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WO2025043735A1 - Procédés, dispositifs et support de communication - Google Patents

Procédés, dispositifs et support de communication Download PDF

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Publication number
WO2025043735A1
WO2025043735A1 PCT/CN2023/116628 CN2023116628W WO2025043735A1 WO 2025043735 A1 WO2025043735 A1 WO 2025043735A1 CN 2023116628 W CN2023116628 W CN 2023116628W WO 2025043735 A1 WO2025043735 A1 WO 2025043735A1
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WO
WIPO (PCT)
Prior art keywords
terminal device
path
candidate
conditional
relay
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PCT/CN2023/116628
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English (en)
Inventor
You Li
Gang Wang
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NEC Corp
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NEC Corp
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Publication date
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Priority to PCT/CN2023/116628 priority Critical patent/WO2025043735A1/fr
Publication of WO2025043735A1 publication Critical patent/WO2025043735A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/36—Reselection control by user or terminal equipment
    • H04W36/362—Conditional handover

Definitions

  • Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices and computer storage media for conditional path switching.
  • a terminal device may communicate with the network device via a direct path or an indirect path. Specifically, in case of the direct path, the terminal device may communicate with the network device directly, while in case of the indirect path, the terminal device may communicate with the network device via at least one relay terminal device. Further, the location of the terminal device and the communication condition may change over time. In order to maintain a continuous communication with the network, the terminal device may be switched to a new path or connected to a new network device sometimes, i.e., performing a path switch.
  • embodiments of the present disclosure provide methods, devices and computer storage medium for path switching.
  • a remote terminal device comprising: a processor configured to cause the remote terminal device to: receive, from a first network device serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario; and in response to determining a path failure, determine, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • a first network device comprising: a processor configured to cause the first network device to: transmit, to a remote terminal device or a relay terminal device that is serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, wherein the first information being associated with a path failure scenario.
  • a relay terminal device comprising: a processor configured to cause the relay terminal device to: receive, from a first network device serving a remote terminal device, conditional path switch configuration information used for switching the remote terminal device from an indirect path to a further path, the remote terminal device communicating with the first network device via the first path associated with the relay terminal device, the conditional path switch configuration information indicating at least one switching condition corresponding to at least one candidate node comprising a candidate cell or a candidate relay terminal device, the conditional path switch configuration information being associated with a path failure scenario; and in response to detecting a radio link failure (RLF) with the first network device, transmit the conditional path switch configuration information to the remote terminal device.
  • RLF radio link failure
  • a remote terminal device comprising: a processor configured to cause the remote terminal device to: receive, from a first network device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates at least one candidate node to be switched to, and the at least one candidate node comprises a candidate cell or a candidate relay terminal device; in response to determining a path failure, initiate a reestablishment procedure to determine an available candidate node; and trigger, based on the conditional path switch configuration information, a switch to the second path associated with the available candidate node in accordance with a determination that the available candidate node is comprised in the at least one candidate node.
  • a first network device comprising: a processor configured to cause the first network device to: transmit, to a remote terminal device, conditional path switch configuration information and an indication, wherein, the conditional path switch configuration information is used for switching the remote terminal device from a first path to a second path, at least one of the first and second paths being indirect path; the indication indicates whether the conditional path switch configuration information is available in response to a path failure.
  • a first network device comprising: a processor configured to cause the first network device to: generate, a preparation request for a conditional path switch, the preparation request being associated with at least one of candidate relay device served by a second network device; and transmit the preparation request to the second network device.
  • a second network device comprising: a processor configured to cause the second network device to: receive, from a first network device, a preparation request for a conditional path switch for a remote terminal device, wherein the first network device is serving the remote terminal device and wherein the preparation request is associated with at least one of candidate relay device served by a second network device.
  • a communication method performed by a remote terminal device.
  • the method comprises: receiving, from a first network device serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario; and in response to determining a path failure, determining, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • a communication method performed by a first network device.
  • the method comprises: transmitting, to a remote terminal device or a relay terminal device that is serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, wherein the first information being associated with a path failure scenario.
  • a communication method performed by a relay terminal device.
  • the method comprises: receiving, from a first network device serving a remote terminal device, conditional path switch configuration information used for switching the remote terminal device from an indirect path to a further path, the remote terminal device communicating with the first network device via the first path associated with the relay terminal device, the conditional path switch configuration information indicating at least one switching condition corresponding to at least one candidate node comprising a candidate cell or a candidate relay terminal device, the conditional path switch configuration information being associated with a path failure scenario; and in response to detecting a radio link failure (RLF) with the first network device, transmitting the conditional path switch configuration information to the remote terminal device.
  • RLF radio link failure
  • a communication method performed by a remote terminal device.
  • the method comprises: receiving, from a first network device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates at least one candidate node to be switched to, and the at least one candidate node comprises a candidate cell or a candidate relay terminal device; in response to determining a path failure, initiating a reestablishment procedure to determine an available candidate node; and triggering, based on the conditional path switch configuration information, a switch to the second path associated with the available candidate node in accordance with a determination that the available candidate node is comprised in the at least one candidate node.
  • a communication method performed by a first network device.
  • the method comprises: transmitting, to a remote terminal device, conditional path switch configuration information and an indication, wherein, the conditional path switch configuration information is used for switching the remote terminal device from a first path to a second path, at least one of the first and second paths being indirect path; the indication indicates whether the conditional path switch configuration information is available in response to a path failure.
  • a communication method performed by a first network device.
  • the method comprises: generating, a preparation request for a conditional path switch, the preparation request being associated with at least one of candidate relay device served by a second network device; and transmitting the preparation request to the second network device.
  • a communication method performed by a second network device.
  • the method comprises: receiving, from a first network device, a preparation request for a conditional path switch for a remote terminal device, wherein the first network device is serving the remote terminal device and wherein the preparation request is associated with at least one of candidate relay device served by a second network device.
  • a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to the eighth, ninth, tenth, eleventh, twelfth, thirteenth, or fourteenth aspect.
  • FIG. 1A illustrates an example communication environment in which example embodiments of the present disclosure can be implemented
  • FIG. 1B illustrates an example communication environment in which example embodiments of the present disclosure can be implemented
  • FIGS. 2 to 8 illustrate signaling flows of communication in accordance with some embodiments of the present disclosure
  • FIG. 9 illustrates a flowchart of a method implemented at a remote terminal device according to some example embodiments of the present disclosure
  • FIG. 10 illustrates a flowchart of a method implemented at a first network device, according to some example embodiments of the present disclosure
  • FIG. 11 illustrates a flowchart of a method implemented at a relay terminal device according to some example embodiments of the present disclosure
  • FIG. 12 illustrates a flowchart of a method implemented at a remote terminal device according to some example embodiments of the present disclosure
  • FIG. 13 illustrates a flowchart of a method implemented at a first network device according to some example embodiments of the present disclosure
  • FIG. 14 illustrates a flowchart of a method implemented at a first network device according to some example embodiments of the present disclosure
  • FIG. 15 illustrates a flowchart of a method implemented at a second network device according to some example embodiments of the present disclosure.
  • FIG. 16 illustrates a simplified block diagram of an apparatus that is suitable for implementing example embodiments of the present disclosure.
  • terminal device refers to any device having wireless or wired communication capabilities.
  • the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, devices on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV)
  • UE user equipment
  • the ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporate one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM.
  • SIM Subscriber Identity Module
  • the term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.
  • network device refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate.
  • a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.
  • NodeB Node B
  • eNodeB or eNB evolved NodeB
  • gNB next generation NodeB
  • TRP transmission reception point
  • RRU remote radio unit
  • RH radio head
  • RRH remote radio head
  • IAB node a low power node such as a fe
  • the terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.
  • AI Artificial intelligence
  • Machine learning capability it generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.
  • the terminal or the network device may work on several frequency ranges, e.g., FR1 (e.g., 450 MHz to 6000 MHz) , FR2 (e.g., 24.25GHz to 52.6GHz) , frequency band larger than 100 GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum.
  • FR1 e.g., 450 MHz to 6000 MHz
  • FR2 e.g., 24.25GHz to 52.6GHz
  • THz Tera Hertz
  • the terminal device may have more than one connection with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario.
  • MR-DC Multi-Radio Dual Connectivity
  • the terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.
  • the embodiments of the present disclosure may be performed in test equipment, e.g., signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.
  • the terminal device may be connected with 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 one may be a secondary node.
  • the first network device and the second network device may use different radio access technologies (RATs) .
  • the first network device may be a first RAT device and the second network device may be a second RAT device.
  • the first RAT device is eNB and the second RAT device is gNB.
  • Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device.
  • first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device.
  • information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device.
  • Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.
  • the singular forms ‘a’ , ‘an’ and ‘the’ are intended to include the plural forms as well, unless the context clearly indicates otherwise.
  • the term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’
  • the term ‘based on’ is to be read as ‘at least in part based on. ’
  • the term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’
  • the term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’
  • the terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.
  • values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.
  • the term “resource, ” “transmission resource, ” “uplink resource, ” or “downlink resource” may refer to any resource for performing a communication, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like.
  • a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.
  • a terminal device may communicate with the network via a direct network connection or an indirect network connection. Further, in case of path switching, the communication path of the terminal device may be switched from a source network device to a target network device.
  • the source network device and the target network device are located in a same physical device (referred to as intra-gNB) . Alternatively, in some other embodiments, the source network device and the target network device are located in different physical devices (referred to as inter-gNB) .
  • a work item (WI) on sidelink relay has captured the procedures for intra-gNB indirect-to-direct (I2D) path switch.
  • the target relay UE may be in any RRC states (such as, e.g., IDLE/INACTIVE/CONNECTED) .
  • the WI on sidelink relay moves forward to the scenarios: indirect-to-indirect (I2I) of intra-gNB, and direct-to-indirect (D2I) of inter-gNB, indirect-to-indirect (I2D) of inter-gNB, indirect-to-indirect (I2I) of inter-gNB.
  • the channel condition may change rapidly due to the mobility of the remote UE and/or the relay UE.
  • the link quality of PC5 between the remote UE and relay UE may deteriorate rapidly, as well as the link quality of Uu for the relay UE.
  • the remote UE may not report the measurement results in time, or it may not receive the handover (HO) command in time. Therefore, methods to enhance robustness are needed, for example, CHO-like procedure may be introduced, which is called as CPS here.
  • the CHO is defined as a handover that is executed by the UE when one or more handover execution conditions are met.
  • the UE starts evaluating the execution condition (s) upon receiving the CHO configuration, and stops evaluating the execution condition (s) once a handover is executed. Further, the following principles may apply to CHO.
  • the CHO configuration contains the configuration of CHO candidate cell (s) generated by the candidate gNB (s) and execution condition (s) generated by the source gNB.
  • An execution condition may consist of one or two trigger condition (s) (i.e., CHO events A3/A5) . Only single RS type is supported and at most two different trigger quantities (e.g., reference signal receiving power (RSRP) and reference signal receiving quality (RSRQ) and signal to interference plus noise ratio (SINR) , etc. ) may be configured simultaneously for the evolution of CHO execution condition of a single candidate cell.
  • s i.e., CHO events A3/A5
  • RSRP reference signal receiving power
  • RSRQ reference signal receiving quality
  • SINR signal to interference plus noise ratio
  • the UE executes the HO procedure, regardless of any previously received CHO configuration.
  • UE While executing CHO, i.e., from the time when the UE starts synchronization with target cell, UE does not monitor source cell.
  • the IE ConditionalReconfiguration is used to add, modify and release the configuration of conditional reconfiguration. Further, if the indication attemptCondReconfig present, the UE shall perform conditional reconfiguration if selected cell is a target candidate cell and it is the first cell selection after a failure.
  • the IE CondReconfigToAddModList concerns a list of conditional reconfigurations to add or modify, with (for each entry) the condReconfigId and the associated condExecutionCond/condExecutionCondSCG and condRRCReconfig.
  • target/candidate cell and target/candidate relay UE may be indicated.
  • the target/candidate cell may be indicated by PhysCellId, which is included in RRCReconfiguration >>reconfigurationWithSync >> spCellConfigCommon
  • target/candidate relay UE may be indicated by targetRelayUE-Identity, which is included in RRCReconfiguration >> reconfigurationWithSync >> sl-PathSwitchConfig.
