Method and apparatus for supporting handover request in wireless communication system
By using a single conditional primary/secondary cell addition process in the wireless communication system, multiple conditional handover requests can be supported, solving the problems of signaling overhead and downtime, and achieving efficient conditional handover and secondary cell addition.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LG ELECTRONICS INC
- Filing Date
- 2024-10-31
- Publication Date
- 2026-05-29
Smart Images
Figure CN122123017A_ABST
Abstract
Description
Technical Field
[0001] The following description relates to wireless communication systems, and more specifically, to methods and apparatus for supporting conditional handover requests in wireless communication systems. Background Technology
[0002] Wireless access systems are being widely deployed to provide various types of communication services, such as voice and data. Typically, a wireless access system is a multiple access system that can support communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access (SC-FDMA).
[0003] Specifically, due to the need for large communication capacity in many communication devices, enhanced mobile broadband (eMBB) communication technologies have been proposed that improve upon existing radio access technologies (RAT). Furthermore, communication systems have been proposed that consider not only connecting multiple devices and objects to provide various services anytime, anywhere, but also reliability and latency-sensitive services / user equipment (UE). Various technical configurations for this purpose are being proposed. Summary of the Invention
[0004] Technical issues
[0005] This disclosure relates to devices and methods for efficiently supporting handover requests in wireless communication systems.
[0006] This disclosure relates to devices and methods for supporting multiple conditional handover (CHO) requests in a wireless communication system.
[0007] This disclosure relates to devices and methods for supporting multiple conditional handover (CHO) requests in a wireless communication system using a single conditional primary and secondary cell (PSCell) add (CPA) procedure.
[0008] This disclosure relates to an apparatus and method for requesting the addition of a conditional PSCell to at least one candidate target secondary node (SN) based on multiple CHO requests in a wireless communication system.
[0009] This disclosure relates to apparatus and method for providing at least one candidate target SN with a list of candidate target PCells determined for the candidate target SN in a wireless communication system.
[0010] This disclosure relates to an apparatus and method for providing information related to the number of allowed candidate PSCell configurations to at least one candidate target SN in a wireless communication system.
[0011] This disclosure relates to devices and methods for limiting the number of candidate PSCell configurations to be prepared by at least one candidate target SN in a wireless communication system.
[0012] This disclosure relates to a device and method for preparing at least one candidate PSCell configuration based on a permissible number of candidate PSCell configurations in a wireless communication system.
[0013] This disclosure relates to an apparatus and method for transmitting at least one candidate PSCell configuration prepared based on a permitted number of candidate PSCell configurations in a wireless communication system.
[0014] This disclosure relates to an apparatus and method for transmitting information in a wireless communication system that indicates the association between at least one prepared candidate PSCell configuration and a candidate target PCell.
[0015] The technical objectives to be achieved by this disclosure are not limited to those mentioned above, and those skilled in the art to which the technical configuration of this disclosure applies may consider other technical problems not mentioned below based on the embodiments of this disclosure described below.
[0016] Technical solution
[0017] As an example of this disclosure, a method may include: receiving at least one first message related to a conditional handover request of a terminal from a source primary node (MN); sending a second message related to an SN addition request to a first SN among candidate target secondary nodes (SNs) for the terminal; and receiving a third message related to the SN addition request from the first SN. The second message may include at least one of the following: a list of candidate target PCells determined by the source MN for the first SN among candidate target primary cells (PCells) for the conditional handover request, or information related to the number of allowed candidate primary / secondary cells (PSCells). The third message may include information related to candidate PSCell configurations prepared by the first SN based on the second message.
[0018] As an example of this disclosure, a method may include the following steps: receiving a second message related to a SN addition request from a target primary node (MN) of a terminal; and sending a third message related to the SN addition request to the target MN. The second message may include at least one of the following: a list of candidate target PCells determined by the source MN for a first SN among candidate target primary cells (PCells) in response to a conditional handover request, or information related to the number of allowed candidate primary / secondary cells (PSCells). The third message may include information related to the candidate PSCell configuration prepared by the first SN based on the second message.
[0019] As an example of this disclosure, an apparatus may include: a transceiver; and a processor coupled to the transceiver. The processor may control the transceiver to: receive at least one first message related to a conditional handover request of a terminal from a source primary node (MN); send a second message related to an SN addition request to a first SN among candidate target secondary nodes (SNs) for the terminal; and receive a third message related to the SN addition request from the first SN. The second message may include at least one of the following: a list of candidate target PCells determined by the source MN for the first SN among candidate target primary cells (PCells) for the conditional handover request, or information related to the number of allowed candidate primary / secondary cells (PSCells). The third message may include information related to a candidate PSCell configuration prepared by the first SN based on the second message.
[0020] As an example of this disclosure, an apparatus may include: a transceiver; and a processor coupled to the transceiver. The processor may control the transceiver to: receive a second message related to a SN addition request from a target primary node (MN) of a terminal; and send a third message related to the SN addition request to the target MN. The second message may include at least one of the following: a list of candidate target PCells determined by the source MN for a first SN among candidate target primary cells (PCells) in response to a conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells). The third message may include information related to the candidate PSCell configuration prepared by the first SN based on the second message.
[0021] As an example of this disclosure, a communication device may include: at least one processor; and at least one memory coupled to the at least one processor and storing instructions that, when executed by the at least one processor, indicate an operation. The operation may include: receiving at least one first message related to a conditional handover request from a source primary node (MN) of a terminal; sending a second message related to an SN addition request to a first SN among candidate target secondary nodes (SNs) for the terminal; and receiving a third message related to the SN addition request from the first SN. The second message may include at least one of the following: a list of candidate target PCells determined by the source MN for the first SN among candidate target primary cells (PCells) for a conditional handover request, or information related to the number of allowed candidate primary / secondary cells (PSCells). The third message may include information related to a candidate PSCell configuration prepared by the first SN based on the second message.
[0022] As an example of this disclosure, a non-transitory computer-readable medium stores at least one instruction that, when executed by at least one processor, causes a communication device to perform operations. The operations may include: receiving at least one first message from a source primary node (MN) of a terminal related to a conditional handover request of the terminal; sending a second message related to an SN addition request to a first SN among candidate target secondary nodes (SNs) for the terminal; and receiving a third message related to the SN addition request from the first SN. The second message may include at least one of the following: a list of candidate target PCells determined by the source MN for the first SN among candidate target primary cells (PCells) for the conditional handover request, or information related to the number of allowed candidate primary / secondary cells (PSCells). The third message may include information related to candidate PSCell configurations prepared by the first SN based on the second message.
