Abstract: Various solutions for slot aggregation design in non-terrestrial network (NTN) communications with respect to user equipment and network apparatus in mobile communications are described. An apparatus may receive a demodulation reference signal (DMRS) time bundling configuration. The apparatus may determine a duration interval of the DMRS time bundling configuration. The apparatus may perform channel estimation cross slots based on the duration interval.

Abstract: Solutions pertaining to spectrum sharing between a terrestrial network (TN) and a non-terrestrial network (NTN) with interference control are proposed. An apparatus implemented in a UE communicates with a non-terrestrial (NT) network node of the NTN by resource sharing with the TN. There is a requirement on either or both of a directive gain and a directive emission power with respect to a network node of the TN such that interference between TN downlink (DL) transmissions and NTN uplink (UL) transmissions is less than a threshold.

Abstract: 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.

Abstract: Various solutions for slot aggregation design in non-terrestrial network (NTN) communications with respect to user equipment and network apparatus in mobile communications are described. An apparatus may receive a demodulation reference signal (DMRS) time bundling configuration. The apparatus may determine a duration interval of the DMRS time bundling configuration. The apparatus may perform channel estimation cross slots based on the duration interval.

Abstract: Solutions pertaining to spectrum sharing in coordination between a non-terrestrial network (NTN) and a terrestrial network (TN) are proposed. An apparatus implemented in a UE measures a signal strength of each of one or more TN cells and one or more NTN cells. The apparatus reports a result of the measuring to a TN. The apparatus also receives an indication from the TN configuring and activating a bandwidth part (BWP) that separates transmission by a base station of the TN from NTN downlink (DL) transmissions.

Abstract: Solutions pertaining to configuration of spectrum sharing between a terrestrial network (TN) and a non-terrestrial network (NTN) are proposed. An apparatus implemented in a UE communicates with a non-terrestrial (NT) network node of the NTN by resource sharing with the TN. The resource sharing involves resource sharing with pairing of uplink (UL) and downlink (DL) transmissions of the NTN and the TN.

Abstract: Solutions pertaining to enhanced support for transmit-receive (Tx-Rx) gap in non-terrestrial network (NTN) communications are proposed. An apparatus implemented in a UE receives from a non-terrestrial (NT) network node of a network an uplink (UL) grant or a configuration that schedules an UL transmission (Tx). The apparatus performs the UL transmission to the NT network node within a transmit-receive (Tx-Rx) transition gap during which no downlink (DL) Tx from the NT network node is expected. The Tx-Rx transition gap includes an UL Tx duration, a pre-UL Tx gap (Gap_start) before a starting time of the UL Tx duration (t_start), and a post-UL Tx gap (Gap_end) after an ending time of the UL Tx duration (t_end). A starting timing of the Tx-Rx transition gap can be expressed as: t_start?timing advance (TA)?Gap_start. An ending time of the Tx-Rx transition gap can be expressed as: t_end?TA+Gap_end.

Abstract: Various solutions for reducing uplink overhead with respect to user equipment and network apparatus in mobile communications are described. An apparatus may monitor a downlink channel. The apparatus may determining whether downlink control information (DCI) is received on the downlink channel. The apparatus may skip a hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback transmission on an uplink channel in an event that no DCI is received on the downlink channel.

Abstract: Aspects of the disclosure provide an apparatus for transmitting a circularly polarized signal by linearly polarized antennas. Processing circuitry of the apparatus generates a transmitted baseband signal vector. Based on the transmitted baseband signal vector, power amplifiers (PAs) of the apparatus generates transmitted radio frequency (RF) signals. The transmitted RF signals are received by receiving circuitry of the apparatus to obtain a received baseband signal vector. A controller of the apparatus calibrates the PAs and local oscillator (LO) signals of frequency converters of the apparatus based on the received baseband signal vector. A horizontally polarized antenna and a vertically polarized antenna of the apparatus transmit a circularly polarized signal based on the calibrated PAs and the calibrated LO signals.

Abstract: Provided is an apparatus for transmitting a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receives a first circularly polarized signal transmitted based on a transmitted baseband signal vector. Based on the first circularly polarized signal, a radio frequency (RF) module of the apparatus generates a received baseband signal vector including a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector based on the received baseband signal vector and calibrates power amplifiers (PAs) and local oscillator (LO) signals of frequency converters in the RF module based on the estimated receiving polarization vector.

