Disclosed is a multi-band transmitter for transmitting a multi-band signal. The multi-band transmitter comprises: a pre-distortion unit including a first digital pre-distorter (DPD) which pre-distorts a first band signal and a second DPD which pre-distorts a second band signal discontinuous from the first band signal; a conversion unit which analog-converts the pre-distorted first band signal and the pre-distorted second band signal; an amplification unit including a first power amplifier (PA), which amplifies the analog-converted first band signal, and a second PA, which amplifies the analog-converted second band signal; and a feedback unit which digital-converts the amplified first band signal to feed the digital-converted first band signal back to the first DPD and digital-converts the amplified second band signal to feed the digital-converted second band signal back to the second DPD. The pre-distortion unit performs pre-distortion by using the fed-back first band signal and the fed-back second band signal.

Systems, devices, and methods related to hybrid basis function, neural network-based digital predistortion (DPD) are provided. An example apparatus for a radio frequency (RF) transceiver includes a digital predistortion (DPD) actuator to receive an input signal associated with a nonlinear component of the RF transceiver and output a predistorted signal. The DPD actuator includes a basis-function-based actuator to perform a first DPD operation using a set of basis functions associated with a first nonlinear characteristic of the nonlinear component. The DPD actuator further includes a neural network-based actuator to perform a second DPD operation using a first neural network associated with a second nonlinear characteristic of the nonlinear component. The predistorted signal is based on a first output signal of the basis-function-based actuator and a second output signal of the neural network-based actuator.

Certain aspects of the present disclosure provide techniques for training a digital pre-distorter (DPD) using real-time over-the-air transmissions and receptions by a user equipment (UE). A method for training the DPD generally includes transmitting a signal, generated by a transmitter front end, via a first port; sampling the signal, received over the air, at a second port; performing signal processing cleaning (e.g., synchronization, linear over-the-air channel estimation and equalization); calculating coefficients for a DPD; and configuring the DPD with the coefficients, for use in digitally pre-distorting sub sequent transmissions.

Certain aspects of the present disclosure provide techniques for training a digital pre-distorter (DPD) using real-time over-the-air transmissions and receptions by a user equipment (UE). A method for training the DPD generally includes transmitting a signal, generated by a transmitter front end, via a first port; sampling the signal, received over the air, at a second port; performing signal processing cleaning (e.g., synchronization, linear over-the-air channel estimation and equalization); calculating coefficients for a DPD; and configuring the DPD with the coefficients, for use in digitally pre-distorting sub sequent transmissions.

When signals are simultaneously received from K transmission-side apparatuses by a receiving antenna, and repetition is performed by the K transmission-side apparatuses, an information processing apparatus is configured to: in order to obtain a transmitted reference signal x(k,n) transmitted from a transmission-side apparatus k (k=1, . . . , K) by the n-th reference signal transmission in the repetition, acquire a phase rotation amount φ(g,n) given to a transmitted reference signal x(k) and assigned to a group g to which the transmission-side apparatus k belongs and transmit the phase rotation amount φ(g,n) to the transmission-side apparatus k. The phase rotation amount φ(g,n) is acquired so that received reference signals from transmission-side apparatuses not belonging to the group g are cancelled when a phase rotation amount opposite to the phase rotation amount φ(g,n) is given to a received reference signal r(n), and the first to N-th received reference signals in the repetition are added.

When signals are simultaneously received from K transmission-side apparatuses by a receiving antenna, and repetition is performed by the K transmission-side apparatuses, an information processing apparatus is configured to: in order to obtain a transmitted reference signal x(k,n) transmitted from a transmission-side apparatus k (k=1, . . . , K) by the n-th reference signal transmission in the repetition, acquire a phase rotation amount φ(g,n) given to a transmitted reference signal x(k) and assigned to a group g to which the transmission-side apparatus k belongs and transmit the phase rotation amount φ(g,n) to the transmission-side apparatus k. The phase rotation amount φ(g,n) is acquired so that received reference signals from transmission-side apparatuses not belonging to the group g are cancelled when a phase rotation amount opposite to the phase rotation amount φ(g,n) is given to a received reference signal r(n), and the first to N-th received reference signals in the repetition are added.

An apparatus is disclosed for transmission setting selection. In an example aspect, an apparatus includes a wireless interface device with a communication processor and a radio-frequency front-end. The communication processor is configured to provide a signal. The radio-frequency front-end is coupled to the communication processor and configured to accept the signal. The radio-frequency front-end includes an amplifier configured to amplify the signal based on one or more amplifier settings. The wireless interface device is configured to adjust the one or more amplifier settings responsive to an output power being changed with a gain being unchanged.

An apparatus is disclosed for transmission setting selection. In an example aspect, an apparatus includes a wireless interface device with a communication processor and a radio-frequency front-end. The communication processor is configured to provide a signal. The radio-frequency front-end is coupled to the communication processor and configured to accept the signal. The radio-frequency front-end includes an amplifier configured to amplify the signal based on one or more amplifier settings. The wireless interface device is configured to adjust the one or more amplifier settings responsive to an output power being changed with a gain being unchanged.

A digital radio frequency (RF) transmitter including processing circuitry configured to generate first through third pattern signals based on a pattern of an inphase (I)-quadrature (Q) binary data pair and a pattern of an inverted I-Q binary data pair, the first through third pattern signals having a same pattern and different phases, and a switched-capacitor digital-to-analog converter (SC-DAC) configured to remove an n-th harmonic component of an RF analog signal by amplifying the first through third pattern signals to have a certain magnitude ratio and synthesizing the amplified first through third pattern signals into the RF analog signal, where “n” is an integer of at least 3, may be provided.

A digital radio frequency (RF) transmitter including processing circuitry configured to generate first through third pattern signals based on a pattern of an inphase (I)-quadrature (Q) binary data pair and a pattern of an inverted I-Q binary data pair, the first through third pattern signals having a same pattern and different phases, and a switched-capacitor digital-to-analog converter (SC-DAC) configured to remove an n-th harmonic component of an RF analog signal by amplifying the first through third pattern signals to have a certain magnitude ratio and synthesizing the amplified first through third pattern signals into the RF analog signal, where “n” is an integer of at least 3, may be provided.