Mobility management methods and apparatuses, storage medium and program product

Abstract

Provided in the present disclosure are mobility management methods and apparatuses, a storage medium and a program product. A mobility management method comprises: a first node executes a first operation when a first condition is satisfied in a handover process without random access, the first operation comprising at least one of the following: reporting mobility-related information, and triggering a random access process, the first condition being a condition that causes performance degradation or handover failure of the first node, and the mobility-related information being used for indicating a cause of performance degradation or a cause of handover failure of the first node.

Description

Mobility management method and device, storage medium and program product

[0001] The present application claims priority to the Chinese patent application No. 202411092792.X, filed on August 08, 2024, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates to the field of communication technology, and in particular, to a mobility management method and device, a storage medium and a program product. BACKGROUND

[0003] In the New Radio (NR) system of the 3rd Generation Partnership Project (3GPP), a design of random access channel less (RACH-less) handover is introduced, that is, a user terminal (UE) can skip the random access procedure and directly access the target cell in the mobility process. However, in this process, the performance may be degraded, or even radio link failure (RLF) or handover failure (HOF) due to improper network configuration or other reasons.

[0004] At present, the related technology does not support the network side to identify the above-mentioned scenarios. SUMMARY

[0005] In one aspect, a mobility management method is provided, applied to a first node, the mobility management method comprising: performing, by the first node, a first operation in a case where the first node meets a first condition in a random access less handover process. The first operation comprises at least one of the following: reporting mobility related information, triggering a random access procedure. The first condition is a condition causing the first node to have performance degradation or handover failure. The mobility related information is used to indicate at least one of the following: a reason for the first node to have performance degradation, a reason for the first node to have handover failure, and related context information.

[0006] In another aspect, a mobility management method is provided, applied to a second node, the mobility management method comprising: receiving mobility related information reported by a first node. The mobility related information is reported by the first node in a case where the first node meets a first condition in a random access less handover process. The first condition is a condition causing the first node to have performance degradation or handover failure. The mobility related information is used to indicate at least one of the following: a reason for the first node to have performance degradation, a reason for the first node to have handover failure, and related context information.

[0007] In another aspect, a mobility management apparatus is provided, which is applied to a first node, and includes a processing module configured to perform a first operation if a first condition is met in a handover procedure without random access. The first operation includes at least one of the following: reporting mobility related information, triggering a random access procedure. The first condition is a condition that causes performance degradation or handover failure of the first node. The mobility related information is used to indicate at least one of the following: a reason for performance degradation of the first node, a reason for handover failure of the first node, and related context information.

[0008] In another aspect, a mobility management apparatus is provided, which is applied to a second node, and includes a communication module configured to receive mobility related information reported by a first node. The mobility related information is reported by the first node if a first condition is met in a handover procedure without random access. The first condition is a condition that causes performance degradation or handover failure of the first node. The mobility related information is used to indicate at least one of the following: a reason for performance degradation of the first node, a reason for handover failure of the first node, and related context information.

[0009] In another aspect, a communication apparatus is provided, which includes a memory and a processor. The memory is coupled to the processor. The memory is configured to store a computer program. The processor is configured to implement the mobility management method described above when executing the computer program.

[0010] In another aspect, a computer readable storage medium is provided, which stores computer program instructions. The computer program instructions are executed by a processor to implement the mobility management method described above.

[0011] In another aspect, a computer program product is provided, which includes computer program instructions. The computer program instructions are executed by a processor to implement the mobility management method described above. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the present disclosure, the following will briefly introduce the drawings needed to be used in some embodiments of the present disclosure. Obviously, the drawings described in the following are only some of the drawings of the present disclosure, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0013] FIG. 1 is a schematic diagram of an architecture of a communication system according to some embodiments of the present disclosure.

[0014] FIG. 2 is a schematic diagram of another architecture of a communication system according to some embodiments of the present disclosure.

[0015] FIG. 3 is a flowchart of a mobility management method according to some embodiments of the present disclosure.

[0016] FIG. 4 is a structural schematic diagram of a mobility management apparatus according to some embodiments of the present disclosure.

[0017] FIG. 5 is a structural schematic diagram of another mobility management apparatus according to some embodiments of the present disclosure.

[0018] FIG. 6 is a structural schematic diagram of a communication apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0019] The technical solutions in the present disclosure will be described clearly and completely below with reference to the drawings in the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0020] It should be noted that in the present disclosure, the words such as "exemplary" or "for example" are used to describe examples, illustrations, or descriptions. Any embodiment or design scheme described in the present disclosure by the words such as "exemplary" or "for example" should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the words such as "exemplary" or "for example" are intended to present the relevant concept in a specific manner.

[0021] Hereinafter, the terms "first", "second", and the like are used only for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined by "first", "second", and the like can be explicitly or implicitly included one or more of the features.

[0022] In the description of the present disclosure, unless otherwise specified, " / " means "or", for example, A / B can mean A or B. "And / or" in this document is only used to describe the association relationship of the associated objects, which means that there can be three kinds of relationships. For example, A and / or B can mean: only A, only B, and A and B. In addition, "at least one" means one or more, and "multiple" means two or more.

[0023] First, the technical terms related to the embodiments of the present disclosure are introduced.

[0024] 1. RACH-less refers to a technology used in a mobile communication network to reduce handover delay and data transmission interruption.

[0025] In traditional handover procedures, a UE needs to synchronize with and request resources from the target node via a RACH (Random Access Channel) procedure before switching to a new node (e.g., base station, cell, satellite, etc.). However, the RACH procedure can introduce additional delay and data transmission interruption. RACH-less techniques avoid these issues in several ways (pre-allocated resources, direct synchronization, reduced signaling overhead).

[0026] Pre-allocated resources: Before handover, the source node sends a handover request to the target node, indicating that the target node pre-allocate necessary UL (Uplink) resources for the UE. These resources can be used by the UE immediately after handover is completed, without waiting for the RACH procedure.

[0027] Direct synchronization: The UE can use information received from the source node (e.g., TA (Timing Advance) amount, etc.) to synchronize with the target node, thereby avoiding the synchronization step in the RACH procedure.

[0028] Reduced signaling overhead: Since the RACH procedure does not need to be performed, RACH-less techniques significantly reduce the signaling overhead in the handover procedure, further shortening the handover time.

[0029] 2. L1 / L2 Triggered Mobility (LTM) is a mobility management mechanism introduced by 3GPP in Release 18, which aims to directly trigger cell switching through physical layer (L1) or link layer (L2) signaling without waiting for RRC (Radio Resource Control) layer reconfiguration. In LTM, a PDCCH ordered RACH mechanism is introduced, i.e., before handover, the network triggers the terminal to obtain the TA of the target cell through PDCCH, and the uplink synchronization is completed in advance. In this way, after receiving the handover instruction (LTM cell switch command corresponding to MAC CE (medium access control control element)), the terminal can quickly establish a connection with the target node, thereby reducing the handover delay and interruption time.

[0030] 3. RACH based handover (HO) is a procedure in mobility management where the UE needs to re-establish uplink synchronization and connection with the target node through the RACH procedure when it needs to switch from one node to another.

[0031] 4. mobile Integrated Access and Backhaul (mIAB) is a wireless communication technology in 5G networks that combines the functions of Access Network and Backhaul Network, enabling base stations to provide both user equipment access services and backhaul transmission services.

[0032] 5. fallback, in signal processing and communication protocols, refers to the automatic use of simpler or more reliable communication methods or protocols by systems or devices under certain conditions to ensure effective transmission of information. For example, in the RACH process, if the RACH-less method fails or the conditions are not met, the system may fall back to RACH based HO.

