Aspects of this disclosure relate to a time-division duplex (TDD) multiple-input multiple-output (MIMO) system that includes a plurality of nodes. The plurality of nodes collectively includes antennas divided into groups. Reference signals can be transmitted from each group of antennas to one or more other groups of antennas during respective time slots. Channel estimates can be generated based on the received reference signals. The channel estimates can be jointly processed to generate calibration coefficients. Each calibration coefficient can represent a ratio associated with a transmit coefficient and a receive coefficient. Example algorithms for the joint processing are disclosed.

A method at a UE for responding to a change in physical state of the UE includes: determining that a physical relationship between a first antenna element of the UE and another component of the UE has changed from a first state; and providing at least one notification in response to determining that the physical relationship between the first antenna element and the other component of the has changed from the first state.

There is provided mechanisms for calibrating transmit antenna chains and receive antenna chains of an antenna system. A method is performed by a network node. The method comprises obtaining a set of observations from bi-directional sounding of pairs of antennas of the antenna system. Each of the antennas has one transmit antenna chain and one receive antenna chain. The observations are represented by a composite product of transmit calibration weights, receive calibration weights, and signal leakage terms. The method comprises estimating the transmit calibration weights and the receive calibration weights from a decomposition of the composite product. The method comprises calibrating the transmit antenna chains and the receive antenna chains by applying as calibration factors the estimated transmit calibration weights to the transmit antenna chains and the receive calibration weights to the receive antenna chains.

In accordance with a first aspect of the present disclosure, a near field communication (NFC) device is provided, comprising: an NFC transceiver configured to communicate with an external NFC device and to apply at least one transceiver parameter when communicating with the external NFC device; a calibration unit operatively coupled to the NFC transceiver and configured to calibrate the NFC transceiver; wherein the calibration unit is configured to calibrate the NFC transceiver by causing the NFC transceiver to apply different values of the transceiver parameter, measuring a noise level in the NFC transceiver for each applied value of the transceiver parameter, and selecting an optimal value from the applied values of the transceiver parameter in dependence on the noise level measured for each applied value. In accordance with a second aspect of the present disclosure, a corresponding method of operating an NFC device is conceived.

A computer implemented method for self-calibration of a Phased Array Antenna (PAA) having an array of N antenna elements. Each element operates as a transmit antenna element and/or as a receive antenna element. The method includes building an overdetermined system of linear equations presenting different couples of antenna elements. Each equation expressing a difference between a value of a real parameter, determined for a specific couple, and a sum of unknowns including unknown calibrated parameters of the antenna elements forming the specific couple, Next, solving the system of equations for obtaining a solution in the form of values of corrections to be applied to corresponding antenna elements in the array, in order to reduce the difference in each of the equations by bringing internal parameters of the antenna elements in a specific couple closer to their respective unknown calibrated parameters. Each couple being formed from a transmit antenna element and a receive antenna element positioned at an arbitrary distance from one another in the PAA array.

A system can comprise a radio unit comprising a digital front end, wherein the digital front end comprises a group of tap points that are configured to receive a first custom signal. The system can also comprise a first component that is configured to originate the first custom signal. The system can also comprise a second component that is configured to select a first tap point of the group of tap points, and inject the first custom signal into the first tap point.

Aspects of this disclosure relate to a time-division duplex (TDD) multiple-input multiple-output (MIMO) system that includes a plurality of nodes. The plurality of nodes collectively includes antennas divided into groups. Reference signals can be transmitted from each group of antennas to one or more other groups of antennas during respective time slots. Channel estimates can be generated based on the received reference signals. The channel estimates can be jointly processed to generate calibration coefficients. Each calibration coefficient can represent a ratio associated with a transmit coefficient and a receive coefficient. Example algorithms for the joint processing are disclosed.

A first wireless device and a second device may negotiate a configuration of an RF chain calibration process with each other. The configuration of the RF chain calibration process may include a number of calibration rounds. The second wireless device may exchange, in each calibration round in the number of calibration rounds, at least one RS and at least one feedback message with the first wireless device. The second wireless device may identify one or more calibration adjustment parameters for the second wireless device based on the RF chain calibration process. The second wireless device may communicate with another wireless device based on the one or more calibration adjustment parameters.

A system can comprise a radio unit comprising a digital front end, wherein the digital front end comprises a group of tap points that are configured to receive a first custom signal. The system can also comprise a first component that is configured to originate the first custom signal. The system can also comprise a second component that is configured to select a first tap point of the group of tap points, and inject the first custom signal into the first tap point.

Beamforming is a critical element of 5G and especially 6G, but currently requires a series of time-consuming and resource-consuming messages. Disclosed are procedures by which base stations can transmit a phased beam pulse, having a phase that varies with angle, so that each user device can measure the received phase of the pulse and thereby determine its angle relative to the base station. Each user can then sequentially inform the base station of its orientation relative to the base station, or can append that information to another message such as an initial access message or an acknowledgement, for example. The user device and the base station can then exchange messages in narrow beams aimed at each other according to the alignment angle. Also disclosed are procedures to economically generate the wide-angle phased beam by combining overlapping beams of various phases.