Managing multipath communications in multipath system

Abstract

A method and apparatus for managing multipath communication in a wireless communication system supporting multipath communication and relaying between a UE and a network including a base station. The UE is connected to the base station via a direct path, and wherein an indirect path between the UE and the base station comprising a relay node is to be established. The method comprises, at the relay node, sending to the UE or the base station information indicating whether the relay node supports the PC5 trigger to enter the RRCCONNECTED state. Also disclosed are a method and apparatus for managing the use of a signaling radio bearer (SRB) in a wireless communication system supporting multipath communication and relaying between a user equipment (UE) and a network comprising a base station.

Description

Technical Field

[0001] This invention generally relates to managing multipath communication in wireless communication systems that support multipath communication and relay between user equipment (UE) and a network including base stations. In examples, the use of managing a signalalling radio bearer (SRB) in a wireless communication system supporting multipath (MP) communication and relay (such as sidelink (SL) relay) between UE and base stations is also disclosed, and in particular, the use of the SRB on indirect paths to handle control plane operations in a multipath transmission system is managed upon triggering events configured in the network (e.g., gNB). Background Technology

[0002] The 3rd Generation Partnership Project (3GPP) has initiated the development of a new radio access technology known as 5G New Radio (5G NR) to respond to requirements associated with very high reliability and very low latency. 5G NR involves not only enhancements to radio access technology but also addressing a wide range of new services to be enabled by future mobile communications. Three distinct categories of use cases are defined in NR: enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC).

[0003] In 3GPP Release 16, the first version of the 5G sidelink, or New Radio (NR) sidelink, was developed as part of the 5G V2X Working Project (WI) to support advanced Vehicle-to-Everything (V2X) scenarios and commercial applications and services, in addition to supplementing previous basic security services. NR V2X addresses advanced driving use cases where vehicles are exchanging large amounts of data while adhering to low latency requirements. The NR sidelink is designed to provide three basic transport scenarios—broadcast, multicast, and unicast communication—while considering both out-of-coverage and in-network coverage deployments.

[0004] Based on NR sidelink technology, 3GPP introduced sidelink-based relay functionality as part of the 3GPP Release 17 framework. In this framework, a relay UE can provide a set of user plane (UP) and control plane (CP) data relays between a served remote UE and the network (UE-to-network relay or U2N relay) or user plane (UP) and control plane (CP) data relays between a source remote UE or a source UE and a target remote UE or a target UE (UE-to-UE relay or U2U relay).

[0005] The purpose of the sidelink relay functionality in version 17 is to extend sidelink / network coverage and improve power efficiency, while considering a wide range of applications and services, including V2X, public safety, and commercial applications and services. Some of these new scenarios require ultra-reliable low-latency (URLLC) performance to meet high-speed and high-density constraints, while also requiring some network coverage extension, which can be achieved through sidelink relay.

[0006] As defined in Release 17, this first version of the sidelink trunk functionality was primarily designed to support UE-to-network (U2N) trunking with basic functionality and limited features. To better support use cases requiring sidelink trunking, further enhancements were needed to introduce potential solutions identified during the Rel-17 study project. The subsequent 3GPP Release 18 work project, “NR Sidelink Trunk (SLR) Enhancements,” addressed several solutions for areas of enhancement required in NR sidelink trunking systems for V2X, public safety, and commercial use cases.

[0007] Multipath relay has been specified as a solution in version 18 NR SLR enhanced WI, in which remote UEs connect to the network via a direct path (e.g., a link between the UE and the network's base station (also called a gNB), referred to as a Uu link) and an indirect path (e.g., a path between the remote UE and the network's base station (also called a gNB) that includes a relay UE, where the link between the remote UE and the relay UE is referred to as a PC5 link, so the path includes both a PC5 link and a Uu link), and has the potential to improve the reliability, robustness and throughput of communications.

[0008] This multipath relay solution is designed to provide high uplink (UL) data rates for applications requiring high UL data rates on 5G terminals, especially at cell edges. Furthermore, if one path is experiencing degraded channel conditions, multipath relay can improve the reliability and stability of the service provided while reducing latency.

[0009] A remote UE configured for multipath relay can transmit data via multiple paths. The transmitted data is associated with radio bearers configured by the network. To improve reliability and / or throughput, data can be transmitted via multiple paths, and therefore, a radio bearer can be mapped to multiple configured paths. This radio bearer has been considered in the RAN2 meeting for the version 18 multipath relay scenario and has been named "MP split bearer" or "MP bearer". An MP bearer, or end-to-end (E2E) radio bearer (RB), can be a signaling radio bearer (SRB) for control data or a data radio bearer (DRB) for user data. An E2E RB can be assigned to a single path (e.g., a direct path or an indirect path), and therefore it is named a non-split MP radio bearer or MP non-split bearer. Since a remote UE has two paths in a multipath transmission system, an E2E RB can be assigned to both paths, and therefore it is called an MP split radio bearer or MP split bearer.

[0010] As specified in SLR WI RP-221262 of version 18, the remote UE is connected to the same gNB via a direct path and via an indirect path. Therefore, the remote UE is configured for multipathing within the same gNB (within the gNB). The configuration is transmitted to the remote UE via one of the paths (e.g., the direct path or the indirect path) using a signaling radio bearer (SRB). In the following description, SRB may refer to SRB1 or SRB2. SRB1 is more dedicated to carrying RRC messages, while SRB2 is intended for NAS messages. SRB2 provides a lower priority than SRB1.

[0011] In Release 18 SLR Work Item RP-221262, it was decided that SRB1 / 2 would be primarily transmitted on the direct path. Different configuration types for SRB1 / 2 are allowed in multipath transport systems: non-separate configuration type and separate configuration type (with or without duplicates). Typically, non-separate SRB1 / 2 is only allowed on the direct path; therefore, there is no control plane on the indirect path. However, if duplicates are activated, a separate SRB1 / 2 configuration can allow duplicate RRC PDUs on both the direct and indirect paths. Furthermore, a non-duplicate separate SRB1 / 2 configuration may only have RRC PDUs on the primary path (primarily considered the direct path in a multipath configuration system, where, for example, the indirect path is considered the secondary path in this case)).

[0012] However, there are some use cases where SRB1 / 2 needs to be sent via the indirect path. For example, a direct path failure can cause an interruption in signaling flow, and in cases where signaling cannot be exchanged between the remote UE and the gNB, it is impossible to send a failure report. Furthermore, any brief inactivity on the direct path (such as a direct path change or release) can also cause a break in signaling flow between the remote UE and the gNB. In such cases, SRB1 is required on the enabled second (or active) path (i.e., the indirect path), and more generally, SRBs are needed to ensure service continuity.

[0013] In another example, a remote UE can select a relay UE in any RRC state for use in the indirect path, and thus for creating a multipath transmission system. Therefore, a relay UE in the IDLE / INACTIVE RRC state can be assigned to the indirect path. When a relay UE is in a non-connected RRC state (e.g., IDLE / INACTIVE RRC state), data cannot be transmitted between the remote UE and the gNB on the indirect path. A dedicated PC5-RRC message was introduced in version 18 to address this issue and acts as a trigger to switch the relay UE to the CONNECTED RRC state, enabling the use of the indirect path; however, this new trigger is not backward compatible with legacy relay UEs released according to previous versions prior to version 18. Therefore, relay UEs of version 17 are incompatible and may not be aware of the new PC5-RRC message.

[0014] Therefore, it is desirable to provide new mechanisms that help control the use of SRBs on direct and / or indirect paths used for multipath communication to avoid or minimize signaling interruptions or disconnections. Summary of the Invention

[0015] According to one aspect of the present invention, a method for managing multipath communication in a wireless communication system is provided, the wireless communication system supporting multipath communication and relay between a user equipment (UE) and a network including a base station, wherein the UE is connected to the base station via a direct path, and wherein an indirect path including a relay node is to be established between the UE and the base station, the method comprising, at the relay node: sending information to the UE or the base station indicating that the relay node is a version 18 relay node or a relay node of a higher version than version 18. This information may include information indicating whether the relay node can support PC5 triggering to enter an RRC connection state.

[0016] According to another aspect of the present invention, a method is provided for managing the use of a signaling radio bearer (SRB) in a wireless communication system that supports multipath communication and relay between a user equipment (UE) and a network including a base station. The method at the UE includes: activating the SRB on a first path between the UE and the base station; receiving from the base station the configuration information for configuring the SRB on a second path between the UE and the base station, the configuration information including the trigger event information indicating one or more trigger events for triggering the use of the SRB on the second path; and, after determining that one or more of the trigger events has occurred, using the second path to carry signaling data via the SRB, wherein the first path is one of a direct path between the UE and the base station and an indirect path between the UE and the base station including a relay node, and the second path is one of the direct path and the indirect path.

[0017] According to another aspect of the present invention, a method is provided for managing the use of a signaling radio bearer (SRB) in a wireless communication system that supports multipath communication and relay between a user equipment (UE) and a network including a base station. The method at the base station includes: sending configuration information to the UE for configuring the SRB on a first path between the UE and the base station; sending configuration information to the UE for configuring the SRB on a second path between the UE and the base station, the configuration information including trigger event information indicating one or more triggering events for triggering the use of the SRB on the second path; and receiving signaling data from the UE via the SRB using the second path, wherein the first path is one of a direct path between the UE and the base station and an indirect path between the UE and the base station including a relay node, and the second path is one of a direct path and an indirect path.

[0018] According to another aspect of the invention, an apparatus for a UE is provided as described in claim 44 of the appended claims.

[0019] According to another aspect of the invention, an apparatus for a base station is provided as described in claim 45 of the appended claims.

[0020] The configuration of a remote UE with a list of triggering events allows the remote UE to control the use of SRBs on a second path (which can be a direct or indirect path) for specific purposes. For example, if the first path is a direct path configured with non-separate SRBs or non-repeating separate SRBs, the remote UE can use the indirect path after a triggering event occurs for signaling data (e.g., RRC messages) via or through the SRB, without needing to reconfigure or re-establish the first path (depending on the triggering event). Furthermore, the base station may not need to reconfigure the SRBs on the second path at each triggering event because the remote UE can configure and control the use of the SRBs based on one or more triggering events and information included in the configuration information provided prior to any triggering event.

[0021] For backward compatibility issues (e.g., when the relay node is not identified as a relay node of 3GPP version 18 or later, such as when the relay node is a relay node of version 17), an SRB (e.g., SRB1) can be assigned to a second path (in this case, an indirect path) in response to a backward compatibility event determined by the remote UE, and the relay UE can be triggered by an RRCConfigurationComplete message sent by the remote UE via the configured indirect path or other version 17 procedures. Therefore, even when the relay node is not a relay node of 3GPP version 18 or later, the relay node can still be triggered by the remote UE to transition from a disconnected RRC state to a connected RRC state.

[0022] The configuration may further include PDCP information indicating the SRB type to be used for the SRB when or after the occurrence of one or more triggering events is determined. If the activated SRB on the first path is a non-split bearer type SRB or a non-repeating split bearer type SRB, the remote UE may determine, based on the PDCP information, whether to change the type of the SRB to be configured on the second path after the occurrence of one or more triggering events is determined. The PDCP information may include at least one of the following: PDCP repetition configuration information for configuring the UE to activate PDCP repetition after the occurrence of one or more triggering events is determined; PDCP switching configuration information for configuring the UE to switch the SRB to the second path after the occurrence of one or more triggering events is determined; and PDCP configuration information for indicating to the UE the SRB type to be used for the SRB after the configuration of the SRB on the second path has been completed, or when or after the occurrence of one or more triggering events is determined. PDCP information enables the base station to control the SRB configuration at or after a triggering event, and allows the remote UE to know whether the SRB configuration will be applied at the triggering event and maintained thereafter, or whether it will only be applied at the triggering event and some other SRB configuration (which could be the initial configuration applied on the first path or a new configuration) will be applied after the triggering event. This provides a flexible solution for configuring SRBs for multipath communication.

[0023] Other exemplary features of the invention are described in the other independent and dependent claims.

[0024] Any feature of one aspect of the invention may be applied to other aspects of the invention in any suitable combination. In particular, a method aspect may be applied to an apparatus / device / unit aspect, and vice versa.

[0025] Furthermore, features implemented in hardware can be implemented in software, and vice versa. Any references to software features and hardware features herein should be interpreted accordingly. For example, according to other aspects of the invention, a computer program comprising instructions that, when executed by one or more processing units, cause one or more processing units to perform any of the methods described above or examples are provided, and a computer-readable storage medium carrying the computer program is provided. Attached Figure Description

[0026] Different aspects of the invention will now be described by way of example only and with reference to the following figures, in which:

[0027] Figure 1aThis is a schematic diagram illustrating an example wireless communication system that can implement the present invention according to one or more embodiments;

[0028] Figure 1b This is a schematic diagram illustrating a typical 5G Proximity-based Services (ProSe) relay reference architecture;

[0029] Figure 2 This is a schematic diagram illustrating some of the user plane and control plane stacks of the protocol layers involved in side-link relay operations for UE-to-network (U2N) based relays;

[0030] Figure 3 This is a schematic simplified diagram of an example message flow illustrating the use of SRB1 on an indirect path when the direct path is inactive, according to one or more embodiments of the present invention, for managing the use of SRB in a wireless communication system that supports multipath communication and relay.

[0031] Figure 4 This is a schematic simplified diagram of an example message flow illustrating the use of SRB1 on an indirect path in the event of a direct path failure, according to one or more embodiments of the present invention, for managing the use of SRB in a wireless communication system supporting multipath communication and relay.

[0032] Figure 5 This is a schematic simplified diagram illustrating an example message flow for managing the use of SRB in a wireless communication system supporting multipath communication and relay, according to one or more embodiments of the present invention, in an example use case of backward compatibility with the use of SRB1 on indirect paths.

[0033] Figure 6 This is a schematic block diagram of an example wireless communication device according to one or more embodiments of the present invention;

[0034] Figure 7 This is a simplified flowchart of a method performed at a UE according to one or more embodiments of the present invention;

[0035] Figure 8 This is a simplified flowchart of a method performed at a base station according to one or more embodiments of the present invention; and

[0036] Figure 9 This is a simplified flowchart of a method performed at a relay node according to one or more embodiments of the present invention. Detailed Implementation

[0037] Figure 1aThis is a schematic diagram illustrating an example wireless communication system 100 that can implement the present invention according to one or more embodiments. The wireless communication system 100 is a communication system capable of supporting sidelink relay and multipath communication or multipath relay, and illustrates a sidelink relay arrangement or system (or network) including multiple nodes, such that one or more relay user equipments (UEs) serving one or more remote user equipments (UEs).

