Abstract: A method and device for a relay User Equipment (UE) are disclosed. In one embodiment, the relay UE establishes a first PC5 Radio Resource Control (RRC) connection with a first remote UE and establishes a second PC5 RRC connection with a second remote UE. The relay UE also transmits configurations of multiple PC5 Relay Radio Link Control (RLC) channels to the first remote UE, wherein each of the multiple PC5 Relay RLC channels is configured for forwarding data packets received from at least the second remote UE to the first remote UE. In addition, the relay UE detects a PC5 radio link failure (RLF) with the second remote UE.

Abstract: A method and device for a source remote User Equipment (UE) are disclosed. In one embodiment, the source remote UE establishes a PC5 Radio Resource Control (RRC) connection with a relay UE. The source remote UE also establishes at least one end-to-end (E2E) PC5 RRC connection with at least one target remote UE via the relay UE. The source remote UE further transmits at least one configuration of at least one PC5 Relay Radio Link Control (RLC) channel to the relay UE, wherein the at least one PC5 Relay RLC channel is used to transmit data packets for at least one target remote UE. In addition, the source remote UE detects an E2E PC5 Radio Link Failure (RLF) associated with a target remote UE among the at least one target remote UE.

Abstract: A method and device for notification message transmission. In one embodiment, a UE-to-UE (U2U) relay UE establishes a first PC5 Radio Resource Control (RRC) connection with a first remote UE and establishes one or more second PC5 RRC connections with one or more additional remote UEs so that the first remote UE can communicate with the one or more additional remote UEs via the U2U relay UE. The U2U relay UE also transmits a notification message to the first remote UE, wherein the notification message includes a sidelink indication type and information identifying a second remote UE among the one or more additional remote UEs.

Abstract: A method and device for measurement reporting are disclosed. In one embodiment, a remote User Equipment (UE) receives a UE-to-Network (U2N) Relay discovery message from a first relay UE, wherein the U2N Relay discovery message includes a User Info identity (ID) of the first relay UE, a Layer-2 ID of a second relay UE, and an ID of a serving cell of the second relay UE. Furthermore, the remote UE transmits a measurement report message to a network node, wherein the measurement report message includes a measurement result of the first relay UE, the Layer-2 ID of the second relay UE, and the ID of the serving cell of the second relay UE.

Abstract: A method and device for UE-to-Network (U2N) Relay discovery are disclosed. In one embodiment, a second relay UE receives a first U2N Relay discovery message from a first relay UE, wherein the first U2N Relay discovery message includes a User Info Identity (ID) of the first relay UE, a Layer-2 ID of a third relay UE, and an ID of a serving cell of the third relay UE. Furthermore, the second relay UE transmits a second U2N Relay discovery message to a remote UE, wherein the second U2N Relay discovery message includes a User Info ID of the second relay UE, the Layer-2 ID, and the ID of the serving cell.

Abstract: A method and device for supporting multi-hop UE-to-UE relay are disclosed. In one embodiment, the second relay UE is provided with a maximum number of hops specific for a Relay Service Code (RSC) by a network. Furthermore, the second relay UE receives a first PC5-S message from a first relay UE, wherein the first PC5-S message includes a User Info Identity (ID) of a first end UE, the RSC, and an accumulated number of hops. In addition, the second relay UE transmits or broadcasts a second PC5-S message if the accumulated number of hops plus 1 is less than the maximum number of hops, wherein the second PC5-S message includes the User Info ID of the first end UE and the RSC.

Abstract: A method and device for supporting multi-hop UE-to-Network (U2N) Relay are disclosed. In one embodiment, the second relay UE is provided with a maximum number of hops specific for a Relay Service Code (RSC) by a network. Furthermore, the second relay UE receives a first U2N Relay Discovery Announcement message from a first relay UE, wherein the first U2N Relay Discovery Announcement message includes a User Info Identity (ID) of the first relay UE, the RSC, and a first accumulated number of hops. The second relay UE also transmits or broadcasts a second U2N Relay Discovery Announcement message if the first accumulated number of hops plus 1 is less than or equal to the maximum number of hops, wherein the second U2N Relay Discovery Announcement message includes the User Info ID of the second relay UE, the RSC, and a second accumulated number of hops.