[0033] 6. resync, in a communication system, generally refers to the process of re-establishing or restoring synchronization between the UE and the network when the synchronization state is lost or becomes unstable. In the quasi-Earth fixed scenario, satellite switching with re-synchronization in NTN is supported when using the same Synchronization Signal Block (SSB) frequency and the same gNB for hard and soft handover. Satellite switching with re-synchronization avoids L3 (Layer 3) mobility within the cell by maintaining the same PCI (Physical Cell Identifier) within the geographical area covered by the quasi-Earth fixed beam. In this process, the UE synchronizes with the target satellite at a time point or time range configured by the network. There are two mechanisms, soft satellite switch over and hard satellite switch over. For soft satellite switch over, the UE can start synchronizing with the target satellite before the source satellite ends the service cell. The UE does not need to remain connected to the source satellite when switching to the target satellite. For hard satellite switch over, the UE can only start synchronizing with the target satellite after switching to the target satellite is initiated.

[0034] The above is an introduction to the technical terms involved in the embodiments of the present disclosure, which will not be repeated below.

[0035] As in the background, the RACH-less design is introduced in the 3GPP NR system, that is, the UE can skip the random access process and directly access the target cell during mobility. RACH-less can be used in at least one of the following scenarios: LTM scenario, non-terrestrial network (Non-Terrestrial Networks, NTN) scenario, mIAB scenario, etc.

[0036] Exemplarily, the RACH-less mobility process needs to help the UE obtain the following information: whether the TA value exists or is available and the resources used by the UE after accessing the target cell.

[0037] 1. Whether the TA value exists or is available.

[0038] Exemplarily, if the network side does not configure the TA, or the UE fails to obtain the TA (for LTM, at this time the UE should not enter the RACH-less process at the beginning, so there is no fallback process), the information obtained by the UE may be that the TA does not exist.

[0039] 2. The resources used by the UE after accessing the target cell, that is, the grant (Grant) resources.

[0040] Exemplarily, the Grant can be divided into two categories: configured grant (CG) or dynamic grant (DG).

[0041] Exemplarily, the network side configures the CG resource for RACH-less, and the CG resource is configured to the UE through RRC or DG, but the CG resource needs to be used only when the preset condition is met. For example, the preset condition can include whether the reference signal received power (Reference Signal Received Power, RSRP) of the beam or SSB associated with the CG resource is greater than or equal to a preset threshold. In the case where the CG resource does not meet the preset condition, the CG resource is unavailable, and the UE can also fallback to the RACH based HO process.

[0042] However, in this process, the performance may be degraded, or even RLF or HOF due to improper network configuration or other reasons.

[0043] Currently, mobility robustness optimization (MRO) in self-organizing networks (SON) or minimization of drive tests (MDT) technology does not support the network side to identify the above scenarios.

[0044] Therefore, how to enable the network side to perceive the cause of performance degradation or failure is an urgent problem to be solved.

[0045] To solve the above technical problems, the embodiments of the present disclosure provide a mobility management method, and the idea is that a first node performs a first operation when a first condition is met in a handover process without random access. The first operation includes at least one of the following: reporting mobility related information and triggering a random access process. The first condition is a condition that causes performance degradation or handover failure of the first node. The mobility related information is used to indicate the cause of performance degradation or the cause of handover failure of the first node.

[0046] It can be understood that the embodiments of the present disclosure can enable the first node to report mobility related information and / or trigger a random access process when performance degradation or handover failure occurs in the handover process without random access. In this way, the second node can perceive the performance degradation or handover failure of the first node, and then analyze the cause of the performance degradation or handover failure of the first node. At the same time, by triggering the random access process, the waiting time and the delay of the first node can be reduced.

[0047] To facilitate understanding of the embodiments of the present disclosure, first, a communication system applicable to the embodiments of the present disclosure is described in detail with reference to the communication system shown in FIG. 1. Exemplarily, FIG. 1 is a schematic diagram of the architecture of a communication system to which the mobility management method according to the embodiments of the present disclosure is applicable. As shown in FIG. 1, the communication system includes a terminal device and a network device.

[0048] The terminal device is a terminal device with a wireless transceiver function for accessing the communication system or a chip or chip system that can be provided in the terminal device. The terminal device can also be referred to as a user equipment, an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user device. The terminal in the embodiments of the present disclosure can be a mobile phone, a tablet computer, a computer with a wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a vehicle-mounted terminal, an RSU with terminal function, a physical network terminal, etc. The terminal device of the present disclosure can also be a vehicle-mounted module, a vehicle-mounted module, a vehicle-mounted component, a vehicle-mounted chip, or a vehicle-mounted unit built into a vehicle as one or more components or units. The vehicle can implement the mobility management method provided by the present disclosure through the built-in vehicle-mounted module, vehicle-mounted module, vehicle-mounted component, vehicle-mounted chip, or vehicle-mounted unit.

[0049] The network device is located at a network side of the communication system and is a device with wireless transceiving function or a chip or chip system that can be arranged in the device. The network device includes but is not limited to: a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, a home evolved node B or a home node B, HNB), a baseband unit (BBU), a wireless relay node, a wireless backhaul node, a transmission and reception point (TRP) or a transmission point (TP), etc., and can also be a gNB in a 5G system such as a new radio (NR) system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or a network node constituting a gNB or a transmission point, for example, a baseband unit (BBU), or a distributed unit (DU), a road side unit (RSU) with a base station function, etc.

[0050] Exemplarily, the communication system can be applied to a new radio (NR) terrestrial network (TN). The terminal device in the communication system can be a first node, and the network device can be a second node.

[0051] In some other embodiments, the communication system can further include a flight platform. As shown in FIG. 2, the communication system can include a network device, a terminal device, and a flight platform.

[0052] The network device is an access network device arranged on the ground. The terminal device and the access network device can communicate by forwarding signals through the flight platform. For example, the flight platform and the access network device can communicate through a next generation (NG) interface. The communication link between the flight platform and the access network device can be referred to as a feeder link. The flight platform can provide a transmission / reception point (TRP) for the terminal device to access wirelessly. The TRP can transparently transmit data between the terminal device and the access network device, thereby realizing the communication connection between the terminal device and the access network device. At this time, the flight platform can be described as working in a transparent mode. It should be noted that the access network device can also be described as a gateway station, a ground station, etc., without limitation.

[0053] In some embodiments, the access network device can be carried on the flight platform. When the access network device is carried on the flight platform, the access network device moves synchronously with the flight platform, and the access network device and the flight platform can be regarded as a whole. At this time, the flight platform can be regarded as the access network device, and the flight platform can also be described as working in a regenerative mode, i.e., the flight platform has the function of the access network device. In addition, the communication link between the flight platform and the terminal device can be referred to as a service link.

[0054] It should be noted that the flight platform can be a satellite, a drone, or other aircraft. For example, the flight platform can include a geostationary satellite, a non-geostationary satellite, a low earth orbit satellite, a medium earth orbit satellite, a geosynchronous earth orbit satellite, an unmanned aerial system platform, or a high earth orbit satellite, without limitation.

[0055] Alternatively, the access network device can be distributed on the flight platform based on a distributed unit (DU). When the access network device is distributed on the flight platform based on the DU, the flight platform can be regarded as part of the access network device, and the flight platform can also be described as working in a regenerative mode, i.e., the flight platform has the function of part of the access network device.

[0056] For example, the above communication system can be applied to an NTN of NR. The terminal device in the communication system can be a first node, and the network device or the flight platform can be a second node.

[0057] It should be noted that the methods in the following embodiments can be implemented in the above communication system. The schemes in the embodiments of the present disclosure can also be applied to other communication systems, and the corresponding names can be replaced by the names of corresponding functions in other communication systems.

[0058] After introducing the application scenario and implementation environment of the embodiments of the present disclosure, the mobility management method provided by the embodiments of the present disclosure will be described in detail in combination with the above implementation environment.

[0059] As shown in FIG. 3, the present disclosure provides a mobility management method applied to a communication system as shown in FIG. 1 or FIG. 2, the mobility management method comprising the following S201.

