Partial Transmit Sequence Scheme Research Articles

A hybrid approach based on companding and PTS methods for PAPR reduction of 5G waveforms

ABSTRACT As a crucial enabler for the fifth-generation air interface, the filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) is being investigated by several researchers. This article suggests using partial transmit sequence (PTS) and companding to create a hybrid peak-to-average power ratio (PAPR) reduction strategy for FBMC/OQAM signals. In the novel PTS Companding scheme, there are several segments to the data block signal, and the overlapping factor determines the number of data blocks in each segment. To obtain the lowest signal power in each segment, we choose the best data block to broadcast and examine the next overlapping data block concurrently. After that, the segment FBMC/OQAM signal peaks are compressed using companding. Based on simulation results and analysis, the proposed hybrid PTS Companding method in FBMC/OQAM systems may reduce PAPR more effectively than conventional PTS and Companding schemes. According to simulation results, the hybrid process can achieve around 5 dB greater PAPR performance than the conventional PTS and companding schemes.

A Permutated Partial Transmit Sequence Scheme for PAPR Reduction in Polar-Coded OFDM-IM Systems

A Permutated Partial Transmit Sequence Scheme for PAPR Reduction in Polar-Coded OFDM-IM Systems

A powerful PTS strategy boosted by a novel discrete crow search algorithm for reducing the PAPR of UFMC signals

Abstract As being one of the main waveform candidates developed for meeting the demands of fifth generation (5G) and beyond telecommunication technologies, universal filtered multicarrier (UFMC) has various appealing features contributing to overcome many obstacles in wireless communication. However, due to the usage of multiple subcarriers, UFMC signals suffer from having high peak-to-average power ratio (PAPR), which has to be kept at low level to prevent the communication quality from being deteriorated. To overcome the problem of high PAPR in the UFMC signals, an advanced version of partial transmit sequence (PTS) was created for PAPR alleviation by integrating an intelligent optimization algorithm in place of its random phase generator. To this end, crow search algorithm (CSA) was utilized. Initially, its novel discrete version called DCSA was developed to make it suitable to be employed in phase sequence optimization, which is a type of combinatorial optimization problem to be solved in discrete space. After the integration of DCSA into the conventional PTS, an advanced PTS variant named DCSA-PTS was created for the UFMC. Optimizing the phase sequences via the DCSA instead of generating them in a random way enhances the performance of PTS scheme. Thanks to the DCSA-based phase optimization, it becomes possible to attain better phase combinations in smaller number of searches. The advantage of using DCSA as a phase optimizer is supported by the simulation results. Due to the superior phase optimization performance of our novel DCSA, the proposed DCSA-PTS strategy clearly outperforms the other schemes considered in this paper.

Optimized intensity-modulated type PTS-based PAPR reduction scheme for intensity-modulated direct-detection optical OFDM systems.

High peak-to-average power ratio (PAPR) of the signal is a major drawback in optical orthogonal frequency division multiplexing (OFDM) system. In this paper, an intensity-modulated type Partial Transmit Sequences (PTS) based scheme is proposed and applied to the intensity-modulated OFDM (IMDD-OFDM) system. The proposed intensity-modulated type PTS (IM-PTS) scheme ensures that the time-domain signal output by the algorithm is real value. What's more, the complexity of the IM-PTS scheme has been reduced without much performance penalty. A simulation is performed to compare the PAPR of different signal. In the simulation, the PAPR of OFDM signal is reduced from 14.5 dB to 9.4 dB at 10-4 probability. We also compare the simulation results with another algorithm based on the PTS principle. A transmission experiment is conducted in a seven-core fiber IMDD-OFDM system at a rate of 100.8Gbit/s. The Error Vector Magnitude (EVM) of received signal is reduced from 9 to 8 at -9.4dBm received optical power. Furthermore, the experiment result shows that the reduction of complexity has little performance impact. The optimized intensity-modulated type PTS (O-IM-PTS) scheme effectively increases the tolerance of the nonlinear effect of the optical fiber and reduces the requirement for linear operating range of optical device in the transmission system. During the upgrade process of the access network, there is no need to replace the optical device in the communication system. What's more, the complexity of PTS algorithm has been reduced, which lower data processing performance requirements of the devices such as ONU and OLT. As a result, the cost of network upgrades is reduced a lot.

