Partial Transmit Sequence Research Articles

An Improved PAPR Reduction in OFDM Using Discrete Cosine Transform and Partial Transmit Sequence

An Improved PAPR Reduction in OFDM Using Discrete Cosine Transform and Partial Transmit Sequence

Low Complexity PTS and SLM Techniques on PAPR Reduction in SFBC MIMO-OFDM Systems

MIMO-OFDM is an attractive technique for higher data rate transmission and even for fading channels. The signals suffer from high PAPR; it is the drawback of MIMO-OFDM. For ease of accessibility, the MIMO-OFDM systems are employed with SFBC. To reduce the PAPR, the traditional PTS scheme employ directly to every transmitter, but high computational complexity is associated with it. In this paper, the proposed PTS schemes and SLM scheme with QPSK and QAM modulated data are divided into several pairs of blocks based on the way in which original data is divided at two antennas and how each pair of sub-block is modified to generate distinguish pair of new sub different blocks. Thus obtained new sub different blocks are clubbed to induce PTS containing same structure and the diverse potential as of the SFBC. Later, selected sequences having the smaller PAPR are selected and transmitted. Simulated results show, the Type-I PTS scheme and SLM scheme with QPSK modulated data signal have almost similar result which achieves superior PAPR response and Bit Error Rate response when correlated with other schemes with QAM and QPSK modulated signals. Keywords: Peak to Average Power Ratio - PAPR, Partial Transmit Sequences - PTS, Selected Mapping Sequence - SLM, Spatial Frequency Block Code - SFBC

Relatively Evaluation of PAPR Reduction in OFDM Gadget the Use of Iterative Partial Transmit Sequence Set of Rules below Distinctive Modulation Schemes

Relatively Evaluation of PAPR Reduction in OFDM Gadget the Use of Iterative Partial Transmit Sequence Set of Rules below Distinctive Modulation Schemes

Modified PAPR Reduction Scheme by Integrating DCT and WPT with Partial Transmit Sequence

Orthogonal Frequency Division Multiplexing (OFDM) is one of the multicarrier modulation methodology efficiently used for transmission of high data rate in communication system. OFDM consists of number of independent sub carrier, where the peak value of amplitude is high, which is a cause for high Peak to Average Power Ratio (PAPR). Hence unique techniques are proposed for PAPR reduction. Here we have proposed an innovative method by integrating the modified Partial Transmit Sequence (PTS), Discrete Cosine Transformation (DCT) and Wavelet Packet Transform (WPT) in a single system. The simulation results of the proposed system shows significant reduction in the PAPR performance than the ordinary PTS technique. Using our proposed method we have attained noticeable reduction in PAPR without casing imbalance in BER performance of the signal.

PAPR reduction in OFDM system using hybrid PTS-RCMN scheme

Orthogonal Frequency Division Multiplexing (OFDM) is a widely accepted multi-carrier transmission scheme which is used for high data rate applications like Long-Term Evolution (LTE). It offers higher data transmission rate by efficient bandwidth usage. OFDM offers greater resistance and immunity towards inter-symbol interference (ISI) and Inter-Carrier Interference (ICI). However the major drawback associated with OFDM is high Peak to Average Power Ratio (PAPR) which forces high power amplifier (HPA) to work in the non-linear region resulting in harmonic distortions in the output. Partial transmit sequence (PTS) is a widely employed and tested method for PAPR reduction in 4G systems. In this paper we have proposed a novel scheme which uses a combination of PTS and Reduced Complexity Maximum Norm (RCMN) method to improve PAPR reduction performance of PTS system. This scheme has effectively reduced PAPR as compared to conventional PTS technique with insignificant increase in computational complexity.

PTS using novel constellation extension scheme for PAPR reduction of OFDM signals without side information

High peak to average power ratio (PAPR) is a major hindrance in the performance of orthogonal frequency division multiplex (OFDM) systems. When OFDM signal with high PAPR passed through high power amplifiers (HPA), it requires a large back-off to operate in linear region, this leads to large dynamic range of HPA, such HPA are costly and complex with poor efficiency. Partial transmit sequence (PTS) is one of the most promising techniques for PAPR reduction. The major drawback of this technique is it requires exhaustive searching of all possible and allowable phase factors to find the optimal phase factor with lowest PAPR. This information is to be sent to a receiver as side information (SI) for decoding purpose. Sending SI puts additional burden on the transmission bandwidth thus reducing bandwidth efficiency. In this paper, a novel constellation extension-based PTS is proposed which uses novel octagonal geometry (OM-PTS) for mapping purpose. This scheme does not require transmission of any side information for decoding purpose at the receiver. Simulations are presented to show that the proposed scheme provides the same PAPR performance as conventional PTS but without need of SI transmission.

