OFDM Peak-to-average Power Ratio Research Articles

Comparison of PAPR Reduction Using ABC-FF Algorithm and OGWO in MIMO-OFDM

In the transmitted signal, the high peak-to-average power ratio (PAPR) is the real disadvantage of multiple input, multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Among different PAPR reduction techniques, selected mapping (SLM) is a famous strategy that accomplishes good PAPR reduction performance without signal distortion. Likewise, Partial transmit sequence (PTS) is additionally solitary of the successful techniques to decrease the PAPR in OFDM. Though, result an optimal segment issue in PTS system is measured to exist a critical concern. To progress the existing PAPR reduction techniques, we have incorporated ideal SLM and PTS based PAPR reduction strategy in parallel. By utilizing, the OGWO algorithm; the transmit succession was chosen with least PAPR above all communication antennas. The proposed PAPR reduction approach is applied independently on each transmitted antenna, and so the PAPR can be extremely reduced. Moreover, the OGWO optimization based PAPR reduction technique will provide better performance and it was been promoted as an uncomplicated way for PAPR reduction. The proposed approach will be analyzed with ABC-FF Algorithm PAPR reduction scheme to show the effectiveness

EVM Closed-Form Expression for OFDM Signals With Tone Reservation-Based PAPR Reduction

Peak to average power ratio (PAPR) reduction of OFDM signals has extensively been studied in the literature. Tone Reservation (TR) is one of the most famous algorithms and has already been included in some digital television standards such as DVB-T2 and ASTC3.0. However, the literature is still lacking theoretical analysis and performance bounds for the PAPR reduction of OFDM signals, especially using TR algorithms. For the first time, this paper provides fundamental results establishing the links between TR-PAPR reduction and the remaining signal distortions at the output of a non-linear high power amplifier (HPA) with and without memory effects. We first derive a generic EVM expression relying on the statistical characteristics of the samples composing the time domain signal and for any PAPR reduction technique. Computing these moments in the case of the quadratically constrained quadratic problem (QCQP) algorithm known as the optimal solution to the TR-PAPR reduction problem allows us to get the lower bound of the EVM of OFDM signals after TR-PAPR reduction and non-linear HPA. As a reference, we also provide the EVM expression using a clipping-based PAPR reduction method. The obtained EVM expressions have direct practical meaning since they are in function of the input power back-off (IBO) applied to the signal before the HPA. They also consist in a general analytical framework for OFDM PAPR reduction since they can be further exploited to analyze the performance of sub-optimal TR-based PAPR reduction algorithms.

PAPR Reduction of OFDM Signal Through DFT Precoding and GMSK Pulse Shaping in Indoor VLC

Optical orthogonal-frequency-division-multiplexing (O-OFDM) has been widely explored for visible light communication (VLC) to achieve high data rates. However, O-OFDM suffers from high peak-to-average power ratio (PAPR), which causes clipping distortion, reduces illumination to communication conversion efficiency and affects the lifetime of the light-emitting diode (LED). This paper proposes a novel modulation technique, an amalgamation of discrete Fourier transform (DFT) precoding and Gaussian minimum shift keying (GMSK) pulse shaping to reduce the PAPR of OFDM based VLC system. Furthermore, the concept of group precoding is also introduced to deal with the increased complexity of the DFT precoding system. The results show that different variants of the proposed scheme provide improved PAPR, symbol-error-rate (SER), and power-saving performance as compared to the corresponding DFT precoded O-OFDM and O-OFDM counterpart. Moreover, the analytical study of PAPR, computational complexity and spectral efficiency for the proposed system have also been investigated and reported in this paper.

Fractional Wavelet Transform based PAPR Reduction Schemes in Multicarrier Modulation System

