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 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 first User Equipment (UE). In one embodiment, the first UE receives a Radio Resource Control (RRC) message from a network node, wherein the RRC message includes a first sidelink RLC bearer configuration and wherein the first sidelink Radio Link Control (RLC) bearer configuration includes a first index identifying the first sidelink RLC bearer configuration and a first sidelink RLC configuration. The first UE also transmits a first PC5 RRC message to a second UE, wherein the first PC5 RRC message includes the first sidelink RLC bearer configuration. Furthermore, the first UE receives a second PC5 RRC message from the second UE, wherein the second PC5 RRC message includes a second sidelink RLC bearer configuration and wherein the second sidelink RLC bearer configuration includes a second index identifying the second sidelink RLC bearer configuration and a second sidelink RLC configuration.

Abstract: A method and apparatus are disclosed, from the perspective of the UE, for reporting channel state information (CSI). In one embodiment, the method includes a UE being configured with at least two CSI-RS (Channel State Information-Reference Signal) resources. In addition, the method includes the UE performing measurements on the at least two CSI-RS resources. The method also includes the UE generating multiple CSIs according to measurements on the at least two CSI-RS resources, wherein at least one CSI corresponds to measurements on more than one CSI-RS resource. The method further includes the UE reporting at least one of the generated CSIs.

Abstract: A method and device are disclosed from the perspective of a relay UE for Radio Resource Control (RRC) connection establishment to support User Equipment (UE)-to-Network relaying. In one embodiment, the method includes a relay UE establishing a PC5 RRC connection or a PC5 unicast link with a remote UE. The method also includes the relay UE receiving a RRC message from the remote UE. Furthermore, the method includes the relay UE initiating a RRC connection establishment with a network node in response to reception of the RRC message. In addition, the method includes the relay UE transmitting a Disconnect Request message to the remote UE to release the PC5 RRC connection or the PC5 unicast link or transmits a PC5 RRC message to the remote UE to inform the remote UE of a failure of the RRC connection establishment, if the RRC connection establishment fails.

Abstract: A method and device are disclosed from the perspective of a first User Equipment (UE). In one embodiment, the first UE receives a Radio Resource Control (RRC) message from a network node, wherein the RRC message includes a first sidelink RLC bearer configuration and wherein the first sidelink Radio Link Control (RLC) bearer configuration includes a first index identifying the first sidelink RLC bearer configuration and a first sidelink RLC configuration. The first UE also transmits a first PC5 RRC message to a second UE, wherein the first PC5 RRC message includes the first sidelink RLC bearer configuration. Furthermore, the first UE receives a second PC5 RRC message from the second UE, wherein the second PC5 RRC message includes a second sidelink RLC bearer configuration and wherein the second sidelink RLC bearer configuration includes a second index identifying the second sidelink RLC bearer configuration and a second sidelink RLC configuration.

Abstract: A method and device are disclosed from the perspective of a first UE (User Equipment) for changing sidelink identity for a sidelink unicast link associated with a second UE. In one method, the method includes the first UE establishing the sidelink unicast link with the second UE, wherein a first lower-layer identity of the first UE and a second lower-layer identity of the second UE are used for communicating between the first UE and the second UE via the sidelink unicast link. The method also includes the first UE transmitting a Link Identifier Update Request message to the second UE, wherein the Link Identifier Update Request message includes a new first lower-layer identity of the first UE or information for deriving the new first lower-layer identity. The method further includes the first UE receiving a Link Identifier Update Response message from the second UE.

Abstract: A method and apparatus are disclosed from the perspective of a User Equipment (UE). In one embodiment, the method includes the UE receiving from a base station a first information indicating multiple sets of transmission occasions for a signal. The method also includes the UE receiving from the base station a second information indicating an association between a transmission occasion of the signal and a base station beam.

Abstract: A method and apparatus are disclosed from the perspective of a first UE (User Equipment) to update Layer-2 Identities (IDs). In one embodiment, the method includes the first UE establishing a unicast link with a second UE, wherein a first Layer-2 ID of the first UE and a second Layer-2 ID of the second UE are used for data transmission and reception on the unicast link. The method further includes the first UE transmitting a Link Identifier Update Request message for the unicast link to the second UE, wherein the Link Identifier Update Request message includes a new first Layer-2 ID of the first UE. The method also includes the first UE receiving a Link Identifier Update Accept message for the unicast link from the second UE, wherein the Link Identifier Update Accept message includes a new second Layer-2 ID of the second UE.

Abstract: A method and device are disclosed from the perspective of a remote UE. In one embodiment, the remote UE establishes a Radio Resource Control (RRC) connection with a network node. The remote UE also transmits a Layer 2 Identity (L2ID) of the remote UE to the network node. The remote UE further receives a first RRC Reconfiguration message from the network node for path switching from direct to indirect communication, wherein the first RRC Reconfiguration message indicates a relay UE for the path switching. In addition, the remote UE establishes a PC5 connection with the relay UE. Furthermore, the remote UE transmits a first RRC Reconfiguration Complete message corresponding to the first RRC Reconfiguration message to the network node via the relay UE.

Abstract: A method and device are disclosed for supporting multiple connectivity services from the perspective of a remote User Equipment (UE). In one embodiment, the method includes a remote UE establishing a PC5 unicast link with a Layer-2 UE-to-Network relay UE. The method further includes the remote UE establishing at least two connectivity services with at least two data networks over the PC5 unicast link.