[0060] In S201, the first node performs a first operation in a case where a first condition is met in a handover procedure without random access.

[0061] The first condition is a condition leading to performance degradation or handover failure of the first node.

[0062] In some embodiments, the first operation comprises at least one of the following: reporting mobility-related information, triggering a random access procedure.

[0063] The mobility-related information is used to indicate at least one of the following: a reason for performance degradation of the first node, a reason for handover failure of the first node, and related context information.

[0064] The above-mentioned related context information is context information related to handover, or context information related to mobility.

[0065] In some embodiments, the mobility-related information is carried in at least one of the following reports: a radio link failure (RLF) report, a RACH report, and a successful handover report (SHR).

[0066] In some embodiments, the above-mentioned handover procedure without random access further comprises an NTN resynchronization procedure. For example, the description of the NTN resynchronization procedure is described below and will not be repeated here.

[0067] In some embodiments, in a case where the first operation comprises reporting mobility-related information, the second node receives the mobility-related information reported by the first node.

[0068] In some embodiments, the first condition comprises at least one of the following: the first node is configured with CG resources but switches to the target cell based on DG resources; the first node experiences handover failure or RLF within a first preset time period after successful handover, i.e., the first node experiences RLF soon after successful handover; a first timer in the first scenario expires, the first timer being used to maintain uplink time synchronization; the first node falls back from a handover procedure without random access to a handover procedure with random access; the first node experiences link failure in the process of NTN resynchronization; the number of resynchronizations in the process of NTN resynchronization is greater than a threshold of the number of resynchronizations; or the time of resynchronization in the process of NTN resynchronization is greater than a threshold of the time of resynchronization.

[0069] The first scenario comprises at least one of the following: LTM, handover procedure without random access (i.e., RACH-less), or NTN resynchronization.

[0070] Exemplarily, the first timer can be a time alignment timer (TAT).

[0071] In the following, different cases in the first condition are described respectively.

[0072] In some embodiments, in the case where the first condition comprises: the first node is configured with CG resources but switches to the target cell based on DG resources; and / or the first node experiences handover failure or RLF within a first preset time period after successful handover, the first operation comprises: reporting mobility-related information.

[0073] The mobility-related information comprises at least one of the following: CG resources configured by the second node; cell and beam information corresponding to the CG resources; information of the target cell and the target beam configured by the first node in the LTM process; and type of resources used by the first node.

[0074] It can be understood that, in the process of LTM, the first node switches to the target cell based on DG resources, which results in that the configured CG resources are not well utilized, and using DG resources can result in higher access latency, causing the first node to experience performance degradation. In this regard, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the mobility-related information to the second node. In this way, the second node can perceive that the first node experiences performance degradation and analyze the reason why the first node experiences performance degradation.

[0075] In some embodiments, in the case where the first condition comprises: the first timer in the first scenario expires, the first operation comprises: reporting mobility-related information and / or triggering a random access procedure.

[0076] The mobility-related information includes at least one of the following: indication information of the first timer expiring; configuration of the first timer; configuration of the second timer; time for which the second timer is used to control the handover procedure; configuration of the T304 timer; and cause for which the first node initiates the RACH procedure.

[0077] It can be understood that the first timer expiring in the first scenario causes the first node to have service interruption and bear unnecessary latency. The access latency is increased, and the first node has performance degradation or access failure. In this regard, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the above-mentioned mobility-related information to the second node. In this way, the second node can perceive that the first node has performance degradation or access failure, and analyze the cause of the performance degradation or access failure of the first node.

[0078] In some embodiments, the first condition includes a case where the first node falls back from the RACH-less handover procedure to the RACH handover procedure. The first operation includes reporting the mobility-related information.

[0079] The mobility-related information includes at least one of the following: event of the first node falling back from the RACH-less procedure to the RACH handover procedure; cause of the first node falling back from the RACH-less procedure to the RACH handover procedure; CG resource list configured by the first node; information of a beam corresponding to the CG resource configured by the first node; measurement value of the beam corresponding to the CG resource configured by the first node; beam quality threshold value configured by the second node for the fallback event; measurement value of the selected beam by the first node; configuration information of the RACH-less procedure; and application scenario of the RACH-less.

[0080] Exemplarily, the configuration information of the RACH-less procedure includes at least one of the following: timing advance, beam configuration information, and CG configuration information.

[0081] Exemplarily, the application scenario of the RACH-less includes at least one of the following: NTN and mIAB.

[0082] It can be understood that, in the fallback procedure, the RACH based HO procedure introduces additional access latency, thereby increasing the service interruption time and causing the first node to have performance degradation or access failure. In this regard, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the above-mentioned mobility-related information to the second node. In this way, the second node can perceive that the first node has performance degradation or access failure, and analyze the cause of the performance degradation or access failure of the first node.

[0083] In some embodiments, in a case where the first condition comprises: the first node link failure in a process of NTN resynchronization, the first operation comprises: reporting mobility related information.

[0084] The mobility related information comprises at least one of: position and velocity vector information of the satellite; orbit information of the satellite; reference time; time when the source satellite stops serving; time when the target satellite starts serving; time when a third timer is configured, the third timer being used to control time of the resynchronization process; time when a T430 timer is configured; parameters used to assist the first node to perform resynchronization in a non-terrestrial network scenario; measurement value of the first node on the source beam and the target beam; service interruption time, the service interruption time being used to represent time of service interruption caused by resynchronization of the NTN scenario.

[0085] It can be understood that, in the NTN resynchronization process, if the resynchronization time is too long, it can cause the first node to generate link failure, and then trigger the UE to perform re-access and RRC reconstruction, and the like, so that the first node has performance decline or access failure. In this regard, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the above-mentioned mobility related information to the second node. In this way, the second node can perceive that the first node has performance decline or access failure, and analyze the reason why the first node has performance decline or access failure.

[0086] In some embodiments, in a case where the first condition comprises: the number of resynchronizations in the process of NTN resynchronization is greater than a resynchronization number threshold; and / or, the time of resynchronization in the process of NTN resynchronization is greater than a resynchronization time threshold, the first operation comprises: reporting mobility related information.

[0087] The mobility related information comprises at least one of: an event that the number of resynchronizations is greater than the resynchronization number threshold; an event that the time of resynchronization is greater than the resynchronization time threshold; the resynchronization number threshold configured by the second node; the resynchronization time threshold configured by the second node; the number of resynchronizations actually performed by the first node; the time of resynchronization actually performed by the first node.

[0088] It can be understood that, in the NTN resynchronization process, the first node may have a link failure due to a too long resynchronization time, thereby triggering the UE to perform re-access and RRC reconstruction, and the like, causing the first node to have performance degradation. Therefore, the first node needs to assist the network in identifying the problem. In this regard, the embodiment of the present disclosure introduces a SHR enhancement mode, wherein the first node reports the above mobility-related information to the second node in the case that the number of times of resynchronization in the NTN resynchronization process is greater than a resynchronization number threshold; and / or, the time of resynchronization in the NTN resynchronization process is greater than a resynchronization time threshold. In this way, the second node can perceive that the first node has performance degradation, and analyze the cause of the performance degradation of the first node.

[0089] For ease of understanding, the mobility management method provided by the embodiment of the present disclosure is described below by taking different five scenarios as examples.

[0090] Scenario one: in the RACH-less LTM scenario, the first node selects a DG resource.

[0091] Exemplarily, the implementation process of RACH-less LTM can include the following: Sa1 to Sa3.

[0092] In Sa1, after obtaining a valid TA value, the first node enters the ongoing RACH-less L1 / L2 layer triggered mobility (LTM) process.

[0093] Exemplarily, the above valid TA value can be configured by the network or detected by the first node, which is not limited by the embodiment of the present disclosure.

[0094] In Sa2, the first node determines whether the network has configured an associated CG for the beam according to the beam indicated by the LTM cell switch command. If there is a valid CG resource for the beam, the first node selects the CG resource corresponding to the beam as the resource used for accessing the target cell.