  • targetRelayUE-Identity indicates the L2 source ID of the target L2 U2N relay UE during path switch.
  • actions following cell selection while T311 is running may be:
  • the path switch may be supported.
  • D2I Downlink Control
  • CondEvent Y1 primary cell (PCell) becomes worse than absolute threshold1 and Conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute threshold2; configured with threshold1 and threshold2.
  • CondEvent Y2 conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than absolute threshold; configured with threshold.
  • CondEvent Y3 distance between (Remote) UE and referenceLocation1 of Pcell becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold distanceThreshFromReference2; configured with distanceThreshFromReference1, distanceThreshFromReference2.
  • CondEvent Z1 serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute threshold2; configured with threshold1 and threshold2.
  • CondEvent Z3 distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold distanceThreshFromReference2; Configured with distanceThreshFromReference1, distanceThreshFromReference2.
  • CondEvent X1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration candidate (NR cell) becomes better than another absolute threshold2; configured with threshold1 and threshold2.
  • Conditional reconfiguration candidate (NR cell) becomes better than absolute threshold; configured with threshold.
  • CondEvent X2 Serving L2 U2N relay UE becomes worse than absolute threshold.
  • a direct network connection/adirect path refers to one mode of network connection, where there is no relay terminal device/relay UE between a terminal device and the network de-vice; also referred to as a direct path sometime.
  • An indirect network connection/an indirect path refers to one mode of network connection, where there is a relay terminal device/relay UE between a terminal device and the network device; also referred to as a relaying path or indirect path sometimes.
  • a remote terminal device refers to a terminal device may communicate with a network device via either a direct path or an indirect path.
  • a first network device refers to a serving network device of the remote terminal device and/or the source relay terminal device before a CPS procedure.
  • a second network device refers to a serving network device of the remote terminal device and/or the target relay terminal device after a CPS procedure.
  • the first network device and the second network device may be a single network device, such as the intra-node/intra-gNB case.
  • ⁇ D2I path switching refers to switching from direct to indirect path, or switching to indirect path via a Relay UE.
  • ⁇ I2I path switching refers to switching from indirect to indirect path, or switching from an indirect path via a first relay UE to another indirect path via a second Relay UE.
  • ⁇ I2D path switching refers to switching from direct to indirect path, or switching from an indirect path via a relay UE to a cell, such as Pcell.
  • a candidate node/device may be referred to as a target node/device when it is selected. Further, if the candidate node/device is not selected, the candidate node/device may be called as the other (potential) target network device (s) .
  • wording of “trigger/perform a path switch based on a configuration” may refer to: 1) the configuration of the candidate node associated with the target path is comprised in the configuration; or 2) apply the configuration to trigger/perform the path switch.
  • radio failure In the present disclosure, the terms “radio failure” , “path failure” , “abnormal case” may be used changeably sometimes.
  • preparation cancel message may be used changeably sometimes.
  • SL-RSRP and SD-RSRP are used as examples of measurement results performed on different signals, it should not be considered as any limitations of the present disclosure.
  • the SL-RSRP and SD-RSRP may be replaced by any suitable channel quality parameters, such as, received signal strength indicator (RSSI) , signal to noise plus interference ratio (SNIR) and so on.
  • RSSI received signal strength indicator
  • SNIR signal to noise plus interference ratio
  • FIG. 1A shows an example communication environment 100A in which example embodiments of the present disclosure can be implemented.
  • the communication environment 100A comprises a plurality of terminal devices and network devices.
  • the communication environment 100 comprises a network device 120-1, and a network device 120-2.
  • the network devices 120-1 and 120-2 are collectively referred to as network device 120, or individually refers to as the first network device 120-1 and the second network device 120-2, respectively.
  • both inter-gNB network structure and intra-gNB network structure are supported in the communication environment 100.
  • the communication environment 100 further comprises a terminal device 110 and a terminal device 130.
  • the terminal device 110 may communicate with the network device 120 via the terminal devices 130.
  • the terminal devices 110, the terminal device 130 are individually refers to as the remote terminal device 110, the relay terminal device 130, respectively.
  • a path switching maybe associated with any of: indirect-to-direct (I2D) path switching for intra-gNB, indirect-to-indirect (I2I) path switching for intra-gNB, direct-to-indirect (D2I) path switching for intra-gNB, I2D for inter-gNB, I2I for inter-gNB.
  • I2D indirect-to-direct
  • I2I indirect-to-indirect
  • D2I direct-to-indirect
  • the CPS scenario also may comprise other candidate node, such as, a candidate relay terminal device, a candidate cell, a candidate network device.
  • the candidate relay terminal device may be served by any of the first/target/candidate network device, the source/second network device, or other candidate network device.
  • the communication network may include any suitable number of network devices and/or terminal devices adapted for implementing implementations of the present disclosure.
  • the communications in the communication environments 100 and 150 may conform to any suitable standards 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.
  • GSM Global System for Mobile Communications
  • LTE Long Term Evolution
  • LTE-Evolution LTE-Advanced
  • NR New Radio
  • WCDMA Wideband Code Division Multiple Access
  • CDMA Code Division Multiple Access
  • GERAN GSM EDGE Radio Access Network
  • MTC Machine Type Communication
  • Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.
  • FIG. 2 to FIG. 8 will be described with reference to FIGS. 1A and 1B.
  • some interactions are performed among the remote terminal device 110 and the network device 120. It is to be understood that the interactions may be implemented either in one single signaling/message or multiple signaling/messages, including system information, radio resource control (RRC) message, downlink control information (DCI) message, uplink control information (UCI) message, media access control (MAC) control element (CE) , sidelink relay adaptation protocol (SRAP) and so on.
  • RRC radio resource control
  • DCI downlink control information
  • UCI uplink control information
  • CE media access control
  • SRAP sidelink relay adaptation protocol
  • the remote terminal device may be configured with configuration (s) of CPS or conditional handover (CHO)
  • the relay terminal device 130 also may be configured with related configuration (s) of CPS.
  • the channel condition may change rapidly due to the mobility of the remote UE and/or relay UE.
  • the link quality of PC5 between the remote UE and relay UE may deteriorate rapidly, as well as the link quality of Uu for the relay UE.
  • the remote UE may not report the measurement results in time, or it may not receive the handover (HO) command in time.
  • CPS conditional path switching/switch
  • a reestablishment procedure may be initiated by sending of RRCReestablishmentRequest.
  • the reestablishment procedure may introduce interruption of data transmission.
  • the interruption of data transmission caused by the radio failure may be reduced by utilizing the CPS configuration.
  • FIG. 2 illustrates a signaling flow 200 of communication in accordance with some embodiments of the present disclosure.
  • the remote terminal device 110 receives 210 conditional path switch configuration information from the first network device 120-1, where the conditional path switch configuration information may be used for switching the remote terminal device 110 from a first path to a second path.
  • the conditional path switch configuration information indicates first information, where the first information indicates at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, and the first information is associated with a path failure scenario.
  • the remote terminal device 110 determines 250, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • the remote terminal device 110 may determine the path failure by detecting a PC5 failure by itself.
  • the remote terminal device 110 may determine the path failure in response to receiving 230 from a relay terminal device that is serving the remote terminal device 110, a notification message indicating at least one of the following:
  • the remote terminal device 110 in addition to the first information, also may receive second information from the first network device 120-1.
  • the second information may indicate at least one second switching condition corresponding to at least one second candidate node comprising a candidate cell or a candidate relay terminal device, the second information being associated with a normal path switch scenario.
  • Both the first information and the second information may be configured by the conditional path switch configuration information. Or they may be configured by separate conditional path switch configuration information or different RRC messages. Alternatively, or in addition, the first information and the second information may be the same information.
  • a normal path switch scenario means a scenario rather than the radio failure scenario, which means that the remote terminal device 110 performs measurements and determines whether a switch condition is met regardless of whether detecting a radio failure.
  • conditional path switch configuration information may be comprised in a hierarchical information structure.
  • a message (such as, an RRC message) may comprise at least one (conditional) path switch configuration (such as, CondTriggerConfig)
  • each path switch configuration may comprise one candidate node, corresponding configuration for path switch and at least one corresponding conditional trigger event (such as, CondEvent)
  • each conditional trigger event may correspond to a parameter set (such as, timeToTrigger, hysteresis, Threshold) .
  • the first and second information may be represented in multiple manners as discussed below.
  • the first/second switching condition may correspond to a (conditional) path switch configuration (such as, CondTriggerConfig) which is corresponding to a candidate cell/relay terminal device.
  • a (conditional) path switch configuration such as, CondTriggerConfig
  • Each path switch configuration may be configured with up to two conditional trigger event. If the conditional trigger event (s) is detected, a switch to the candidate cell/relay terminal device may be performed .
  • each path switch configuration may be configured with at least two conditional trigger events.
  • the first/second switching condition may correspond to a conditional trigger event (such as, CondEvent)
  • the conditional trigger event may be associated with a path switch configuration (corresponding to a candidate cell/relay terminal device) .
  • a switch to the candidate cell/relay terminal device may be performed.
  • the first/second switching condition may correspond to a parameter set (such as, a time to trigger, a triggering threshold for selecting the candidate node and so on) , and the parameter set is associated with a conditional trigger event.
  • the conditional trigger event may be detected based on the parameter set.
  • a switch to the candidate cell/relay terminal device may be performed.
  • the second information may correspond to a second (conditional) path switch configuration and the first information may correspond to a first (conditional) path switch configuration different from the second path switch configuration.
  • the same or different candidate nodes may be configured for the normal and radio failure scenarios.
  • the first path switch configuration may indicate a first candidate node without being configured with execution condition. That is, the remote terminal device 110 may switch to the first candidate node upon determining 240 a path failure or the radio failure without performing any measurements.
  • the first candidate node is specified for a path failure or the radio failure, which can be selected without performing any measurements.
  • the first path switch configuration may indicate a first candidate node being configured with the first switching condition being at least one of the following:
  • one second switching condition may correspond to a second path switch configuration and one first switching condition may correspond to a first path switch configuration different from the second path switch configuration.
  • the second information may correspond a second conditional trigger event associated with a path switch configuration (corresponding to a candidate node)
  • the first information may correspond a first conditional trigger event associated with the same path switch configuration (corresponding to the same candidate node.
  • the same candidate node (s) may be configured for the normal and radio failure scenarios, while the same or different conditional trigger event (s) may be configured for the normal and radio failure scenarios.
  • first requirements associated with the first conditional trigger event may be lower than second requirements associated with the second conditional trigger event.
  • the first conditional trigger event corresponds a first set of parameters (i.e., the first requirements, such as, a time duration to trigger, a triggering threshold for selecting the candidate node and so on)
  • the second conditional trigger event corresponds a second set of parameters (i.e., the second requirements, such as, a time duration to trigger, a triggering threshold for selecting the candidate node and so on)
  • the second requirements/second set of parameters may correspond to a shorter time to trigger, a lower triggering threshold for selecting the candidate node and so on.
  • one second switching condition may correspond a second conditional trigger event associated with a path switch configuration
  • one first switching condition may correspond a first conditional trigger event associated with the same path switch configuration/same candidate node.
  • the second information may correspond a second parameter set associated with a conditional trigger event
  • the first information may correspond a first parameter set associated with the same conditional trigger event
  • third requirements associated with the first parameter set may be lower than fourth requirements associated with the second parameter set.
  • the third requirements may correspond to a shorter time to trigger, a lower triggering threshold for selecting the candidate node and so on.
  • one second switching condition may correspond a second parameter set associated with a conditional trigger event
  • one first switching condition may correspond a first parameter set associated with the same conditional trigger event
  • the first parameter set may be represented as an offset set relative to the second parameter set and vice versa.
  • a correspondence between the first and second path switch configurations and the normal and path failure scenarios may be determined based on a default rule or determined based on an indication configured by the first network device 120-1.
  • a correspondence between the first and second conditional trigger events and the normal and path failure scenarios may be determined based on a default rule or determined based on an indication configured by the first network device 120-1.
  • a correspondence between the first and second parameter sets and the normal and path failure scenarios may be determined based on a default rule or determined based on an indication configured by the first network device 120-1.