[0023] The above aspects of this disclosure are merely some preferred embodiments of this disclosure, and those skilled in the art can deduce and understand various embodiments reflecting the technical features of this disclosure based on the detailed description described below.
[0024] Beneficial effects
[0025] The embodiments based on this disclosure can provide the following effects.
[0026] This disclosure can support multiple conditional handover requests in a wireless communication system.
[0027] The effects obtainable from the embodiments of this disclosure are not limited to those described above, and those skilled in the art to which the technical configuration of this disclosure applies can clearly obtain and understand other effects not mentioned below based on the following description of the embodiments of this disclosure. In other words, those skilled in the art can also obtain unexpected effects from implementing the configurations described in this disclosure based on the embodiments of this disclosure. Attached Figure Description
[0028] The accompanying drawings are provided to aid in understanding this disclosure and to provide embodiments of the disclosure as well as a detailed description. However, the technical features of this disclosure are not limited to the specific drawings, and the features disclosed in each drawing can be combined with each other to form new embodiments. Reference numerals in each drawing may indicate structural elements.
[0029] Figure 1 Examples of communication systems applied to this disclosure are illustrated.
[0030] Figure 2 Examples of UEs applicable to this disclosure are illustrated.
[0031] Figure 3An example of functional separation between NG-RAN and fifth-generation core (5GC) applicable to this disclosure is illustrated.
[0032] Figure 4 An example of a general architecture applicable to the fifth-generation (5G) system of this disclosure is illustrated.
[0033] Figure 5a and Figure 5b This illustrates a conditional switching process with auxiliary nodes.
[0034] Figure 6a and Figure 6b An example of a process for supporting multiple conditional switching requests according to an embodiment of the present disclosure is illustrated.
[0035] Figure 7 An example of a process for receiving PSCell configuration information according to an embodiment of the present disclosure is illustrated.
[0036] Figure 8 An example of a process for sending PSCell configuration information according to an embodiment of the present disclosure is illustrated. Detailed Implementation
[0037] The following embodiments are combinations of the components and features of this disclosure in a predetermined form. Unless otherwise explicitly stated, each component or feature may be considered optional. Each component or feature may be implemented without combination with other components or features. Furthermore, embodiments of this disclosure can be configured by combining some components and / or features. The order of operations described in the embodiments of this disclosure may be changed. Some configurations or features of one embodiment may be included in another embodiment, or may be replaced by corresponding configurations or features of another embodiment.
[0038] In the description of the accompanying drawings, processes or steps that may obscure the essential points of this disclosure are not described, nor are processes or steps that can be understood by those skilled in the art.
[0039] Throughout this specification, when a part is referred to as “comprising” or “including” a component, it means that it may also include other components rather than exclude them, unless explicitly stated to the contrary. Furthermore, terms such as “unit,” “apparatus,” and “module” described in the specification refer to a unit that performs at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. Additionally, the words “a,” “an,” “the,” and similar related terms may be used in the context of describing this disclosure (particularly in the context of the appended claims) to mean both singular and plural, unless otherwise stated herein or clearly contradicted by the context.
[0040] In this specification, embodiments of the present disclosure have been described regarding the data transmission and reception relationship between a base station and a mobile station. Here, a base station is understood as a terminal node of a network that communicates directly with a mobile station. Specific operations described herein as being performed by the base station may, in some cases, be performed by upper-layer nodes of the base station.
[0041] In other words, various operations for communicating with a mobile station in a network consisting of multiple network nodes, including a base station, can be performed by the base station or other network nodes besides the base station. In this case, "base station" can be replaced by terms such as fixed station, node B, eNB (eNode B), gNB (gNode B), ng-eNB, advanced base station (ABS), or access point.
[0042] Furthermore, in embodiments of this disclosure, the term "terminal" may be replaced by terms such as User Equipment (UE), Mobile Station (MS), Subscriber Station (SS), Mobile Subscriber Station (MSS), Mobile Terminal, or Advanced Mobile Station (AMS).
[0043] Furthermore, the transmitting end refers to a fixed and / or mobile node that provides data or voice services, and the receiving end refers to a fixed and / or mobile node that receives data or voice services. Therefore, in the uplink case, the mobile station can be the transmitting end, and the base station can be the receiving end. Similarly, in the downlink case, the mobile station can be the receiving end, and the base station can be the transmitting end.
[0044] Implementations of this disclosure may be supported by standard documents disclosed in at least one of the radio access systems including the IEEE 802.xx system, the 3rd Generation Partnership Project (3GPP) system, the 3GPP Long Term Evolution (LTE) system, the 3GPP 5th Generation (5G) New Radio (NR) system, and the 3GPP2 system. Specifically, implementations of this disclosure may be supported by 3GPP Technical Specification (TS) 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321, and 3GPP TS 38.331 documents.
[0045] Furthermore, the embodiments of this disclosure can be applied to other wireless access systems and are not limited to the systems described above. For example, they can be applied to systems subsequently used after 3GPP 5G NR systems, and are not limited to any particular system.
[0046] In other words, obvious steps or parts not described in the embodiments of this disclosure can be referred to the descriptions in the aforementioned documents. Furthermore, all terms disclosed in this document can be described using the aforementioned standard documents.
[0047] In the following, preferred embodiments according to this disclosure will be described in detail with reference to the accompanying drawings. The preferred embodiments will be described below in conjunction with the accompanying drawings. Figure 1 The detailed description disclosed herein is intended to describe exemplary embodiments of this disclosure and is not intended to represent the only implementation of the technical configurations of this disclosure.
[0048] In addition, specific terminology used in the embodiments of this disclosure is provided to aid in understanding this disclosure, and the use of such specific terminology may be changed to other forms without departing from the technical spirit of this disclosure.
[0049] The following technologies can be applied to various wireless access systems, such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access (SC-FDMA).
[0050] For clarity, the following description is based on 3GPP communication systems (e.g., LTE, NR, etc.), but the technical spirit of this disclosure is not limited thereto. LTE can refer to technologies from 3GPP TS 36.xxx version 8 onwards. Specifically, LTE technologies from 3GPP TS 36.xxx version 10 onwards can be referred to as LTE-A, and LTE technologies from 3GPP TS 36.xxx version 13 onwards can be referred to as LTE-A pro. 3GPP NR can refer to technologies from TS 38.xxx version 15 onwards. 3GPP 6G can refer to technologies from TS version 17 and / or version 18 onwards. "xxx" refers to the detailed standard document number. LTE / NR / 6G can be collectively referred to as the 3GPP system.