Abstract: In supporting multiple connectivity services, a remote UE establishes a PC5 unicast link with a Layer-2 UE-to-Network relay UE. Furthermore, the remote UE establishes at least two connectivity services with at least two data networks over the PC5 unicast link.

Abstract: A method and device are disclosed for Uu radio bearer to Sidelink (SL) Radio Link Control (RLC) mapping. In one embodiment, the method includes a network node transmitting a Radio Resource Control (RRC) message to a relay User Equipment (UE), wherein the RRC message includes a first information indicating a mapping which represents an association between a Uu radio bearer and a SL RLC bearer and wherein the RRC message also includes a second information identifying a remote UE associated with the mapping. The method further includes the network node transmitting an adaptation layer Protocol Data Unit (PDU) to the relay UE, wherein a header of the adaptation layer PDU includes an identity of the Uu radio bearer and a local UE identifier of the remote UE.

Abstract: A method and device for a UE-to-UE relay are disclosed. In one embodiment, the UE-to-UE relay establishes a first PC5 Radio Resource Control (RRC) connection with a first remote User Equipment (UE) and establishes a second PC5 RRC connection with a second remote UE to support communication between the first remote UE and the second remote UE via the UE-to-UE relay. The UE-to-UE relay also transmits a first RRC message to a network node to request sidelink transmission resource, wherein the first RRC message includes an identity (ID) of the first remote UE and at least one of following information: a destination ID of the second remote UE, an ID of a Sidelink (SL) Data Radio Bearer (DRB), a third ID of a PC5 quality of service (QoS) flow, and a PC5 QoS profile of the PC5 QoS flow.

Abstract: A method and device for a UE-to-UE relay are disclosed. In one embodiment, the UE-to-UE relay establishes a first PC5 Radio Resource Control (RRC) connection with a first remote User Equipment (UE) and establishes a second PC5 RRC connection with a second remote UE to support communication between the first remote UE and the second remote UE via the UE-to-UE relay. The UE-to-UE relay also transmits a first RRC message to a network node to request sidelink transmission resource, wherein the first RRC message includes an identity (ID) of the first remote UE and at least one of following information: a destination ID of the second remote UE, an ID of a Sidelink (SL) Data Radio Bearer (DRB), a third ID of a PC5 quality of service (QoS) flow, and a PC5 QoS profile of the PC5 QoS flow.

Abstract: A method and device are disclosed from the perspective of a first User Equipment (UE) to perform a PC5 unicast link establishment procedure. In one embodiment, the method includes the first UE transmitting a first PC5-S message for establishing a PC5 unicast link with a UE-to-UE Relay, wherein the PC5-S message includes a Layer-2 Identity (ID) of a second UE. The method further includes the first UE receiving a second PC5-S message from the UE-to-UE Relay, wherein the second PC5-S message is transmitted by the UE-to-UE Relay in response to reception of the first PC5-S message.

Abstract: A method and device are disclosed from the perspective of a Remote User Equipment (UE) for modifying QoS information. In one embodiment, the method includes a Remote User Equipment (UE) transmitting a first message to a Relay UE for QoS information modification, wherein the first message includes at least one QoS rule and/or at least one QoS flow description associated with a Protocol Data Unit (PDU) session.

Abstract: A method and device for supporting multi-path (MP) transmission are disclosed. In one embodiment, a remote User Equipment (UE) communicates with a network node via a direct path and an indirect path. The remote UE also connects with a relay UE via sidelink (SL) or PC5 interface to support the indirect path. In addition, the remote UE is configured with direct bearers and indirect bearers by the network node. Furthermore, the remote UE transmits a buffer status report (BSR) and a SL-BSR to the network node over the direct path, wherein the BSR includes data volume of at least one of the direct bearers and the SL-BSR includes data volume of at least one of the indirect bearers.

