Abstract: Disclosed is a method performed by a receiver of a wireless communication network (100), for estimating antenna calibration error in the receiver based on one or more Reference Signals, RS, sent by one or more transmitters of the wireless communication network. The receiver comprises a plurality of radio antennas arranged in a known geometrical configuration. The method comprises obtaining (302) channel data of a communication channel between the transmitter and the receiver based on the one or more RS sent wirelessly between the transmitter and the plurality of antennas of the receiver, the obtained (302) channel data comprising HOTA and HRX. HOTA being the channel data contributed by a wireless propagation path between the transmitter and the receiver, HRX being the channel data contributed by the antenna calibration error of the receiver.

Abstract: A method of precoding matrix indicator, PMI, generation for channel state information, CSI, compression in a communication system comprising a first radio transceiver device, RTD, and a second RTD, the method comprising: transmitting, from the second RTD to the first RTD, a reference signal; receiving, at the first RTD from the second RTD, the reference signal; estimating, at the first RTD, CSI based on the received reference signal; generating, at the first RTD, a PMI to perform CSI compression, wherein the PMI indicates a precoding matrix, selected from among a codebook of precoding matrices, based on orthogonal matching pursuit, OMP, processing of the estimated CSI; generating, at the first RTD, a compressed CSI based on the generated PMI for transmission to the second RTD; and transmitting the compressed CSI from the first RTD to the second RTD.

Abstract: A computer-implemented method performed by a device configured with a power feature aided machine learning, ML, model is provided that models a behavior of a DPD to reduce non-linear distortion of an output signal of a non-linear device. The method includes extracting a plurality of power features from an input signal destined to be input to the DPD. The method further includes labelling the extracted plurality of power features to obtain at least one labelled average power level; inputting the at least one labelled average power level to the input of the ML model to obtain an output signal from the ML model having characteristics to reduce the non-linear distortion of the output signal of the non-linear device; and providing the output signal from the ML model as an input to the non-linear device.

Abstract: There is provided mechanisms for operating a DPD for a non-linear electronic device. A method is performed by a DPD controller. The method comprises receiving an input signal destined to be input to the non-linear electronic device. The method comprises selecting a basis function that represent non-linear input-output characteristics of the non-linear electronic device. The basis function is defined by kernels of a pruned Volterra series, and comprises higher-than-order-1 polynomial terms, polynomial cross-terms, memory cross-terms, and common tap delays shared by all polynomial terms. The method comprises obtaining an output signal by subjecting the input signal to a linearization function defined by the basis function. The method comprises providing the output signal as input to the non-linear electronic device.

Abstract: A method of precoding matrix indicator, PMI, generation for channel state information, CSI, compression in a first radio transceiver device, RTD the method comprising: receiving, from a second RTD, a reference signal; estimating CSI based on the received reference signal; generating a PMI to perform CSI compression, wherein the PMI indicates a precoding matrix, selected from among a codebook of precoding matrices, based on orthogonal matching pursuit, OMP, processing of the estimated CSI; and generating a compressed CSI based on the generated PMI for transmission to the second RTD.

Abstract: There is provided mechanisms for operating a digital pre-distorter for a non-linear electronic device. A method comprises receiving an input signal destined to be input to the non-linear electronic device. The method comprises selecting, for basis functions that represent input-output characteristics of the non-linear electronic device, a set of tap delays. The set of tap delays is selected using a block orthogonal matching pursuit algorithm. The method comprises obtaining an output signal by subjecting the input signal to a linearization function defined by the basis functions with the selected set of tap delays. The method comprises providing the output signal as input to the non-linear electronic device.

Abstract: The present disclosure provides a method of antenna calibration for a radio system comprising an antenna system comprising a plurality of antenna elements corresponding to a plurality of radio chains. The method comprising performing first level antenna calibrations at a first time interval and performing second level antenna calibrations in between the first level antenna calibrations at a second time interval, wherein the second level antenna calibrations are based on estimations, and length of the first time interval is of more than one length of second time intervals. The present disclosure also provides a corresponding device, computer programs, and computer-readable storage.

Abstract: A method for antenna calibration for an active antenna system is disclosed. According to an embodiment, test signals are generated for multiple antennas of the active antenna system. The test signals are transmitted via the multiple antennas. A first signal that results from the transmission of the test signals is received over the air. A second signal is received from a coupler network of the active antenna system. The coupler network is configured to generate coupled signals of the test signals and combine the coupled signals into the second signal. Calibration information for compensating an influence of the coupler network is determined based on the first and second signals. An active antenna system is also disclosed for use in antenna calibration.

Abstract: A method of calibrating an antenna array in a wireless network node is disclosed, the wireless network node including a plurality of antenna branches, each of the plurality of antenna branches including a respective antenna element. The method includes repeating operations of transmitting a slice of a fountain coded sequence through the plurality of antenna branches to the respective antenna elements, and for each antenna branch of the plurality of antenna branches, selecting the transmitted slice as a feedback signal through a return path and determining a signal quality of the feedback signal, until the signal quality of the feedback signal for each antenna branch is greater than a threshold level. The method further includes performing antenna calibration based on the feedback signal for each antenna branch. Related devices, computer programs and computer program products are disclosed.

