Power Ratio Reduction Research Articles

Papr reduction of FBMC-OQAM signals using Phase Search-PTS and modified discrete fourier transform spreading

In this research, a novel peak-to-average power ratio (PAPR) reduction technique for filter bank multicarrier (FBMC) modulation systems is presented. With multicarrier systems like FBMC, the strategy focuses on the survival of the fittest principle to suit the value of PAPR. The Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation (FBMC-OQAM) has recently captured the attention of numerous academics due to its minimal adjacent channel leakage ratio (CLR). Unfortunately, the issue of increased PAPR measurement has a negative impact on the effectiveness of the FBMC system's energy measurement. In this study, the Phase search-based Partial Transmit Sequence (PS-PTS) approach and Modified Discrete Fourier Transform Spreading (MDFT) are developed for the PAPR reduction of the FBMC-OQAM signals. The increased PAPR measurement is reduced using the PTS and MDFT with osprey optimization method, which may result in a PAPR reduction of roughly 5.1 dB as comparable to the conventional approach.

PAPR Suppression for Angular-Domain-Based Massive Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing System

In this paper, the precoding-based peak-to-average power ratio (PAPR) reduction methods are studied for the massive multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system in the angular domain. The expectation maximization generalized approximate message passing algorithm and the proposed optimized alternating direction method of multipliers (OADMM) scheme are adopted here to explore the system characteristics in terms of the symbol error ratio (SER) performance, the PAPR reduction efficiency, and the inter user interference (IUI). Specifically, the high PAPR problem is reduced to no more than 0.18 dB by using the inherent property of the massive MIMO-OFDM angle division multiple access (ADMA) system with relatively reduced computational complexity. Moreover, the value of SER is around 10−5 dB when the proposed technique is performed. Computer numerical simulation results verify the efficiency of the proposed technique from the perspective of SER, PAPR suppression, and IUI.

An Optimized Algorithm for Peak to Average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing Communication Systems: An Integrated Approach

An Optimized Algorithm for Peak to Average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing Communication Systems: An Integrated Approach

PAPR Reduction in Cyclic Prefix OFDM (5G) System using Group Codeword Shifting Technique

Cyclic Prefix Orthogonal Frequency Division Multiplexing (CPOFDM) is a 5G multicarrier waveform that enables high data rates and spectrum efficiency improvements. The primary drawback of CPOFDM is that it has a high peak to average power ratio (PAPR), which is a characteristic of all multicarrier modulation techniques. We study the application of a Group Codeword Shift (GCS) approach to reduce the peak to average power ratio (PAPR) in a CPOFDM system in this article. Additionally, we compared the results of peak to average power ratio (PAPR) reduction with low complexity in CPOFDM using a Group Codeword Shift (GCS) approach, Selective Codeword Shift (SCS), Median Codeword and Conventional CPOFDM.

Optimized intelligent framework for peak-to-average power ratio reduction in filter bank multicarrier

Optimized intelligent framework for peak-to-average power ratio reduction in filter bank multicarrier

FPGA implementation of a sub-400ns 6G free-space optical wireless communications transmitter.

Future wireless networks are planned to service many applications with an Ultra Low-Latency (ULL) requirement. Numerous 6G systems have been proposed including more traditional electro-magnetic (EM) antenna transmissions and optical wireless communications (OWC). For extremely wide-band operation, the traditional approaches require digital pre-distortion and other processing techniques which, in turn, require more computational resources and processing times thus increasing latency. Alternatively, OWC has the potential for extremely wide bandwidths in 6G without the need for as much digital signal processing. In order to realise ULL performance, a minimum number of digital signal processing (DSP) blocks is required, as well as an optimal design of each of these. In this letter, we propose a DSP solution for ULL and peak to average power ratio (PAPR) reduction for OWC systems. Unitary checkerboard precoding - orthogonal frequency division multiplexing (UCP-OFDM) is chosen as the modulation scheme and has been implemented within a single digital block avoiding the use of standard OFDM which would otherwise require multiple digital blocks. Experimentally validated results successfully demonstrate a 2.21184 GSps wireless link at distances of up to 2m in noisy daylight settings. Bit error rates (BER) of 0 at root mean square (RMS) error vector magnitude (EVM) of 4.09% are achieved. A complete digital line-up of an OWC transmitter chain for this work contains only three core blocks and ULL of less than 400 ns.

