Various solutions for synchronization in non-terrestrial network (NTN) communications are proposed. An apparatus implemented in a user equipment (UE) obtains at least one of a downlink (DL) pre-compensated frequency value applied on a service link from a satellite of a non-terrestrial network (NTN) and a feeder link delay drift rate of a feeder link between a network node and the satellite. The apparatus further obtains a Doppler frequency shift value. Then, the apparatus performs a timing compensation through adjusting a sampling rate according to at least one of the DL pre-compensated frequency value, the feeder link delay drift rate, and the Doppler frequency shift value.

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may transmit a sounding reference signal (SRS) in multiple slots. A network entity may determine precoding weights in three domains based on the SRS and output reference signals that are precoded based on the precoding weights. The network entity may output control signaling that indicates reference signal resource grouping information that the UE is to use for channel estimations. The reference signal resource grouping information may specify whether the ports in one group are precoded with identical or different spatial, frequency, and time domain weights. A UE may receive the precoded reference signals and the grouping information and report estimated channel metrics and an indication of selected ports per group to the network entity. The network entity may determine precoding in three domains for subsequent downlink communications.

Techniques for compensating for frequency offset of a frequency used in a translation of a signal from a first band to a second band may include using a frequency reference signal located in a different band from an information-bearing signal, where the different band may be a guard band. The frequency reference signal may be offset from a particular frequency, which may be a center frequency, of the information-bearing signal by a known amount. The frequency reference signal may be received by the transmitting station, a frequency offset may be derived, and the frequency offset may be used to pre-compensate further transmitted signals. At another station, the received frequency reference signal may be used to lock a local oscillator for demodulation and/or transmission of the information-bearing signal based on the known offset of the frequency reference signal from the frequency of the information-bearing signal.

Techniques for compensating for frequency offset of a frequency used in a translation of a signal from a first band to a second band may include using a frequency reference signal located in a different band from an information-bearing signal, where the different band may be a guard band. The frequency reference signal may be offset from a particular frequency, which may be a center frequency, of the information-bearing signal by a known amount. The frequency reference signal may be received by the transmitting station, a frequency offset may be derived, and the frequency offset may be used to pre-compensate further transmitted signals. At another station, the received frequency reference signal may be used to lock a local oscillator for demodulation and/or transmission of the information-bearing signal based on the known offset of the frequency reference signal from the frequency of the information-bearing signal.

Techniques for compensating for frequency offset of a frequency used in a translation of a signal from a first band to a second band may include using a frequency reference signal located in a different band from an information-bearing signal, where the different band may be a guard band. The frequency reference signal may be offset from a particular frequency, which may be a center frequency, of the information-bearing signal by a known amount. The frequency reference signal may be received by the transmitting station, a frequency offset may be derived, and the frequency offset may be used to pre-compensate further transmitted signals. At another station, the received frequency reference signal may be used to lock a local oscillator for demodulation and/or transmission of the information-bearing signal based on the known offset of the frequency reference signal from the frequency of the information-bearing signal.

A GSM satellite communication system is in communication with a first satellite having a first field of view including a first plurality of cells in which a plurality of active User Equipment (UEs) is located. The plurality of active UEs is in direct communication with the first satellite. The satellite communication system includes a first feeder link and a first tracking antenna configured to communicate with the plurality of active UEs via the first satellite directly serving the first plurality of cells; a first processing device configured to communicate with the plurality of active UEs; and a second processing device configured to normalize delay for a plurality of beam centers of the first plurality of cells, and provide the normalized delay to the first processing device.

Diversity receiver front end system with impedance matching components. A receiving system can include a controller configured to selectively activate one or more of a plurality of paths between an input of the receiving system and an output of the receiving system. The receiving system can further include a plurality of amplifiers. Each one of the plurality of amplifiers can be disposed along a corresponding one of the plurality of paths and can be configured to amplify a signal received at the amplifier. The receiving system can further include a plurality of impedance matching components. Each one of the plurality of impedance matching components can be disposed along a corresponding one of the plurality of paths and can be configured to reduce at least one of an out-of-band noise figure or an out-of-band gain of the one of the plurality of paths.

Diversity receiver front end system with impedance matching components. A receiving system can include a controller configured to selectively activate one or more of a plurality of paths between an input of the receiving system and an output of the receiving system. The receiving system can further include a plurality of amplifiers. Each one of the plurality of amplifiers can be disposed along a corresponding one of the plurality of paths and can be configured to amplify a signal received at the amplifier. The receiving system can further include a plurality of impedance matching components. Each one of the plurality of impedance matching components can be disposed along a corresponding one of the plurality of paths and can be configured to reduce at least one of an out-of-band noise figure or an out-of-band gain of the one of the plurality of paths.

Systems and methods can support identifying multiple radio transmitters as being integrated within a single communications device. Radio frequency signals may be collected using one or more sensors incorporating radio receivers. A first radio frequency signature and a second radio frequency signature may be identified within one or more of the radio frequency signals as originating respectively from a first radio transmitter and a second radio transmitter. Characteristics of the first and second radio frequency signatures may be analyzed to evaluate a relationship between the first and second radio frequency signatures. It may be determined whether or not the first and second radio transmitters are integrated within a common wireless electronic device based upon the evaluated relationship between the first radio frequency signature and the second radio frequency signature. Characteristics and behaviors associated with the wireless electronic device may be determined therefrom.

Systems and methods can support identifying multiple radio transmitters as being integrated within a single communications device. Radio frequency signals may be collected using one or more sensors incorporating radio receivers. A first radio frequency signature and a second radio frequency signature may be identified within one or more of the radio frequency signals as originating respectively from a first radio transmitter and a second radio transmitter. Characteristics of the first and second radio frequency signatures may be analyzed to evaluate a relationship between the first and second radio frequency signatures. It may be determined whether or not the first and second radio transmitters are integrated within a common wireless electronic device based upon the evaluated relationship between the first radio frequency signature and the second radio frequency signature. Characteristics and behaviors associated with the wireless electronic device may be determined therefrom.