  • whether the remote terminal device 110 is allowed to apply the first information is configurable. As illustrated in FIG. 2, the remote terminal device 110 may receive 220 an indication from the first network device 120-1, where the indication indicates whether the first information is available in response to the path failure. That is, the indication indicates whether the first information may be applied to the selected candidate node upon the path failure.
  • the remote terminal device 110 may transmit 250 a reestablishment message in response to at least one of the following: not receiving an indication indicating whether the first information is available in response to the path failure, or not receiving the first information.
  • the remote terminal device 110 may start measurements on the at least one first candidate node.
  • the remote terminal device 110 may determine whether a first switching condition of the at least one first switching condition is met based on measurement results of the at least one first candidate node, wherein at least part of the measurement results are obtained prior to determining the path failure. That is, the remote terminal device 110 may start measurements before determining the path failure. However, the remote terminal device 110 does not determine whether the first switching condition is met before determining the path failure. When determining the path failure, the remote terminal device 110 determine whether the current measurement results are sufficient enough to determine whether the first switching condition is met. If so, the remote terminal device 110 determines whether the first switching condition is met based on the current measurement results. Else, the remote terminal device 110 continues the measurement to obtain enough measurement results, and then determines whether the first switching condition is met.
  • the remote terminal device 110 may determine or select a first candidate node based on determinations about whether a first switching condition of the at least one first switching condition is met, wherein the determinations are obtained prior to determining the path failure.
  • the remote terminal device 110 may start measurements before determining the path failure, while the remote terminal device 110 determines whether the first switching condition is met based on the measurement results.
  • the remote terminal device 110 does not trigger a switch to the candidate node. Instead, upon detecting a path failure, the remote terminal device 110 may check whether the first switching condition is met. If so, the path switch to the candidate node may be triggered.
  • FIG. 3 illustrates a signaling flow 300 of communication in accordance with some embodiments of the present disclosure.
  • the remote terminal device 110 communicate with the first network device 120-1 via the first path associated with the relay terminal device 130.
  • the relay terminal device 130 receives 310 from a first network device 120-1 serving the remote terminal device 110, conditional path switch configuration information used for switching the remote terminal device 110 from an indirect path to a further path.
  • conditional path switch configuration information indicates at least one switching condition corresponding to at least one candidate node comprising a candidate cell or a candidate relay terminal device 130.
  • conditional path switch configuration information is associated with a path failure scenario. In other words, the conditional path switch configuration information will be applied upon the relay terminal device 130 determining a path failure.
  • conditional path switch configuration information may comprise the first information as discussed above. Merely for brevity, the same or similar contents are omitted here.
  • the relay terminal device 130 may transmit 330 the conditional path switch configuration information to the remote terminal device 110.
  • RLF radio link failure
  • the relay terminal device 130 may determine the path failure in response to at least one of the following:
  • the remoter terminal device 110 may apply the conditional path switch configuration information. Specifically, if the conditional path switch configuration information indicates a candidate node (s) (without switching condition (s) ) , the remoter terminal device 110 may switch to candidate node without any additionally measurements.
  • conditional path switch configuration information indicates a candidate node (s) with switching condition (s)
  • the remoter terminal device 110 may perform measurements and determines whether the switching condition (s) is met.
  • the path switch may be triggered by applying the conditional path switch configuration information.
  • FIG. 4 illustrates a signaling flow 400 of communication in accordance with some embodiments of the present disclosure.
  • the remote terminal device 110 receives 410 conditional path switch configuration information from a first network device 120-1.
  • the conditional path switch configuration information is used for switching the remote terminal device from a first path to a second path, and further at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates at least one candidate node to be switched to.
  • the remote terminal device 110 In response to determining 440 a path failure, the remote terminal device 110 initiates 450 a reestablishment procedure to determine/select an available candidate node. Then, if an available candidate node is selected or determined, in accordance with a determination that the available candidate node is comprised in the at least one candidate node, the remote terminal device 110 triggers 460 based on the conditional path switch configuration information, a switch to the second path associated with the available candidate node.
  • conditional path switch configuration information may comprise the following:
  • candidate nodes such as, candidate relays, including relay UE ID, PC5 RLC configurations, E2E radio bearers, adaptation layer configurations, and/or candidate cells, including radio bearers, Uu RLC configurations and so on
  • candidate relays including relay UE ID, PC5 RLC configurations, E2E radio bearers, adaptation layer configurations, and/or candidate cells, including radio bearers, Uu RLC configurations and so on
  • candidate cell is the serving cell of the remote UE;
  • execution condition including any PC5 and/or Uu measurements that have been agreed to trigger a switching from direct path to indirect path as well as switching from indirect path to direct path or from indirect path to indirect path.
  • the conditional path switch configuration information may indicate a corresponding condition (s) used for triggering a switch to the candidate node, and also comprise a set of parameters used for communicating with the candidate node (such as, for initial access or for connection establishment) .
  • trigger a switch to the second path means that using the set of parameters comprised in the conditional path switch configuration information to communicate with a network device (e.g., the first network device) via a new path (i.e., the second path) including the candidate node.
  • trigger a switch to the second path means that performing/applying/using the set of parameters comprised in the (stored) conditional path switch configuration corresponding to the available/selected candidate node (also referred to as perform conditional reconfiguration for the available/selected candidate node) and/or initiate a PC5 connection establishment with the candidate node.
  • the remote terminal device 110 may determine the path failure in response to at least one of the following:
  • the remote terminal device 110 may detect the path failure by detecting a PC5 or Uu failure by itself.
  • the remote terminal device 110 may detect the path failure in response to receiving 430 from a relay terminal device that is serving the remote terminal device 110, a notification message indicating at least one of the following:
  • the remote terminal device 110 may transmit, a reestablishment message to the available candidate node in accordance with a determination that the available candidate node is not comprised in the at least one candidate node.
  • whether the remote terminal device 110 is allowed to apply the conditional path switch configuration information is configurable. As illustrated in FIG. 4, the remote terminal device receives 420 an indication from the first network device 120-1, where the indication indicates whether the conditional path switch configuration information is available in response to the path failure. That is, the indication indicates whether the conditional path switch configuration information may be applied to the available candidate node selected in operation 450.
  • the remote terminal device 110 may trigger a switch to the second path if the indication is enabled or indicates the conditional path switch configuration information is available in response to the path failure. In other words, the remote terminal device 110 may perform conditional reconfiguration for the available/selected candidate node.
  • the remote terminal device 110 may trigger a switch to the second path if the available/selected candidate node is configured with conditional path switch configuration.
  • the available/selected candidate node is one of the candidate node configured in the conditional path switch configuration information.
  • the remote terminal device 110 may trigger a switch to the second path if : 1) the indication is enabled (such as the indication is present or set to ‘true’ ) and 2) the available candidate node is configured with conditional path switch configuration.
  • the remote terminal device 110 may trigger a switch to the second path if at least one of the following: 1) the indication is enabled; 2) the available candidate node is determined upon the path failure/radio link failure; 3) the available candidate node is configured with conditional path switch configuration; and 4) it is the first candidate node selection (such as node (re) selection or relay UE (re) selection) after the path failure (also referred to as the first selected candidate node (such as relay UE) after the path failure) .
  • the first candidate node selection such as node (re) selection or relay UE (re) selection
  • the path failure also referred to as the first selected candidate node (such as relay UE) after the path failure
  • the remote terminal device 110 may trigger a switch to the second path if the indication is enabled, the available candidate node is configured with conditional path switch configuration, it is the first candidate node selection after the path failure and the selection/determine of candidate node is triggered upon determining the path failure.
  • the available candidate node may be the first candidate node detected during the reestablishment procedure.
  • the source gNB and the target gNB may complete the preparation by exchanging a handover request and handover request acknowledge.
  • the target gNB may consider that the request concerns a conditional handover and may include the Conditional Handover Information Acknowledge IE in the HANDOVER REQUEST ACKNOWLEDGE message.
  • a handover request and handover preparation failure may be exchanged between the source gNB and the target gNB.
  • the target gNB may include the Requested Target Cell ID IE in the HANDOVER PREPARATION FAILURE message.
  • the target gNB reject the procedure using the HANDOVER PREPARATION FAILURE message.
  • a handover cancel procedure may be used to enable a source gNB to cancel an ongoing handover preparation or an already prepared handover.
  • the source gNB initiates the procedure by sending the HANDOVER CANCEL message to the target gNB.
  • the source gNB may indicate the reason for cancelling the handover by means of an appropriate cause value.
  • the target gNB may consider that the source gNB is cancelling only the handover associated to the candidate cells identified by the included NG-RAN CGI and associated to the same UE-associated signaling connection identified by the Source NG-RAN node UE XnAP ID IE and, if included, also by the Target NG-RAN node UE XnAP ID IE.
  • the handover cancel procedure also may be indicated by the target gNB.
  • a conditional handover cancel procedure may be used to enable a target gNB to cancel an already prepared conditional handover.
  • the target gNB initiates the procedure by sending the CONDITIONAL HANDOVER CANCEL message to the source NG-RAN node.
  • the target gNB may indicate the reason for cancelling the conditional handover by means of an appropriate cause value.
  • the source gNB may consider that the target gNB is about to remove any reference to, and release any resources previously reserved for candidate cells associated to the UE-associated signalling identified by the source NG-RAN node UE XnAP ID IE and the Target NG-RAN node UE XnAP ID IE. If the Candidate Cells To Be Cancelled List IE is included in CONDITIONAL HANDOVER CANCEL message, the source gNB may consider that only the resources reserved for the cells identified by the included NG-RAN CGI are about to be released.
  • FIG. 5 illustrates a signaling flow 500 of communication in accordance with some embodiments of the present disclosure.
  • the first network device 120-1 may generate, a preparation request for a conditional path switch, where the preparation request is associated with at least one of candidate relay device served by a second network device 120-2, and then the first network device 120-1 transmits 510 the preparation request to the second network device 120-2.
  • the preparation request may be a per UE request, which means that one preparation request is dedicated for a specific remote terminal device.
  • the first network device 120-1 may generate more than one preparation request, and each preparation request may correspond to a specific remote terminal device.
  • the at least one of candidate relay device is one of the following:
  • ⁇ a first set of candidate relay devices served by the second network device 120-2, i.e., per cell preparation request, or
  • ⁇ a second set of candidate relay devices served by a cell provided by the second network device 120-2, i.e., per gNB preparation request.
  • the first network device 120-1 may transmit the preparation request in response to an initiation of the conditional path switch, or an update of the conditional path switch.
  • the preparation request may indicate a type of the conditional path switch being one of the following:
  • the preparation request may be comprised in a handover preparation request.
  • the first network device 120-1 may receive 520 a (preparation) response to the preparation request from the second network device 120-2, where the preparation response may be associated with at least one of the following:
  • the response may be a request acknowledge or a preparation failure. In some embodiments, the response may be comprised in a preparation response. In some embodiments, the preparation response may be a handover request acknowledge or a preparation failure.
  • the preparation failure may indicate at least one candidate relay device with a preparation failure.
  • a cause value for the preparation failure of a candidate relay device of the at least one candidate relay device may be one of the following:
  • the candidate relay device being not available (such as, the relay terminal device is out of the coverage of the network device ) , or
  • either the first network device 120-1 or the second network device 120-2 may cancel the preparation for the candidate node (s) .
  • the first network device 120-1 may transmit 530 a first cancel message to the second network device 120-2, the first cancel message comprising at least one of the following:
  • ⁇ an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell
  • As the first cancel message may be transmitted prior to or after the response, and thus both on going and prepared candidate node (s) may be cancelled accordingly.
  • the first network device 120-1 may receive a second cancel message from the second network device 120-2, the second cancel message comprising:
  • ⁇ an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell
  • the first network device 120-1 may receive the second cancel message from the second network device 120-2 after receiving the handover request acknowledge. That is, the second network device 120-2 trasnmits the second cancel message after transmitting the handover request acknowledge, i.e., the second network device 120-2 may cancel the prepared candidate node (s) .
  • the number of candidate relay terminal device indicated by the first or second cancel message may be a multiple of a predefined number (such as, 32 or 8) .
  • FIG. 6A illustrates a signaling flow 600A of communication in accordance with some embodiments of the present disclosure.
  • Example of FIG. 6A is associated with I2D/I2I scenario.