[0095] In Sa3, in the case that the first node does not find a valid CG resource, the first node schedules a DG resource as the resource for accessing the target cell.

[0096] According to the above procedure, the following situation can exist: the second node configures multiple beams (carried in the LTM candidate list) for the first node in the RRC (Radio Resource Control) signaling before the LTM cell switch command. Some beams are configured with CG resources, and some beams are not configured with CG resources, and the second node finally selects a beam without CG resources as the target beam, which can cause the configured CG resources not to be well utilized, and the UE can select to schedule DG resources as the resource for accessing the target cell because there is no CG resource on the target beam, which can cause a higher access delay.

[0097] For example, it is assumed that among the beams 1, 2 and 3, the beams 1 and 2 are configured with CG resources, but the second node finally selects the beam 3 as the target beam of the LTM cell switch, at this time the configured CG resources are not well utilized, and the first node also uses the DG resource because there is no CG resource on the beam 3, which can cause a higher access delay.

[0098] It can be seen that in scenario one, there is a technical problem of low CG resource utilization and increased access delay, which causes the first node to have LTM performance degradation.

[0099] To this end, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the cause of the performance degradation of the first node or related context information to the second node. In this way, the second node can perceive the performance degradation of the first node and analyze the cause of the performance degradation of the first node.

[0100] For example, in scenario one, the mobility management method provided by the embodiments of the present disclosure can include: the first node is configured with CG resources but switches to the target cell based on the DG resource; and / or the first node reports mobility-related information to the second node in the case of switching failure or RLF within a first preset time period after switching success.

[0101] The mobility-related information can include one or more of the following: CG resources configured by the second node; cell and beam information corresponding to the CG resources; information of the target cell and the target beam configured for the first node in the LTM process; and the type of resource used by the first node.

[0102] For example, the type of resource used by the first node can be CG resources or DG resources.

[0103] In some embodiments, the mobility related information can be carried in the RLF report or the SHR. For example, if the above procedure times out and causes HOF, the first node updates the RLF report.

[0104] Scenario two: the first timer times out in the first scenario.

[0105] The first timer is used to maintain uplink time synchronization. For example, the first timer can be TAT.

[0106] For example, the first scenario includes at least one of the following: LTM, handover procedure without random access, NTN resynchronization, mIAB.

[0107] In some embodiments, in the first scenario, the first node starts the TAT for the valid TA configured or provided by the second node after receiving the cell switch command or starting the handover procedure without random access. However, in some network configurations, the TAT in the first scenario can time out. That is, the mobility procedure has not been completed, but the TAT has timed out.

[0108] After the TAT times out, the first node cannot send any uplink data and can only wait for the second timer (the second timer is used to control the time of the handover procedure, for example, the second timer can be timer T304) to time out and perform the reestablishment or LTM recovery procedure through the RACH. Therefore, the first node bears unnecessary waiting time and service interruption during this process, resulting in a high mobility procedure delay.

[0109] As can be seen, in scenario two, the first node service is interrupted due to the timer TAT timing out, and bears unnecessary waiting time, the mobility procedure delay increases, and the first node performance degrades or access fails.

[0110] To this end, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the cause of the performance degradation of the first node, the cause of the access failure or related context information to the second node. In this way, the second node can perceive the performance degradation or access failure of the first node and analyze the cause of the performance degradation or access failure of the first node.

[0111] In some embodiments, in scenario two, the mobility management method provided by the embodiments of the present disclosure can include: in the case where the first timer times out in the first scenario, the first node reports mobility related information to the second node.

[0112] The mobility-related information includes at least one of the following: indication information of the first timer expiring; configuration of the first timer; configuration of the second timer; time for which the second timer is used to control the handover procedure; configuration of the T304 timer; and cause for which the first node initiates the RACH procedure is the first timer expiring.

[0113] As an implementation manner, the mobility-related information can be carried in an RLF report. For example, if the T304 timer expires, the first node performs RRC reestablishment and generates a corresponding RLF report.

[0114] As another implementation manner, the mobility-related information can be carried in a RACH report. For example, if the T304 timer expires, the first node performs RACH-based cell access, so there is a RACH procedure, and therefore the first node can carry the mobility-related information in the RACH report.

[0115] In some embodiments, in scenario two, the mobility management method provided by the embodiments of the present disclosure can further include: in the case where the first timer in the first scenario expires, the first node triggers a random access procedure.

[0116] It can be understood that the embodiments of the present disclosure can also introduce a corresponding enhancement, that is, in the case where the timer TAT in the first scenario expires, the RACH procedure is directly triggered. For example, the first node exits from the LTM or the mobility procedure without random access, directly enters the RRC reestablishment process, and triggers the RACH procedure.

[0117] In some embodiments, in scenario two, the mobility management method provided by the embodiments of the present disclosure can further include: in the case where the first timer in the first scenario expires, the first node reports mobility-related information and triggers a random access procedure.

[0118] It can be understood that in the case where the timer TAT in the first scenario expires, in addition to simply allowing the network side to perceive the cause of the performance degradation or access failure of the first node, the embodiments of the present disclosure can also trigger the RACH procedure. In this way, unnecessary waiting time of the first node can be reduced, and latency can be reduced.

[0119] Scenario three, the first node falls back from a handover procedure without random access to a handover procedure with random access.

[0120] Exemplarily, the fallback of the first node from a handover procedure without random access (for example, in a non-LTM scenario, that is, an NTN and / or mIAB scenario) to a handover procedure with random access, that is, the fallback of the access mode, can include the following: Sc1 to Sc2.

[0121] In Sc1, after the mobility without random access is triggered, the first node checks whether there are CG resources meeting the condition (i.e., whether the beam quality associated with the CG resource is higher than the configured beam quality threshold), and if there are CG resources meeting the condition, selects a suitable beam from the corresponding beams of the CG resources meeting the condition, and starts the transmission of service data.

[0122] In Sc2, if the first node is not configured with CG resources, the first node operates based on the DG resources possibly indicated by the second node, i.e., the first node performs PDCCH monitoring according to the beam information indicated by the second node.

[0123] For the handover procedure without random access in the non-LTM scenario, if the second node configures the first node with CG resources, the first node directly skips the DG behavior. The first node starts to check from whether the CG is configured: if the first node is configured with CG resources, it will determine whether there are available CG resources when selecting CG resources, and if there are no available CG resources meeting the condition (i.e., whether the beam quality associated with the CG resource is higher than the configured beam quality threshold), the first node falls back to the RACH based HO procedure; if the second node configures the first node with DG (i.e., the beam corresponding to the DG), the first node starts to perform PDCCH monitoring based on the DG.

[0124] When determining whether the CG resource is available, the first node can determine based on the beam quality corresponding to the CG resource. For example, the first node determines whether the measurement value of the beam corresponding to the CG resource (e.g., the beam can be an SSB beam, and the beam measurement value can be an SSB measurement value) is greater than or equal to the beam quality threshold (which can be pre-configured by the network side), and if the measurement value of the beam corresponding to the CG resource is less than the beam quality threshold, the first node falls back to the RACH based HO procedure. For example, the measurement value of the beam can be an RSRP value, and the beam quality threshold can be an RSRP threshold.

[0125] It can be understood that in the fallback process, the RACH based HO procedure introduces additional access delay, thereby increasing the service interruption time, resulting in performance degradation or access failure of the first node.

[0126] To this end, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the cause of performance degradation, the cause of access failure or related context information of the first node to the second node. In this way, the second node can perceive the performance degradation or access failure of the first node, and analyze the cause of the performance degradation or access failure of the first node.

[0127] In some embodiments, in scenario three, the mobility management method provided by the embodiments of the present disclosure can comprise: in the case that the first node falls back from the RACH-less handover process to the RACH handover process, the first node reports the mobility related information to the second node.