[0051] For background information, terminology, abbreviations, etc., used in this disclosure, please refer to the descriptions in previously published standard documents. For example, refer to standard documents 36.xxx and 38.xxx.
[0052] For the terminology, abbreviations, and other background technologies that may be used in this document, please refer to the following standard documents previously published. Specifically, for LTE / Evolved Packet System (EPS) related terminology, abbreviations, and other background technologies, please refer to the 36.xxx series, 23.xxx series, and 24.xxx series; and for New Radio (NR) / 5G System (5GS) related terminology, abbreviations, and other background technologies, please refer to the 38.xxx series, 23.xxx series, and 24.xxx series.
[0053] In the following text, this specification is described based on the terminology defined above.
[0054] The three main demand areas for 5G include (1) enhanced mobile broadband (eMBB), (2) massive machine-type communications (mMTC) and (3) ultra-reliable and low-latency communications (URLLC).
[0055] Some use cases may require multiple regions for optimization, while others may focus on only one key performance indicator (KPI). 5G supports these diverse use cases in a flexible and reliable manner.
[0056] Communication systems applicable to this disclosure
[0057] While not limited thereto, the various descriptions, functions, processes, proposals, methods and / or operation flowcharts disclosed in this document can be applied to various fields requiring wireless communication / connectivity between devices (e.g., 5G).
[0058] More specific examples are illustrated below with reference to the accompanying drawings. In the following drawings / description, the same reference numerals may refer to the same or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise described.
[0059] Figure 1 Examples of communication systems applied to this disclosure are illustrated.
[0060] Reference Figure 1The communication system 100 applied in this disclosure includes wireless devices, base stations, and networks. Here, a wireless device refers to a device that performs communication using wireless access technologies (e.g., 5G NR, LTE) and may be referred to as a communication / wireless / 5G device. While not limited thereto, wireless devices may include robots 100a, vehicles 100b-1 and 100b-2, extended reality (XR) devices 100c, handheld devices 100d, home appliances 100e, Internet of Things (IoT) devices 100f, and artificial intelligence (AI) devices / servers 100g. For example, vehicles may include vehicles equipped with wireless communication capabilities, autonomous vehicles, vehicles capable of performing vehicle-to-vehicle communication, etc. Here, vehicles 100b-1 and 100b-2 may include unmanned aerial vehicles (UAVs) (e.g., drones). XR device 100c includes augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and can be implemented as a head-up display (HUD) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Handheld device 100d can include smartphones, smart tablets, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliance 100e can include TVs, refrigerators, washing machines, etc. IoT device 100f can include sensors, smart meters, etc. For example, base station 120 and network 130 can also be implemented as wireless devices, and a specific wireless device 120a can operate as a base station / network node for other wireless devices.
[0061] Wireless devices 100a to 100f can connect to network 130 via base station 120. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 100g via network 130. Network 130 can be configured using 3G, 4G (e.g., LTE), or 5G (e.g., NR) networks, etc. Wireless devices 100a to 100f can communicate with each other via base station 120 / network 130, but can also communicate directly (e.g., sidelink communication) without going through base station 120 / network 130. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). Furthermore, IoT device 100f (e.g., sensor) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.
[0062] Wireless communication / connections 150a, 150b, and 150c can be established between wireless devices 100a to 100f / base station 120 and between base stations 120 / 120. Here, the wireless communication / connection can be implemented through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication 150a, sidelink communication 150b (or D2D communication), and inter-base station communication 150c (e.g., relay, integrated access backhaul (IAB)). Through wireless communication / connections 150a, 150b, and 150c, wireless devices and base stations / wireless devices, as well as base stations and base stations, can transmit / receive wireless signals to each other. For example, wireless communication / connections 150a, 150b, and 150c can transmit / receive signals through various physical channels. Therefore, based on various proposals of this disclosure, at least some of the following can be performed: various configuration information setting processes for wireless signal transmission / reception, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.
[0063] Figure 2 Examples of UEs applicable to this disclosure are illustrated.
[0064] Reference Figure 2 The UE 200 may include a processor 202, a memory 204, a transceiver 206, one or more antennas 208, a power management module 241, a battery 242, a display 243, a keypad 244, a subscriber identification module (SIM) card 245, a speaker 246, and a microphone 247.
[0065] Processor 202 may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. Processor 202 may be configured to control one or more other components of UE 200 to implement the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed herein. A wireless interface protocol layer may be implemented in processor 202. Processor 202 may include an ASIC, other chipsets, logic circuits, and / or data processing devices. Processor 202 may be an application processor. Processor 202 may include at least one of a DSP, a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator).
[0066] Memory 204 is operatively coupled to processor 202 and can store various information for operating processor 202. Memory 204 may include ROM, RAM, flash memory, memory card, storage medium, and / or other storage devices. When implemented in software, the techniques described herein can be implemented using modules (e.g., processes, functions, etc.) that perform the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Modules may be stored in memory 204 and executed by processor 202. Memory 204 may be implemented within or outside processor 202, in which case it may be communicatively coupled to processor 202 using various methods known in the art.
[0067] Transceiver 206 is operatively coupled to processor 202 and can transmit and / or receive wireless signals. Transceiver 206 may include a transmitter and a receiver. Transceiver 206 may include baseband circuitry for processing radio frequency signals. Transceiver 206 may control one or more antennas 208 to transmit and / or receive wireless signals.
[0068] The power management module 241 can manage the power used for the processor 202 and / or transceiver 206. The battery 242 can supply power to the power management module 241.
[0069] The display 243 can output the results processed by the processor 202. The keypad 244 can receive input for use by the processor 202. The keypad 244 can be displayed on the display 243.
[0070] The SIM card 245 is an integrated circuit used to securely store the International Mobile Subscriber Identity (IMSI) and related keys, and can be used to identify and authenticate subscribers in mobile devices such as mobile phones or computers. Furthermore, contact information can be stored on multiple SIM cards.
[0071] Speaker 246 can output sound-related results processed by processor 202. Microphone 247 can receive sound-related input for use by processor 202.
