# US 11,451,363 B2 · Digital-centric full-duplex architecture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,363 B2 - Document ID: US11451363B2 - Status: Granted - Kind: B2 - Application number: 15/197,528 - Filed: 2016-06-29 - Published: 2018-01-04 - Granted: 2022-09-20 - Earliest claimed: 2016-06-29 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Bernhard Raaf - Web page: https://patentgrep.com/patent/US11451363B2 ## CPC - H04L 5/1461: {Suppression of signals in the return path, i.e. bidirectional control circuits} - H04B 1/123: {using adaptive balancing or compensation means (adaptive filter circuits and algorithms H03H)} - H04B 1/44: Transmit/receive switching - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract A full-duplex radio device is disclosed. The full-duplex radio device includes an analog transmission (TX) circuit that includes a power amplifier to output an analog TX signal. The full-duplex radio device also includes a feedback receiver circuit coupled to the analog TX circuit. The feedback receiver circuit provides a digital representation of the analog TX signal that is used to digitally cancel at least a transmitter noise component of a self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device. ## Claims ### Claim 1 A full-duplex radio device configured to cancel a self-interference signal in a digital domain, the full-duplex radio device comprising: a digital transmission circuit configured to output a digital transmission baseband signal; an analog transmission circuit coupled to the digital transmission circuit and configured to receive the digital transmission baseband signal and output an analog transmission signal; an analog receiver circuit configured to receive the self-interference signal via a circulator coupled between the analog transmission circuit and the analog receiver circuit, and wherein the analog receiver is configured to convert the self-interference signal from a carrier frequency to an analog representation of the self-interference signal in baseband; a feedback receiver circuit, coupled to the analog transmission circuit and configured to output a digital representation of the analog transmission signal; and a digital receiver circuit coupled to the digital transmission circuit, the analog receiver circuit, and the feedback receiver circuit, wherein the digital receiver circuit is configured to: convert the analog representation of the self-interference signal in baseband received from the analog receiver circuit to a digital representation of the self-interference signal in baseband; and combine the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device. ### Claim 2 (depends on 1) The full-duplex radio device of claim 1, wherein the full-duplex radio device is an in-band full-duplex device configured to concurrently transmit and receive signals in a same frequency band. ### Claim 3 (depends on 1) The full-duplex radio device of claim 1, wherein the feedback receiver circuit is further configured to: tap the analog transmission circuit to receive a copy of the analog transmission signal; and convert the copy of the analog transmission signal to the digital representation of the analog transmission signal. ### Claim 4 (depends on 1) The full-duplex radio device of claim 1, wherein the analog transmission circuit comprises: a digital to analog converter configured to receive the digital transmission baseband signal and convert the digital transmission baseband signal to an analog signal; an upconverter coupled to the digital to analog converter and configured to upconvert the analog signal outputted by the digital to analog converter; and a power amplifier coupled to the upconverter and configured to receive the upconverted analog signal outputted by the upconverter and amplify the upconverted analog signal to generate the analog transmission signal. ### Claim 5 (depends on 1) The full-duplex radio device of claim 1, wherein the feedback receiver circuit comprises: a downconverter configured to receive the analog transmission signal and down convert the analog transmission signal; and an analog to digital converter configured to convert the down converted analog transmission signal to the digital transmission signal. ### Claim 6 (depends on 1) The full-duplex radio device of claim 1, wherein the analog receiver circuit comprises: a low noise amplifier configured to receive the self interference signal and output an amplified signal; and a down converter configured to receive the amplified signal and down convert the amplified signal to the analog representation of the self-interference signal in baseband. ### Claim 7 (depends on 1) The full-duplex radio device of claim 1, wherein the circulator is configured to attenuate the analog transmission signal to generate the self-interference signal. ### Claim 8 (depends on 1) The full-duplex radio device of claim 1, wherein the digital transmission signal includes a linear noise component, a non-linear noise component, and a transmitter noise component. ### Claim 9 (depends on 1) The full-duplex radio device of claim 1, wherein the digital receiver circuit comprises a summation circuit, wherein, to combine the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device, the summation circuit is configured to: use the digital transmission signal to cancel at least a transmitter noise component of digital representation of the self-interference signal in baseband. ### Claim 10 (depends on 1) The full-duplex radio device of claim 1, wherein