Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE) configured with uplink (UL) spatial multiplexing and UL skipping, the UE receives, from a base station, two UL grants for a Transmission Time Interval (TTI). The UE generates two Medium Access Control (MAC) Protocol Data Units (PDUs) for the TTI, wherein a first MAC PDU of the two MAC PDUs is able to accommodate all available data of the UE. The UE transmits the two MAC PDUs to the base station.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives a first Radio Resource Control (RRC) message indicative of switching a Primary Cell (PCell) of the UE to a first cell, wherein the first RRC message is indicative of a first configuration of the first cell. The UE resets a Medium Access Control (MAC) entity associated with the PCell of the UE in response to receiving the first RRC message. The UE receives a second RRC message indicative of a second configuration of a second cell. The UE receives a signaling indicative of initiating a mobility procedure to switch the PCell of the UE to the second cell. The signaling includes a Physical Downlink Control Channel (PDCCH) signaling and/or a MAC Control Element (CE). The UE does not reset the MAC entity associated with the PCell of the UE in response to the mobility procedure.

Abstract: Methods, systems, and apparatuses are provided for User Equipment (UE) Timing Advance (TA) reporting in a wireless communication system. The UE can appropriately trigger the TA report with the different configurations by system information (e.g., for Random Access (RA) procedure, for TA report during RA, etc.) and dedicated signaling (e.g., for Radio Resource Control (RRC) connected mode, for event-triggered TA report, etc.). A method for a UE in a wireless communication system can comprise receiving a first configuration of TA report, receiving a second configuration of TA report, and determining whether to trigger a second TA report upon receiving the second configuration based on whether a first TA report has been transmitted to a serving cell.

Abstract: A method and apparatus are disclosed, from the perspective of a UE, for transmitting UL RS. In one embodiment, the method includes deriving a first transmit power of a first UL RS based on a first power control mechanism, wherein derivation of the first transmit power based on the first power control mechanism is associated with an uplink data channel. In addition, the method includes deriving a second transmit power of a second UL RS based on a second power control mechanism, wherein derivation of the second transmit power based on the second power control mechanism is not associated with the uplink data channel. Furthermore, the method includes transmitting the first UL RS with the first transmit power. The method also includes transmitting the second UL RS with the second transmit power.

Abstract: A method and apparatus are disclosed from the perspective of a first device to perform sidelink communication. In one embodiment, the method includes the first device performing sidelink resource selection or reselection procedure for a sidelink transmission to a second device, wherein the sidelink resource selection or reselection procedure is performed to select at least one sidelink resource from candidate sidelink resources within a time duration of selection window. The method further includes the first device selecting a first sidelink resource based on sidelink active time or wake-up time of the second device, wherein the first sidelink resource is within the time duration of selection window. The method also includes the first device performing the sidelink transmission on the first sidelink resource to the second device.

Abstract: A method and apparatus are disclosed from the perspective of a first device. In one embodiment, the method includes the first device performs sensing on a data resource pool, and the first device selects/derives at least a first data resource from the data resource pool based on the sensing result of the data resource pool. The method further includes the first device transmits a first control information on a first control resource, wherein the first control information allocates or indicates the first data resource. The method also includes the first device performs a first data transmission on the first data resource to at least one second device.

Abstract: A method and apparatus are disclosed from the perspective of a UE (User Equipment). In one embodiment, the method includes the UE receiving and/or monitoring a first control region via a first link. The method further includes the UE transmitting a first request if the first link fails. The method also includes the UE receiving and/or monitoring a second control region for a response via a second link within a time window associated with the first request. In addition, the method includes the UE receiving and/or monitoring the first control region after the time window associated with the first request is over.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE maintains a first counter and a second counter, wherein the first counter and the second counter are associated with a Special Cell (SpCell) and are for counting beam failure instance indications. The UE initiates a first beam failure recovery (BFR) procedure based on the first counter being equal to or larger than a value, wherein the first BFR procedure includes initiating a random access procedure for SpCell BFR associated with the SpCell. The UE sets the first counter and the second counter to a defined value in response to completion of the first BFR procedure.

Abstract: Methods and devices are disclosed from the perspective of a first wireless transmit/receive unit (WTRU). In one method, the method includes triggering a first buffer status report (BSR), wherein the first BSR indicates an estimated amount of data expected to arrive.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), a configuration for monitoring downlink control information (DCI) indicative of a slot format may be received. In some examples, the configuration indicates the UE to monitor a first DCI in a first monitoring occasion associated with a slot and to monitor a second DCI in a second monitoring occasion. The first DCI is indicative of the slot format. Configured transmission and/or configured reception may be performed on one or more symbols when the first DCI is not received in the first monitoring occasion, the second DCI is received in the second monitoring occasion and the second DCI is indicative of the slot format for the slot. The one or more symbols are configured as flexible by a Radio Resource Control (RRC) configuration. The one or more symbols are in the slot.

Abstract: In an example, a second UE receives a first SCI and a second SCI from a first UE in a first slot. A groupcast sidelink transmission is scheduled by the first SCI and the second SCI. The second SCI indicates a location indication, associated with a location of the first UE, and a communication range. A PSFCH resource is determined based upon the first SCI. The second UE doesn't transmit a NACK indication on the PSFCH resource if location information of the second UE is available, the groupcast sidelink transmission isn't successfully decoded, and the second UE is outside the communication range. The second UE transmits the NACK indication on the PSFCH resource if the location information isn't available and the groupcast sidelink transmission isn't successfully decoded, or if the location information is available, the groupcast sidelink transmission isn't successfully decoded, and the second UE is within the communication range.