[0072] In the implementation described herein, the UE can operate as a transmitting device in the uplink and as a receiving device in the downlink. In the implementation described herein, the base station can operate as a receiving device in the UL and as a transmitting device in the DL. In this specification, the base station can be referred to as Node B, eNode B (eNB), or gNB, and is not limited to any specific form.
[0073] Furthermore, for example, the UE can be implemented in various forms depending on the use case / service. The UE can be configured from various components, devices / parts, and / or modules. For example, each UE may include a communication device, a control device, a memory device, and additional components. The communication device may include communication circuitry and transceivers. For example, the communication circuitry may include one or more processors and / or one or more memories. For example, the transceiver may include one or more transceivers and / or one or more antennas. The control device is electrically connected to the communication device, memory device, and additional components, and can control the overall operation of each UE. For example, the control device can control the electrical / mechanical operation of each UE based on programs / code / instructions / information stored in the memory device. The control device can transmit information stored in the memory device to external sources (e.g., other communication devices) via a wireless / wired interface through the communication device, or store information received from external sources (e.g., other communication devices) in the memory device via a wireless / wired interface through the communication device.
[0074] Additional components can be configured differently depending on the type of UE. For example, additional components may include at least one of a power unit / battery, input / output (I / O) devices (e.g., audio I / O ports, video I / O ports), drive units, and computing units. Furthermore, the UE can be implemented in, but is not limited to, the following forms: robot (…). Figure 1 100a in the middle), vehicles ( Figure 1 100b-1 and 100b-2 in the series), XR device ( Figure 1 100c in the middle), portable device ( Figure 1 100d in the middle), household appliances ( Figure 1 100e in the middle), IoT devices ( Figure 1 100f), digital broadcasting terminals, holographic devices, public safety devices, MTC devices, medical devices, fintech devices (or financial devices), security devices, climate / environment devices, AI servers / devices ( Figure 1 100g in the middle), base station ( Figure 1 (120 in the middle) network nodes. The UE can be used in mobile or fixed locations depending on the use case / service.
[0075] All the various components, devices / parts, and / or modules of the UE can be connected to each other via wired interfaces, or at least some can be wirelessly connected via communication devices. Furthermore, each component, device / part, and / or module of the UE may include one or more elements. For example, the control unit may be configured with one or more processor groups. For instance, the control unit may be configured with a group of communication control processors, application processors (APs), electronic control units (ECUs), graphics processing units, and memory control processors. As another example, the memory device may be configured with RAM, dynamic RAM (DRAM), ROM, flash memory, volatile memory, non-volatile memory, and / or combinations thereof.
[0076] 5G system architecture applicable to this disclosure
[0077] 5G systems are advanced technologies derived from fourth-generation LTE mobile communication technology. They support new radio access technologies (RATs), extended LTE (eLTE) as an extension of LTE, and non-3GPP (e.g., WLAN) access through the evolution or clean state architecture of existing mobile communication networks.
[0078] 5G systems are service-defined, and the interaction between network functions (NFs) within the 5G system architecture can be represented in the following two ways: - Reference point representation: Represents the interaction between NF services within an NF described by a point-to-point reference point (e.g., N11) between two NFs (e.g., AMF and SMF).
[0079] - Service-based representation: Network functions within the control plane (CP) (e.g., AMF) allow other authorized network functions to access their services. This representation may also include point-to-point reference points where necessary.
[0080] The 5G core (5GC) can include various components, including Access and Mobility Management Function (AMF), Session Management Function (SMF), Policy Control Function (PCF), User Plane Function (UPF), Application Function (AF), Unified Data Management (UDM), and Non-3GPP Interoperability Function (N3IWF).
[0081] The UE connects to the data network via a UPF through a Next Generation Radio Access Network (NG-RAN) including a gNB. The UE can receive data services through untrusted non-3GPP access, such as a Wireless Local Area Network (WLAN). To connect non-3GPP access to the core network, an N3IWF can be deployed.
[0082] The N3IWF manages interoperability between non-3GPP access points and 5G systems. When a UE connects to a non-3GPP access point (e.g., WiFi known as IEEE 802.11), the UE can connect to the 5G system via the N3IWF. The N3IWF communicates with the AMF (Advanced Management Function) for control signaling and connects to the UPF (Uplink Function) via the N3 interface for data transmission.
[0083] AMF can manage access and mobility in 5G systems. AMF can perform functions to manage Non-Access Stratum (NAS) security. AMF can perform functions to handle mobility in idle states.
[0084] UPF performs gateway functions for sending and receiving user data. UPF nodes can perform all or part of the user plane functions of a Serving Gateway (S-GW) and Packet Data Network Gateway (P-GW) for fourth-generation mobile communications.
[0085] The UPF serves as the boundary point between the Next Generation RAN (NG-RAN) and the core network, and is an element that maintains the data path between the gNB and the SMF. Furthermore, the UPF acts as a mobility anchor point when the UE moves across an area served by the gNB. The UPF can perform the function of disposing of PDUs. For mobility within the NG-RAN (e.g., NG-RAN defined after 3GPP Release 15), the UPF can route packets. Additionally, the UPF can serve as an anchor point for mobility with other 3GPP networks (e.g., RANs defined before 3GPP Release 15), such as UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access Network (UTRAN), Evolved UTRAN (E-UTRAN), or GSM (Global System for Mobile Communications) / EDGE (Global Evolution Enhanced Data Rate) Radio Access Network (GERAN). The UPF can correspond to the termination point of the data interface toward the data network.
[0086] PCF is the node that controls operator policies. AF is the server that provides various services to UE. UDM is the server that manages subscriber information, such as the Home Subscriber Server (HSS) in fourth-generation mobile communications. UDM 460 stores and manages subscriber information in the Unified Data Repository (UDR).
[0087] The SMF can perform the function of allocating Internet Protocol (IP) addresses to UEs. Furthermore, the SMF can control Protocol Data Unit (PDU) sessions.
[0088] For ease of description below, reference numerals for AMF, SMF, PCF, UPF, AF, UDM, N3IWF, gNB, or UE may be omitted, and reference may be made to the descriptions in standard documents previously published in this document.
[0089] Figure 3 An example of functional separation between NG-RAN and fifth-generation core (5GC) applicable to this disclosure is illustrated.
[0090] Reference Figure 3 The UE connects to the data network (DN) via the next-generation RAN. Control plane function (CPF) nodes perform all or part of the functions of the mobility management entity (MME) for fourth-generation mobile communications, as well as all or part of the control plane functions of the serving gateway (S-GW) and PDN gateway (P-GW). CPF nodes include the AMF and SMF.
