COMMUNICATION METHOD, APPARATUS AND COMPUTER STORAGE MEDIUM

Abstract

The embodiments of the present disclosure relate to a method, an apparatus, and a computer-readable medium for communication. A first apparatus receives an RRC reconfiguration message from a second apparatus serving the first apparatus, and determines whether the RRC reconfiguration message includes information about a path switch to a third apparatus. The first apparatus communicates with a fourth apparatus serving the third apparatus via the third apparatus, and communicates with the third apparatus via a sidelink interface. If the RRC reconfiguration message includes the information, the first apparatus determines the configuration of the first apparatus for path switch based on a type of path switch. In this way, it is possible to provide a procedure for path switch to a relay UE.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE

[0002] Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to a communication method, apparatus, and computer storage medium for sidelink relays. [Background technology]

[0002] In the context of New Radio (NR) sidelink relay, a user equipment (UE) that communicates with a gNB via another UE in the coverage (IC) of the gNB is called a remote UE, and the other UE is called a relay UE. A remote UE may be out of coverage (OoC) of the gNB or in the coverage of the gNB. A connection is established between the remote UE and the relay UE via a sidelink.

[0003] The study of sidelink relay needs to specify a mechanism for service continuity, including direct-indirect path switching or indirect-indirect path switching. Direct path means that there is no relay UE between the remote UE and the gNB, and indirect path means that there is a relay UE between the remote UE and the gNB. For direct-indirect path switching or indirect-indirect path switching, the realization for path switching is still incomplete and awaits further research. Summary of the Invention [Problem to be solved by the invention]

[0004] In general, the exemplary embodiments of the present disclosure provide a communication method, apparatus, and computer storage medium for path switching in a sidelink relay. [Means for solving the problem]

[0005] In a first aspect, a method of communication is provided, the method including: receiving, at a first device, a radio resource control (RRC) reconfiguration message from a second device serving the first device, determining whether the RRC reconfiguration message includes information regarding a path switch to a third device, the first device communicating with a fourth device serving the third device via the third device and communicating with the third device via a sidelink interface, and determining a configuration of the first device for the path switch according to a determination that the RRC reconfiguration message includes the information based on a type of the path switch.

[0006] In a second aspect, a method of communication is provided, the method comprising: transmitting, in a second device, an RRC reconfiguration message including information regarding a path switch to a third device to a first device served by the second device, the first device communicating via the third device with a fourth device serving the third device and communicating with the third device via a sidelink interface.

[0007] In a third aspect, a method of communication is provided, the method including: receiving, at a third device, an RRC reconfiguration complete message from a first device, forwarding the RRC reconfiguration complete message to a fourth device, the first device communicating with the fourth device via the third device and communicating with the third device via a sidelink interface, and sending to the first device a fourth indication regarding the RRC reconfiguration complete message.

[0008] In a fourth aspect, there is provided an apparatus for communications, said apparatus comprising a processor configured to perform a method according to the first or third aspect of the present disclosure.

[0009] In a fifth aspect, there is provided an apparatus for communications, said apparatus comprising a processor configured to perform a method according to the second aspect of the present disclosure.

[0010] In a sixth aspect, there is provided a computer readable medium storing instructions that, when executed on at least one processor, cause the at least one processor to perform a method according to the first or third aspect of the present disclosure.

[0011] In a seventh aspect, a computer readable medium is provided having instructions stored thereon that, when executed on at least one processor, cause the at least one processor to perform a method according to the second aspect of the present disclosure.

[0012] Other features of the present disclosure will become readily apparent from the following description. [Brief description of the drawings]

[0013] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of several embodiments of the present disclosure in the accompanying drawings.

[0014] [Figure 1A] FIG. 1 illustrates an example communication network in which some embodiments of the present disclosure may be implemented.

[0015] [Figure 1B] FIG. 2 is a schematic diagram illustrating a user plane protocol stack in which some embodiments of the present disclosure may be implemented.

[0016] [Figure 1C] FIG. 2 is a schematic diagram illustrating a control plane protocol stack in which some embodiments of the present disclosure may be implemented.

[0017] [Figure 1D]FIG. 1 is a schematic diagram illustrating a control plane protocol stack for a sidelink control channel (SCCH) for PC5-radio resource control (PC5-RRC) in which some embodiments of the present disclosure can be implemented.

[0018] [Figure 1E] FIG. 1 is a schematic diagram illustrating a control plane protocol stack for SCCH for PC5-signaling (PC5-S) in which some embodiments of the present disclosure can be implemented.

[0019] [Diagram 2] FIG. 2 is a schematic diagram of a communication process for path switching according to an embodiment of the present disclosure.

[0020] [Diagram 3] 4 is a flowchart for an exemplary communication method implemented in a first device, according to some embodiments of the present disclosure.

[0021] [Figure 4] 11 is a flowchart for an example communication method implemented in a second device, according to some embodiments of the present disclosure.

[0022] [Diagram 5] 11 is a flowchart for an example communication method implemented in a third device, according to some embodiments of the present disclosure.

[0023] [Figure 6] FIG. 1 is a schematic block diagram of an apparatus suitable for implementing embodiments of the present disclosure.

[0024] In the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The principles of the present disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are provided for illustrative purposes only, to assist those skilled in the art in understanding and implementing the present disclosure, and do not imply any limitations on the scope of the present disclosure. The disclosure described herein can be implemented in various ways different from those described below.

[0026] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0027] As used herein, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include User Equipment (UE), personal computers, desktops, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, Ultra-Reliable Low Latency Communication (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, vehicle-mounted devices for V2X communications where X stands for pedestrian, vehicle, or infrastructure / network, devices for integrated access and integrated access and backhaul (IAB), satellite-based or airborne vehicles in a non-terrestrial network (NTN) including High Altitude Platforms (HAPs) including satellites and Unmanned Aircraft Systems (UASs), extended reality (XR) devices including different types of reality such as augmented reality (AR), mixed reality (MR), virtual reality (VR), unmanned aerial vehicles (UAVs), which are aircraft without a human pilot and commonly referred to as drones. "Terminal Device" includes, but is not limited to, a vehicle (V2X), a device on a high speed train (HST), or an image capture device such as a digital camera, a sensor game device, a music storage and playback device, or an Internet appliance that allows wireless or wired Internet access and browsing, etc. The "Terminal Device" may further have "multicast / broadcast" capabilities to support V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, over-the-air software distribution, group communication, and IoT applications that are public safety and mission critical. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs.The term "terminal equipment" may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless equipment.

[0028] The term "network device" refers to a device capable of providing or hosting a cell or coverage in which a terminal device can communicate. Examples of network devices include, but are not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a transmit / receive point (TRP), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an IAB node, a femto node, a pico node, a low power node such as a reconfigurable intelligent surface (RIS), etc.

[0029] The terminal device or network device may have the capability of artificial intelligence (AI) or machine learning. Generally, it includes a model trained from a large amount of data collected for a specific function and can be used to predict some information.

[0030] The terminal device or network device may operate on several frequency ranges, such as FR1 (410 MHz-7125 MHz), FR2 (24.25 GHz-71 GHz), frequency bands greater than 100 GHz, and Tera Hertz (THz). It can also operate on licensed / unlicensed / shared spectrum. The terminal device may have two or more connections with the network device under Multi-Radio Dual Connectivity (MR-DC) application scenarios. The terminal device or network device can operate in full duplex, flexible duplex, and cross division duplex modes.

