# US 11,451,425 B2 · Peak-to-average power ratio (PAPR) reduction techniques > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,425 B2 - Document ID: US11451425B2 - Status: Granted - Kind: B2 - Application number: 17/185,603 - Filed: 2021-02-25 - Published: 2021-11-04 - Granted: 2022-09-20 - Earliest claimed: 2020-05-01 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Gokul Sridharan; Saeid Sahraei; June Namgoong; Peter Gaal; Krishna Kiran Mukkavilli; Tingfang Ji; Wei Yang - Web page: https://patentgrep.com/patent/US11451425B2 ## CPC - H04L 27/2614: {Peak power aspects} - H04L 27/2623: {Reduction thereof by clipping} - H04B 1/7102: {with transform to frequency domain} - H04L 25/03834: {using pulse shaping} - H04L 25/0384: {Design of pulse shapes (pulse shape for impulse radio H04B1/7172)} - 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]} - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04B 2201/70706: with means for reducing the peak-to-average power ratio - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Techniques for peak-to-average power ratio (PAPR) reduction are described. Wireless devices may use one or more PAPR shaping resources, such as expanded bandwidth and/or pulse-shaping filtering, for shaping a signal to reduce PAPR. For example, expanded bandwidth may be utilized for adding a cyclic affix (CA), such as may comprise a cyclic prefix (CP), cyclic suffix (CS), etc., and combinations thereof, to a frequency domain data signal to provide a CP augmented frequency domain data signal used to generate a reduced PAPR time domain data signal. Additionally or alternatively, pulse-shaping filtering may be applied to a frequency domain signal to provide a pulse-shaped frequency domain data signal used to generate a reduced PAPR time domain data signal. Other aspects and features are also claimed and described. ## Claims ### Claim 1 A method of wireless communication, comprising: generating a frequency domain data signal from a discrete Fourier transform (DFT) based on a data signal provided for the wireless communication; determining expanded bandwidth available for shaping a time domain data signal generated for the data signal; adding a cyclic affix (CA) to the frequency domain data signal to provide a CA augmented frequency domain data signal, wherein the CA occupies bandwidth of the expanded bandwidth; and generating the time domain data signal for wireless communication from an inverse discrete Fourier transform (IDFT) based on the CA augmented frequency domain signal, wherein the CA added to the frequency domain data signal is configured for peak to average power ratio (PAPR) shaping with respect to the time domain data signal. ### Claim 2 (depends on 1) The method of claim 1, wherein the CA is configured to reduce a width of pulses within the time domain data signal. ### Claim 3 (depends on 2) The method of claim 2, wherein the CA is configured to reduce overlap between the pulses within the time domain data signal. ### Claim 4 (depends on 2) The method of claim 2, wherein the CA is selected to provide the PAPR shaping. ### Claim 5 (depends on 1) The method of claim 1, further comprising: selecting a length of the CA based at least in part on the expanded bandwidth. ### Claim 6 (depends on 5) The method of claim 5, wherein the expanded bandwidth available for shaping the time domain data signal comprises frequency resources in excess to frequency resources the frequency domain data signal is mapped to. ### Claim 7 (depends on 1) The method of claim 1, further comprising: applying pulse-shaping filtering to the CA augmented frequency domain signal prior to generating the time domain data signal, wherein the pulse-shaping filtering is configured for PAPR shaping with respect to the time domain data signal. ### Claim 8 An apparatus configured for wireless communication, the apparatus comprising: at least one processor; and a memory coupled to the at least one processor, wherein the at least one processor is configured: to generate a frequency domain data signal from a discrete Fourier transform (DFT) based on a data signal provided for the wireless communication; to determine expanded bandwidth available for shaping a time domain data signal generated for the data signal; to add a cyclic affix (CA) to the frequency domain data signal to provide a CA augmented frequency domain data signal, wherein the CA occupies bandwidth of the expanded bandwidth; and to generate the time domain data signal for wireless communication from an inverse discrete Fourier transform (IDFT) based on the CA augmented frequency domain signal, wherein the CA added to the frequency domain data signal is configured for peak to average power ratio (PAPR) shaping with respect to the time domain data signal. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the CA is configured to reduce a width of pulses within the time domain data signal. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the CA is configured to reduce overlap between the pulses within the time domain data signal. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein a length of the CA is selected to provide the PAPR shaping. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein the at least one processor is further configured: to select a length of the CA based at least in part on the expanded bandwidth. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the expanded bandwidth available for shaping the time domain data signal comprises frequency resources in excess to frequency resources the frequency domain data signal is mapped to. ### Claim 14 (depends on 8) The apparatus of claim 8, wherein the at least one processor is further configured: to apply pulse-shaping filtering to the CA augmented frequency domain signal prior to generating the time domain data signal, wherein the pulse-shaping filtering is configured for PAPR shaping with respect to the time domain data signal. ### Claim 15 A method of wireless communication, comprising: transmitting, by a first wireless device to a second wireless device, peak to average power ratio (PAPR) shaping capability information for use in implementing PAPR reduction, wherein the PAPR shaping capability information indicates at least one of a particular PAPR pulse-shaping filter configuration in use by the first wireless device or one or more PAPR pulse-shaping filter configurations available to the first wireless device; generating, by the first wireless device, a frequency domain data signal from a discrete Fourier transform (DFT) based on a data signal provided for the wireless communication; applying, by the first wireless device implementing a pulse-shaping filter configured in correspondence with the PAPR shaping capability information, pulse-shaping filtering to the frequency domain data signal to generate a pulse-shaped frequency domain data signal; and generating, by the first wireless device, a time domain data signal for wireless communication from an inverse discrete Fourier transform (IDFT) based on the pulse-shaped frequency domain data signal, wherein the pulse-shaping filtering is configured for PAPR shaping with respect to the time domain data signal. ### Claim 16 (depends on 15) The method of claim 15, wherein the pulse-shaping filtering uses a pulse-shaping filter with a fast-decaying time-domain tail. ### Claim 17 (depends on 16) The method of claim 16, wherein the pulse-shaping filter comprises a Hanning filter. ### Claim 18 (depends on 15) The method of claim 15, further comprising: applying a cyclic affix (CA) to the frequency domain data signal prior to generating the time domain data signal to provide a CA augmented frequency domain data signal, wherein the CA added to the frequency domain data signal is configured for PAPR shaping with respect to the time domain data signal. ### Claim 19 (depends on 18) The method of claim 18, wherein the CA is configured to reduce a width of pulses within the time domain data signal. ### Claim 20 (depends on 19) The method of claim 19, wherein the CA is configured to reduce overlap between the pulses within the time domain data signal, a length of the CA is selected to provide the PAPR shaping, or a combination thereof. ### Claim 21 (depends on 18) The method of claim 18, further comprising: determining expanded bandwidth available for shaping the time domain data signal; and selecting a length of the CA based at least in part on the expanded bandwidth. ### Claim 22 (depends on 21) The method of claim 21, wherein the expanded bandwidth comprises frequency resources in excess to frequency resources the frequency domain data signal is mapped to. ### Claim 23 An apparatus configured for wireless communication, the apparatus comprising: at least one processor; and a memory coupled to the at least one processor, wherein the at least one processor is configured: to transmit, by a first wireless device to a second wireless device, peak to average power ratio (PAPR) shaping capability information for use in implementing PAPR reduction, wherein the PAPR shaping capability information indicates at least one of a particular PAPR pulse-shaping filter configuration in use by the first wireless device or one or more PAPR pulse-shaping filter configurations available to the first wireless device; to generate, by the first wireless device, a frequency domain data signal from a discrete Fourier transform (DFT) based on a data signal provided for the wireless communication; to apply, by the first wireless device implementing a pulse-shaping filter configured in correspondence with the PAPR shaping capability information, pulse-shaping filtering to the frequency domain data signal to generate a pulse-shaped frequency domain data signal; and to generate, by the first wireless device, a time domain data signal for wireless communication from an inverse discrete Fourier transform (IDFT) based on the pulse-shaped frequency domain data signal, wherein the pulse-shaping filtering is configured for PAPR shaping with respect to the time domain data signal. ### Claim 24 (depends on 23) The apparatus of claim 23, wherein the pulse-shaping filtering uses a pulse-shaping filter with a fast-decaying time-domain tail. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the pulse-shaping filter comprises a Hanning filter. ### Claim 26 (depends on 23) The apparatus of claim 23, wherein the at least one processor is further configured: to apply a cyclic affix (CA) to the frequency domain data signal prior to generating the time domain data signal to provide a CA augmented frequency domain data signal, wherein the CA added to the frequency domain data signal is configured for PAPR shaping with respect to the time domain data signal. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the CA is configured to reduce a width of pulses within the time domain data signal. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein the CA is configured to reduce overlap between the pulses within the time domain data signal, a length of the CA is selected to provide the PAPR shaping, or a combination thereof. ### Claim 29 (depends on 26) The apparatus of claim 26, wherein the at least one processor is further configured: to determine expanded bandwidth available for shaping the time domain data signal; and to select a length of the CA based at least in part on the expanded bandwidth. ### Claim 30 (depends on 29) The apparatus of claim 29, wherein the expanded bandwidth comprises frequency resources in excess to frequency resources the frequency domain data signal is mapped to.