PAPR reduction in OFDM system using hybrid PTS-RCMN scheme

Orthogonal Frequency Division Multiplexing (OFDM) is a widely accepted multi-carrier transmission scheme which is used for high data rate applications like Long-Term Evolution (LTE). It offers higher data transmission rate by efficient bandwidth usage. OFDM offers greater resistance and immunity towards inter-symbol interference (ISI) and Inter-Carrier Interference (ICI). However the major drawback associated with OFDM is high Peak to Average Power Ratio (PAPR) which forces high power amplifier (HPA) to work in the non-linear region resulting in harmonic distortions in the output. Partial transmit sequence (PTS) is a widely employed and tested method for PAPR reduction in 4G systems. In this paper we have proposed a novel scheme which uses a combination of PTS and Reduced Complexity Maximum Norm (RCMN) method to improve PAPR reduction performance of PTS system. This scheme has effectively reduced PAPR as compared to conventional PTS technique with insignificant increase in computational complexity.

PAPR reduction scheme: wavelet packet‐based PTS with embedded side information data scheme

Partial transmit sequence (PTS) is an effective scheme to reduce high peak-to-average power ratio (PAPR) for multicarrier modulation (MCM) signal transmission systems. This approach produces side information (SI) data as a result of the MCM signal optimisation process. The generated SI data are required to be transmitted with the original data over the channel for successful data recovery at the receiver. An effective method for SI data transmission has not yet been identified and research is still ongoing. Hence, the authors introduce a technique that embeds SI data into the original data frame. In this study, a wavelet packet (WP)-based PTS (WP-PTS) scheme is selected as the MCM transmission method. The proposed scheme is called WP-PTS with embedded SI data. In addition, a suitable scheme for reconstructing the original data is developed. Simulation result shows that the PAPR performance of the proposed scheme improves by up to 2.5 dB at a complementary cumulative distribution function level of 10−4 compared with the original WP-orthogonal frequency-division multiplexing system without the PAPR reduction scheme when the number of selected disjoint subblocks is 16.

PAPR Reduction of Multicarrier Faster-Than-Nyquist Signals With Partial Transmit Sequence

Multicarrier faster-than-Nyquist (MFTN) signaling is a spectral efficient transmission scheme for future communication systems. Similar as general multicarrier signals, the high peak-to-average power ratio (PAPR) is also one of the main drawbacks of MFTN signals. Unfortunately, the PAPR problem in MFTN signaling system has rarely been considered in the literatures. In this paper, we investigate the PAPR reduction for MFTN signals. First, we derive an inverse fast Fourier transform (IFFT)-based implementation of the MFTN transmitter. Based on which, a novel partial transmit sequence (PTS) scheme is proposed for the PAPR reduction of MFTN signals. The proposed PTS scheme relies on a two-stage optimization of the phase weighting factors for the parallel IFFT blocks as well as the phase weighting factors for the information symbols before the summation operation. It is shown that the proposed scheme substantially outperforms the direct employment of conventional Nyquist multicarrier transmission systems-based PTS scheme and also robust to the overlap-add operation introduced by pulse shaping.

Peak-to-Average Power Ratio Reduction of FBMC/OQAM Signal Using a Joint Optimization Scheme

Owing to the signal structure difference between the filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) and the orthogonal frequency-division multiplexing (OFDM) systems, the existing technologies to reduce the peak-to-average power ratio (PAPR) for OFDM systems are not suitable for the FBMC/OQAM systems. This paper considers the problem of PAPR in the FBMC/OQAM systems, and to reduce the PAPR of the FBMC/OQAM signal, we propose an improved joint optimization scheme combined with the linear (i.e., partial transmit sequence (PTS)) and nonlinear (i.e., clipping and filtering (CF)) methods, named improved bilayer partial transmit sequence and iterative clipping and filtering (IBPTS-ICF) scheme. The main idea of this joint optimization scheme is clipping and filtering the processed FBMC/OQAM signal, whose probability of the peak value has been reduced by the IBPTS technique. Meanwhile, aided by the knowledge of convex optimization, the IBPTS-ICF joint optimization scheme can effectively reduce the signal distortion. The excellent PAPR reduction performance of the proposed scheme has been confirmed in our simulations.