[0031] Embodiments of the present disclosure may be implemented in test equipment, such as, for example, a signal generator, a signal analyzer, a spectrum analyzer, a network analyzer, a test terminal equipment, a test network equipment, a channel emulator, and the like.

[0032] In one embodiment, the terminal device can connect to a first network device and a second network device. One of the first network device and the second network device may be a master node and the other may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In one embodiment, the first network device may be a first RAT device and the second network device may be a second RAT device. In one embodiment, the first RAT device is an eNB and the second RAT device is a gNB. Information about the different RATs may be transmitted from at least one of the first network device or the second network device to the terminal device. In one embodiment, the first information may be transmitted from the first network device to the terminal device, and the second information may be transmitted from the second network device to the terminal device directly or via the first network device. In one embodiment, information about the configuration of the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information regarding the reconfiguration of the terminal device configured by the second network device may be transmitted from the second network device directly to the terminal device or via the first network device.

[0033] As used herein, the singular forms "a," "an," and "said" include the plural forms unless the context clearly indicates otherwise. The term "comprises" and variations thereof should be understood as open-ended terms meaning "including, but not limited to." The term "based on" should be understood as "based at least in part on." The terms "one embodiment" and "embodiment" should be understood as "at least one embodiment." The term "another embodiment" should be understood as "at least one other embodiment." Terms such as "first," "second," and the like may refer to different or the same object. The following may include other explicit and implicit definitions.

[0034] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to illustrate that selections can be made from among many functional alternatives used, and that such selections are not necessarily better, smaller, higher, or otherwise more preferred than other selections.

[0035] In the context of this application, the term "remote UE" refers to a terminal device that communicates with a network device via another terminal device within the coverage of the network device. The term "relay UE" refers to a terminal device that is within the coverage of a network device, through which the remote UE communicates with the network device. The relay UE is connected with the remote UE via a sidelink interface, such as a PC5 interface. The term "remote UE" may be used interchangeably with remote terminal device or remote device. The term "relay UE" may be used interchangeably with relay terminal device or relay device.

[0036] For service continuity, in some scenarios, a remote UE may be switched from communicating directly with a gNB to communicating indirectly with a gNB via a relay UE, which is referred to as direct-indirect path switching. In some scenarios, a remote UE may be switched from communicating indirectly with a gNB via a relay UE to communicating indirectly with a gNB via another relay UE, which is referred to as indirect-indirect path switching. For these scenarios, a path switch to a relay UE needs to be realized.

[0037] The embodiment of the present disclosure provides a solution for initiating a path switch to a relay UE. In this solution, in response to receiving an RRC reconfiguration message from a gNB, a remote UE determines whether the RRC reconfiguration message includes information on a path switch to a relay UE. If the RRC reconfiguration message includes information on a path switch to a relay UE, the remote UE starts a timer configured for a path switch. Thus, a path switch to a relay UE may be identified and initiated.

[0038] The principles and embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Communication Network Example

[0039] FIG. 1 is a schematic diagram of an exemplary communication network 100 in which an embodiment of the present disclosure can be implemented. As shown in FIG. 1, the communication network 100 may include a first device 110, a second device 120, a third device 130, another third device 131, and a fourth device 140. The second device 120 provides a cell 121 serving one or more devices, and the fourth device 140 provides a cell 141 serving one or more devices. In the example of FIG. 1, the third device 110 may be located in the cell 141 of the fourth device 140 and may directly communicate with the fourth device 140. The other third device 131 may be located in the cell 121 of the second device 120 and may directly communicate with the second device 120.

[0040] In some cases, when the first device 110 is located within the cell 121, the first device 110 may directly communicate with the second device 120. When the first device 110 is located outside or inside the cell 121, the first device 110 may communicate with the second device 120 via the other third device 131. Similarly, when the first device 110 is located within the cell 141, the first device 110 may also directly communicate with the fourth device 140. When the first device 110 is located outside or inside the cell 141, the first device 110 may communicate with the fourth device 140 via the third device 130. In these cases, the first device 110 may correspond to a remote UE, and the third device 130 or another third device 131 may correspond to a relay UE.

[0041] In some embodiments, the first device 110 and the second device 120 may communicate with each other via a channel, such as a wireless communication channel. The wireless communication channel may include a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a physical random-access channel (PRACH), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), and a physical broadcast channel (PBCH). Of course, any other suitable channel is also possible. Similarly, the first device 110 and the fourth device 140 may communicate with each other.

[0042] In some embodiments, the first device 110 and the third device 130 may communicate with each other via a sidelink channel, such as a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), a physical sidelink feedback channel (PSFCH), a physical sidelink broadcast channel (PSBCH), etc. For example, a PC5 link or a PC5 RRC connection may be established between the first device 110 and the third device 130. Similarly, the first device 110 and the further third device 131 may also communicate with each other.

[0043] Communications in the communications network 100 may conform to any suitable standard, including, but not limited to, Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), New Radio (NR), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC), and the like. Furthermore, communications may be performed according to any generation of communications protocols now known or developed in the future. Embodiments of the present disclosure may be performed according to any generation of communications protocols now known or developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

[0044] It should be understood that the number of devices in Figure 1 is given for illustrative purposes and does not imply any limitations to the present disclosure. Communications network 100 may include any suitable number of first devices, second devices, third devices, or fourth devices suitable for implementing embodiments of the present disclosure.

[0045] For purposes of illustration, the first device 110, the third device 130, and the further third device 131 are shown as terminal devices, and the second device 120 and the fourth device 140 are shown as network devices. For purposes of explanation only, and without implying any limitation to the scope of the present disclosure, some embodiments are described in the context of the first device 110, the third device 130, and the further third device 131 being terminal devices, and the second device 120 and the fourth device 140 being network devices.

[0046] It should be understood that in other embodiments, the first device 110 and / or the third device 130 and / or the other third device 131 may be network devices, and the second device 120 and / or the fourth device 140 may be terminal devices. In other words, the principles and spirit of the present disclosure are applicable to both uplink transmission and downlink transmission. Furthermore, in some embodiments, the first device 110, the second device 120, the third device 131, and the fourth terminal device 140 may all be terminal devices, and in some embodiments, the first device 110, the second device 120, the third device 140, the other third device 131, and the fourth device 140 may all be network devices. The present application does not limit this aspect.

[0047] The communication between the terminal device and the network device in the communication network 100 may be performed according to a user plane and a control plane protocol stack. Generally speaking, for a communication device (e.g., a terminal device or a network device), there may be multiple entities of multiple network protocol layers in the protocol stack, and these entities may be configured to perform corresponding processes on data or signaling sent from and received by the communication device. FIG. 1B is a schematic diagram 100B illustrating network protocol layer entities that may be established for a user plane protocol stack in an apparatus according to some embodiments of the present disclosure. For illustrative purposes, the first device 110 is hereinafter described as an example of a terminal device, and the second device 120 is hereinafter described as an example of a network device.

