Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives, from a first cell, a first signaling indicative of one or more random access resources of a second cell. The UE receives, from the first cell, a second signaling indicative of switching a Special Cell (SpCell) of the UE to the second cell, wherein the second signaling comprises at least one of a Physical Downlink Control Channel (PDCCH) signaling or a Medium Access Control (MAC) Control Element (CE). The UE initiates a random access procedure on the second cell in response to receiving the second signaling, wherein the random access procedure is performed by the UE using the one or more random access resources.

Abstract: Methods, systems, and apparatuses for Sidelink Discontinuous Reception (SL DRX) in a wireless communication system to avoid ambiguity on slot offset calculations on SL DRX. A method for a UE comprises performing a SL communication associated with a destination Identity (ID), having a SL DRX configuration associated with the SL communication, wherein the SL DRX configuration comprises at least an on-duration timer and a DRX cycle, deriving a first offset associated with the SL communication based on the destination ID and the DRX cycle, deriving a second offset associated with the SL communication based on the destination ID and a number of slots per subframe, starting the on-duration timer after a time period determined based on the second offset from the beginning of a subframe, wherein the subframe is determined based on at least the first offset, and monitoring Sidelink Control Information (SCI) when the on-duration timer is running.

Abstract: Methods and apparatuses for handling device-to-device feedback transmission in a wireless communication system are disclosed herein. In one method, a first device receives a configuration for operating in a network scheduling mode for acquiring sidelink resources. The first device receives a sidelink control information with a report request from a second device. The first device triggers or is triggered to transmit a report to the second device in response to the report request. If the first device has no available sidelink resource for transmitting the report, the first device triggers a scheduling request. The first device transmits a signaling of the scheduling request to the network. The first device receives a sidelink grant from the network. The first device utilizes sidelink resource(s) indicated by the sidelink grant to transmit the report to the 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 a first signaling containing mapping between resource allocation mode(s) and attribute(s) of sidelink data of the UE from a base station. The method further includes the UE performing a sidelink transmission of the sidelink data based on the mapping between the resource allocation mode(s) and the attribute(s) of the sidelink data.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a first User Equipment (UE), the first UE generates a message requesting inter-UE coordination information, wherein the message includes information associated with a first priority value. The first UE generates a Medium Access Control (MAC) Protocol Data Unit (PDU) including the message. The first UE sets a value of a priority field in a first sidelink control information (SCI) based on a second priority value of the message, wherein the second priority value of the message is a configured value and/or a lowest priority value among a defined set of priority values. The first UE transmits the first SCI to one or more UEs including a second UE, wherein the first SCI schedules a first Physical Sidelink Shared Channel (PSSCH) transmission for transmitting the MAC PDU.

Abstract: Methods, systems, and apparatuses can comprise receiving a Sidelink (SL) grant, wherein the SL grant indicates a SL transmission, starting or restarting a first timer for a SL Hybrid Automatic Repeat Request (HARQ) process in a first symbol after the end of a Physical Uplink Control Channel (PUCCH) resource associated with the SL grant, or the SL transmission, when the first device does not transmit a SL HARQ feedback for the SL HARQ process on the PUCCH resource due to measurement gap or Listen-Before-Talk (LBT) failure, starting or restarting a second timer for the SL HARQ process in a first symbol, after the first timer expires, when the first device does not transmit the SL HARQ feedback for the SL HARQ process on the PUCCH resource due to measurement gap, or LBT failure, and the SL HARQ feedback is a negative acknowledgement, and monitoring a Physical Downlink Control Channel (PDCCH) when the second timer is running.

Abstract: Methods, systems, and apparatuses are provided for a User Equipment (UE) in a wireless communication system receiving, from a network, a first signaling indicative of cell configuration of a cell, receiving, from the network, a second signaling indicative of switching a Special Cell (SpCell) of the UE to the cell or adding the cell as a serving cell, receiving, from the network, a third signaling indicative of a first time alignment information associated with the first Timing Advance Group (TAG), and in response to the second signaling: (1) switching the SpCell of the UE to the cell or adding the cell as the serving cell, (2) applying the first time alignment information on the first TAG, and (3) initiating a random access procedure on the cell when no time alignment information associated with the second TAG is in the third signaling.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a first device configured with a plurality of carriers/cells for sidelink communication, the first device determines a first sidelink message for transmission to a first destination associated with a first set of carriers/cells of the plurality of carriers/cells. The first device triggers, based on the first sidelink message, a first scheduling request to a network node. The first device transmits a first signaling of the first scheduling request to the network node. The first signaling includes first information associated with the first destination and/or second information associated with the first set of carriers/cells.

