# US 7,613,260 B2 · Modem control using cross-polarization interference estimation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,260 B2 - Document ID: US7613260B2 - Status: Granted - Kind: B2 - Application number: 11/285,414 - Filed: 2005-11-21 - Published: 2007-05-24 - Granted: 2009-11-03 - Earliest claimed: 2005-11-21 - Assignees: Provigent Ltd. - Inventors: Amir Eliaz; Avi Turgeman; Ahikam Aharony; Jonathan Friedmann - Web page: https://patentgrep.com/patent/US7613260B2 ## CPC - H04L 25/03057: {with a recursive structure (H04L25/03031 takes precedence)} - H04B 7/10: Polarisation diversity; Directional diversity - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract A receiver includes an input circuit, which is coupled to at least one antenna so as to receive, process and digitize first and second signals, thus generating first and second streams of input samples. An interference cancellation circuit in the receiver includes first and second adaptive filters, which are respectively coupled to filter the first and second streams of input samples using respective first and second coefficients to generate respective first and second filter outputs. A phase rotator is adapted to apply a variable phase shift compensating for a phase deviation between the first and second signals, the phase rotator having at least one configuration parameter. A control module is operative to estimate signal characteristics of the interference cancellation circuit and to set the at least one configuration parameter of the phase rotator responsively to the estimated signal characteristics. ## Claims ### Claim 1 A receiver, comprising: an input circuit, which is coupled to at least one antenna so as to receive, process and digitize first and second signals, thus generating first and second streams of input samples; and an interference cancellation circuit, comprising: first and second adaptive filters, which are respectively coupled to filter the first and second streams of input samples using respective first and second coefficients to generate respective first and second filter outputs; a phase rotator, which is adapted to apply a variable phase shift between the first and second signals, the phase rotator having at least one configuration parameter; and a control module, which is operative to compute the variable phase shift and to provide the variable phase shift to the phase rotator so as to compensate for a phase deviation between the first and second signals, to estimate interference in the first signal due to the second signal, and to set the at least one configuration parameter of the phase rotator responsively to the estimated interference. ### Claim 2 (depends on 1) The receiver according to claim 1, wherein the interference cancellation circuit is operative to produce responsively to the first and second streams of input samples a third stream of output samples representative of the first signal and having a reduced level of the interference. ### Claim 3 (depends on 2) The receiver according to claim 2, wherein the control module is operative to identify an increase of a level of the interference and to set the at least one configuration parameter responsively to the identified increase. ### Claim 4 (depends on 3) The receiver according to claim 3, wherein the phase rotator comprises a phase-locked loop (PLL), wherein the at least one configuration parameter comprises a frequency setting of the PLL, and wherein the control module is operative, subsequent to identifying the increase of the level of the interference, to search over a predefined range of frequency settings for a best frequency setting determined responsively to the estimated interference, and to load the best frequency setting to the PLL. ### Claim 5 (depends on 1) The receiver according to claim 1, wherein the first and second signals are transmitted with respective first and second, mutually orthogonal polarizations, and wherein the interference cancellation circuit is operative to reduce cross-polarization interference coupled from the second signal to the first signal. ### Claim 6 (depends on 1) The receiver according to claim 1, wherein the phase rotator comprises a phase-locked loop (PLL) and wherein the at least one configuration parameter comprises at least one of a loop bandwidth and a loop gain of the PLL. ### Claim 7 (depends on 1) The receiver according to claim 1, wherein the control module is operative to calculate the variable phase shift using at least one of a pilot-based and a batch-based phase estimation method. ### Claim 8 (depends on 1) The receiver according to claim 1, wherein the interference comprises a level of a crosscoupling between the first and second signals. ### Claim 9 (depends on 8) The receiver according to claim 8, wherein the first and second coefficients are determined adaptively in response to conditions on a communication channel over which the first and second signals are received, and wherein the control module is operative to estimate the level of the crosscoupling by performing a calculation based on at least some of the first and second coefficients. ### Claim 10 (depends on 1) The receiver according to claim 1, wherein the control module is operative to store two or more predefined control sets of the at least one configuration parameter, to evaluate a metric function responsively to the estimated interference, to choose a selected control set out of the two or more predefined control sets responsively to the evaluated metric function, and to load the chosen control set into the phase rotator. ### Claim 11 (depends on 1) The receiver according to claim 1, wherein the control module is operative to adaptively calculate the at least one configuration parameter responsively to the estimated interference. ### Claim 12 (depends on 1) The receiver according to claim 1, wherein the second signal contains distortion due to the first signal, and wherein the interference cancellation circuit is further operative to produce responsively to the first and second streams of input samples a fourth stream of output samples representative of the second signal and having a reduced level of the distortion. ### Claim 13 A wireless communication system, comprising: a transmitter, which is operative to transmit first and second signals over the air; and a receiver, which comprises: an input circuit, which is coupled to at least one antenna so as to receive, process and digitize the first and second signals, thus generating first