[0091] UPF nodes perform the functions of a gateway through which user data is sent and received.
[0092] The Authentication Server Function (AUSF) authenticates and manages the UE. The Network Slice Selection Function (NSSF) is a node used for network slicing as described below.
[0093] Network Open Function (NEF) provides a mechanism to securely open up 5G core services and functions.
[0094] Figure 3 The reference points shown are as follows: N1 represents the reference point between the UE and AMF. N2 represents the reference point between (R)AN and AMF. N3 represents the reference point between (R)AN and UPF. N4 represents the reference point between SMF and UPF. N5 represents the reference point between PCF and AF. N6 represents the reference point between UPF and DN. N7 represents the reference point between SMF and PCF. N8 represents the reference point between UDM and AMF. N9 represents the reference point between UPFs. N10 represents the reference point between UDM and SMF. N11 represents the reference point between AMF and SMF. N12 represents the reference point between AMF and AUSF. N13 represents the reference point between UDM and AUSF. N14 represents the reference point between AMFs. N15 represents the reference point between PCF and AMF in non-roaming scenarios, and the reference point between AMF and PCF of the visited network in roaming scenarios. N16 represents the reference point between SMFs. N22 represents the reference point between AMF and NSSF. N30 represents the reference point between PCF and NEF. N33 can represent the reference point between AF and NEF, and the above entities and interfaces can be configured with reference to the descriptions in the standard documents previously published in this document. N58 represents the reference point between AMF and NSSAAF. N59 represents the reference point between UDM and NSSAAF. N80 represents the reference point between AMF and NSACF. N81 represents the reference point between SMF and NSACF.
[0095] The radio interface protocol is based on the 3GPP radio access network specification. The radio interface protocol consists of a physical layer, a data link layer, and a network layer horizontally, and is vertically divided into a user plane for data information transmission and a control plane for control signal (signaling) transmission.
[0096] The protocol layer can be divided into L1 (layer-1), L2 (layer-2), and L3 (layer-3) based on the three layers of the Open Systems Interconnection (OSI) reference model, which is widely known in communication systems.
[0097] Each wireless protocol layer is described below. Figure 4 An example of a general architecture applicable to the fifth-generation (5G) system of this disclosure is illustrated.
[0098] Reference Figure 4 The access layer (AS) may include the physical (PHY) layer, the medium access control layer, the radio link control (RLC) layer, the packet data convergence protocol (PDCP) layer, and the radio resource control (RRC) layer, and the operation of each layer can be referenced to the descriptions in the standard documents previously published in this document.
[0099] Specific Implementation Methods of This Disclosure
[0100] This disclosure relates to apparatus and methods for supporting conditional handover (CHO) requests in a wireless communication system. More specifically, this disclosure relates to apparatus and methods for supporting multiple CHO requests in a wireless communication system using a single conditional primary / secondary cell (PSCell) add (CPA) procedure.
[0101] In this disclosure, conditional handover (CHO) includes handover performed only when execution conditions are met, and conditional primary / secondary cell addition (CPA) procedure includes PSCell addition procedure performed only when PSCell addition execution conditions are met.
[0102] A primary cell group (MCG) is a serving cell group associated with a primary node (MN) in a Multiple Radio Dual Connectivity (MR-DC) system, and includes the primary cell (PCell) and may optionally include one or more secondary cells (SCells). The primary node is the radio access node in the MR-DC that provides control plane connectivity to the core network, and may include at least one of the primary eNB in an E-UTRA-NR Dual Connectivity (EN-DC), the primary ng-eNB in an NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), or the primary gNB in an NR-NR Dual Connectivity (NR-DC) and NR-E-UTRA Dual Connectivity (NE-DC). The PCell is the primary cell of the primary cell group.
[0103] A secondary cell group (SCG) is a serving cell group in an MR-DC associated with a secondary node (SN), and includes a PSCell, and may optionally include one or more SCells. A secondary node is a radio access node in the MR-DC that does not have a control plane connection to the core network and can provide additional resources to the UE. A secondary node may include at least one of a secondary en-gNB in an EN-DC, a secondary ng-eNB in an NE-DC, or a secondary gNB in an NR-DC and an NGEN-DC. The PSCell is the primary cell of the secondary cell group.
[0104] Based on the Rel-18 Network Mobility Enhancement Work Item (WI), the following has been documented to extend Conditional Handover (CHO) using the NR-DC architecture defined in Rel-17.
[0105]
[0106] 3. Judgment
[0107] When a UE moves from the coverage area of one cell to another, a serving cell change is required. The current serving cell change is triggered by L3 measurements and completed via a reconfiguration triggered by RRC signaling, which synchronizes changes for PCell and PSCell, and releases / additions for SCells where applicable. All cases involve a full L2 (and L1) reset, resulting in longer latency, greater overhead, and longer downtime compared to beam-switching mobility. The goal of L1 / L2 mobility enhancement is to enable serving cell changes via L1 / L2 signaling to reduce latency, overhead, and downtime.
[0108] In Rel-17 Conditional PSCell Change (CPC) / Conditional PSCell Addition (CPA), a UE configured with CPC / CPA must release the CPC / CPA configuration upon completing random access to the target PSCell. Therefore, the UE has no opportunity to perform subsequent CPC / CPA without prior CPC / CPA reconfiguration and reinitialization from the network. This increases cell change latency and signaling overhead, especially with frequent SCG changes during FR2 operation. Therefore, MR-DC with selective activation of cell groups aims to enable subsequent CPC / CPA after an SCG change without requiring reconfiguration and reinitialization of CPC / CPA preparation from the network. This results in reduced signaling overhead and shorter downtime for SCG changes.
[0109] Currently, CHO and MR-DC cannot be configured simultaneously. This limits the usefulness of both features when MR-DC is configured. If this was not addressed in Rel-17, Rel-18 should specify a mechanism for configuring CHO and MR-DC simultaneously. However, this alone may not be sufficient to optimize MR-DC mobility, as the radio link quality of the conditionally configured PSCell may be insufficient or not the optimal candidate PSCell when the UE accesses the target PCell, potentially impacting UE throughput. To mitigate this throughput impact, Rel-18 CHO+MRDC can consider CHO for CPC / CPA, including the target MCG and multiple candidate SCGs.
