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).

scholarly journals Experimental Demonstration of Zadoff–Chu Matrix Transform Precoding for MIMO-OFDM Visible Light Communications

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Xinyue Guo ◽  
Chuxian Wang ◽  
Wei Wang
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
Forward Error Correction ◽  
Average Power ◽  
Visible Light Communication ◽  
Potential Candidate ◽  
Visible Light Communications ◽  
Ofdm Systems ◽  
Experimental Demonstration ◽  
Mimo Ofdm

Visible light communication (VLC) based on a light-emitting diode (LED) is considered to be a potential candidate for the next-generation communication. In this paper, a novel Zadoff–Chu matrix transform (ZCT) precoding is proposed to improve the performance of the traditional space-time block coding- (STBC-) based multiple-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) system. Compared with the existing orthogonal circulant matrix transform (OCT) precoding scheme, the proposed ZCT precoding achieves a much lower peak-to-average power ratio (PAPR) while maintaining the advantage of the uniform signal-to-noise ratio (SNR), which reduces the performance loss caused by LED nonlinearity. To study the system performance further, we set up an experimental demonstration to verify performance improvement under the condition of different driving peak-to-peak voltages (Vpps) and direct current (DC) offsets. Experimental results show that ZCT precoding gains the best bit error rate (BER) performance compared with the traditional and the OCT precoding MIMO-OFDM systems, whose BER is always below the 7% pre-forward error correction (pre-FEC) threshold of 3.8 × 10−3.

scholarly journals Spectrally efficient multicarrier modulation system for visible light communication

2019 ◽  
Vol 9 (2) ◽  
pp. 1184
Author(s):  
T. Deepa ◽  
Harshita Mathur ◽  
K. A. Sunitha
Keyword(s):  
Visible Light ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Reliability ◽  
Visible Light Communication ◽  
Coded Modulation ◽  
High Data ◽  
Delta Sigma ◽  
Trellis Coded ◽  
High Spectral Efficiency ◽  
Trellis Diagram

<span lang="EN-US">Visible Light Communication (VLC) has become an accolade to its radio frequency counterpart. In VLC system, orthogonal frequency division multiplexing (OFDM) has drawn much attention, because of simple equalization, high spectral efficiency, high data rate and robustness to intersymbol interference (ISI). Besides, there are emerging applications that ought to be gotten with low latency and high reliability. To diminish power requirements with no transmission capacity extension, Trellis coded modulation (TCM) is utilized as a part of the framework in which the free distance of trellis diagram is equivalent to the minimum distance between the points of constellation focuses in partitioned subsets, which augments the coding gain up i.e. the performance parameter viably. TCM together with VLC-OFDM enhances the transmission execution in reasonable frameworks. In this paper, we propose OFDM which is based on TCM and is planned and exeuted for digitized OFDM frameworks by presenting delta sigma modulation (DSM) considering VLC channel. Simulation results show that the proposed TCM based VLC-OFDM offers incredible robustness against noises and nonlinear degradation.</span>

scholarly journals A Novel Transceiver Model for Polar Transform Optical (PTO-) OFDM for Visible Light Communication (VLC) Based on Peak to Average Power Ratio Reduction using Precoding

2020 ◽  
Vol 9 (10) ◽  
pp. 307-315
Keyword(s):  
Visible Light ◽  
Power Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Light Emitting Diode ◽  
Average Power ◽  
Visible Light Communication ◽  
Intensity Modulation ◽  
Power Ratio ◽  
Positive Real ◽  
High Data