PAPR Reduction in OFDM System Using Metaheuristic Algorithm

The advancement of technology necessitates the development of more sophisticated modulation strategies for wideband digital communication systems. The requirements for high-speed data transmissions can be effectively met by utilizing orthogonal frequency division multiplexing, which is an effective technique. However, a high peak-to-average power ratio (PAPR) is one of the key limits that OFDM systems face, both in terms of their performance and their power efficiency. The evaluation of the PAPR reduction has become a topic of widespread interest in this present decade due to the relevance it holds in the industrial and scientific communities. The purpose of this study is to show the combination of the bat algorithm with the partial transmit sequence scheme as an effective way for reducing PAPR that also eases the burden of computing work. For the purpose of providing a comparative evaluation of the PAPR reduction performance, a number of simulations using various partial transmit sequence schemes have been carried out. The findings of the simulation show that the BA-PTS scheme has the potential to provide superior PAPR reduction performance while simultaneously reducing the computational load.

A LOW-COMPLEXITY PTS TECHNIQUE–BASED IMPROVED PSO ALGORITHM FOR PAPR REDUCTION IN OFDM SYSTEMS

Partial transmit sequence (PTS) is a potent and distortionless scheme frequently used to lower the high peak-to-average power ratio (PAPR) levels in orthogonal frequency division multiplexing (OFDM) signaling. Although this method effectively reduces the PAPR, its main limitation is the exponential growth in the computational expense caused by the exhaustive search for the optimal complex of rotation factors. This work proposes a suboptimal PTS scheme based on an improved particle swarm optimization (PSO) algorithm. The latter exploits heuristics to find the best-matched weighting factors complex in fewer computations. A comparison against existing techniques ascertains the superior efficiency of the proposed scheme in terms of PAPR mitigation and computational burden.

VHDL implementation of circular shifting‐partial transmit sequence in MIMO OFDM systems

SummaryOne of the basic issues in orthogonal frequency‐division multiplexing (OFDM) frameworks is the peak‐to‐average power ratio (PAPR). There are several PAPR reduction methods available. The partial transmit sequence (PTS) technique is considered one of the superior techniques for overcoming this issue. In this study, an efficient VHSIC hardware description language VHDL implementation of the PTS design utilising roundabout circular shifting CS was planned. The proposed structured method was designed as a real‐time prototype circuit over a field programmable gate array (FPGA) utilising the VHDL language. The implementation results of the prototype circuit in terms of the resources used in the FPGA using the Xilinx synthesis tool on the Virtex‐5 board for SISO, 2 × 2 MIMO and 4 × 4 MIMO models for N‐IFFT 64 and 256 points are presented. The structured framework effectively combined to be a compact framework with low intricacy and high speed. Testing of the implemented circuit verified its functionality. A comparison of our proposed CS‐PTS scheme with previously used PTS schemes, such as the subblock scheme, showed that our proposed method is superior in terms of hardware complexity reduction.

Continuous-unconstrained and global optimization for PSO-PTS based PAPR reduction of OFDM signals