[0038] In the following description, reference is made to a wireless communication system 100 capable of supporting sidelink (SL) relay, wherein the path between a remote UE and a base station includes a sidelink connection (also referred to as a PC5 link) between the remote UE and a relay node (also referred to as a relay UE) and a network connection (also referred to as a Uu link) between the relay UE and the base station. However, the present invention is not intended to be limited to PC5 links between remote UEs and relay UEs, and can be applied to relay configurations where the link between a remote UE and a relay UE is via another type of connection (e.g., a non-3GPP connection) (such as WiFi or Bluetooth).

[0039] Even in the context of V2X networks where sidelink relay is most likely considered, this invention is not intended to be limited to UE nodes in or part of a vehicle. Each UE node (relay or remote) can be a wireless communication device located in or part of a vehicle or roadside unit (RSU), or a wireless communication device for a vulnerable road user (VRU) (e.g., a mobile or portable communication device for a pedestrian or cyclist, such as a smartphone, PDA, laptop computer, or similar device). Although embodiments and examples of embodiments of the invention will be described with reference to 5G NR networks in the following description, it will be understood that the invention is not intended to be limited to 5G NR systems and can be used in any wireless communication system that supports sidelink (or peer-to-peer) relay communication and multipath communication.

[0040] refer to Figure 1a UE node 110 is served by network node 106 and can operate as a relay UE node to relay data between UE node 113 (referred to as remote UE node) and network node 106, thereby performing UE-to-network (U2N) relay. In the example where network node 106 is part of a cellular network, relay UE 110 is served by the cell controlled by network node 106.

[0041] Network nodes 106 and 107 can be base stations for wireless networks, such as fifth-generation (5G) New Radio (NR) networks or Long Term Evolution (LTE) networks. For clarity, Figure 1aOnly the base station of the wireless network is shown. For a 5G NR network, network nodes 106 and 107 are referred to as gNodeB or gNB. gNB 106 is separated into a centralized unit (gNB-CU) 104 and multiple distributed units (gNB-DU), such as gNB-DU1 101 and gNB-DU2 102, etc. gNB 107 is a non-separated base station in the sense that the functions of the centralized unit (gNB-CU) and the distributed units (gNB-DU) are combined in one entity. In one example, the centralized unit gNB-CU (e.g., gNB-CU 104 and gNB-CU 107) provides support for higher layers such as SDAP, PDCP, and RRC layers, while the distributed units gNB-DU (e.g., gNB-DU 101, 102, and gNB-DU 107) provide support for lower layers such as MAC and PHY. gNB-DU can serve different cells. The gNB-CU connects to the gNB-DU via an F1 interface (e.g., F1 interfaces 101a and 102a). The gNB-CU can exchange different F1AP messages with the gNB-DU via the F1 interface. For example, the gNB-CU can configure the UE context at the selected gNB-DU using the UE context management procedure specified in Section 8.3 of 3GPP TS 38.473. Furthermore, as specified in Section 8.4 of TS 38.473, the gNB-CU can send RRC messages for the UE to the gNB-DU in an RRCMESSAGE TRANSFER container, which will then be forwarded to the UE.

[0042] In the following text, relay UE nodes will also be referred to as relay nodes or relay UEs, remote UE nodes will also be referred to as remote UEs, and network nodes will be referred to as base stations or gNBs.

[0043] exist Figure 1aIn the example shown, in a UE-to-network (or U2N) relay scenario where UE 110 operates as a UE-to-network (or U2N) relay UE, UE-to-network relay UE 110 connects UE 113, which operates as a remote UE, to gNB-DU1 101. Remote UE 113 connects to relay UE 110 via or through link 113a. Link 113a may be referred to as a hop, link, connection, interface, or leg 113a. Link 113a can be a sidelink (PC5 link) or a non-3GPP link (ideal UE-UE connection). Link 113a is used for relay services of remote UE 113 and non-relay services specific to relay UE 110, i.e., for direct communication between relay UE 110 and remote UE 113. Therefore, the remote UE 113 is connected to the gNB-DU1 101 via a relay UE 110 with PC5 / non-3GPP hop 113a and Uu hop 110a.

[0044] For uplink communication, remote UE 113 is the source node (or the transmitter node for transmitting data), and gNB-DU1 101 is the destination or target node (or the receiver node for receiving data) for establishing a sidelink relay connection between remote UE 113 and gNB-DU1 101 using PC5 / non-3GPP hop 113a and second Uu hop 110a. For downlink communication, remote UE 113 is the destination or target node (or the receiver node), and gNB-DU1 101 is the source node (or the transmitter node).

[0045] Remote UE 113 can connect to gNB 106 via multiple paths in a multipath configuration. For example, remote UE 113 can connect to gNB-DU1 101 via relay UE 110 and can also connect directly to gNB-DU2 102. Therefore, the remote UE connects to gNB 106 via an indirect path (113a+110a) and via a direct path 113b.

[0046] The gNB-CU 104 can configure end-to-end multipath radio bearers (E2E RBs) between a remote UE and the network using different configuration types. An E2E RB can be assigned to a single path (e.g., a direct path or an indirect path), and in this case, the E2E RB type is named non-separated MP radio bearer or MP non-separated bearer or non-separated bearer. Since the remote UE has two paths in the multipath transmission system, an E2E RB can be assigned to both paths; thus, in this case, the E2E RB type is called MP separated radio bearer or MP separated bearer or separated bearer.

[0047] For MP split bearers, PDCP repetition is supported. When repetition is activated, the MP split bearer is called a split bearer with repetition, and RBs are activated on both paths. However, when repetition is deactivated, the MP split bearer is called a split bearer without repetition, and it is activated only on one path, which is usually a direct path. Different configuration types for MP radio bearers can be applied to signaling radio bearers (SRBs) and data radio bearers (DRBs).

[0048] Signaling radio bearers, or SRBs, are defined as radio bearers (RBs) used solely for the transmission of signaling (e.g., signaling data) between a remote UE and the network (such as for the transmission of RRC and NAS messages). SRB separation is supported only for SRB1 and SRB2 types in multipathing. Referring to TS 38.331, SRB1 and SRB2 are defined as follows:

[0049] - SRB1 is used for RRC messages (which may include backed NAS messages) and for NAS messages before SRB2 is established, all of which use the DCCH logical channel;

[0050] - SRB2 is used for NAS messages and RRC messages that include recorded measurement information, all of which use the DCCH logical channel.

[0051] SRB2 has a lower priority than SRB1 and can be configured by the network after AS security is activated.

[0052] After SRB1 is configured for the UE, the UE can send NAS messages to the core network. These NAS messages are encapsulated in RRC messages to the gNB via or through SRB1 and are subsequently sent to the core network by the gNB. For example, a NAS registration request is encapsulated in an RRC configuration completion message. After SRB2 is established, NAS messages are sent on SRB2.

[0053] According to SLR working item RP-221262 of version 18, two multipath scenarios are supported. The link between the relay and the remote UE can be a PC5 link (Scenario 1) or a non-3GPP link (Scenario 2).

[0054] According to the RAN2 working group, six use cases were designated for path management in Scenario 1 for further study in Release 18. The use cases published in R2-2210804, Clause 8.9.4, are divided among path addition for indirect and direct paths (cases A and B, respectively), path release for indirect and direct paths (cases C and D, respectively), and path modification for direct and indirect paths (cases E and G, respectively). Two use cases, indirect path addition (case B) and indirect path release (case D), are supported for Scenario 2.

[0055] In the first example, remote UE 113 can connect to the same gNB-DU1 101 via a direct path (e.g., via Uu link 113b) and an indirect path via relay UE 110 (e.g., via PC5 link 113a and Uu link 110a). Remote UE 113 can make a direct path change (case E) to connect to a different gNB-DU2 102 within the same gNB 106 (e.g., changing from link 113b to...). Figure 1a (Link 113c is shown in dashed lines). Direct path changes can include changes to cells within the same gNB-DU or changes to gNB-DUs within the same gNB.

[0056] In the second example, a remote UE 113 connected to gNB-DU1 101 (113a+110a, 113b) in a multipath can hand over its direct path 113b by connecting to a second gNB 107 via direct path 113d.

[0057] The handover to gNB 107 can serve as a path switching between gNBs. Figure 1a (Not shown in the diagram) The remote UE 113 connected to gNB 106 can switch from the direct path 113b to an indirect path, in which a relay UE connects to gNB 107. Therefore, the remote UE 113 can have a multipath configuration with two indirect paths, in which a first relay 110 connects the remote UE to gNB 106, and a second relay UE connects the remote UE to gNB 107.

[0058] Figure 1b This is a schematic diagram illustrating a typical 5G Proximity-Based Service (ProSe) relay reference architecture.

[0059] Remote UEs and relay UEs are attached to the core network through their serving gNB, which is part of NG-RAN. Figure 1bThis diagram illustrates a typical 5G Proximity-Based Serving (ProSe) relay reference architecture and shows the different connections between core network entities of the 5G Core (5GC), such as Access and Mobility Management Function (AMF) entities, Session Management Function (SMF) entities, User Plane Function (UPF) entities, UEs (5G ProSe Remote and 5G ProSe Relay), and NG-RAN (i.e., base stations or gNBs). The 5G ProSe Remote UE 130 and the 5G ProSe Relay 120 can be served by the same or different PLMNs (Public Land Mobile Networks). If the 5G Remote UE and the 5G ProSe Relay serve different PLMNs, the NG-RAN is shared by the serving PLMN.

[0060] To set up relay services between the first node (remote UE) and the second node (gNB or remote UE), a sidelink relay architecture can be used according to 3GPP TR 38.836. The user plane architecture or protocol stack is... Figure 2 The diagram illustrates and represents a sidelink trunk adaptation layer, known as SRAP, which is introduced between the PDCP and RLC layers at the end node and above the RLC layer in the trunk UE. This architecture was first documented in TR 38.836 and finally refined in 3GPP TS 38.300, while the SRAP layer is defined in 3GPP TS 38.351.

[0061] Figure 2 The architecture shown illustrates a side-link trunk architecture 200 for a UE-to-network trunking scenario. As illustrated in the UE-to-network trunking scenario... Figure 2 As shown, a remote UE (such as remote UE 113) has a PC5 SRAP layer 201 between its Uu PDCP layer and its PC5 RLC layer. Similarly, a gNB (such as gNB 106) has a Uu SRAP layer 204 between its Uu PDCP layer and its Uu RLC layer.

[0062] Such as scenarios related to UE to network relay. Figure 2 As shown, at the relay UE (such as relay UE 110), there are two SRAP layers to engage with PC5 hop 113a and Uu hop 110a: PC5 SRAP layer 202 is connected to PC5 SRAP 201 of remote UE 113 via PC5 hop 113a; and Uu SRAP layer or entity 203 is connected to UuSRAP layer 204 at gNB side 106 via Uu link 110a. Remote UE 113 establishes end-to-end (E2E) radio bearers 205 with gNB 106. These radio bearers can be signaling radio bearers (SRBs) or data radio bearers (DRBs). Figure 2 An E2E Uu DRB between the SDAP layer at remote UE 113 and gNB 106 is illustrated by way of example. An E2E SRB can also be considered between the Uu RRC layer at remote UE 113 and gNB 106.

[0063] The UE receives data or packets (service data or signaling) from the remote UE 113 (at PC5 hop 113a) in the uplink direction via or through the ingress PC5 relay RLC channel 206 (via PC5-RLC layer), and transmits the packet to the Uu SRAP entity 203 of the same relay UE 110.

[0064] The Uu SRAP 203 entity maps the corresponding ingress PC5 relay RLC channel 206 to the egress Uu relay RLC channels 207a and / or 207b at the Uu link 110a. Therefore, the uplink requires a mapping table, which is configured by gNB 106 at the Uu SRAP entity 203 of the relay UE 110.

[0065] The mapping table takes as input the identifier of the remote UE 113 (e.g., L2-ID), the identifier of the E2E radio bearer 205 (e.g., E2E Uu DRB / SRB 205 ID), and the identifier of the ingress PC5 relay RLC channel (or bearer) 206, and identifies the egress Uu relay RLC bearer ID that maps the E2E radio bearer. For example, the UE E2E bearer ID and the remote UE ID can be obtained from the header of a data packet received at UuSRAP entity 203 via PC5-SRAP entity 202. Table 1 below shows an example of an entry in an uplink mapping table with one entry configured at UuSRAP entity 203. It should be understood that the mapping table will be configured such that it has entries for each remote UE connected to the relay UE.

[0066]

[0067] Table 1

[0068] On the Uu side or at link 110a, different radio bearers of the same remote UE or different remote UEs can undergo N:1 mapping and data multiplexing on UuRLC channels 207a and 207b.

[0069] In the downlink direction, data or packets transmitted from gNB 106 reach relay UE 110 via Uu link 110a. The UE receives data or packets (service data or signaling) from gNB 106 via or through ingress Uu relay RLC channels 207a and 207b (through the Uu RLC layer) to the Uu SRAP layer 203 of network relay UE 110, and transmits the packets to the PC5 SRAP entity 202 of the same relay UE 110. These ingress Uu relay RLC channels 207a and 207b are mapped at the PC5 SRAP entity 202 of relay UE 110 to the egress PC5 relay RLC channel 206 at PC5 hop 113a. Therefore, a mapping table is required for the downlink, and this mapping table is configured by gNB 106 at the PC5 SRAP entity 202 of relay UE 110. The mapping table requires the remote UE 113 L2-ID, the end-to-end radio bearer 205 ID, and the ingress Uu relay RLC channel (or bearer) IDs 207a and 207b at its input, and the egress PC5 relay RLC channel (or bearer) ID 206 identifying PC5 hop 113a. The end-to-end radio bearer 205 is then mapped to the egress PC5 relay RLC channel 206 at PC5 hop 113a. For example, the UE E2E bearer ID and the remote UE ID can be obtained from the header of a packet received at PC5SRAP entity 202 via Uu SRAP entity 203. Table 2 below shows an example of a downlink mapping table with one entry configured at PC5SRAP entity 202. It should be understood that the mapping table will be configured such that it has entries for each remote UE connected to the relay UE.

[0070]

[0071] Table 2

[0072] As mentioned in 3GPP TS 38.351, each SRAP entity has a transmit portion and a receive portion. Across PC5 interface 113a, the transmit portion of PC5 SRAP entity 201 at remote UE 113 has a corresponding receive portion at PC5 SRAP entity 202 at network relay UE 110, and vice versa. Across Uu interface 110a, the transmit portion of Uu SRAP entity 203 at network relay UE 110 has a corresponding receive portion at Uu SRAP entity 204 at gNB 106, and vice versa. In summary, the transmit portion of each SRAP entity at network relay UE 110 receives data packets with their SRAP headers from its corresponding receive portion (the receive portion of SRAP entity 202 forwards data to the transmit portion of SRAP entity 203, and vice versa). Each SRAP entity's transport portion possesses a mapping table configured by gNB 106, which allows identification of the egress RLC channel (at the Uu or PC5 link) based on the ingress RLC channel of the received data packet and the UE and bearer ID carried in the SRAP header. We can note that specific mapping rules can be applied to SRB0 and SRB1 as specified in TS38.351 and TS38.331.