  • the remote UE is configured with CPS configurations. Upon radio failure, the remote UE selects one candidate node which is,
  • the remote UE is configured with CPS configuration, including at least one of the following:
  • Candidate node at least one candidate cell and/or candidate relay UE, and
  • each candidate node such as, a cell or relay UE
  • the CPS configuration follows a legacy manner. That is, the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) (with up to 2 trigger conditions) .
  • the CPS configuration is represented as CPS configuration #1.
  • the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) , wherein each execution condition consists of at least two trigger conditions.
  • each execution condition consists of at least two trigger conditions.
  • one execution condition is sued for legacy evaluation/normal case and the other execution condition is used for the radio failure case.
  • such CPS configuration is represented as CPS configuration #2.
  • the two trigger conditions may have the same or different event conditions. If the two trigger conditions have the same event condition, the latter one (i.e., the execution condition for the radio failure) may have a looser requirement for selecting candidate node, for example, a shorter time to trigger, a lower triggering threshold for selecting the candidate node.
  • the first trigger condition is used for normal case
  • the second one is used for the radio failure case
  • the CPS configuration indicates at least one candidate node of the radio failure case.
  • a specific CPS configuration/CPS execution condition is configured for the radio failure case.
  • such CPS configuration is represented as CPS configuration #3.
  • the CPS configuration #3 is configured without corresponding execution conditions.
  • the CPS configuration #3 is configured with execute condition, which consists of radio failure case.
  • execute condition which consists of radio failure case.
  • new trigger condition s
  • the new trigger condition may be CondEvent #1: determining radio failure cases, such as,
  • the new trigger condition may be CondEvent #2: CondEvent #2: determining radio failure cases, such as
  • the CPS configuration #3 is configured execute condition, which consists of legacy execute condition for CHO/CPS.
  • the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) (with up to 2 trigger conditions) , where each trigger condition is configured with two sets of parameters.
  • CPS configuration #4 such CPS configuration is represented as CPS configuration #4.
  • the CPS configuration #4 indicates an offset/another hysteresis for triggering threshold and/or an offset for time to trigger, which will be used upon determining radio failure cases. Additionally, each of these offsets has a positive value.
  • the CPS configuration #4 indicates two sets of (triggering threshold (s) and/or timer to trigger) , i.e., the first set used for normal case; and the second set used upon determining radio failure cases.
  • triggering threshold (s) and/or timer to trigger i.e., the first set used for normal case; and the second set used upon determining radio failure cases.
  • parameters in the second set are of a looser requirement than those in the first set.
  • the CPS configuration #4 may indicates at least one of the following:
  • CondEvent Z1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute threshold2; (the first set) is configured with threshold1 and threshold2.
  • the second set is configured with at least threshold2-1, where threshold2-1 ⁇ threshold2.
  • CondEvent Z3 Distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold distanceThreshFromReference2; (the first set) is configured with distanceThreshFromReference1, distanceThreshFromReference2.
  • the second set is configured with at least distanceThreshFromReference2-1, where distanceThreshFromReference2-1 >distanceThreshFromReference2.
  • the CPS configuration #4 may indicates at least one of the following:
  • CondEvent X1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration candidate (NR cell) becomes better than another absolute threshold2; (the first set) is configured with threshold1 and threshold2.
  • the second set configured with at least threshold2-1, where threshold2-1 ⁇ threshold2.
  • CondEvent X3 Distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (NR cell) becomes shorter than configured threshold distanceThreshFromReference2; (the first set) is configured with distanceThreshFromReference1, distanceThreshFromReference2.
  • the second set configured with at least distanceThreshFromReference2-1, where distanceThreshFromReference2-1 >distanceThreshFromReference2.
  • Conditional reconfiguration candidate becomes better than absolute threshold; (the first set) is configured with threshold.
  • an offset/hysteresis As one example, an offset/hysteresis.
  • the second set configured with at least threshold1-1, where threshold1-1 ⁇ threshold.
  • the CPS configurations #2 to #4 define a specific CPS configuration/execution condition.
  • Table 1 illustrates general structures of the CPS configurations #2 to #4.
  • table 1 structures of the CPS configurations #2 to #4
  • the remote UE upon receiving the CPS configuration #1, the remote UE receives and stores the received CPS configuration. Further, upon receiving the CPS configuration, the remote UE may start evaluating the CPS execution conditions for the candidate node (s) .
  • the remote UE upon receiving the CPS configuration #1, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) based on the trigger condition of normal case. Additionally, the remote UE starts evaluating the CPS execution conditions based on the trigger condition of radio failure cases.
  • the remote UE starts the evaluation/measurement based on the specific trigger condition, but does not judge whether the condition is met. May perform judgement until the action 10 as illustrated in FIG. 6A.
  • the remote UE upon receiving the CPS configuration #3, the remote UE does not need to evaluate the CPS execution conditions for candidate node of radio failure cases.
  • the remote UE upon receiving the CPS configuration #3, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) of normal CPS configurations. Additionally, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) of the specific CPS configurations.
  • the remote UE starts the evaluation/measurement based on the specific CPS configuration (i.e., CPS configuration for radio failure) , but does not judge whether the condition is met. May perform judgement until the action 10 as illustrated in FIG. 6A.
  • CPS configuration i.e., CPS configuration for radio failure
  • the remote UE upon receiving the CPS configuration #4, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) . And for each trigger condition of each CPS execution condition, the remote UE applies the first set of parameters. Additionally, the remote UE applies the second set of parameters.
  • the remote UE starts the evaluation/measurement based on the specific set of parameters for a trigger condition, but does not judge whether the condition is met. May perform judgement until the action 10 as illustrated in FIG. 6A.
  • the remote UE may start evaluation/measurement for CPS configuration (s) of normal case, or the remote UE may start evaluation/measurement for CPS configuration (s) of normal cases and the specific CPS configuration (s) . But does not judge whether the condition is met or not until determining the radio failure cases.
  • the relay UE sends notification message to the remote UE about radio failure cases (radio failure cases: (a) HO of Relay UE, or (b) Uu RLF) , or the remote UE detects RLF of PC5 failure. In this way, the remote UE may determine the radio failure.
  • radio failure cases radio failure cases: (a) HO of Relay UE, or (b) Uu RLF)
  • the remote UE detects RLF of PC5 failure. In this way, the remote UE may determine the radio failure.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon determining radio failure cases, initiates the RRC connection reestablishment procedure and performs cell (re) selection and/or relay UE (re) selection.
  • the remote UE may stop the cell selection procedure (if ongoing) , if attemptCondReconfig/attempCondPathSwitch is configured; and/or if the selected relay UE is one of the candidate relay UE for which the reconfigurationWithSync (e.g., indicating path switch) is included in the masterCellGroup in the MCG VarConditionalReconfig. Further, the remote UE may apply the stored condRRCReconfig associated to the selected Relay UE. Else, the remote UE may send the RRCReestablishmentRequest message.
  • the reconfigurationWithSync e.g., indicating path switch
  • the above procedure is performed in case that the reconfigurationWithSync indicates path switch, such as I2I path switch.
  • path switch such as I2I path switch.
  • it includes IE sl-PathSwitchConfig or IE specific for I2I path switch.
  • new flag for CPS such as, attempCondPathSwitch, may be introduced.
  • the relay UE is the first selected Relay UE. In other words, it is the first relay selection after failure/upon determining radio failure cases.
  • the remote UE may stop the cell selection procedure, if ongoing; a legacy procedures may be performed. Additionally, a new flag for CPS, such as attempCondPathSwitch, may be introduced.
  • the legacy CHO and/or CPS configuration may be re-used.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon one of the above radio failure cases, try to select one candidate node that fulfills the specific trigger condition of radio failure cases. If the evaluation/measurement based on the specific trigger condition has been started in action 8, upon determining radio failure cases, the remote UE starts judging whether the condition is met or not. Alternatively, upon determining radio failure case, the remote UE starts the evaluation/measurement based on the specific trigger condition, and try to select one candidate node that fulfills the specific trigger condition.
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE is configured with CPS for radio failure cases
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE may select a node with a more suitable/proper link quality, and signaling overhead for updating proper candidate nodes may be saved.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon determining radio failure cases, selects one candidate node preconfigured for radio failure cases directly.
  • the remote UE upon determining radio failure cases, try to select one candidate node that fulfills the specific CPS configuration for radio failure cases. If the evaluation/measurement based on the specific CPS configuration has been started in step8, upon determining radio failure cases, the remote UE starts judging whether the condition is met or not. Alternatively, upon determining radio failure case, the remote UE starts the evaluation/measurement based on the specific CPS configuration, and try to select one candidate node that fulfills the specific trigger condition.
  • the remote UE if no candidate node is preconfigured for radio failure cases, the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE is configured with CPS for radio failure cases
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon determining radio failure cases, try to select one candidate node that fulfills the trigger condition based on its second set of parameters for radio failure cases.
  • the remote UE upon determining radio failure case, start the evaluation based on the trigger condition and its second set of parameters of radio failure cases, and try to select one candidate node that fulfills the trigger condition and its second set of parameters of radio failure cases.
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE is configured with CPS for radio failure cases
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE may select a node with a more suitable/proper link quality. And less signaling overhead for updating proper candidate nodes. Further, less interruption time for data transmission may be achieved, because the measurement may be executed once it is configured.
  • trigger event may be defined:
  • CondEvent Z1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute (threshold2-offset) .
  • CondEvent Z3 Distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold (distanceThreshFromReference2 + offset) .
  • trigger event may be defined:
  • CondEvent X1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration conditional reconfiguration candidate (NR cell) becomes better than another absolute (threshold2-offset) .
  • CondEvent4 Conditional reconfiguration candidate becomes better than absolute (threshold-offset) .
  • CondEvent X3 Distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (NR cell) becomes shorter than configured threshold (distanceThreshFromReference2 + offset) .
  • trigger event may be defined:
  • CondEvent Z1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute threshold2-1.
  • CondEvent Z3 Distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold distanceThreshFromReference2-1.
  • trigger event may be defined:
  • CondEvent X1 Serving L2 U2N relay UE becomes worse than absolute threshold1 AND conditional reconfiguration conditional reconfiguration candidate (NR cell) becomes better than another absolute threshold2-1.
  • Conditional reconfiguration candidate becomes better than absolute threshold1-1.
  • CondEvent X3 Distance between (Remote) UE and referenceLocation1 of serving L2 U2N relay UE becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (NR cell) becomes shorter than configured threshold distanceThreshFromReference2-1.
  • candidate relay UE if candidate relay UE is selected, establish PC5 connection with the selected candidate Relay UE.
  • candidate cell if candidate cell is selected, synchronizes to the selected candidate cell, performs RACH procedure.
  • FIG. 6B illustrates a signaling flow 600B of communication in accordance with some embodiments of the present disclosure.
  • the remote UE is configured with CPS configurations. Upon radio failure, the remote UE selects one candidate node which is,
  • the remote UE is configured with CPS configuration, including at least one of the following:
  • Candidate node at least one candidate cell and/or candidate Relay UE, and
  • each candidate node such as, a cell or relay UE
  • the CPS configuration follows a legacy manner. That is, the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) (with up to 2 trigger conditions) .
  • the CPS configuration is represented as CPS configuration #1.
  • the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) , wherein each execution condition consists of at least two trigger conditions.
  • each execution condition consists of at least two trigger conditions.
  • one execution condition is sued for legacy evaluation/normal case and the other execution condition is used for the radio failure case.
  • such CPS configuration is represented as CPS configuration #2.
  • the two trigger conditions may have the same or different event conditions. If the two trigger conditions have the same event condition, the latter one (i.e., the execution condition for the radio failure) may have a looser requirement for selecting candidate node, for example, a shorter time to trigger, a lower triggering threshold for selecting the candidate node.
  • the first trigger condition is used for normal evaluation
  • the second one is used for the radio failure case
  • the CPS configuration indicates at least one candidate node of the radio failure case.
  • a specific CPS configuration/CPS execution condition is configured for the radio failure case.
  • such CPS configuration is represented as CPS configuration #3.
  • the CPS configuration #3 is configured without corresponding execution conditions.
  • the CPS configuration #3 is configured with execute condition, which consists of radio failure case. In other words, define new trigger condition (s) using radio failure cases.
