Patent ID: 9031159
Filing Date: 2015-05-12
Classification: H04L

Abstract:
1. A communication device that communicates with another device in orthogonal frequency-division multiplexing wireless communication, the communication device comprising: a modulator that modulates input signals by a predetermined modulation scheme to generate primary modulation signals and generates subcarrier modulation signals that are parallel signals based on the primary modulation signals; a transmission-side combiner that arranges the subcarrier modulation signals in order thereby to generate a compound matrix having each of the subcarrier modulation signals in each column thereof; a transmission-side shifter that shifts elements of each row of the compound matrix in a predetermined direction by a number of shifts of a transmission-side shift unit to which the each row belongs, based on a number of shifts set for each transmission-side shift unit of a plurality of transmission-side shift units, the each transmission-side shift unit comprising a same number of rows in the compound matrix thereby to generate a transmission-side shift matrix; a first IFFT calculator that subjects the transmission-side shift matrix to inverse fast Fourier transformation to generate an inverse transformation matrix; a maximum detector that calculates a peak-to-average power ratio of a baseband signal generated for each of columns of the inverse transformation matrix and detects a column with a highest peak-to-average power ratio among the columns of the inverse transformation matrix; a repeater that repeats processing by the transmission-side shifter, the first IFFT calculator and the maximum detector while changing the number of shifts of at least any one of the plurality of transmission-side shift units; a minimum detector that detects an inverse transformation matrix including a column with a lowest peak-to-average power ratio among columns detected by the maximum detector; and a transmitter that combines elements of each column of the inverse transformation matrix detected by the minimum detector to generate baseband signals and transmits a transmission signal based on the baseband signals.