This disclosure relates to a wideband extremely large array antenna system and an OFDM-based hybrid beamforming for hybrid-field interference control of the same. The wideband extremely large array antenna system for OFDM-based hybrid beamforming of this disclosure may include a transmitter having a plurality of transmit antennas, and a receiver capable of communication with the transmitter and having a plurality of receiving antennas, and the system may be configured to perform a first step for designing a common analog beamforming matrix for all subcarriers between the transmitter and the receiver, and a second step for designing a baseband beamforming matrix for each of the subcarriers.

Aspects of the present disclosure relate to utilizing an intelligent reflecting surface (IRS), a tracking algorithm, or both, to receive, calibrate, and maintain orbital angular momentum (OAM) signaling between wireless devices. The present disclosure describes a first wireless device transmitting spatial-multiple input-multiple output (MIMO) beams to the IRS such that reflected waves from the IRS form a spatial mixture of OAM modes. The IRS may reflect such OAM modes to a second wireless device for subsequent reflection (e.g., a second IRS), reception, calibration, and optimization. For example, the second wireless device may perform pattern recognition of the concentric OAM modes (e.g., by estimating ellipse geometry) to determine the modes of the OAM signaling. The second wireless device may also perform decorrelation, where small perturbations to the elliptical OAM geometry allow the second wireless device to perform one or more optimization techniques related to the OAM signaling.

According to an aspect, there is provided an apparatus for performing the following. The apparatus maintains, in at least one memory, information on a reference incidence direction and reference configuration information defining a plurality of configurations of a plurality of tunable load impedance circuits of a tunable reflective array of a reconfigurable intelligent surface or a subpanel thereof for the reference incidence direction. The apparatus measures an incidence direction from which electromagnetic waves are received by the reconfigurable intelligent surface. The apparatus calculates, based on the reference incidence direction, the measured incidence direction and the reference configuration information, corrected configuration information defining a plurality of corrected configurations for the measured incidence direction. Finally, the apparatus configures the plurality of tunable load impedance circuits according to a corrected configuration.

Methods, systems, and devices for wireless communications are described. Generally, a reconfigurable intelligent surface (RIS) may transmit a capability information message including an indicating that the RIS is capable of participating in network communications and communicating with other RISs on the network. A first RIS may communicate beam information to a second RIS directly, or the first RIS may communicate beam information to the second RIS via a base station, or the first RIS may communicate beam information to the second RIS via a user equipment (UE). In some examples, one RIS may request beam information or reflecting assistance from another RIS.

Disclosed are a method and an apparatus for codebook design in a communication system. A method of a base station may comprise: transmitting a pilot signal to a terminal by using a reconfigurable intelligent surface (RIS); receiving, from the terminal, channel information measured based on the pilot signal; estimating characteristics of elements of the RIS based on the channel information; generating a codebook based on the estimated characteristics of the elements; and transmitting the codebook to a controller of the RIS.

A reconfigurable intelligent surface (RIS) in a radio network includes a plurality of passive elements which are controlled by a plurality of active elements distributed among the plurality of passive elements, wherein the plurality of active elements configure the reconfigurable intelligent surface to perform, based on at least one request message, at least one of sensing incident electromagnetic radiation harvested over at least one frequency range by the passive elements; and steering energy of the harvested electromagnetic radiation towards at least one energy harvesting device in the radio network. A network node is configured to select at least one reconfigurable intelligent surface in a radio network; and send at least one request message to the selected reconfigurable intelligent surface to cause the reconfigurable intelligent surface to steer harvested electromagnetic radiation within at least one frequency range toward at least one energy harvesting device in the radio network.

The present disclosure provides a base station. The base station includes: a control unit configured to determine configuration information regarding a reconfigurable surface device based on location of a user equipment; and a transmitting unit configured to send the configuration information to the reconfigurable surface device so that the reconfigurable surface device determines a codebook used by the reconfigurable surface device based on the configuration information.

The disclosure relates to a 5.sup.th generation (5G) or 6.sup.th generation (6G) communication system for supporting higher data transmission rates than 4th generation (4G) communication systems, such as long-term evolution (LTE) systems. A method and a device are provided. The method includes, by a user equipment (UE) in a wireless communication system, receiving RIS information from an RIS controller (RC), identifying an incident beam incident on the UE, providing information about the identified incident beam to the RC and requesting information about candidate RIS modes, receiving the information about the candidate RIS modes, performing probing on the candidate RIS modes, deriving a final RIS mode among the candidate RIS modes using a result of the probing, and transmitting information about the final RIS mode to an RIS through the RC.

Methods, systems, and devices for wireless communications are described. Techniques described herein provide for a network entity to determine a beam focusing distance for a reconfigurable intelligent surface (RIS) for a user equipment (UE) located in the near field region of the RIS. The beam focusing distance may be determined using reference signals for different test beam focusing distances within the near field region of the RIS. The test beams may have a same angular direction from the RIS to the UE. The test beams may have a beam focusing distance selected from a set of beam focusing distances within the near field region of the RIS.

Certain aspects of the present disclosure provide techniques for a method for wireless communication by a first wireless entity, comprising: receiving signaling from a second network entity to configure reconfigurable intelligent surface (RIS) elements based on a direction of a target incident signal and a direction of a target reflected signal, and configuring the RIS elements based on the direction of the target incident signal and the direction of the target reflected signal and to randomize reflections, based on the signaling.