Abstract: System and method embodiments are provided for analog cancellation for division free duplexing for radios using MIMO. In an embodiment, a system for minimizing transmitted signals from a transmitter appearing at a co-located receiver in a division free duplexing radio includes a transmitter to transmit an analog transmitted signal; an antenna; a circulator coupled to the transmitter and the antenna; a tuning algorithm component configured to receive a copy of the analog transmitted signal from the transmitter and a sampled analog received signal from a received signal path from the circulator, wherein the sampled analog received signal is sampled at a point in the received signal path before the analog received signal is provided to a receiver; and a multitap cancellation component configured to provide a cancellation signal to couple to the analog received signal such that an amount of the analog transmitted signal appearing at the receiver is reduced.

Abstract: Same-channel full-duplex communications can be adapted for multiple-input multiple-output (MIMO) processing in order to derive increased signal performance through the exploitation of spatial diversity. Strong interference components from transmissions over multiple local antennas can be removed from a received radio signal to allow array and diversity gain benefits of MIMO to be enjoyed in same-channel full-duplex communications. More specifically, baseband samples of two or more MIMO transmission signals may be used to perform channel estimation on a received radio signal by correlating the baseband signals with the radio signal to estimate interference channels associated with the MIMO transmission signals. The estimated interference channels are used to subtract corresponding interference components from the received radio signals.

Abstract: Same-channel full-duplex communications can be adapted for multiple-input multiple-output (MIMO) processing in order to derive increased signal performance through the exploitation of spatial diversity. Strong interference components from transmissions over multiple local antennas can be removed from a received radio signal to allow array and diversity gain benefits of MIMO to be enjoyed in same-channel full-duplex communications. More specifically, baseband samples of two or more MIMO transmission signals may be used to perform channel estimation on a received radio signal by correlating the baseband signals with the radio signal to estimate interference channels associated with the MIMO transmission signals. The estimated interference channels are used to subtract corresponding interference components from the received radio signals.

Abstract: Embodiments are provided for cancelling self-interference in a full-duplex communications system. The cancellation includes using a digital cancellation stage in additional to analog cancellation. In an embodiment, a method by a full-duplex communications device includes sampling a received signal, wherein the sampling provides a received digital signal corresponding to the received signal. The method further includes sampling a transmitted signal, wherein the sampling provides a transmitted digital signal corresponding to the transmitted signal. A channel distortion introducing self-interference in the received signal is then estimated according to the transmitted digital signal and the received digital signal. The method further includes estimating the self-interference in the received digital signal according to the estimated channel distortion.

Abstract: In one embodiment, a method for calibrating a full-duplex radio system includes transmitting, by a first radio transmitter, a first signal and receiving, by a first radio receiver, a first version of the first signal. The method also includes receiving, by a second radio receiver, a second version of the first signal and transmitting, by a second radio transmitter, a second signal. Additionally, the method includes receiving, by the first radio receiver, a received version of the second signal and determining a response from the second radio transmitter to the first radio receiver in accordance with the first version of the first signal, the second version of the first signal, and the received version of the second signal.

Abstract: In one embodiment, a method for determining self-interference in radio full duplex includes transmitting, by a first radio transmitter and an antenna, a first signal and receiving, by a first radio receiver and the antenna, a reflection of the first signal. The method also includes estimating a channel in accordance with the first signal and the reflection of the first signal to produce an estimated channel and determining a second signal in accordance with the estimated channel. Additionally, the method includes transmitting, by a second radio transmitter, the second signal and removing a self-interference component of the reflection of the first signal to produce a corrected signal.

Abstract: Disclosed herein are an analog compensation circuit and a method for tuning an analog compensator in full-duplex transmission systems. An embodiment analog compensation circuit includes a secondary receiver configured to receive and convert a sampled self-interference signal to a baseband self-interference signal. A tuner is coupled to the secondary receiver and configured to receive a baseband transmit signal and the baseband self-interference signal, and to compute complex gains according to the baseband transmit signal and the baseband self-interference signal. An analog compensator is coupled to the tuner and has multiple branches. The analog compensator is configured to receive the complex gains and use them to adjust respective attenuators and phase shifters of the branches. The analog compensator is further configured to process a sample of a transmit signal using the branches, the transmit signal being up-converted from a new baseband transmit signal.

Abstract: System and method embodiments are provided for analog cancellation for division free duplexing for radios using MIMO. In an embodiment, a system for minimizing transmitted signals from a transmitter appearing at a co-located receiver in a division free duplexing radio includes a transmitter to transmit an analog transmitted signal; an antenna; a circulator coupled to the transmitter and the antenna; a tuning algorithm component configured to receive a copy of the analog transmitted signal from the transmitter and a sampled analog received signal from a received signal path from the circulator, wherein the sampled analog received signal is sampled at a point in the received signal path before the analog received signal is provided to a receiver; and a multitap cancellation component configured to provide a cancellation signal to couple to the analog received signal such that an amount of the analog transmitted signal appearing at the receiver is reduced.