[0073] In a multipath scenario with one indirect path and one direct path, remote UE 113 and gNB 106 can communicate with each other through these two paths. Thus, each node has two protocol stacks: one for the indirect path as described above, and one for the direct path. Separation between the direct path and / or indirect path is performed at the PDCP layer of each node. For the direct path, in the downlink direction, data or packets transmitted from gNB 106 via the direct path reach remote UE 113 via the ingress Uu direct path RLC channel 208 of Uu link 113b. On the other hand, in the uplink direction, data or packets transmitted from remote UE 113 via the direct path reach gNB 106 via the ingress Uu direct path RLC channel 208 of Uu link 113b.

[0074] In a multipath transmission system (e.g., when configuring multipath communication), the E2E radio bearer between remote UE 113 and gNB 106 can have different configuration types. gNB 106 can configure E2E RB 205 as a non-separated RB, thus 205 can be assigned to the direct path via link 113c or to the indirect path via links 113a+110a. In this case, the non-separated SRB is activated on a single path within the multipath transmission system. The SRB may or may not be configured on the indirect path. gNB can use E2E SRB1 / 2 to configure the SRAP layer mapping table of the U2N relay UE (e.g., 110) for later use. For example, the mapping of SRB1 / 2 can be (pre-)configured (e.g., a mapping table with SRB1 / 2 can be pre-configured at the relay UE), thus there is a (pre-)configured ingress PC5 / Uu RLC channel mapped to E2E SRB1 / 2, which can be applied by default by the relay UE 110. Otherwise, when configuring multipath communication in a multipath configuration system, the gNB can configure E2E SRB1 / 2 on the relay UE of the indirect path.

[0075] E2E RB 205 can also be configured as a separate bearer by gNB 106, and thus it is assigned to both paths in a multipath transmission system.

[0076] Split bearers can support repetition; therefore, in this case, flows are activated on both the direct and indirect paths (e.g., the direct and indirect paths are used to carry data (services or signaling) between remote UE 113 and gNB 106 via or through the split radio bearer). For example, for an E2E split SRB in 205, signaling flows will be exchanged between remote UE 113 and gNB 106 on both paths. This configuration is called a split bearer with repetition. When repetition is deactivated on the split bearer, flows are primarily activated on the direct path. For example, for an E2E split SRB without repetition in 205, signaling data will be exchanged primarily via the direct path between the remote UE and gNB 106. No data flows can be transmitted on the indirect path.

[0077] The gNB 106 can be configured with E2E SRB1 and E2E SRB2 for multipaths to access its remote UE 113. The bearer type can be a non-split SRB on the direct path or a split SRB on both paths. The split SRB can be configured with or without duplicates.

[0078] When SRB1 (or SRB2) is configured as a non-separate bearer or a non-repeating separate bearer, SRB1 (or SRB2) is active only on one path (primarily the direct path). No SRB1 (or SRB2) can be active on indirect paths.

[0079] However, there are some use cases where RRC messages are required on indirect paths.

[0080] In the first example, a change in the direct path may cause the current direct path to be inactive in the multipath transport system until a new direct path is established. On the other hand, the direct path is suspended, so if an SRB is activated on the direct path, no SRB1 (or SRB2) is available to exchange signaling flows between the remote UE 113 and gNB 106.

[0081] In the second example, a direct path release or failure may shut down the signaling flow at the direct path. A remote UE113 configured with non-split SRB1 / 2 or non-repeating split SRB1 / 2 (where the SRB is active on the direct path) cannot exchange signaling messages with the network; therefore, the control plane is affected. Figure 2 The multipath protocol stack represented in the code is no longer in use.

[0082] In the third example, remote UE 113 can connect to a relay UE (such as relay UE 110) in any RRC state. To trigger a relay UE in a non-connected RRC state (e.g., RRC_INACTIVE / IDLE state) to enter the CONNECTED state, a new PC5-RRC message was introduced in version 18, which is sent by remote UE 113 to relay UE 110 for multipathing. However, a relay UE in version 17 cannot be triggered using the new PC5-RRC message in version 18; therefore, this version 18 solution for triggering a relay UE to enter the RRC_CONNECTED state is not backward compatible. To wake up a relay UE in version 17, as specified in version 17, conventional methods such as sending an RRCReconfigurationComplete message should be used. In order for remote UE 113 to send the RRC message to relay UE 110, the RRC message should be sent by remote UE 113 toward the indirect path. Therefore, signaling bearer SRB1 also needs to be configured on the indirect path.

[0083] Figures 3 to 5This means that the aforementioned problem revealed in the previous example is solved by allocating SRBs (e.g., SRB1 / 2) to indirect paths on demand. In other words, it controls the use of indirect paths carrying signaling (e.g., signaling data) via or through SRBs (e.g., SRB1 / 2) on demand. Figure 3 and Figure 4 The message flow is compatible with connections between relay UEs and remote UEs via PC5 or non-3GPP links.

[0084] In the following description, reference is made to: activating an SRB on a direct path between a remote UE and a gNB, and, after detecting or determining that a triggering event has occurred, using an indirect path between the remote UE and the gNB to carry signaling data via the SRB. However, the present invention is not intended to be limited to changing the configuration or mapping of the SRB from a direct path to an indirect path. The present invention can be applied to situations where an SRB is activated on an indirect path between a remote UE and a gNB, and, after detecting or determining that a triggering event has occurred, signaling data is carried via the SRB using either a direct path or a second indirect path between the remote UE and the gNB. In other words, the present invention can also be applied to changing the configuration or mapping of the SRB from an indirect path to a direct path or a second indirect path. Therefore, an SRB can be activated, allocated, or configured on a first path between the UE and the base station, wherein the first path can be one of a direct path and an indirect path for MP communication, and, after detecting or determining that a triggering event has occurred, a second path can be used to carry signaling data via the SRB, wherein the second path is one of a direct path and an indirect path for MP communication.

[0085] Now for reference Figure 3 It illustrates an embodiment of the invention for managing SRBs in wireless communication systems that support multipath communication and relay (such as...). Figure 1a The example message flow illustrates the use of SRB1 in wireless communication systems (such as those shown) (particularly for managing the use of SRB1 on the second path when the first path is inactive in a multipath transmission system). By way of example, the following description is for the case where the first path is a direct path and the second path is an indirect path (between the UE and the network via a relay node). It should be understood that the following description can also be applied to cases where the first path is an indirect path and the second path is either a direct path or an indirect path. Figure 3The remote UE 113 can connect to the serving or source gNB 106 (e.g., serving or source gNB-DU1 101) via a first path or direct path (e.g., including Uu link 113b) and via a second path or indirect path (e.g., including PC5 link 113a and Uu link 110a) through relay UE 110. The relay UE 110 can be used as a U2N relay UE for relaying data between the remote UE 113 and the source gNB-DU1 101. The messages or call flows in 300 represent different exchange messages between the remote UE 113, the serving relay UE 110, the serving gNB 106, and the target gNB 107 (in the case of inter-gNB handover).

[0086] Figure 3 The message flow in the document considers the issue of direct path inactivity. By way of example rather than limitation, direct path inactivity can cover use cases of direct path change, direct path release, direct path deactivation, and inter-gNB handover. gNB106 can configure remote UE 113 to perform direct path release, direct path change, or inter-gNB handover. Furthermore, gNB106 can decide to deactivate direct paths in a multipath transmission system (e.g., if link quality deteriorates) and rely on the remaining paths to maintain connectivity with the network.

[0087] Indirect path inactivity can refer to previous use cases, such as path change, path release, path deactivation, or relay UE (re)selection or handover.

[0088] In the first example of direct path release, link 113b connecting remote UE 113 to gNB 106 is released, so remote UE 113 maintains its connection to the network via an indirect path through relay UE 110.

[0089] In the second example of a direct path change, gNB 106 can decide to switch the direct path to another cell or another gNB-DU within the same gNB. Figure 1a An example of an inter-DU path change is illustrated. Remote UE 113 can perform a direct path change from a direct path including Uu link 113b (connecting remote UE 113 to source gNB-DU1 101) to a direct path including Uu link 113c (connecting remote UE 113 to target gNB-DU2 102). During the direct path handover from source gNB-DU1 101 to target gNB-DU2 102, the direct path is suspended for signaling and data flow.

[0090] In the third example of direct path handover between gNBs, gNB 106 can configure a remote UE to hand over direct path 113b. Therefore, a remote UE 113 connected to gNB 106 can hand over to a direct path such as... Figure 1a The gNB 107 is shown. When the remote UE is in a multipath configuration, the gNB 106 can choose to hand over the direct link 113b while maintaining the remote UE 113's indirect connection to the source gNB 106 via the relay UE 110. Then, the gNB 106 releases the direct link 113b, and the gNB 107 adds a new direct link 113d. During the handover, the direct path is suspended for signaling and data flow.

[0091] In the fourth example, gNB 106 can decide to suspend any path in the multipath transmission system by deactivating the path. gNB 106 can choose to deactivate either the direct path 113b or the indirect path (113a+110a) that connects the remote UE 113 to the network. If the direct path 113b is suspended, the remote UE 113 maintains its connection to the network via the indirect path.

[0092] Figure 3 The message flow can provide a solution for controlling or managing the use of SRBs for the aforementioned examples of inactivity on direct paths.

[0093] The remote UE 113 can receive a multipath configuration from the gNB 106 in message 301a. By way of example, but not limited to, the multipath configuration may include a direct path 113b and an indirect path (113a+110a) for connecting to the gNB-DU1 101 (e.g., ...). Figure 1a The configuration information is shown below. The remote UE 113 can apply multipath configuration and can respond with configuration complete in 301b. For example, the remote UE 113 can apply multipath configuration to configure or set the remote UE 113 to communicate data via or through the configured radio bearers (SRB, DRB) using direct path 113b and indirect path (113a+110a). Specifically, and Figure 3In the example shown, the multipath configuration from gNB 106 configures remote UE 113 to activate or set an SRB at least on direct path 113b. Whether an indirect path is used at this time will depend on the type of SRB and whether separate SRB duplication is activated. Then, remote UE 113 can communicate with gNB 106 by using both paths as shown in 302 to transmit uplink (UL) data carried by a radio bearer and receive downlink (DL) data carried by a radio bearer. The multipath configuration in message 301a may also include a list of triggering events or one or more triggering events related to direct path inactivity issues.

[0094] In the example, the multipath configuration included in message 301a sent to remote UE 113 can be inserted into the RRCReconfiguration message defined in TS38.331. The RRCReconfiguration message can include the information element described below (referred to as MP-SRB-PathSwitchConfig-r18). This IE can be added to either the radiobearerconfig IE or the PDCP-config IE included in the RRCReconfiguration message.

[0095] According to one example, the configuration information for the information element MP-SRB-PathSwitchConfig-r18 used to configure SRB may include all or some of the following information:

[0096] - A list of triggering events, including one or more of the following related to path inactivity: direct path change, direct path release, direct path deactivation, direct path handover, relay (re)selection of a relay node if the first path is an indirect path, and relay handover of a relay node if the first path is an indirect path. Other triggering events related to path inactivity can be added to the enumeration list.

[0097] - PDCP-duplication: This element indicates that a remote UE will activate PDCP duplication when a triggering event occurs. gNB 106 can configure a remote UE to activate PDCP duplication when a triggering event occurs. Duplication can be activated if the SRB is initially configured as a non-duplicated split bearer on the first path (e.g., the direct path). For example, at the triggering event, remote UE 113 can activate duplication of a split SRB (e.g., SRB1 or SRB2) and send an RRC message on the second path (e.g., the indirect path). Furthermore, PDCP duplication can be applied to the initial configuration of an SRB as a non-duplicated bearer. The non-duplicated SRB can be activated based on PDCP-duplication, switching to a duplicated split SRB at the triggering event. The SRB can then be activated on the second path (e.g., the indirect path) because SRB1 / 2 has already been mapped at the relay UE's SRAP layer in the multipath configuration.

[0098] - PDCP-switch: This element instructs the remote UE to switch the SRB to the second path (e.g., the indirect path) when a trigger event occurs. The gNB 106 can determine whether the remote UE is configured to switch the SRB on the indirect path. The SRB can initially be configured as a non-separated SRB on the direct path or a non-repeating separated SRB on the direct path (e.g., the first path). Upon triggering an event, the remote UE can switch the SRB to the second path or the indirect path without changing the SRB's configuration type. For example, a non-separated SRB (or a non-repeating separated SRB) on the first or direct path can be switched to a non-separated SRB (or a non-repeating separated SRB) on the second path or the indirect path upon triggering an event. In the case of a non-separated SRB switching to the second path (e.g., the indirect path), the remote UE can switch the SRB's primary path to the second path (e.g., the indirect path) upon triggering an event. Furthermore, a non-separated SRB can have its configuration changed to a non-repeating separated SRB upon triggering an event because the E2E SRB1 / 2 has already been mapped at the relay UE's SRAP layer in the multipath configuration. The configuration of a separate SRB is determined based on a PDCP switch. In the case of a PDCP switch, a non-separate SRB can change its configuration to a separate SRB if its primary path is switched to a secondary path (e.g., an indirect path).

[0099] - PDCP-config1: This element may include or indicate a new PDCP configuration or PDCP configuration for the radio bearer (SRB) after the triggering event occurs and after the configuration of the RRB on the second path or indirect path is completed. When the second path is being used, and the configuration indicated by PDCP-config1 uses the direct path, the remote UE can apply the PDCP configuration indicated by PDCP-config1 for the SRB once the direct path has been (re)established. In the first example, PDCP-config1 may refer to a PDCP-config that was already used for the radio bearer on the first path or direct path before the triggering event. In the second example, after the triggering event, PDCP-config1 may remain empty or retain the existing configuration assigned to the radio bearer on the second path or indirect path (determined by PDCP-duplication or PDCP-switch), so that the radio bearer can retain its configured settings for the second or indirect path after the triggering event. PDCP-config1 may introduce a new configuration for the radio bearer that differs from the earlier configuration. In the example, configuration refers to the type of SRB, and for a separate SRB, whether it has duplication or not.

[0100] When included in the configuration information sent to the remote UE 113, PDCP-config1 indicates to the remote UE 113 what configuration to apply after the triggering event occurs, or both during and after the triggering event. This allows the remote UE 113 to know whether the configuration for the SRB will be applied at the time of the triggering event and then retained, or whether it will only be applied at the time of the triggering event and some other configuration for the SRB (which could be the initial configuration applied on the first path or a new configuration) will be applied after the triggering event. This provides a flexible solution for configuring the SRB for multipath communication.

[0101] Remote UE 113 and relay UE 110 can also send measurement reports to gNB 106 via measurement report message 303 as defined in 3GPP TS 38.331. This report may include Uu measurement information, sidelink measurement information, and additional information about measurements of neighboring cells or other UEs near UE 113. Based on the measurement reports, gNB 106 can decide to reconfigure the direct path in message 304.

