A method for sending a signal, performed by a reconfigurable intelligent surface (RIS) array, includes: determining a mapping relationship between an active RIS array element in the RIS array and a time-frequency resource; sending the mapping relationship to a user equipment (UE); and sending a pilot signal to the UE by mapping the pilot signal sent by the active RIS array element to the time-frequency resource corresponding to the active RIS array element.

Methods, systems, and devices for wireless communications are described. A reconfigurable intelligent surface (RIS) may indicate an ability to maintain phase continuity across transmissions. The RIS may transmit a capability information message and receive control signaling indicating one or more conditions under which the RIS may maintain phase continuity. For example, the RIS may maintain phase continuity when the separation time between consecutive transmissions may be long enough for the RIS to change to an original configuration or original set of transmission parameters. In other cases, the RIS may maintain phase continuity when the same configuration or set of transmission parameters are used between consecutive transmissions, and the time between the transmissions does not exceed a threshold. The RIS may relay signals based on the one or more conditions.

A method for the joint active and passive beamforming and received signal optimization in an ISAC system assisted by dual IRSs is provided. The method jointly optimizes active beamforming at Base Station (BS), reception of sensing signals at the Base Station (BS), and passive beamforming at IRSs, so as to maximize communication sum-rate of users while ensuring that SNR of sensing signals meets a minimum requirement. To address the complex non-convex optimization problem, the method first applies fractional programming to decouple problem, then adopts successive convex approximation algorithm and alternating direction method of multipliers to transform intractable non-convex problem into multiple tractable subproblems, and finally employs an alternating optimization method to efficiently acquire the high-quality suboptimal solutions. The simulation results demonstrate that disclosed scheme exhibits satisfactory convergence and effectiveness, and can significantly improve the performance of IRS-assisted ISAC systems.

A reconfigurable intelligent surface (RIS) antenna includes an RIS antenna body and a bias circuit. The RIS antenna body includes a plurality of RIS antenna units. The bias circuit is electrically coupled to the RIS antenna units of the RIS antenna body. Each RIS antenna unit includes: a metal pattern, a dielectric substrate and a control unit. The metal pattern and the control unit are formed on the dielectric substrate. The metal pattern has a resonance frequency. The control unit includes at least one metal oxide resistive element. The control unit is electrically coupled to the metal pattern and the bias circuit for changing the resonance frequency of the metal pattern by adjusting a bias applied by the bias circuit.

The technology described herein is directed towards a metasurface (reconfigurable intelligent surface) that can be used to redirect signals to and from non-terrestrial network satellites. The metasurface can be passive, and provide signal array gain with respect to indoor user equipment sending and receiving signals to and from the network satellites. The metasurface can be portable for use in various scenarios. Further, the metasurface can be configured to operate in a transmission mode, in which incoming signal is passed through the metasurface, or can be reconfigured to operate in a reflection mode, in which incoming signal is reflected by the metasurface. Different phase shifts of the metasurface's unit cells result in array gain through constructive interference, by refraction in the transmission mode, or reflection in the reflection mode. The presence or absence of a removable back plane determines the transmission or reflection operating mode of the metasurface.

Systems, methods, apparatuses, and computer program products for mode switching schemes for reconfigurable intelligent surface (RIS) assisted backscatter communications. The method may include connecting with a network node for communication, receiving, from the network node, an indication of activation of backscattering, receiving a backscatter signal together with a signal sent by the network node, and demodulating the backscatter signal and the signal sent by the network node, the backscatter signal including backscatter data.

A method of wireless communication at a user equipment (UE) is provided. The method includes receiving, from a scheduling entity, an indication of at least two different cross link interference (CLI) measurement resources of a message for transmission from a transmission source. The method also includes receiving, from an intelligent reflecting surface (IRS), a reflected transmission of the message originating from the transmission source, wherein the reflected transmission of the message is reflected by the IRS based on one or more IRS coefficients. The method further includes determining one or more CLI measurement parameters to generate a report. The method includes transmitting, to the scheduling entity, a CLI measurement report. The method also includes receiving, from the IRS, another reflected transmission of the message originating from the transmission source using one or more configured IRS coefficients that are configured based on the CLI measurement report.

For example, an apparatus may include a transmission controller configured to generate control signals to control transmissions via an antenna array according to a plurality of transmission modes, the plurality of transmission modes including a single-element transmission mode and a multi-element transmission mode. For example, the single-element transmission mode may include a plurality of single-element transmissions via a plurality of single-element antennas. For example, a single-element antenna may include a single antenna element of the antenna array. For example, the multi-element transmission mode may include a plurality of multi-element transmissions via a plurality of multi-element antennas. For example, a multi-element antenna may include two or more adjacent antenna elements of the antenna array. For example, a multi-element transmission via the multi-element antenna may include a simultaneous transmission via the two or more adjacent antenna elements.

Provided are a signal detection circuit and a detection method using the signal detection circuit. The signal detection circuit includes a reconfigurable intelligent surface, a multiple input/output circuit connected to the reconfigurable intelligent surface, a magnitude detection circuit connected to the multiple input/output circuit, and a processor connected to the magnitude detection circuit, wherein the reconfigurable intelligent surface includes a sampling area arranged to intersect in a first direction and a second direction, the multiple input/output circuit is configured to receive and process a signal from the sampling area, the magnitude detection circuit is configured to receive the signal from the multiple input/output circuit and detect a magnitude of the received signal, and the processor is configured to identify an incidence direction of the signal based on a detection result of the magnitude detection circuit.

Aspects of the disclosure relate to beam sweeping with controllable reflective surfaces in the presence of co-located base stations of different network operators. A first base station that is co-located at a site with a second base station may perform a first beam sweep. The first beam sweep includes transmitting a plurality of directional beams. The first base station further transmits a control signal to a controllable reflective surface to control the controllable reflective surface to reduce a likelihood of a redirection of a directional beam of a potential second beam sweep by the second base station towards a user equipment associated with the second base station. Other aspects, embodiments, and features are also claimed and described.