Orthogonal frequency division multiplexing (OFDM) is a superior technology for the high-speed data rate of wire-line and wireless communication systems. However, one of the major drawbacks of OFDM signals is the high peak-to-average power ratio (PAPR) problem inherent in 5G waveform design. High PAPR causes OFDM signal distortion in the nonlinear region of the high power amplifier (HPA), and signal distortion leads to a decrease in bit error rate (BER). Partial transmit sequence (PTS) technique is a very attractive technique for PAPR reduction. However, to match the optimum condition on PTS for PAPR reduction, the computational unpredictability and cost of traditional PTS strategy are enormous, thus it is urgent to enhance computational efficiency to obtain the optimal PTS. In this paper, an improved scheme called Continuous-Unconstrained Particle Swarm Optimization based PTS (CUPSO-PTS) technique for optimum phase rotation factors searching is presented. A class of continuous-phase PTS schemes has been proposed to obtain the global optimal phase factor, and the theoretical boundaries can be determined in the continuous-unconstrained searching space. Conversely, when the phase factor values in continuous-unconstrained domain, the equivalent unconstrained PTS optimization can drastically accelerate convergence and reduce total calculation cost. In this paper, we compare the performance of Binary PSO based PTS (BPSO-PTS) scheme and Elitist Genetic Algorithm based PTS (EGA-PTS) scheme for 16-QAM modulation scheme. Theoretical analysis and simulations show that the proposed CUPSO-PTS scheme could provide a significant PAPR reduction in the OFDM system, which outperforms the OFDM systems with the traditional PTS scheme by 0.55 dB at CCDF of 10−3 in PAPR reduction. And 84.74% computational complexity is saved.

Precoded SLM and PTS Scheme for Reduced PAPR in OFDM for Wireless Communications

Orthogonal Frequency Division Multiplexing (OFDM) contribute high data rates in current as well as future wireless communication systems but it aches from high Peak to Average Power Ratio (PAPR). But this high PAPR makes the High-Power Amplifier (HPA) complex which increases the cost of it and leads to the drawbacks like Inter Carrier Interference (ICI) and rise in out of band radiation. Even though many techniques are there to decrease the complexity of HPA by reducing the PAPR, Selected Mapping (SLM) and the Partial Transmit Sequence (PTS) provides less PAPR with low complexity. In this paper, both PTS and SLM are combined with Discrete Sine Transform (DST) and their PAPR and efficiencies are also compared with OFDM signal. The proposed hybrid DST-PTS and DST-SLM provides less PAPR compared to OFDM, SLM and PTS techniques with low complexity. Also, the bit error rate for DST-SLM and DST-PTS techniques are compared for different values of SNR. In future wireless communication systems, these proposed techniques can be used as they provide less bit error rate and less PAPR with low complexity

Retracted: Peak to average power ratio reduction of ZT DFT‐S‐OFDM signals using hybrid improved monarch butterfly optimization‐PTS scheme with TR‐clipping scheme

SummaryCurrent research on zero‐tail discrete Fourier transform spread OFDM, an add on to conventional discrete Fourier transform DFT‐OFDM modulation without cyclic prefix (CP). Its low power tail is configured for coping up with channel's delay spread. Advantageous feature of ZT DFT‐S‐OFDM has drawn researchers for deploying it as a potential waveform candidate to fifth generation (5G). However, the intrinsic shortcoming of high peak to average power ratio (PAPR) should be alleviated. In order to improve that work, we propose a hybrid PAPR scheme that implements optimized partial transmit sequence (PTS) with tone reservation (TR) with clipping technique. Its earlier work stresses for reducing PTS scheme's computational complexity with enhanced version of monarch butterfly optimization (MBO) for PAPR reduction in ZT DFT‐S‐OFDM system. The proposed model reduced the correlation among the candidate signals. In this paper, we further reduce PAPR by deploying TR clipping pair, which reduces the influence of clipping noise and decreases ZT DFT‐S‐OFDM signal's PAPR at same time. The proposed hybrid technique produces excellent PAPR reduction while improving receiver sensitivity and effective throughout. The performance comparison is done using the parameters like PAPR and BER to confirm that this introduced design exceeds current waveforms designs with more economical design structure.