The future mobile communication system stimulates researcher to improve the spectral efficiency with reduced data loss by carrying out several works. High peak to average power ratio (PAPR) of the transmitted signal is the major drawback in the multicarrier transmission like orthogonal frequency division multiplexing. This study presents a novel way to improve the performance of the multicarrier transmission system with the reduction of PAPR. It is achieved by reconstructing the Fourier-based OFDM block with the help of fractional wavelet transform. This transform provides the accurate joint information of time and fractional frequency contents of the signal which highlights the proposed system. In this system, the wavelet transform is utilized to remove the usage of cyclic prefix and to improve the bandwidth efficiency. In addition, the analysis of PAPR in the FrWT-based OFDM is carried out with the help of selective mapping (SLM) and partial transmit sequences (PTSs) techniques. The simulated results are compared with the existing PAPR analysis of Fourier and wavelet-based OFDM systems. The proposed system shows reduced PAPR of 6.6 dB with SLM scheme and 4.8 dB with PTS scheme to achieve complementary cumulative distribution function of 10−3. The overall performance of the FrWT-OFDM transceiver is analyzed by means of bit error rate (BER) plots and it also shows BER reduction of 0.0028 with SLM scheme and 0.0012 with PTS scheme at high SNR of 16 dB.

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

Abstract In 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.

A Survey on Optimization Based Spectrum Sensing Techniques to Reduce ISI and PAPR in OFDM Based Cognitive Radio System

Cognitive radio is emerging technologies in OFDM based wireless systems which are very important for spectrum sensing. By using cognitive radio (CR) high data can be transferred with low bit error rate. The key idea of OFDM is to split the total transmission bandwidth into the subcarriers which further reduce the intersymbol interference (ISI) and peak to average power ratio(PAPR) in the signal. There are many optimization based spectrum sensing techniques are existing for efficient sensing purpose but each has its own advantages and disadvantages. This leads to start the comprehensive study for reducing PAPR and ISI(Intersymbol interference) in terms of FPGA based partial configuration. In the first part of review OFDM characteristics of the signal has compared with several optimizations based ISI reduction techniques. The second part is to compare the various spectrum sensing techniques in cognitive radio engine and its application in FPGA.

A Survey on Optimization Based Spectrum Sensing Techniques to Reduce ISI and PAPR In OFDM Based Cognitive Radio System

Cognitive radio is emerging technologies in OFDM based wireless systems which are very important for spectrum sensing. By using cognitive radio (CR) high data can be transferred with low bit error rate. The key idea of OFDM is to split the total transmission bandwidth into the subcarriers which further reduce the intersymbol interference (ISI) and peak to average power ratio(PAPR) in the signal. There are many optimization based spectrum sensing techniques are existing for efficient sensing purpose but each has its own advantages and disadvantages. This leads to start the comprehensive study for reducing PAPR and ISI(Intersymbol interference) in terms of FPGA based partial configuration. In the first part of review OFDM characteristics of the signal has compared with several optimizations based ISI reduction techniques. The second part is to compare the various spectrum sensing techniques in cognitive radio engine and its application in FPGA

PAPR Reduction in OFDM

The term OFDM is a special type of FDM which has very vast application in the field of wired and wireless communication systems. In this paper we are discussing about the main problem of OFDM i.e. Peak to Average Power Ratio (PAPR) which affects the performance and efficiency of Power Amplifier. Partial Transmit Sequence (PTS) is an attractive scheme for PAPR reduction without distortion, but to obtain preferable PAPR performance it needs many Inverse Fast Fourier Transforms (IFFTs) which results in high complexity. In this paper, a single IFFT block is implanted in to PTS technique for reduction of PAPR in OFDM. The scheme is very efficient and avoids the use of any extra IFFTs as was done in PAPR reduction by ordinary PTS technique.

A Constrained Optimization Approach to Compander Design for OFDM PAPR Reduction

In this paper, we derive new multi-component companders for reducing peak-to-average power ratio (PAPR) in orthogonal frequency-division multiplexing signals, using a constrained optimization approach. The new companders provide out-of-band power rejection performance improvements over current state-of-the art companders, while maintaining comparable demodulation performance. The newly designed companders are derived by minimally perturbing the Rayleigh signal amplitude distribution, while enforcing the constant power and probability density function constraints. The use of a multi-component approach to compander construction provides design flexibility, and expands the space of tradeoffs between demodulation performance, PAPR reduction, and out-of-band power rejection. Furthermore, the new companders provide solutions in operating regions where certain current companders fail to exist due to violation of one or more constraints; for example, solutions may be derived for cutoff amplitude values that are unobtainable using other companders. We formulate the constrained optimization problem for compander design and derive the compander and decompander forms. Through numerical simulation, we generate performance results demonstrating the capability of the new companders.