[0102] For example, gNB 106 may detect a better Uu quality signal in a neighboring cell or neighboring gNB-DU, and therefore, it may decide to configure remote UE 113 for direct path change. If better Uu quality is detected using a neighboring gNB (e.g., gNB 107), gNB 106 may decide to configure remote UE 113 for handover.

[0103] In another example, gNB 106 may decide to deactivate the direct path for various reasons, including but not limited to: low data traffic in a multipath with better QoS at the indirect path, rerouting data traffic on the indirect path to obtain better coverage, or controlling the load at the connected Pcell (e.g., the cell to which remote UE 113 is connected in the direct path).

[0104] Then, gNB 106 can send a reconfiguration message 305 to the remote UE 113. The reconfiguration message 305 may include, but is not limited to, direct path change or release, direct path deactivation or handover, or relay (re)selection or handover for an indirect path. For example, the reconfiguration message 305 may include reconfiguration information for reconfiguring the remote UE 113, wherein the reconfiguration information indicates one of the following: direct path change or release, direct path deactivation or handover, or relay (re)selection or handover for an indirect path.

[0105] Upon receiving RRCReconfiguration message 305, remote UE 113 can detect direct path reconfiguration and identify that the new configuration results in direct path inactivity. Signaling and data services on the direct path can then be suspended. If the direct path inactivity is triggered by one of the trigger events previously configured according to the configuration for multipath 301a, remote UE 113 can then (in step 306) invoke MP-SRB-PathSwitchConfig-r18 IE and activate the SRB on the indirect path via PDCP repetition or PDCP switching specified in the IE. As a result, remote UE 113 can then use the indirect path for signaling data via or through the SRB.

[0106] For example, gNB 106 can configure remote UE 113 with "non-duplicated split SRB1" in message 301a. The split SRB1 is then activated on the direct path for RRC message exchange (e.g., signaling data exchange) and deactivated on the indirect path. Furthermore, the "non-duplicated split SRB1" configuration may include an MP-SRB-PathSwitchConfig-r18 IE with a list of triggering events (e.g., direct path change as described above). When a triggering event occurs, the MP-SRB-PathSwitchConfig-r18 IE can indicate PDCP duplication. Therefore, remote UE 113 receiving the configuration message 305 indicating a direct path change can trigger a reconfiguration with duplicated split SRB1 based on the configuration information included in message 301a, thereby allowing the exchange of RRC messages 308 via the indirect path. In other words, after determining that a reconfiguration involving a direct path change is required (the direct path change event is in the list of triggering events included in the configuration information received in message 301a), the remote UE 113 is triggered to change the type of the SRB (e.g., to a separate SRB with duplicates), thereby enabling the indirect path to be used for signaling data via the SRB.

[0107] During this SRB handover, the remote UE 113 continues to communicate UL / DL data via the indirect path in 307, for example, using the DRB configured on the indirect path by message 301a.

[0108] For some use cases, such as those involving direct path changes, it may be necessary to exchange RRC messages 308 carried by the SRB via indirect path exchanges. As an example, remote UE 113 can receive configuration message 305 from source gNB-DU1 101 to perform inter-DU direct path changes. Therefore, as... Figure 1a As shown, remote UE 113 can change the direct path 113b to connect to target gNB-DU2 102 via a direct path (e.g., link 113c). However, source gNB-DU1 101 may need to receive RRCReconfigurationComplete message 308 from remote UE 113 to modify or release the remote UE context. Therefore, by allowing remote UE 113 to use the indirect path (113a+110a) for signaling data via or through the SRB, remote UE 113 can exchange RRC messages by maintaining an indirect path connection to source gNB-DU1 101.

[0109] The configuration of a remote UE with a list of triggering events can help the remote UE control the use of SRBs on the indirect path for specific purposes. Furthermore, gNB 106 may not need to reconfigure the SRBs to the indirect path at each triggering event, because the remote UE 113 can configure and control the use of SRBs based on one or more triggering events and information included in the configuration information provided prior to any triggering event (e.g., in message 301a).

[0110] When configuring an SRB on an indirect path (e.g., after signaling via an indirect path is used for SRB), the remote UE 113 can apply PDCP-config1, which was previously specified in MP-SRB-PathSwitchConfig-r18 IE. For example, PDCP-config1 can refer to a PDCP-config already configured for the SRB; therefore, the remote UE 113 can (re)use the initial configuration sent in message 301a (e.g., a separate SRB1 without duplication) or a modified configuration as indicated in message 305 (e.g., a separate SRB1 with duplication) when re-establishing service or communication on the direct path. The direct path can be a previous direct path (such as direct path 113b, etc.) or a new direct path (such as direct path 113c in the case of inter-DU handover or direct path 113d in the case of inter-gNB handover, etc.). For the example of a direct path change between DUs, after establishing link 113c with the target gNB-DU2 102, the remote UE 113 can (re)use the SRB1 configuration sent in message 301a or modified in message 305 on the new direct path 113c. Therefore, after the indirect path change process is completed, the duplicated separate SRB1 activated at the triggering event can be replaced by the non-duplicated separate SRB1 as initially set in message 301a. Similarly, step 309 can be applied after the handover process is completed.

[0111] Step 309 may not apply to some use cases where the direct path is released because the direct path has been released. For direct path deactivation, step 309 is applied once the direct path is reactivated by the network.

[0112] Upon completing the configuration and activation of the direct path sent in message 305, the remote UE 113 may be able to communicate with the network via both uplink and downlink paths in message 310. Otherwise, it may only exchange UL / DL data services on the indirect path.

[0113] Now for reference Figure 4 It illustrates an embodiment of the invention for managing SRBs in wireless communication systems that support multipath communication and relay (such as...). Figure 1a The following is an example message flow for the use of SRB1 on the indirect path in wireless communication systems (such as those shown) to manage direct path failures in multipath transmission systems. By way of example, the following description is for the case where the first path is a direct path and the second path is an indirect path (between the UE and the network via a relay node). It should be understood that the following description can also be applied to cases where the first path is an indirect path and the second path is either a direct path or an indirect path.

[0114] The first or direct path may suffer severe link degradation, leading to path failure and consequently, interruption or restriction of services and signaling at the direct path. Furthermore, the gNB may face repeated RRC fault configurations at the direct path. These issues can be classified as direct path link problems and may need to be reported to the network by a remote UE via a second path (e.g., an indirect path) within the multipath transmission system. Note that in the case of an indirect path, either the Uu link or the PC5 link, or both, may suffer severe link degradation, RLF, or RRC fault configurations: these may be classified as indirect path link problems and may need to be reported to the network by a remote UE via a second path (e.g., a direct or indirect path).

[0115] For all or any of these link problems Figure 4 It provides solutions for maintaining network connectivity by using a second path or indirect path, and is more specifically used for reporting direct path link problems via indirect paths in multipath transmission systems. Direct path link problems are not limited to those listed above. Message flow 400 represents the exchange of RRC messages between serving gNB106, serving relay UE 110, and remote UE 113.

[0116] Remote UE 113 can receive multipath configuration from the network in message 401a, and respond with configuration completion message 401b after applying the multipath configuration. For example, remote UE 113 can apply multipath configuration to configure or set up remote UE 113 to communicate data via or through the configured radio bearers (SRB, DRB) using direct path 113b and indirect path (113a+110a). In particular, and Figure 4In the example shown, the multipath configuration from gNB 106 configures the remote UE 113 to activate or set an SRB at least on the direct path 113b. Whether an indirect path is used at this time will depend on the type of SRB and whether separate SRB duplication is activated. Similar to message 301a, multipath configuration message 401a may include a list of triggering events related to direct path link problems, such as direct path failures (e.g., RLF), direct path link degradation, or direct path RRC failures (e.g., configuration failures).

[0117] In the example, the multipath configuration included in message 401a sent to remote UE 113 can be inserted into the RRCReconfiguration message defined in TS38.331. The RRCReconfiguration message can include the information element described below (referred to as MP-SRB-PathSwitchConfig-r18). This IE can be added to either the radiobearerconfig IE or the PDCP-config IE included in the RRCReconfiguration message.

[0118] According to one example, the configuration information for the information element MP-SRB-PathSwitchConfig-r18 used to configure SRB may include all or some of the following information:

[0119] - A list of triggering events, including one or more of the following: direct path failure (e.g., RLF), direct path link degradation, and direct path RRC failure (e.g., configuration failure). Other triggering events related to direct path link problems can be added to the enumeration list.

[0120] - PDCP-duplication: This element indicates that a remote UE will activate PDCP duplication when a triggering event occurs. gNB 106 can configure a remote UE to activate PDCP duplication when a triggering event occurs. Duplication can be activated if the SRB is initially configured as a non-duplicated split bearer on the first path (e.g., the direct path). For example, at the triggering event, remote UE 113 can activate duplication of a split SRB (e.g., SRB1 or SRB2) and send an RRC message on the second path (e.g., the indirect path). Furthermore, PDCP duplication can be applied to the initial configuration of an SRB as a non-duplicated bearer. The non-duplicated SRB can be activated based on PDCP-duplication, switching to a duplicated split SRB at the triggering event. The SRB can then be activated on the second path (e.g., the indirect path) because SRB1 / 2 has already been mapped at the relay UE's SRAP layer in the multipath configuration.

[0121] - PDCP-switch: This element indicates that the remote UE will switch the SRB to the second path (e.g., the indirect path) when a trigger event occurs. gNB 106 can determine whether the remote UE is configured to switch the SRB on the second path or the indirect path. The SRB can initially be configured as a non-separated SRB on the direct path or a non-repeating separated SRB on the direct path (e.g., the first path). At the trigger event, the remote UE can switch the SRB to the second path or the indirect path without changing the SRB's configuration type. For example, a non-separated SRB (or a non-repeating separated SRB) on the first or direct path can be switched to a non-separated SRB (or a non-repeating separated SRB) on the second path or the indirect path at the trigger event. In the case of a non-separated SRB switching to the second path (e.g., the indirect path), the remote UE can switch the SRB's primary path to the second path (e.g., the indirect path) at the trigger event. Furthermore, a non-separated SRB can have its configuration changed to a non-repeating separated SRB at the trigger event because the E2E SRB1 / 2 has already been mapped at the relay UE's SRAP layer in the multipath configuration. The configuration of a separate SRB is determined based on a PDCP switch. In the case of a PDCP switch, a non-separate SRB can change its configuration to a separate SRB if its primary path is switched to a secondary path (e.g., an indirect path).

[0122] - PDCP-config1: This element may include or indicate a new PDCP configuration or PDCP configuration for the radio bearer (SRB) after the triggering event occurs and after the configuration of the RRB on the second path or indirect path is completed. When the second path is being used, and the configuration indicated by PDCP-config1 uses the direct path, the remote UE can apply the PDCP configuration indicated by PDCP-config1 for the SRB once the direct path has been (re)established. In the first example, PDCP-config1 may refer to a PDCP-config that was already used for the radio bearer on the first path or direct path before the triggering event. In the second example, after the triggering event, PDCP-config1 may remain empty or retain the existing configuration assigned to the radio bearer on the second path or indirect path (determined by PDCP-duplication or PDCP-switch), so that the radio bearer can retain its configured settings for the second or indirect path after the triggering event. PDCP-config1 may introduce a new configuration for the radio bearer that differs from the earlier configuration. In the example, configuration refers to the type of SRB, and for a separate SRB, whether it has duplication or not.

[0123] After multipath configuration at remote UE 113, in 402, UL / DL data is communicated between the remote UE and the network via radio bearer using these two paths (i.e., direct path and indirect path).

[0124] In the first aspect, remote UE 113 may detect a direct path failure in 403, and therefore generate an MCGFailureInformation report at the remote UE. This report is sent by remote UE 113 to gNB 106 using SRB1. When the direct path is suspended due to a path failure, in order to send the MCGFailureInformation report to the network (e.g., gNB 106), remote UE 113 may need to send the MCGFailureInformation report via an indirect path (if SRB1 is also configured on that path).

[0125] Upon detection of a direct path failure, in step 404, the remote UE 113 is triggered to activate SRB1 on the indirect path. For example, the remote UE 113 can be configured with a non-separate SRB1 as specified in message 401a for multipathing. Therefore, non-separate SRB1 is supported only on the direct path. gNB 106 can configure its remote UE 113 in message 401a with one or more trigger events including a direct path failure event, and in response to determining that a direct path failure has occurred, triggers the remote UE 113 to use the indirect path to carry signaling data via SRB1. If the configuration information in message 401a also includes PDCP-switch information, the remote UE 113 is triggered to switch from non-separate SRB1 to the indirect path upon trigger event by activating the PDCP-switch. Therefore, upon a direct path failure trigger event, the remote UE 113 can switch from the direct path to the indirect path with non-separate SRB1, and subsequently, MCGFailureInformation report 405 can be carried to gNB 106 via the indirect path using SRB1.

[0126] The gNB 106 can receive MCGFailureInformation reports from the remote UE 113 and can decide to restore the current direct path, change the primary cell (Pcell) of the direct path, or release the direct path. The remote UE 113 can maintain its current configuration (SRB1 on the indirect path) until it receives a new RRCReconfiguration message from the network.

[0127] On the other hand, remote UE 113 may suffer repeated RRC failures in step 403, such as RRCreconfiguration failures or RRCResume failures. Then, remote UE 113 may detect a problem exchanging RRC messages with gNB 106 via the direct path in step 404, and may trigger SRB1 on the indirect path. For example, a non-repeating, separate SRB1 may initially be configured by gNB 106 in message 401a. Furthermore, gNB 106 may (via message 401a) configure remote UE 113 using a configuration failure as a triggering event, and in response to determining or detecting a configuration failure, trigger remote UE 113 to use the indirect path to carry signaling data via SRB1. If the configuration information in message 401a also includes PDCP-switch information, remote UE 113 is triggered to switch from non-repeating SRB1 to the indirect path (PDCP-switch) upon a specified triggering event including a direct path failure. Therefore, remote UE 113 can switch to a non-repeating, separate SRB1 by switching its primary path to the indirect path in 405 and subsequently exchanging RRC messages via the indirect path. Remote UE 113 can report a Uu-RRC fault occurring on the direct path via the indirect path in RRC message exchange 405.

[0128] The configuration of the remote UE 113 with a list of triggering events can help the remote UE control the occasional use of the SRB on the indirect path. Furthermore, the gNB 106 may not need to reconfigure the SRB to the indirect path at each triggering event, because the remote UE 113 can configure and control the use of the SRB based on one or more triggering events and information included in the configuration information provided prior to any triggering event (e.g., in message 401a).

[0129] The case of a non-split SRB1 (or a non-repeating split SRB1) on the direct path may trigger a connection re-establishment in the event of a direct path failure, thus requiring the exchange of additional signaling messages between the remote UE 113 and gNB 106. Furthermore, the re-establishment process may risk the loss of multipath configuration. The method in flowchart 400 configures SRB1 by switching or repeating it on the indirect path at the time of a predefined triggering event (such as an RLF), thus enabling the exchange of additional signaling messages with the network in the event of a direct path failure. This can help avoid the need for a re-establishment process by providing a smooth transition from the SRB to the operational path (e.g., the indirect path).