[0048] 1B, in the user plane, each of the first device 110 and the second device 120 may include an L1 layer entity, i.e., a physical (PHY) layer entity (also referred to as a PHY entity), and one or more entities of higher layers (L2 layer and L3 layer, i.e., higher layers), including a medium access control (MAC) layer entity (also referred to as a MAC entity), an RLC layer entity (also referred to as an RLC entity), a packet data convergence protocol (PDCP) layer entity (also referred to as a PDCP entity), and a service data application protocol (SDAP) layer entity (also referred to as an SDAP entity, which is established in 5G and subsequent generation networks). In some cases, the PHY, MAC, RLC, PDCP, and SDAP entities are in a stack structure.

[0049] FIG. 1C is a schematic diagram 100C illustrating network protocol layer entities that may be established for a control plane protocol stack in an apparatus according to some embodiments of the present disclosure. As shown in FIG. 1C, in the control plane, each of the first apparatus 110 and the second apparatus 120 may include an L1 layer entity, i.e., a PHY layer entity (also referred to as a PHY entity), and one or more entities of higher layers (L2 layer and L3 layer), including a MAC layer entity (also referred to as a MAC entity), an RLC layer entity (also referred to as an RLC entity), a PDCP layer entity (also referred to as a PDCP entity), and an RRC layer entity (also referred to as an RRC entity). The RRC layer may further be referred to as an access stratum (AS) layer, and therefore the RRC entity may further be referred to as an AS entity. As shown in FIG. 1C, the first apparatus 110 may further include a non-access stratum (NAS) layer entity (also referred to as a NAS entity). The NAS layer on the network side is located in a core network (CN, not shown) rather than in a network device. In some cases, these entities are stacked.

[0050] In general, a channel between the RRC layer and the PDCP layer is referred to as a radio bearer. A terminal device (e.g., the first device 110 or the third device 130) may be configured to have at least one data radio bearer (DRB) for carrying data plane data and at least one signaling radio bearer (SRB) for carrying control plane data. The RRC layer may be used interchangeably with the Uu RRC layer, the RRC entity, and the Uu RRC entity.

[0051] The communication between terminal devices in the communication network 100 may be performed according to a control plane protocol stack. Figure 1D is a schematic diagram 100D showing a control plane protocol stack for SCCH for PC5-RRC in which some embodiments of the present disclosure can be implemented. For illustrative purposes, the first device 110 and the third device 130 are described below as examples of terminal devices.

[0052] 1D, in the control plane, each of the first device 110 and the third device 130 may include an L1 layer entity, i.e., a PHY layer entity (also referred to as a PHY entity), and one or more entities of an upper layer (L2 layer and L3 layer, or an upper layer), including a MAC layer entity (also referred to as a MAC entity), an RLC layer entity (also referred to as an RLC entity), a PDCP layer entity (also referred to as a PDCP entity), and a PC5-RRC layer entity (also referred to as a PC5-RRC entity). In some cases, the PHY, MAC, RLC, PDCP, and PC5-RRC entities are in a stack structure.

[0053] In some embodiments, the RRC entity and the PC5-RRC entity may be the same entity (e.g., logical entity). Of course, the RRC entity and the PC5-RRC entity may be different entities (e.g., logical entities). In some embodiments, the RRC layer and the PC5-RRC layer may be implemented as the same layer. Of course, the RRC layer and the PC5-RRC layer may be implemented as different layers.

[0054] FIG. 1E is a schematic diagram 100E illustrating a control plane protocol stack for SCCH for PC5-S in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1E, in the control plane, each of the first device 110 and the third device 130 may include an L1 layer entity, i.e., a PHY layer entity (also referred to as a PHY entity), and one or more entities of upper layers (L2 layer and L3 layer), including a MAC layer entity (also referred to as a MAC entity), an RLC layer entity (also referred to as an RLC entity), a PDCP layer entity (also referred to as a PDCP entity), and a PC5-S layer entity (also referred to as a PC5-S entity). In some cases, the PHY, MAC, RLC, PDCP, and PC5-S entities are in a stack structure.

[0055] In general, the PC5-RRC layer may manage the PC5 RRC connection (e.g., establish / modify / release sidelink DRBs, (re)configure NR sidelink measurements and reporting, (re)configure sidelink CSI reference signal resources and CSI reporting delay bounds), and the PC5-S layer may manage the PC5 unicast link. In the context of the present disclosure, the PC5 RRC connection may be used interchangeably with the PC5 connection. The PC5 unicast link may be used interchangeably with the PC5 link, Layer 2 link on PC5, PC5 Layer 2 link, or Layer 2 link. The PC5-RRC layer may be used interchangeably with the PC5 RRC entity, PC5 RRC, PC5 RRC layer, PC5-RRC, AS layer, or lower layers of the PC5-S layer. The PC5-S layer may be used interchangeably with the PC5 signaling layer, the PC5 signaling sublayer, the V2X layer, the upper layer of the PC5-RRC layer, the upper layer of the RRC layer, or the NAS layer. The RRC layer may be used interchangeably with the Uu RRC layer, the RRC entity, or the AS layer. The RRC layer may be used interchangeably with a lower layer of the PC5-S layer.

[0056] Returning to FIG. 1A, in some scenarios, in an early stage, the first device 110 may communicate directly with the second device 120, or may communicate with the second device 120 via another third device 131. When the first device 110 moves, the first device 110 may need to switch routes to communicate with the fourth device 140 via the third device 130. It should be understood that the second device 120 and the fourth device 140 may be the same device. Of course, the second device 120 and the fourth device 140 may be different devices.

[0057] The embodiments of the present disclosure provide a solution to initiate a path switch for these scenarios, which will be described in detail below with reference to FIG. Example of route switching implementation

[0058] FIG. 2 is a schematic diagram of a communication process 200 for path switching according to an embodiment of the present disclosure. For illustrative purposes, the process 200 is described with reference to FIG. 1. The process 200 may involve a first device 110, a second device 120, a third device 130, and a fourth device 140 as shown in FIG. 1. The steps and the order of steps in FIG. 2 are merely for illustration and not for limitation. For example, the order of steps may be changed. Some of the steps may be omitted, or any other suitable additional steps may be added. In this example, the fourth device 140 serves the third device 130, and the second device 120 serves the first device 110. The first device 110 will be switched to communicate with the fourth device 140 via the third device 130, and the first device 110 will communicate with the third device 130 via a sidelink interface.

[0059] As shown in FIG. 2, the second device 120 may transmit an RRC reconfiguration message to the first device 110 (201). In some embodiments, the second device 120 may transmit the RRC reconfiguration message when the second device 120 determines to perform a handover procedure or a path switch for the first device 110. For example, the second device 120 may transmit the RRC reconfiguration message to the first device 110 when the second device 120 determines to perform an indirect-indirect path switch from the first device 110's communication via another third device 131 to the first device 110's communication via the third device 130. As another example, the second device 120 may transmit the RRC reconfiguration message to the first device 110 when the second device 120 determines to perform a direct-indirect path switch from the first device 110's direct communication to the first device 110's communication via the third device 130. As yet another example, when the second device 120 determines to perform a handover from direct communication between the first device 110 and the second device 120 to direct communication between the first device 110 and the fourth device 140, the second device 120 may send an RRC reconfiguration message to the first device 110.

