PAPR Reduction in OFDM Signals by Self-Adjustment Gain Method

Abstract

OFDM in 5G wireless communication networks has the advantages of a high transmission volume and data rate. However, the problem of a high peak-to-average power ratio (PAPR) of OFDM signals may lead to serious performance degradation and distortion in the high-power amplifier at the transmitter. In this paper, with the clipping process, the self-adjustment gain (SAG) method is proposed, to tune up the positions of the clipped signals, for reducing the PAPR of OFDM signals without increasing the error probability. The distance between the estimated and clipped signal points in the signal space is measured. An updated process is developed to produce the new signal points based on the measured distance and the self-adjustment gain that is obtained from the clipping noise power and measurement power. The simulation results show that for QPSK/OFDM, SAG reduces up to 2 dB and 0.7 dB more PAPR than ACE with one and three iterations, respectively. For 16QAM/OFDM, SAG reduces up to 1.3 dB and 0.5 dB more PAPR than ACE with one and three iterations, respectively. SAG also outperforms the active constellation extension, with the projection onto convex sets (ACE-POCS) and gradient project (SGP) methods in first two iterations. Hence, the proposed method really reduces the PAPR value more effectively, within an acceptable error probability, and its computational complexity is also much lower in comparison with those methods based on the active constellation extension (ACE) with iterations.

Modified Method of PAPR Reduction Using Clipping and Filtering for Image Transmission with OFDM

“…While the second is PAPR reduction by changing the subcarrier's phase of WOFDM. A self-adjustment gain scheme for decreasing PAPR values without increasing error probability is presented in [20]. This technique changes each cut sign to highlight another position, as per the proportions between the remaining and framework powers for diminishing the framework blunders, which have the impact of controlling the situation with information after input of the section signals.…”

“…Different proposed techniques used for PAPR reduction are illustrated in [19][20][21][22][23], which are divided into three sets as shown in Figure 1. One of the simplest and most pragmatic approaches is clipping and filtering, which can limit the signal to the transmitter to eliminate the occurrence of high peaks above a certain level.…”

Análise do Desempenho de Sistemas DFT-s-GFDM em Canais FSC

“…Outro fator importante é a alta emissão fora de faixa provocada pela descontinuidade no sinal modulado com símbolos Quadrature Amplitude Modulation (QAM), impedindo a exploração do OFDM em bandas fragmentadas. Algumas soluções para esta questão envolvem pré-codificação Discrete Fourier Transform (DFT), clipping, Partial Transmission Sequence (PTS), Selective Mapping (SLM), redes neurais e lógica fuzzy [5], [6], [7], [8], [9]. Dentre estas, a précodificação DFT é a mais utilizada.…”