[0130] When sending RRC message 405, remote UE 113 can apply the PDCP-config1 specified in the IE as described above. In the example, PDCP-config1 can indicate that the current PDCP-config will be used after the triggering event and the configuration of SRB1 on the indirect path; therefore, the remote UE can maintain SRB1 on the indirect path. In another example, PDCP-config1 can indicate that after the triggering event and the configuration of SRB1 on the indirect path, SRB1 in the non-duplicated, separate configuration on the direct path will be used. In this case, remote UE 113 can wait for the re-establishment of the direct path before applying PDCP-config1. On the other hand, remote UE 113 may need to continue using SRB1 on the indirect path.

[0131] Now for reference Figure 5 It illustrates an embodiment of the present invention for managing wireless communication systems (such as those supporting multipath communication and relay) that support multipath communication and relay. Figure 1a The example message flow in a wireless communication system (such as the one shown) is particularly used to manage the use of backward-compatible SRB1 on indirect paths in a multipath transmission system. By way of example, the following description addresses the case where the first path is either a direct or indirect path and the second path is an indirect path (between the UE and the network via a relay node). It should be understood that the following description can also be applied to the case where the first path is an indirect path and the second path is a direct path.

[0132] According to the diagram, remote UE 113 is connected via... Figure 1a The direct link 113b shown is connected to gNB 106. In this example, gNB 106 can configure a remote UE for multipathing by adding (or changing) indirect paths. Therefore, gNB 106 can configure remote UE 113 and serving U2N trunk UE 110 to establish (or change) indirect paths.

[0133] Flowchart 500 shows the signaling message exchange between the core network (120, 130), serving gNB 106, serving relay UE 110, and remote UE 113.

[0134] U2N relay UE 110 can be added in any RRC state. Therefore, U2N relay UE 110 can be in a disconnected RRC state, such as RRC_IDLE or INACTIVE. At the indirect path addition or change process, a PC5-RRC message can be sent by remote UE 113 to trigger the added version 18 U2N relay UE to enter the CONNECTED state.

[0135] However, U2N relay UE 110 can be a version 17 relay UE. The new PC5-RRC method is not backward compatible; therefore, if relay UE 110 is a version 17 U2N relay UE, relay UE 110 cannot be triggered into the CONNECTED state by this PC5-RRC message. Therefore, conventional procedures, such as using the RRCReconfigurationComplete message as described in version 17, should be reused to trigger a version 17 U2N relay UE into the CONNECTED state.

[0136] In order to send an RRCReconfigurationComplete message to a relay UE on an indirect path, an SRB1 should be configured on that path. However, a non-separate SRB1 or a non-repeating separated SRB1 configuration may restrict the exchange of RRC messages to the direct path only. Therefore, the remote UE 113 will not be able to send messages (such as the RRCReconfigurationComplete message) through the indirect path to trigger the relay UE to enter the RRC connection state.

[0137] To address backward compatibility issues, the network should be able to distinguish between relay UEs of version 17 and relay UE candidates of version 18 or later (i.e., ≥ version 18, hereinafter referred to as 18+). At the time of relay discovery, (re)selection, and indirect path addition (or change), remote UEs and / or gNBs cannot recognize relay UEs of version 17. However, U2N relay UEs of version 18 (or later) may be able to be recognized as relay UEs of version 18 (or later) by virtue of their capabilities.

[0138] In the first example, a version 18+U2N relay UE can be transmitted via NG-RAN to the core network 120 (in Figure 1b During the registration request 501 (as shown in the diagram), the UE communicates its capabilities in 5G ProSe. Referring to TS 23.304, Clause 6.6.2, the UE can indicate its support for one or more ProSe capabilities (such as 5G ProSe direct discovery, 5G ProSe Layer 2 or Layer 3 U2N relay UE, etc.) during the registration process. Version 18 can introduce new capabilities (such as multipathing), thus allowing the UE to include new features related to its capabilities as a Layer 2 / Layer 3 remote UE capable of multipathing or a Layer 2 / Layer 3 relay UE capable of multipathing. For example, a new PC5-RRC message can be used to trigger a Layer 2 / Layer 3 U2N relay UE capable of multipathing. Therefore, exchanging its 5G ProSe capabilities and multipathing capabilities during the registration phase can help the gNB (or NG-RAN node) and core network classify the UE based on its capabilities at an early stage.

[0139] In the second example, a version 18+ U2N relay UE can communicate its capabilities during discovery procedure 502 or later during PC5-RRC establishment with remote UE 113 by broadcasting its capabilities or sending them to remote UE 113. In this case, remote UE 113 knows from the U2N relay UE capabilities whether relay UE 110 is a version 18+ relay UE, and therefore knows whether the relay UE can be triggered into the RRC_CONNECTED state via a PC5-RRC message. Remote UE 113 may or may not communicate the U2N relay UE capabilities to gNB 106 during the discovery phase. For example, the selected relay UE 110 can communicate its capabilities as a 5G ProSe Layer 2 U2N relay UE capable of multipathing (i.e., relay UE 110 is a version 18+ relay UE), therefore, remote UE 113 then does not need to consider backward compatibility issues in multipath configuration.

[0140] In the third example, a version 18+U2N relay UE can include its relay UE capability when establishing an RRC connection 501 with NG-RAN or gNB 106. For example, the version 18+U2N relay UE capability can be included in the RRCSetupRequest message sent by relay UE 110 to gNB 106, or later in a future RRC exchange message. gNB 106 then knows whether relay UE 110 is a Layer 2 or Layer 3 U2N relay UE capable of multipathing. If multipathing capability is not communicated at relay UE 110, gNB 106 can then consider backward compatibility issues at the configuration of remote UE 113 for multipathing 504.

[0141] In the fourth example, remote UE 113 can query relay UE 110 for its capabilities by sending a UECapabilityEnquirySidelink message. This message may optionally include the remote UE 113's capabilities in the UECapabilityInformationSidelink information element. This capability may carry information to inform relay UE 110 that remote UE 113 supports triggering relay UE 110 into RRC_CONNECTED (i.e., supports sending PC5-RRC messages to trigger relay UE 110 into RRC_CONNECTED). From the remote UE's perspective, this means that remote UE 113 is able to send this trigger message to relay UE 110. In response, relay UE 110 sends a UECapabilityInformationSidelink message, which includes the relay UE 110's capabilities (and, for example, whether relay UE 110 supports being triggered into RRC_CONNECTED by remote UE 113 (e.g., the relay UE supports PC5_trigger)).

[0142] In a variant, support for the PC5_trigger feature may be mandatory for version 18 sideline relay UEs. Therefore, either relay UE 110 or remote UE 113 with the AccessStratumReleaseSidelink field set to rel18 in UECapabilityInformationSidelink should support this feature (i.e., PC5_trigger). This UECapabilityInformationSidelink message can be sent autonomously by relay UE 110 to inform remote UE 113 of its capabilities.

[0143] According to the aforementioned procedures (e.g., 501 or 502), but not limited to these described procedures and other procedures may be used, a version 18+ U2N relay UE can then be identified as version 18+ by the network or remote UE 113 through its capabilities. In this case, backward compatibility is not considered in the multipath configuration. However, backward compatibility should be addressed when the remote UE 113 or the network does not identify the U2N relay UE as version 18+. Figure 5 The message flow in the document aims to address backward compatibility issues related to unrecognized relay UE capabilities associated with version 18+. In other words, Figure 5 The message flow in the protocol is designed to address the following backward compatibility issues: relay nodes are not identified as relay nodes of 3GPP version 18 or are not identified as relay nodes of a 3GPP version higher than 3GPP version 18.

[0144] Serving relay UE 110 is a version 17 relay UE that is not recognized by the network as having capabilities associated with version 18+. This relay UE is in a disconnected state 503 (e.g., RRC_INACTIVE or IDLE). Remote UE 113 can receive multipath configuration from the network in message 504, and then apply the multipath configuration to configure or set remote UE 113 to communicate data via or through configured radio bearers (SRB, DRB) using direct path 113b and indirect path (113a+110a). Specifically, and Figure 5 In the example shown, the multipath configuration from gNB 106 configures the remote UE 113 to activate or set the SRB at least on the direct path 113b.

[0145] gNB 106 may include a backward compatibility indication in the multipath configuration message 504. For example, gNB 106 may include information in message 504 indicating that relay UE 110 is not recognized as a relay node of version 18+. In another example, gNB 106 may send a separate message after message 504 to indicate that relay UE 110 is not recognized as a relay node of version 18+. Alternatively, remote UE 113 may determine itself that relay UE 110 is not recognized as a relay node of version 18+ based on information received from relay UE 110 (e.g., capability information) (such as messages received from relay UE 110 as discussed above). Therefore, remote UE 113 may know in step 505 (e.g., based on the information in message 504) that it is necessary to trigger the version 17 relay UE to enter the connected state by sending the RRCReconfigurationComplete message 507 via the indirect path. For example, after remote UE 113 determines that relay UE is not identified as a relay node of version 18+, remote UE 113 is triggered to activate SRB on the indirect path and sends a message (e.g., message 507) to relay UE 110 via the indirect path and SRB to trigger relay UE 110 to enter the RRC connected state. Remote UE 113 may send message 507 after remote UE 113 determines that relay UE 110 is not identified as a relay UE of version 18+, or after remote UE 113 determines that relay UE 110 is not identified as a relay UE of version 18+ and is still in a disconnected RRC state. Remote UE 113 may determine that relay UE 110 is in a disconnected RRC state based on information received from gNB 106. To this end, remote UE 113 may occasionally activate SRB1 on the indirect path to send configuration complete message 507.

[0146] Similar to messages 301a and 401a, multipath configuration message 504 may include one or more triggering events related to backward compatibility issues. For example, one or more triggering events may include one or more of the following events: an event where the relay node is not identified as a version 18 relay node or is not identified as a relay node of a version higher than version 18 (i.e., not identified as a version 18+ relay node); and an event where the relay node is in a disconnected RRC state and is not identified as a version 18 or higher relay node.

[0147] In the example, the multipath configuration included in message 504 sent to remote UE 113 can be inserted into the RRCReconfiguration message defined in TS38.331. The RRCReconfiguration message can include the information element described below (referred to as MP-SRB-PathSwitchConfig-r18I). This IE can be added to either the radiobearerconfig IE or the PDCP-config IE included in the RRCReconfiguration message.

[0148] According to one example, the configuration information for the information element MP-SRB-PathSwitchConfig-r18 may include all or some of the following information:

[0149] - A list of one or more triggering events for backward compatibility, including one or more of the following events: such as the event that the relay node is not identified as a version 18 relay node or is not identified as a relay node of a version higher than version 18 (e.g., not identified as a version 18+ relay node), and the event that the relay node is in a disconnected RRC state and is not identified as a version 18 or higher relay node.

[0150] - A backward-compatible indication. For example, a backward-compatible indication indicates that relay UE 110 is not identified as a relay node of version 18+, or that relay UE 110 is in a disconnected RRC state and is not identified as a relay node of version 18+. Upon receiving this indication, the remote UE may trigger or activate SRB1 on the indirect path to send a configuration complete message 507.

[0151] - PDCP-duplication: This element instructs a remote UE to activate PDCP duplication when a triggering event occurs (e.g., when the UE determines a backward compatibility issue). gNB 106 can configure a remote UE to activate PDCP duplication in response to a backward compatibility indication. Duplication can be activated if the SRB was initially configured as a separate bearer on the direct or indirect path. For example, when backward compatibility is indicated, remote UE 113 can activate duplication of a separate SRB (e.g., SRB1 or SRB2) and send RRC messages on the indirect path. Alternatively, PDCP-duplication can be applied to non-separate SRBs active on the direct or indirect path. PDCP-duplication can switch a non-separate SRB configuration to a separate SRB configuration, where duplication ensures the exchange of RRC messages on the added / changed indirect path.

[0152] - PDCP-switch: This element instructs the remote UE to switch the SRB to a second path (e.g., an indirect path) when a triggering event occurs (e.g., when the UE determines there is a backward compatibility issue). The gNB 106 can determine whether the remote UE should switch the SRB on the indirect path. The SRB can initially be configured as a non-separated SRB on either the direct or indirect path, or a non-repeating separated SRB on either the direct or indirect path. For backward compatibility indication, the remote UE can switch the SRB to the indirect path without changing the SRB's configuration type. For example, a non-separated SRB (or a non-repeating separated SRB) on the direct path can be switched to a non-separated SRB (or a non-repeating separated SRB) on the indirect path for backward compatibility purposes by switching its primary path. Thus, the primary path becomes the indirect path.

[0153] - PDCP-config1: This element may include or indicate a new PDCP configuration or PDCP configuration for the radio bearer (SRB) after the triggering event occurs and after the configuration of the RRB on the second path or indirect path is completed. When the second path is being used, and the configuration indicated by PDCP-config1 uses the direct path, the remote UE can apply the PDCP configuration indicated by PDCP-config1 for the SRB once the direct path has been (re)established. In the first example, PDCP-config1 may refer to a PDCP-config that was already used for the radio bearer on the first path (direct path or indirect path) before the triggering event. In the second example, after the triggering event, PDCP-config1 may remain empty or retain the existing configuration assigned to the radio bearer on the second path or indirect path (determined by PDCP-duplication or PDCP-switch), so that the radio bearer can retain its configured settings for the second or indirect path after the triggering event. PDCP-config1 may introduce a new configuration for the radio bearer that differs from the earlier configuration. In the example, configuration refers to the type of SRB, and for detached SRBs, it refers to whether they have duplicates or not.

[0154] gNB 106 may configure or set SRB1 to a non-split SRB mode or a non-repeating split SRB in the configuration information included in the multipath configuration message 504. However, gNB 106 may include backward-compatible indications for multipath configuration, where PDCP repetition or PDCP switching is required to trigger the version 17 relay UE 110 to enter the connected state (as in step 506).

[0155] In the first aspect, PDCP repetition can be used to activate a non-repeating separate SRB1 on the indirect path. Then, SRB1 is set as a repeating separate SRB1 on the indirect path to trigger relay UE 110 of version 17 to enter a connected state (as in 506). Remote UE 113 is then connected via the direct path (…). Figure 5 (Not shown in the image) and the indirect path send an RRCReconfigurationComplete message 507 to gNB 106. The RRCReconfigurationComplete message 507 triggers the relay UE of version 17 to enter the RRC_CONNECTED state 508. After the indirect path addition or change is completed, the remote UE 113 can apply the initial configuration of the non-repeating split SRB1 on the direct path in 509.