[0060] It should be understood that the RRC reconfiguration message may be any suitable message for RRC reconfiguration, for example, the RRC reconfiguration message may be PC5-S signaling, PC5-RRC signaling, etc.

[0061] Upon receiving the RRC reconfiguration message, the first device 110 determines whether the RRC reconfiguration message includes information regarding path switching to the third device 130 (202). In other words, the first device 110 determines whether the RRC reconfiguration message indicates path switching to a relay UE. For example, the first device 110 may determine whether ReconfigurationWithSync in the RRC reconfiguration message includes information regarding path switching. It should be understood that the information regarding path switching may be conveyed in any other suitable manner.

[0062] In some embodiments, this information may include the identity (ID) of the third device 130. Based on the identity of the third device 130, the first device 110 can know that the path change to be performed is to a relay UE.

[0063] In some embodiments, this information may include an ID of the fourth device 140. Based on the identity of the fourth device 140, the first device 110 may determine whether the path switch is an intra-gNB path switch or an inter-gNB path switch.

[0064] In some embodiments, the information may include a setting of a timer for path switching. In other words, the timer is used for direct-indirect path switching or indirect-indirect path switching. That is, the timer is used for path switching to a relay UE, not for path switching to a network device. Therefore, the timer may be different from the existing timer T304 used for path switching to a network device. Based on the setting, the first device 110 may start a timer and determine whether path switching is successful or not. For example, if the timer expires, the first device 110 may determine that path switching is not successful and may initiate RRC re-establishment.

[0065] In some embodiments, the information may include an indication (for convenience, also referred to herein as the first indication) indicating a direct-to-indirect path switch or an indirect-to-indirect path switch. In other words, the first indication indicates a path switch to the relay UE, regardless of whether the path switch is a direct-to-indirect path switch or an indirect-to-indirect path switch.

[0066] In some embodiments, this information may include an indication of a direct-to-indirect path switch (also referred to herein as the second indication for convenience). In some embodiments, this information may include an indication of an indirect-to-indirect path switch (also referred to herein as the third indication for convenience). In this way, the first device 110 may know the type of path switch to be performed.

[0067] Upon determining that the RRC reconfiguration message includes information regarding path switching to the third device 130, the first device 110 determines (203) a configuration of the first device 110 for path switching. In some embodiments, if the RRC reconfiguration message does not include information regarding path switching to the third device 130, for example, if the RRC reconfiguration message includes information regarding handover to another network device, the first device 110 may determine a configuration of the first device 110 for handover. The present disclosure does not limit the configuration for handover and is intended to provide a solution for determining a configuration for path switching.

[0068] In some embodiments, the first device 110 may determine the path switch configuration based on a path switch type. The path switch type may include a direct-indirect path switch or an indirect-indirect path switch. In some embodiments, the first device 110 may determine the path switch type based on an explicit indication of the path switch type. For example, the explicit indication may be included in the information regarding the path switch. In some embodiments, the first device 110 may implicitly determine the path switch type based on an indication of the identity of the fourth device 140 and the identity of the second device 120.

[0069] In some embodiments, the first device 110 may determine a configuration of the first device 110 for path switching based on at least the ID of the fourth device 140 and the ID of the second device 120. In some embodiments, the ID of the fourth device 140 may include an ID of a gNB provided by the fourth device 140. In some embodiments, the ID of the fourth device 140 may include an ID of a cell group provided by the fourth device 140. In some embodiments, the ID of the fourth device 140 may include an ID of a special cell (SpCell) provided by the fourth device 140. In some embodiments, the ID of the second device 120 may include an ID of a gNB provided by the second device 120. For example, the gNB ID may be an integer having 22 bits or 32 bits. In some embodiments, the ID of the second device 120 may include an ID of a cell group provided by the second device 120. For example, the cell group ID may be an integer. In some embodiments, the ID of the second device 120 may include an ID of the SpCell provided by the second device 120. For example, the SpCell ID may be a physical cell ID (PCI), an NR cell identifier (NCI), an NR cell global identifier (NCGI), or a serving cell index. As another example, the SpCell ID may be an integer. Of course, any other suitable format for the SpCell ID is also possible.

[0070] In some embodiments, when the ID of the fourth device 140 includes a gNB ID and the second device 120 includes a gNB ID, if the IDs of the two gNBs are different, it is referred to as inter-gNB path switching, and if the IDs of the two gNBs are the same, it is referred to as intra-gNB path switching. In some embodiments, when the ID of the fourth device 140 includes a cell group ID and the second device 120 includes a cell group ID, if the IDs of the two cell groups are different, it is referred to as inter-cell group path switching, and if the IDs of the two cell groups are the same, it is referred to as intra-cell group path switching. In some embodiments, when the ID of the fourth device 140 includes a SpCell ID and the second device 120 includes a SpCell ID, if the IDs of the two SpCells are different, it is referred to as inter-SpCell path switching, and if the IDs of the two SpCells are the same, it is referred to as intra-SpCell path switching. Inter-gNB route switching may be used interchangeably with inter-cell group route switching or inter-SpCell route switching. Intra-gNB route switching may be used interchangeably with intra-cell group route switching or intra-SpCell route switching.

[0071] In some embodiments, the ID of the fourth device 140 may be configured via an RRC reconfiguration message. For example, the ID may be indicated by ReconfigurationWithSync in an RRC reconfiguration message that includes information regarding path switching. In some embodiments, the ID of the fourth device 140 may be indicated by the third device 130. As another example, the ID of the fourth device 140 may be indicated by the third device 130 via a discovery message, PC5-RRC signaling, or PC5-S signaling. In some embodiments, the ID of the second device 120 may be indicated by the second device 120. For example, the ID of the second device 120 may be indicated during a synchronization procedure (e.g., a DL synchronization procedure) to the second device 120 or via an RRC message.

[0072] The determination of the configuration of the first device 110 for path switching may include at least one of starting a timer, DL synchronization, setting a MAC entity, or setting a sidelink MAC entity. It should be understood that any other suitable procedure may also be included. This is described in detail below. 1. Start the timer

[0073] In some embodiments, the first device 110 may start 210 a timer configured for the path switch. For example, the first device 110 may start the timer based on the timer setting included in the information regarding the path switch. The timer may be a timer other than T304.

[0074] In some embodiments, two timers may be configured: a timer (for convenience, also referred to herein as a first timer) for intra-gNB path switching (also referred to herein as intra-cell group or intra-SpCell path switching), and another timer (for convenience, also referred to herein as a second timer) for inter-gNB path switching (also referred to herein as inter-cell group or inter-SpCell path switching). In these embodiments, if the ID of the fourth device 140 is the ID of the second device 120, i.e., the target SpCell has not changed, the first device 110 may determine that the path switching is an intra-gNB path switching. In this case, the first device 110 may start the first timer configured for intra-gNB path switching. If the ID of the fourth device 140 is not the ID of the second device 120, i.e., the target SpCell has changed, the first device 110 may determine that the path switching is an inter-gNB path switching. In this case, the first device 110 may start a second timer configured for inter-gNB path switching. Thus, separate timers are configured for inter-gNB and intra-gNB path switching. It should be understood that the first timer and the second timer may be configured to have the same value or different values.