  • the new trigger condition maybe CondEvent #1: determining radio failure cases, such as
  • the new trigger condition maybe CondEvent #2: CondEvent #2: determining radio failure cases, such as
  • the CPS configuration #3 is configured execute condition, which consists of legacy execute condition for CHO/CPS.
  • the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) (with up to 2 trigger conditions) , where each trigger condition is configured with two sets of parameters.
  • CPS configuration #4 such CPS configuration is represented as CPS configuration #4.
  • the CPS configuration #4 indicates an offset/another hysteresis for triggering threshold and/or an offset for time to trigger, which will be used upon determining radio failure cases. Additionally, each of these offsets has a positive value.
  • the CPS configuration #4 indicates two sets of (triggering threshold (s) and/or timer to trigger) , i.e., the first set used for normal case; and the second set used upon determining radio failure cases.
  • triggering threshold (s) and/or timer to trigger i.e., the first set used for normal case; and the second set used upon determining radio failure cases.
  • parameters in the second set are of looser requirement than those in the first set.
  • the CPS configuration #4 may indicates at least one of the following:
  • CondEvent Y1 Serving cell becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute threshold2; (the first set) is configured with threshold1 and threshold2.
  • the second set configured with at least threshold2-1, where threshold2-1 ⁇ threshold2.
  • CondEvent Y2 Conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than absolute threshold; (the first set) is configured with threshold.
  • an offset/hysteresis As one example, an offset/hysteresis.
  • the second set configured with at least threshold1-1, where threshold1-1 ⁇ threshold.
  • CondEvent Y3 Distance between (Remote) UE and referenceLocation1 of serving cell becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold distanceThreshFromReference2; (the first set) is configured with distanceThreshFromReference1, distanceThreshFromReference2.
  • the second set configured with at least distanceThreshFromReference2-1, where distanceThreshFromReference2-1 >distanceThreshFromReference2.
  • the remote UE upon receiving the CPS configuration #1, the remote UE receives and stores the received CPS configuration. Upon receiving the CPS configuration, the remote UE may start evaluating the CPS execution conditions for the candidate node (s) as legacy.
  • the remote UE upon receiving the CPS configuration #1, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) based on the trigger condition of normal case. Additionally, the remote UE starts evaluating the CPS execution conditions based on the trigger condition of radio failure cases.
  • the remote UE starts the evaluation/measurement based on the specific trigger condition , but does not judge whether the condition is met. May perform judgement until the action 10 as illustrated in FIG. 6B.
  • the remote UE upon receiving the CPS configuration #3, the remote UE does not need to evaluate the CPS execution conditions for candidate node of radio failure cases.
  • the remote UE upon receiving the CPS configuration #3, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) of normal CPS configurations. Additionally, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) of the specific CPS configurations.
  • the remote UE starts the evaluation/measurement based on the specific CPS configuration, but does not judge whether the condition is met. May perform judgement until the action 10 as illustrated in FIG. 6B.
  • the remote UE upon receiving the CPS configuration #4, the remote UE starts evaluating the CPS execution conditions for the candidate node (s) . And for each trigger condition of each CPS execution condition, the remote UE applies the first set of parameters. Additionally, the remote UE applies the second set of parameters.
  • the remote UE starts the evaluation/measurement based on the specific set of parameters for a trigger condition, but does not judge whether the condition is met. May perform judgement until the action 10 as illustrated in FIG. 6B.
  • the remote UE may start evaluation/measurement for CPS configuration (s) of normal case, or he remote UE may start evaluation/measurement for CPS configuration (s) of normal cases and the specific CPS configuration (s) . But does not judge whether the condition is met or not until determining the radio failure cases.
  • the remote UE detects RLF of PC5 failure. In this way, the remote UE may determine the radio failure.
  • the remote UE upon determining radio failure cases, initiates the RRC connection reestablishment procedure and performs cell (re) selection and/or relay UE (re) selection.
  • the remote UE may stop the cell selection procedure (if ongoing) , if attemptCondReconfig/attempCondPathSwitch is configured; and/or if the selected relay UE is one of the candidate relay UE for which the reconfigurationWithSync (e.g., indicating path switch) is included in the masterCellGroup in the MCG VarConditionalReconfig. Further, the remote UE may apply the stored condRRCReconfig associated to the selected Relay UE. Else, the remote UE may send the RRCReestablishmentRequest message.
  • the reconfigurationWithSync e.g., indicating path switch
  • the above procedure is performed in case that the reconfigurationWithSync indicates path switch, such as I2I path switch.
  • path switch such as I2I path switch.
  • it includes IE sl-PathSwitchConfig or IE specific for I2I path switch.
  • new flag for CPS such as, attempCondPathSwitch, may be introduced.
  • the relay UE is the first selected Relay UE. In other words, it is the first relay selection after failure/upon determining radio failure cases.
  • the remote UE may stop the cell selection procedure, if ongoing; a legacy procedures may be performed. Additionally, a new flag for CPS, such as attempCondPathSwitch, may be introduced.
  • the legacy CHO and/or CPS configuration is re-used.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon one of the above radio failure cases, try to select one candidate node that fulfills the specific trigger condition of radio failure cases. If the evaluation/measurement based on the specific trigger condition has been started in action 8, upon determining radio failure cases, the remote UE starts judging whether the condition is met or not. Alternatively, upon determining radio failure case, the remote UE starts the evaluation/measurement based on the specific trigger condition, and try to select one candidate node that fulfills the specific trigger condition.
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE is configured with CPS for radio failure cases
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE may select a node with a more suitable/proper link quality, and signaling overhead for updating proper candidate nodes may be saved.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon determining radio failure cases, selects one candidate node preconfigured for radio failure cases directly.
  • the remote UE upon determining radio failure cases, try to select one candidate node that fulfills the specific CPS configuration for radio failure cases. If the evaluation/measurement based on the specific CPS configuration has been started in step8, upon determining radio failure cases, the remote UE starts judging whether the condition is met or not. Alternatively, upon determining radio failure case, the remote UE starts the evaluation/measurement based on the specific CPS configuration, and try to select one candidate node that fulfills the specific trigger condition.
  • the remote UE if no candidate node is preconfigured for radio failure cases, the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE is configured with CPS for radio failure cases
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE selects one candidate node and applies corresponding stored CPS configuration.
  • the remote UE upon determining radio failure cases, try to select one candidate node that fulfills the trigger condition based on its second set of parameters for radio failure cases.
  • the remote UE upon determining radio failure case, start the evaluation based on the trigger condition and its second set of parameters of radio failure cases, and try to select one candidate node that fulfills the trigger condition and its second set of parameters of radio failure cases.
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE is configured with CPS for radio failure cases
  • the remote UE initiates the RRC connection reestablishment procedure.
  • the remote UE may select a node with a more suitable/proper link quality. And less signaling overhead for updating proper candidate nodes. Further, less interruption time for data transmission may be achieved, because the measurement may be executed once it is configured.
  • trigger event may be defined:
  • CondEvent Y1 Serving cell becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute (threshold2-offset) ;
  • CondEvent Y2 Conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than absolute (threshold-offset) ;
  • CondEvent Y3 Distance between (Remote) UE and referenceLocation1 of serving cell becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold (distanceThreshFromReference2 + offset) .
  • trigger event may be defined:
  • CondEvent Y1 Serving cell becomes worse than absolute threshold1 AND conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than another absolute threshold2-1;
  • CondEvent Y2 Conditional reconfiguration candidate (L2 U2N Relay UE) becomes better than absolute threshold1-1;
  • CondEvent Y3 Distance between (Remote) UE and referenceLocation1 of serving cell becomes larger than configured threshold distanceThreshFromReference1 and distance between UE and referenceLocation2 of a conditional reconfiguration candidate (L2 U2N Relay UE) becomes shorter than configured threshold distanceThreshFromReference2-1.
  • candidate relay UE if candidate relay UE is selected, establish PC5 connection with the selected candidate Relay UE.
  • candidate cell if candidate cell is selected, synchronizes to the selected candidate cell, performs RACH procedure.
  • FIG. 6C illustrates a signaling flow 600C of communication in accordance with some embodiments of the present disclosure.
  • the relay UE is configured with CPS configuration. Upon radio failure cases, the relay UE forwards CPS configuration to the remote UE, and then the remote UE selects the preconfigured candidate node for radio failure cases or perform evaluation to select a candidate node.
  • the relay UE is configured with CPS configuration, including at least one of the following:
  • Candidate node at least one candidate cell and/or candidate Relay UE, and
  • each candidate node such as cell or Relay UE.
  • the CPS configuration follows a legacy manner. That is, the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) (with up to 2 trigger conditions) .
  • the CPS configuration is represented as CPS configuration #1.
  • the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) , wherein each execution condition consists of at least two trigger conditions.
  • each execution condition consists of at least two trigger conditions.
  • one execution condition is sued for legacy evaluation/normal case and the other execution condition is used for the radio failure case.
  • such CPS configuration is represented as CPS configuration #2.
  • the two trigger conditions may have the same or different event conditions. If the two trigger conditions have the same event condition, the latter one (i.e., the execution condition for the radio failure) may have a looser requirement for selecting candidate node, for example, a shorter time to trigger, a lower triggering threshold for selecting the candidate node.
  • the first trigger condition is used for normal evaluation
  • the second one is used for the radio failure case
  • the CPS configuration indicates at least one candidate node of the radio failure case.
  • a specific CPS configuration/CPS execution condition is configured for the radio failure case.
  • such CPS configuration is represented as CPS configuration #3.
  • the CPS configuration #3 is configured without corresponding execution conditions.
  • the CPS configuration #3 is configured with execute condition, which consists of radio failure case. In other words, define new trigger condition (s) using radio failure cases.
  • the new trigger condition maybe CondEvent #1: determining radio failure cases, such as,
  • the new trigger condition maybe CondEvent #2: CondEvent #2: determining radio failure cases, such as,
  • the CPS configuration #3 is configured execute condition, which consists of legacy execute condition for CHO/CPS.
  • the CPS configuration indicates a candidate node (s) and a corresponding execution condition (s) (with up to 2 trigger conditions) , where each trigger condition is configured with two sets of parameters.
  • CPS configuration #4 such CPS configuration is represented as CPS configuration #4.
  • the CPS configuration #4 indicates an offset/another hysteresis for triggering threshold and/or an offset for time to trigger, which will be used upon determining radio failure cases. Additionally, each of these offsets has a positive value.
  • the CPS configuration #4 indicates two sets of (triggering threshold (s) and/or timer to trigger) , i.e., the first set used for normal case; and the second set used upon determining radio failure cases.
  • triggering threshold (s) and/or timer to trigger i.e., the first set used for normal case; and the second set used upon determining radio failure cases.
  • parameters in it are of looser requirement than those in the first set.
  • the relay UE stores the received CPS configuration.
  • the relay UE is configured with CPS configuration, such as case1-1 step6 alt 3.2, to trigger the forwarding of received signallings.
  • the relay UE is configured with normal PS commands for the remote UEs.
  • the S-gNB may send RRCReconfiguration for each the remote UE separately.
  • the S-gNB may send a common configuration of the remote UEs in the same cell or gNB.
  • the relay UE Upon detecting Uu RLF or receiving HO command of itself, the relay UE sends CPS configuration/normal PS command to the remote UE (for which the CPS configuration has been received in action 6) , via such as, PC5-RRC signalling, for example, in a RRC container.
  • relay UE upon execute condition corresponding to radio failure cases is met, sends CPS configuration/normal PS command to the remote UE.
  • the remote UE applies the received configuration, such as apply the configuration of preconfigured candidate node for radio failure case.
  • the remote UE performs evaluation on execution conditions and try to select one candidate node that fulfills the requirement.
  • the remote UE performs evaluation on trigger conditions for radio failure cases try to select one candidate node that fulfills the requirement.
  • the remote UE performs evaluation on trigger conditions and its second set of parameters for radio failure cases try to select one candidate node that fulfills the requirement.
  • the remote UE applies the normal PS command.
  • candidate relay UE if candidate relay UE is selected, establish PC5 connection with the selected candidate Relay UE.
  • candidate cell if candidate cell is selected, synchronizes to the selected candidate cell, performs RACH procedure.