Peak to average power ratio reduction techniques based on chirp selection for single and multi‐user orthogonal chirp division multiplexing system

AbstractThis article deals with peak to average power (PAPR) reduction in a single and multi‐user orthogonal chirp division multiplexing (OCDM) context. Two methods for PAPR reduction based on the selection of the frequency variation (up or down) of the chirps are first presented in a single user system. The first technique consists in considering two OCDM signals generated with up and down chirps, respectively, and selecting the one offering lowest PAPR. The second PAPR reduction method is based on usual clipping, and in that case the chirp selection aims to reduce the clipping noise. An adapted receiver is presented, based on the maximum likelihood estimation of the frequency variation (up or down) of the chirp. Then, a general procedure for multi‐user OCDM transmission is introduced, where a sub‐band of the available bandwidth is dedicated to each user, whose frequency of the chirps varies within this sub‐band. Next, the PAPR reduction techniques are generalised to this multi‐user OCDM system. Moreover, a performance analysis of the first PAPR reduction method is developed, and it is shown through simulations that theoretical and numerical results match for both Nyquist rate and oversampled signals. It is also shown that the chirp selection reduces the clipping noise, and improves the bit error rate performance compared with clipping only.

Peak to average power ratio reduction in spectrally efficient FDM using repeated clipping and filtering

Multi-carrier transmission may be considered one of the important developments in wireless communications. Spectrally efficient frequency division multiplexing (SEFDM) is a promising multi-carrier modulation which can significantly improve utilization of spectral. The SEFDM has high peak to average power ratio (PAPR) like any multicarrier system. High PAPR reduces the random forest (RF) transmitter power amplifier efficiency, which minimize the use of this technique in limited power supply transmitters. In this work, a repeated clipping and filtering method is introduced to reduce the PAPR in SEFDM with minimum or no out of band radiation. The results of the simulated approach show that the PAPR of the SEFDM was reduced from 16.264 dB to 7.9146 dB with marginal degradation in system performance when the clipping ratio varied from 4 to 2.

Зменшення відношення пікової до середньої потужності за допомогою алгоритму компандування для NOMA сигналу

Майбутні системи бездротового зв’язку можуть підтримувати величезну кількість з’єднань і підвищити ефективність використання спектра завдяки використанню підходу неортогонального множинного доступу NOMA (non-orthogonal multiple access). Однак високі рівні відношення пікової до середньої потужності PAPR (Peak-to-Average Power Ratio) можуть негативно впливати на NOMA, що призводить до зниження продуктивності системи та ускладнення підсилювачів потужності. У цьому дослідженні пропонується зменшити PAPR в NOMA, використовуючи методи компандування для 512, 256 і 64 піднесучих з метою вирішення цієї проблеми. Висока пікова потужність сигналів NOMA може бути ефективно стиснута за допомогою нелінійних методів компандування, таких як ущільнення за μ-законом і A-законом, що зменшує спотворення і покращує загальну надійність системи. Для оцінки ефективності запропонованих методів компандування використано моделювання, результати якого свідчать про значне зменшення PAPR, що забезпечує підвищення ефективності коефіцієнта бітових помилок BER (Bit Error Rate) та стійкості передачі в системах зв’язку на основі NOMA. Запропонований метод порівнюється з традиційними A-законом (C-A-law) та μ-законом (C-μ-law).

Machine Learning Based Tuner for Frequency-Selective PAPR Reduction

Frequency-selective peak-to-average power ratio (PAPR) reduction is essential in networks such as 5 G New Radio (NR) that support frequency-domain multiplexing of users and services. However, stemming from the frequency-selective shaping of the involved clipping noise, the relation between the intended PAPR target and the actually realized PAPR is known to be heavily nonlinear, which complicates the PAPR reduction. In this article, a novel machine learning (ML)-based solution, called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PAPRer</i> , is proposed to automatically and accurately tune the optimal PAPR target for frequency-selective PAPR reduction. This is achieved by utilizing the features related to the used clipping noise filter and minimization of the defined loss function, through supervised learning, which quantifies the PAPR target estimation accuracy. An analytical clipping noise power-based method is also devised for reference purposes. Extensive numerical evaluations in 5 G NR context are provided and analyzed, showing that PAPRer can very accurately predict and tune the optimal PAPR target. These results, together with the provided complexity assessment, demonstrate that the proposed PAPRer offers a favorable performance-complexity tradeoff in choosing the optimal PAPR target for frequency-selective PAPR reduction.