Low Computational Complexity PTS Scheme for PAPR Reduction of MIMO-OFDM Systems

In the last decade a combination of multiple-input multiple-output (MIMO) with orthogonal frequency division multiplexing (OFDM) has lead to significant advancement in wireless communication systems. It has been receiving a great deal of attention as a solution of high-quality service for next generation. However, one of the main disadvantages of OFDM is, its high Peak-to-Average Power Ratio (PAPR) which leads to more interference and limits power efficiency of High Power Amplifier (HPA). As one of popular and promising scheme, partial transmit sequences (PTS) provides an effective solution for PAPR reduction of OFDM signals, but its exhaustive search of phase factors causes high computational complexity. This paper aims to present a novel method based on PTS, in order to improve the performance in terms of PAPR. In the proposed method, a low computational complexity phase weighting process is employed, where we use one phase {1, or -1, or j, or –j} to optimize the bloc with the maximum PAPR. The simulation results show that the proposed algorithm can not only reduces the PAPR significantly, but also decreases the computational complexity.

PAPR Reduction of Localized Single Carrier FDMA using Partial Transmit Sequence in LTE System

PAPR Reduction of Localized Single Carrier FDMA using Partial Transmit Sequence in LTE System

Hardware co-simulation for a low complexity PAPR reduction scheme on an FPGA

This paper presents a novel low-complexity technique for reducing the Peak-to-Average Power Ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) systems followed by an efficient hardware co-simulation implementation of this technique by using a Xilinx system generator on a Field Programmable Gate Array (FPGA). In this technique, each subblock is interleaved with the others, and a new optimisation scheme is introduced in which the number of iterations is equal only to the number of subblocks, which results in reduced processing time and less computation that, in turn, leads to reduced complexity. Furthermore, the proposed method focuses on simplifying the required hardware resources. Thus, it can be easily combined with other simplified techniques. The simulation results demonstrate that the new technique can effectively reduce the complexity up to 98.22% compared with the new existing Partial Transmit Sequence (PTS) techniques and yield a good Bit Error Rate (BER) performance. Through the comparison of performance between simulation and hardware, it is distinctly illustrated that the designed hardware block diagram is as workable as the simulation and the difference of the result is only 0.1 dB.

Hardware co-simulation for a low complexity PAPR reduction scheme on an FPGA

This paper presents a novel low-complexity technique for reducing the Peak-to-Average Power Ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) systems followed by an efficient hardware co-simulation implementation of this technique by using a Xilinx system generator on a Field Programmable Gate Array (FPGA). In this technique, each subblock is interleaved with the others, and a new optimisation scheme is introduced in which the number of iterations is equal only to the number of subblocks, which results in reduced processing time and less computation that, in turn, leads to reduced complexity. Furthermore, the proposed method focuses on simplifying the required hardware resources. Thus, it can be easily combined with other simplified techniques. The simulation results demonstrate that the new technique can effectively reduce the complexity up to 98.22% compared with the new existing Partial Transmit Sequence (PTS) techniques and yield a good Bit Error Rate (BER) performance. Through the comparison of performance between simulation and hardware, it is distinctly illustrated that the designed hardware block diagram is as workable as the simulation and the difference of the result is only 0.1 dB.

PAPR Reduction in OFDM Systems using Partial Transmit Sequence combined with Cuckoo Search Optimization Algorithm (ICAT16-0286)

Partial transmit sequence (PTS) scheme is one of the efficacious tool for lessening peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) system. However, computational cost for the optimum phase factors searches of PTS scheme entails huge computational requirements and limits its applicability to practical applications especially for high-speed data transmissions. This study proposes a PAPR reduction method with a low computational complexity based on a combination of cuckoo search optimization algorithm with PTS scheme in OFDM system. In terms of PAPR and computational cost reductions, the performance of the cuckoo-PTS scheme is comparatively investigated by performing a set of simulations with different PTS schemes.

N ‐PTS scheme with low complexity for PAPR reduction

Partial transmit sequence (PTS) is a promising technology for peak-to-average power ratio (PAPR) reduction because it introduces no distortion. However, the high computational complexity is the main drawback of PTS scheme. A low-complexity PTS scheme, called N-PTS, is proposed for PAPR reduction. By constructing some sequences, the time-domain signals are obtained by combining the original signal with two circular signals. Thus, only one inverse fast Fourier transform block is required to implement. Analyses and simulation results show that the N-PTS scheme achieves extremely low computational complexity while sacrificing a little bit of performance compared with the conventional PTS.