  • relay UE Upon HO/Uu RLF, relay UE forwards normal PS command for the remote UE.
  • relay UE Upon HO/Uu RLF, relay UE forwards CPS command for the remote UE.
  • relay UE Upon CPS of relay UE is met, relay UE forwards normal PS command for the remote UE.
  • relay UE Upon CPS of relay UE is met, relay UE forwards CPS command for the remote UE.
  • FIG. 7 illustrates a signaling flow 700 of communication in accordance with some embodiments of the present disclosure.
  • S-gNB requests one or more candidate Relay UEs belonging to one or more candidate gNBs, via Xn message, such as, new Xn message, or a legacy Xn message such as HANDOVER REQUEST.
  • Xn message such as, new Xn message, or a legacy Xn message such as HANDOVER REQUEST.
  • a new IE for CPS may be introduced, such as Conditional Path Switching Information Request.
  • CPS trigger may be indicated, such as, CPS initiate, CPS replace, CPS modify, CPS release and so on.
  • types of CPS may be indicated, such as, D2I, I2D, I2I.
  • gNB i.e., a list of candidate Relay UEs for more than one cells per new IE.
  • the candidate gNB (s) sends CPS response (Xn message) including configuration of CPS candidate Relay UEs to the source gNB, via an Xn message, such as, a new Xn message, or legacy Xn message such as HANDOVER REQUEST ACKNOWLEDGE.
  • the Xn message consists of at least one of: a new IE for CPS, and the serving cell of Candidate Relay UE.
  • the new IE for CPS such as Conditional Path Switching Information Acknowledge, which includes: ID of requested (prepared) Relay UE, and its corresponding relay related configuration.
  • the relay UE information may be indicated by the following:
  • the CPS response message is sent for each candidate Relay UE;
  • the CPS response message is sent for each cell, and each response including candidate Relay UEs for one cell; multiple Relay UEs are requested by one Xn message or multiple Xn messages;
  • the target NG-RAN node shall include the Requested Target relay UE ID IE in the HANDOVER PREPARATION FAILURE message.
  • the target NG-RAN node shall include the ID of at least one requested relay UE in the HANDOVER PREPARATION FAILURE message.
  • a cause value in the HANDOVER PREPARATION FAILURE message may be: Mobility/handover of Candidate Relay UE, or No Radio Resources Available in candidate Relay UE.
  • the S-gNB sends a message to T-gNB to cancel an ongoing CPS/PS/handover preparation or an already prepared CPS/PS/handover, via an Xn message, such as, a new Xn message, or a legacy Xn message such as HANDOVER CANCEL.
  • an Xn message such as, a new Xn message, or a legacy Xn message such as HANDOVER CANCEL.
  • the Xn message consists of at least one of, the new Xn message consists at least the first 2 IEs/Fields , the new IE for CPS, and source NG-RAN node UE XnAP ID, a cause, a target NG-RAN node UE XnAP ID, the serving cell of Candidate Relay UE.
  • the new IE for CPS such as Candidate Relay Ues To Be Cancelled List, which may include: ID of requested (prepared) Relay UE, e.g., Layer2 ID, 24bits.
  • parameter of maxnoofCellsinCHO or maxnoofRelayUesinCPS may refer to the maximum number of relay UEs that can be prepared for a conditional path switching, the value of which may be 32*N or 8*N.
  • the source gNB may use an indication to cancel all Relay UEs.
  • the cause value may be Mobility/handover of S-Relay UE.
  • the target NG-RAN node sends a message to T-gNB to cancel an ongoing CPS/PS/handover preparation or an already prepared CPS/PS/handover.
  • the target NG-RAN node if the Candidate Relay Ues To Be Cancelled List IE is included in the HANDOVER CANCEL message, the target NG-RAN node shall consider that the source NG-RAN node is cancelling only the handover/PS/CPS associated to the candidate Relay UEs identified by the included relay UE ID and associated to the same UE-associated signaling connection identified by the Source NG-RAN node UE XnAP ID IE and, if included, also by the Target NG-RAN node UE XnAP ID IE.
  • T-gNB sends a message to S-gNB to cancel an ongoing CPS/PS/handover preparation or an already prepared CPS/PS/handover, via an Xn message, such as, a new Xn message such as CONDITIONAL PATH SWITCHING/SWITCH CANCEL, or a legacy Xn message such as CONDITIONAL HANDOVER CANCEL.
  • Xn message such as, a new Xn message such as CONDITIONAL PATH SWITCHING/SWITCH CANCEL, or a legacy Xn message such as CONDITIONAL HANDOVER CANCEL.
  • the Xn message consists of at least one of : the new Xn message consists at least the first 3/4 IEs/Fields , the new IE for CPS, the source NG-RAN node UE XnAP ID, the target NG-RAN node UE XnAP ID, a cause, the serving cell of Candidate Relay UE.
  • the new IE for CPS such as Candidate Relay Ues To Be Cancelled List, which may include: ID of requested (prepared) Relay UE, e.g., Layer2 ID, 24bits.
  • parameter of maxnoofCellsinCHO or maxnoofRelayUesinCPS may refer to the maximum number of relay UEs that can be prepared for a conditional path switching, the value of which may be 32*N or 8*N.
  • the target gNB may use an indication to cancel all Relay UEs.
  • a cause value may be mobility/handover of Candidate Relay UE, no Radio Resources Available in candidate Relay UE, or CPS resources to be changed.
  • T-gNB sends a message to S-gNB to cancel an ongoing CPS/PS/handover preparation or an already prepared CPS/PS/handover.
  • the source NG-RAN node at the reception of the CONDITIONAL HANDOVER CANCEL/CONDITIONAL PATH SWITCH CANCEL message, the source NG-RAN node shall consider that the target NG-RAN node is about to remove any reference to, and release any resources previously reserved for candidate Relay UEs associated to the UE-associated signalling identified by the Source NG-RAN node UE XnAP ID IE and the Target NG-RAN node UE XnAP ID IE.
  • the source NG-RAN node shall consider that only the resources reserved for the Relay UEs identified by the included relay UE ID are about to be released.
  • FIG. 8 illustrates a signaling flow 800 of communication in accordance with some embodiments of the present disclosure.
  • S-gNB requests one or more candidate cells belonging to one or more candidate gNBs, via an Xn message, such as, a new Xn message, or a legacy Xn message such as HANDOVER REQUEST.
  • Xn message such as, a new Xn message, or a legacy Xn message such as HANDOVER REQUEST.
  • the Xn message may comprise a legacy IE of CHO, such as, Conditional Handover Information Request.
  • the source gNB may reuse Conditional Handover Information Request to request candidate cell for CPS, and the C-gNB prepares configuration of candidate cell, S-gNB decides execution conditions.
  • the Xn message may comprise a new IE for CPS, such as Conditional Path Switching Information Request.
  • the Xn message may indicate CPS trigger, which may be CPS initiate, CPS replace, CPS modify, CPS release and so on.
  • the Xn message may indicate types of CPS, which may be D2I, I2D, I2I.
  • the candidate gNB (s) sends CPS/CHO response (Xn message) including configuration of CPS candidate Relay UEs to the source gNB via an Xn message, such as, a new Xn message, or a legacy Xn message such as HANDOVER REQUEST ACKNOWLEDGE.
  • the Xn message may comprise a legacy IE of CHO, such as Conditional Handover Information Acknowledge.
  • the target gNB may reuse Conditional Handover Information Acknowledge to provide candidate cell for CPS.
  • the Xn message may comprise a new IE for CPS, such as, Conditional Path Switching Information Acknowledge.
  • FIG. 9 illustrates a flowchart of a communication method 900 implemented at a remote terminal device in accordance with some embodiments of the present disclosure.
  • the method 900 will be described from the perspective of the remote terminal device 110 in FIG. 1A.
  • the remote terminal device 110 receives, from a first network device serving the remote terminal device 110, conditional path switch configuration information used for switching the remote terminal device 110 from a first path to a second path. At least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario.
  • the remote terminal device 110 determines, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • the remote terminal device 110 performs at least one of the following: starting measurements on the at least one first candidate node, determining whether a first switching condition of the at least one first switching condition is met based on measurement results of the at least one first candidate node, wherein at least part of the measurement results are obtained prior to determining the path failure, or determining a first candidate node based on determinations about whether a first switching condition of the at least one first switching condition is met, wherein the determinations are obtained prior to determining the path failure.
  • conditional path switch configuration information further indicates: second information indicating at least one second switching condition corresponding to at least one second candidate node comprising a candidate cell or a candidate relay terminal device, the second information being associated with a normal path switch scenario.
  • the second information corresponds to a second path switch configuration and the first information corresponds to a first path switch configuration different from the second path switch configuration, the second information corresponds a second conditional trigger event associated with a path switch configuration, and the first information corresponds a first conditional trigger event associated with the same path switch configuration, or the second information corresponds a second parameter set associated with a conditional trigger event, and the first information corresponds a first parameter set associated with the same conditional trigger event.
  • At least one of the following is determined based on a default rule or an indication configured by the first network device: a correspondence between the first and second path switch configurations and the normal and path failure scenarios, a correspondence between the first and second conditional trigger events and the normal and path failure scenarios, a correspondence between the first and second parameter sets and the normal and path failure scenarios.
  • the first path switch configuration indicates at least one of the following: a first candidate node without being configured with execution condition, or a first candidate node being configured with a conditional trigger event being at least one of the following: being notified with a handover of a relay terminal device that is serving the remote terminal device 110, being notified with a Uu radio link failure (RLF) of the relay terminal device, being notified with a cell re-selection of the relay terminal device, or detecting a PC5 RLF.
  • RLF radio link failure
  • the remote terminal device 110 detects the path failure in response to receiving, from a relay terminal device that is serving the remote terminal device 110, a notification message indicating at least one of the following: a Uu radio link failure (RLF) of the relay terminal device, a cell re-selection of the relay terminal device, or a handover of the relay terminal device.
  • a relay terminal device that is serving the remote terminal device 110
  • a notification message indicating at least one of the following: a Uu radio link failure (RLF) of the relay terminal device, a cell re-selection of the relay terminal device, or a handover of the relay terminal device.
  • RLF Uu radio link failure
  • first requirements associated with the first conditional trigger event is lower than second requirements associated with the second conditional trigger event, or third requirements associated with the first parameter set is lower than fourth requirements associated with the second parameter set.
  • the first parameter set is represented as an offset set relative to the second parameter set.
  • the remote terminal device 110 cause the remote terminal device receives, from the first network device, an indication indicating whether the first information is available in response to the path failure.
  • the remote terminal device 110 cause the remote terminal device transmits a reestablishment message in response to at least one of the following: not receiving an indication indicating whether the first information is available in response to the path failure, or not receiving the first information.
  • FIG. 10 illustrates a flowchart of a communication method 1000 implemented at a first network device, in accordance with some embodiments of the present disclosure.
  • the method 1000 will be described from the perspective of the first network device 120-1 in FIG. 1A.
  • the first network device 120-1 transmits, to a remote terminal device or a relay terminal device that is serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario.
  • conditional path switch configuration information further indicates: second information indicating at least one second switching condition corresponding to at least one second candidate node comprising a candidate cell or a candidate relay terminal device, the second information being associated with a normal path switch scenario.
  • the second information corresponds to a second path switch configuration and the first information corresponds to a first path switch configuration different from the second path switch configuration, the second information corresponds a second conditional trigger event associated with a path switch configuration, and the first information corresponds a first conditional trigger event associated with the same path switch configuration, or the second information corresponds a second parameter set associated with a conditional trigger event, and the first information corresponds a first parameter set associated with the same conditional trigger event.
  • At least one of the following is determined based on a default rule or an indication configured by the first network device 120-1: a correspondence between the first and second path switch configurations and the normal and path failure scenarios, a correspondence between the first and second conditional trigger events and the normal and path failure scenarios, a correspondence between the first and second parameter sets and the normal and path failure scenarios.
  • the first path switch configuration indicates at least one of the following: a first candidate node without being configured with execution condition, or a first candidate node being configured with a conditional trigger event being at least one of the following: being notified with a handover of a relay terminal device that is serving the remote terminal device, being notified with a Uu radio link failure (RLF) of the relay terminal device, being notified with a cell re-selection of the relay terminal device, or detecting a PC5 RLF.
