Patent ID: 8675750
Filing Date: 2014-03-18
Classification: H04L

Abstract:
1. An apparatus for reducing a peak to average power ratio (PAPR), the apparatus comprising: an orthogonal frequency division multiplexing (OFDM) symbol transforming unit sequentially transforming an OFDM symbol in a time domain obtained through an inverse fast Fourier transform (IFFT) to generate a plurality of OFDM symbols; a peak power measuring unit measuring peak powers of each of the OFDM symbol and the plurality of OFDM symbols generated therefrom; and an OFDM symbol selecting unit selecting an OFDM symbol having a minimum value among the measured peak powers as a candidate OFDM symbol to be transmitted and transmitting the selected candidate OFDM symbol, wherein the OFDM symbol transforming unit generates the plurality of OFDM symbols by (a) performing a process of rotating the OFDM symbol by a predetermined angle in a complex plane and performing cyclical shifting with respect to the rotated OFDM symbol and (b) repetitively performing process (a) with respect to the cyclically shifted OFDM symbol, and wherein the OFDM symbol transforming unit performs the cyclic shifting by cyclically shifting a quadrature phase (Q) component of the rotated OFDM symbol and recombining the cyclically shifted quadrature phase (Q) component with an existing in-phase (I) component.