Modified Peak Clipping and Compressed Sensing Recovery Scheme in OFDM System In this paper, a modified peaktoaverage power ratio (PAPR) reduction scheme based on compressed sensing (CS) in OFDM is proposed. In previous papers, the clipping and filtering (CF) approach was used to reduce the PAPR of the oversampled signal. In this paper, the peak cancellation signal (PCS) is analyzed as a series of parabolic pulse under oversampling constraints. The single pulse can actually clip several adjacent peaks at one time, which inspires us to modify the traditional CF approach in CS recovery scheme. It is known that the performance of the CS is highly related to the sparsity of the recovered signal. The proposed clipping method could dramatically improve the sparsity of the PCS when oversampling is considered and can also reduce the computational complexity to O(N) without FFT and IFFT in the process while the PAPR performance can also improved. Meanwhile, a corresponding modified PCS recovery method is proposed based on CS theory to recover the sparse PCS before OutofBand (OOB) filtering. It shows better BER performance compared with traditional CS recovery method which tries to recover the PCS after OOB filtering.

Optimal SLM PAPR Reduction based on IQComplex Data Symbol Components To overcome the significant but unpredicted increase in the peaktoaverage power ratio (PAPR) in the presence of an OFDM system, in this paper, a new implementation of an SLM scheme is represented. The effects of the candidate phase vectors on both the real and imaginary parts of the complex data symbols are discussed. Hence, instead of modifying the generated complex data symbol as a single component, the real and imaginary parts are modified independently using a corresponding phase element among a commonly generated phase vector. After applying an inverse fast Fourier transform (IFFT) for the real, imaginary, and original baseband vectors, the (most) minimum peaktoaveragepower ratio (PAPR) for each part is observed. The phase vector that introduces the most minimal PAPR is considered to convert the original data block for transmission. This technique is called the optimal IQSLM scheme. According to the results obtained, the CCDF PAPR performance of the proposal acquires greater decibel reduction than a conventional SLM (conv.SLM) method at different subcarrier length N and candidate phase vectors U. In addition, at different levels of inputbackoff (IBO), the power spectral density (PSD) of the original and modified OFDM signals are represented, where the PSD of the proposal shows the best outofband characteristic against conv.SLM.