[0156] Secondly, PDCP handover can be used to activate a non-repeating split SRB1 on the indirect path. The non-repeating split SRB1 can then switch its primary path to the indirect path to trigger the version 17 relay UE 110 to enter the connected state (as in 506). The remote UE 113 sends an RRCReconfigurationComplete message 507 to gNB 106 via the indirect path. The RRCReconfigurationComplete message 507 triggers the version 17 relay UE to enter the RRC_CONNECTED state 508. After completing the configuration of SRB1 on the indirect path, the remote UE 113 can apply the initial configuration of the non-repeating split SRB1 on the direct path in 509.

[0157] Thirdly, PDCP handover can be used to activate the non-separated SRB1 on the indirect path. The non-separated SRB1 can then switch its primary path to the indirect path to trigger the version 17 relay UE 110 into the RRC connected state (as in 506). The remote UE 113 sends an RRCReconfigurationComplete message 507 to the gNB 106. The RRCReconfigurationComplete message 507 triggers the version 17 relay UE to the RRC_CONNECTED state in 508.

[0158] When configuring SRB1 on the indirect path, as discussed above, the remote UE 113 can apply the PDCP-config1 specified in the IE. For example, PDCP-config1 can point to the initial PDCP-config initially set for SRB1, so the remote UE 113 can apply the initial configuration of the non-detached SRB1 on the direct path in 509.

[0159] Then, the remote UE 113 can communicate with the gNB 106 via two paths (e.g., a direct path and an indirect path) in the multipath transmission system. Then, in 510, UL / DL data is transmitted between the remote UE 113 and the gNB 106.

[0160] Configuring the remote UE 113 using backward compatibility directives can help the remote UE 113 control the occasional use of SRBs on indirect paths. Furthermore, the gNB 106 may not need to reconfigure the SRBs when indirect paths are added or changed, because the remote UE 113 can configure and control the use of SRBs. Additionally, backward compatibility directives allow for not restricting the SRB configuration type to discrete SRBs with repetition: as discussed above, non-discrete SRB1 or non-repetitive discrete SRB1 can be configured.

[0161] Still referencing Figure 7 This is a flowchart illustrating the steps of a method 700 for managing the use of SRBs in a wireless communication system according to one or more embodiments of the present invention. The wireless communication system supports multipath communication and relaying between a UE and a network. The wireless communication system supports side-link relaying and / or other point-to-point relaying, such as relaying via WiFi or Bluetooth. In the case where the wireless communication system supports side-link relaying, the UE is referred to as a remote UE, and the relay node is referred to as a relay UE (e.g., a UE operating or functioning as a relay). The network of the wireless communication system includes at least one base station. Method 700 is performed at the UE. Regarding... Figure 1a In the example shown, the UE performing method 700 can be a UE or a remote UE 113, and the base station can be base station 106 (also referred to as gNB 106). Figure 7 The image shown and about Figure 7 The described method 700 can be performed by software elements and / or hardware elements. Therefore, for example, as... Figure 7 The image shown and about Figure 7 The described method can be performed by a device for a UE, the device including one or more processing units configured to execute the method. The UE can, for example... Figure 6 The images and references shown Figure 6 The communication device 600 described is implemented therein, wherein, as Figure 7 The image shown and about Figure 7 The described method is performed by one or more processing units (such as processing unit 611, etc.).

[0162] In summary, at step 702, the remote UE 113 activates an SRB (e.g., SRB1 or SRB2) for or on the first path between the remote UE 113 and the gNB 106. The remote UE 113 can receive configuration information from the gNB 106 for configuring the SRB on the first path, and after receiving the configuration information, the remote UE 113 activates the SRB on the first path. The configuration information for the SRB on the first path can be included in a multipath configuration message for configuring multipath communication (such as messages 301a, 401a, or 504 received by the remote UE 113 from the gNB 106).

[0163] Remote UE 113 receives from gNB 106 ( Figure 7Configuration information (e.g., SRB1 or SRB2 configured on the first path) is used to configure an SRB on a second path between remote UE 113 and gNB 106. The configuration information for the SRB on the second path can be included in a multipath configuration message (such as messages 301a, 401a, or 504 received from gNB 106 at remote UE 113), or the configuration information for the SRB on the second path can be received later in a separate message. The configuration information for the second path can include all or part of the information in MP-SRB-PathSwitchConfig-r18 IE as described above. The configuration information for the SRB on the first path and the configuration information for the SRB on the second path can be included in the same multipath configuration message, and the SRB on the first path is activated upon receiving such a multipath configuration message.

[0164] The configuration information for the SRB on the second path includes trigger event information indicating one or more trigger events for initiating the use of the SRB on the second path. One or more trigger events may include one or more of the following: one or more events where the first path becomes inactive; one or more events where a link problem occurs on a link of the first path; or a backward compatibility event.

[0165] After receiving configuration information for configuring the SRB on the second path, at step 706, the remote UE 113 uses the second path to carry signaling or signaling data via or through the SRB after determining that one or more triggering events have occurred.

[0166] The first path is one of the direct path between remote UE 113 and gNB 106 (such as a direct path including link 113b) and the indirect path between remote UE 113 and gNB 106 including a relay node or relay UE (such as an indirect path including relay UE 110 and links 113a and 110a), and the second path is one of the direct path and the indirect path.

[0167] One or more events that cause the first path to become inactive include at least one of the following: change of the first path; release of the first path; handover of the first path; deactivation of the first path; relay (re)selection of a relay node when the first path is an indirect path; relay handover of a relay node when the first path is an indirect path. Re)selection or handover of a relay UE on the first indirect path may also result in deactivation of the first path.

[0168] One or more events that cause a link problem on the first path include at least one of the following: Radio Link Failure (RLF) on the first path link; Link degradation on the first path link; Failure configuration of the first path. If the first path is an indirect path, one or more events that cause a link problem on the first path include at least one of the following: RLF on the link between the relay node and the base station (e.g., Uu-RLF); RLF on the link between the UE and the relay node (PC5-RLF or UE-UE link failure).

[0169] Backward compatibility events include one of the following: an event where the relay node is not identified as a 3GPP version 18 relay node or is not identified as a relay node of a 3GPP version higher than 3GPP version 18 (i.e., as discussed above, the relay node is not identified as a version 18+ relay node); or an event where the relay node is in a non-connected RRC state (e.g., RRC_INACTIVE / IDLE) and is not identified as a relay node of 3GPP version 18 or a higher than 3GPP version 18. Backward compatibility events can be any other event (e.g., PC5 triggering such as entering an RRC connected state) that indicates that the relay UE node will not be able to respond to any procedure outlined in 3GPP version 18 or later to wake it up, thus allowing the relay UE node to be used for SRB communication signaling between the remote UE and the gNB.

[0170] Triggering event information can include the information referenced above. Figures 3 to 5 A list of one or more triggering events.

[0171] As mentioned above Figure 3 As discussed, gNB 106 can decide to reconfigure the first path (e.g., reconfigure the multipath configuration). This decision can be based on measurement reports received from remote UE 113 and relay UE 110, or on QoS and / or load on the first and second paths. For example, gNB 106 can decide to configure remote UE 113 to change / release the first path, deactivate the first path, hand over the first path, perform relay (re)selection if the first path is an indirect path, and perform relay handover if the first path is an indirect path. Therefore, remote UE 113 can receive from gNB 106 a message including configuration information indicating the reconfiguration of the first path. This message can be the reconfiguration message 305 discussed above. The reconfiguration information can indicate one of the following: changing / releasing the first path, deactivating the first path, handing over the first path, performing relay (re)selection if the first path is an indirect path, and performing relay handover if the first path is an indirect path.

[0172] In an example scenario where one or more triggering events include one or more events such as a link problem occurring on a link in the first path, the remote UE 113 can determine that a link problem exists on the first path (e.g., RLF on the link in the first path, link degradation on the link in the first path, fault configuration (or recurring configuration failures)), and after such determination, the remote UE 113 is triggered to use the second path to carry signaling via SRB (SRB1 / 2). The signaling may include... Figure 4 The signaling sent in the 405 error message can include MCGFailureInformation reports or RRC messages (such as messages reporting Uu-RRC failures). The above is about... Figure 4 The discussion provides additional details for this example situation.

[0173] In an example scenario where one or more triggering events include a backward compatibility event, and the first path is either a direct or indirect path and the second path is an indirect path between remote UE 113 and gNB 106 that includes a relay node (e.g., relay UE 110), after determining a backward compatibility issue with relay UE 110, remote UE 113 activates an SRB on the second path and uses the second path to send a message via the SRB to relay UE 110 to trigger the relay node into the RRC_CONNECTED state. This message can be an RRC message, such as the one referenced above. Figure 5Message 507, etc., are discussed. Remote UE 113 can determine the existence of a backward compatibility issue based on information received from gNB 106 or relay UE 110. For example, remote UE 113 can receive information from relay UE 110 or gNB 106 indicating that relay UE 110 is not identified as a relay node of 3GPP version 18 or not identified as a relay node of a version higher / later than 3GPP version 18 (i.e., not identified as a version 18+ relay node), and can determine the existence of a backward compatibility issue based on this received information. Remote UE 113 can receive information from gNB 106 indicating that a relay node in the indirect path is in a disconnected RRC state and is not identified as a version 18+ relay node. The information (sent by gNB 106 or relay UE 110) can indicate the capabilities of relay UE 110: for example, whether relay UE 110 supports being triggered by remote UE 113 to enter RRC_CONNECTED (e.g., relay UE 110 supports PC5 triggering, 5G ProSe capability, multipath capability, or any other information indicating to gNB 106 whether relay UE 110 can be triggered to enter RRC connected state in response to any version 18 or later process (such as the AccessStratumReleaseSidelink field being set to rel18, etc.)). The information received from gNB 106 can be sent in multipath configuration message 504. Information received from relay UE 110 can be received in SIB messages (broadcast by relay UE 110), in discovery messages as part of discovery procedure 502, in RRC messages during PC5 establishment (between remote UE 113 and relay UE 110), or in UECapabilityInformationSidelink messages (e.g., with the AccessStratumReleaseSidelink field set to rel18 in UECapabilityInformationSidelink). Information sent by relay UE 110 can be sent in response to a request sent by remote UE 113. For example, remote UE 113 can send a UECapabilityEnquirySidelink message, and in the response, it can receive a UECapabilityInformationSidelink message including the capabilities of relay UE 110 (such as whether relay UE 110 supports entering RRC_CONNECTED triggered by remote UE 113 (e.g., relay UE 110 supports PC5 triggering)). The above is about... Figure 5 The discussion provides additional details for this example situation.

[0174] The activated SRB for the first path can be a non-separated bearer type SRB (e.g., non-separated SRB1 or non-separated SRB2) or a non-repeating separated bearer type SRB (e.g., non-repeating separated SRB1 or non-repeating separated SRB2).

[0175] In the example, the configuration also includes PDCP information indicating the SRB type to be used for the SRB when / when one or more triggering events are determined to have occurred, or after. If the active SRB on the first path is a non-split bearer type SRB or a non-repeating split bearer type SRB, after determining the occurrence of one or more triggering events, the remote UE 113 then determines, based on the PDCP information, whether to change the type of SRB to be configured on the second path. The PDCP information may include at least one of the following: PDCP repetition configuration information (e.g., as mentioned above regarding...). Figure 3 , Figure 4 and Figure 5 The PDCP duplication discussed here is used to configure the UE to activate PDCP duplication after determining that one or more triggering events have occurred; PDCP switching configuration information (e.g., as mentioned above regarding...) Figure 3 , Figure 4 and Figure 5 The PDCP-switch discussed here is used to configure the UE to switch the SRB to the second path after determining that one or more triggering events have occurred; PDCP configuration information (e.g., as mentioned above regarding...) Figure 3 , Figure 4 and Figure 5 The PDCP-config1 discussed herein is used to indicate to the UE the type of SRB to be used for the SRB after the configuration of the SRB on the second path has been completed, or when or after the occurrence of one or more triggering events is determined.

[0176] If the SRB activated on the first path is a non-separate bearer type SRB, after determining that one or more triggering events have occurred, the remote UE 113 can switch the SRB to the second path based on PDCP information and use the second path to carry signaling data through the SRB: for example, in the case where there is no type change, the handover can be based on information provided by PDCP-switch elements (such as when PDCP-switch is activated).

[0177] In the case where the SRB activated on the first path is a non-repeating, separate bearer type SRB, after determining the occurrence of one or more triggering events, the remote UE 113 can activate the SRB on the second path based on PDCP information and use the second path to carry signaling data via the SRB: for example, in the case where there is no type change, the activation of the SRB on the second path can be based on information provided by PDCP-switch elements (such as when the PDCP-switch is activated).

[0178] If the active SRB on the first path is a non-separate bearer type SRB, after determining that one or more triggering events have occurred, the remote UE 113 may, based on PDCP information, change the type of the SRB for the second path to a separated bearer type with or without duplication, switch the SRB to the second path, and use the second path to carry signaling data via the SRB: for example, in the case of a type change, the switch may be based on information provided by the PDCP-duplication element (e.g., PDCP-duplication is activated for duplication), the PDCP-switch element (e.g., PDCP-switch is activated), and / or the PDCP-config1 element (e.g., changing to a non-separate SRB based on information indicated in PDCP-config1).

[0179] If the SRB activated on the first path is a non-duplicated split bearer type SRB, after determining the occurrence of one or more triggering events, the remote UE 113 can change the type of the SRB for the second path to a duplicated split bearer type based on PDCP information, and use the second path to carry signaling data via the SRB: for example, in the case of a type change, the handover can be based on information provided by the PDCP-duplication element (e.g., PDCP-duplication is activated for duplication).

[0180] If the first path is a direct path and is deactivated after the occurrence of one or more triggering events (e.g., by gNB 106, which may send a message to remote UE 113 to deactivate the direct path), and communication on the first path is subsequently re-established (i.e., the direct path is reactivated) or (e.g., during handover to another gNB such as gNB 107) another direct path is established between the UE and the network, remote UE 113 may reactivate the SRB on either the first or the other direct path. The type of SRB for the reactivated first or the other direct path may be indicated in the PDCP configuration information (e.g., PDCP-config1). The SRB type may be the same type used on the initial SRB activated on the first path before using the second path, or it may be the type of SRB used for the second path, or it may be a new type based on the information provided in PDCP-config1.

[0181] Still referencing Figure 8 This is a flowchart illustrating the steps of a method 800 for managing the use of SRBs in a wireless communication system according to one or more embodiments of the present invention. The wireless communication system supports multipath communication and relay between a UE and a network. The wireless communication system supports side-link relay and / or other point-to-point relay, such as via WiFi relay or Bluetooth relay. In the case where the wireless communication system supports side-link relay, the UE is referred to as a remote UE, and the relay node is referred to as a relay UE (e.g., a UE operating or functioning as a relay). The network of the wireless communication system includes at least one base station. Method 800 is performed at the base station. Regarding... Figure 1a In the example shown, the base station performing method 800 can be base station 106 (also referred to as gNB 106), and the UE can be UE 113 or remote UE 113. Figure 8 The image shown and about Figure 8 The described method 800 can be implemented by software elements and / or hardware elements. Therefore, for example, as... Figure 8 The image shown and about Figure 8 The described method can be performed by a device for a base station, which includes one or more processing units configured to perform the method. The base station can be, for example... Figure 6 The images and references shown Figure 6 The communication device 600 described is implemented therein, wherein, as Figure 8 The image shown and about Figure 8 The described method is performed by one or more processing units (such as processing unit 611, etc.).