[0075] In some embodiments, the first timer may be configured to have a set of first values ​​for intra-gNB path switching, and the second timer may be configured to have a set of second values ​​for inter-gNB path switching. In these embodiments, an index may be configured to indicate the set of first values ​​or the set of second values. For example, an example of timer value configuration is shown in Table 1. In some embodiments, when the ID of the fourth device 140 is the ID of the second device 120, i.e., when it is intra-gNB path switching, the first device 110 may determine a first value (e.g., 15 ms) from the set of first values ​​based on the configured index (e.g., index=3) and start the first timer with the first value. If the ID of the fourth device 140 is not the ID of the second device 120, i.e., if it is inter-gNB path switching, the first device 110 may determine a second value (e.g., 25 ms) from a set of configured second values ​​based on the configured index (e.g., index=3), and start a second timer with the second value. TIFF2024546910000002.tif42168

[0076] In some embodiments, a timer value and an offset value may be set. In these embodiments, if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may determine a first value of the first timer based on the set timer value and start the first timer with the first value. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may determine a second value of the second timer based on the set timer value and the set offset value and start the second timer with the second value.

[0077] In some embodiments, a single timer may be configured for the first device 110. In these embodiments, the single timer may be configured to have a first value and a second value different from the first value. The first value may be used for intra-gNB path switching, and the second value may be used for inter-gNB path switching. For example, if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may start the single timer with the first value. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may start the single timer with the second value.

[0078] Thus, a timer is introduced for route switching to the relay UE. 2. DL sync

[0079] 2, the first device 110 may determine 220 whether the ID of the fourth device 140 is the ID of the second device 120. In some embodiments, the first device 110 may determine the ID of the fourth device 140 from information regarding the path change included in the RRC reconfiguration message. In some embodiments, the first device 110 may determine the ID of the fourth device 140 from a PC5 communication with the third device 130. The present disclosure is not limited to this aspect. This determination 220 may be performed in a similar manner as described above, and other details are omitted for brevity.

[0080] If the identity of the fourth device 140 is not the identity of the second device 120, the first device 110 may perform DL synchronization (221). That is, if the RRC reconfiguration message includes information regarding a path switch, and if the identity of the fourth device 140 is not the identity of the second device 120, the first device 110 may perform the DL synchronization. In some alternative embodiments, if the RRC reconfiguration message includes information regarding a path switch, and the information regarding the path switch indicates that the path switch is an inter-gNB path switch, the first device 110 may perform DL synchronization.

[0081] In some embodiments, the first device 110 may initiate synchronization to the DL of the fourth device 140. In some embodiments, the first device 110 may apply a defined broadcast control channel (BCCH) setting for the fourth device 140. In some embodiments, the first device 110 may obtain a master information block (MIB) of the fourth device 140.

[0082] In some embodiments, if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may omit reading the MIB of the fourth device 140. In some alternative embodiments, if the RRC reconfiguration message includes information regarding the path switch, and the information regarding the path switch indicates that the path switch is an intra-gNB path switch, the first device 110 may omit reading the MIB of the fourth device 140.

[0083] In some alternative embodiments, if the RRC reconfiguration message includes information regarding a path switch, the first device 110 may determine whether the necessary timing information is available. If the necessary timing information is available, the first device 110 may omit reading the MIB of the fourth device 140.

[0084] In some alternative embodiments, if the RRC reconfiguration message includes information regarding path switching, the first device 110 may determine whether timing information is not required for random access. If timing information is not required, the first device 110 may omit reading the MIB of the fourth device 140.

[0085] In some alternative embodiments, if the RRC reconfiguration message includes information regarding path switching, the first device 110 may determine whether the required MIB or some information elements (IEs) of the MIB for the fourth device 140 are obtained. If the required MIB or some IEs of the MIB are obtained, the first device 110 may omit reading the MIB of the fourth device 140.

[0086] In some alternative embodiments, if the RRC reconfiguration message includes information regarding path switching, the first device 110 may determine whether the third device 130 is configured as a relay UE for the first device 110. If the third device 130 is configured, the first device 110 may omit reading the MIB of the fourth device 140.

[0087] Thus, DL synchronization may be performed for route switching to the relay UE. 3. Setting up the MAC entity

[0088] 2, if the identity of the fourth device 140 is not the identity of the second device 120, the first device 110 may reset (230) a MAC entity of the cell group associated with the fourth device 140. That is, if the 201 RRC reconfiguration message indicates information about a path switch and the identity of the fourth device 140 is not the identity of the second device 120, reset the MAC entity of the cell group associated with the fourth device 140. In some alternative embodiments, if the RRC reconfiguration message includes information about a path switch and the information about the path switch indicates that the path switch is an inter-gNB path switch, the first device 110 may reset the MAC entity of the cell group associated with the fourth device 140.

[0089] In some embodiments, the first device 110 may apply the value of newUE-Identity as the Cell Radio Network Temporary Identifier (C-RNTI) for this cell group. In some embodiments, the first device 110 may consider the SCells (if configured) of this cell group that are not included in the SCellToAddModList in this RRC reconfiguration message to be in a deactivated state. In some embodiments, the first device 110 may configure the lower layers according to the received spCellConfigCommon. In some embodiments, the first device 110 may configure the lower layers according to any additional fields (if included in the received reconfigurationWithSync) not covered above.

[0090] If the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may reuse the MAC entity of the cell group associated with the fourth device 140 (231). That is, if the RRC reconfiguration message includes information regarding the path switch and if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may reuse the MAC entity of the cell group associated with the fourth device 140. In some alternative embodiments, if the RRC reconfiguration message includes information regarding the path switch and the information regarding the path switch indicates that the path switch is an intra-gNB path switch, the first device 110 may reuse the MAC entity of the cell group associated with the fourth device 140.

[0091] In some embodiments, the first device 110 may reuse the C-RNTI for this cell group. In some embodiments, the first device 110 may consider the SCells of this cell group to be in an activated state. In some embodiments, the first device 110 may consider the SCells of this cell group that are not included in the SCellToAddModList in this RRC reconfiguration message (if configured) to be in a deactivated state.

[0092] Thus, the MAC entity may be configured for routing to the relay UE. 4. Configuring the Sidelink MAC Entity

[0093] With reference to FIG. 2 , the first device 110 may determine (240) whether the path switch is an indirect-indirect path switch from a source device (e.g., another third device 131) to the third device 130. If the path switch is an indirect-indirect path switch, the first device 110 may determine (241) whether the ID of the third device 130 is the ID of the source device. If the ID of the third device 130 is not the ID of the source device, the first device 110 may reset (242) a sidelink specific MAC entity of the first device 110. In some alternative embodiments, if the path switch is an indirect-indirect path switch, the first device 110 may reset a sidelink specific MAC entity of the first device 110. For example, the first device 110 may reset a sidelink specific MAC associated with the source device before the first device 110 establishes a PC5 connection (i.e., a sidelink connection) with the third device 130. As another example, the first device 110 may reset a sidelink specific MAC associated with the source device after the first device establishes a PC5 connection with the third device 130.