A novel reduced complexity optimized PTS technique for PAPR reduction in wireless OFDM systems

In this paper, we propose a novel low complexity Partial Transmit Sequence (PTS) technique employing Random phase sequence matrix (RPSM) for peak to average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. The main goal of our suggested scheme is to achieve the optimum phase sequence matrix to minimize PAPR and simultaneously reduce the computational complexity by decreasing the number of Inverse Fast Fourier Transform (IFFT) operations required. Lower PAPR reduces the complexity of Digital to Analog converters (DAC) and increases the efficiency of power amplifiers. Analytical expressions for Complementary Cumulative Distribution Function (CCDF), Number of subcarriers, subblocks and Total computational complexity are derived. Simulation results match closely with the analytical results. It is demonstrated that a favorable tradeoff can be achieved between the reduction of PAPR and computational complexity. It is observed that the suggested modified PTS technique outperforms the traditional PTS (T-PTS) technique.

Peak-to-Average Power Ratio Reduction in Lifting Based Wavelet Packet Modulation Systems Using Differential Evolution Algorithm

Integer wavelet transform (IWT) is an alternative to fast Fourier transform (FFT) in orthogonal frequency division multiplexing (OFDM) systems. It serves implementation flexibility and performance improvement by diminishing high side lobes, sensitivity to time and frequency synchronization. However, high PAPR of the transmitted signals is also a significant problem for IWT as in FFT based OFDM. One of the methods used for reducing the peak-to-average power ratio (PAPR) is partial transmit sequences (PTS) and this method requires an exhaustive search to obtain optimum reduction. This study examines the PAPR reduction potential of differential evolution algorithm based PTS scheme in lifting based wavelet packet modulation (LBWPM) system. The simulation results indicate that remarkable PAPR reduction performance with a low computational load for LBWPM system can be achieved using the proposed differential evolution based PTS scheme.

Uma Abordagem Heurística para o Algoritmo PTS na Redução da PAPR em Sistemas OFDM

Este trabalho analisa a redução da relação entre a potência de pico e potência média (PAPR) em sistemas com multiplexagem por divisão de frequência ortogonal (OFDM) sob a perspectiva da otimização heurística aplicada à topologia de transmissão por sequência parcial, visando a redução de sua complexidade computacional. Uma elevada PAPR em sinais OFDM acarreta em redução da eficiência energética dos amplificadores de alta potência (HPA) presentes no transmissor que, para evitar distorção no sinal amplificado, devem ter seu ponto de operação deslocado reduzindo a potência do sinal de entrada por um nível denominado input back-off (IBO). A técnica de transmissão por sequência parcial(PTS) para redução dos níveis de PAPR foi analisada e avaliada por meio de otimização heurística denominada enxame de partículas (PSO); os resultados foram comparados aos obtidos com o algoritmo PTS convencional (C-PTS) em termos da relação entre complexidade computacional e redução da PAPR obtida. Os resultados numéricos de simulação mostraram que ao utilizar o algoritmo PSOPTS é possível atingir resultados quase-ótimos em aproximadamente um quarto do tempo utilizado pelo C-PTS, tornando o primeiro mais adequado para utilização comercial, que usualmente envolvem sistemas robustos com um elevado número de subportadoras, o que necessariamente implica em uma alta PAPR.

GA-PTS Using Novel Mapping Scheme for PAPR Reduction of OFDM Signals Without SI

In recent time orthogonal frequency division multiplexing (OFDM) has proved its mettle as a preferred choice for high speed transmission in wireless applications due its efficient mechanism to combat the inter symbol interference. However sudden high peaks in OFDM signal envelope lead to high peak to average power ratio (PAPR). Enhanced values of PAPR result into complex RF amplifier circuit with reduced efficiency. There are various methods available for PAPR reduction, out of them partial transmit sequence (PTS) is most effective proven choice for PAPR reduction. However PTS technique requires cumbersome searching of all possible phase factors to find optimal phase factor which produces lowest PAPR, the information regarding optimal phase set used at the transmitter need to be sent to the receiver as side information (SI) for decoding purpose, however transmitting SI requires additional transmission bandwidth thus reducing overall bandwidth efficiency. To reduce the exhaustive searching genetic algorithm (GA) could be used with PTS leading to GA-PTS system. In this paper a GA-PTS system is proposed which uses novel octagonal geometry for constellation extension purpose. This scheme does not require transmission of any side information for decoding purpose at receiver and at the same time GA-PTS system reduces the required number of searches. Simulations are presented to show that proposed scheme provides similar PAPR performance as conventional PTS but without need of SI transmission at reduced number of searches.