Abstract: A method and device for supporting multi-path (MP) transmission are disclosed. In one embodiment, a relay User Equipment (UE) connects with a network node. The relay UE also connect with a remote UE via a non-3GPP standard interface. Furthermore, the relay UE is configured with a Radio Link Control (RLC) entity associated with an indirect bearer of the remote UE by the network node. In addition, the relay UE transmits a buffer status report (BSR) to the network node, wherein the BSR includes data volume in a Packet Data Convergence Protocol (PDCP) entity and the RLC entity and wherein the PDCP entity is associated with the indirect bearer and is established in the remote UE.

Abstract: A method and device for supporting multi-path transmission or communication. In one embodiment, a User Equipment (UE) establishes a Radio Resource Control (RRC) connection with a network node. The UE also transmits a RRC message to the network node, wherein the RRC message includes a Cell Radio Network Temporary Identifier (C-RNTI) of a relay UE. Furthermore, the UE receives a RRC Reconfiguration message from the network node, wherein the RRC Reconfiguration message includes a configuration of a Data Radio Bearer (DRB) and wherein the DRB is mapped to a first Radio Link Control (RLC) entity in the UE and a second RLC entity in the relay UE. In addition, the UE transmits a data packet of the DRB to the network node via the first RLC entity and/or the second RLC entity.

Abstract: A method and device for Quality of Service (QOS) flow establishment are disclosed. A relay User Equipment (UE) establishes a PC5 unicast link with a remote UE. The relay UE also receives an identity of a PC5 QoS flow and a first PC5 5G QoS Identifier (PQI) of the PC5 QoS flow from the remote UE for adding the PC5 QoS flow, wherein the first PQI indicates end-to-end QoS requirements of the PC5 QoS flow for traffic transmission between the remote UE and a network. The relay UE further derives a second PQI for the PC5 QoS flow and a 5QI for a QoS flow according to the first PQI. In addition, the relay UE transmits a Protocol Data Unit (PDU) Session Modification Request message to the network for adding the QoS flow, wherein the PDU Session Modification Request message includes an identity of the QoS flow and the 5QI.

Abstract: A method and device for duplicate PDU discarding. In one embodiment, a User Equipment (UE) establishes a direct path and an indirect path to communicate with a network. The UE also establishes a radio bearer, wherein the radio bearer is mapped to a first Radio Link Control (RLC) entity and a second RLC entity and wherein the first RLC entity is used for communication with the network over the direct path and the second RLC entity is used for communication with the network over the indirect path. In addition, a Packet Data Convergence Protocol (PDCP) entity, which is in the UE and which is associated with the radio bearer, prevents from indicating to the first RLC entity to discard a first PDCP PDU when successful delivery of the first PDCP PDU is confirmed by the second RLC entity.

Abstract: A method and device for Quality of Service (QOS) flow establishment are disclosed. A relay User Equipment (UE) establishes a PC5 unicast link with a remote UE. The relay UE also receives an identity of a PC5 QoS flow and a first PC5 5G QoS Identifier (PQI) of the PC5 QoS flow from the remote UE for adding the PC5 QoS flow, wherein the first PQI indicates end-to-end QoS requirements of the PC5 QoS flow for traffic transmission between the remote UE and a network. The relay UE further derives a second PQI for the PC5 QoS flow and a 5QI for a QoS flow according to the first PQI. In addition, the relay UE transmits a Protocol Data Unit (PDU) Session Modification Request message to the network for adding the QoS flow, wherein the PDU Session Modification Request message includes an identity of the QoS flow and the 5QI.

Abstract: A method and device are disclosed from the perspective of a first remote User Equipment (UE). In one embodiment, the method includes the first remote UE establishing a first Sidelink (SL) Data Radio Bearer (DRB) for transmission to a second remote UE via a relay UE, wherein the first SL DRB is identified by a Radio Bearer (RB) Identity (ID). The method further includes the first remote UE ciphering a sidelink packet to be sent to the second remote UE on the first SL DRB based on at least the RB ID.