GreenOFDM: a new selected mapping method for OFDM PAPR reduction

A new selected mapping orthogonal frequency division multiplexing modulation (SLM-OFDM) that generates symbol candidates using U inverse fast Fourier transform is presented. The complementary cumulative distribution function of peak-to-average power ratio (PAPR) of the so-called GreenOFDM is derived and computer simulations show that the proposed method outperforms any other SLM-OFDM proposed method so far. Also, GreenOFDM is compared with localised single carrier frequency division multiple access as it is a well-known PAPR reduction technique standardised for long-term evolution advanced.

Influence of Pulse Shaping Filters on PAPR Performance of Underwater 5G Communication System Technique: GFDM

Generalized frequency division multiplexing (GFDM) is a new candidate technique for the fifth generation (5G) standard based on multibranch multicarrier filter bank. Unlike OFDM, it enables the frequency and time domain multiuser scheduling and can be implemented digitally. It is the generalization of traditional OFDM with several added advantages like the low PAPR (peak to average power ratio). In this paper, the influence of the pulse shaping filter on PAPR performance of the GFDM system is investigated and the comparison of PAPR in OFDM and GFDM is also demonstrated. The PAPR is restrained by selecting proper parameters and filters to make the underwater acoustic communication more efficient.

PAPR analysis in noncontiguous OFDM systems

AbstractNoncontiguous orthogonal frequency‐division multiplexing (NC‐OFDM) is a modulation technique suitable for 5G communications. It achieves high spectral efficiency due to aggregation and modulation with nonzero data symbols of only nonoccupied spectrum resources (subcarrier blocks). Similarly as in other multicarrier schemes, one of its main drawbacks is the high variation of instantaneous signal power measured typically by means of peak‐to‐average power ratio (PAPR). Although a lot of research effort has been put in OFDM PAPR characterization, there is a need for such work in the case of NC‐OFDM. This paper finds that PAPR distribution of NC‐OFDM is different than in the case of OFDM. The analysis was done by means of both simulations and analytical derivations. Lower and upper PAPR complementary cumulative distribution function bounds are provided for NC‐OFDM that are much tighter than state‐of‐the‐art solutions.

Performance Analysis of PAPR Reduction in 4×4 Spatially Multiplexed MIMO-OFDM System using SLM and Optimum-PTS Techniques

Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is a promising candidate for 4G high-data-rate broadband wireless communications. However, MIMO-OFDM inherited the problem of high Peak-to-Average Power Ratio (PAPR) from OFDM which leads to in-band distortion, undesired spectral spreading, low power efficiency and increases the cost of the RF power amplifier. Many PAPR reduction techniques were developed in last two decades to reduce the PAPR of OFDM, among them Partial Transmit Sequence (PTS) and Selected Mapping (SLM) are the important ones. This paper proposes two PAPR reduction technique; SLM and Optimum -PTS for reducing the PAPR and does performance comparison of these two techniques on the basis of reduction in PAPR level, BER and the number of redundant bits required. It shows that the use of Optimum-PTS technique with QPSK modulation comprising of 128 subcarriers provides better PAPR reduction and good BER as compared to SLM.

Peak to Average Power Ratio Reduction in NC–OFDM Systems

Abstract Non contiguous orthogonal frequency division multiplexing (NC-OFDM) is an efficient and adaptable multicarrier modulation scheme to be used in cognitive radio communications. However like OFDM, NC-OFDM also suffers from the main drawback of high peak to average power ratio (PAPR). In this paper PAPR has been reduced by employing three different trigonometric transforms. Discrete cosine transform (DCT), discrete sine transform (DST) and fractional fourier transform (FRFT) has been combined with conventional selected level mapping (SLM) technique to reduce the PAPR of both OFDM and NC-OFDM based systems. The method combines all the transforms with SLM in different ways. Transforms DCT, DST and FRFT have been applied before the SLM block or inside the SLM block before IFFT. Simulation results show the comparative analysis of all the transforms using SLM in case of both OFDM and NC-OFDM based systems.