Indoor visible light communication (VLC) has the potential of providing high data rates for short-range wireless communication with a relative spatial elevated security in contrast to a radiofrequency wireless one. To support that high data stream, Orthogonal Frequency Division Multiplexing (OFDM) is used; however, due to the limited operational bandwidth of the commercial white light-emitting diode (LED), signal processing techniques are used to increase the efficiency of the OFDM and to adapt OFDM to VLC systems. As a major concern, the intensity modulation direct detection necessary for VLC requires positive real signal, this is dealt with by imposing Hermitian pre-possessing or Cartesian to polar conversion post-processing to the OFDM. The use of the Cartesian to polar converter allows the transmission of complex OFDM symbols through the intensity modulation channel. A polar transform optical (PTO-) OFDM presented here as an improvement and simplification of previous polar optical OFDM schemes gives an efficient transceiver architecture. Nevertheless, both OFDM transmission techniques for Visible optical links, similar to radiofrequency (RF), suffer greatly from irregular excessive Peak-to-Average power ratio (PAPR). Higher PAPR reduces the power efficiency of the On-Off Keying (OOK) based on pulse amplitude modulation (PAM). Furthermore, it also is recommendable to reduce the PAPR for conformity with eye safety. A precoding technique is proposed to reduce the PAPR of intensity-modulated for direct detectability of the OFDM signal destined for the wireless optical link using Cartesian-to-Polar conversion. Based on the enhanced processing at the front ends and using MATLAB simulation, it is proven that the presented model can improve the link parameters including the bit error rate (BER) and signal to noise ratio (SNR) and bandwidth efficient compared to Hermitian modified ones.

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.

Effect of Controlling Parameters of Tone Reservation Based on Null Subcarriers (TRNS) on the Performance of OFDM Systems

2020 ◽  
Vol 12 (2) ◽  
pp. 45-62
Author(s):  
Mohamed Mounir ◽  
Mohamed Bakry El Mashade
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Threshold Value ◽  
Papr Reduction ◽  
Ofdm Systems ◽  
Peak Reduction ◽  
High Data ◽  
Tone Reservation ◽  
Number Of Iterations

High data rate communication systems usually implement Orthogonal Frequency Division Multiplexing (OFDM) to face frequency selectivity. High Peak to Average Power Ratio (PAPR) is an OFDM disadvantage that causes Bit Error Rate (BER) degradation and out-of-band (OOB) radiation when OFDM signal pass through nonlinear Power Amplifier (PA). In order to overcome this problem larger Input Back-Off (IBO) is required. However, large IBO decreases the PA efficiency. PAPR reduction techniques are used to reduce the required IBO, so that PA efficiency is saved. Several PAPR reduction methods are introduced in literature, among them Tone Reservation based on Null Subcarriers (TRNS) is downward compatible version of Tone Reservation (TR) with small excess in the average power and low computational complexity compared to others. As will be shown, TRNS is the best practical one of the four downward compatible techniques. Performance of TRNS is controlled by three parameters; number of peak reduction tones (PRTs), predefined threshold (Amax), and number of iterations (Itr). In order to increase PAPR reduction gain, enhance BER performance, and reduce the required IBO to follow the given power spectral density (PSD), we have to choose the values of these parameters adequately. Results showed that, we have to reduce the threshold value to the average (i.e. Amax =0 dB). Also, we have to increase number of PRTs. However, we have to maintain the spectrum shape. Finally, we have to choose moderate number of iterations (e.g. Itr ≈50), as excessive increase in number of iterations is not useful, especially at high PAPR values.

Techniques for PAPR Reduction in OFDM Systems

2012 ◽  
Vol 443-444 ◽  
pp. 340-346
Author(s):  
Lin Chen ◽  
Xue Long Hu
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Papr Reduction ◽  
Signal Distortion ◽  
Frequency Division ◽  
Communication Research ◽  
Ofdm Systems ◽  
High Data ◽  
Advantages And Disadvantages ◽  
Definition Of

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.

Design and Simulation of OFDM for BPSK, QPSK and QAM with Peak Power Reduction Using Clipping Technique

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Arun Kumar
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Peak Power ◽  
Average Power ◽  
Power Reduction ◽  
Frequency Division ◽  
Ofdm System ◽  
High Data ◽  
Data Rates ◽  
Peak Power Reduction ◽  
Clipping Technique

AbstractDue to the increase in demand for high data rates in mobile communication, orthogonal frequency division multiplexing (OFDM) system is employed in many applications. It efficiently overcomes the effect of Inter-symbol Interference caused due to the fading of the channel, but Peak to Average Power Ratio (PAPR) is unitary of the disadvantages in OFDM System. In the stage-I, the OFDM system is designed with different modulation schemes like QAM-16, BPSK, and QPSK. In the latter stage, we work on the reduction of PAPR by using a clipping technique and we establish a significant reduction in PAPR as compared to the conventional clipping technique.