A novel discrete elephant herding optimization-based PTS scheme to reduce the PAPR of universal filtered multicarrier signal

The recently proposed waveform called universal filtered multicarrier (UFMC) has already managed to get the attention of science world due to its superior features and it has been accepted as one of the foremost fifth generation (5G) waveform contenders. However, due to being a type of multicarrier waveform, the UFMC suffers from the problem of high peak-to-average power ratio (PAPR). In this paper, a new discrete elephant herding optimization-based partial transmit sequence (DEHO-PTS) scheme is suggested to reduce the PAPR of UFMC signals to minimum levels. Due to the fact that the optimization of phase rotation factors multiplied by the sub-blocks in the conventional partial transmit sequence (PTS) technique is a combinatorial optimization problem to be solved in discrete space, in order to integrate the elephant herding optimization (EHO) algorithm into the PTS scheme, we developed its discrete version (DEHO) in this paper. In the simulations, the capability of the suggested DEHO-PTS procedure to minimize the PAPR, suppress the out-of-band emission and decrease the bit error rate of the UFMC signal amplified via a nonlinear high power amplifier was analyzed. Simulation results clearly indicate that our proposed DEHO-PTS procedure can be a serious option for UFMC waveform to minimize the PAPR values of transmission signals due to its significant PAPR reduction, side lobe suppression and bit error rate performances with low computational complexity.

Reducing Complexity in PTS Scheme using Optimization Techniques to reduce PAPR in OFDM Systems

OFDM is a technique used to combat Inter Symbol Interference (ISI) in wireless communication systems. OFDM offers high reliable data rate over frequency selective channels. But the drawback is high Peak to Average Power Ratio (PAPR) which will affect the power amplifier in the RF front end. Partial Transmit Sequence (PTS) has proven to be the efficient technique to minimize the PAPR in OFDM systems and it does not affect the Bit Error Rate (BER) much. But PTS in turn suffers from high search complexity. The optimization algorithms can offer a tradeoff between the search complexity and PAPR reduction. In this work the phase factor optimization in PTS scheme is converted into a one dimensional optimization problem. Genetic Algorithm (GA), Simulated Annealing (SA) and Particle Swarm Optimization (PSO) are applied to the problem defined. They are also compared in terms of PAPR reduction and complexity. The fitness functions are chosen according to the optimization technique.

Advanced switching DE algorithm based PTS companding technique for PAPR reduction in OFDM systems

Partial Transmit Sequence (PTS) is an efficient method for diminishing the high Peak to Average Power Ratio (PAPR) for Orthogonal Frequency Division Multiplexing (OFDM) system. However, finding an optimum phase factor among different combinations of phase factors, rigorous searching is required. It ultimately increases the computational complexity. For practical implementation high computational complexity becomes crucial problem when a huge number of subcarriers are used in PTS based PAPR reduction technique for OFDM system. Hence, to reduce computational load an Advanced Switching Differential Evolution (ASDE) algorithm is incorporated in PTS scheme. In the proposed approach an optimized switching DE algorithm enhances computational efficiency. But, the PAPR reduction performance becomes poorer compared to conventional PTS scheme. To further reduce PAPR, two thresholds based $$\mu $$ law companding technique is incorporated along with ASDE PTS for OFDM system. The Matlab simulation revealed that, the proposed scheme performed better PAPR reduction and Bit Error Rate performance with less complexity compared to other relevant techniques.

Polygon Number Algorithm for Peak‐to‐Average Ratio Reduction of Massive 5G Systems Using Modified Partial Transmit Sequence Scheme

The high peak‐to‐average power ratio (PAPR) of the transmit signal is a major shortcoming of OFDM systems, which results in band radiation and distortion due to the nonlinearity of the high‐power amplifier (H.P). To resolve the traditional OFDM high‐PAPR issue, where the transmit sequence is designed to avoid similar data from being sent in the same order to reduce PAPR, there are numerous conventional ways for lowering the PAPR for OFDM system, such as selective mapping, tone reservation, block coding, filtering, clipping, and partial transmit sequence (PTS). This study proposes a new method called polygon number algorithm (PN) with conventional partial transmit sequence (C‐PTS). This method (PN‐PTS) processes the entered data before sending it, taking advantage of the number nonsimilarity according to the geometry of the number to prevent direct sending of similar data via PTS, and thus, this improved the level of PAPR rise in the proposed system. The amount of reduction that can be achieved in PAPR is up to 8 dB by different techniques. The best result obtained was the amount of reduction between the conventional method and the proposed method is 4.5683 where N = 64. Besides this, there is no transmission of side information (SI), which improves transmission efficiency. Finally, this method is easy in the calculation process and the ciphering and deciphering of data, which adds a few calculations.