[0110] 4. Objectives
[0111] 4.1 Target of SI or core WI or test WI
[0112] The specific objective of this work project is: 1. To specify the mechanisms and processes for L1 / L2-based inter-cell mobility for mobility latency reduction: - Configure and maintain multiple candidate cells to allow for rapid application of configurations for candidate cells [RAN2, RAN3] Dynamic handover mechanisms in candidate serving cells (including SpCell and SCell) based on potential L1 / L2 signaling application scenarios [RAN2, RAN1] L1 enhancements for inter-cell beam management include L1 measurement and reporting, as well as beam indication [RAN1, RAN2]. - Note 1: Early RAN2 involvement is necessary, including further clarifying the possibility of interaction between this project symbol and previous project symbols. - Note 2: Only SSB-based L1 measurements are supported in this version.
[0113] Scheduled advance management [RAN1, RAN2] If needed, CU-DU interface signaling is used to support L1 / L2 mobility [RAN3]. Note 3: FR2-specific enhancements (if any) are not excluded.
[0114] Note 4: The L1 / L2-based inter-cell mobility process is applicable to the following scenarios: - For independent, CA, and NR-DC cases involving changes to the serving cell within a CG, the MCG takes precedence. - Intra-DU and intra-CU DU scenarios (applicable to standalone and CA: no new RAN interfaces expected) - Both within and between frequencies - Both FR1 and FR2 - The source cell and the target cell can be synchronous or asynchronous.
[0115] 2. To specify the mechanism and process for selectively activating NR-DC via L3 enhancement for cell groups (at least for SCGs): Allows subsequent cell group changes after a CG change without reconfiguration and re-initiation of CPC / CPA [RAN2, RAN3, RAN4]. Note 5: A coordinated RRC modeling approach for objectives 1 and 2 can be considered to minimize the workload in RAN2.
[0116] 3. For CHO[RAN3] in NR-DC, which includes both the target MCG and the target SCG: Specified data forwarding optimization; and If necessary, specify a solution to avoid unnecessary signaling exchange between the source MN and the target SN.
[0117] 4. To specify the CHO [RAN3, RAN2] for CPC / CPA in NR-DC, including the target MCG and candidate SCG. CHOs, including those for target MCG and target SCG, were used as a baseline. 5. To specify the core RRM requirements (if applicable) [RAN4] for the following: Inter-cell mobility based on L1 / L2 Enhanced CHO configuration solved by this WI 6. To specify RF requirements (if necessary) covering inter-frequency L1 / L2 based mobility [RAN4].
[0118] 7. To investigate and specify how to reuse idle / inactive mode measurements to be reported during and / or after RRC connection establishment / recovery to improve SCell / SCG establishment latency [RAN4, RAN2], the following is included: The availability and validation of idle / inactive mode measurement results to be reported [RAN4]; and The definition of the corresponding RRM requirements [RAN4]; and If necessary, define the corresponding signaling support [RAN2] based on the RAN4 results.
[0119] Note 6: RAN4 will coordinate with RAN2 at the appropriate time to begin work.
[0120] Note 7: R4-2220415 is used as a baseline for future work in RAN4.
[0121] Note 8: Apart from the scenarios mentioned above, measurements for idle / inactive modes and enhancements to UE behavior in idle / inactive modes are not included.
[0122]
[0123] In other words, in a Rel-17 conditional handover with NR-DC, each candidate PCell configuration (e.g., an MCG configuration) can be associated with an SCG configuration. Therefore, once a conditional handover for a specific target PCell is performed, the SCG configuration associated with the corresponding target PCell configuration can be used together with the selected target PCell for NR-DC operation. This is described in section 10.19 of TS37.340, which defines inter-MN conditional handover (inter-MN CHO).
[0124] Figure 5a and Figure 5b A conditional switching process with a secondary node is illustrated. Figure 5 corresponds to Figure 10.19.2-1 in section 10.19.2 of TS 37.340. (As...) Figure 5a and Figure 5b As shown, during the conditional handover process using NR-DC, different SNs or the same SN can be selected based on how the corresponding SCG configuration for each candidate target PCell is prepared.
[0125] In Rel-18, work is underway to extend the architecture to allow the UE to conditionally select a PSCell from multiple pre-configured PSCells, similar to conditional handover. The selected PSCell can be referred to as a candidate SCG. The goal of this work is to leverage the existing Rel-17 CPA mechanism and combine it with the CHO mechanism.
[0126] While one or more candidate PSCell configurations can be prepared for each PCell requested for a conditional handover, Rel-17 conditional handover with NR-DC allows at most one SCG configuration associated with each PCell requested for a conditional handover. In Rel-17, a separate SN addition procedure is allowed for the target MN to trigger toward the same SN. For example, for each of parallel conditional handover requests with different received PCells, a separate SN addition procedure is allowed for the target MN to trigger toward the same SN. Alternatively, depending on the implementation of the target MN, it is allowed to trigger only one SN addition procedure toward the SN, and use the same CG-Config for all parallel conditional handover requests. Alternatively, a combination of the two methods described above is also possible.
[0127] For example, the former approach makes sense when the PDU session or DRB requested to be established from the source is different for different PCells with parallel conditional switching requests from the source.
[0128] On the other hand, the latter approach also makes sense when the PDU session or DRB requested to be established from the source is the same for different PCells of parallel conditional handover requests from the source. In this case, a single SN add procedure is sufficient to prepare only one SCG configuration toward the same SN and combine it with multiple conditional handover requests. This approach can be equivalently applied to Rel-18 conditional handovers with candidate SCGs. That is, the same approach can be equivalently applied to conditional handover procedures that use CPA instead of the traditional SN add procedure.
[0129] The latter approach is more suitable for conditional switching within a master node (MN-based CHO) scenario, where the conditional switch is prepared within the same master node. For example, the latter approach is more suitable for... Figure 5a and Figure 5b In scenarios where the source MN and target MN are merged into a single MN, it is more likely that a parallel SN addition process for different candidate target PCells towards the same SN will not be necessary.
[0130] Although both methods are allowed in Rel-17, the second method, which uses a single CPA procedure instead of parallel CPA towards the candidate target SN, cannot accommodate multiple conditional handover requests. Furthermore, it is unclear how this method will work in Rel-18 with candidate SCGs.
[0131] Therefore, this disclosure proposes a mechanism to support multiple CHO requests in a target MN by using a single conditional PSCell Addition (CPA) procedure toward each candidate target SN when preparing a Rel-18 handover with candidate SCG configuration for a UE.