[0128] The mobility related information comprises at least one of the following: the event that the first node falls back from the RACH-less process to the RACH handover process; the reason that the first node falls back from the RACH-less process to the RACH handover process; the CG resource list configured by the first node; the information of the beam corresponding to the CG resource configured by the first node, for example, SSB beam; the measurement value of the beam corresponding to the CG resource configured by the first node, for example, RSRP value; the beam quality threshold value configured by the second node for the fallback event, for example, RSRP threshold value; the measurement value of the selected beam by the first node; the configuration information of the RACH-less process; the application scenario of the RACH-less.

[0129] Exemplarily, the configuration information of the RACH-less process comprises at least one of the following: timing advance, beam configuration information, CG configuration information.

[0130] Exemplarily, the application scenario of the RACH-less comprises at least one of the following: NTN, mIAB.

[0131] As an implementation manner, the information can be carried in the RLF report. For example, if the above-mentioned RACH handover process fails, i.e. HOF, the first node will perform RRC reestablishment and generate the corresponding RLF report.

[0132] As another implementation manner, the above-mentioned mobility related information can be carried in the RACH report. Meanwhile, the above-mentioned mobility related information can comprise the reason (RACH cause) that the first node falls back from the RACH-less process to the RACH handover process.

[0133] As another implementation manner, the above-mentioned mobility related information can be carried in the SHR. Exemplarily, the above-mentioned event (i.e. the event that the first node falls back from the RACH-less process to the RACH handover process) can also be the triggering event of the SHR. Once the condition is met (the first node configures the CG resource, but does not meet the condition, so that the first node falls back from the RACH-less process to the RACH based HO process), the first node generates the SHR report comprising the above-mentioned mobility related information and uploads it to the second node.

[0134] Scenario four, the first node link failure in the process of NTN resynchronization.

[0135] In NTN scenarios, there is a deployment mode called Quasi-Earth-fixed. In this deployment mode, a geographical area is covered by one beam for a period of time and is covered by another beam after a certain time point. The first node needs to synchronize with the configured target beam at a given time point or time region without involving RRC reconfiguration or even reestablishment procedure.

[0136] Exemplarily, the NTN resynchronization procedure can include the following: Sd1 to Sd5.

[0137] In Sd1, the first node receives a 19th system information block (SIB19) in a source satellite (referred to as SAT-1).

[0138] The SIB19 includes information required for RACH-less satellite handover to a target satellite, for example, the SIB19 can include at least one of the following information: NTN configuration of the target satellite, SSB index, SSB time offset.

[0139] In Sd2, the first node determines the time point of performing resynchronization (i.e., T-switch, decides the satellite switching time) at the RRC layer, and then notifies the Medium Access Control (MAC) layer. Accordingly, the MAC layer clears the Hybrid Automatic Repeat reQuest (HARQ) buffer and stops uplink transmission after receiving the time point of performing resynchronization, in preparation for switching.

[0140] Exemplarily, the RACH-less satellite handover includes hard handover or soft handover. Hard handover means that the first node needs to disconnect the connection with the source node first and then establish the connection with the target node during the switching process. For soft satellite handover, the first node can start to synchronize with the target satellite before the source satellite ends the service cell. When the first node switches to the target satellite, the first node does not need to remain connected to the source satellite.

[0141] Exemplarily, the first node can determine whether to perform soft handover based on the capability and whether the corresponding variable is configured.

[0142] For hard switch, the time point T-switch to perform re-synchronization corresponds to the time when the source satellite stops service (re-synchronize to the target satellite and start data transmission and reception); for soft switch, the first node acquires the downlink synchronization of the target satellite in the time period between [t-ServiceStart, t-Service], i.e., [the time when the target satellite starts service, the time when the source satellite stops service].

[0143] In some embodiments, once it is determined to start the switch, i.e., the third timer expires, until the switch to the target satellite. The third timer is used to control the time of re-synchronization. Exemplarily, the third timer can be timer T430.

[0144] In some embodiments, after the first node determines the time point (i.e., T-switch) to perform re-synchronization at the RRC layer, it notifies the MAC layer, and the MAC layer performs the switch.

[0145] Exemplarily, after the MAC layer receives the satellite switch start indication from the upper layer, it clears the HARQ buffer and suspends the uplink transmission (corresponding to the operation when the timer T430 expires). The first node performs subsequent downlink synchronization based on the provided SSB time offset (whether to reuse the SSB measurement timing configuration (SMTC) or use a new information element to be determined).

[0146] In Sd3, the first node starts to detect the downlink synchronization of the target satellite and performs SMTC adjustment (in the case of configuring the SSB time offset, the SSB time offset also needs to be considered).

[0147] Exemplarily, the first node detects the SSB of the target satellite, i.e., the first node detects the SSB of the target satellite in the adjusted SMTC window. If the second node does not provide the SSB information of the target satellite in the SIB19, the SSB of the source satellite is used.

[0148] In Sd4, after the first node acquires the downlink synchronization of the target satellite, it starts the timer T430 at t-Service, determines the completion of the uplink synchronization, determines the validity of the configuration on the target side, and resumes the uplink transmission.

[0149] Exemplarily, the behavior of the first node at the MAC layer includes at least one of the following: clearing the local network timing advance (NTA) value, clearing the Koffset dedicated to the first node, and allowing the uplink transmission.

[0150] Exemplarily, after the first node completes the downlink synchronization with the target satellite, it acquires SIB19, and considers that the uplink synchronization with the target satellite is completed. If the first node supports Timing Advance Reporting (TAR), it triggers TAR and Scheduling Request (SR) on TAR (TAR-SR).

[0151] In Sd5, the first node starts the uplink transmission, and transmits the TA report as the first uplink transmission.

[0152] Exemplarily, at the MAC layer, if the TAT is running, the first node transmits the TA through the uplink Physical Uplink Shared Channel (PUSCH) or triggers the Scheduling Request (SR) on the Physical Uplink Control Channel (PUCCH). If the timer TAT expires, the first node starts the uplink transmission through the RACH.

[0153] In the above scenario four, ideally (i.e. the parameters configured by the network are completely accurate, and the first node is at the corresponding time point, such as t-ServiceStart, t-Service), the first node can successfully complete the resync with the target satellite. However, in actual deployment, there are errors in the calculation of the orbit of the satellite (because the orbit of the satellite may be offset as it runs), and the handover of the coverage interval may not be ideal, which leads to the first node in the resync process may occur service interruption time too long, RLF, the first node needs to re-access the network, RRC re-establishment, etc. This requires the first node to be able to assist the network to identify the problem.

[0154] It can be understood that the events or reasons leading to service interruption can be recorded. For example, based on the spec impacts of the communication protocol, the first node can record the time interval from t-service to the uplink recovery, to help the network side to evaluate.

[0155] As can be seen, in scenario four, the resync time is too long, which may cause the first node to generate a link failure, and then trigger the UE to re-access and RRC re-establishment, etc., so that the first node has performance degradation or access failure.

[0156] To this end, the embodiments of the present disclosure enhance the related MRO mechanism, so that the first node can report the cause of performance degradation, the cause of access failure or related context information to the second node. In this way, the second node can perceive the performance degradation or access failure of the first node, and analyze the cause of the performance degradation or access failure of the first node.

[0157] In some embodiments, in scenario four, the mobility management method provided by the embodiments of the present disclosure can include: in the case of link failure of the first node in the process of NTN resynchronization, the first node reports mobility-related information to the second node.

[0158] The mobility-related information includes at least one of the following: position and velocity vector information of the satellite; orbit information of the satellite; reference time; time when the source satellite stops serving; time when the target satellite starts serving; time when the third timer is configured, the third timer being used to control the time of the resynchronization process; time when the T430 timer is configured; parameters used to assist the first node to resynchronize in the scenario of non-terrestrial network; measurement value of the first node to the source beam and the target beam; service interruption time, the service interruption time being used to represent the time of service interruption caused by resynchronization of the NTN scenario.