Abstract: Embodiments of the present disclosure provide method and apparatus for antenna calibration. A method implemented at a first network device. The method includes receiving a first radio signal generated by the first network device via a receiver connected to an antenna of the first network device. The method further includes receiving at least one second radio signal from at least one second network device via the antenna of the first network device. The method further includes determining an impairment related to the antenna of the first network device based on the received first radio signal and the at least one second radio signal. There is a line of sight (LOS) path between the antenna of the first network device and the antenna of each of the at least one second network device.

Abstract: The present disclosure provides a method (400) for facilitating Antenna Calibration, AC. The method (400) includes: identifying (410) a leakage signal from a signal received at an AC signal receiver and resulted from a reference signal originated from an AC signal transmitter passing through an AC signal path from the AC signal transmitter to the AC signal receiver; and cancelling (420) an influence of the leakage signal on an AC process.

Abstract: It provides a method (300) for polar decoding a received signal into a number, N, of bits with Successive Cancellation List, SCL. The method (300) includes: at the i-th level of a binary tree for decoding the i-th bit of the N bits, where 1?i?N: when the i-th bit is an information bit, calculating (310) a path metric for each of 2*Li-1 candidate paths at the i-th level, where Li-1 is an SCL size at the (i?1)-th level and L0=1; setting (320) an SCL size at the i-th level, Li, based on Li-1 and a statistical distribution of the path metrics calculated for the 2*Li-1 candidate paths; and selecting (330) Li surviving paths from the 2*Li-1 candidate paths based on their respective path metrics.

Abstract: Embodiments of the present disclosure provide methods and apparatus for antenna calibration. A method implemented at a network function comprises calibrating an antenna of the network function based on available time-frequency resources. The method further comprises communicating with at least one terminal device via the calibrated antenna.

Abstract: Various embodiments of the present disclosure provide a method for multi-antenna transmission. The method which may be performed by a communication device comprises determining first correlation information in response to interference to data on a first subset of multiple antenna branches of the communication device. The first correlation information may indicate at least correlation between the data on the first subset of the multiple antenna branches and data on a second subset of the multiple antenna branches which is not affected by interference. The method further comprises correcting the data on the first subset of the multiple antenna branches, based at least in part on the first correlation information.

Abstract: Embodiments of the present disclosure provide methods and apparatus for antenna calibration. A method implemented at a network function comprises calibrating an antenna of the network function based on available time-frequency resources. The method further comprises communicating with at least one terminal device via the calibrated antenna.

Abstract: In one example aspect, a method is provided of preparing a symbol for transmission, the method comprising applying a window function to a symbol to generate a modified symbol, wherein a property of the window function is based on a channel length of a transmission channel over which the modified symbol is to be transmitted, and causing the modified symbol to be transmitted over the transmission channel.

Abstract: A method of calibrating an antenna array in a wireless network node is disclosed, the wireless network node including a plurality of antenna branches, each of the plurality of antenna branches including a respective antenna element. The method includes repeating operations of transmitting a slice of a fountain coded sequence through the plurality of antenna branches to the respective antenna elements, and for each antenna branch of the plurality of antenna branches, selecting the transmitted slice as a feedback signal through a return path and determining a signal quality of the feedback signal, until the signal quality of the feedback signal for each antenna branch is greater than a threshold level. The method further includes performing antenna calibration based on the feedback signal for each antenna branch. Related devices, computer programs and computer program products are disclosed.

Abstract: Various embodiments of the present disclosure provide a method for multi-antenna transmission. The method which may be performed by a communication device comprises determining first correlation information in response to interference to data on a first subset of multiple antenna branches of the communication device. The first correlation information may indicate at least correlation between the data on the first subset of the multiple antenna branches and data on a second subset of the multiple antenna branches which is not affected by interference. The method further comprises correcting the data on the first subset of the multiple antenna branches, based at least in part on the first correlation information.

Abstract: A method for antenna calibration for an active antenna system is disclosed. According to an embodiment, test signals are generated for multiple antennas of the active antenna system. The test signals are transmitted via the multiple antennas. A first signal that results from the transmission of the test signals is received over the air. A second signal is received from a coupler network of the active antenna system. The coupler network is configured to generate coupled signals of the test signals and combine the coupled signals into the second signal. Calibration information for compensating an influence of the coupler network is determined based on the first and second signals. An active antenna system is also disclosed for use in antenna calibration.

Abstract: A method for antenna calibration for an active antenna system is disclosed. According to an embodiment, test signals are generated for multiple antennas of the active antenna system. The test signals are transmitted via the multiple antennas. A first signal that results from the transmission of the test signals is received over the air. A second signal is received from a coupler network of the active antenna system. The coupler network is configured to generate coupled signals of the test signals and combine the coupled signals into the second signal. Calibration information for compensating an influence of the coupler network is determined based on the first and second signals. An active antenna system is also disclosed for use in antenna calibration.