we propose a technique for the reduction of PAPR in OFDM systems with some increased complexity which works for any modulation type and any number of subcarriers. The simulation results show performance improvement with respect to the existing signal scrambling techniques

scholarly journals Optimized Adaptive Huffmann Coding For Paper Reduction in OFDM Systems

2013 ◽  
Vol 2 (04) ◽  
pp. 13-18
Author(s):  
Dr. Atul Suryavanshi
Keyword(s):  
Average Power ◽  
High Peak ◽  
Huffman Coding ◽  
Power Ratio ◽  
Ofdm Systems ◽  
Main Defect ◽  
Simulation Results

The main defect of OFDM systems is its high peak-to-average power ratio (PAPR). To decrease PAPR, Adaptive Huffman coding is essential. Encoding is transferred by two encoding techniques Huffman coding and Adaptive Huffman coding at the transmitter side. Mapping is done by QAM 16 and PSK 16.The PAPR results of Huffman and adaptive Huffman coding with QAM 16 and PSK 16 is compared. Simulation results shows that the Adaptive Huffman coding along with QAM 16 produces fruitful results in comparison with Huffman coding and adaptive Huffman coding with PSK 16.

Generalized Trapezoidal Companding Technique for PAPR Reduction in OFDM Systems

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Saruti Gupta ◽  
Ashish Goel
Keyword(s):  
Bit Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Frequency Division ◽  
Performance Parameters ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Ofdm Signal ◽  
Specific Degree ◽  
Ofdm Signals

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.

Analysis of secured Optical Orthogonal Frequency Division Multiplexed System

2017 ◽  
Vol 38 (2) ◽  
Author(s):  
Harsimranjit Singh Gill ◽  
Kamaljit Singh Bhatia ◽  
Sandeep Singh Gill
Keyword(s):  
Signal To Noise Ratio ◽  
Average Power ◽  
Single Mode ◽  
Optical Signal ◽  
Data Encryption ◽  
Single Mode Fiber ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm Signal ◽  
Coded Ofdm

AbstractIn this paper, security issues for optical orthogonal frequency division multiplexed (OFDM) systems are emphasized. The encryption has been done on the data of coded OFDM symbols using data encryption standard (DES) algorithm before transmitting through the fiber. The results obtained justify that the DES provides better security to the input data without further bandwidth requirement. The data is transmitted to a distance of 1,000 km in a single-mode fiber with 16-quadrature amplitude modulation. The peak-to-average power ratio and optical signal-to-noise ratio of secure coded OFDM signal is fairly better than the conventional 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.

scholarly journals PAPR Reduction Performance by Active Constellation Extension for Diversity MIMO-OFDM Systems

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Theodoros Tsiligkaridis ◽  
Douglas L. Jones
Keyword(s):  
Average Power ◽  
Block Code ◽  
Papr Reduction ◽  
Ofdm Systems ◽  
Broadband Wireless ◽  
Communication Architecture ◽  
High Data ◽  
Data Rates ◽  
Mimo Ofdm ◽  
Systems Simulation

The V-BLAST wireless communication architecture, space-time block code (STBC), and space-frequency block code (SFBC) techniques are strong candidates for achieving very high data rates in 4G broadband wireless communications. This paper extends the efficient Active Constellation Extension Smart Gradient-Project (ACE-SGP) peak-to-average power (PAPR) reduction method to STBC, SFBC, and V-BLAST systems. Simulation results show 4.19 and 3.57 dB of PAPR reduction for the Alamouti STBC and SFBC, respectively.

scholarly journals Design of an Adaptive Predistorter for Solid State Power Amplifier in Wireless OFDM Systems

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Rui J. P. de Figueiredo ◽  
Lin Fang ◽  
Byung Moo Lee
Keyword(s):  
Performance Improvement ◽  
Power Amplifier ◽  
Communication Systems ◽  
Power Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Wireless Communication Systems ◽  
Ofdm Systems ◽  
High Power Amplifier ◽  
Ofdm Signals

Orthogonal frequency division multiplexing (OFDM) is a powerful modulation choice for wideband wireless communication systems. However, its high peak-to-average power ratio greatly limits the high power amplifier (HPA) power efficiency. Here, we present the design of an adaptive predistorter to compensate the distortion caused by the HPA. Specifically, we deal with the implementation issue of the proposed predistorter in Lee and de Figueiredo's work (2006). The performance improvement by predistorter is verified by both floating-point simulation and fixed-point simulation, where the latter includes the distortion effects from the hardware. The bit widths for OFDM signals, ADC, and DAC are evaluated, and the bit width of 10 is shown to be sufficient for the hardware design.