  • RLF radio link failure
  • the first network device 120-1 transmits, to the remote terminal device, a notification message indicating at least one of the following: a Uu radio link failure (RLF) of the relay terminal device, a cell re-selection of the relay terminal device, or a handover of the relay terminal device.
  • RLF Uu radio link failure
  • first requirements associated with the first conditional trigger event is lower than second requirements associated with the second conditional trigger event, or third requirements associated with the first parameter set is lower than fourth requirements associated with the second parameter set.
  • the first parameter set is represented as an offset set relative to the second parameter set.
  • the first network device 120-1 transmits, to the remote device, an indication indicating whether the first information is available in response to the path failure.
  • the remote terminal device 110 initiates a reestablishment procedure to determine an available candidate node.
  • FIG. 15 illustrates a flowchart of a communication method 1500 implemented at a second network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1500 will be described from the perspective of the second network device 120-2 in FIG. 1A.
  • the second network device 120-2 transmits, to the first network device, preparation response to the preparation request, the preparation response being associated with at least one of the following: one candidate relay device served by a second network device 120-2, a first set of candidate relay devices served by the second network device 120-2, or a second set of candidate relay devices served by a cell provided by the second network device 120-2.
  • the preparation response is a request acknowledge or a preparation failure.
  • the preparation failure indicates at least one candidate relay device with a preparation failure
  • a cause value for the preparation failure of a candidate relay device of the at least one candidate relay device is one of the following: lacking available radio resources for the candidate relay device, the candidate relay device being not available, or the candidate relay device performing a handover.
  • the second network device 120-2 after transmitting the handover request acknowledge, transmits a second cancel message to the first network device, the second cancel message comprising: an indication used for cancelling preparation for all the candidate relay devices served by the second network device 120-2s, an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell, or a set of terminal device identifiers corresponding to a set of candidate relay devices to be cancelled.
  • the number of candidate relay terminal device indicated by the first or second cancel message is a multiple of a predefined number.
  • FIG. 16 is a simplified block diagram of a device 1600 that is suitable for implementing embodiments of the present disclosure.
  • the device 1600 can be considered as a further example implementation of any of the devices as shown in FIG. 1A. Accordingly, the device 1600 can be implemented at or as at least a part of the remote terminal device 110, the first network device 120-1, the second network device 120-2 and/or the relay terminal device 130.
  • the device 1600 includes a processor 1610, a memory 1620 coupled to the processor 1610, a suitable transceiver 1640 coupled to the processor 1610, and a communication interface coupled to the transceiver 1640.
  • the memory 1620 stores at least a part of a program 1630.
  • the transceiver 1640 may be for bidirectional communications or a unidirectional communication based on requirements.
  • the transceiver 1640 may include at least one of a transmitter 1642 and a receiver 1644.
  • the transmitter 1642 and the receiver 1644 may be functional modules or physical entities.
  • the transceiver 1640 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones.
  • the communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.
  • MME Mobility Management Entity
  • AMF Access and Mobility Management Function
  • RN relay node
  • Uu interface for communication between the eNB/gNB and a terminal device.
  • the program 1630 is assumed to include program instructions that, when executed by the associated processor 1610, enable the device 1600 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGS. 1A to 16.
  • the embodiments herein may be implemented by computer software executable by the processor 1610 of the device 1600, or by hardware, or by a combination of software and hardware.
  • the processor 1610 may be configured to implement various embodiments of the present disclosure.
  • a combination of the processor 1610 and memory 1620 may form processing means 1650 adapted to implement various embodiments of the present disclosure.
  • the memory 1620 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 1620 is shown in the device 1600, there may be several physically distinct memory modules in the device 1600.
  • the processor 1610 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.
  • the device 1600 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.
  • a remote terminal device comprising a circuitry.
  • the circuitry is configured to: receive, from a first network device serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario; and in response to determining a path failure, determine, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • the circuitry may be configured to perform any method implemented by the remote terminal device as discussed above.
  • a first network device comprising a circuitry.
  • the circuitry is configured to: transmit, to a remote terminal device or a relay terminal device that is serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, wherein the first information being associated with a path failure scenario.
  • the circuitry may be configured to perform any method implemented by the first network device, as discussed above.
  • a relay terminal device comprising a circuitry.
  • the circuitry is configured to: receive, from a first network device serving a remote terminal device, conditional path switch configuration information used for switching the remote terminal device from an indirect path to a further path, the remote terminal device communicating with the first network device via the first path associated with the relay terminal device, the conditional path switch configuration information indicating at least one switching condition corresponding to at least one candidate node comprising a candidate cell or a candidate relay terminal device, the conditional path switch configuration information being associated with a path failure scenario; and in response to determining a radio link failure (RLF) with the first network device, transmit the conditional path switch configuration information to the remote terminal device.
  • RLF radio link failure
  • the circuitry may be configured to perform any method implemented by the relay terminal device as discussed above.
  • a remote terminal device comprising a circuitry.
  • the circuitry is configured to: receive, from a first network device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates at least one candidate node to be switched to, and the at least one candidate node comprises a candidate cell or a candidate relay terminal device; in response to determining a path failure, initiate a reestablishment procedure to determine an available candidate node; and trigger, based on the conditional path switch configuration information, a switch to the second path associated with the available candidate node in accordance with a determination that the available candidate node is comprised in the at least one candidate node.
  • the circuitry may be configured to perform any method implemented by the remote terminal device as discussed above.
  • a first network device comprising a circuitry.
  • the circuitry is configured to: transmit, to a remote terminal device, conditional path switch configuration information and an indication, wherein, the conditional path switch configuration information is used for switching the remote terminal device from a first path to a second path, at least one of the first and second paths being indirect path; the indication indicates whether the conditional path switch configuration information is available in response to a path failure.
  • the circuitry may be configured to perform any method implemented by the first network device as discussed above.
  • a first network device comprising a circuitry.
  • the circuitry is configured to: generate, a preparation request for a conditional path switch, the preparation request being associated with at least one of candidate relay device served by a second network device; and transmit the preparation request to the second network device.
  • the circuitry may be configured to perform any method implemented by the first network device as discussed above.
  • a second network device comprising a circuitry.
  • the circuitry is configured to: receive, from a first network device, a preparation request for a conditional path switch for a remote terminal device, wherein the first network device is serving the remote terminal device and wherein the preparation request is associated with at least one of candidate relay device served by a second network device.
  • the circuitry may be configured to perform any method implemented by the second network device as discussed above.
  • circuitry used herein may refer to hardware circuits and/or combinations of hardware circuits and software.
  • the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware.
  • the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions.
  • the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation.
  • the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.
  • a remote terminal apparatus comprises means for receiving, from a first network device serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario; and means for in response to determining a path failure, determining, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • the first apparatus may comprise means for performing the respective operations of the method 900. In some example embodiments, the first apparatus may further comprise means for performing other operations in some example embodiments of the method 900.
  • the means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
  • a first network apparatus comprises means for transmitting, to a remote terminal device or a relay terminal device that is serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, wherein the first information being associated with a path failure scenario.
  • the second apparatus may comprise means for performing the respective operations of the method 1000.
  • the second apparatus may further comprise means for performing other operations in some example embodiments of the method 1000.
  • the means may be implemented in any suitable form.
  • the means may be implemented in a circuitry or software module.
  • a relay terminal apparatus comprises means for receiving, from a first network device serving a remote terminal device, conditional path switch configuration information used for switching the remote terminal device from an indirect path to a further path, the remote terminal device communicating with the first network device via the first path associated with the relay terminal device, the conditional path switch configuration information indicating at least one switching condition corresponding to at least one candidate node comprising a candidate cell or a candidate relay terminal device, the conditional path switch configuration information being associated with a path failure scenario; and means for in response to detecting a radio link failure (RLF) with the first network device, transmitting the conditional path switch configuration information to the remote terminal device.
  • RLF radio link failure
  • the third apparatus may comprise means for performing the respective operations of the method 1100. In some example embodiments, the third apparatus may further comprise means for performing other operations in some example embodiments of the method 1100.
  • the means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
  • a remote terminal apparatus comprises means for receiving, from a first network device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates at least one candidate node to be switched to, and the at least one candidate node comprises a candidate cell or a candidate relay terminal device; means for in response to determining a path failure, initiating a reestablishment procedure to determine an available candidate node; and means for triggering, based on the conditional path switch configuration information, a switch to the second path associated with the available candidate node in accordance with a determination that the available candidate node is comprised in the at least one candidate node.
  • the fourth apparatus may comprise means for performing the respective operations of the method 1200. In some example embodiments, the fourth apparatus may further comprise means for performing other operations in some example embodiments of the method 1200.
  • the means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
  • a first network apparatus comprises means for transmitting, to a remote terminal device, conditional path switch configuration information and an indication, wherein, the conditional path switch configuration information is used for switching the remote terminal device from a first path to a second path, at least one of the first and second paths being indirect path; the indication indicates whether the conditional path switch configuration information is available in response to a path failure.
  • the fifth apparatus may comprise means for performing the respective operations of the method 1300.
  • the fifth apparatus may further comprise means for performing other operations in some example embodiments of the method 1300.
  • the means may be implemented in any suitable form.
  • the means may be implemented in a circuitry or software module.
  • a first network apparatus comprises means for generating, a preparation request for a conditional path switch, the preparation request being associated with at least one of candidate relay device served by a second network device; and means for transmitting the preparation request to the second network device.
  • the sixth apparatus may comprise means for performing the respective operations of the method 1400.
  • the sixth apparatus may further comprise means for performing other operations in some example embodiments of the method 1400.
  • the means may be implemented in any suitable form.
  • the means may be implemented in a circuitry or software module.
  • a second network apparatus comprises means for receiving, from a first network device, a preparation request for a conditional path switch for a remote terminal device, wherein the first network device is serving the remote terminal device and wherein the preparation request is associated with at least one of candidate relay device served by a second network device.
  • the seventh apparatus may comprise means for performing the respective operations of the method 1500.
  • the seventh apparatus may further comprise means for performing other operations in some example embodiments of the method 1500.
  • the means may be implemented in any suitable form.
  • the means may be implemented in a circuitry or software module.
  • embodiments of the present disclosure provide the following aspects.
  • a remote terminal device comprising: a processor configured to cause the remote terminal device to: receive, from a first network device serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, the first information being associated with a path failure scenario; and in response to detecting a path failure, determine, from the at least one first candidate node, a first candidate node as a target node if a corresponding first switching condition is met.
  • the processor is further configured to cause the remote terminal device to: in response to determining the path failure, perform at least one of the following: starting measurements on the at least one first candidate node, determining whether a first switching condition of the at least one first switching condition is met based on measurement results of the at least one first candidate node, wherein at least part of the measurement results are obtained prior to determining the path failure, or determining a first candidate node based on determinations about whether a first switching condition of the at least one first switching condition is met, wherein the determinations are obtained prior to determining the path failure.
  • conditional path switch configuration information further indicates: second information indicating at least one second switching condition corresponding to at least one second candidate node comprising a candidate cell or a candidate relay terminal device, the second information being associated with a normal path switch scenario.
  • the second information corresponds to a second path switch configuration and the first information corresponds to a first path switch configuration different from the second path switch configuration, the second information corresponds a second conditional trigger event associated with a path switch configuration, and the first information corresponds a first conditional trigger event associated with the same path switch configuration, or the second information corresponds a second parameter set associated with a conditional trigger event, and the first information corresponds a first parameter set associated with the same conditional trigger event.
  • the processor is further configured to cause the remote terminal device to: detect the path failure in response to receiving, from a relay terminal device that is serving the remote terminal device, a notification message indicating at least one of the following: a Uu radio link failure (RLF) of the relay terminal device, a cell re-selection of the relay terminal device, or a handover of the relay terminal device.
  • RLF Uu radio link failure
  • the first parameter set is represented as an offset set relative to the second parameter set.
  • the processor is further configured to cause the remote terminal device to: receive, from the first network device, an indication indicating whether the first information is available in response to the path failure.
  • the processor is further configured to cause the remote terminal device to: transmit a reestablishment message in response to at least one of the following: not receiving an indication indicating whether the first information is available in response to the path failure, or not receiving the first information.