the digital receiver circuit comprises a summation circuit, wherein, to combine the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device, the summation circuit is configured to: use the digital transmission signal to cancel noise components that are from leakage of the circulator and echoes of the analog transmission signal. ### Claim 11 (depends on 10) The full-duplex radio device of claim 10, wherein the echoes of the analog transmission signal are part of self-interference signal or are external echoes that stem from reflections after the circulator. ### Claim 12 (depends on 11) The full-duplex radio device of claim 11, wherein the echoes are delayed and phase shifted. ### Claim 13 A method for a full-duplex radio device, comprising: providing, to a digital receiver circuit, a digital transmission baseband signal via a digital transmission circuit, an analog transmission signal via an analog transmission circuit, an analog representation of a self-interference signal in baseband via an analog receiver circuit, and a digital representation of the analog transmission signal via a feedback receiver circuit; converting the analog representation of the self-interference signal in baseband received provided via the analog receiver circuit to a digital representation of the self-interference signal in baseband; and combining the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device. ### Claim 14 (depends on 13) The method of claim 13, wherein combining combine the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device comprises using the digital transmission signal to cancel at least a transmitter noise component of digital representation of the self-interference signal in baseband. ### Claim 15 (depends on 13) The method of claim 13, wherein combining combine the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device comprises using the digital transmission signal to cancel noise components that are from leakage of a circulator and echoes of the analog transmission signal. ### Claim 16 (depends on 15) The method of claim 15, wherein the echoes of the analog transmission signal are part of self-interference signal or are external echoes that stem from reflections after the circulator. ### Claim 17 (depends on 16) The method of claim 16, wherein the echoes are delayed and phase shifted. ### Claim 18 A user equipment device (UE), comprising: a digital transmission circuit configured to output a digital transmission baseband signal; an analog transmission circuit coupled to the digital transmission circuit and configured to receive the digital transmission baseband signal and output an analog transmission signal; an analog receiver circuit configured to receive the self-interference signal via a circulator coupled between the analog transmission circuit and the analog receiver circuit, and wherein the analog receiver is configured to convert the self-interference signal from a carrier frequency to an analog representation of the self-interference signal in baseband; a feedback receiver circuit, coupled to the analog transmission circuit and configured to output a digital representation of the analog transmission signal; and a digital receiver circuit coupled to the digital transmission circuit, the analog receiver circuit, and the feedback receiver circuit, wherein the digital receiver circuit is configured to: convert the analog representation of the self-interference signal in baseband received from the analog receiver circuit to a digital representation of the self-interference signal in baseband; and combine the digital representation of the self-interference signal in baseband, the digital representation of the analog transmission signal received from the feedback receiver circuit, and the digital transmission baseband signal received from the digital transmission circuit to cancel at least a transmitter noise component of the self-interference signal associated with a transmission of the analog TX signal in the full-duplex radio device. ### Claim 19 (depends on 18) The UE of claim 18, wherein the full-duplex radio device is an in-band full-duplex device configured to concurrently transmit and receive signals in a same frequency band. ### Claim 20 (depends on 18) The UE of claim 18, wherein the feedback receiver circuit is further configured to: tap the analog transmission circuit to receive a copy of the analog transmission signal; and convert the copy of the analog transmission signal to the digital representation of the analog transmission signal. ### Claim 21 (depends on 18) The UE of claim 18, wherein the analog transmission circuit comprises: a digital to analog converter configured to receive the digital transmission baseband signal and convert the digital transmission baseband signal to an analog signal; an upconverter coupled to the digital to analog converter and configured to upconvert the analog signal outputted by the digital to analog converter; and a power amplifier coupled to the upconverter and configured to receive the upconverted analog signal outputted by the upconverter and amplify the upconverted analog signal to generate the analog transmission signal. ### Claim 22 (depends on 18) The UE of claim 18, wherein the feedback receiver circuit comprises: a downconverter configured to receive the analog transmission signal and down convert the analog transmission signal; and an analog to digital converter configured to convert the down converted analog transmission signal to the digital transmission signal.