Patent ID: 7319723

Claim:
A method for controlling a value of symbols in order to reduce a peak-to-average power ratio (PAPR) in a transmitter for a mobile communication system for generating OFDM (Orthogonal Frequency Division Multiplexing) modulation symbols by performing IFFT (Inverse Fast Fourier Transform) on input data, the method comprising the steps of; pre-emphasizing a symbol value S(n) with different gains according to whether the symbol value S(n) is less than a first prescribed reference value k 1 or not; and converting a digital value S pre of the pre-emphasized symbol value into an analog signal and amplifying the analog signal at a prescribed gain, wherein the pre-emphasized symbol value for a case where the symbol value S(n) is less than the first prescribed reference value k 1 (0≦S(n)≦k 1 ) is defined as S pre ⁢ ( n ) = k 2 k 1 ⁢ S ⁢ ( n ) where k 2 is a second prescribed reference value and the pre-emphasized symbol value for a case where the symbol value S(n) is greater than or equal to the first prescribed reference value k 1 (k 1 ≦S(n)≦L) is defined as S pre ⁢ ( n ) = L - k 2 L - k 1 ⁢ S ⁢ ( n ) + L ⁢ ( 1 - L - k 2 L - k 1 ) where L is a maximum value of the S(n); and wherein the prescribed reference value k 1 is amplitude defined as a pre-emphasis change point.