[0159] Exemplarily, the service interruption time can be the interval from t-Service to the recovery of the uplink of the first node.

[0160] In some embodiments, the mobility-related information can be carried in the RLF report or the RACH report. For example, if the resynchronization time is too long in scenario four, it may cause the first node to generate link failure, and then trigger the first node to perform re-access and RRC reconstruction, and then the first node will generate the corresponding RLF report or RACH report, and the mobility-related information can be carried in the RLF report or RACH report.

[0161] In the above embodiments (for scenarios one to four), for the RACH-less mobility process, even if there is no actual random access process, the corresponding RACH report will also be generated.

[0162] Scenario five, the number of resynchronizations in the process of NTN resynchronization is greater than the resynchronization number threshold; and / or, the time of resynchronization in the process of NTN resynchronization is greater than the resynchronization time threshold.

[0163] In the NTN resynchronization process (see scenario four above for the NTN resynchronization process, which will not be described again here), the first node may have a link failure due to a too long resynchronization time, triggering the UE to re-access and RRC re-establishment, and other situations, causing the performance of the first node to decline. Therefore, the first node needs to assist the network in identifying the problem.

[0164] For example, the first node can report to the second node the cause of the performance decline of the first node, the cause of the access failure, or related context information. In this way, the second node can perceive the performance decline or access failure of the first node and analyze the cause of the performance decline or access failure of the first node.

[0165] To this end, the embodiments of the present disclosure introduce a SHR enhancement mode, in which the second node can configure the first node with at least one of the following information: a resynchronization frequency threshold and a resynchronization time threshold. Further, the first node reports mobility-related information to the second node when the number of resynchronizations in the NTN resynchronization process is greater than the resynchronization frequency threshold and / or the time of resynchronization in the NTN resynchronization process is greater than the resynchronization time threshold.

[0166] The mobility-related information includes at least one of the following: an event in which the number of resynchronizations is greater than the resynchronization frequency threshold; an event in which the time of resynchronization is greater than the resynchronization time threshold; the resynchronization frequency threshold configured by the second node; the resynchronization time threshold configured by the second node; the actual number of resynchronizations performed by the first node; the actual time of resynchronization performed by the first node; position and velocity vector information of the satellite; orbital information of the satellite; reference time; time when the source satellite stops serving; time when the target satellite starts serving; time configured by a third timer for controlling the time of the resynchronization process; time configured by a T430 timer; parameters for assisting the first node to perform resynchronization in a non-terrestrial network scenario; measurement values of the first node for the source beam and the target beam; service interruption time, which is used to represent the time of service interruption caused by the NTN scenario resynchronization.

[0167] Exemplarily, the NTN resynchronization process described above can be the process from the first node attempting resynchronization to the target satellite to the successful resynchronization.

[0168] It can be understood that, in order to implement the above functions, the mobility management device comprises at least one of a hardware structure and a software module for executing respective functions. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of the examples described in the embodiments disclosed herein, the embodiments of the present disclosure can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is implemented in hardware or computer software driven hardware depends on a specific application and design constraint condition of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present disclosure.

[0169] The embodiments of the present disclosure can divide the mobility management device into functional modules according to the above method embodiments. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one functional module. The integrated module can be implemented in the form of hardware or software. It should be noted that the division of modules in the embodiments of the present disclosure is illustrative, and is only a logical functional division. When actually implemented, another division method can be used. The following will be described taking the example of dividing each functional module according to each function.

[0170] FIG. 4 is a structural schematic diagram of a mobility management device according to an embodiment of the present disclosure. The mobility management device is applied to a first node and can execute the mobility management method provided by the above method embodiments. As shown in FIG. 4, the mobility management device 600 comprises a processing module 601.

[0171] The processing module 601 is configured to, in a case where the first node meets a first condition in a handover process without random access, perform a first operation. The first operation comprises at least one of the following: reporting mobility-related information, triggering a random access process. The first condition is a condition causing performance degradation or handover failure of the first node. The mobility-related information is used to indicate at least one of the following: a reason for performance degradation of the first node, a reason for handover failure of the first node, and related context information.

[0172] In some embodiments, the first condition comprises at least one of: the first node is configured with CG resource but switches to the target cell based on DG resource; the first node has handover failure or RLF within a first preset time period after handover success; a first timer in the first scenario expires, the first timer being used for maintaining uplink time synchronization; the first node falls back from a handover procedure without random access to a handover procedure with random access; the first node has link failure in a process of NTN resynchronization; a number of times of resynchronization in the process of NTN resynchronization is greater than a threshold of number of times of resynchronization; a time of resynchronization in the process of NTN resynchronization is greater than a threshold of time of resynchronization.

[0173] In some embodiments, the first scenario comprises at least one of: LTM, a handover procedure without random access, NTN resynchronization.

[0174] In some embodiments, in a case where the first condition comprises: the first node is configured with CG resource but switches to the target cell based on DG resource; and / or, the first node has handover failure or RLF within a first preset time period after handover success, the first operation comprises: reporting mobility related information.

[0175] In some embodiments, the mobility related information comprises at least one of: CG resource configured by the second node; cell and beam information corresponding to the CG resource; information of target cell and target beam configured by the first node in the LTM procedure; type of resource used by the first node.

[0176] In some embodiments, in a case where the first condition comprises: a first timer in the first scenario expires, the first operation comprises: reporting mobility related information and / or triggering a random access procedure.

[0177] In some embodiments, the mobility related information comprises at least one of: indication information of the first timer expiring; configuration of the first timer; configuration of a second timer, the second timer being used for controlling time of a handover procedure; configuration of a T304 timer; a reason for the first node initiating a RACH procedure is the first timer expiring.

[0178] In some embodiments, in a case where the first condition comprises: the first node falls back from a handover procedure without random access to a handover procedure with random access, the first operation comprises: reporting mobility related information.

[0179] In some embodiments, the mobility related information comprises at least one of: an event that the first node falls back from the RACH-less procedure to the RACH switching procedure; a cause that the first node falls back from the RACH-less procedure to the RACH switching procedure; a list of CG resources configured by the first node; information of beams corresponding to the CG resources configured by the first node; measurement values of the beams corresponding to the CG resources configured by the first node; a beam quality threshold configured by the second node for the falling back event; a measurement value of a selected beam by the first node; configuration information of the RACH-less procedure; an application scenario of the RACH-less.

[0180] In some embodiments, the configuration information comprises at least one of: a timing advance, beam configuration information, CG configuration information.

[0181] In some embodiments, the application scenario comprises at least one of: NTN, mIAB.

[0182] In some embodiments, the first operation comprises reporting the mobility related information in a case that the first condition comprises: a case that the first node fails in a procedure of NTN resynchronization.

[0183] In some embodiments, the mobility related information comprises at least one of: position and velocity vector information of a satellite; orbit information of the satellite; a reference time; a time when a source satellite stops serving; a time when a target satellite starts serving; a time when a third timer configured to control a time of a resynchronization procedure; a time when a T430 timer is configured; a parameter used to assist the first node to perform resynchronization in a scenario of non-terrestrial network; a measurement value of a source beam and a target beam by the first node; a service interruption time used to represent a time of service interruption due to resynchronization of NTN scenario.

[0184] In some embodiments, the first operation comprises reporting the mobility related information in a case that the first condition comprises: a case that a number of resynchronizations in a procedure of NTN resynchronization is greater than a resynchronization number threshold; and / or, a case that a time of resynchronization in the procedure of NTN resynchronization is greater than a resynchronization time threshold.

[0185] In some embodiments, the mobility related information comprises at least one of: an event that the number of resynchronizations is greater than the resynchronization number threshold; an event that the time of resynchronization is greater than the resynchronization time threshold; a resynchronization number threshold configured by the second node; a resynchronization time threshold configured by the second node; a number of resynchronizations actually performed by the first node; a time of resynchronization actually performed by the first node.