[0132] This disclosure presents a procedure for supporting multiple conditional handover requests in a target MN using a single CPA procedure directed to each candidate target SN. This disclosure can be applied when preparing a Rel-18 conditional handover for a UE with candidate SCG configurations.
[0133] Figure 6a and Figure 6b An example is illustrated of a process supporting multiple conditional switching requests according to an embodiment of the present disclosure. Specifically, Figure 6a and Figure 6b An example is shown of a procedure that uses a single CPA procedure to support multiple conditional handover requests in a Rel-18 conditional handover with candidate SCGs.
[0134] Reference Figure 6a and Figure 6b In step S601, source MN 620 sends multiple handover request messages to target MN 630. Specifically, source MN 620 determines a conditional handover for the UE based on measurements obtained from UE 610. Source MN 620 identifies candidate target PCells suitable for the conditional handover of the UE and initiates a handover preparation process by sending a handover request message for each of the candidate target PCells to target MN 630 serving the candidate target PCells. Depending on the selected candidate target PCells, the handover preparation process can be triggered in parallel towards each target MN, or it can be triggered towards one or more target MNs. For each candidate target PCell, each handover request message may include the maximum number of conditional reconfigurations (condReconfig) allowed to be prepared by the requested target MN.
[0135] In step S603, target MN 630 determines at least one candidate target SN to prepare CPA for the UE. When a conditional handover request message for multiple PCells currently being served is received from source MN 620, target MN 630 can determine the multiple PCells as candidate target PCells for conditional handover for the UE. Target MN 630 can perform admission control for the candidate target PCells for which conditional handover has been requested, and can determine at least one candidate target SN for which CPA needs to be prepared.
[0136] In step S605, target MN 630 sends SN add request messages to at least one candidate target SN 640-1 and SN 640-2. Once at least one candidate target SN 640-1 and SN 640-2 are determined, target MN 630 can initiate a CPA procedure towards each of the determined candidate target SN 640-1 and SN 640-2 by sending an SN add request message to each of the determined candidate target SN 640-1 and SN 640-2. The SN add request message can be a request message for adding a conditional PSCell and can be referred to as a CPA request message. The CPA request message can include a list of candidate target PCells determined for the candidate target SN from the candidate target PCells requested from the source MN for conditional handover. The candidate target PCells requested from the source MN can include PCells corresponding to the handover request messages received from the source MN. The CPA request message can also include the total number of PSCell configurations allowed by each candidate target SN for the candidate target PCell list. In step S601, the total number of allowed PSCell configurations can be determined based on the maximum number of conditional reconfigurations indicated by the source MN for each candidate target PCell. Alternatively, the CPA request message may include the number of PSCell configurations allowed per PCell to be prepared by each candidate target SN. The number of PSCell configurations allowed per PCell can be determined based on the maximum number of allowed conditional reconfigurations indicated by the source MN for each candidate target PCell that has been requested for conditional switching in step S601.
[0137] In step S607, at least one candidate target SN 640-1 and SN 640-2 send an SN Add Request Confirmation message to target MN 630. Upon receiving the CPA request message, at least one candidate target SN 640-1 and SN 640-2 performs admission control for the candidate PSCell and prepares the candidate PSCell configuration. At this time, the number of candidate PSCell configurations to be prepared does not exceed the number allowed by the CPA request message. For example, the number of candidate PSCell configurations to be prepared for the candidate target PCell list in each of the at least one candidate target SN 640-1 and SN 640-2 can be limited to not exceed the total number of allowed candidate PSCell configurations. According to one implementation, the number of candidate PSCell configurations to be prepared can be limited based on each PCell. For example, when target MN 630 requests a per-PCell limit, the number of candidate PSCell configurations to be prepared for each candidate target PCell in at least one of candidate targets SN 640-1, SN 640-2 can be limited to not exceed the maximum number of candidate PSCell configurations allowed per candidate target PCell. At least one candidate target SN 640-1, SN 640-2 provides target MN 630 with a list of CG-Configs, which includes information related to each prepared candidate PSCell configuration. That is, at least one candidate target SN 640-1, SN 640-2 sends an SN Add Request Confirmation Message including the CG-Config list to target MN 630. The SN Add Request Confirmation Message can be a response message to a CPA Request Message. The SN Add Request Confirmation Message can also include information about how each CG-Config prepared for each selected candidate PSCell is associated with which candidate target PCell in the list of candidate target PCells indicated by the CPA Request Message.
[0138] In step S609, target MN 630 sends Xn-U address indication messages to at least one candidate target SN 640-1 and SN 640-2. When a bearer for SN termination using MCG resources is ready, target MN 630 can use subsequent Xn-U address indication messages to provide Xn-U downlink (DL) transport network layer (TNL) information. That is, subsequent Xn-U address indication messages may include Xn-U DL TNL information.
[0139] In step S611, target MN 630 sends a handover request confirmation message to source MN 620. Based on the candidate PSCell configurations prepared by at least one candidate target SN 640-1, SN 640-2, and the association between each candidate PSCell configuration and a specific candidate target PCell among the candidate target PCells for which a conditional handover from source MN 620 is requested, target MN 630 sends a message to source MN 620 confirming the handover request for each candidate target PCell. At this time, the message confirming the handover request can be a response message to the handover request message and can include the handover request confirmation message. Each handover request confirmation message can include information to be sent to UE 610 to perform a Rel-18 conditional handover with candidate SCGs. For example, each handover request confirmation message can include information related to the MCG configuration for the corresponding candidate target PCell and information related to at least one SCG configuration for at least one associated prepared candidate PSCell.
[0140] In step S613, the source MN 620 sends an RRC reconfiguration message to the UE 610. The RRC reconfiguration message may include MN RRC reconfiguration. Message and SN RRC reconfiguration The source MN 620 can generate an RRC reconfiguration message that includes conditional reconfiguration. In this case, the RRC reconfiguration message can be generated based on information related to the MCG configuration and / or SCG configuration delivered via the handover request confirmation message received in step S611. For example, the handover request confirmation message received in step S611 may include RRC reconfiguration. A list of messages and associated execution conditions, and a reconfiguration for each RRC. The message may include information related to the MCG configuration. Each RRC received from at least one candidate target SN in step S611 is reconfigured. The message may include information related to the SCG configuration. In step S615, UE 610 sends an RRC reconfiguration complete message to source MN 620. UE 610 may store conditional handover with information related to the configuration of the candidate SCG received in step S613, and may respond to source MN 620 using the RRC reconfiguration complete message.