Abstract: A method and apparatus are disclosed from the perspective of a UE (User Equipment). In one embodiment, the method includes the UE being configured with a control resource set (CORESET). The method further includes the UE receiving a Downlink Control Information (DCI) on the CORESET, wherein an index is included in the DCI and the index indicates a time domain resource allocation pattern. The method also includes the UE receiving data in Orthogonal Frequency Division Multiplexing (OFDM) symbols determined according to the time domain resource allocation pattern, wherein a range of the time domain resource allocation pattern starts from the first OFDM symbol of the CORESET or after an offset from the first OFDM symbol of the CORESET, and the range of the time domain resource allocation pattern may end across a slot boundary.

Abstract: In an example, a device receives a first sidelink control information in a first sidelink Transmission Time Interval (TTI) in a sidelink resource pool. The first sidelink control information is indicative of a first sidelink resource in a second sidelink TTI. The device determines a conflict associated with the first sidelink resource. The device determines a transmission occasion for a first sidelink transmission with conflict information. The device determines a plurality of sidelink transmissions in the transmission occasion. The plurality of sidelink transmissions comprises a first set of sidelink transmissions with conflict information, and/or a second set of sidelink transmissions with sidelink Hybrid Automatic Repeat Request (HARQ) feedback. The first set of sidelink transmissions comprise the first sidelink transmission. The device determines one or more sidelink transmissions of the plurality of the sidelink transmissions.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives, via a Radio Resource Control (RRC) message, a resource configuration of a first configured grant to be used in RRC inactive state. The UE performs a first new transmission using the first configured grant in RRC inactive state. After the performing the first new transmission, the UE receives an uplink grant in RRC inactive state via Physical Downlink Control Channel (PDCCH). The UE determines whether the uplink grant is for performance of a second new transmission or for performance of a first retransmission. The UE performs the second new transmission using the uplink grant in RRC inactive state if the UE determines that the uplink grant is for performance of the second new transmission.

Abstract: A method and device are disclosed for a remote User Equipment (UE) to support UE-to-Network relay communication. The remote UE establishes a PC5 connection with a first relay UE for a relay communication with a first network node. The remote UE also performs a Radio Resource Control (RRC) connection establishment procedure with the first network node via the first relay UE. Furthermore, the remote UE transmits a first RRC message to a second network node via a second relay UE for requesting RRC connection re-establishment, wherein the first RRC message includes a first Cell Radio Network Temporary Identifier (C-RNTI) of the remote UE. Also, the remote UE receives a second RRC message from the second network node via the second relay UE for re-establishing a RRC connection between the second network node and the remote UE, wherein the second RRC message includes a second C-RNTI of the remote UE.

Abstract: A method and apparatus are disclosed from the perspective of a first UE (User Equipment) in RRC_CONNECTED to detect configuration failure. In one embodiment, the method includes the first UE transmitting a first PC5 RRC (Radio Resource Control) message to a second UE, wherein the first PC5 RRC message includes an AS (Access Stratum)-layer configuration for a unicast link established with the second UE. The method also includes the first UE transmitting a fourth RRC message to a network node if a configuration failure of the AS-layer configuration is detected, wherein the fourth RRC message indicates the configuration failure occurs.

Abstract: A method and apparatus for implementing reference signal transmissions in a wireless communication system. In one embodiment, the method includes the cell, transmission point (TP), or transmission and reception point (TRP) broadcasting a first RS periodically for measurement, wherein the first RS is transmitted at multiple occasions (or timings) in each period on different beams. The method also includes the cell, TP, or TRP transmitting a second RS to a UE for PDCCH demodulation, wherein the second RS is transmitted on multiple beams in a beam set of the UE in a subframe (or symbol) in which the PDCCH is transmitted.

Abstract: A method and device are disclosed for Sidelink Relay Adaptation Protocol (SRAP) Data Protocol Data Unit (PDU) discarding. In one embodiment, the method includes a relay UE establishing a PC5 connection with a remote UE. The method further includes the relay UE receiving a SRAP Data PDU from the remote UE. The method also includes the relay UE preventing from discarding the SRAP Data PDU if the SRAP Data PDU is the first SRAP Data PDU received from the remote UE via SL-RLC1, wherein a header of the first SRAP Data PDU contains a UE Identity/Identifier (ID) of the remote UE, and the UE ID of the remote UE is not included in any SRAP configuration of the relay UE.

Abstract: A method and device are disclosed from the perspective of a remote UE. In one embodiment, the method includes the remote UE establishing a first unicast link with a relay UE. The method also includes the remote UE establishing a Radio Resource Control (RRC) connection with a network node via the relay UE. The method further includes the remote UE establishing a second unicast link with a second UE. In addition, the method includes the remote UE detecting a sidelink radio link failure. Furthermore, the method includes the remote UE initiating or performing a RRC connection re-establishment procedure if the sidelink radio link failure occurs on the first unicast link. The method also includes the remote UE initiating or performing a Sidelink UE Information procedure if the sidelink radio link failure occurs on the second unicast link.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives an uplink (UL) grant. The UL grant is indicative of a first Physical Uplink Shared Channel (PUSCH) transmission on a first Transmission/Reception Point (TRP) of a first cell. The UL grant is indicative of a second PUSCH transmission on a second TRP of the first cell. The UE transmits a Power Headroom Reporting (PHR) Medium Access Control (MAC) Control Element (CE). Based on the UL grant, the PHR MAC CE is indicative of a first power headroom (PH), associated with the first TRP, based on a real PUSCH transmission, and is indicative of a second PH, associated with the second TRP, based on a reference PUSCH transmission. The second PUSCH transmission is performed after transmitting the PHR MAC CE.