# US 12,007,467 B2 · Doppler-division multiplexing MIMO radar signal reconstruction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,467 B2 - Document ID: US12007467B2 - Status: Granted - Kind: B2 - Application number: 17/510,780 - Filed: 2021-10-26 - Published: 2023-04-27 - Granted: 2024-06-11 - Earliest claimed: 2021-10-26 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: Byung Kwon Park; Sang Ho Nam - Web page: https://patentgrep.com/patent/US12007467B2 ## CPC - G01S 13/343: {using sawtooth modulation} - G01S 13/524: based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi - G01S 7/356: {involving particularities of FFT processing} - G01S 7/403: {in azimuth, i.e. in the horizontal plane} - G01S 13/32: using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated - G01S 13/325: {using transmission of coded signals, e.g. P.S.K. signals} - G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - G01S 13/584: {adapted for simultaneous range and velocity measurements} - G01S 13/931: of land vehicles - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A multiple-input multiple-output (MIMO) radar system, including: a plurality of transmit channels configured to sequentially transmit signals with transmit-channel-designated Doppler division multiplexing (DDM) modulations; and processing circuitry configured to: determine, for each of the transmit channels, an impulse response of phase modulation errors due to DDM coupling of the respective transmit channel from each of the other transmit channels; and generate, based on the impulse response, a reconstruction matrix of modulation DDM coupling factors. ## Claims ### Claim 1 A multiple-input multiple-output (MIMO) radar system, comprising: a plurality of transmit channels configured to sequentially transmit signals with transmit-channel-designated Doppler division multiplexing (DDM) modulations; and processing circuitry configured to: determine, for each of the transmit channels, an impulse response of phase modulation errors due to DDM coupling of the respective transmit channel from each of the other transmit channels; and generate, based on the impulse response, a reconstruction matrix of modulation DDM coupling factors. ### Claim 2 (depends on 1) The MIMO radar system of claim 1, wherein the processing circuitry is further configured to: estimate the phase modulation error for each of the transmit channels due to the DDM coupling of the respective transmit channel from each of the other transmit channels. ### Claim 3 (depends on 2) The MIMO radar system of claim 2, further comprising: a test signal generator configured to generate offset frequencies for the transmit signals, which have phase offsets sequentially corresponding with transmit-channel-designated DDM segments, wherein the processing circuitry is further configured to perform fast Fourier transform (FFT) processing over a fast time axis of the transmit signals coupled to a receive channel to determine relative measured phase offsets of the transmit signals. ### Claim 4 (depends on 3) The MIMO radar system of claim 3, wherein the processing circuitry is further configured to: determine the impulse response by performing FFT processing of a phase modulation vector for each of the respective transmit channels, wherein the phase modulation vector is based on an effective relative phase difference vector of DDM segments for the respective transmit channel. ### Claim 5 (depends on 1) The MIMO radar system of claim 1, wherein the transmit signals are single tone signals. ### Claim 6 (depends on 1) The MIMO radar system of claim 1, wherein the transmit signals are frequency modulated continuous wave (FMCW) signals. ### Claim 7 (depends on 1) The MIMO radar system of claim 1, wherein the processing circuitry is further configured to: measure the phase modulation error for each of the transmit channels due to the DDM coupling of the respective transmit channel from each of the other transmit channels. ### Claim 8 (depends on 7) The MIMO radar system of claim 7, wherein the processing circuitry is further configured to: determine the impulse response by performing fast Fourier transform (FFT) processing of a phase modulation vector for each of the respective transmit channels, wherein the phase modulation vector is based on an actual relative phase difference vector of DDM segments for the respective transmit channel. ### Claim 9 (depends on 1) The MIMO radar system of claim 1, wherein the plurality of transmit channels are configured to be sequentially enabled one at a time while the other transmit channels are disabled, and the transmit signals are to be reflected by a predetermined target. ### Claim 10 (depends on 9) The MIMO radar system of claim 9, wherein the processing circuitry is further configured to: determine the impulse response for each of the transmit channels by performing fast Fourier transform (FFT) processing over a slow time axis of the transmit signals reflected by the predetermined target; and generate the reconstruction matrix based on the result of the FFT processing. ### Claim 11 (depends on 1) The MIMO radar system of claim 1, wherein