A radio-frequency circuit includes a filter and a band elimination filter. The filter has a pass band corresponding to a first sub-band. At least part of the first sub-band is included in a first band used for TDD communication. The band elimination filter is connected to the filter and has a first elimination band which corresponds to a second sub-band included in the first band. The second sub-band is located between a third sub-band and a fourth sub-band. The third and fourth sub-bands are included in the first band. The first sub-band includes the second, third, and fourth sub-bands.

Techniques, described herein, include solutions for enabling power control processes within a wireless telecommunications network. A base station may operate in a full duplex mode by simultaneously sending and receiving signals to user equipment (UEs). Power control processes may be implemented to eliminate or mitigate signal interference, such as self-interference at the base station or cross link interference (CLI) at a UE. The power control processes may include causing UEs to transmit signals, a UE and/or the base station measuring interference and causing the base station and/or UEs to modify transmission power to address the signal interference.

Front end architectures are described that tailor duplexer characteristics to enable the removal of many of the impedance matching components typically included in a receive signal path between an antenna and receive amplifiers and in a transmit signal path between transmit amplifiers and the antenna. By tailoring duplexer characteristics, targeted impedance matching can be achieved for front end architectures. This enables the front-end architecture to impedance match without including typical impedance matching components along a signal path between the antenna and an amplifier. This can be implemented on the transmit signal path (e.g., between a power amplifier (PA) and the antenna), on the receive signal path (e.g., between the antenna and a low noise amplifier (LNA)), or both the transmit signal path and the receive signal path. Thus, the disclosed front end architectures are configured to reduce or eliminate the number of components required for impedance matching.

Examples described herein include systems and methods which include wireless devices and systems with examples of full duplex compensation with a self-interference noise calculator that compensates for the self-interference noise generated by power amplifiers at harmonic frequencies of a respective wireless receiver. The self-interference noise calculator may be coupled to antennas of a wireless device and configured to generate the adjusted signals that compensate self-interference. The self-interference noise calculator may include a network of processing elements configured to combine transmission signals into sets of intermediate results. Each set of intermediate results may be summed in the self-interference noise calculator to generate a corresponding adjusted signal. The adjusted signal is receivable by a corresponding wireless receiver to compensate for the self-interference noise generated by a wireless transmitter transmitting on the same or different frequency band as the wireless receiver is receiving.

Examples described herein include systems and methods which include wireless devices and systems with examples of full duplex compensation with a self-interference noise calculator that compensates for the self-interference noise generated by power amplifiers at harmonic frequencies of a respective wireless receiver. The self-interference noise calculator may be coupled to antennas of a wireless device and configured to generate the adjusted signals that compensate self-interference. The self-interference noise calculator may include a network of processing elements configured to combine transmission signals into sets of intermediate results. Each set of intermediate results may be summed in the self-interference noise calculator to generate a corresponding adjusted signal. The adjusted signal is receivable by a corresponding wireless receiver to compensate for the self-interference noise generated by a wireless transmitter transmitting on the same or different frequency band as the wireless receiver is receiving.

An efficiently-transformed digital self-interference canceller, preferably including an FD transformer, a TD transformer, a channel estimator, a composer, and a controller. The canceller can optionally include a channel memory, a predictor, and/or an extender. A method for digital self-interference cancelation, preferably including receiving inputs, transforming the inputs, generating outputs based on the transformed inputs, transforming the outputs, and/or generating a cancellation signal based on the outputs.

An efficiently-transformed digital self-interference canceller, preferably including an FD transformer, a TD transformer, a channel estimator, a composer, and a controller. The canceller can optionally include a channel memory, a predictor, and/or an extender. A method for digital self-interference cancelation, preferably including receiving inputs, transforming the inputs, generating outputs based on the transformed inputs, transforming the outputs, and/or generating a cancellation signal based on the outputs.

A cascade comprising multiple filters according to an embodiment comprises a filter, which includes a splitter configured to split an analog radio-frequency input signal into at least a first signal and a second signal, a first signal path configured to generate, based on the first signal, a time-delayed signal delayed by a predetermined delay time in the time domain, a second signal path configured to generate, based on the second signal, a phase-shifted signal shifted by a controllable predetermined phase shift in the phase domain, and a coupler configured to generate an output signal based on the time-delayed signal and the phase-shifted signal. Using an embodiment may improve a trade-off between frequency-related flexibility and frequency agility of a receiver infrastructure.

A cascade comprising multiple filters according to an embodiment comprises a filter, which includes a splitter configured to split an analog radio-frequency input signal into at least a first signal and a second signal, a first signal path configured to generate, based on the first signal, a time-delayed signal delayed by a predetermined delay time in the time domain, a second signal path configured to generate, based on the second signal, a phase-shifted signal shifted by a controllable predetermined phase shift in the phase domain, and a coupler configured to generate an output signal based on the time-delayed signal and the phase-shifted signal. Using an embodiment may improve a trade-off between frequency-related flexibility and frequency agility of a receiver infrastructure.

A system for enhancing isolation in coexisting time-division duplexed (TDD) transceivers includes: a blocker canceller that transforms a transmit signal of a TDD transceiver into a blocker cancellation signal configured to remove transmit-band interference in a receive signal; a first filter that filters the blocker cancellation signal; a second filter that filters the transmit signal; and a transmit-noise canceller that transforms the filtered transmit signal into a transmit noise cancellation signal configured to remove receive-band interference in the receive signal.