and second streams of input samples; and an interference cancellation circuit, comprising: first and second adaptive filters, which are respectively coupled to filter the first and second streams of input samples using respective first and second coefficients to generate respective first and second filter outputs; a phase rotator, which is adapted to apply a variable phase shift between the first and second signals, the phase rotator having at least one configuration parameter; and a control module, which is operative to compute the variable phase shift and to provide the variable phase shift to the phase rotator so as to compensate for a phase deviation between the first and second signals, to estimate interference in the first signal due to the second signal, and to set the at least one configuration parameter of the phase rotator responsively to the estimated interference. ### Claim 14 (depends on 13) The system according to claim 13, wherein the interference cancellation circuit is operative to produce responsively to the first and second streams of input samples a third stream of output samples representative of the first signal and having a reduced level of the interference. ### Claim 15 (depends on 14) The system according to claim 14, wherein the control module is operative to identify an increase of a level of the interference and to set the at least one configuration parameter responsively to the identified increase. ### Claim 16 (depends on 15) The system according to claim 15, wherein the phase rotator comprises a phase-locked loop (PLL), wherein the at least one configuration parameter comprises a frequency setting of the PLL, and wherein the control module is operative, subsequent to identifying the increase of the level of the interference, to search over a predefined range of frequency settings for a best frequency setting determined responsively to the estimated interference, and to load the best frequency setting to the PLL. ### Claim 17 (depends on 13) The system according to claim 13, wherein the first and second signals are transmitted with respective first and second, mutually orthogonal polarizations, and wherein the interference cancellation circuit is operative to reduce cross-polarization interference coupled from the second signal to the first signal. ### Claim 18 (depends on 13) The system according to claim 13, wherein the phase rotator comprises a phase-locked loop (PLL) and wherein the at least one configuration parameter comprises at least one of a loop bandwidth and a loop gain of the PLL. ### Claim 19 (depends on 13) The system according to claim 13, wherein the control module is operative to calculate the variable phase shift using at least one of a pilot-based and a batchbased phase estimation method. ### Claim 20 (depends on 13) The system according to claim 13, wherein the interference comprises a level of a cross-coupling between the first and second signals. ### Claim 21 (depends on 20) The system according to claim 20, wherein the first and second coefficients are determined adaptively in response to conditions on a communication channel over which the first and second signals are received, and wherein the control module is operative to estimate the level of the cross-coupling by performing a calculation based on at least some of the first and second coefficients. ### Claim 22 (depends on 13) The system according to claim 13, wherein the control module is operative to store two or more predefined control sets of the at least one configuration parameter, to evaluate a metric function responsively to the estimated interference, to choose a selected control set out of the two or more predefined control sets responsively to the evaluated metric function, and to load the chosen control set into the phase rotator. ### Claim 23 (depends on 13) The system according to claim 13, wherein the control module is operative to adaptively calculate the at least one configuration parameter responsively to the estimated interference. ### Claim 24 (depends on 13) The system according to claim 13, wherein the second signal contains distortion due to the first signal, and wherein the interference cancellation circuit is further operative to produce responsively to the first and second streams of input samples a fourth stream of output samples representative of the second signal and having a reduced level of the distortion. ### Claim 25 An interference cancellation circuit for processing first and second streams of input samples representing respective first and second signals, the circuit comprising: first and second adaptive filters, which are respectively coupled to filter the first and second streams of input samples using respective first and second coefficients to generate respective first and second filter outputs; a phase rotator, which is adapted to apply a variable phase shift between the first and second signals, the phase rotator having at least one configuration parameter; and a control module, which is operative to compute the variable phase shift and to provide the variable phase shift to the phase rotator so as to compensate for a phase deviation between the first and second signals, to estimate interference in the first signal due to the second signal, and to set the at least one configuration parameter of the phase rotator responsively to the estimated interference. ### Claim 26 (depends on 25) The circuit according to claim 25, wherein the circuit is operative to produce responsively to the first and second streams of input samples a third stream of output samples representative of the first signal and having a reduced level of the interference. ### Claim 27 (depends on 26) The circuit according to claim 26, wherein the control module is operative to identify an increase of a level of the interference and to set the at least one configuration parameter responsively to the identified increase. ### Claim 28 (depends on 27) The circuit according to claim 27, wherein the phase rotator comprises a phase-locked loop (PLL), wherein the at least one configuration parameter comprises a frequency setting of the PLL, and wherein the control module is operative, subsequent to identifying the increase of the level of the interference, to search over a predefined range of frequency settings for a best frequency setting determined responsively to the estimated interference, and to load the best frequency setting to the PLL. ### Claim 29 (depends on 25) The circuit according to claim 25, wherein