[0182] In summary, at step 802, gNB 106 sends configuration information (e.g., first configuration information) to remote UE 113 for configuring SRBs on the first path. The configuration information for SRBs on the first path can be included in multipath configuration messages (such as messages 301a, 401a, or 504 received from gNB 106 at remote UE 113).

[0183] At step 804, gNB 106 sends configuration information (e.g., second configuration information) to remote UE 113 for configuring SRBs (e.g., SRB1 or SRB2 configured on the first path) on a second path between remote UE 113 and gNB 106. The configuration information for SRBs on the second path may be included in a multipath configuration message (such as messages 301a, 401a, or 504 received from gNB 106 at remote UE 113) or later included in a separate RRC message. The configuration information for the second path may include all or part of the information in the MP-SRB-PathSwitchConfig-r18 IE as described above. The configuration information for SRBs on the first path and the configuration information for SRBs on the second path may be included in the same multipath configuration message (such as messages 301a, 401a, or 504).

[0184] After receiving configuration information for configuring the SRB on the first path, the remote UE 113 activates the SRB on the first path. The SRB (e.g., SRB1 / 2) is also mapped at the SRAP layer of the relay UE 110 for use in the indirect second path. This mapping can be (pre-)configured or configured at the relay UE 110 by the gNB 106 in a multipath transmission system (e.g., when configuring the relay UE 110 for multipath communication).

[0185] The configuration information for the SRB on the second path includes trigger event information indicating one or more trigger events for initiating the use of the SRB on the second path. One or more trigger events may include one or more of the following: one or more events where the first path becomes inactive; one or more events where a link problem occurs on a link of the first path; or a backward compatibility event.

[0186] After sending the configuration information, at step 806, gNB 106 receives signaling or signaling data from remote UE 113 at least via or through the SRB using a second path. In the case of duplicate split bearers, gNB 106 may receive signaling twice.

[0187] The first path is one of the direct path between remote UE 113 and gNB 106 (such as a direct path including link 113b) and the indirect path between remote UE 113 and gNB 106 including a relay node or relay UE (such as an indirect path including relay UE 110 and links 113a and 110a), and the second path is one of the direct path and the indirect path.

[0188] One or more events that cause the first path to become inactive include at least one of the following: change of the first path; release of the first path; handover of the first path; deactivation of the first path; relay (re)selection of a relay node when the first path is an indirect path; relay handover of a relay node when the first path is an indirect path. Re)selection or handover of a relay UE on the first indirect path may also result in deactivation of the first path.

[0189] One or more events that cause a link problem on the first path include at least one of the following: radio link failure (RLF) on the first path link; link degradation on the first path link; fault configuration of the first path. If the first path is an indirect path, one or more events that cause a link problem on the first path link include at least one of the following: RLF on the link between the relay node and the base station (e.g., Uu-RLF); RLF on the link between the UE and the relay node (PC5-RLF or UE-UE link failure).

[0190] Backward compatibility events include one of the following: an event where a relay node is not identified as a version 18 relay node or is not identified as a relay node of a version higher than version 18 (i.e., as discussed above, a relay node is not identified as a version 18+ relay node); or an event where a relay node is in a non-connected RRC state (e.g., RRC_INACTIVE / IDLE) and is not identified as a version 18 or higher relay node.

[0191] Triggering event information can include the information referenced above. Figures 3 to 5 A list of one or more triggering events.

[0192] As mentioned above Figure 7The gNB can decide to reconfigure the first path (e.g., reconfigure the multipath configuration). This decision can be based on measurement reports received from the remote UE 113 and the relay UE 110, or on QoS and / or load on the first and second paths. For example, the gNB 106 can decide to configure the remote UE 113 to change / release the first path, deactivate the first path, hand over the first path, perform relay (re)selection if the first path is an indirect path, and perform relay handover if the first path is an indirect path. As a result, the gNB 106 can send a message from the gNB 106 to the remote UE 113 including configuration information indicating the reconfiguration of the first path. This message can be the reconfiguration message 305 discussed above. The reconfiguration information can indicate one of the following: change / release the first path, deactivation of the first path, handover of the first path, relay (re)selection if the first path is an indirect path, and relay handover if the first path is an indirect path.

[0193] When the first path is a direct or indirect path and the second path is an indirect path, gNB 106 can receive information associated with the capabilities of the relay node (e.g., relay UE 110). This information may include, for example, information that can be used to determine whether relay UE 110 supports the capability to enter RRC_CONNECTED triggered by remote UE 113 (e.g., relay UE 110 supports PC5 triggering, 5G ProSe capability, multipath capability, or any other information instructing gNB 106 whether relay UE 110 can be triggered to enter RRC connected state in response to any version 18 or later process). For example, gNB 106 may receive this information during the registration phase (e.g., Figure 5 The information received at gNB 106 (501) includes 5G ProSe capabilities received from the relay UE and / or other capabilities that can be used to determine whether the relay UE 110 supports RRC_CONNECTED triggered by the remote UE 113 (e.g., the relay UE 110 supports PC5 triggering). In other words, this information can include the capabilities of the relay UE 110, which can be used to determine whether the relay UE 110 is a 3GPP version 18+ relay node. Information associated with the capabilities of the relay UE 110 received at gNB 106 can be included in the registration request or setup message. Figure 5The information is sent as part of process 501 or in subsequent RRC messages (such as RRCSetupRequest messages). The gNB 106 can then identify whether the relay UE 110 is a 3GPP version 18 or higher / later relay node (i.e., 3GPP version 18+) based on the received capability information. If the relay UE 110 is not identified as a version 18+ relay node, the gNB 106 sends a message to the remote UE 113 indicating that the relay UE 110 has not been identified as a 3GPP version 18 relay node or a relay node of a version higher than 3GPP version 18 (i.e., not identified as a version 18+ relay node). The information sent by the gNB 106 can be sent in multipath configuration message 504. (See above for reference.) Figure 5 More details were discussed.

[0194] The activated SRB for the first path can be a non-separated bearer type SRB (e.g., non-separated SRB1 or non-separated SRB2) or a non-repeating separated bearer type SRB (e.g., non-repeating separated SRB1 or non-repeating separated SRB2).

[0195] In the example, the configuration also includes PDCP information indicating the SRB type to be used for the SRB when / when one or more triggering events are determined to have occurred, or afterward. The PDCP information may include at least one of the following: PDCP repeat configuration information (e.g., as mentioned above regarding...). Figure 3 , Figure 4 and Figure 5 The PDCP duplication discussed here is used to configure the UE to activate PDCP duplication after determining that one or more triggering events have occurred; PDCP switching configuration information (e.g., as mentioned above regarding...) Figure 3 , Figure 4 and Figure 5 The PDCP-switch discussed here is used to configure the UE to switch the SRB to the second path after determining that one or more triggering events have occurred; PDCP configuration information (e.g., as mentioned above regarding...) Figure 3 , Figure 4 and Figure 5 The PDCP-config1 discussed herein is used to indicate to the UE the type of SRB to be used for the SRB after the configuration of the SRB on the second path has been completed, or when or after the occurrence of one or more triggering events is determined.

[0196] When the second path is an indirect path, gNB 106 can send configuration information to relay UE 110 for configuring SRBs (e.g., SRB1 or SRB2) on the second path. For example, gNB 106 can send this configuration information separately to relay UE 110 (in its configuration as a relay UE).

[0197] Still referencing Figure 9 This is a flowchart illustrating the steps of a method 900 for managing multipath communication in a wireless communication system according to one or more embodiments of the present invention. The wireless communication system supports multipath communication and relay between a UE and a network. The wireless communication system supports sidelink relay and / or other point-to-point relay, such as via WiFi relay or Bluetooth relay. In the case where the wireless communication system supports sidelink relay, the UE is referred to as a remote UE, and the relay node is referred to as a relay UE (e.g., a UE operating or functioning as a relay). The network of the wireless communication system includes at least one base station. Method 900 is performed at the relay node. The UE is connected to the base station via a direct path, and an indirect path including the relay node is to be established between the UE and the base station. Regarding... Figure 1a In the example shown, the relay node performing method 900 can be a relay node or relay UE 110, the UE can be a remote UE 113, and the base station can be base station 106 (also referred to as gNB 106). Figure 9 The image shown and about Figure 9 The described method 900 can be performed by software elements and / or hardware elements. Therefore, for example, as... Figure 9 The image shown and about Figure 9 The described method can be performed by a device for a UE, the device including one or more processing units configured to execute the method. The UE can, for example... Figure 6 The images and references shown Figure 6 The communication device 600 described is implemented therein, wherein, as Figure 9 The image shown and about Figure 9 The described method is performed by one or more processing units (such as processing unit 611, etc.).

[0198] In summary, at step 902, the relay UE 110 sends information to the remote UE 113 or the gNB 106 indicating that the relay node is a version 18 relay node or a higher / later version (version 18+) relay node (e.g., to indicate to the remote UE or gNB whether the relay UE 110 can be triggered to enter the RRC connected state in response to any version 18 or later process). The information sent by the relay UE 110 may include capability information indicating the capabilities of the relay UE 110 associated with a version 18 or higher relay node: for example, this information may include the capability that can be used to determine whether the relay UE 110 supports being triggered by the remote UE 113 to enter RRC_CONNECTED (e.g., the relay UE 110 supports PC5 triggering). In other words, this information may include the capabilities of relay UE 110, which can be used to determine whether relay UE 110 is a relay node of 3GPP version 18+ (e.g., 5G ProSe capability, multipath capability, AccessStratumReleaseSidelink field set to rel18). Remote UE 113 and gNB 106 use this information to identify whether relay UE 110 is a relay node of 3GPP version 18 or later. If relay UE 110 is not identified as a relay node of 3GPP version 18 or later based on the information sent by relay UE 110, backward compatibility issues are determined, and as referenced above. Figure 5 The example message flow discussed can be used to resolve backward compatibility issues (e.g., where a version 17 procedure would be required to trigger relay UE 110 into the RRC_CONNECTED state, which may involve using RRC messages or NAS messages).

[0199] When relay UE 110 sends information to gNB 106, relay UE 110 can complete the registration phase (e.g., Figure 5 (501) Sends information (such as 5G ProSe capability) to gNB 106 and / or other capabilities that may be used to determine whether relay UE 110 supports entering RRC_CONNECTED triggered by remote UE 113 (e.g., relay UE 110 supports PC5 triggering).

[0200] When relay UE 110 sends information to remote UE 113, relay UE 110 may include it in the SIB message (broadcast by relay UE 110) as... Figure 5Information is sent to the remote UE 113 in the discovery message as part of the discovery process 502, in the RRC message during PC5 establishment (between remote UE 113 and relay UE 110), or in the UECapabilityInformationSidelink message (e.g., setting the AccessStratumReleaseSidelink field to rel18 in UECapabilityInformationSidelink). Information sent by the relay UE 110 can be sent in response to a request sent by the remote UE 113. For example, the remote UE 113 can send a UECapabilityEnquirySidelink message and can receive a UECapabilityInformationSidelink message in response that includes the capabilities of the relay UE 110 (such as whether the relay UE 110 supports entering RRC_CONNECTED triggered by the remote UE 113 (e.g., the relay UE 110 supports PC5 triggering)). The above is about... Figure 5 The discussion provides additional details for this example situation.

[0201] Figure 6 A schematic representation of an example wireless communication device (apparatus) according to one or more example embodiments of the present disclosure is shown.

[0202] The wireless communication device 600 is preferably a communication device capable of wireless communication, such as a microcomputer, workstation, mobile device, lightweight portable device, or fixed device. The communication device 600 includes a communication bus 613, which is preferably connected to:

[0203] - Processing unit 611, such as a microprocessor, and Figure 6 The CPU is referred to as the CPU in the diagram. The processing unit 611 may be a single processing unit or processor, or it may include two or more processing units or processors that perform the processing required to operate the communication device 600. The number of processors and the allocation of processing functions to the central processing unit 611 are design choices for those skilled in the art.

[0204] - A memory for storing data and a computer program containing instructions for operating the communication device 600. The computer program may contain a number of different program elements (modules) or subroutines containing instructions for various operations and for implementing methods according to one or more embodiments of the invention. For example, a program element includes at least one element for managing the use of SRBs as discussed above. At least one element, when executed by the central processing unit 611, configures one or more processing units (e.g., as processing unit 611 or part of processing unit 611) to perform the methods described above (one or more).

[0205] The communication device 600 may further include at least one communication interface 602 for communication with a wireless communication system (e.g., Figure 1a It communicates with other devices or nodes in a wireless communication system. At least one communication interface 602 can be connected to a communication network 603, such as the radio access network of the wireless communication system, on which digital data packets or frames or control frames are transmitted.

[0206] Each of the relay nodes and multiple nodes (e.g., remote UEs and network nodes) in the communication system 100 may include such a communication device 600.

[0207] The memory may include:

[0208] - Read-only memory 607, denoted as ROM, is used to store computer programs for implementing methods according to one or more embodiments of the present invention;

[0209] - Random access memory 612, denoted as RAM, is used to store executable code of a method according to one or more embodiments of the present invention, and registers adapted to record variables and parameters required to implement a method according to one or more embodiments of the present invention.

[0210] Optionally, the communication device 600 may also include one or more of the following components:

[0211] - A data storage component 604, such as a hard disk, for storing a computer program for implementing a method according to one or more embodiments of the present invention;

[0212] - Disk drive 605 for disk 606, the disk drive being adapted to read data from disk 606 or write data to disk;

[0213] - Screen 609 is used to display the decoded data and / or serves as a graphical interface with the user using keyboard 610 or any other user input component.

[0214] Preferably, the communication bus provides communication and interoperability between various elements included in or connected to the communication device 600. The representation of the bus is not limiting, and in particular, the processing unit is operable to instruct any element of the communication device 600 to communicate directly or by means of another element of the communication device 600.

[0215] Disk 606 may optionally be replaced by any information medium (e.g., a rewritable or non-rewritable compact disc (CD-ROM), ZIP disk, USB key, or memory card, etc.), and generally, it may be replaced by an information storage component that can be read by a microcomputer or microprocessor, integrated or not integrated into a communication device, may be removable, and adapted to store one or more programs (the execution of which enables the methods according to embodiments of the invention to be performed).

[0216] Executable code may optionally be stored in read-only memory 607, on hard disk 604, or on removable digital media (e.g., disk 606 as described above). According to an optional variation, the executable code of the program may be received via communication network 603, through interface 602, and stored in one of the storage components of communication device 600 (such as hard disk 604) before being executed.

