An n input, radio frequency (RF) signal matrix is formed of a plurality of two-to-one RF signal routing units each including first, second, and third switching units selectively connecting either a first input to an output via a bypass conductive path while electrically isolating first and second signal combining conductive paths from the output or first and second inputs to the output via first and second signal combining conductive paths while electrically isolating the bypass conductive path from the output. The RF signal routing units are connected in at least two levels with outputs from a first level connected to inputs for a second level to form the n inputs for the RF signal matrix. Any number of the n inputs may be employed without unused inputs loading the output.

Embodiments of the present disclosure describe systems, devices, and methods that may provide channel estimation and compensation in high speed scenarios, which may include user equipment carried on a high speed train. Embodiments may employ cell-specific reference signal (CRS)-based time-domain channel estimation and compensation.

Embodiments of the present disclosure describe systems, devices, and methods that may provide channel estimation and compensation in high speed scenarios, which may include user equipment carried on a high speed train. Embodiments may employ cell-specific reference signal (CRS)-based time-domain channel estimation and compensation.

A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.

A multiple-access transceiver handles communications with mobile stations in environments that exceed mobile station design assumptions without necessarily requiring modifications to the mobile stations. One such environment is in Earth orbit. The multiple-access transceiver is adapted to close communications with mobile stations while exceeding mobile station design assumptions, such as greater distance, greater relative motion and/or other conditions commonly found where functionality of a terrestrial transceiver is to be performed by an orbital transceiver. The orbital transceiver might include a data parser that parses a frame data structure, a signal timing module that adjusts timing based on orbit to terrestrial propagation delays, frequency shifters and a programmable radio capable of communicating from the Earth orbit that uses a multiple-access protocol such that the communication is compatible with, or appears to the terrestrial mobile station to be, communication between a terrestrial cellular base station and the terrestrial mobile station.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive one or more reference signals associated with a downlink communication. The UE may transmit an indication of a preferred demodulation reference signal (DMRS) configuration to be used for the downlink communication, the preferred DMRS configuration based at least in part on the one or more reference signals and a transmission mode associated with the preferred DMRS configuration. Numerous other aspects are described.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive one or more reference signals associated with a downlink communication. The UE may transmit an indication of a preferred demodulation reference signal (DMRS) configuration to be used for the downlink communication, the preferred DMRS configuration based at least in part on the one or more reference signals and a transmission mode associated with the preferred DMRS configuration. Numerous other aspects are described.

Methods are proposed to define UE behavior for performing synchronization signal block (SSB) based radio link monitoring (RLM) and channel state information reference signal (CSI-RS) based RLM. In a first novel aspect, if CSI-RS based RLM-RS is not QCLed to any CORESET, then UE determines that CSI-RS RLM configuration is error and does not perform RLM accordingly. In a second novel aspect, SSB for RLM and RLM CSI-RS resources are configured with different numerologies. UE perform SSB based RLM and CSI-RS based RLM based on whether the SSB and CSI-RS resources are TDMed configured by the network. In a third novel aspect, when multiple SMTC configurations are configured to UE, UE determines an SMTC period and whether SMTC and RLM-RS are overlapped for the purpose of RLM evaluation period determination.

Methods are proposed to define UE behavior for performing synchronization signal block (SSB) based radio link monitoring (RLM) and channel state information reference signal (CSI-RS) based RLM. In a first novel aspect, if CSI-RS based RLM-RS is not QCLed to any CORESET, then UE determines that CSI-RS RLM configuration is error and does not perform RLM accordingly. In a second novel aspect, SSB for RLM and RLM CSI-RS resources are configured with different numerologies. UE perform SSB based RLM and CSI-RS based RLM based on whether the SSB and CSI-RS resources are TDMed configured by the network. In a third novel aspect, when multiple SMTC configurations are configured to UE, UE determines an SMTC period and whether SMTC and RLM-RS are overlapped for the purpose of RLM evaluation period determination.

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.