Abstract: Disclosed herein are an analog compensation circuit and a method for tuning an analog compensator in full-duplex transmission systems. An embodiment analog compensation circuit includes a secondary receiver configured to receive and convert a sampled self-interference signal to a baseband self-interference signal. A tuner is coupled to the secondary receiver and configured to receive a baseband transmit signal and the baseband self-interference signal, and to compute complex gains according to the baseband transmit signal and the baseband self-interference signal. An analog compensator is coupled to the tuner and has multiple branches. The analog compensator is configured to receive the complex gains and use them to adjust respective attenuators and phase shifters of the branches. The analog compensator is further configured to process a sample of a transmit signal using the branches, the transmit signal being up-converted from a new baseband transmit signal.

Abstract: Embodiments are provided for cancelling self-interference in a full-duplex communications system. The cancellation includes using a digital cancellation stage in additional to analog cancellation. In an embodiment, a method by a full-duplex communications device includes sampling a received signal, wherein the sampling provides a received digital signal corresponding to the received signal. The method further includes sampling a transmitted signal, wherein the sampling provides a transmitted digital signal corresponding to the transmitted signal. A channel distortion introducing self-interference in the received signal is then estimated according to the transmitted digital signal and the received digital signal. The method further includes estimating the self-interference in the received digital signal according to the estimated channel distortion.

Abstract: In one embodiment, a method for calibrating a full-duplex radio system includes transmitting, by a first radio transmitter, a first signal and receiving, by a first radio receiver, a first version of the first signal. The method also includes receiving, by a second radio receiver, a second version of the first signal and transmitting, by a second radio transmitter, a second signal. Additionally, the method includes receiving, by the first radio receiver, a received version of the second signal and determining a response from the second radio transmitter to the first radio receiver in accordance with the first version of the first signal, the second version of the first signal, and the received version of the second signal.

Abstract: Same-channel full-duplex communications can be adapted for multiple-input multiple-output (MIMO) processing in order to derive increased signal performance through the exploitation of spatial diversity. Strong interference components from transmissions over multiple local antennas can be removed from a received radio signal to allow array and diversity gain benefits of MIMO to be enjoyed in same-channel full-duplex communications. More specifically, baseband samples of two or more MIMO transmission signals may be used to perform channel estimation on a received radio signal by correlating the baseband signals with the radio signal to estimate interference channels associated with the MIMO transmission signals. The estimated interference channels are used to subtract corresponding interference components from the received radio signals.

Abstract: In one embodiment, a method for determining self-interference in radio full duplex includes transmitting, by a first radio transmitter and an antenna, a first signal and receiving, by a first radio receiver and the antenna, a reflection of the first signal. The method also includes estimating a channel in accordance with the first signal and the reflection of the first signal to produce an estimated channel and determining a second signal in accordance with the estimated channel. Additionally, the method includes transmitting, by a second radio transmitter, the second signal and removing a self-interference component of the reflection of the first signal to produce a corrected signal.

Abstract: Disclosed herein are an analog compensation circuit and a method for tuning an analog compensator in full-duplex transmission systems. An embodiment analog compensation circuit includes a secondary receiver configured to receive and convert a sampled self-interference signal to a baseband self-interference signal. A tuner is coupled to the secondary receiver and configured to receive a baseband transmit signal and the baseband self-interference signal, and to compute complex gains according to the baseband transmit signal and the baseband self-interference signal. An analog compensator is coupled to the tuner and has multiple branches. The analog compensator is configured to receive the complex gains and use them to adjust respective attenuators and phase shifters of the branches. The analog compensator is further configured to process a sample of a transmit signal using the branches, the transmit signal being up-converted from a new baseband transmit signal.

Abstract: A spectrum sensor detects the presence of incumbent signals in the television-band. The spectrum sensor can detect digital Advanced Television Systems Committee (ATSC) signals below a ?114 dBm signal level and wireless microphone signals below a ?110 dBm signal level with false detection rates less than 10%. A radio module receives radio-frequency signals and produces an intermediate-frequency signal reflecting signal received in a selected television channel. A baseband processor module receives the intermediate-frequency signal, digitizes it, and processes the digital data to detecting whether an incumbent signal is present in the selected channel. The processing may include using pilot detection based on power spectrum thresholding or statistic characteristic extraction to detect ATSC signals. The processing may also include using power spectrum thresholding or covariance based signal detection to detect wireless microphone signals.

Abstract: The present invention comprises systems, methods, and devices for detecting the presence of a specified signal type by autocorrelating the signal with a time-delayed copy of itself, by simultaneously crosscorrelating the signal with an expected signal type, and by then comparing the results of the autocorrelation and crosscorrelation to determine whether or not the signal is present and to ascertain its type.

Abstract: The present invention comprises systems, methods, and devices for detecting the presence of a specified signal type by autocorrelating the signal with a time-delayed copy of itself, by simultaneously crosscorrelating the signal with an expected signal type, and by then comparing the results of the autocorrelation and crosscorrelation to determine whether or not the signal is present and to ascertain its type.