[0094] Thus, the sidelink MAC entity may be configured for path switching to the relay UE. Up to this point, the configuration of the first device 110 for path switching has been determined, i.e. the first device 110 has been reconfigured. 5. Stopping the timer

[0095] 2, after the reconfiguration of the first device 110 is completed, the first device 110 may send an RRC reconfiguration complete message to the third device 130 by the sidelink adaptation layer or RLC layer of the first device 110 (204). That is, if the RRC reconfiguration message includes information regarding path switching, the upper layer (i.e., RRC layer) of the first device 110 may form an RRC reconfiguration complete message and indicate the lower layer (i.e., PDCP layer / sublayer) of the first device 110 to send it to the third device 130 via the PC5 connection.

[0096] The third device 130 may forward the RRC reconfiguration complete message to the fourth device 140 (205). The fourth device 140 may send an acknowledgment to the receipt of the RRC reconfiguration complete message to the third device 130 (206). In some embodiments, this acknowledgment may be a positive acknowledgment indicating successful receipt of the RRC reconfiguration complete message. In some embodiments, this acknowledgment may be a negative acknowledgment indicating unsuccessful receipt of the RRC reconfiguration complete message.

[0097] 2, the first device 110 may stop the timer (207). In some embodiments, the first device 110 may determine whether the RRC reconfiguration complete message was successfully transmitted (250). If the RRC reconfiguration complete message was successfully transmitted, the first device 110 may stop the timer. For example, if a lower layer (i.e., PHY layer) acknowledgment for transmitting the RRC reconfiguration complete message is received from the target relay (e.g., the third device 130), the first device 110 may stop the timer.

[0098] In some embodiments, the first device 110 may determine (260) whether the establishment of the PC5 unicast link (i.e., a sidelink connection) with the third device 130 was successful. If the establishment of the PC5 unicast link with the third device 130 was successful, the first device 110 may stop the timer.

[0099] In some embodiments, the third device 130 may send (270) an RRC reconfiguration complete sidelink message to the first device 110. In response to receiving the RRC reconfiguration complete sidelink message, the first device 110 may stop a timer.

[0100] In some embodiments, the third device 130 may send an indication (also referred to herein as a fourth indication for convenience) to the first device 110 regarding the RRC reconfiguration complete message (280). In response to receiving the fourth indication, the first device 110 may stop the timer. In some embodiments, the fourth indication may indicate that the RRC reconfiguration complete message has already been forwarded to the fourth device 140. In some embodiments, the fourth indication may indicate that the forwarding of the RRC reconfiguration complete message has already been acknowledged by the fourth device 140. In some embodiments, the fourth indication may indicate that the forwarding of the RRC reconfiguration complete message has not yet been acknowledged by the fourth device 140.

[0101] Up to this point, the route switch to the relay UE can be performed. Thus, the procedure for the route switch to the relay UE can be realized with minimal modification to the specification. Example of the method

[0102] Therefore, the embodiments of the present disclosure provide communication methods implemented in a terminal device and a network device, which are described below with reference to Figures 3 to 5.

[0103] 3 illustrates an example communication method 300 implemented in a first device as a remote UE, according to some embodiments of the present disclosure. For example, the method 300 may be performed in the first device 110 as shown in FIG. For purposes of explanation, the method 300 will be described below with reference to FIG. 1. It should be understood that the method 300 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0104] At block 310 , the first device 110 receives an RRC reconfiguration message from the second device 120 .

[0105] In block 320, the first device 110 determines whether the RRC reconfiguration message includes information regarding a route switch to the third device 130. The first device 110 communicates with a fourth device 140 serving the third device 130 via the third device 130, and communicates with the third device 130 via a sidelink interface.

[0106] In some embodiments, this information may include at least one of the following: an identity of the third device 130, an identity of the fourth device 140, a setting of a timer for the path switch, a first indication indicating a direct-indirect path switch or an indirect-indirect path switch, a second indication indicating a direct-indirect path switch, or a third indication indicating an indirect-indirect path switch.

[0107] If the RRC reconfiguration message includes this information, the process 300 proceeds to block 330. In block 330, the first device 110 determines the configuration of the first device 110 for the path switch based on the type of path switch. In some embodiments, the first device 110 may determine the configuration of the first device 110 for the path switch based on at least the ID of the fourth device 140 and the ID of the second device 120. Thus, the type of path switch may be implicitly determined. In some alternative embodiments, the first device 110 may determine the configuration of the first device 110 for the path switch based on an explicit indication of the type of path switch (e.g., intra-gNB path switch or inter-gNB path switch). Thus, the type of path switch may be explicitly determined.

[0108] In some embodiments, the first device 110 may start a timer configured for path switching. In some embodiments, the timer may include a first timer and a second timer. In these embodiments, the first device 110 may determine whether the ID of the fourth device 140 is the ID of the second device 120. If the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may start the first timer. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may start the second timer.

[0109] In some embodiments, the first timer may be configured to have a set of first values ​​and the second timer may be configured to have a set of second values. In these embodiments, an index may be set to indicate the set of first values ​​or the set of second values. In some embodiments, if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may determine a first value of the first timer from the set of first values ​​based on the set index and start the first timer with the first value. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may determine a second value of the second timer from the set of second values ​​based on the set index and start the second timer with the second value.

[0110] In some embodiments, a timer value and an offset value may be set. In these embodiments, if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may determine a first value of the first timer based on the set timer value and start the first timer with the first value. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may determine a second value of the second timer based on the set timer value and the set offset value.

[0111] In some embodiments where a single timer is set, the timer may be set to have a first value and a second value that is different from the first value. In these embodiments, if the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may start the timer with the first value. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may start the timer with the second value.

[0112] In some embodiments, the first device 110 may determine whether the ID of the fourth device 140 is the ID of the second device 120. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may perform operations including at least one of initiating synchronization with the DL of the fourth device 140, applying a BCCH setting defined for the fourth device 140, or obtaining a MIB of the fourth device 140.

[0113] In some embodiments, the first device 110 may determine whether the ID of the fourth device 140 is the ID of the second device 120. If the ID of the fourth device 140 is not the ID of the second device 120, the first device 110 may reset a MAC entity of the cell group associated with the fourth device 140. If the ID of the fourth device 140 is the ID of the second device 120, the first device 110 may reuse a MAC entity of the cell group associated with the fourth device 140.

[0114] In some embodiments, the ID of the fourth device 140 may include at least one of an ID of a cell group provided by the fourth device 140 or an ID of an SpCell provided by the fourth device 140. In some embodiments, the ID of the second device 120 may include at least one of an ID of a cell group provided by the second device 120 or an ID of an SpCell provided by the second device 120.

[0115] In some embodiments, the first device 110 may determine whether the path switch is an indirect-indirect path switch from the source device to the third device 130. If the path switch is an indirect-indirect path switch, the first device 110 may determine whether the identity of the third device 130 is the identity of the source device. If the identity of the third device is not the identity of the source device, the first device 110 may reset a sidelink specific MAC entity of the first device 110.

[0116] In some embodiments, the first device 110 may send an RRC reconfiguration complete message to the third device 130 via a sidelink adaptation layer or an RLC layer of the first device 110.

[0117] In some embodiments, the first device 110 may stop the timer in response to at least one of: successful transmission of the RRC reconfiguration complete message, successful establishment of a PC5 unicast link (i.e., sidelink connection) with the third device 130, receiving an RRC reconfiguration complete sidelink message from the third device 130, or receiving a fourth indication regarding the RRC reconfiguration complete message from the third device 130. In some embodiments, the fourth indication may indicate one of: that the RRC reconfiguration complete message has already been forwarded to the fourth device 140, that the forwarding of the RRC reconfiguration complete message has already been acknowledged by the fourth device 140, or that the forwarding of the RRC reconfiguration complete message has not yet been acknowledged by the fourth device 140.