A low complexity partial transmit sequence approach based on hybrid segmentation scheme

The partial transmit sequences (PTS) is regarded as a promising scheme for inhibiting ‎the high peak-to-average power ratio (PAPR) problem in the orthogonal frequency division ‎multiplexing (OFDM) systems. The PTS scheme relies on partitioning the ‎data sequence into subsets and weighting these subsets by a group of the phase rotation ‎factors. Although the PTS can efficiently reduce the high PAPR value, a great ‎computational complexity (CC) level restricts the utilization of the PTS scheme in practical ‎applications. In PTS, there are three common types of segmentation schemes; ‎interleaving (IL-PTS), pseudo-random (PR-PTS), and adjacent (Ad-PTS) schemes. This ‎paper presents a new algorithm named hybrid pseudo-random and interleaving cosine wave shape ‎‎(H-PRC-PTS) by combining the PR-PTS scheme and the symmetrical ‎interleaving cosine wave shape (S-IL-C-PTS) scheme which was proposed in our previous ‎work. The results indicate that the suggested algorithms can ‎diminish the PAPR value like the PR-PTS scheme, whereas the CC level is reduced significantly.

A REVIEW OF NOVEL APPROACH FOR REDUCTION IN SUB CARRIER PEAK TO AVERAGE POWER RATIO IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING

In last few decades the demand for multimedia data services has grown up fastly. One of the most promising multicarrier system, Orthogonal Frequency Division Multiplexing (OFDM) allow large number of capacity the number of subcarriers, high data rates and ubiquitous coverage with high mobility. But OFDM is extensively affected by peak to average power ratio (PAPR). Unfortunately, the high PAPR inherent to OFDM signal envelopes will frequently drive high power amplifiers (HPAs) which are operate in the nonlinear region. The nonlinearity of the High Power Amplifier exhibits phase and amplitude distortions, which causes loss of orthogonality between the subcarriers; also (ICI) is introduced in the source signal. This dissertation is basically focused on PAPR reduction in OFDM system and measuring BER in different Modulation Technique. In PAPR reduction Signal companding methods have low complication, high distortion and spectral properties; however, we have limited PAPR reduction capabilities. Partial transmit sequences (PTS) and selected mapping (SLM), have also been considered for PAPR reduction. Such kind of techniques are very efficient and distortion less, Also the SLM is very good technique to the PAPR problem in single carrier system. This method has low complexity as well as it is data independent. 
 In this paper, we are describing a combine technique of SLM and PTS to minimize the PAPR. In PTS scheme, number of sub blocks increases; the IFFT block to be performed for sub blocks also increases. Simulation results have shown that the reductions of PAPR of proposed scheme is more than PTS and SLM methods as well as the difficulty reduced considerably.

RETRACTED ARTICLE: Peak to average power ratio reduction of ZT DFT-s-OFDM signals using improved monarch butterfly optimization-PTS scheme

