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.

Systems and associated methods for reciprocity calibration of multiple-input multiple-output (MIMO) wireless communication are disclosed herein. In one embodiment, a method for reciprocity calibration of the MIMO system includes transmitting a pilot symbol by a transmitter (TX) of the reference antenna and receiving the pilot symbol by receivers (RXes) of antennas of a base station as r.sub.i,0 pilot symbols. (Index “i” denotes individual antenna “i” of the base station, and “0” denotes the reference antenna.) The method further includes transmitting the received pilot symbols by TXes of the antennas of the base station, receiving the pilot symbols transmitted by the antennas of the base station by the reference antenna as r.sub.0,i pilot symbols, and calculating non-reciprocity compensation factors as

[00001]$\frac{r_{i,0}}{r_{0,i}}.$

An electronic device may include a harmonic rejection mixer with a delay line, mixer array, and load. The delay line may generate LO phases. Each mixer in the array may have a first input that receives an LO phase and a second input coupled to an input switch and the first input of the next mixer circuit through an inter-mixer switch. The load may include a set of switches. In a transmit mode, the input switches and set of switches may be closed while the inter-mixer switches are open. In a self-calibration mode, the input switches and set of switches may be open while the inter-mixer switches are closed. A controller may sweep through phase codes for the programmable delay line while storing a digital output from the load. The controller may calibrate the phase code based on the digital output.

In an embodiment, an apparatus includes a transmit section including a first baseband section and a first radio frequency (RF) section, wherein the transmit section is configured to receive a calibration signal, the first RF section is configured to generate a RF calibration signal based on modulating the calibration signal. The calibration signal comprises an orthogonal code based signal; and a receive section configured to receive the RF calibration signal over-the-air, the receive section includes a second RF section and a calibration section, the second RF section is configured to generate a received calibration signal based on the RF calibration signal, the received calibration signal and a reference signal associated with the RF calibration signal comprise inputs to the calibration section and the calibration section is configured to determine one or more of gain, baseband delay, or RF delay compensation values, based on the inputs, to calibrate the transmit section.

In an embodiment, an apparatus includes a transmit section including a first baseband section and a first radio frequency (RF) section, wherein the transmit section is configured to receive a calibration signal, the first RF section is configured to generate a RF calibration signal based on modulating the calibration signal. The calibration signal comprises an orthogonal code based signal; and a receive section configured to receive the RF calibration signal over-the-air, the receive section includes a second RF section and a calibration section, the second RF section is configured to generate a received calibration signal based on the RF calibration signal, the received calibration signal and a reference signal associated with the RF calibration signal comprise inputs to the calibration section and the calibration section is configured to determine one or more of gain, baseband delay, or RF delay compensation values, based on the inputs, to calibrate the transmit section.

In an embodiment, a communications system includes a first transmitter including a digital beamforming baseband section configured to receive an input signal to be transmitted, the input signal at a baseband frequency, and a modulation section electrically coupled to the digital beamforming baseband section and a first antenna of a phased array antenna. The modulation section is configured to receive a local oscillator signal at a first local oscillator frequency and apply a baseband frequency shift to the input signal to generate a baseband frequency shifted input signal. The modulation section generates a modulated signal based on the input signal. The communication system includes a second transmitter included in a second IC chip of the plurality of IC chips electrically coupled to a second antenna and configured to provide a second modulated signal at the carrier frequency and a second LO leakage signal at a second local oscillator frequency.

In an embodiment, a communications system includes a first transmitter including a digital beamforming baseband section configured to receive an input signal to be transmitted, the input signal at a baseband frequency, and a modulation section electrically coupled to the digital beamforming baseband section and a first antenna of a phased array antenna. The modulation section is configured to receive a local oscillator signal at a first local oscillator frequency and apply a baseband frequency shift to the input signal to generate a baseband frequency shifted input signal. The modulation section generates a modulated signal based on the input signal. The communication system includes a second transmitter included in a second IC chip of the plurality of IC chips electrically coupled to a second antenna and configured to provide a second modulated signal at the carrier frequency and a second LO leakage signal at a second local oscillator frequency.

A method of beamforming calibration is disclosed for a multi-antenna transceiver configured to communicate with one or more other transceivers. The multi-antenna transceiver has a plurality of transceiver chains connectable to respective antenna elements of the multi-antenna transceiver. Each transceiver chain comprises a transmitter path and a receiver path. The method comprises (for each transceiver chain) feeding an analog signal from the transmitter path to the receiver path via connection circuitry between the transmitter path and the receiver path to provide a digital calibration signal, and determining a beamforming calibration factor for the transceiver chain based on the digital calibration signal. Corresponding apparatus, multi-antenna transceiver, wireless communication node, and computer program product are also disclosed.

An electronic device may include at least one communication processor, at least one radio frequency integrated circuit (RFIC) configured to provide a radio frequency (RF) signal based on a signal from the at least one communication processor, and a first RF circuit and a second RF circuit configured to process and provide the RF signal. The at least one communication processor may be configured to control at least part of the electronic device to allow the first RF circuit to process at least one first RF signal provided from the RFIC, in an over-temperature state, identify that a sum of times when the first RF circuit processes the at least one first RF signal is at least the value of a designated period, and based on the sum of the times when the first RF circuit processes the at least one first RF signal being at least the value of the designated period, stop use of the first RF circuit and control at least part of the electronic device to allow the second RF circuit to process at least one second RF signal provided from the RFIC. Other various embodiments are possible as well.

An electronic device may include at least one communication processor, at least one radio frequency integrated circuit (RFIC) configured to provide a radio frequency (RF) signal based on a signal from the at least one communication processor, and a first RF circuit and a second RF circuit configured to process and provide the RF signal. The at least one communication processor may be configured to control at least part of the electronic device to allow the first RF circuit to process at least one first RF signal provided from the RFIC, in an over-temperature state, identify that a sum of times when the first RF circuit processes the at least one first RF signal is at least the value of a designated period, and based on the sum of the times when the first RF circuit processes the at least one first RF signal being at least the value of the designated period, stop use of the first RF circuit and control at least part of the electronic device to allow the second RF circuit to process at least one second RF signal provided from the RFIC. Other various embodiments are possible as well.