  • a first network device comprising: a processor configured to cause the first network device to: transmit, to a remote terminal device or a relay terminal device that is serving the remote terminal device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates: first information indicating at least one first switching condition corresponding to at least one first candidate node comprising a candidate cell or a candidate relay terminal device, wherein the first information being associated with a path failure scenario.
  • conditional path switch configuration information further indicates: second information indicating at least one second switching condition corresponding to at least one second candidate node comprising a candidate cell or a candidate relay terminal device, the second information being associated with a normal path switch scenario.
  • the second information corresponds to a second path switch configuration and the first information corresponds to a first path switch configuration different from the second path switch configuration, the second information corresponds a second conditional trigger event associated with a path switch configuration, and the first information corresponds a first conditional trigger event associated with the same path switch configuration, or the second information corresponds a second parameter set associated with a conditional trigger event, and the first information corresponds a first parameter set associated with the same conditional trigger event.
  • At least one of the following is determined based on a default rule or an indication configured by the first network device: a correspondence between the first and second path switch configurations and the normal and path failure scenarios, a correspondence between the first and second conditional trigger events and the normal and path failure scenarios, a correspondence between the first and second parameter sets and the normal and path failure scenarios.
  • the first path switch configuration indicates at least one of the following: a first candidate node without being configured with execution condition, or a first candidate node being configured with a conditional trigger event being at least one of the following: being notified with a handover of a relay terminal device that is serving the remote terminal device, being notified with a Uu radio link failure (RLF) of the relay terminal device, being notified with a cell re-selection of the relay terminal device, or detecting a PC5 RLF.
  • RLF radio link failure
  • the processor is further configured to cause the first network device to: transmit, to the remote terminal device, a notification message indicating at least one of the following: a Uu radio link failure (RLF) of the relay terminal device, a cell re-selection of the relay terminal device, or a handover of the relay terminal device.
  • RLF Uu radio link failure
  • first requirements associated with the first conditional trigger event is lower than second requirements associated with the second conditional trigger event, or third requirements associated with the first parameter set is lower than fourth requirements associated with the second parameter set.
  • the first parameter set is represented as an offset set relative to the second parameter set.
  • the processor is further configured to cause the first network device to: transmit, to the remote device, an indication indicating whether the first information is available in response to the path failure.
  • a relay terminal device comprising: a processor configured to cause the relay terminal device to: receive, from a first network device serving a remote terminal device, conditional path switch configuration information used for switching the remote terminal device from an indirect path to a further path, the remote terminal device communicating with the first network device via the first path associated with the relay terminal device, the conditional path switch configuration information indicating at least one switching condition corresponding to at least one candidate node comprising a candidate cell or a candidate relay terminal device, the conditional path switch configuration information being associated with a path failure scenario; and in response to detecting a radio link failure (RLF) with the first network device, transmit the conditional path switch configuration information to the remote terminal device.
  • RLF radio link failure
  • the processor is further configured to cause the relay terminal device to: determine the path failure in response to at least one of the following: a handover of the relay terminal device, Uu RLF with the first network device, or a cell re-selection procedure of the relay terminal device.
  • a remote terminal device comprising: a processor configured to cause the remote terminal device to: receive, from a first network device, conditional path switch configuration information used for switching the remote terminal device from a first path to a second path, wherein at least one of the first and second paths is indirect path and the conditional path switch configuration information indicates at least one candidate node to be switched to, and the at least one candidate node comprises a candidate cell or a candidate relay terminal device; in response to determining a path failure, initiate a reestablishment procedure to determine an available candidate node; and trigger, based on the conditional path switch configuration information, a switch to the second path associated with the available candidate node in accordance with a determination that the available candidate node is comprised in the at least one candidate node.
  • the processor is further configured to cause the remote terminal device to: transmit, a reestablishment message to the available candidate node in accordance with a determination that the available candidate node is not comprised in the at least one candidate node.
  • the processor is further configured to cause the remote terminal device to: receive, from the network device, an indication indicating whether the conditional path switch configuration information is available in response to the path failure.
  • the processor is further configured to cause the remote terminal device to: trigger a switch to the second path if the indication indicates the conditional path switch configuration information is available in response to the path failure.
  • the available candidate node is the first candidate node detected during the reestablishment procedure.
  • the processor is further configured to cause the remote terminal device to: determine the path failure in response to at least one of the following: being notified with a handover of a relay terminal device that is serving the remote terminal device, being notified with a Uu radio link failure (RLF) of the relay terminal device, being notified with a cell re-selection of the relay terminal device, detecting a Uu RLF, or detecting a PC5 RLF.
  • RLF radio link failure
  • a first network device comprising: a processor configured to cause the first network device to: transmit, to a remote terminal device, conditional path switch configuration information and an indication, wherein, the conditional path switch configuration information is used for switching the remote terminal device from a first path to a second path, at least one of the first and second paths being indirect path; the indication indicates whether the conditional path switch configuration information is available in response to a path failure.
  • a first network device comprising: a processor configured to cause the first network device to: generate, a preparation request for a conditional path switch, the preparation request being associated with at least one of candidate relay device served by a second network device; and transmit the preparation request to the second network device.
  • the at least one of candidate relay device is one of the following: one candidate relay device served by the second network device, a first set of candidate relay devices served by the second network device, or a second set of candidate relay devices served by a cell provided by the second network device.
  • the processor is further configured to cause the first network device to: transmit the preparation request in response to an initiation of the conditional path switch, or an update of the conditional path switch.
  • the preparation request indicates a type of the conditional path switch being one of the following: from a direct path to an indirect path, or from an indirect path to an indirect path.
  • the preparation request is comprised in a handover request.
  • the processor is further configured to cause the first network device to: receive, from the second network device, a response to the preparation request, the preparation response being associated with at least one of the following: failure indication, one candidate relay device served by a second network device, a first set of candidate relay devices served by the second network device, or a second set of candidate relay devices served by a cell provided by the second network device.
  • the preparation response is a request acknowledge or a preparation failure.
  • the preparation failure indicates at least one candidate relay device with a preparation failure
  • a cause value for the preparation failure of a candidate relay device of the at least one candidate relay device is one of the following: lacking available radio resources for the candidate relay device, the candidate relay device being not available, or the candidate relay device performing a handover.
  • the processor is further configured to cause the first network device to: after transmitting the preparation request, transmit a first cancel message to the second network device, the first cancel message comprising at least one of the following: an indication used for cancelling preparation for all the candidate relay devices served by the second network device, an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell, or a set of terminal device identifiers corresponding to a set of candidate relay devices to be cancelled.
  • the processor is further configured to cause the first network device to: after receiving the handover request acknowledge, receive a second cancel message from the second network device, the second cancel message comprising: an indication used for cancelling preparation for all the candidate relay devices served by the second network device, an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell, or a set of terminal device identifiers corresponding to a set of candidate relay devices to be cancelled.
  • the number of candidate relay terminal device indicated by the first or second cancel message is a multiple of a predefined number.
  • a second network device comprising: a processor configured to cause the second network device to: receive, from a first network device, a preparation request for a conditional path switch for a remote terminal device, wherein the first network device is serving the remote terminal device and wherein the preparation request is associated with at least one of candidate relay device served by a second network device.
  • the at least one of candidate relay device is one of the following: one candidate relay device served by the second network device, a first set of candidate relay devices served by the second network device, or a second set of candidate relay devices served by a cell provided by the second network device.
  • the preparation request indicates a type of the conditional path switch being one of the following: from a direct path to an indirect path, or from an indirect path to an indirect path.
  • the preparation request is comprised in a handover request.
  • the processor is further configured to cause the second network device to: transmit, to the first network device, preparation response to the preparation request, the preparation response being associated with at least one of the following: one candidate relay device served by a second network device, a first set of candidate relay devices served by the second network device, or a second set of candidate relay devices served by a cell provided by the second network device.
  • the preparation response is a request acknowledge or a preparation failure.
  • the preparation failure indicates at least one candidate relay device with a preparation failure
  • a cause value for the preparation failure of a candidate relay device of the at least one candidate relay device is one of the following: lacking available radio resources for the candidate relay device, the candidate relay device being not available, or the candidate relay device performing a handover.
  • the processor is further configured to cause the second network device to: after receiving the preparation request, receive a first cancel message from the first network device, the first cancel message comprising: an indication used for cancelling preparation for all the candidate relay devices served by the second network device, an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell, or a set of terminal device identifiers corresponding to a set of candidate relay devices to be cancelled.
  • the processor is further configured to cause the second network device to: after transmitting the handover request acknowledge, transmit a second cancel message to the first network device, the second cancel message comprising: an indication used for cancelling preparation for all the candidate relay devices served by the second network device, an identifier of a cell used for cancelling preparation for all the candidate relay devices served by the cell, or a set of terminal device identifiers corresponding to a set of candidate relay devices to be cancelled.
  • the number of candidate relay terminal device indicated by the first or second cancel message is a multiple of a predefined number.
  • a remote terminal device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the remote terminal device discussed above.
  • a first network device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the first network device, discussed above.
  • a relay terminal device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the relay terminal device discussed above.
  • a first network device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the first network device discussed above.
  • a second network device comprises: at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the device to perform the method implemented by the second network device discussed above.
  • a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the remote terminal device discussed above.
  • a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first network device, discussed above.
  • a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the relay terminal device discussed above.
  • a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first network device discussed above.
  • a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the second network device discussed above.
  • a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the remote terminal device discussed above.
  • a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first network device, discussed above.
  • a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the relay terminal device discussed above.
  • a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first network device discussed above.
  • a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the second network device discussed above.
  • 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 which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
  • 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 those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGS. 1 to 16.
  • program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types.
  • the functionality of the program modules may be combined or split between program modules as desired in various embodiments.
  • Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.
  • Program code for carrying out 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, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented.
  • the program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
  • the above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
  • the machine readable medium may be a machine readable signal medium or a machine readable storage medium.
  • a machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.
  • machine readable storage medium More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, 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 disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
  • RAM random access memory
  • ROM read-only memory
  • EPROM or Flash memory erasable programmable read-only memory
  • CD-ROM portable compact disc read-only memory
  • magnetic storage device or any suitable combination of the foregoing.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Des exemples de modes de réalisation de la présente divulgation concernent un procédé de communication, comprenant les étapes suivantes : un dispositif terminal distant reçoit, en provenance d'un premier dispositif de réseau desservant le dispositif terminal distant, des informations de configuration de commutateur de trajet conditionnel utilisées pour commuter le dispositif terminal distant d'un premier trajet vers un second trajet, au moins l'un des premier et second trajets étant un trajet indirect et les informations de configuration de commutateur de trajet conditionnel indiquant : des premières informations indiquant au moins une première condition de commutation correspondant à au moins un premier nœud candidat comprenant une cellule candidate ou un dispositif terminal de relais candidat, les premières informations étant associées à un scénario de défaillance de trajet ; et en réponse à la détermination d'une défaillance de trajet, déterminer, à partir du ou des premiers nœuds candidats, un premier nœud candidat en tant que nœud cible si une première condition de commutation correspondante est satisfaite.
PCT/CN2023/116628 2023-09-01 2023-09-01 Procédés, dispositifs et support de communication Pending WO2025043735A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113873586A (zh) * 2020-06-30 2021-12-31 华为技术有限公司 一种通信路径切换方法、装置及系统
WO2022188855A1 (fr) * 2021-03-12 2022-09-15 维沃移动通信有限公司 Procédé et appareil de commutation de trajet, terminal et support d'enregistrement
WO2023140701A1 (fr) * 2022-01-21 2023-07-27 Samsung Electronics Co., Ltd. Procédé exécuté par un nœud de communication et nœud de communication dans un système de communication

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Publication number Priority date Publication date Assignee Title
CN113873586A (zh) * 2020-06-30 2021-12-31 华为技术有限公司 一种通信路径切换方法、装置及系统
WO2022188855A1 (fr) * 2021-03-12 2022-09-15 维沃移动通信有限公司 Procédé et appareil de commutation de trajet, terminal et support d'enregistrement
WO2023140701A1 (fr) * 2022-01-21 2023-07-27 Samsung Electronics Co., Ltd. Procédé exécuté par un nœud de communication et nœud de communication dans un système de communication

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