[0186] In some embodiments, the mobility related information is carried in at least one of the following reports: RLF report, RACH report, SHR.

[0187] FIG. 5 is a structural schematic diagram of another mobility management apparatus according to an embodiment of the present disclosure, which is applied to a second node and can perform the mobility management method provided by the method embodiments described above. As shown in FIG. 5, the mobility management apparatus 700 includes a communication module 701.

[0188] The communication module 701 is configured to receive mobility-related information reported by the first node. The mobility-related information is reported by the first node in a case where the first node meets a first condition in a handover process without random access. The first condition is a condition that causes performance degradation or handover failure of the first node. The mobility-related information is used to indicate at least one of the following: a reason for performance degradation of the first node, a reason for handover failure of the first node, and related context information.

[0189] In some embodiments, the first condition includes at least one of the following: the first node is configured with CG resources but switches to a target cell based on DG resources; the first node experiences handover failure or RLF within a first preset time period after successful handover; a first timer in the first scenario times out, the first timer being used to maintain uplink time synchronization; the first node falls back from the handover process without random access to the handover process with random access; the first node experiences link failure in the process of NTN resynchronization; the number of resynchronizations in the process of NTN resynchronization is greater than a resynchronization number threshold; and the time of resynchronization in the process of NTN resynchronization is greater than a resynchronization time threshold.

[0190] In some embodiments, the first scenario includes at least one of the following: LTM, handover process without random access, and NTN resynchronization.

[0191] In some embodiments, in a case where the first condition includes: the first node is configured with CG resources but switches to a target cell based on DG resources; and / or the first node experiences handover failure or RLF within a first preset time period after successful handover, the mobility-related information includes at least one of the following: CG resources configured by the second node; cell and beam information corresponding to the CG resources; information of a target cell and a target beam configured for the first node in the LTM process; and a type of resources used by the first node.

[0192] In some embodiments, in a case where the first condition includes: the first timer in the first scenario times out, the mobility-related information includes at least one of the following: indication information of the first timer timing out; configuration of the first timer; configuration of a second timer; the second timer being used to control the time of the handover process; configuration of a T304 timer; and a reason for the first node initiating a RACH process being the first timer timing out.

[0193] In some embodiments, in a case where the first condition comprises: the first node fallbacks from a RACH-less handover procedure to a RACH handover procedure, the mobility related information comprises at least one of: an event that the first node fallbacks from the RACH-less procedure to the RACH handover procedure; a reason that the first node fallbacks from the RACH-less procedure to the RACH handover procedure; a list of CG resources configured by the first node; information of beams corresponding to the CG resources configured by the first node; measurement values of the beams corresponding to the CG resources configured by the first node; a beam quality threshold configured by the second node for the fallback event; a measurement value of a selected beam by the first node; configuration information of the RACH-less procedure; an application scenario of the RACH-less procedure.

[0194] In some embodiments, in a case where the first condition comprises: the first node link failure in a procedure of NTN resynchronization, the mobility related information comprises at least one of: position and velocity vector information of a satellite; orbit information of the satellite; a reference time; a time when a source satellite stops serving; a time when a target satellite starts serving; a time configured by a third timer for controlling a time of the procedure of resynchronization; a time configured by a T430 timer; a parameter for assisting the first node to perform resynchronization in a scenario of non-terrestrial network; a measurement value of a source beam and a target beam by the first node; a service interruption time for representing a time of service interruption due to the resynchronization of the NTN scenario.

[0195] In some embodiments, in a case where the first condition comprises: a number of resynchronizations in the procedure of NTN resynchronization is greater than a resynchronization number threshold; and / or, a time of resynchronization in the procedure of NTN resynchronization is greater than a resynchronization time threshold, the mobility related information comprises at least one of: an event that the number of resynchronizations is greater than the resynchronization number threshold; an event that the time of resynchronization is greater than the resynchronization time threshold; the resynchronization number threshold configured by the second node; the resynchronization time threshold configured by the second node; a number of actual resynchronizations performed by the first node; a time of actual resynchronization performed by the first node.

[0196] In a case where the functions of the above integrated modules are implemented in the form of hardware, the embodiments of the present disclosure provide a structure of a communication apparatus involved in the above embodiments. As shown in FIG. 6, the communication apparatus 800 includes a processor 802, a bus 804. In some embodiments, the communication apparatus can further include a memory 801. In some embodiments, the communication apparatus 800 can further include a communication interface 803.

[0197] The processor 802 can be a central processing unit, an application-specific processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic device, transistor logic, hardware components, or any combination thereof. The processor 802 can implement or execute various exemplary logical blocks, modules, and circuits described in connection with the embodiments of the present disclosure. The processor 802 can also be a combination of computing components, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0198] The communication interface 803 is configured to connect with other devices through a communication network. The communication network can be an Ethernet, a wireless access network, a wireless local area network (WLAN), and the like.

[0199] The memory 801 can be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage medium, or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited thereto.

[0200] As an implementation manner, the memory 801 can exist independently of the processor 802, and the memory 801 can be connected with the processor 802 through the bus 804, for storing instructions or program codes. When the processor 802 invokes and executes the instructions or program codes stored in the memory 801, the mobility management method provided by the embodiments of the present disclosure can be implemented. As another implementation manner, the memory 801 can also be integrated with the processor 802.

[0201] The bus 804 can be an extended industry standard architecture (EISA) bus or the like. The bus 804 can be divided into an address bus, a data bus, a control bus, and the like. For the convenience of representation, only one thick line is used in FIG. 6, but it does not mean that there is only one bus or only one type of bus.

[0202] Some embodiments of the present disclosure provide a computer readable storage medium (for example, a non-transitory computer readable storage medium) having stored computer program instructions, which, when executed on a computer, cause the computer to perform the mobility management method of any of the above embodiments.

[0203] Exemplarily, the above computer readable storage medium can include, but is not limited to, a magnetic storage device (for example, a hard disk, a floppy disk, a magnetic tape, etc.), an optical disc (for example, a compact disc (CD), a digital versatile disc (DVD), etc.), a smart card, and a flash memory device (for example, an erasable programmable read-only memory (EPROM), a card, a stick or a key drive, etc.). The various computer readable storage media described in the present disclosure can represent one or more devices and / or other machine readable storage media for storing information. The term "machine readable storage medium" can include, but is not limited to, a wireless channel and various other media capable of storing, containing and / or carrying instructions and / or data.

[0204] The embodiments of the present disclosure provide a computer program product containing instructions, which, when executed on a computer, cause the computer to perform the mobility management method of any of the above embodiments.

[0205] The above is merely specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any changes or replacements within the technical scope disclosed by the present disclosure should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A mobility management method applied to a first node, comprising: performing a first operation if a first condition is met in a random access free handover procedure of the first node; the first operation comprises at least one of the following: reporting mobility related information, triggering a random access procedure; the first condition is a condition that causes performance degradation or handover failure of the first node; the mobility related information is used to indicate at least one of the following: a reason for performance degradation of the first node, a reason for handover failure of the first node, related context information.

2. The method of claim 1, wherein, the first condition comprises at least one of the following: the first node is configured with configured grant (CG) resources but switches to a target cell based on dynamic grant (DG) resources; the first node has handover failure or radio link failure (RLF) within a first preset time period after successful handover; a first timer in a first scenario expires, the first timer being used to maintain uplink time synchronization; the first node falls back from the random access free handover procedure to a random access handover procedure; the first node has link failure in a non-terrestrial network (NTN) resynchronization procedure; a number of resynchronizations in the NTN resynchronization procedure is greater than a threshold number of resynchronizations; a time of resynchronization in the NTN resynchronization procedure is greater than a threshold time of resynchronization.

3. The method of claim 2, wherein, the first scenario comprises at least one of the following: layer one / layer two triggered mobility (LTM), random access free handover procedure, NTN resynchronization.

