In certain aspects, a device for wireless transmission includes a transmission path, a feedback path, and a DPD control module. The transmission path includes a digital pre-distortion (DPD) conversion module configured to perform pre-distortion processing on an amplitude and a phase of a transmission signal based on a pre-distortion processing strategy. The transmission path further includes a power amplifier coupled to a downstream of the DPD conversion module and configured to amplify a power of the transmission signal. The feedback path is coupled to the transmission path at the downstream of the power amplifier and configured to generate a feedback signal. The feedback path includes a static gain compensation module configured to be activated during an initial time period of each frame to track and update a static gain for the feedback signal and configured to hold the static gain after the initial time period of each frame. The DPD control module is coupled to the feedback path and the DPD conversion module and configured to adjust the pre-distortion processing strategy based on an amplitude difference and a phase difference between the transmission signal and the feedback signal.

A polar transmitter provided for transmitting a phase/frequency modulated and amplitude modulated transmit signal and a method for generating a transmit signal using a polar transmitter are described. An example polar transmitter comprises a phase locked loop for generating a phase/frequency modulated precursor of the transmit signal. The phase locked loop comprises at its input a phase error detection unit for detecting a phase error of the precursor fed back from the output of the phase locked loop to the phase error detection unit as a feedback signal. The polar transmitter comprises a digital amplitude modulator for amplitude modulation of the precursor, resulting in the transmit signal. The digital amplitude modulator is arranged within the phase locked loop for amplitude modulation of the precursor before being output by the PLL. The phase error detection unit is further provided for detecting the amplitude of the feedback signal.

Circuits, devices and methods related to antenna tuner. In some embodiments, an antenna can be tuned by amplifying a signal for transmission by operating a transistor with a base current, and monitoring the base current. The method can further include adjusting an antenna tuner to thereby adjust an antenna load impedance presented to the amplified signal, with the adjustment being based on a variation of the monitored base current.

A communication apparatus for a vehicle according to an embodiment and a control method therefor are disclosed. The communication apparatus for a vehicle comprises: an antenna unit including a first antenna and a plurality of second antennas; a first switch for switching a first path to the first antenna and a second path to each of the plurality of second antennas; a second switch for switching a second path to any one of the plurality of second antennas; a length adjustment unit that is connected to the second path to the one second antenna connected to the second switch and adjusts the resonance length of the connected second antenna; and a communication control unit that generates a switching signal for connection to any one of the plurality of second antennas according to the state of the first antenna.

Reconfigurable output baluns for wideband push-pull amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver that generates a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier that selectively amplifies one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an impedance of the output balun.

Within many applications impulse radio based ultra-wideband (IR-UWB) transmission offers significant benefits for very short range high data rate communications when compared with existing standards and protocols. In many of these applications the main design goals are very low power consumption and very low complexity design for easy integration and cost reduction. Digitally programmable IR-UWB transmitters using an on-off keying modulation scheme on a 0.13 microns CMOS process operating on 1.2V supply and yielding power consumption as low as 0.9 mW at a 10 Mbps data rate with dynamic power control are enabled. The IR-UWB transmitters support new frequency hopping techniques providing more efficient spectrum usage and dynamic allocation of the spectrum when transmitting in highly congested frequency bands. Biphasic scrambling is also introduced for spectral line reduction. Additionally, an energy detection receiver for IR-UWB is presented to similarly meet these design goals whilst being adaptable to address IR-UWB transmitter specificity.

A cross-division duplex (XDD) system includes an apparatus having a transceiver configured to communicate via an uplink channel and a downlink channel concurrently. The apparatus also includes a transmit antenna, a receive antenna, and a processor. The processor is configured to: estimate a non-linear component corresponding to a transmit path in the transceiver; apply an equalizer function to a received signal; and subtract, in a self-interference cancel (SIC) circuitry, the estimated non-linear component from the equalized signal.

A method and apparatus for cancelling local oscillator feedthrough (LOFT). A transmitter includes a first mixer configured to mix a transmit signal with a first local oscillator signal. An observation receiver receives a fraction of a power of the transmit signal as a feedback signal and processes the feedback signal. The observation receiver includes a second mixer configured to mix the feedback signal with a second local oscillator signal. A LOFT correction estimation circuitry is configured to determine a DC offset to cancel LOFT at the first mixer in the transmitter based on measurements on outputs of the second mixer. An LOFT correction circuitry is configured to add the DC offset to the transmit signal. The LOFT correction estimation circuitry may determine the DC offset based on several measurements obtained by varying the DC offset and a phase shift in the second local oscillator signal in the observation receiver.

An amplitude and phase control device includes a signal dividing unit to divide a transmission signal into first and second signals and output the first and second signals to a Doherty amplifier, an error calculating unit to acquire, from the Doherty amplifier, a synthesized signal of first and second signals amplified by the Doherty amplifier, multiply the synthesized signal by a reciprocal of a gain of the Doherty amplifier, and calculate an error between a synthesized signal after being multiplied by the reciprocal and the transmission signal, and a controlling unit to control an amplitude of each of the first signal and the second signal output from the signal dividing unit depending on the error calculated by the error calculating unit, and control a phase difference between the first signal output from the signal dividing unit and the second signal output from the signal dividing unit depending on the error.

A wireless device includes a distortion compensation unit that imparts a distortion compensation component to a radio signal and outputs the radio signal, an amplifier that amplifies the radio signal to which the distortion compensation component is imparted by the distortion compensation unit, and a signal-to-noise-ratio adjustment unit that deteriorates a signal to noise ratio of an output signal of the amplifier and outputs the output signal as a feedback signal, in which the distortion compensation unit estimates, from the feedback signal, a distortion component contained in the output signal of the amplifier and imparts the distortion compensation component having an inverse characteristic of the estimated distortion component to the radio signal.