the first and second signals are transmitted with respective first and second, mutually orthogonal polarizations, and wherein the circuit is operative to reduce cross-polarization interference coupled from the second signal to the first signal. ### Claim 30 (depends on 25) The circuit according to claim 25, wherein the phase rotator comprises a phase-locked loop (PLL) and wherein the at least one configuration parameter comprises at least one of a loop bandwidth and a loop gain of the PLL. ### Claim 31 (depends on 25) The circuit according to claim 25, wherein the control module is operative to calculate the variable phase shift using at least one of a pilot-based and a batch-based phase estimation method. ### Claim 32 (depends on 25) The circuit according to claim 25, wherein the interference comprises a level of a cross-coupling between the first and second signals. ### Claim 33 (depends on 32) The circuit according to claim 32, wherein the first and second coefficients are determined adaptively in response to conditions on a communication channel over which the first and second signals are received, and wherein the control module is operative to estimate the level of the crosscoupling by performing a calculation based on at least some of the first and second coefficients. ### Claim 34 (depends on 25) The circuit according to claim 25, wherein the control module is operative to store two or more predefined control sets of the at least one configuration parameter, to evaluate a metric function responsively to the estimated interference, to choose a selected control set out of the two or more predefined control sets responsively to the evaluated metric function, and to load the chosen control set into the phase rotator. ### Claim 35 (depends on 25) The circuit according to claim 25, wherein the control module is operative to adaptively calculate the at least one configuration parameter responsively to the estimated interference. ### Claim 36 (depends on 25) The circuit according to claim 25, wherein the second signal contains distortion due to the first signal, and wherein the circuit is further operative to produce responsively to the first and second streams of input samples a fourth stream of output samples representative of the second signal and having a reduced level of the distortion. ### Claim 37 A method for wireless communications, comprising: receiving, processing and digitizing first and second signals transmitted over the air so as to generate first and second streams of input samples; filtering the first and second streams of input samples using respective first and second coefficients to generate respective first and second filtered outputs; applying a variable phase shift to one of the first and second filtered outputs using a phase rotator having at least one configuration parameter so as to generate a phase-shifted output compensating for a phase deviation between the first and second signals; summing the first and second filtered outputs so as to generate a third stream of output samples, which is representative of the first signal; estimating interference in the first signal due to the second signal; and setting the at least one configuration parameter of the phase rotator responsively to the estimated interference. ### Claim 38 (depends on 37) The method according to claim 37, wherein summing the first and second filtered outputs comprises reducing the interference due to the second signal in the third stream of output samples. ### Claim 39 (depends on 38) The method according to claim 38, wherein setting the at least one configuration parameter comprises identifying an increase of a level of the interference, and setting the at least one configuration parameter responsively to the identified increase. ### Claim 40 (depends on 39) The method according to claim 39, wherein the phase rotator comprises a phase-locked loop (PLL), wherein the at least one configuration parameter comprises a frequency setting of the PLL, and wherein setting the at least one configuration parameter comprises, subsequent to identifying the increase of the level of the interference, searching over a predefined range of frequency settings for a best frequency setting determined responsively to the estimated interference, and loading the best frequency setting to the PLL. ### Claim 41 (depends on 37) The method according to claim 37, wherein receiving the first and second signals comprises receiving the signals transmitted with respective first and second, mutually orthogonal polarizations, and wherein summing the first filtered output with the phase-shifted output comprises reducing cross-polarization interference coupled from the second signal to the first signal. ### Claim 42 (depends on 37) The method according to claim 37, wherein the phase rotator comprises a phase-locked loop (PLL) and wherein setting the at least one configuration parameter comprises setting at least one of a loop bandwidth and a loop gain of the PLL. ### Claim 43 (depends on 37) The method according to claim 37, wherein applying the variable phase shift comprises calculating the variable phase shift using at least one of a pilot based and a batch-based phase estimation method. ### Claim 44 (depends on 37) The method according to claim 37, wherein estimating the interference comprises estimating a level of a cross-coupling between the first and second signals. ### Claim 45 (depends on 44) The method according to claim 44, wherein the first and second coefficients are determined adaptively in response to conditions on a communication channel over which the first and second signals are received, and wherein estimating the level of the cross-coupling comprises performing a calculation based on at least some of the first and second coefficients. ### Claim 46 (depends on 37) The method according to claim 37, wherein setting the at least one configuration parameter comprises: storing two or more predefined control sets of the at least one configuration parameter; evaluating a metric function responsively to the estimated interference; choosing a selected control set out of the two or more predefined control sets responsively to the evaluated metric function; and loading the chosen control set into the phase rotator. ### Claim 47 (depends on 37) The method according to claim 37, wherein setting the at least one configuration parameter comprises adaptively calculating the at least one configuration parameter responsively to the estimated interference.