4. The method of claim 2, wherein, in a case where the first condition comprises: the first node being configured with the CG resources but switching to the target cell based on the DG resources; and / or, the first node having handover failure or the RLF within the first preset time period after successful handover, the first operation comprises: reporting the mobility related information.

5. The method of claim 4, wherein, the mobility related information comprises at least one of the following: CG resources configured by a second node; cell and beam information corresponding to the CG resources; information of a target cell and a target beam configured by the first node in an LTM procedure; a type of resources used by the first node.

6. The method of claim 1, wherein, in a case where the first condition comprises: the first timer in the first scenario expiring, the first operation comprises: reporting the mobility related information and / or triggering the random access procedure.

7. The method of claim 6, wherein, the mobility related information comprises at least one of the following: indication information of the first timer expiring; configuration of the first timer; configuration of a second timer, the second timer being used to control time of a handover procedure; configuration of a T304 timer; a reason for the first node initiating a random access channel (RACH) procedure is the first timer expiring.

8. The method of claim 1, wherein, in a case where the first condition comprises: the first node falling back from the random access free handover procedure to the random access handover procedure, the first operation comprises: reporting mobility related information.

9. The method of claim 8, wherein, the mobility related information comprises at least one of the following: an event of the first node falling back from a RACH-less procedure to a RACH handover procedure; a reason for the first node to fallback from the RACH-less procedure to the RACH switching procedure; a list of CG resources configured by the first node; information of a beam corresponding to a CG resource configured by the first node; a measurement value of a beam corresponding to a CG resource configured by the first node; a beam quality threshold configured by the second node for a fallback event; a measurement value of a selected beam by the first node; configuration information of the RACH-less procedure; an application scenario of RACH-less.

10. The method of claim 9, wherein, the configuration information comprises at least one of the following: timing advance, beam configuration information, CG configuration information.

11. The method of claim 9, wherein, the application scenario comprises at least one of the following: NTN, mobile integrated access and backhaul (mIAB).

12. The method of claim 1, wherein, in a case where the first condition comprises a link failure of the first node in a process of NTN resynchronization, the first operation comprises reporting the mobility related information.

13. The method of claim 12, wherein, the mobility related information comprises at least one of the following: position and velocity vector information of a satellite; orbit information of a satellite; reference time; time when a source satellite stops serving; time when a target satellite starts serving; time configured by a third timer for controlling time of a resynchronization process; time configured by a T430 timer; parameters for assisting the first node in resynchronization in a scenario of a non-terrestrial network (NTN); measurement values of a source beam and a target beam by the first node; service interruption time for representing time of service interruption due to resynchronization in an NTN scenario.

14. The method of claim 1, wherein, in a case where the first condition comprises that a number of resynchronizations in a process of NTN resynchronization is greater than a resynchronization number threshold; and / or, a time of resynchronization in a process of NTN resynchronization is greater than a resynchronization time threshold, the first operation comprises reporting the mobility related information.

15. The method of claim 14, wherein, the mobility related information comprises at least one of the following: an event that the number of resynchronizations is greater than the resynchronization number threshold; an event that the time of resynchronization is greater than the resynchronization time threshold; a resynchronization number threshold configured by the second node; a resynchronization time threshold configured by the second node; a number of resynchronizations actually performed by the first node; a time of resynchronization actually performed by the first node.

16. The method of claim 1, wherein, the mobility related information is carried in at least one of the following reports: a radio link failure (RLF) report, a RACH report, and a successful handover report (SHR). 17.A mobility management method applied to a second node, comprising: receiving mobility related information reported by a first node; the mobility related information is reported by the first node in a case where the first node satisfies a first condition in a random access free (RACH-less) procedure, wherein the first condition is a condition causing performance degradation or handover failure of the first node; and the mobility related information is used to indicate a reason for performance degradation or a reason for handover failure of the first node.

18. The method of claim 17, wherein, the first condition comprises at least one of the following: the first node is configured with a configured grant (CG) resource but switches to a target cell based on a dynamic grant (DG) resource. The first node fails in handover or radio link failure (RLF) occurs within a first preset time period after successful handover; The first timer in the first scenario expires, the first timer being used to maintain uplink time synchronization; The first node falls back from a handover procedure without random access to a handover procedure with random access; The first node fails in link in the process of non-terrestrial network (NTN) re-synchronization; The number of re-synchronizations in the process of NTN re-synchronization is greater than a threshold number of re-synchronizations; The time of re-synchronization in the process of NTN re-synchronization is greater than a threshold time of re-synchronization.

19. The method of claim 18, wherein, The first scenario includes at least one of the following: Layer one / layer two triggered mobility (LTM), handover procedure without random access, NTN re-synchronization.

20. The method of claim 18, wherein, In the case that the first condition includes that the first node is configured with the CG resource but switches to a target cell based on the DG resource, and / or the first node fails in handover or the radio link failure (RLF) occurs within the first preset time period after successful handover, the mobility-related information includes at least one of the following: CG resource configured by the second node; Cell and beam information corresponding to the CG resource; Information of a target cell and a target beam configured for the first node in the LTM procedure; Type of resource used by the first node.

21. The method of claim 18, wherein, In the case that the first condition includes that the first timer in the first scenario expires, the mobility-related information includes at least one of the following: Indication information of the expiration of the first timer; Configuration of the first timer; Configuration of a second timer, the second timer being used to control the time of a handover procedure; Configuration of a T304 timer; The first node initiates a random access channel (RACH) procedure due to the expiration of the first timer.

22. The method of claim 18, wherein, In the case that the first condition includes that the first node falls back from the handover procedure without random access to the handover procedure with random access, the mobility-related information includes at least one of the following: Event of the first node falling back from a RACH-less procedure to a RACH handover procedure; Reason of the first node falling back from the RACH-less procedure to the RACH handover procedure; CG resource list configured by the first node; Information of a beam corresponding to the CG resource configured by the first node; Measurement value of the beam corresponding to the CG resource configured by the first node; Beam quality threshold configured by the second node for the falling back event; Measurement value of a selected beam by the first node; Configuration information of the RACH-less procedure; Application scenario of RACH-less.

23. The method of claim 18, wherein, In the case that the first condition includes that the first node fails in link in the process of NTN re-synchronization, the mobility-related information includes at least one of the following: Position and velocity vector information of a satellite; Orbit information of the satellite; Reference time; Time when a source satellite stops serving; Time when a target satellite starts serving; Time when a third timer is configured, the third timer being used to control the time of a re-synchronization procedure; Time when a T430 timer is configured; a parameter for assisting the first node to perform re-synchronization in a scenario of a non-terrestrial network; a measurement value of the first node on a source beam and a target beam; a service interruption time, the service interruption time being used to represent a time of service interruption due to re-synchronization of the NTN scenario.

24. The method of claim 18, wherein, In a case where the first condition comprises: a number of re-synchronizations in a process of the NTN re-synchronization is greater than a re-synchronization number threshold; and / or, a time of re-synchronization in the process of the NTN re-synchronization is greater than a re-synchronization time threshold, the mobility-related information comprises at least one of: an event that the number of re-synchronizations is greater than the re-synchronization number threshold; an event that the time of re-synchronization is greater than the re-synchronization time threshold; the re-synchronization number threshold configured by the second node; the re-synchronization time threshold configured by the second node; a number of re-synchronizations actually performed by the first node; a time of re-synchronization actually performed by the first node.

25. A communications device, wherein comprise: a memory and a processor; the memory is coupled with the processor; the memory is used to store instructions executable by the processor; the processor executes the instructions to perform the method according to any one of claims 1 to 24.

26. A computer readable storage medium, wherein, The computer readable storage medium has stored thereon computer instructions which, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 24.

27. A computer program product, wherein, The computer program product contains computer instructions which, when executed on a computer, cause the computer to perform the method according to any one of claims 1 to 24.

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