the processing circuitry is further configured to: synthesize a virtual aperture array based on the reconstruction matrix of modulation DDM coupling factors. ### Claim 12 (depends on 1) The MIMO radar system of claim 1, wherein the processing circuitry is further configured to: reconstruct a real matrix of fundamental signal components of the transmit signals by multiplying the reconstruction matrix by a measured matrix, wherein the measured matrix comprises measured fundamental signal components superposed by spurious components due to DDM modulation coupling between the transmit channels; and synthesize a virtual aperture array based on the reconstructed real matrix. ### Claim 13 (depends on 1) The MIMO radar system of claim 1, further comprising: at least two transmit channels, wherein the first transmit channel is unmodulated, and the second transmit channel is modulated with binary phase shift keying (BPSK) modulation. ### Claim 14 (depends on 13) The MIMO radar system of claim 13, further comprising: at least three transmit channels, wherein the third transmit channel is modulated with quadrature phase shift keying (QPSK) modulation. ### Claim 15 A multiple-input multiple-output (MIMO) radar processing method, comprising: a plurality of transmit channels sequentially transmitting signals with transmit-channel-designated Doppler division multiplexing (DDM) modulations; processing circuitry determining, for each of the transmit channels, an impulse response of phase modulation errors due to DDM coupling of the respective transmit channel from each of the other transmit channels; and the processing circuitry generating, based on the impulse response, a reconstruction matrix of modulation DDM coupling factors. ### Claim 16 (depends on 15) The MIMO radar processing method of claim 15, further comprising: the processing circuitry estimating the phase modulation error for each of the transmit channels due to the DDM coupling of the respective transmit channel from each of the other transmit channels. ### Claim 17 (depends on 16) The MIMO radar processing method of claim 16, further comprising: a test signal generator generating offset frequencies for the transmit signals, which have phase offsets sequentially corresponding with transmit-channel-designated DDM segments; and the processing circuitry performing fast Fourier transform (FFT) processing over a fast time axis of the transmit signals coupled to a receive channel to determine relative measured phase offsets of the transmit signals. ### Claim 18 (depends on 17) The MIMO radar processing method of claim 17, further comprising: the processing circuitry determining the impulse response by performing FFT processing of a phase modulation vector for each of the respective transmit channels, wherein the phase modulation vector is based on an effective relative phase difference vector of DDM segments for the respective transmit channel. ### Claim 19 (depends on 15) The MIMO radar processing method of claim 15, further comprising: the processing circuitry measuring the phase modulation error for each of the transmit channels due to the DDM coupling of the respective transmit channel from each of the other transmit channels. ### Claim 20 (depends on 19) The MIMO radar processing method of claim 19, further comprising: the processing circuitry determining the impulse response by performing fast Fourier transform (FFT) processing of a phase modulation vector for each of the respective transmit channels, wherein the phase modulation vector is based on an actual relative phase difference vector of DDM segments for the respective transmit channel. ### Claim 21 (depends on 15) The MIMO radar processing method of claim 15, wherein the plurality of transmit channels are configured to be sequentially enabled one at a time while the other transmit channels are disabled, and the transmit signals are to be reflected by a predetermined target. ### Claim 22 (depends on 21) The MIMO radar processing method of claim 21, further comprising: the processing circuitry determining the impulse response for each of the transmit channels by performing fast Fourier transform (FFT) processing over a slow time axis of the transmit signals reflected by the predetermined target; and the processing circuitry generating the reconstruction matrix based on the result of the FFT processing. ### Claim 23 (depends on 15) The MIMO radar processing method of claim 15, further comprising: the processing circuitry synthesizing a virtual aperture array based on the reconstruction matrix of modulation DDM coupling factors. ### Claim 24 (depends on 15) The MIMO radar processing method of claim 15, further comprising: the processing circuitry reconstructing a real matrix of fundamental signal components of the transmit signals by multiplying the reconstruction matrix by a measured matrix, wherein the measured matrix comprises measured fundamental signal components superposed by spurious components due to DDM modulation coupling between the transmit channels; and the processing circuitry synthesizing a virtual aperture array based on the reconstructed real matrix.