Peak to Average Power Ratio Reduction Using Companding Algorithm for NOMA Waveform

Peak to Average Power Ratio Reduction Using Companding Algorithm for NOMA Waveform

Orthogonal variable spreading factor encoded unmanned aerial vehicle‐assisted nonorthogonal multiple access system with hybrid physical layer security

AbstractPhysical layer security (PLS) can improve the security of both terrestrial and nonterrestrial wireless communication networks. This study proposes a simplified framework for nonterrestrial cyclic prefixed orthogonal variable spreading factor (OVSF)‐encoded multiple‐input and multiple‐output nonorthogonal multiple access (NOMA) systems to ensure complete network security. Various useful methods are implemented, where both improved sine map and multiple parameter‐weighted‐type fractional Fourier transform encryption schemes are combined to investigate the effects of hybrid PLS. In addition, OVSF coding with power domain NOMA for multi‐user interference reduction and peak‐to‐average power ratio (PAPR) reduction is introduced. The performance of ‐rated convolutional, turbo, and repeat and accumulate channel coding with regularized zero‐forcing signal detection for forward error correction and improved bit error rate (BER) are also investigated. Simulation results ratify the pertinence of the proposed system in terms of PLS and BER performance improvement with reasonable PAPR.

Long Short-Term Memory Neural Network assisted Peak to Average Power Ratio Reduction for Underwater Acoustic Orthogonal Frequency Division Multiplexing Communication

Long Short-Term Memory Neural Network assisted Peak to Average Power Ratio Reduction for Underwater Acoustic Orthogonal Frequency Division Multiplexing Communication

A Modified Selective Mapping Technique for Peak-to-Average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing with Index Modulation Systems

In this study, we propose a modified selective mapping (SLM) technique to reduce the Peak-to-Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing with Index Modulation (OFDM-IM) systems. The main reason for using Reed–Muller and Polar codes is to protect the information bits to be transmitted while providing error correction capability and improved PAPR performance to the transmitted signal. Although OFDM-IM technology is a popular communication transmission technology recently, one of its disadvantages is that the transmitted signal has a high PAPR. The proposed method uses the Hamming weight distribution of the specific order Reed–Muller code to create a corresponding lookup table to select the subcarriers that are active in the OFDM-IM system. Moreover, it can correct errors in the information used. The proposed method also uses Polar codes as a channel encoder of the OFDM-IM system to analyze its performance in improving the PAPR. The simulation results show that method can not only improve the PAPR performance of OFDM-IM systems but also provide OFDM-IM transmission-signal error correction capacity.

LADMM-Based PAPR-Aware Precoding for Massive MIMO-OFDM Downlink Systems

We tackle the peak to average power ratio (PAPR) reduction of an orthogonal frequency division multiplexing (OFDM)-based massive multi-user (MU) multiple-input multiple-output (MIMO) downlink systems in this paper. Utilizing the redundant degree of freedom (DOF) provided by a large number of antennas equipped at the base station, we first formulate OFDM modulation, MU precoding, and PAPR reduction into a non-convex optimization problem. By using the linearized alternating direction method of multipliers (LADMM), we directly address the non-convex PAPR-aware precoding problem without any relaxation in terms of PAPR and multi-user interference (MUI), which is completely different from the existing convex optimization methods based on relaxations. At the same time, the paper is also the first work to directly solve the non-convex PAPR-aware precoding optimization. The experimental results demonstrate that the LADMM method gets the comparable PAPR reduction and symbol error rate (SER), faster convergence, and lower complexity than the existing relaxed methods.

Improved Peak-To-Average Power Ratio (Papr) Reduction With Optimized Side Information Using MIMO-OFDM

Improved Peak-To-Average Power Ratio (Papr) Reduction With Optimized Side Information Using MIMO-OFDM

Linear precoder design for peak‐to‐average power ratio reduction of generalized frequency division multiplexing signal using gradient descent methods

AbstractThis article addresses linear precoder design for the peak‐to‐average power ratio (PAPR) reduction of the generalized frequency division multiplexing (GFDM) scheme. This design relies on minimizing various statistical parameters of the instantaneous power of the GFDM signal—including variance, second and third moments—using gradient‐based optimization methods. In this regard, a general framework of four different scenarios, which employs the steepest descent and conjugate‐gradient methods and utilizes two different approaches of fixed and dynamic step‐sizing, is proposed. In the case of fixed step‐sizing, the results demonstrate that the algorithm diverges in some scenarios and provides low‐speed convergence for the others due to its inability in meeting the terminating threshold regarding minimizing objective function to a desirable level. However, dynamic step‐sizing using the Wolf line search rule circumvents these drawbacks, outperforms the existing research, and converges in all scenarios to a precoder providing advantages in terms of design speed and achievable PAPR, while keeping the symbol error rate and out‐of‐band emissions at the ranges of the un‐precoded GFDM systems. Moreover, the results confirm the comprehensiveness of the proposed framework in adapting to various GFDM statistical parameters and gradient methods.

