# US 10,873,360 B2 · Self-interference cancellation system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,360 B2 - Document ID: US10873360B2 - Status: Granted - Kind: B2 - Application number: 16/364,643 - Filed: 2019-03-26 - Published: 2020-10-01 - Granted: 2020-12-22 - Earliest claimed: 2019-03-26 - Assignees: Intel Corporation - Applicants: Intel Corporation - Inventors: Ritesh Bhat; Stefano Pellerano; Brent Carlton - Web page: https://patentgrep.com/patent/US10873360B2 ## CPC - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H04B 1/123: {using adaptive balancing or compensation means (adaptive filter circuits and algorithms H03H)} - H04B 15/005: {Reducing noise, e.g. humm, from the supply} - H04L 5/1461: {Suppression of signals in the return path, i.e. bidirectional control circuits} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Systems, methods, and circuitries are disclosed for performing self-interference cancellation in a transceiver. In one example, a self-interference cancellation system includes a cancellation signal circuitry, cancellation circuitry, down-conversion circuitry, and an LO derivation circuitry. The cancellation signal circuitry is configured to use a cancellation transmit (TX) local oscillator (LO) signal to up-convert a baseband transmit leakage replica signal to generate a cancellation signal. The cancellation circuitry is configured to combine the cancellation signal with a received signal to generate a corrected received signal. The down-conversion circuitry is configured to use a receive (RX) LO signal to down-convert the corrected received signal to generate a baseband received signal. The LO derivation circuitry is configured to derive the cancellation TX LO signal and the RX LO signal from a common LO signal. ## Claims ### Claim 1 A self-interference cancellation system, comprising: a cancellation signal circuitry configured to use a cancellation transmit (TX) local oscillator (LO) signal to up-convert a baseband transmit leakage replica signal to generate a cancellation signal; a cancellation circuitry configured to combine the cancellation signal with a received signal to generate a corrected received signal; a receive chain configured to use a receive (RX) LO signal to down-convert the corrected received signal to generate a baseband corrected received signal; and an LO derivation circuitry configured to derive the cancellation TX LO signal and the RX LO signal from a common LO signal. ### Claim 2 (depends on 1) The self-interference cancellation system of claim 1, wherein the RX LO signal is the common LO signal and wherein the LO derivation circuitry is configured to derive the cancellation TX LO signal from the RX LO signal. ### Claim 3 (depends on 1) The self-interference cancellation system of claim 1, wherein the cancellation TX LO signal is the common LO signal and wherein the LO derivation circuitry is configured to derive the RX LO signal from the cancellation TX LO signal. ### Claim 4 (depends on 1) The self-interference cancellation system of claim 1, wherein the common LO signal is different from the cancellation TX LO signal and the RX LO signal and wherein the LO derivation circuitry is configured to derive the cancellation TX LO signal from the common LO signal and to derive the RX LO signal from the common LO signal. ### Claim 5 (depends on 1) The self-interference cancellation system of claim 1, wherein the LO derivation circuitry comprises a digital-to-time converter configured to convert the common LO signal to a derived LO signal based on a duplex offset frequency. ### Claim 6 (depends on 1) The self-interference cancellation system of claim 1, wherein the LO derivation circuitry comprises a mixer configured to convert the common LO signal to a derived LO signal based on a duplex offset frequency. ### Claim 7 (depends on 1) The self-interference cancellation system of claim 1, further comprising phase-noise cancellation circuitry configured to cancel phase-noise mixing products from the baseband corrected received signal to generate a desired baseband received signal, the phase-noise cancellation circuitry comprising: an auxiliary LO generator configured to: extract a phase modulation of the baseband transmit leakage replica signal; and up-convert the extracted phase modulation to twice a duplex offset frequency to generate a phase modulated auxiliary LO signal; a mixer configured to down-convert the baseband received signal with the auxiliary LO signal to generate a down-converted baseband received signal; a conjugation circuitry configured to process the down-converted baseband received signal to generate a conjugate signal; and a second cancellation circuitry configured to combine the conjugate signal with the baseband received signal to generate the desired baseband received signal. ### Claim 8 A method to cancel self-interference in a transceiver, the method comprising: deriving a cancellation transmit (TX) local oscillator LO signal and a receive (RX) LO signal from a common LO signal; up-converting a baseband transmit leakage replica signal using the cancellation TX LO signal to generate a cancellation