MINIMIZING HIGH PAPR IN OFDM SYSTEM USING CIRCULANT SHIFT CODEWORD

2016 ◽  
Vol 78 (2) ◽  
Author(s):  
Ezmin Abdullah ◽  
Azlina Idris ◽  
Azilah Saparon
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Signal Distortion ◽  
Ofdm Systems ◽  
Ofdm System ◽  
High Data ◽  
Distortion Energy ◽  
Db Difference ◽  
Selective Mapping ◽  
Ofdm Signals

Orthogonal Frequency Division Multiplexing (OFDM) has been widely used in various high data rate wireless communications standards. The high peak-to-average power ratio (PAPR) has however been known to be a constant problem in OFDM systems. The high PAPR in the OFDM system has led to many problems such as signal distortion, energy spilling to the adjacent channel and reducing system performance gradually. In this paper, a technique involving the manipulation of codeword using circulant shift will be introduced. The key idea of the proposed technique is to generate scramble data sequences like the conventional selective mapping (SLM) technique. The simulation results showed that the proposed technique overcame original OFDM signals and conventional SLM with a 19.5% improvement and 1.1 dB difference from conventional SLM. Besides that, the proposed technique offered a lower computationally complexity where the number of IFFT blocks can be reduced by about 57% as compared to conventional SLM.  

scholarly journals Efficient T-OOFDM System to Mitigate the Dispersion of Long-Haul Optical Fiber Channel at Wans

2018 ◽  
Vol 25 (3) ◽  
pp. 5-11
Author(s):  
Mohammed Shweesh Ahmed
Keyword(s):  
Fiber Optics ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Single Mode ◽  
Single Mode Fiber ◽  
High Data ◽  
Data Rates ◽  
Fiber Channel ◽  
Transmitted Signal ◽  
Channel Dispersion

Due to its attractive features, the utilization of fiber optics as a transmission medium with various applications is increased rapidly. In despite, when signals are transmitted with high data rates through ultra-long haul distances of single-mode fiber (SMF), which is usually used at wide area networks (WANs), the nonlinear dispersion of signals is raised. This phenomenon leads digital pulses to interfere with the adjacent pulses. In this paper, an optical orthogonal frequency division multiplexing based T-transform (T-OOFDM) system is proposed to mitigate the effect of fiber dispersion significantly and reduce the peak-to-average power ratio (PAPR) of the transmitted signal when compared with conventional optical OFDM (OOFDM) system. Simulations results confirmed by the analytical analysis demonstrated that the detrimental effects arising from fiber channel dispersion on the subcarrier orthogonality of the transmitted signals can be efficiently minimized by using T-OOFDM system. Moreover, the peak of the transmitted signal will be considerably reduced whilst preserving the average power of signals.

scholarly journals Median codeword Shift (MCS) technique for PAPR reduction with low complexity in OFDM system

2019 ◽  
Vol 9 (6) ◽  
pp. 4882
Author(s):  
Mohd Danial Rozaini ◽  
Azlina Idris ◽  
Darmawaty Mohd Ali ◽  
Ezmin Abdullah
Keyword(s):  
Computational Complexity ◽  
Communication Technology ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rapid Development ◽  
Average Power ◽  
Low Complexity ◽  
Papr Reduction ◽  
Frequency Division ◽  
High Data ◽  
Data Rates

With the rapid development of today’s communication technology, the need for a system capable to improve spectral efficiency, high data rates and at the same time can reduce inter-symbol interference (ISI) is necessary. Orthogonal Frequency Division Multiplexing (OFDM) meet all the requirements needed. However, the high peak to average power ratio (PAPR) has become its major obstacle. This paper is focusing on the development of Median Codeword Shift (MCS), which a new PAPR reduction technique with the capability to reduce the computational complexity of the system. This can be achieved through codeword structure alterization and bit position manipulation by utilizing the circulant shift process. The simulation results revealed that the proposed technique overwhelm conventional OFDM and SCS with 24% improvement and 0.5 dB gap from SCS. In fact, the proposed technique possess a lower computational complexity by reducing 16.67% of the use of IFFT block in the system in contrast with SCS technique.

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