Understanding Peak Average Power Ratio in VFFT-OFDM Systems

2015 ◽  
Vol 776 ◽  
pp. 419-424 ◽  
Author(s):  
N.M.A.E.D. Wirastuti
Keyword(s):  
Distribution Function ◽  
Cumulative Distribution Function ◽  
Statistical Approach ◽  
Average Power ◽  
Cumulative Distribution ◽  
Power Ratio ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Complementary Cumulative Distribution Function ◽  
Simulation Results

This paper describes an impairment commonly encountered in an OFDM system that must be considered in the design that is peak average power ratio (PAPR). In these studies, a statistical approach to analysing PAPR is suggested. The PAPR statistics of OFDM and VFFT-OFDM are studied by simulation of the statistical distribution of the quantity that is the Complementary Cumulative Distribution Function (CCDF) of the PAPR. The simulation results show that the simulated CCDF of PAPR, the 1% PAPR of OFDM is about 11.40 dB, whereas for VFFT-OFDM this rises to less than 3% of the time. Simulations show that by employing VFFT in OFDM system results in a 0.55 dB deterioration in the PAPR 1% of time.

PAPR Reduction in OFDM System Using Hybrid OICF and Phase Rotation Scheme

2019 ◽  
Vol 40 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Richa Bhatia ◽  
Vivek Upadhyay
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Papr Reduction ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Linear Region ◽  
High Power Amplifier ◽  
Phase Rotation ◽  
Rotation Scheme

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.

scholarly journals Simple Receiving Scheme Based on Balanced Detection for Half-Cycled SSB DD-OFDM Signal

2020 ◽  
Author(s):  
Pengfei Yang ◽  
Xue Chen
Keyword(s):  
Phase Noise ◽  
Orthogonal Frequency Division Multiplexing ◽  
Potential Benefit ◽  
Average Power ◽  
Frequency Division Multiplexing ◽  
Guard Band ◽  
Ofdm Signal ◽  
Channel Interference ◽  
Simulation Results ◽  
Balanced Detection

In this letter, we proposed a simple balanced-detection reception scheme for the half-cycled single-sideband direct-detected optical orthogonal frequency division multiplexing (HSSB DD-OFDM) signal with decreased guard band. By employing this scheme, each entire OFDM symbol can be recovered perfectly, while the signal-to-signal beat interference (SSBI) can be eliminated, the guard band can be reduced greatly and the tolerance to phase noise induced inter-channel interference (PN-ICI) and potential benefit of low peak to average power (PAPR) are retained. The simulation results demonstrate that a 40 Gbps 16-QAM HSSB DD-OFDM signal was achieved successfully.

scholarly journals Estudio y simulación de técnicas para reducir la PAPR en HACO-OFDM

2021 ◽  
Vol 9 (17) ◽  
pp. 40-55
Author(s):  
Evelyn Nathaly Bermeo Granda ◽  
Diego Javier Reinoso Chisaguano
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
Convex Sets ◽  
Average Power ◽  
Electromagnetic Spectrum ◽  
Visible Light Communications ◽  
Ofdm Systems ◽  
High Data ◽  
Data Rates ◽  
High Spectral Efficiency

VLC (Visible Light Communications) have been recently proposed as a new form of wireless communications. The VLC advantages are its usage of the spectrum of visible light which is not licensed; additionally, it gives high data rates, protects the user against espionage and does not suffer from interference of the electromagnetic spectrum. One of the main techniques used in VLC is HACO-OFDM (Hybrid Asymmetrically Clipped Optical - Orthogonal Frequency Division Multiplexing), which offers a high spectral efficiency. However, one of its main problems is its high PAPR (Peak-to-Average-Power Ratio). This article presents a study and simulation of Clipping, CE-POCS (Constellation Extension – Project Onto Convex Sets), OPS (Orthogonal Pilot Sequences) and SAP (Simple Amplitude Predistortion) techniques for the reduction of the PAPR in HACO-OFDM systems. The simulation results show that the SAP technique gives the best results in PAPR reduction without significant degradation in the BER (Bit Error Rate).

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