An efficient reconfigurable peak cancellation model for peak to average power ratio reduction in orthogonal frequency division multiplexing communication system

&lt;span lang="EN-US"&gt;The peak to average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) communication system will be reduced using reconfigurable peak cancellation (RPC). RPC will also aid in improves the error vector magnitude (EVM) and reduces adjacent channel leakage ratio (ACLR) in OFDM communication system. The proposed RPC design methodology and practical implementation using field programmable gate array (FPGA) are discussed. The proposed RPC has been demonstrated using VIRTEX-7 XC7Z100 dual-core FPGA device with less hardware difficulty and minimum utilization of FPGA resources. The proposed RPC improves the efficiency of OFDM communication process by reducing complementary cumulative distribution function (CCDF) with respect to instantaneous power in dB. A comparison analysis was done between the existing selective mapping (SLM) method with proposed RPS method with respect FPGA resource utilization. The proposed RPC is implemented using VIRTEX-7 XC7Z100 dual-core FPGA device. Its effectively utilizing sub-carriers, fast Fourier transform (FFT) filter, bandwidth, and sampling frequency. Due to parallel switching operation, it reduces the PAPR, ACLR and improves EVM in OFDM signal with less hardware complexity.&lt;/span&gt;

A Joint Design of SCMA Codebook and PTS-Based PAPR Reduction for Downlink OFDM Scheme

In this paper, a joint design of sparse code multiple access (SCMA) codebook and peak-to-average power ratio (PAPR) reduction based on the partial transmit sequence (PTS) technique is proposed for the downlink orthogonal frequency division multiplexing (OFDM) scheme. A benchmark scheme is firstly devised based on a direct extension of the conventional PTS-based OFDM scheme. Based on the characteristics of the near-optimal SCMA codebook designs reported in our previous work, a PTS-based SCMA-OFDM design is proposed by carefully determining the rotation angles of the SCMA codebooks, according to the adopted signal sub-constellations. A receiver which does not need the side information is further devised. Considering the phase ambiguity issue of the receiver, the PTS angles have been carefully refined. When compared to both the original scheme that does not consider PAPR reduction techniques and the benchmark scheme, the proposed scheme achieves a significantly enhanced PAPR performance with approximately the same error performance. In addition, a comparable PAPR performance, an improved error performance, and a lower computational complexity can be achieved when compared to the clipping-based SCMA-OFDM scheme reported in the previous literature.

EVM Mitigation With PAPR and ACLR Constraints in Large-Scale MIMO-OFDM Using TOP-ADMM

Although signal distortion-based peak-to-average power ratio (PAPR) reduction is a feasible candidate for orthogonal frequency division multiplexing (OFDM) to meet standard/regulatory requirements, the error vector magnitude (EVM) stemming from the PAPR reduction has a deleterious impact on the performance of high data-rate achieving multiple-input multiple-output (MIMO) systems. Moreover, these systems must constrain the adjacent channel leakage ratio (ACLR) to comply with regulatory requirements. Several recent works have investigated the mitigation of the EVM seen at the receivers by capitalizing on the excess spatial dimensions inherent in the large-scale MIMO that assume the availability of perfect channel state information (CSI) with spatially uncorrelated wireless channels. Unfortunately, practical systems operate with erroneous CSI and spatially correlated channels. Additionally, most standards support user-specific/CSI-aware beamformed and cell-specific/non-CSI-aware broadcasting channels. Hence, we formulate a robust EVM mitigation problem under channel uncertainty with nonconvex PAPR and ACLR constraints catering to beamforming/broadcasting. To solve this formidable problem, we develop an efficient scheme using our recently proposed three-operator alternating direction method of multipliers (TOP-ADMM) algorithm and benchmark it against two three-operator algorithms previously presented for machine learning purposes. Numerical results show the efficacy of the proposed algorithm under imperfect CSI and spatially correlated channels.