signal; combining the cancellation signal with a received signal to generate a corrected received signal; and down-converting the corrected received signal using the RX LO signal to generate a baseband corrected received signal. ### Claim 9 (depends on 8) The method of claim 8, comprising deriving the cancellation TX LO signal from the RX LO signal. ### Claim 10 (depends on 8) The method of claim 8, comprising deriving the RX LO signal from the cancellation TX LO signal. ### Claim 11 (depends on 8) The method of claim 8, wherein the common LO signal is different from the cancellation TX LO signal and the RX LO signal and wherein the method further comprises deriving the cancellation TX LO signal from the common LO signal and deriving the RX LO signal from the common LO signal. ### Claim 12 (depends on 8) The method of claim 8, further comprising deriving a derived LO signal from the common LO signal using a digital-to-time converter that inputs a ramp function having a slope approximately equal to a duplex offset frequency. ### Claim 13 (depends on 8) The method of claim 8, further comprising deriving a derived LO signal from the common LO signal using a mixer that shifts a frequency of the common LO signal by approximately a duplex offset frequency. ### Claim 14 (depends on 8) The method of claim 8, further comprising: extracting a phase modulation of the baseband transmit leakage replica signal; up-converting the extracted phase modulation to twice a duplex offset frequency to generate a phase modulated auxiliary LO signal; down-converting the baseband received signal with the auxiliary LO signal to generate a down-converted baseband received signal; processing the down-converted baseband received signal to generate a conjugate signal; and combining the conjugate signal with the baseband received signal to generate a desired baseband received signal. ### Claim 15 A transceiver, comprising: a transmit chain configured to generate a transmitted signal from a baseband transmitted signal; a receive chain configured to generate a desired baseband received signal from a received signal; and a self-interference cancellation system, comprising: a replica circuitry configured to generate a baseband transmit leakage replica signal from the baseband transmitted signal; a cancellation signal circuitry configured to use a cancellation transmit (TX) local oscillator (LO) signal to up-convert the baseband transmit leakage replica signal to generate a cancellation signal; a cancellation circuitry configured to combine the cancellation signal with the received signal to generate a corrected received signal wherein the receive chain comprises a down-conversion mixer configured to use a receive (RX) LO signal to down-convert the corrected received signal to generate a baseband corrected received signal; and an LO derivation circuitry configured to derive the cancellation TX LO signal and the RX LO signal from a common LO signal. ### Claim 16 (depends on 15) The transceiver of claim 15, wherein the RX LO signal is the common LO signal and wherein the LO derivation circuitry is configured to derive the cancellation TX LO signal from the RX LO signal. ### Claim 17 (depends on 15) The transceiver of claim 15, wherein the cancellation TX LO signal is the common LO signal and wherein the LO derivation circuitry is configured to derive the RX LO signal from the cancellation TX LO signal. ### Claim 18 (depends on 15) The transceiver of claim 15, wherein the common LO signal is different from the cancellation TX LO signal and the RX LO signal and wherein the LO derivation circuitry is configured to derive the cancellation TX LO signal from the common LO signal and to derive the RX LO signal from the common LO signal. ### Claim 19 (depends on 15) The transceiver of claim 15, wherein the LO derivation circuitry comprises a digital-to-time converter configured to convert the common LO signal to a derived LO signal based on a duplex offset frequency. ### Claim 20 (depends on 15) The transceiver of claim 15, wherein the LO derivation circuitry comprises a mixer configured to convert the common LO signal to a derived LO signal based on a duplex offset frequency. ### Claim 21 (depends on 15) The transceiver of claim 15, further comprising phase-noise cancellation circuitry configured to cancel phase-noise mixing products from the baseband received signal to generate a desired baseband received signal, the phase-noise cancellation circuitry comprising: an auxiliary LO generator configured to: extract a phase modulation of the baseband transmit leakage replica signal; and up-convert the extracted phase modulation to twice a duplex offset frequency to generate a phase modulated auxiliary LO signal; a mixer configured to down-convert the baseband received signal with the auxiliary LO signal to generate a down-converted baseband received signal; a conjugation circuitry configured to process the down-converted baseband received signal to generate a conjugate signal; and a second cancellation circuitry configured to combine the conjugate signal with the baseband received signal to generate the desired baseband received signal.