Systems and methods for duplexer circuits having signal cancellation paths are provided. In one aspect, a duplexer circuit includes a first transmit filter configured to receive a first radio frequency transmit signal from a power amplifier, and a first receive filter configured to receive the first radio frequency transmit signal from the first transmit filter. The circuit also includes a first low-noise amplifier configured to receive the first radio frequency transmit signal from the first receive filter and amplify the first radio frequency transmit signal and a cancellation path configured to receive a second radio frequency transmit signal from the power amplifier. The circuit further includes a phase shifter configured to apply a phase shift to one or both of the first and second radio frequency transmit signals, and a second low-noise amplifier configured to amplify the second radio frequency transmit signal.

The demodulating apparatus includes circuits of receiving modulated radio signals coming from a plurality of transmission devices, first demodulating a first reception signal DPSK-modulated among the radio signals, modulating demodulation signals into modulation signals based on DPSK, estimating an amplitude and a phase of a propagation signal on a propagation path leading to the reception circuit from the transmission device on the basis of the radio signal and the modulation signal, first generating, based on the variables, a first simulated signal simulating the first reception signal from the modulation signal, extracting a signal obtained by cancelling the first simulated signal from the radio signals, and repeating processes of the first demodulating, the modulating, the estimating, the first generating and the extracting to such a limit as to enable the first demodulating.

The demodulating apparatus includes circuits of receiving modulated radio signals coming from a plurality of transmission devices, first demodulating a first reception signal DPSK-modulated among the radio signals, modulating demodulation signals into modulation signals based on DPSK, estimating an amplitude and a phase of a propagation signal on a propagation path leading to the reception circuit from the transmission device on the basis of the radio signal and the modulation signal, first generating, based on the variables, a first simulated signal simulating the first reception signal from the modulation signal, extracting a signal obtained by cancelling the first simulated signal from the radio signals, and repeating processes of the first demodulating, the modulating, the estimating, the first generating and the extracting to such a limit as to enable the first demodulating.

A carrier aggregation method can include amplifying a first signal with a first current converter to generate a current representative of the amplified first signal, and amplifying a second signal with a second current converter to generate a current representative of the amplified second signal. The method can further include processing the amplified first signal and the amplified second signal with an adder circuit, with the first current converter and the adder circuit forming a first cascode amplifier, and the second current converter and the adder circuit forming a second cascode amplifier. The method can further include providing an output signal at a common output node that is coupled to an output of each of the first and second cascode amplifiers.

A received signal is enhanced by removing distortion components of a concurrently transmitted signal. A received signal is acquired in a receive frequency band concurrently with transmission of a transmit signal in a transmit frequency band. The received signal includes an intermodulation distortion component of the transmit signal. A representation of the transmit signal is processed using a non-linear predictor to output a distortion signal representing predicted distortion components in the received signal. The received signal is enhanced using the distortion signal by removing the predicted distortion components from the received signal corresponding to the distortion signal.

A received signal is enhanced by removing distortion components of a concurrently transmitted signal. A received signal is acquired in a receive frequency band concurrently with transmission of a transmit signal in a transmit frequency band. The received signal includes an intermodulation distortion component of the transmit signal. A representation of the transmit signal is processed using a non-linear predictor to output a distortion signal representing predicted distortion components in the received signal. The received signal is enhanced using the distortion signal by removing the predicted distortion components from the received signal corresponding to the distortion signal.

Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.

Systems, devices, methods, and computer-readable media for spread spectrum (SS) receiver interference mitigation are presented. An interference mitigation unit can include an interference analyzer that receives a complex-valued signal and estimates statistical characteristics of at least a portion of the complex-valued signal, a unit controller that receives the estimated statistical characteristics from the interference analyzer, classifies the interference distribution based on statistical characteristics as a Gaussian, long-tail, or short-tail, selects a non-linearity for that distribution, and a programmable non-linear module that performs a non-linear functional conversion of an envelope of the received complex-valued signal using a non-linear input-output characteristic based on the classification by the unit controller.

The demodulating apparatus includes circuits of receiving modulated radio signals coming from a plurality of transmission devices, first demodulating a first reception signal DPSK-modulated among the radio signals, modulating demodulation signals into modulation signals based on DPSK, estimating an amplitude and a phase of a propagation signal on a propagation path leading to the reception circuit from the transmission device on the basis of the radio signal and the modulation signal, first generating, based on the variables, a first simulated signal simulating the first reception signal from the modulation signal, extracting a signal obtained by cancelling the first simulated signal from the radio signals, and repeating processes of the first demodulating, the modulating, the estimating, the first generating and the extracting to such a limit as to enable the first demodulating.

The demodulating apparatus includes circuits of receiving modulated radio signals coming from a plurality of transmission devices, first demodulating a first reception signal DPSK-modulated among the radio signals, modulating demodulation signals into modulation signals based on DPSK, estimating an amplitude and a phase of a propagation signal on a propagation path leading to the reception circuit from the transmission device on the basis of the radio signal and the modulation signal, first generating, based on the variables, a first simulated signal simulating the first reception signal from the modulation signal, extracting a signal obtained by cancelling the first simulated signal from the radio signals, and repeating processes of the first demodulating, the modulating, the estimating, the first generating and the extracting to such a limit as to enable the first demodulating.