For traditional orthogonal multiplexing frequency division (OFDM) systems, a novel Zero Tail Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing Division (ZT DFT-s-OFDM) waveform architecture has recently been proposed as a problem solution of low peak to average power ratio (PAPR) efficiency. The ZT DFT-s-OFDM system allows the delay in the transmission of the channel with multipath to be dynamically copied, thus the limitations to be rectified with the hard-coded Cyclic Prefix (CP). However it is affected by few roadblocks during the transmission of data, and the primary one involves the high peak-to-average power ratio (PAPR), which results in saturation observed in the power amplifier, production of more amount of interference and decreased resolution in elements such as digital/analog converters, which were considered as nonlinear. Partial transmit sequences (PTSs) is a promising plan and direct technique, ready to accomplish a viable PAPR decrease execution, yet it requires a thorough hunt to locate the ideal stage factors, which causes high computational multifaceted nature expanded with the quantity of sub-blocks. Right now, the author proposed a reduced computational complexity PTS scheme, in view of a new swarm knowledge algorithm, which is termed as Improved Monarch Butterfly Optimization (IMBO) for PAPR decrease with the ZT DFT-s-OFDM framework. The IMBO is a new swarm intelligence algorithm, with the capability of achieving an efficient optimization search that implements phase weighting process with less complexity for selecting optimum phase factors. Also, the proposed technique is quite efficient in looking for a fusion with optimal character of phase rotation factors for minimizng the computational difficulty involved. The outcomes of simulation indicate that IMBO-based PTS algorithm can substantially reduce PAPR employing an easy network structure in comparison with classical algorithms such as PTS scheme for conventional OFDM and PTS with ZT-DFT-s-OFDM.

Genetic Algorithm Based Bilayer PTS Scheme for Peak-to-Average Power Ratio Reduction of FBMC/OQAM Signal

Partial transmit sequence (PTS) scheme has been well applied to reduce the high peak-to-average power ratio (PAPR) of the orthogonal frequency division multiplexing (OFDM) signal. However, due to the signal structure differences between the filter bank multicarrier and offset quadrature amplitude modulation (FBMC/OQAM) signal and the OFDM signal, the conventional PTS scheme is not applicable to the FBMC/OQAM signal. Considering the PAPR reduction issue for the FBMC/OQAM signal, this paper proposes a genetic algorithm (GA) based bilayer partial transmit sequence (GA-BPTS) scheme. In order to reduce the computational complexity, the proposed scheme continues to partition each subblock, transforming the single layer structure of the conventional PTS into a bilayer phase factor search structure, and introduces a penalty threshold. Then the suboptimal phase factor vector is obtained by using the GA. Meanwhile, before PAPR reduction processing, aided by the proposed prototype filter which has the better performance of out-of-band attenuation than the PHYDAYS filter, the GA-BPTS scheme can effectively reduce the PAPR of the FBMC/OQAM signal. The simulations have confirmed that the proposed scheme not only provides an excellent PAPR performance but also decreases the computational complexity compared with the conventional PTS scheme.

PTS scheme based on MCAKM for peak‐to‐average power ratio reduction in OFDM systems

This study considers the application of the partial transmit sequence (PTS) technique to reduce the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. The conventional PTS approach has proved its high effectiveness in PAPR reduction for OFDM signals where the reduction performance of PAPR depends mainly on phase rotation factors. Finding the optimal phase rotation factors requires an exhaustive computationally task, which is a serious implementation problem in practical systems. To fix this issue of computational complexity and reduce the PAPR at the same time, in the present work, a novel PTS approach based on multi-population cultural algorithm adopting knowledge migration (MCAKM) has been proposed for optimal phase rotation factors search. Computer simulation results show that the proposed MCAKM–PTS technique leads to a better PAPR reduction and bit error rate performance with a significant reduction in computational complexity compared to the conventional PTS and the previously optimisation algorithms applied to PTS such as particle swarm optimisation, artificial bee colony, and electromagnetism-like algorithm.

PAPR reduction performance of bat algorithm in OFDM systems

The progression in technology requires improved modulation techniques for wideband digital communication systems. Orthogonal frequency division multiplexing is efficacious systems to fulfill high-speed data transmissions needs. However, high peak-to-average power ratio (PAPR) is one of the significant limitations on the performance and power efficiency of OFDM systems. Due to industrial and scientific relevance, the assessment of the PAPR reduction has become popular subject in the current decade. This study presents the combination of bat algorithm with partial transmit sequence scheme as an efficient PAPR reduction method with an alleviated computational load. A set of simulations with different partial transmit sequence schemes are performed to comparatively evaluate the PAPR reduction performance of the partial transmit sequence based on bat algorithm scheme in OFDM system. The simulation results elucidate that BA-PTS scheme can provides better PAPR reduction performance with less computational load.