A Search and Rescue (SAR) system is disclosed. The SAR system may include a receiver or transmitter node. The receiver or transmitter node may include a communications interface with at least one antenna element and a controller. The controller may include one or more processors and have information of own node velocity and own node orientation relative to a common reference frame. The receiver or transmitter node may be time synchronized to apply Doppler corrections associated with the receiver or transmitter node’s own motions relative to the common reference frame. For example, the transmitter node may serve as an emergency locator beacon and mark a location of interest, and the receiver node may determine the marked location of interest based at least on the Doppler corrections.

A system is disclosed. The system may include a receiver or transmitter node. The receiver or transmitter node may include a communications interface with an antenna element. A controller may include one or more processors and have information of own node velocity and own node orientation relative to a common reference frame. The receiver or transmitter node may be time synchronized to apply Doppler corrections to signals, the Doppler corrections associated with the receiver or transmitter node's own motions relative to the common reference frame, the Doppler corrections applied using Doppler null steering along Null directions. The system may be configured to, via the Doppler null steering, at least one of: track an expendable asset of the system relative to a target; discover a rendezvous node; or identify at least one of a network relay node or a relay location for a network relay node.

System and method for adjusting timing error in a mobile device. In the mobile device, a crystal oscillator (XO) is used by a system timer as the timing source. When the mobile device enters into a sleep mode, the system timer is set to time the duration of the sleep mode. During the sleep mode, a thermistor is used to measure and monitor the temperature changes of the XO. After the sleep mode is over, a processor in the mobile device determines the frequency changes of the XO based on the temperature changes of the XO. Based on the frequency changes of the XO, the processor determines the timing error that may have occurred when the system timer was timing the sleep mode and determines the actual duration of the sleep mode by adjusting the duration timed by the system timer based on the timing error.

A device may selectively listen for a tracking reference signal (TRS) during connected mode discontinuous reception (CDRx) based on whether the device is to switch between repeaters of a base station (such as during travel). A device may determine whether the device is in a high speed train (HST) scenario (such as based on a difference in frequency errors generated using a synchronization signal block (SSB) and generated using a TRS, based on a trajectory of a frequency error or a frequency error difference over time, based on instantaneous frequency errors, etc.). When the device is in a HST scenario, the device listens for a TRS during CDRx, and the device generates a frequency error using the TRS. When the device is not in a HST scenario, the device prevents listening for a TRS during CDRx (with a SSB received during CDRx to be used to generate a frequency error).

Aspects of the subject disclosure may include, for example, determining that interference associated with a signal exceeds a threshold, determining at least one operating parameter associated with a user equipment to modify responsive to the determining that the interference exceeds the threshold, wherein the at least one operating parameter includes a frequency band that the user equipment uses to communicate or a clock signal frequency range of a clock of the user equipment, and transmitting a notification to the user equipment, wherein the notification includes an indication of the at least one operating parameter. Other embodiments are disclosed.

Systems and associated methods for reducing Doppler shifts in the broadband signals between Unmanned Aerial Vehicles (UAVs) and ground stations are disclosed herein. In one embodiment, a method for reducing the Doppler shift of wireless signals includes estimating a velocity of the UAV based on a Global Positioning System (GPS) or an Inertial Measurement Unit (IMU) of the UAV and calculating the Doppler shift of an upload (UL) wireless signal based on the velocity of the UAV. The method further includes predistorting a frequency of the UL wireless signal at the ground station to reduce the Doppler shift at a UAV receiver (RX) and transmitting the UL wireless signal from a ground station transmitter (TX) to the UAV RX. In some embodiments, calculating the Doppler shift of the UL wireless signal is performed at the ground station.

Methods and devices for configuring an initial active downlink bandwidth part as part of an initial access procedure are provided. In one provided method, a base station broadcasts a synchronization signal block (SSB) that includes a control resource set CORESET) configuration index. The CORESET configuration index is one of a plurality of CORESET configuration indexes, each CORESET configuration index being associated with a respective configuration of a CORESET. Each configuration includes a CORESET frequency size, a CORESET time duration, and a frequency offset of the CORESET with respect to the SSB selected from a set of predefined frequency offsets. The initial active downlink bandwidth part is defined as having the same frequency location and bandwidth as the CORESET. The base station transmits, as part of a physical downlink control channel (PDCCH) within the CORESET, information indicating scheduling of remaining minimum system information (RMSI) in a physical downlink shared channel (POSCH).

The present invention is to generate a spatially phase modulated electron wave. A laser radiating apparatus, a spatial light phase modulator, and a photocathode are provided. The photocathode has a semiconductor film having an NEA film formed on a surface thereof, and a thickness of the semiconductor film is smaller than a value obtained by multiplying a coherent relaxation time of electrons in the semiconductor film by a moving speed of the electrons in the semiconductor film. According to the configuration, a spatial distribution of phase and a spatial distribution of intensity of spatial phase modulated light are transferred to an electron wave, and the electron wave emitted from an NEA film is modulated into the spatial distribution of phase and the spatial distribution of intensity of the light. Since the spatial distribution of phase of the light can be modulated as intended by a spatial phase modulation technique for light, it is possible to generate an electron wave having a spatial distribution of phase modulated as intended.

Provided is a synchronization method, which includes: a first device periodically sends a first PSS sequence and first PDSCH control information at frequency points F.sub.1 to F.sub.N in sequence, where the first PSS sequence and the first PDSCH control information are used for a second device to detect the first PSS sequence and detect the first PDSCH control information; the first device receives signals at frequency points f.sub.1 to f.sub.M in sequence and detects a second PSS sequence; when the second PSS sequence is detected, the first device obtains second half-frame synchronization information and detects second PDSCH control information according to the second half-frame synchronization information; and when the second PDSCH control information is detected, the first device obtains second frame synchronization information and enters a synchronization state. Also provided are a synchronization device, a synchronization system, and a computer-readable storage medium.

A signal transmission method is provided. The method includes: determining a target device, and transmitting a 5G signal to the target device, where the 5G signal includes a synchronization block, and the synchronization block is used to carry a PBCH, a PSS, an SSS and a DMRS, and the DMRS and the SSS are used as references for a demodulation result of the PBCH. By further setting the DMRS in the synchronization block, both the SSS and the DMRS are used as the references for the demodulation result of the PBCH, thereby ensuring that an adjusted phase of the demodulation result is as same as possible to a phase of the synchronization block before modulation of a transmission device, which greatly eliminates influence of factors such as the Doppler effect on the phase of the synchronization block during a signal transmission process.