[0118] The method of FIG. 3 can provide a procedure for route switching to a relay UE.

[0119] 4 illustrates an example communication method 400 implemented in a second device as a network device serving a remote UE, according to some embodiments of the present disclosure. For example, the method 400 may be performed in the second device 120 as shown in FIG. 1. For purposes of explanation, the method 400 will be described below with reference to FIG. 1. It should be understood that the method 400 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0120] In block 410, the second device 120 transmits an RRC reconfiguration message to the first device 110, the RRC reconfiguration message including information regarding the path switch to the third device 130. The first device 110 communicates with a fourth device 140 serving the third device 130 via the third device 130, and communicates with the third device 130 via a sidelink interface. For example, the second device 120 may cause the information regarding the path switch to be included in a ReconfigurationWithSnyc of the RRC reconfiguration message.

[0121] In some embodiments, this information may include at least one of the following: an identity of the third device 130, an identity of the fourth device 140, a setting of a timer for the path switch, a first indication indicating a direct-indirect path switch or an indirect-indirect path switch, a second indication indicating a direct-indirect path switch, or a third indication indicating an indirect-indirect path switch.

[0122] The method of FIG. 4 makes it possible to trigger a procedure for route switching to a relay UE.

[0123] 5 illustrates an example communication method 500 implemented in a third device as a relay UE, according to some embodiments of the present disclosure. For example, the method 500 may be performed in the third device 130 as shown in FIG. 1. For purposes of explanation, the method 500 will be described below with reference to FIG. 1. It should be understood that the method 500 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0124] At block 510 , the third device 130 receives an RRC reconfiguration complete message from the first device 110 .

[0125] In block 520, the third device 130 forwards the RRC reconfiguration complete message to the fourth device 140. The first device 110 communicates with the fourth device 140 serving the third device 130 via the third device 130, and communicates with the third device 130 via the sidelink interface.

[0126] At block 530, the third device 130 sends to the first device 110 a fourth indication regarding the RRC reconfiguration complete message.

[0127] In some embodiments, the fourth indication may indicate one of: that the RRC reconfiguration complete message has already been forwarded to the fourth device 140; that the forwarding of the RRC reconfiguration complete message has already been confirmed by the fourth device 140; or that the forwarding of the RRC reconfiguration complete message has not yet been confirmed by the fourth device 140.

[0128] The method of FIG. 5 can provide a procedure for route switching to a relay UE. Examples of equipment and devices

[0129] 6 is a schematic block diagram of an apparatus 600 suitable for implementing embodiments of the present disclosure. The apparatus 600 may be regarded as another exemplary implementation of the first apparatus 110 or the second apparatus 120 or the third apparatus 130 as shown in FIG. 1. Thus, the apparatus 600 can be implemented in or as at least a part of the first apparatus 110 or the second apparatus 120 or the third apparatus 130.

[0130] As shown, the apparatus 600 comprises a processor 610, a memory 620 coupled to the processor 610, a suitable transmitter (TX) and receiver (RX) 640 coupled to the processor 610, and a communication interface coupled to the TX / RX 640. The memory 610 stores at least a portion of a program 630. The TX / RX 640 is used for bidirectional communication. The TX / RX 640 has at least one antenna to facilitate communication, although the access nodes referred to herein may in practice have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 / Xn interface for bidirectional communication between eNBs / gNBs, an S1 / NG interface for communication between a Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and an eNB / gNB, an Un interface for communication between an eNB / gNB and a relay node (RN), or a Uu interface for communication between an eNB / gNB and a terminal device.

[0131] The program 630 is assumed to include program instructions that, when executed by the associated processor 610, enable the device 600 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 1-5. The embodiments of the present disclosure may be implemented by computer software executable by the processor 610 of the device 600, or by hardware, or by a combination of software and hardware. The processor 610 may be configured to implement various embodiments of the present disclosure. Furthermore, the combination of the processor 610 and the memory 620 may form a processing means 650 suitable for implementing various embodiments of the present disclosure.

[0132] The memory 620 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as, by way of non-limiting example, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Although only one memory 620 is shown in the device 600, there may be several physically different memory modules in the device 600. The processor 610 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP) and a processor based on a multi-core processor architecture. The device 600 may have multiple processors, for example application specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0133] In some embodiments, a first device comprises a circuit configured to receive an RRC reconfiguration message from a second device serving the first device, determine whether the RRC reconfiguration message includes information regarding a path switch to a third device, and determine a configuration of the first device for the path switch according to a determination that the RRC reconfiguration message includes the information. The first device communicates with a fourth device serving the third device via the third device and communicates with the third device via a sidelink interface.

[0134] In some embodiments, this information includes at least one of an identity of the third device, an identity of the fourth device, a timer setting for the path switch, a first indication indicating a direct-indirect path switch or an indirect-indirect path switch, a second indication indicating the direct-indirect path switch, or a third indication indicating the indirect-indirect path switch.

[0135] In some embodiments, the circuitry may be configured to determine the configuration by starting a timer configured for the path switching.

[0136] In some embodiments, the timer includes a first timer and a second timer. In these embodiments, the circuitry may be configured to start the timers by determining whether the identity of the fourth device is the identity of the second device, starting the first timer in accordance with a determination that the identity of the fourth device is the identity of the second device, and starting the second timer in accordance with a determination that the identity of the fourth device is not the identity of the second device.

[0137] In some embodiments, the circuitry may be configured to start the first timer by determining a first value for the first timer from a configured set of first values ​​based on a configured index, and to start the second timer by determining a second value for the second timer from a configured set of second values ​​based on the configured index.

[0138] In some embodiments, the circuitry may be configured to start a first timer by determining a first value for the first timer based on a set timer value, and to start a second timer by determining a second value for the second timer based on the set timer value and a set offset value.

[0139] In some embodiments, the timer is configured to have a first value and a second value different from the first value. In these embodiments, the circuitry may be configured to start the timer by determining whether the identity of the fourth device is the identity of the second device, starting the timer with the first value pursuant to a determination that the identity of the fourth device is the identity of the second device, and starting the timer with the second value pursuant to a determination that the identity of the fourth device is not the identity of the second device.

[0140] In some embodiments, the circuitry may be configured to determine the configuration by determining whether an identity of the fourth device is an identity of the second device, and, following a determination that the identity of the fourth device is not the identity of the second device, performing operations including at least one of initiating synchronization with a DL of the fourth device, applying a defined BCCH configuration for the fourth device, or obtaining a MIB of the fourth device.

[0141] In some embodiments, the circuitry may be configured to determine the configuration by determining whether an identity of the fourth device is an identity of the second device, resetting a MAC entity of a cell group associated with the fourth device in accordance with a determination that the identity of the fourth device is not the identity of the second device, and reusing the MAC entity of the cell group associated with the fourth device in accordance with a determination that the identity of the fourth device is the identity of the second device.