PAPR Reduction of OFDM Signal via Custom Conic Optimized Iterative Adaptive Clipping and Filtering

High peak to average power ratio (PAPR) of OFDM reduces the transmitter power efficiency and increases the complication in hardware implementation. A number of techniques have been developed to minimize PAPR of OFDM. Among these techniques, iterative clipping and filtering (ICF) is an effective recent technique that produces significant results in minimizing PAPR. But, the major limitation of this approach is that it requires several iterations for minimizing PAPR. In order to overcome the above limitation, an optimization based ICF is used in this research work. An efficient custom optimized adaptive clipping and filtering technique is proposed. The proposed method shows a greater reduction in PAPR in lesser iterations with reduced out-of-band distortion and bit error rate when compared over classical clipping techniques. Moreover, the effects of oversampling on the performance of the proposed OFDM system are also evaluated.

OFDM PAPR Reduction by Shifting Null Subcarriers Among Data Subcarriers

This proposed method reduces the peak-to-average power ratio (PAPR) of multi-carrier transmission, by exploiting null-subcarriers. Compared with the Partial Transmit Sequence Simulated Annealing (PTS-SA) method, the proposed method yields better PAPR reduction performance while consuming the same computation complexity and less channel side information (CSI). The proposed method also demonstrates better bit-error-rate (BER) performance and much lower computation complexity than Null-Switching when CSI is available. Meanwhile, our method is compatible with the current commercial systems and can incorporate with most other PAPR-reduction methods (such as partial transmit sequences, selective mapping, tone injection, trellis shaping).

An efficient designed prototype technique for OFDM PAPR reduction using FPGA

SUMMARYIn this paper, a proposed designed technique to reduce OFDM peak‐to‐average power ratio (PAPR) value is performed. This designed technique contains a new block, which is inserted in the OFDM system. This proposed block is applied to the WiMAX system as an example of the OFDM technology. Afterwards, several MATLAB programs are executed to discuss the behavior and the characteristics of this proposed block. In addition, the effect of its insertion on the original system is studied. Because of this insertion, 0‐dB OFDM PAPR value can be achieved. Furthermore, it can be synthesized practically. This proposed system is implemented over a field‐programmable gate array (FPGA). The designed circuit is characterized by both its low complexity and its high speed. Moreover, it is a portable circuit. This means that it can be implemented over any FPGA kit regardless of its technology. Copyright © 2012 John Wiley & Sons, Ltd.

Dynamic null-data subcarrier switching for OFDM PAPR reduction with low computational overhead

A computationally efficient null-data subcarrier switching scheme for peak-to-average power ratio (PAPR) reduction of OFDM systems is proposed. By applying incremental searching within dynamically expanding subcarrier bands, the proposed method achieves significant reduction in computational requirement without sacrificing PAPR reduction capability. The effectiveness of the proposed scheme is demonstrated by presenting simulation results of PAPR and bit error ratio.

OFDM PAPR reduction by switching null subcarriers and data-subcarriers

This proposed method reduces the peak-to-average power ratio (PAPR) of multi-carrier transmission, by exploiting null subcarriers, already mandated in most OFDM wireless standards. This new approach requires no channel side information, can be compatible with existing standards, imposes no rate hit, is distortionless, has low computational complexity, and can complement most other PAPR-reduction methods (such as active constellation extension, partial transmit sequences, selective mapping, tone injection, tone reservation).

A New Effective and Efficient Measure of PAPR in OFDM

In multi-carrier wireless OFDM communication systems, a major issue is related to high peaks in transmitted signals, resulting in such problems as power inefficiency. In this regard, a common practice is to transmit the signal that has the lowest Peak to Average Power Ratio (PAPR). Consequently, some efficient and accurate method of estimating the PAPR of a signal is required. Previous literature in this area suggests a strong relationship between PAPR and Power Variance (PV). As such, PV has been advocated as a good measure of PAPR. However, contrary to what is suggested in the literature, our research shows that often low values of PV do not correspond to low values of PAPR. Hence, PV does not provide a sound scientific basis for comparing and estimating PAPR in OFDM signals. In this paper a novel, effective, and efficient measure of high peaks in OFDM signals is proposed, which is less complex than PAPR. The proposed measure, termed as Partial Power Variance (PPV), exploits the relationship among PAPR, Aperiodic Autocorrelation Co-efficient (AAC), and Power Variance (PV) of the transmitted signal. Our results demonstrate that, in comparison to PV, Partial Power Variance is a more efficient as well as a more effective measure of PAPR. In addition, we demonstrate that the computational complexity of PPV is far less than that of PAPR.