Abstract: A method and device are disclosed from the perspective of a remote UE. In one embodiment, the remote UE establishes a Radio Resource Control (RRC) connection with a network node. The remote UE also transmits a Layer 2 Identity (L2ID) of the remote UE to the network node. The remote UE further receives a first RRC Reconfiguration message from the network node for path switching from direct to indirect communication, wherein the first RRC Reconfiguration message indicates a relay UE for the path switching. In addition, the remote UE establishes a PC5 connection with the relay UE. Furthermore, the remote UE transmits a first RRC Reconfiguration Complete message corresponding to the first RRC Reconfiguration message to the network node via the relay UE.

Abstract: A method and apparatus are disclosed from the perspective of a first UE (User Equipment) to request SLRB (Sidelink Radio Bearer) configuration for a unicast link with a second UE. In one embodiment, the method includes the first UE receiving a first message from the second UE, wherein the first message includes a first SLRB configuration for the unicast link. The method further includes the first UE transmitting a second message to a network node to request a second SLRB configuration for the unicast link when the first message is received or a successful transmission of a complete message associated with the first message to the second UE is confirmed.

Abstract: A method and device are disclosed for radio resource allocation to support User Equipment-to-Network (UE-to-Network) relaying. The network node establishes a Radio Resource Control (RRC) connection with a remote UE via a relay UE. The network node transmits a first RRC message to the remote UE via the relay UE, wherein the first RRC message includes a Uu radio bearer configuration and a Sidelink (SL) Radio Link Control (RLC) bearer configuration associated with a data radio bearer (DRB) or a signalling radio bearer (SRB) and wherein the network node is allowed to include a first field used to indicate a configuration for UE autonomous resource selection for sidelink communication transmission in the first RRC message and the network node is not allowed to include a second field used to indicate a configuration for UE to transmit sidelink communication based on network scheduling in the first RRC message.

Abstract: A method and apparatus are disclosed from the perspective of a first User Equipment (UE) in RRC_CONNECTED to request sidelink resources. In one embodiment, the method transmits a first RRC (Radio Resource Control) message to a network node, wherein a presence of a sidelink QoS (Quality of Service) information list in the first RRC message is optional.

Abstract: A method and device are disclosed from the perspective of a User Equipment-to-User Equipment (UE-to-UE) Relay to forward sidelink UE capability information. In one embodiment, the method includes the UE-to-UE Relay receiving a first sidelink UE capability information from a first UE. The method further includes the UE-to-UE Relay transmitting the first sidelink UE capability information of the first UE and a second sidelink UE capability information of the UE-to-UE Relay to a second UE or transmits a combined sidelink UE capability information to the second UE, wherein the combined sidelink UE capability information is derived from the first sidelink UE capability information and the second sidelink UE capability information.

Abstract: A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), if sidelink packet duplication is configured or enabled for a Sidelink Radio Bearer (SLRB), a first Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU), corresponding to a first PDCP Service Data Unit (SDU), and a duplicate of the first PDCP PDU, are transmitted. A first PDCP Sequence Number (SN) of the first PDCP PDU is set based upon one or more state variables used for sidelink transmission on the SLRB. If the sidelink packet duplication is de-configured or disabled for the SLRB, a second PDCP PDU, corresponding to a second PDCP SDU, is transmitted. Noduplicate of the second PDCP PDU is transmitted. A second PDCP SN of the second PDCP PDU is set based upon the one or more state variables used for sidelink transmission on the SLRB.

Abstract: A method and device are disclosed for radio resource allocation to support User Equipment-to-Network (UE-to-Network) relaying. The network node establishes a Radio Resource Control (RRC) connection with a remote UE via a relay UE. The network node transmits a first RRC message to the remote UE via the relay UE, wherein the first RRC message includes a Uu radio bearer configuration and a Sidelink (SL) Radio Link Control (RLC) bearer configuration associated with a data radio bearer (DRB) or a signalling radio bearer (SRB) and wherein the network node is allowed to include a first field used to indicate a configuration for UE autonomous resource selection for sidelink communication transmission in the first RRC message and the network node is not allowed to include a second field used to indicate a configuration for UE to transmit sidelink communication based on network scheduling in the first RRC message.

Abstract: A method and apparatus are disclosed from the perspective of a UE (User Equipment) to handle a sidelink buffer status report (SL BSR). In one embodiment, the method includes the UE transmitting a SL BSR to a network node, wherein a format of the SL BSR includes at least one field of buffer size associated with HARQ (Hybrid Automatic Repeat Request) feedback enabled and one field of buffer size associated with HARQ feedback disabled. The method also includes the UE receiving a sidelink grant from the network node. The method further includes the UE selecting data from a logical channel for transmission according to a HARQ feedback mode of the logical channel and whether the sidelink grant is associated with a HARQ feedback resource or not.

Abstract: 23A wireless communications device has a first security key, a second security key, and established channels. Each established channel has a corresponding security count value, and utilizes a security key. At least one of the established channels utilizes the first security key. The second security key is assigned to a new channel. A first set is then used to obtain a first value. The first set has only security count values of all the established channels that utilize the second key. The first value is at least as great as the x most significant bits (MSBx) of the greatest value in the first set. The MSBx of the initial security count value for the new channel is set equal to the first value. If the first set is empty, then the initial security count is set to zero.