[0142] In some embodiments, the identity of the fourth device includes at least one of an identity of a cell group provided by the fourth device or an identity of a special cell provided by the fourth device, and the identity of the second device includes at least one of an identity of a cell group provided by the second device or an identity of a special cell provided by the second device.

[0143] In some embodiments, the circuitry may be configured to determine the configuration by determining whether the path switch is an indirect-indirect path switch from a source device to the third device, determining whether an identity of the third device is an identity of the source device in accordance with a determination that the path switch is the indirect-indirect path switch, and resetting a sidelink specific MAC entity of the first device in accordance with a determination that the identity of the third device is not the identity of the source device.

[0144] In some embodiments, the circuitry may be further configured to send, by a sidelink adaptation layer or a radio link control layer of the first device, an RRC reconfiguration complete message to the third device.

[0145] In some embodiments, the circuitry may be further configured to stop the timer in response to at least one of: successful transmission of an RRC reconfiguration complete message, successful establishment of a PC5 unicast link with the third device, receiving an RRC reconfiguration complete sidelink message from the third device, or receiving a fourth indication from the third device regarding the RRC reconfiguration complete message.

[0146] In some embodiments, the fourth indication indicates one of: that the RRC reconfiguration complete message has already been forwarded to the fourth device; that the forwarding of the RRC reconfiguration complete message has already been confirmed by the fourth device; or that the forwarding of the RRC reconfiguration complete message has not yet been confirmed by the fourth device.

[0147] In some embodiments, the second device comprises circuitry configured to transmit an RRC reconfiguration message to a first device served by the second device, the RRC reconfiguration message including information regarding a path switch to a third device, the first device communicating with a fourth device serving the third device via the third device, and communicating with the third device via a sidelink interface.

[0148] In some embodiments, the information includes at least one of an identity of the third device, an identity of the fourth device, a timer setting for the path switch, a first indication indicating a direct-indirect path switch or an indirect-indirect path switch, a second indication indicating the direct-indirect path switch, or a third indication indicating the indirect-indirect path switch.

[0149] In some embodiments, a third device comprises circuitry configured to receive an RRC reconfiguration complete message from a first device, forward the RRC reconfiguration complete message to a fourth device, and send a fourth indication to the first device regarding the RRC reconfiguration complete message. The first device communicates with the fourth device via the third device and communicates with the third device via a sidelink interface.

[0150] In some embodiments, the fourth indication indicates one of: that the RRC reconfiguration complete message has already been forwarded to the fourth device; that the forwarding of the RRC reconfiguration complete message has already been confirmed by the fourth device; or that the forwarding of the RRC reconfiguration complete message has not yet been confirmed by the fourth device.

[0151] In some embodiments, the first device and the third device are terminal devices, and the second device and the fourth device are network devices.

[0152] The term "circuitry" as used herein may refer to a hardware circuit and / or a combination of a hardware circuit and software. For example, a circuit may be a combination of analog and / or digital hardware circuitry and software / firmware. As yet another example, a circuit may be any portion of a hardware processor having software, including a digital signal processor, software, and one or more memories, that cooperate to cause a device, such as a terminal device or a network device, to perform various functions. In yet another example, a circuit may be a hardware circuit and / or a processor, such as a microprocessor or a portion thereof, that requires software / firmware for operation, but the software may not be present if not required for operation. As used herein, the term "circuitry" also includes an implementation of only a hardware circuit or one or more processors, or a portion of a hardware circuit or one or more processors and its (or their) associated software and / or firmware.

[0153] Overall, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure have been illustrated and described using block diagrams, flow charts, or some other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting examples, in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or any combination thereof.

[0154] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, that execute in a device on a target real or virtual processor to perform a process or method as described above with reference to Figures 1-5. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as appropriate. The machine-executable instructions of the program modules may be executed in local or distributed devices. In a distributed device, the program modules may be located in both local and remote storage media.

[0155] Program codes for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, a special purpose computer, or other programmable data processing device, and when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0156] The above program code may be implemented on a machine-readable medium, which may be any tangible medium that can contain or store a program used by or associated with an instruction execution system, device, or apparatus. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the aforementioned media. More specific examples of the machine-readable storage medium may include an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the aforementioned.

[0157] It should be noted that although operations have been described in a particular order, it should not be understood that such operations need to be performed in the particular order shown, or in any sequential order, or that all of the operations described must be performed in order to achieve desired results. In some cases, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to certain embodiments. Some features described in the context of individual embodiments may be realized in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately in multiple embodiments or in any suitable subcombination.

[0158] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure, as defined in the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A means for receiving a radio resource control (RRC) reconfiguration message indicating configuration information for path switching from a network device, the configuration information including an identity of a second terminal device for the path switching and a timer value of a timer for the path switching; means for determining the second terminal device indicated in the configuration information as a target relay user equipment (UE); A first terminal device comprising:

2. means for starting the timer with the timer value indicated in the configuration information; means for establishing a PC5 unicast link with the target relay UE; The first terminal device of claim 1 , further comprising:

3. means for stopping the timer if an RRC reconfiguration complete message is successfully transmitted; The first terminal device of claim 1 , further comprising:

4. The path switching corresponds to a direct-indirect path switching or an indirect-indirect path switching. A first terminal device according to claim 1 .

5. means for applying the value of newUE-Identity as a cell-radio network temporary identifier (C-RNTI); The first terminal device of claim 1 , further comprising:

6. A means for transmitting a radio resource control (RRC) reconfiguration message indicating configuration information for path switching to a first terminal device, the configuration information including an identity of a second terminal device for the path switching and a timer value of a timer for the path switching; The second terminal device indicated in the configuration information is determined by the first terminal device as a target relay user equipment (UE). Network device.

7. the timer value indicated in the configuration information is used by the first terminal device to start the timer; The target relay UE is used by the first terminal device to establish a PC5 unicast link. The network device according to claim 6.

8. The timer is stopped by the first terminal device when an RRC reconfiguration complete message is successfully sent to the network device. The network device according to claim 6.

9. The path switching corresponds to a direct-indirect path switching or an indirect-indirect path switching. The network device according to claim 6.

10. The value of newUE-Identity is applied by the first terminal device as a cell-radio network temporary identifier (C-RNTI); The network device according to claim 6.

11. 1. A method of communication performed by a first terminal device, comprising: receiving a radio resource control (RRC) reconfiguration message indicating configuration information for path switching from a network device, the configuration information including an identity of a second terminal device for the path switching and a timer value of a timer for the path switching; determining the second terminal device indicated in the configuration information as a target relay user equipment (UE); The method includes:

12. starting said timer with said timer value indicated in said configuration information; establishing a PC5 unicast link with the target relay UE; The method of claim 11 further comprising:

13. The method of claim 11, further comprising stopping the timer if an RRC reconfiguration complete message is successfully transmitted.

14. The method of claim 11, further comprising: applying the value of newUE-Identity as a cell-radio network temporary identifier (C-RNTI).

15. 1. A method of communication performed by a network device, comprising: Transmitting a radio resource control (RRC) reconfiguration message indicating configuration information for path switching to a first terminal device, the configuration information including an identity of a second terminal device for the path switching and a timer value of a timer for the path switching; The second terminal device indicated in the configuration information is determined by the first terminal device as a target relay user equipment (UE). method.

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