Controlling Peak-to-Average Power Ratio in Orthogonal Frequency Division Multiplexing System

Abstract

A major drawback of Orthogonal Frequency Division Multiplexing at the transmitter side is the high peak-to-average power ratio (PAPR) of the signal. Conventional solutions for this problem are to use a linear amplifier ( or to back-off the operating point of a nonlinear amplifier). Recently many techniques are introduced to reduce PAPR , Selected mapping (SLM) is one of the promising PAPR reduction techniques , where some statistically independent data blocks ( carrying same information ) are generated from an Orthogonal Frequency Division Multiplexing data block using a set of phase sequences and one with the lowest PAPR is chosen and transmitted .The proposed PAPR reduction scheme in this paper used Riemann sequences as a phase vectors for Selected Mapping (in the frequency domain) along with simple mathematic processing in time domain will enhanced PAPR reduction by changing the mean and variance values of the processed Orthogonal Frequency Division Multiplexing signals (Time Domain Statistical Control ) . For system with 128 sub-carriers and QPSK mapping , the proposed method shows almost 2dB and 4dB for conventional SLM and SLM with square rooting SQRT techniques, respectively.