Abstract: Aspects of the disclosure provide an apparatus for receiving a circularly polarized signal by linearly polarized antennas. A horizontally polarized antenna and a vertically polarized antenna of the apparatus receive a circularly polarized signal that is transmitted based on a transmitted baseband signal vector. A radio frequency (RF) module of the apparatus generates a first baseband signal vector based on the received circularly polarized signal. The first baseband signal vector includes a product of the transmitted baseband signal vector and a receiving polarization vector of the transmitted baseband signal vector. Processing circuitry of the apparatus estimates the receiving polarization vector of the transmitted baseband signal vector based on the first baseband signal vector. The processing circuitry derives a second baseband signal vector based on the estimated receiving polarization vector and the first baseband signal vector.

Abstract: Apparatus and methods are provided for determining epoch time in an NTN system resolving the SFN wrapping issue. In one novel aspect, the UE obtains epoch time information, determines the epoch-time SFN by selecting one SFN instance with the SFN value indicated in the epoch time information based on one or more epoch-time rules, wherein the epoch-time rules resolve epoch-time SFN ambiguity indicated by the received epoch time information, and derives the epoch time based on the determined epoch-time SFN. In one embodiment, the epoch-time SFN is determined based on the receiving-SFN/SIBx and the SFN value of the epoch-time. The epoch-time SFN is a current or next upcoming SFN with the epoch-time SFN value after the receiving-SFN. The epoch-time SFN is a nearest SFN to the receiving-SFN with the epoch-time SFN value.

Abstract: Various solutions for random access channel (RACH) preamble design in non-terrestrial network (NTN) communications with respect to user equipment and network apparatus are described. An apparatus may initiate a RACH procedure. The apparatus may determine a fractional frequency offset pattern or a cover code across groups of preamble sequences. The apparatus may generate a RACH preamble signal according to at least one of the fractional frequency offset pattern and the cover code. The apparatus may transmit the RACH preamble signal to a network node.

Abstract: Various solutions for satellite access network (SAN) or non-terrestrial network (NTN) measurement and data scheduling with respect to user equipment and network apparatus in mobile communications are described. An apparatus may determine whether to perform a measurement outside a measurement gap for a neighboring cell. The apparatus may apply a scheduling restriction within a time period in an event that the measurement is determined. The apparatus may transmit uplink symbols or receiving downlink symbols outside the time period with the scheduling restriction.

Abstract: A communication apparatus includes a transceiver and a processor. The transceiver is configured to transmit and receive wireless signal. The processor is coupled to the transceiver and configured to perform operations comprising: establishing, via the transceiver, a wireless connection with a network node of a non-terrestrial network (NTN); and transmitting, via the transceiver, a timing advance (TA) report to the network node. The processor is configured to perform auto-compensation of time delays in signaling and a TA value is indicated in the TA report.

Abstract: Various solutions for system information design for synchronization in non-terrestrial network (NTN) communications are described. An apparatus (e.g., a UE) determines synchronization information with respect to an implicit time reference associated with a wireless network. Using the synchronization information, the apparatus maintains synchronization in performing NTN communications with the wireless network.

Abstract: Various solutions for system information design for synchronization in non-terrestrial network (NTN) communications are described. An apparatus (e.g., a UE) receives synchronization information from a wireless network. Using the synchronization information, the apparatus maintains synchronization in performing NTN communications with the wireless network.

Abstract: Various solutions for indicating power saving information with respect to user equipment and network apparatus in mobile communications are described. An apparatus may enter into a power saving mode. The apparatus may monitor a downlink control information (DCI) format while in the power saving mode. The apparatus may determine whether the DCI format is detected. The apparatus may wake up from the power saving mode in an event that the DCI format is not detected.

Abstract: Various solutions for beam utilization management in in non-terrestrial network (NTN) communications are described. An apparatus (e.g., a UE) obtains a duty cycle configuration with respect to a duty cycle of one or more beams of a set of beams of a cell in NTN communications. The apparatus then performs a task according to the duty cycle configuration.

Abstract: Various solutions for uplink synchronization in non-terrestrial network (NTN) communications are proposed. An apparatus implemented in a user equipment (UE) receives a system information block (SIB) of a target cell via a non-terrestrial (NT) network node of the NTN. The apparatus obtains an explicit epoch time from the SIB of the target cell. Then, the apparatus performs an uplink (UL) synchronization with the target cell through adjusting an uplink transmit time according to the explicit epoch time.