Abstract: Methods, systems, and apparatuses are provided for configuring sidelink (SL) configured grant configuration in SL carrier aggregation. A method for a first device in a wireless communication system can comprise receiving a first sidelink configured grant configuration, wherein the first sidelink configured grant configuration indicates and/or includes a first frequency information and one or more first SL resources, and performing one or more first SL transmissions via the one or more first SL resources on a first SL frequency indicated by the first frequency information.

Abstract: Methods, systems, and apparatuses can comprise receiving a Sidelink (SL) grant, wherein the SL grant indicates a SL transmission, starting or restarting a first timer for a SL Hybrid Automatic Repeat Request (HARQ) process in a first symbol after the end of a Physical Uplink Control Channel (PUCCH) resource associated with the SL grant, or the SL transmission, when the first device does not transmit a SL HARQ feedback for the SL HARQ process on the PUCCH resource due to measurement gap or Listen-Before-Talk (LBT) failure, starting or restarting a second timer for the SL HARQ process in a first symbol, after the first timer expires, when the first device does not transmit the SL HARQ feedback for the SL HARQ process on the PUCCH resource due to measurement gap, or LBT failure, and the SL HARQ feedback is a negative acknowledgement, and monitoring a Physical Downlink Control Channel (PDCCH) when the second timer is running.

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 for a User Equipment (UE) in a wireless communication system can comprise receiving, from a first cell, a first signaling indicative of a configuration of at least a second cell, receiving, from the first cell, a second signaling to switch a Special Cell (SpCell) of the UE to the second cell, wherein the second signaling comprises at least one of a Physical Downlink Control Channel (PDCCH) signaling or a Medium Access Control (MAC) Control Element (CE), performing a procedure to switch the SpCell of the UE in response to the second signaling, performing one or more actions in response to detecting a failure of the procedure, including: initiating a random access procedure on the second cell, transmitting a report to a network of the first cell, wherein the report indicates the unsuccessful switching of the SpCell to the second cell, or initiating a RRC connection re-establishment procedure.

Abstract: Methods, systems, and apparatuses for Sidelink Discontinuous Reception (SL DRX) in a wireless communication system to avoid ambiguity on slot offset calculations on SL DRX. A method for a UE comprises performing a SL communication associated with a destination Identity (ID), having a SL DRX configuration associated with the SL communication, wherein the SL DRX configuration comprises at least an on-duration timer and a DRX cycle, deriving a first offset associated with the SL communication based on the destination ID and the DRX cycle, deriving a second offset associated with the SL communication based on the destination ID and a number of slots per subframe, starting the on-duration timer after a time period determined based on the second offset from the beginning of a subframe, wherein the subframe is determined based on at least the first offset, and monitoring Sidelink Control Information (SCI) when the on-duration timer is running.

Abstract: Methods, systems, and apparatuses are provided for enhancing timing alignment for uplink (UL) multi-Transmission/Reception Point (TRP) (or mTRP) scenarios in a wireless communication system. A method for a UE in a wireless communication system can comprise receiving a signaling, wherein the signaling indicates activation for a first TRP and/or is a Physical Downlink Control Channel (PDCCH) signal, determining to perform a first random access procedure on the first TRP, based on the signaling, to obtain a first Time Alignment (TA) information associated with the first TRP, and performing multi-TRP operation on the first TRP associated with the first TA information and a second TRP associated with a second TA information.

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: 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. 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: A method and apparatus are disclosed. In an example from the perspective of a first User Equipment (UE), the first UE generates a message requesting inter-UE coordination information, wherein the message includes information associated with a first priority value. The first UE generates a Medium Access Control (MAC) Protocol Data Unit (PDU) including the message. The first UE sets a value of a priority field in a first sidelink control information (SCI) based on a second priority value of the message, wherein the second priority value of the message is a configured value and/or a lowest priority value among a defined set of priority values. The first UE transmits the first SCI to one or more UEs including a second UE, wherein the first SCI schedules a first Physical Sidelink Shared Channel (PSSCH) transmission for transmitting the MAC PDU.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives a first signaling indicating a configuration of a first cell, wherein the first cell is associated with a first timing advance group (TAG). The UE receives a second signaling indicative of addition of the first cell as a first Serving Cell. In response to the second signaling, the UE (i) adds the first cell as the first Serving Cell, and (ii) determines whether to initiate a random access procedure based on the second signaling, and/or based on whether the first cell is associated with a first valid timing advance value.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives a first signaling configuring one or more sets of cells including a first set of cells. The first set of cells includes a first Special Cell (SpCell) and one or more Secondary Cells (SCells). The UE receives receiving a second signaling indicative of a change of Serving Cells of the UE to the first set of cells. In response to the second signaling, the UE adds and/or activates the first SpCell and the one or more SCells.