# US 2014/0192925 A1 · Method of and apparatus for reducing papr in filter-bank multi-carrier system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192925 A1 - Document ID: US20140192925A1 - Status: Published application - Kind: A1 - Application number: 14/234,729 - Filed: 2012-07-13 - Published: 2014-07-10 - Earliest claimed: 2011-07-29 - Assignees: Alcatel Lucent - Inventors: Dong Li - Web page: https://patentgrep.com/patent/US20140192925A1 ## CPC - H04L 27/2654: {Filtering per subcarrier, e.g. filterbank multicarrier [FBMC]} - H04L 25/08: Modifications for reducing interference; Modifications for reducing effects due to line faults {; Receiver end arrangements for detecting or overcoming line faults} - H04L 27/2614: {Peak power aspects} - H04L 27/2636: {with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]} - H04L 27/26416: {Filtering per subcarrier, e.g. filterbank multicarrier [FBMC]} - H04L 27/3411: {reducing the peak to average power ratio or the mean power of the constellation; Arrangements for increasing the shape gain of a signal set} - H04L 27/362: {Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated (H04L27/366 takes precedence)} - H04L 27/38: Demodulator circuits; Receiver circuits - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The invention relates to a method of reducing Peak-to-Average. Power Ratio in a transmitting device of a filter-hank multi-carrier system, which includes the steps of: performing constellation modulation (210) on data to be transmitted; performing K-point Discrete Fourier Transform (220) on a vector composed of K constellation symbols resulting from the constellation modulation: and performing Offset-Quadrature Amplitude Modulation (230) on a data vector resulting from the Discrete Fourier Transform, wherein the parameter K represents the number of subcarriers allocated for transmission of the data to be transmitted. With the solution proposed by the invention. PAPR of a signal can be significantly reduced without adding a large number of operations to thereby improve the efficiency of a power amplification circuit, to improve effective transmission, power and to alleviate nonlinear distortion of the signal during a power amplification. ## Claims ### Claim 1 A method of reducing Peak-to-Average Power Ratio in a transmitting device of a filter-bank multi-carrier system, comprising: performing constellation modulation on data to be transmitted; performing K-point Discrete Fourier Transform on a vector composed of K constellation symbols resulting from the constellation modulation; and performing Offset-Quadrature Amplitude Modulation on a data vector resulting from the Discrete Fourier Transform, wherein the parameter K represents the number of subcarriers allocated for transmission of the data to be transmitted. ### Claim 2 (depends on 1) The method according to claim 1, wherein performing Offset-Quadrature Amplitude Modulation on a data vector resulting from the Discrete Fourier Transform comprises mapping a real part of the data vector to a first filter-bank multi-carrier symbol and mapping an imaginary part of the data vector to a second filter-bank multi-carrier symbol. ### Claim 3 (depends on 2) The method according to claim 2, wherein a phase comprised in each element of the first and the second filter-bank multi-carrier symbols is determined by a time-domain index of the filter-bank multi-carrier symbol to which the element belongs and a frequency-domain index of a corresponding subcarrier. ### Claim 4 (depends on 1) The method according to claim 1, wherein the constellation modulation in performing constellation modulation on data to be transmitted is Multiple Phase-Shift Keying or Quadrature Amplitude Modulation. ### Claim 5 (depends on 1) The method according to claim 1, wherein after performing Offset-Quadrature Amplitude Modulation on a data vector resulting from the Discrete Fourier Transform, the method further comprises: mapping filter-bank multi-carrier symbols onto the allocated K subcarriers through subcarrier mapping; and performing multi-carrier filtering on an output of the subcarrier mapping. ### Claim 6 (depends on 1) The method according to claim 1, wherein the allocated K subcarriers are successive. ### Claim 7 (depends on 5) The method according to claim 5, wherein performing multi-carrier filtering on an output of the subcarrier mapping comprises: performing M-point Inverse Discrete Fourier Transform on the output of the subcarrier mapping; and performing a polyphase filtering process on the signal after the Inverse Discrete Fourier Transform, wherein the parameter M represents the total number of subcarriers in the filter-bank multi-carrier system. ### Claim 8 (depends on 1) The method according to claim 1, wherein before performing constellation modulation on data to be transmitted, the method further comprises: performing channel encoding on the data to be transmitted. ### Claim 9 A method of reducing Peak-to-Average Power Ratio in a receiving device of a filter-bank multi-carrier system, comprising: performing Offset-Quadrature Amplitude Modulation demodulation on a signal after channel equalization; performing K-point Inverse Discrete Fourier Transform on the signal after the Offset-Quadrature Amplitude Modulation demodulation; and performing constellation modulation demodulation on the signal after the Inverse Discrete Fourier Transform, wherein the parameter K represents the number of subcarriers allocated for transmission of corresponding data to be transmitted. ### Claim 10 (depends on 9) The method according to claim 9, wherein before performing K-point Inverse Discrete Fourier Transform on the signal after the Offset-Quadrature Amplitude Modulation demodulation, the method further comprises: performing multi-carrier filtering on a received signal; performing subcarrier inverse mapping on the signal after the multi-carrier filtering; and performing the channel equalization on the signal after the subcarrier inverse mapping. ### Claim 11 (depends on 10) The method according to claim 10, wherein performing multi-carrier filtering on a received signal comprises: performing polyphase filtering on the received signal; and performing M-point Discrete Fourier Transform on the signal after the polyphase filtering, wherein the parameter M represents the total number of subcarriers in the filter-bank multi-carrier system. ### Claim 12 (depends on 9) The method according to claim 9, wherein the constellation modulation in performing constellation modulation demodulation on the signal after the Inverse Discrete Fourier Transform is Multiple Phase-Shift Keying or Quadrature Amplitude Modulation. ### Claim 13 (depends on 9) The method according to claim 9, wherein after performing constellation modulation demodulation on the signal after the Inverse Discrete Fourier Transform, the method further comprises: performing channel decoding on the signal after the constellation modulation demodulation. ### Claim 14 An apparatus for reducing Peak-to-Average Power Ratio in a transmitting device of a filter-bank multi-carrier system, comprising: a constellation modulation device configured to perform constellation modulation on data to be transmitted; a Discrete Fourier Transform device configured to perform K-point Discrete Fourier Transform on a vector composed of K constellation symbols resulting from the constellation modulation; and an Offset-Quadrature Amplitude Modulation device configured to perform Offset-Quadrature Amplitude Modulation on a data vector resulting from the Discrete Fourier Transform, wherein the parameter K represents the number of subcarriers allocated for transmission of the data to be transmitted. ### Claim 15 An apparatus for reducing Peak-to-Average Power Ratio in a receiving device of a filter-bank multi-carrier system, comprising: an Offset-Quadrature Amplitude Modulation demodulation device configured to perform Offset-Quadrature Amplitude Modulation demodulation on a signal after channel equalization; an Inverse Discrete Fourier Transform device configured to perform K-point Inverse Discrete Fourier Transform on the signal after the Offset-Quadrature Amplitude Modulation demodulation; and a constellation modulation demodulation device configured to perform constellation modulation demodulation on the signal after the Inverse Discrete Fourier Transform, wherein the parameter K represents the number of subcarriers allocated for transmission of corresponding data to be transmitted.