Methods, systems, and devices for wireless communication are described. A base station may transmit a set of synchronization signals (SSs) with a first periodicity to a channel engineering device and one or more other wireless devices. The base station may transmit a message to configure the channel engineering device with one or more signaling directions and a second periodicity for the channel engineering device to transmit the set of SS, the second periodicity different from the first periodicity. The one or more signaling directions and the second periodicity may be configured for adjusting a coverage area of the set of SS after transmission from the base station. The base station may receive, from a user equipment (UE) or other wireless device, a second message that includes an indication of whether the set of SS were received by the UE directly from the base station or via the channel engineering device.

A method is disclosed for estimating one or more user terminal locations over a target coverage area by wireless signals transmitted by one or more access points and reflected by one or more reconfigurable intelligent surface panels. The method includes transmission of one or more pilot signals by each of the one or more access points, reflecting, by at least one of the one or more reconfigurable intelligent surface panels, the one or more pilot signals according to one or more predetermined reflection patterns, receiving the reflections by the user terminal, extracting one or more features from the reflections, and estimating of a user terminal location by a method based on a database comprising pairs of locations and the one or more features.

A method for establishing a direct communication using an unmanned aerial vehicle (UAV) with a reconfiguration intelligent surface (RIS) includes configuring RIS parameters based on compensating for undesired oscillations of a position and an orientation associated with the UAV. A signal reflection associated with a beam signal is steered to a target area based on the RIS parameters and by the RIS of the UAV. The signal beam is from a transmitter.

Methods, systems, and devices for wireless communication are described. A base station may transmit a set of synchronization signals (SSs) with a first periodicity to a channel engineering device and one or more other wireless devices. The base station may transmit a message to configure the channel engineering device with one or more signaling directions and a second periodicity for the channel engineering device to transmit the set of SS, the second periodicity different from the first periodicity. The one or more signaling directions and the second periodicity may be configured for adjusting a coverage area of the set of SS after transmission from the base station. The base station may receive, from a user equipment (UE) or other wireless device, a second message that includes an indication of whether the set of SS were received by the UE directly from the base station or via the channel engineering device.

A method for performing monitoring, commissioning, upgrading, analyzing, load balancing, remediating, and optimizing the operation, control, and maintenance of a plurality of remotely located RF signal repeater devices in a wireless network arranged to operate as an Internet of Things (IoT) network. Electronic RF signal repeater devices are employed as elements in the wireless network and communicate wireless radio frequency (RF) signals for a plurality of users. An RF signal repeater device may be arranged to operate as a donor unit device that provides RF signal communication between one or more remotely located wireless base stations, or other donor unit devices on the wireless network. Also, an RF signal repeater device may be arranged to operate as a service unit device that provides wireless RF signal communication between one or more user equipment devices (UEs) and a donor unit device or a wireless base station.

Methods, systems, and devices for wireless communications are described. A channel engineering device may receive control signaling that triggers the channel engineering device to perform one or more angle of arrival (AoA) measurements on one or more reference signals and transmit an AoA measurement report based on the AoA measurements. The base station may process the AoA measurement report and send a control message that configures one or more settings at the channel engineering device. The base station may determine a beam shaping configuration that modifies the one or more settings at the channel engineering device to reflect, focus, refract, or filter signal energy of a transmission by the base station toward a user equipment (UE), a transmission by the UE toward the base station, or both. The base station and one or more UEs may communicate using the channel engineering device based on the beam shaping configuration.

Methods, systems, and devices for wireless communications are described. A base station may transmit control signaling including a beam shaping configuration to a channel engineering device. The channel engineering device may apply the beam shaping configuration during a time period in which the base station is communicating with a user equipment (UE). The beam shaping configuration may include one or more parameters that modify one or more deflection settings at the channel engineering device to adjust an electronic metamaterial of the channel engineering device to focus received signal energy, reflect received signal energy, refract received signal energy, filter received signal energy, or any combination thereof. The base station and one or more UEs may communicate using the channel engineering device based on the beam shaping configuration.

Methods, systems, and devices for wireless communications are described. A base station may identify an intelligent reflecting surface device for communications with a user equipment. The base station may determine a reference signal configuration based on the identified intelligent reflecting surface device. The reference signal configuration may include a first set of parameters associated with the intelligent reflecting surface device. The base station may transmit, to the UE, the intelligent reflecting surface device, or both, one or more reference signals in accordance with the first set of parameters. The base station may identify a second set of parameters associated with one or more reflecting elements of the intelligent reflecting surface device.

A multi-layer reconfigurable reflective intelligent surface (RIS). The RIS includes a unit-cell of a reconfigurable intelligent surface. The unit-cell includes a first layer composed of a conductive material and structured according to a sub-wavelength reflective pattern. The first layer reflects an impinging wave at a predetermined phase and steers the reflected impinging wave toward an intended receiver. The unit-cell includes a second layer composed of a first dielectric substrate material. Between the first and second layers, the unit-cell includes a middle layer composed of a second dielectric material having tunable dielectric properties. Tuning a dielectric constant of the second dielectric material modifies the predetermined phase of reflection of the impinging wave.

A design method for an intelligent reflecting surface (IRS) aided terahertz secure communication system is provided. The IRS aided terahertz multi-input single-output (MISO) system includes a base station (BS) equipped with N.sub.BS antennas, an IRS equipped with N.sub.IRS reflecting elements, a single-antenna user and a single-antenna eavesdropper. The BS transmits signals by the active hybrid beamforming to the relay of the IRS, and the IRS adjusts the signals and reflects the signals to the mobile user, which suppresses the received signal of the eavesdropper. The present invention maximizes the downlink secrecy rate by establishing a joint optimization function and maximizes the system data transmission rate by a cross-entropy based search method.