A mechanism for identifying a low performing radio branch at a radio transceiver device. A method is performed by the radio transceiver device that comprises transmitting a reference signal for at least some of the N radio branches in a respective test period. The reference signal in each test period is transmitted according to a test configuration that specifies that during each test period the reference signal is mapped to only one of the N radio branches such that in test period k, where k=1, . . . , N, the reference signal is only transmitted from radio branch k. The method comprises receiving at least one report from another radio transceiver device relating to measurements made by this so-called another radio transceiver device on the reference signal transmitted for these at least some of the N radio branches to identify which of the N radio branches is the low performing one.

A mechanism for identifying a low performing radio branch at a radio transceiver device. A method is performed by the radio transceiver device that comprises transmitting a reference signal for at least some of the N radio branches in a respective test period. The reference signal in each test period is transmitted according to a test configuration that specifies that during each test period the reference signal is mapped to only one of the N radio branches such that in test period k, where k=1, . . . , N, the reference signal is only transmitted from radio branch k. The method comprises receiving at least one report from another radio transceiver device relating to measurements made by this so-called another radio transceiver device on the reference signal transmitted for these at least some of the N radio branches to identify which of the N radio branches is the low performing one.

Provided is a method performed by a user equipment (UE) in a wireless communication system. The method includes performing communication with a base station based on a full-duplex mode, transmitting, to the base station, a first message for requesting a duration for calibration of a circuit for analog self-interference cancellation (SIC), receiving, from the base station, a second message for allocating the duration, and performing the calibration of the circuit during the duration. Herein, during the duration, the UE is controlled to operate based on a half-duplex mode.

A method and apparatus for (a) operating a first full-duplex transceiver to exchange radio-frequency signals with a second full-duplex transceiver, (b) determining at the first full-duplex transceiver that a residual self-interference signal exceeds a threshold, (c) in response to the determination that the residual self-interference signal exceeds the threshold, performing a self-training operation.

A method and apparatus for (a) operating a first full-duplex transceiver to exchange radio-frequency signals with a second full-duplex transceiver, (b) determining at the first full-duplex transceiver that a residual self-interference signal exceeds a threshold, (c) in response to the determination that the residual self-interference signal exceeds the threshold, performing a self-training operation.

A calibration circuit 2 according to the present disclosure is a calibration circuit 2 in a radio base station system 1 including a remote unit part 10 and a plurality of distributed antenna parts 20 connected to the remote unit part 10 through a plurality of respective cables, the calibration circuit 2 including: a detection unit 2a configured to detect a plurality of local oscillation signals that are output from a local oscillator 13 of the remote unit part 10 and are respectively reflected from the plurality of distributed antenna parts 20 through the plurality of cables; and a phase adjustment unit 2b configured to adjust a phase of each of the plurality of local oscillation signals output through the plurality of respective cables from the remote unit part 10 based on a result of the detection.

Embodiments of apparatus and method for generating waveforms for self-testing of radio frequency (RF) chips are disclosed. In an example, an RF chip includes an RF front-end and a digital front-end. The digital front-end includes an inverse fast Fourier transform (IFFT) module configured to generate at least one M-point IFFT sample, where M is a positive integer, and an IFFT sample transformation module configured to generate an L-point IFFT testing signal based on the at least one M-point IFFT sample. L is a positive integer greater than M and the L-point IFFT testing signal is configured to test a function of the RF chip.

Embodiments of apparatus and method for generating waveforms for self-testing of radio frequency (RF) chips are disclosed. In an example, an RF chip includes an RF front-end and a digital front-end. The digital front-end includes an inverse fast Fourier transform (IFFT) module configured to generate at least one M-point IFFT sample, where M is a positive integer, and an IFFT sample transformation module configured to generate an L-point IFFT testing signal based on the at least one M-point IFFT sample. L is a positive integer greater than M and the L-point IFFT testing signal is configured to test a function of the RF chip.

A user equipment (UE) may simulate transmissions received from a BS to perform on-device testing of the UE. For example, the UE may be configured to loopback uplink data from the UL data path and input the uplink data as simulated downlink data for processing in the DL data path. The uplink data may include data related to a video call or network diagnostics. The user application data generated by the application and proceeding through the UL data path may be used to validate the DL data path. Downlink control information (DCI) may be determined by the UE and provided to the DL data path to accompany the uplink data. The DCI may include simulated uplink grants and/or simulated downlink scheduling assignments. The simulated downlink scheduling assignments may be determined based on availability of the uplink data in the UE's memory.

Methods and systems for automated testing of extremely-high frequency devices are disclosed. A device under test (DUT) is set in a simultaneous transmit and receive mode. The DUT receives a lower frequency radio frequency (RF) signal from a test unit and up-converts the lower frequency RF signal to a higher frequency RF signal. The DUT transmits the higher frequency RF signal using a first antenna, and receives the higher frequency RF signal using a second antenna. The DUT down-converts the received higher frequency RF signal to a received test RF signal and provides the received test RF signal to the test unit for comparing measurements derived from the received test signal to a design specification for the DUT.