There is provided a reconfigurable intelligent surface. The reconfigurable intelligent surface includes antenna elements provided in a reflective array. Each antenna element has a controllable reflection phase. Only a strict subset of the antenna elements is arranged for obtaining radio measurements. The antenna elements of the strict subset are distributed across the reflective array. The reconfigurable intelligent surface includes a controller. The controller is configured to evaluate radio signal characteristics of the reflective array from the radio measurements. The controller is configured to control the reflection phases of the antenna elements as a function of the evaluated radio signal characteristics.

Various examples of the disclosure pertain to multi-device transmission via a coverage enhancing device such as a reconfigurable reflective device. Spatial filters are used at the coverage enhancing device that support a count of input spatial directions that is different than a count of output spatial directions.

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.

A method for wireless communication performed by a user equipment (UE) includes receiving multiple reference signals (RSs), each RS of the plurality of RSs being associated with a reflection from a respective reconfigurable intelligent surface (RIS), of multiple RISs, or with a direct transmission from a base station. The method also includes receiving, from the base station, a RIS configuration indicating a set of operative RISs, of the plurality of RISs, that reflect an uplink transmission from the UE. The method further includes transmitting, to the base station, an uplink message according to an uplink transmission power, the uplink transmission power being based on an effective pathloss that is a function of each pathloss of a set of pathlosses respectively associated with a set of RSs, of the multiple RSs, that are respectively associated with the set of operative RISs or the base station.

A radio channel may comprise a first component between two devices, and second and third components via the controllable scatterer. First reference signal(s) may be transmitted with the controllable scatterer configured to alter a propagation of signals such that influence of the second and third components of the radio channel is mitigated. Second reference signal(s) may be transmitted with the controllable scatterer configured to alter a propagation of signals such that influence of the second and third components of the radio channel is increased. An estimate of the first component may be determined based on the first reference signal(s) and an estimate of the third component may be determined based on the second reference signal(s) and a pre-computed estimate of the second component.