# US 2019/0380101 A1 · System and method for iq mismatch calibration and compensation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0380101 A1 - Document ID: US20190380101A1 - Status: Published application - Kind: A1 - Application number: 16/549,996 - Filed: 2019-08-23 - Published: 2019-12-12 - Earliest claimed: 2017-02-22 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Tiangao Gou; Pranav Dayal; Niranjan Ratnakar; Gennady Feygin; Jungwon Lee - Web page: https://patentgrep.com/patent/US20190380101A1 ## CPC - H04W 56/004: {compensating for timing error of reception due to propagation delay} - H03D 3/009: {Compensating quadrature phase or amplitude imbalances} - H04L 27/364: {Arrangements for overcoming imperfections in the modulator, e.g. quadrature error or unbalanced I and Q levels} - H03D 2200/0045: Calibration of demodulators - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H03D: DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER (masers, lasers H01S; circuits capable of acting both as modulator and demodulator H03C; details applicable to both modulators and frequency-changers H03C; demodulating pulses H03K9/00; transforming types of pulse modulation H03K11/00; coding, decoding or code conversion, in general H03M; repeater stations H04B7/14; demodulators adapted for AC systems of digital information transmission H04L27/00; synchronous demodulators adapted for colour television H04N9/66) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method for providing IQ mismatch (IQMM) compensation includes: sending a single tone signal at an original frequency; determining a first response of an impaired signal at the original frequency and a second response of the impaired signal at a corresponding image frequency; determining an estimate of a frequency response of the compensation filter at the original frequency based on the first response and the second response; repeating the steps of sending the single tone signal, determining the first response and the second response, and determining the estimate of the frequency response of the compensation filter by sweeping the single tone signal at a plurality of steps to determine a snapshot of the frequency response of the compensation filter; converting the frequency response of the compensation filter to a plurality of time-domain filter taps of the compensation filter by performing a pseudo-inverse of a time-to-frequency conversion matrix; and determining a time delay that provides a minimal LSE for the corresponding time domain filter taps. ## Claims ### Claim 1 A method for providing IQ mismatch (IQMM) compensation, the method comprising: estimating filter coefficients corresponding to a plurality of time-domain filter taps of a compensation filter before reception of normal signals based on a static calibration scheme; setting each of the plurality of time-domain filter taps with a corresponding estimated filter coefficient; setting an initial value for a time delay tap to zero or based an estimated value obtained using the static calibration scheme; and estimating a filter coefficient for the time delay tap during reception of a normal signal based on an iterative scheme using an adaptive filter. ### Claim 2 (depends on 1) The method of claim 1, wherein the IQMM is a frequency-dependent IQMM (FD-IQMM) or a frequency-independent IQMM (FI-IQMM). ### Claim 3 (depends on 1) The method of claim 1, wherein the compensation filter is a complex-valued filter. ### Claim 4 (depends on 1) The method of claim 1, wherein the compensation filter is a real-valued filter including a real-valued scaling factor that feeds a delayed version of an in-phase (I) path into an output of a real-valued filter of a quadrature (Q) path. ### Claim 5 (depends on 1) The method of claim 1, wherein the compensation filter is implemented in a receiver of a wireless communication system. ### Claim 6 (depends on 1) The method of claim 1, wherein the compensation filter includes a baseband digital filter. ### Claim 7 (depends on 1) The method of claim 1, further comprising selecting a finite number of time-domain filter taps among the plurality of time-domain filter taps. ### Claim 8 (depends on 7) The method of claim 7, wherein the finite number of time-domain filter taps includes one or more positive filter taps. ### Claim 9 (depends on 8) The method of claim 8, further comprising adding an extra time delay in a feedforward path of the compensation filter to include a negative filter tap. ### Claim 10 (depends on 1) The method of claim 1, wherein the time delay is estimated based on a plurality of minimal least square errors (LSEs) for the corresponding time-domain filter taps. ### Claim 11 An apparatus comprising: a signal generator for generating and sending a single tone signal at an original frequency; a compensator including a time delay and a plurality of time-domain filter taps; and a compensation logic for performing a static calibration of the compensator, wherein the compensation logic is configured to: estimate filter coefficients corresponding to the plurality of time-domain filter taps of a compensation filter before reception of normal signals based on a static calibration scheme; set each of the plurality of time-domain filter taps with a corresponding estimated filter coefficient; set an initial value for a time delay tap to zero or based an estimated value obtained using the static calibration scheme; and estimate a filter coefficient for the time delay tap during reception of a normal signal based on an iterative scheme using an adaptive filter. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the IQMM is a frequency-dependent IQMM (FD-IQMM) or a frequency-independent IQMM (FI-IQMM). ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the compensation filter is a complex-valued filter. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein the compensation filter is a real-valued filter including a real-valued scaling factor that feeds a delayed version of an in-phase (I) path into an output of a real-valued filter of a quadrature (Q) path. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the compensation filter is implemented in a receiver of a wireless communication system. ### Claim 16 (depends on 11) The apparatus of claim 11, wherein the compensation filter includes a baseband digital filter. ### Claim 17 (depends on 11) The apparatus of claim 11, wherein the compensation logic is further configured to select a finite number of time-domain filter taps among the plurality of time-domain filter taps. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the finite number of time-domain filter taps includes one or more positive filter taps. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the compensation logic is further configured to add an extra time delay in a feedforward path of the compensation filter to include a negative filter tap. ### Claim 20 (depends on 11) The apparatus of claim 11, wherein the time delay is estimated based on a plurality of minimal least square errors (LSEs) for the corresponding time-domain filter taps.