Performance Investigation of Peak Shrinking and Interpolating the PAPR Reduction Technique for LTE-Advance and 5G Signals

Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform generation in wideband digital communication since its first appearance in digital audio broadcasting (DAB) in Europe in 1980s, and it is indeed in use. As has been seen, the OFDM based waveforms work well with time division duplex operation in new radio (NR) systems in 5G systems, supporting delay-sensitive applications, high spectral efficiency, massive multiple input multiple output (MIMO) compatibility, and ever-larger bandwidth signals, which has demonstrated successful commercial implementation for 5G downlinks and uplinks up to 256-QAM modulation schemes. However, the OFDM waveforms suffer from high peak to average power ratio (PAPR), which is not desired by system designers as they want RF power amplifiers (PAs) to operate with high efficiency. Although NR offers some options for maintaining the efficiency and spectral demand, such as cyclic prefix based (CP-OFDM), and discrete Fourier transform spread based (DFT-S-OFDM) schemes, which have limiting effects on PAPR, the PAPR is still as high as 13 dB. This value increases when the bandwidth is increased. Moreover, in LTE-Advance and 5G systems, in order to increase the bandwidth, and data-rate, carrier aggregation technology is used which increases the PAPR the same way that bandwidth increment does; therefore, it is essential to employ PAPR reduction in signal processing stage before passing the signal to PA. In this paper, we investigate the performance of an innovative peak shrinking and interpolation (PSI) technique for reducing peak to average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) based signals at waveform generation stage. The main idea behind the PSI technique is to extract high peaks, scale them down, and interpolate them back into the signal. It is shown that PSI technique is a possible candidate for reducing PAPR without compromising on computational complexity, compatible for existing and future telecommunication systems such as 4G, 5G, and beyond. In this paper, the PSI technique is tested with variety of signals in terms of inverse fast Fourier transform (IFFT) length, type of the signal modulation, and applications. Additional work has been carried out to compare the proposed technique with other promising PAPR reduction techniques. This paper further validates the PSI technique through experimental measurement with a power amplifier (PA) test bench and achieves an adjacent channel power ratio (ACPR) of less than –55 dBc. Results showed improvement in output power of PA versus given input power, and furthermore, the error vector magnitude (EVM) of less than 1% was achieved when comparing of the signal after and before modification by the PSI techniqu

A Physical Layer Security (PLS) approach through Address Fed Mapping Crest Factor Reduction applicable for 5G/6G signals

The privacy and security of 5G/6G infrastructures are receiving great attention together with power consumption and efficiency. Here, Physical Layer Security (PLS) is considered and a technique named Address Fed Mapping (AFM) is proposed which not only enhances the physical layer security, but also reduces the effect of high Peak to Average Power Ratio (PAPR), which results in efficiency improvement in OFDM based signals used in beyond 5G and 6G. The AFM is designed based on the idea of randomly generated signals, modifying the original signal to reduce PAPR. Instead of a typical randomization algorithm, a unique key is generated based on Channel response that is known only transmitter-receiver pairs. This key is used to pick a signal and send it. It is shown that the proposed AFM technique reduces PAPR, which improves the energy efficiency of the system

PAPR Reduction for Improved Efficiency of OFDM Modulation for Next Generation Communication Systems

Highly linear power amplifiers are required for transferring   large amount of data for future communication. Orthogonal frequency division multiplexing (OFDM) provides high data rate transmission capability with robustness to radio channel impairments. It has been widely accepted for future communication for different services. But, it suffers from high value of peak-to-average power ratio (PAPR). High value of PAPR drives high power amplifier into its saturation region and causes it to operate in the nonlinear region.  In this paper, comparative study of four different PAPR reduction techniques: clipping and filtering (CF), selective mapping  method (SLM), partial transmit sequence (PTS) and DFT- spread technique  have been done. Mathematical modeling and Matlab simulations have been performed to arrive at the results with 4 QAM modulation format and 1024 number of sub carriers. At 0.01 % of complementary cumulative distribution function (CCDF) significant reduction of 11.3, 3.5, 3.4 and 1.0 dB have been obtained with DFT- spread, SLM, PTS and CF techniques respectively

PAPR Reduction with Amplitude Clipping & Filtering, SLM & PTS Techniques for MIMO-OFDM System: A Brief Review

Nowadays MIMO-OFDM has become a popular technique for 4G wireless communications. OFDM technique combined with multiple antennas at transmitter and receiver point to high data rate, low complexity and diversity. One of the major drawbacks in the MIMO-OFDM is high peak-to-average power ratio (PAPR).Clipping & Filtering, Selective Mapping (SLM), Partial Transmit Sequence (PTS) are some of the techniques which minimizes the PAPR. In this review paper, different techniques of PAPR reduction have been studied

Digital signal processing techniques for peak-to-average power ratio mitigation in MIMO–OFDM systems

The focus of this thesis is to mitigate the very large peak-to-average transmit power ratios (PAPRs) inherent to conventional orthogonal frequency division multiplexing (OFDM) systems, particularly in the context of transmission over multi-input multi-output (MIMO) wireless broadband channels. This problem is important as a large PAPR generally needs an expensive radio frequency (RF) power amplifier at the transmitter due to the requirement for linear operation over a wide amplitude range and such a cost would be compounded when multiple transmit antennas are used. Advanced signal processing techniques which can reduce PAPR whilst retain the integrity of digital transmission therefore have considerable potential for application in emergent MIMO–OFDM wireless systems and form the technical contributions of this study. [Continues.

PAPR Reduction and Data Security Improvement for OFDM Technique Using Chaos System

Orthogonal Frequency Division Multiplexing (OFDM) is the most popular multicarrier technique because it produces several advantages such as higher spectral efficiency, high transmission rate, robustness to fading channel and etc.. In this technique, the data is carrying by multiple orthogonal subcarriers. If all subcarriers are adding together with the same phase, it will result high Peak to Average Power Ratio (PAPR). Higher value of PAPR makes low power efficiency, several degradation of performance in the transmit power amplifier and increase the complexity of converters. It is important to decrease PAPR for avoid these problems. Another requirement of the modern communication system is the security of transmission data. All these issues make strong motivation for building algorithm to improve performance and security of OFDM system. In this paper, a proposed algorithm is presented to both reduce PAPR and secure the OFDM signal by generating several Aperiodic PseudoRandom Binary Sequences (APRBSs) using chaos system. The proposed algorithm is scrambling the information by APRBSs, and one sequence is chosen for transmission which has smallest PAPR value. To inform receiver which sequence had been sent, a Side Information (SI) is enclosed with the transmitted sequence. Because SI very important at receiver, convolutional code with Viterbi-Soft Decision Decoding (V-SDD) is used to protect it against channel distortion. Simulation results state the proposed algorithm produces excellent PAPR reduction performance and approximately gives the same Bit Error Rate (BER) of the conventional OFDM system over AWGN and fading channels. In addition to get better performance, the proposed algorithm is providing a good data security due to chaos system. MATLAB program is used to build the proposed OFDM system and get the simulation results