Computationally Efficient PAPR Reduction Schemes in OFDM-Based Satellite Communication Systems

Abstract

Due to the nonlinear characteristics of the high power amplifier (HPA), the employment of orthogonal frequency division multiplexing (OFDM) based modulation schemes results in significant amplitude and phase signal distortion due to the high peak-to-average power ratio (PAPR) nature of the OFDM. To overcome this problem, PAPR reduction methods are commonly applied at the transmitter. Among the plenitude of methods available, partial transmit sequences (PTS) and selected mapping (SLM) are the most powerful schemes. The computational complexity for these schemes is considered as the main disadvantage. In this paper, we propose a low-complexity scheme based on iterative PTS (IPTS) that employs two inverse fast Fourier transforms (IFFT) and two circulant transform matrices. Numerical results demonstrate that the proposed scheme using a partition vector for IPTS with an odd number of ones can achieve both a reduction in PAPR of approximately 2 dB and an improvement of 1.4 dB in terms of signal-to-noise ratio (SNR) to achieve a bit error rate (BER) of 10^-4. A further simplification can be achieved by omitting one of the circulant transform matrices in order to improve the computational complexity reduction ratio (CCRR) by 30% and reduce the number of side information bits by 1-bit compared with the IPTS, however, at the cost of a small reduction in PAPR and BER performance.