# US 10,374,843 B2 · Method and system for designing a waveform for data communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,843 B2 - Document ID: US10374843B2 - Status: Granted - Kind: B2 - Application number: 15/557,956 - Filed: 2015-07-16 - Published: 2018-02-22 - Granted: 2019-08-06 - Earliest claimed: 2015-04-29 - Assignees: Indian Institute of Technology Hyderabad - Applicants: Indian Institute of Technology Hyderabad - Inventors: Kiran Kumar Kuchi - Web page: https://patentgrep.com/patent/US10374843B2 ## CPC - H04L 25/03834: {using pulse shaping} - H04B 1/69: Spread spectrum techniques - H04B 1/7172: {Pulse shape (in general H04L25/03834)} - H04L 25/0212: {of impulse response} - H04L 27/2003: {for continuous phase modulation (frequency shift keying H04L27/10)} - H04L 27/2082: {for offset or staggered quadrature phase shift keying} - H04L 27/2607: {Cyclic extensions} - H04L 27/2627: {Modulators} - H04L 27/264: {Pulse-shaped multi-carrier, i.e. not using rectangular window} - H04L 27/36: Modulator circuits; Transmitter circuits - H04B 1/02: Transmitters - H04L 27/2014: {in which the phase changes in a piecewise linear manner during each symbol period, e.g. minimum shift keying, fast frequency shift keying (H04L27/201 takes precedence)} - 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: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract Embodiments herein disclose a method and system for designing a waveform for data communication. The method includes applying, by a phase rotation applying unit, a constellation specific phase rotation between consecutive data symbols in a data stream to obtain a constellation rotated data stream. Further, the method includes introducing, by a frequency domain pulse shaping filter, an inter symbol interference (ISI) between modulated data symbols of the constellation rotated data stream, such that the ISI develops the waveform of the constellated rotated data stream to be transmitted. ## Claims ### Claim 1 A method for designing a waveform for data communication, the method comprising: applying, by a phase rotator, a constellation specific phase rotation between consecutive data symbols in a data stream to obtain a constellation rotated data stream; obtaining, by a repeater, a spread signal from the constellation rotated data stream in a frequency domain; and applying, by a controller, a frequency domain pulse shaping filter to the spread signal, wherein the frequency domain pulse shaping filter is obtained using a Discrete Fourier transform (DFT) of a sampled linearized Gaussian pulse. ### Claim 2 (depends on 1) The method of claim 1, comprising: computing, by the controller, a multi-point DFT of the constellation rotated data stream. ### Claim 3 (depends on 1) The method of claim 1, wherein the spread signal is obtained by repeating the constellation rotated data stream in the frequency domain. ### Claim 4 (depends on 1) The method of claim 1, wherein the DFT is a multi-point two-sided DFT of the sampled linearized Gaussian pulse, wherein the sampled linearized Gaussian pulse is obtained by sampling a linearized Gaussian pulse using an over-sampling factor. ### Claim 5 (depends on 4) The method of claim 4, wherein the multi-point two-sided DFT is computed based on the over-sampling factor and a number of the modulated data symbols. ### Claim 6 (depends on 4) The method of claim 4, wherein the oversampling factor is equal to one or greater than one. ### Claim 7 (depends on 1) The method of claim 1, wherein the frequency domain pulse shaping filter increases bandwidth of the spread signal when the over sampling factor is greater than one. ### Claim 8 (depends on 1) The method of claim 1, comprising: adding, by the controller, at least one of a cyclic prefix and a cyclic suffix to the data stream after performing an Inverse Fast Fourier transform (IFFT) is applied on the subcarrier mapped signal. ### Claim 9 (depends on 1) The method of claim 1, further comprising: adding, by the controller, at least one of a cyclic prefix and a cyclic suffix to the data stream after performing an IFFT; and converting, by a digital-analog converter, the data stream from a digital signal obtained from the IFFT to an analog signal after adding at least one of a cyclic prefix and a cyclic suffix. ### Claim 10 (depends on 8) The method of claim 8, comprising: applying, by a window applying unit, a window function on the data stream upon addition of at least one of the cyclic prefix and the cyclic suffix to the data stream. ### Claim 11 (depends on 1) The method of claim 1, wherein the data stream is mapped to one of a localized subcarrier and a distributed sub-carrier. ### Claim 12 (depends on 1) The method of claim 1, wherein the data stream is transmitted for multiple users occupying one of non-overlapping subcarriers, partially overlapping subcarriers, and fully overlapping subcarriers. ### Claim 13 A transmitter for designing a waveform for data communication, the transmitter comprising: a phase rotator configured to apply a constellation specific phase rotation between consecutive data symbols in a data stream to obtain a constellation rotated data stream; and a repeater configured to obtain a spread signal from the constellation rotated data stream in a frequency domain; a controller configured to apply a frequency domain pulse shaping filter configured to the spread signal, wherein the frequency domain pulse shaping filter is obtained using a Discrete Fourier transform (DFT) of a sampled linearized Gaussian pulse. ### Claim 14 (depends on 13) The transmitter of claim 13, wherein the controller is configured to compute a multi-point Discrete Fourier Transform (DFT) of the constellation rotated data stream. ### Claim 15 (depends on 13) The transmitter of claim 13, wherein the spread signal is obtained repeating the constellation rotated data stream in a frequency domain. ### Claim 16 (depends on 13) The transmitter of claim 13, wherein the DFT is a multi-point two-sided DFT of the sampled linearized Gaussian pulse, wherein the sampled linearized Gaussian pulse is obtained by sampling a linearized Gaussian pulse using an over-sampling factor. ### Claim 17 (depends on 16) The transmitter of claim 16, wherein the multi-point two-sided DFT is computed based on the over-sampling factor and a number of the modulated data symbols. ### Claim 18 (depends on 16) The transmitter of claim 16, wherein the oversampling factor is equal to one or greater than one. ### Claim 19 (depends on 13) The transmitter of claim 13, wherein the frequency domain pulse shaping filter increases bandwidth of the spread signal when the over sampling factor is greater than one. ### Claim 20 (depends on 13) The transmitter of claim 13, wherein the controller is configured to add at least one of a cyclic prefix and a cyclic suffix to the data stream after performing an inverse Fast Fourier transform (IFFT) on the data stream. ### Claim 21 (depends on 13) The transmitter of claim 13, wherein the transmitter comprises: the controller further configured to add at least one of a cyclic prefix and a cyclic suffix to the data stream after performing an IFFT; and a digital-to analog signal converter configured to convert the data stream from a digital signal obtained from the IFFT to an analog signal after adding at least one of a cyclic prefix and a cyclic suffix. ### Claim 22 (depends on 13) The transmitter of claim 13, wherein the transmitter is configured to apply a window function on the data stream upon addition of at least one of the cyclic prefix and the cyclic suffix to the data stream. ### Claim 23 (depends on 13) The transmitter of claim 13, wherein the data stream is mapped to one of a localized subcarrier and a distributed sub-carrier. ### Claim 24 (depends on 13) The transmitter of claim 13, wherein the data stream is transmitted for multiple users occupying one of non-overlapping subcarriers, partially overlapping subcarriers, and fully overlapping subcarriers.