[0217] Processing unit 611 is preferably adapted to control and guide the execution of instructions or portions of software code according to one or more programs based on the invention, these instructions being stored in one of the aforementioned storage components. The instructions can be executed by one or more processors such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Therefore, the terms "processor" or "processing unit" as used herein can refer to any of the foregoing structures or any other structure suitable for implementing the techniques described herein. Furthermore, these techniques can be implemented entirely within one or more circuit or logic elements.

[0218] In this embodiment, the device is a programmable device that implements the invention using software. However, alternatively, the invention can be implemented in hardware (e.g., in the form of an application-specific integrated circuit or ASIC). In this case, the logic units of the device are configured to perform the steps of the method (one or more) described above according to the invention.

[0219] While the invention has been described with reference to embodiments, it should be understood that the invention is not limited to the disclosed embodiments. Those skilled in the art will understand that various changes and modifications can be made without departing from the scope of the invention as defined in the appended claims. All features disclosed in this specification (including any appended claims, abstract, and drawings) and / or all steps of any method or process so disclosed can be combined in any combination other than at least some mutually exclusive combinations of such features and / or steps. Unless expressly stated otherwise, the features disclosed in this specification (including any appended claims, abstract, and drawings) can be replaced by alternative features serving the same, equivalent, or similar purpose. Therefore, unless expressly stated otherwise, the disclosed features are merely one example of equivalent or similar features in a general series.

[0220] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude plural. The fact that different features are defined only in mutually different dependent claims does not mean that combinations of these features cannot be used advantageously.

[0221] In the foregoing embodiments, the functions can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted through a computer-readable medium as one or more instructions or code, and executed by a hardware-based processing unit.

[0222] Computer-readable media may include: computer-readable storage media, which correspond to tangible media such as data storage media; or communication media, which include any medium that facilitates, for example, the transfer of a computer program from one place to another according to a communication protocol. In this way, computer-readable media may generally correspond to (1) a non-transitory tangible computer-readable storage medium or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available medium that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and / or data structures to implement the techniques described in this disclosure. Computer program products may include computer-readable media.

[0223] By way of example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage units, disk storage units, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible by a computer. Furthermore, any connection is appropriately referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but rather refer to non-transient tangible storage media. As used herein, disks (and discs) include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, wherein a disk typically magnetically reproduces data, while a disc optically reproduces data using lasers. The above combinations should also be included within the scope of computer-readable media.

Claims

1. A method for managing multipath communication in a wireless communication system, said wireless communication system supporting multipath communication and relay between a user equipment (UE) and a network including base stations, wherein, The UE is connected to the base station via a direct path, and wherein, to establish an indirect path between the UE and the base station including a relay node, the method includes, at the relay node: Send information to the UE or the base station indicating whether the relay node supports PC5 triggering to enter the RRC_CONNECTED state.

2. The method according to claim 1, wherein, Sending includes: Send information to the UE or the base station instructing the relay node to support PC5 triggering to enter the RRC_CONNECTED state.

3. The method according to claim 2, wherein, The information indicates that the relay node is a version 18 relay node or a version higher than version 18.

4. The method according to claim 1 or 2, wherein, The information includes capability information indicating the capabilities of the relay node, including the PC5 triggering capability indicating whether the relay node supports PC5 triggering to enter the RRC_CONNECTED state.

5. The method according to claim 1 or 2, wherein, The information includes capability information indicating the capabilities of relay nodes associated with relay nodes of version 18 or higher, including PC5 triggering capability indicating whether the relay node supports PC5 triggering to enter the RRC_CONNECTED state.

6. The method according to any one of claims 1 to 5, wherein, The information sent to the base station is included in one of the following: Registration request message; RRC message; RRCSetupRequest message.

7. The method according to any one of claims 1 to 5, wherein, The information sent to the UE is included in one of the following: SIB message; Discover message; RRC message when PC5 is established; UECapabilityInformationSidelink message.

8. The method according to any one of claims 1 to 5 and claim 7, wherein, The information is sent to the UE in response to a request received from the UE.

9. The method according to any one of claims 1 to 8, further comprising: Receive configuration information from the base station for configuring the SRB on the indirect path.

10. A method for managing the use of signaling radio bearers (SRBs) in a wireless communication system that supports multipath communication and relay between a user equipment (UE) and a network including base stations, the method comprising at the UE: Activate the SRB on the first path between the UE and the base station; The system receives configuration information from the base station for configuring the SRB on a second path between the UE and the base station. The configuration information includes trigger event information for indicating one or more triggering events for triggering the use of the SRB on the second path. After determining that one or more of the triggering events has occurred, the second path is used to carry signaling data through the SRB. The first path is one of a direct path between the UE and the base station and an indirect path between the UE and the base station including a relay node, and the second path is one of a direct path and an indirect path.

11. The method according to claim 10, wherein, The one or more triggering events include at least one of the following: The first path becomes inactive for one or more events; One or more events occur on the link of the first path where a link problem occurs; Backward compatibility events.

12. The method according to claim 11, wherein, The one or more events that make the first path inactive include at least one of the following: The change of the first path; Release of the first path; The handover of the first path; Deactivation of the first path; Relay (re)selection of relay nodes when the first path is an indirect path; Relay handover of relay nodes when the first path is an indirect path.

13. The method according to claim 11 or 12, wherein, The one or more events in which a link problem occurs on the link of the first path include at least one of the following: Radio link failure (RLF) on the first path link; Link degradation on the first path; Fault configuration for the first path.

14. The method according to claim 13, wherein, When the first path is an indirect path including relay nodes between the UE and the base station, the one or more events of a link problem occurring on the link of the first path include at least one of the following: RLF on the link between the relay node and the base station; RLF on the link between the UE and the relay node.

15. The method according to any one of claims 11 to 14, wherein, The backward compatibility event includes one of the following: An event where a relay node is not identified as a version 18 relay node or is not identified as a relay node of a version higher than version 18; An event where a relay node is in a disconnected RRC state and is not identified as a relay node of version 18 or higher.

16. The method according to any one of claims 10 to 15, further comprising: Receive a message from the base station including reconfiguration information for reconfiguring the UE, the reconfiguration information indicating one of the following: The change of the first path, Release of the first path, The handover of the first path, Deactivation of the first path Relay (re)selection, Relay handover; In the case where one or more triggering events include one or more events where the first path becomes inactive, the occurrence of one or more of the triggering events is determined from the received reconfiguration information.

17. The method according to any one of claims 10 to 16, wherein, The one or more triggering events include backward compatibility events, wherein the first path is a direct path or an indirect path, and the second path is an indirect path between the UE and the base station including a relay node, and the method further includes: After determining backward compatibility issues with the relay node, the SRB is activated on the second path and the second path is used to send a message to the relay node via the SRB to trigger the relay node to enter the RRC_CONNECTED state.

18. The method of claim 17, further comprising: Receive information from the relay node in the indirect path, or from the base station, indicating that the relay node is not identified as a relay node of version 18 or is not identified as a relay node of a version higher than version 18; Backward compatibility issues with the relay node are determined by determining, based on the received information, that the relay node in the indirect path is not identified as a version 18 relay node or is not identified as a relay node of a version higher than version 18.

19. The method of claim 17, further comprising: The base station receives information indicating that the relay node in the indirect path is in a disconnected RRC state and is not identified as a relay node of version 18 or higher. Backward compatibility issues with the relay node are determined by determining, based on the received information, that the relay node is in a disconnected RRC state and is not identified as a version 18 relay node or a relay node of a version higher than version 18.

20. The method according to any one of claims 10 to 19, wherein, The SRB activated for the first path is one of the following: SRBs of non-separate bearing type; SRBs with non-repeating, separate bearer types.

21. The method according to any one of claims 10 to 20, wherein, The configuration information also includes PDCP information, which indicates the type of SRB to be used for the SRB when or after determining that one or more of the triggering events have occurred.

22. The method according to claim 21, wherein, If the activated SRB on the first path is a non-separate bearer type SRB or a non-repeating separate bearer type SRB, the following is used: After determining that one or more of the triggering events has occurred, the type of SRB to be configured on the second path is determined based on the PDCP information.

23. The method according to claim 21 or 22, wherein, The PDCP information includes at least one of the following: PDCP repetition configuration information is used to configure the UE to activate PDCP repetition after determining the occurrence of one or more triggering events; PDCP handover configuration information is used to configure the UE to switch the SRB to the second path after determining that one or more of the triggering events have occurred; PDCP configuration information is used to indicate to the UE the SRB type to be used for the SRB after the SRB has been configured on the second path, or when or after determining the occurrence of one or more triggering events.

24. The method according to any one of claims 10 to 23, wherein, When the activated SRB on the first path is a non-detached bearer type SRB, the following is used: After determining that one or more of the triggering events have occurred, the SRB is switched to the second path and the second path is used to carry signaling data through the SRB.

25. The method according to any one of claims 10 to 23, wherein, In the case that the activated SRB on the first path is a non-repeating, separate bearer type SRB, the following is used: After determining that one or more of the triggering events have occurred, the SRB is activated on the second path and the second path is used to carry signaling data through the SRB.

26. The method according to any one of claims 10 to 23, wherein, When the activated SRB on the first path is a non-detached bearer type SRB, the following is used: After determining that one or more of the triggering events have occurred, the type of the SRB for the second path is changed to a separate bearer type with or without repetition, the SRB is switched to the second path, and the second path is used to carry signaling data through the SRB.

27. The method according to any one of claims 10 to 23, wherein, In the case that the activated SRB on the first path is a non-repeating, separate bearer type SRB, the following is used: After determining that one or more of the triggering events have occurred, the type of the SRB for the second path is changed to a repeating split bearer type, and the second path is used to carry signaling data through the SRB.

28. The method according to any one of claims 10 to 27, further comprising: After determining that one or more of the triggering events has occurred and using the second path, the SRB is deactivated on the first path.

29. The method according to any one of claims 10 to 28, wherein, The first path is a direct path between the UE and the network, and the method further includes: After determining that one or more of the triggering events has occurred and using the second path, the first path is deactivated; The SRB is reactivated on the first path or the other direct path after communication on the first path is re-established or after communication on another direct path between the UE and the network is established.

30. The method according to claim 29, wherein, The configuration information also includes PDCP configuration information for instructing the UE on the SRB type to be used for the SRB after the SRB has been configured on the second path, wherein reactivating the SRB includes: reactivating the SRB on the first path or the other direct path based on the SRB type indicated in the PDCP configuration information.

31. A method for managing the use of signaling radio bearers (SRBs) in a wireless communication system that supports multipath communication and relay between a user equipment (UE) and a network including a base station, the method comprising at the base station: Send configuration information to the UE for configuring SRB on the first path between the UE and the base station; The configuration information for configuring the SRB on a second path between the UE and the base station is sent to the UE. The configuration information includes trigger event information for indicating one or more triggering events for triggering the use of the SRB on the second path. Using the second path, signaling data is received from the UE via the SRB. The first path is one of a direct path between the UE and the base station and an indirect path between the UE and the base station including a relay node, and the second path is one of a direct path and an indirect path.

32. The method according to claim 31, wherein, The one or more triggering events include at least one of the following: The first path becomes inactive for one or more events; One or more events occur on the link of the first path where a link problem occurs; Backward compatibility events.

33. The method according to claim 32, wherein, The one or more events that make the first path inactive include at least one of the following: The change of the first path; Release of the first path; The handover of the first path; Deactivation of the first path; Relay (re)selection of relay nodes when the first path is an indirect path; Relay handover of relay nodes when the first path is an indirect path.

34. The method according to claim 32 or 33, wherein, The one or more events in which a link problem occurs on the link of the first path include at least one of the following: Radio link failure (RLF) on the first path link; Link degradation on the first path; Fault configuration for the first path.

35. The method according to claim 34, wherein, When the first path is an indirect path including relay nodes between the UE and the base station, the one or more events of a link problem occurring on the link of the first path include at least one of the following: RLF on the link between the relay node and the base station; RLF on the link between the UE and the relay node.

36. The method according to any one of claims 32 to 35, wherein, The backward compatibility event includes one of the following: An event where a relay node is not identified as a version 18 relay node or is not identified as a relay node of a version higher than version 18; An event where a relay node is in a disconnected RRC state and is not identified as a relay node of version 18 or higher.

37. The method according to any one of claims 31 to 36, further comprising: After determining to reconfigure the first path, a message including reconfiguration information for reconfiguring the UE is sent to the UE, the reconfiguration information indicating one of the following: The change of the first path; Release of the first path; The handover of the first path; Deactivation of the first path; Relay (re)selection; Relay handover.

38. The method according to any one of claims 31 to 37, wherein, The first path is a direct path or an indirect path, and the second path is an indirect path between the UE and the base station, including a relay node. The method further includes: Receive information associated with the capabilities of the relay node; Based on the received information, identify whether the relay node is a relay node of version 18 or a relay node of a version higher than version 18; After the relay node is not identified as a relay node of version 18 or higher, information indicating that the relay node is not identified as a relay node of version 18 or is not identified as a relay node of a version higher than version 18 is sent to the UE.

39. The method according to claim 38, wherein, The information received at the base station was sent by the relay node and is included in one of the following: Registration request message; RRC message; RRCSetupRequest message.

40. The method according to any one of claims 31 to 39, wherein, The configuration information for configuring the SRB on the first path includes configuration information for configuring the SRB for the first path as one of the following SRBs: SRBs of non-separate bearing type; SRBs with non-repeating, separate bearer types.

41. The method according to any one of claims 31 to 40, wherein, The configuration information for configuring the SRB on the second path also includes PDCP information, which indicates the type of SRB to be used for the SRB when or after determining the occurrence of one or more triggering events.

42. The method according to claim 41, wherein, The PDCP information includes at least one of the following: PDCP repetition configuration information is used to configure the UE to activate PDCP repetition after determining the occurrence of one or more triggering events; PDCP handover configuration information is used to configure the UE to switch the SRB to the second path after determining that one or more of the triggering events have occurred; PDCP configuration information is used to indicate to the UE the SRB type to be used for the SRB after the SRB has been configured on the second path, or when or after determining the occurrence of one or more triggering events.

43. The method according to any one of claims 31 to 42, wherein, When the second path is an indirect path between the UE and the base station, including a relay node, the method further includes: The relay node is sent configuration information for configuring the SRB on the second path.

44. An apparatus for a user equipment, i.e., a UE, the apparatus comprising: One or more processing units are configured to perform the method according to any one of claims 1 to 30.

45. An apparatus for a base station, the apparatus comprising: One or more processing units are configured to perform the method according to any one of claims 31 to 43.

46. ​​A computer program comprising instructions that, when executed by a computer, cause the computer to perform the control method according to any one of claims 1 to 43.

47. A computer-readable medium carrying a computer program according to claim 46.

Images