[0141] In step S617, step 7 and / or subsequent steps as defined in clause 10.19 of TS 37.340 may be performed. For example, step 7 (e.g., random access procedure) and subsequent steps of Figure 10.19.2-1 in clause 10.19 of TS 37.340 may be performed.
[0142] As described above, this disclosure presents a method and apparatus for supporting conditional handover with conditional PSCell configuration in a network system.
[0143] The target master node (MN) can receive at least one conditional handover request message for at least one candidate target PCell from the source NG-RAN node serving the UE. In this case, the target MN can decide to add at least one candidate PSCell configuration for the UE using at least one adjacent candidate target SN, and can initiate a conditional PSCell addition procedure toward the candidate target SN.
[0144] A conditional PSCell addition process toward a candidate target SN can be initiated by sending a CPA request message to the candidate target SN. The CPA request message may include an SN addition request message. The SN addition request message may include at least one of the following: a list of candidate target PCells determined for the candidate target SN from the candidate target PCells requested from the source NG-RAN node for conditional handover, or information related to the allowed number of candidate PSCell configurations. Information related to the allowed number of candidate PSCell configurations may include at least one of the following: the total number of PSCell configurations that the candidate target SN is allowed to prepare for the candidate target PCell list, or the maximum number of PSCell configurations that the candidate target SN is allowed to prepare per PCell.
[0145] Candidate target SN can receive a CPA request message from target MN to initiate a CPA process. In this case, candidate target SN can perform admission control for at least one candidate PSCell and prepare at least one candidate PSCell configuration. Here, the number of at least one candidate PSCell configuration to be prepared by candidate target SN does not exceed the total number of PSCell configurations allowed by target MN. Here, the total number of PSCell configurations allowed by MN can be the total number of allowed PSCell configurations included in the CPA request message. If the CPA request message includes a maximum number of PSCell configurations allowed per PCell, the number of candidate PSCell configurations to be prepared by candidate target SN per candidate target PCell can be limited to not exceed the maximum number of PSCell configurations allowed for each candidate target PCell.
[0146] The candidate target SN can send a response message to the target MN in response to the CPA request. The response message to the CPA request may include an SN add request confirmation message. The SN add request confirmation message may include at least one of the following: a list of all candidate PSCell configurations prepared by the candidate target SN for the UE, or information about how each prepared candidate PSCell configuration is associated with which candidate PCell in the list of candidate target PCells provided from the target MN.
[0147] Figure 7 An example of a process for receiving PSCell configuration information according to an embodiment of the present disclosure is illustrated. Figure 7 An example is given of the method executed by the first node of the target MN, which is the terminal.
[0148] Reference Figure 7 In step S701, the first node receives a first message related to a conditional handover request. The first node can receive the first message related to the conditional handover request of the terminal from the source MN of the terminal. The first message may include a conditional handover request message. The first message may be received for each candidate target PCell of the terminal for conditional handover. For example, when multiple candidate target PCells suitable for conditional handover of the terminal belong to the first node, the first node may receive a conditional handover request message for each of the multiple candidate target PCells. Each conditional handover request message for each candidate target PCell may include information related to the maximum number of conditional reconfigurations that the first node is allowed to prepare for the corresponding candidate target PCell.
[0149] In step S703, the first node sends a second message related to the SN addition request to the candidate target SNs. The first node may determine at least one candidate target SN (including the first SN) for the terminal, and may send a second message related to the SN addition request to each of the at least one candidate target SNs. The second message may be a CPA request message and may include the SN addition request message. The second message may include at least one of the following: a list of candidate target PCells determined for the corresponding candidate target SN from the candidate target PCells requested from the source MN for conditional handover, or information related to the number of allowed candidate PSCell configurations. The candidate target PCells requested from the source MN may include the PCell corresponding to the first message. The information related to the number of allowed candidate PSCell configurations may include at least one of the following: the total number of allowed candidate PSCell configurations for the list of the corresponding candidate target PCells, or the maximum number of allowed PSCell configurations per PCell. The information related to the number of allowed candidate PSCell configurations may be determined based on the maximum number of allowed conditional reconfigurations included in the first message.
[0150] In step S705, the first node receives a third message related to the SN add request confirmation. The first node can receive the third message from the candidate target SN as a response to the second message. The third message can be a response to the CPA request and may include the SN add request confirmation message. The third message may include information related to the candidate PSCell configuration prepared by the candidate target SN based on the second message. Specifically, the third message may include information related to the prepared candidate PSCell configuration corresponding to each of the candidate target PCells determined for the corresponding candidate target SN. The number of prepared candidate PSCell configurations may be limited to not exceed the allowed number of candidate PSCell configurations. The third message may also include information indicating the association between each prepared candidate PSCell configuration and the candidate target PCell. For example, the third message may also include information indicating how each prepared candidate PSCell configuration is associated with which candidate target PCell in the list of candidate target PCells provided by the first node to the corresponding candidate target SN.
[0151] According to the implementation method, the first node may include a reference. Figure 6a and Figure 6b The target MN in the described implementation. The first node can also execute references. Figure 6a and Figure 6b At least one operation of the target MN described.
[0152] Figure 8An example of a process for sending PSCell configuration information according to an embodiment of the present disclosure is illustrated. Figure 8 An example is given of a method executed by a second node that is a candidate target SN acting as a terminal.
[0153] Reference Figure 8 In step S801, the second node receives a second message related to the SN addition request. The second message is a CPA request message and may include the SN addition request message. The second message can be received from the first node, which is the target MN. The second message may include at least one of a list of candidate target PCells determined for the second node, which is the candidate target SN, or information related to the allowed number of candidate PSCell configurations. The information related to the allowed number of candidate PSCell configurations may include at least one of the total number of allowed candidate PSCell configurations for the list of corresponding candidate target PCells or the maximum number of allowed PSCell configurations per PCell.
[0154] In step S803, the second node sends a third message related to the SN addition request confirmation. The second node may send the third message to the first node, which is the target MN, as a response to the second message. The third message is a response to the CPA request and may include the SN addition request confirmation message. The third message may include information related to the prepared candidate PSCell configuration corresponding to each candidate target PCell determined by the second node as the corresponding candidate target SN. The number of prepared candidate PSCell configurations may be limited to not exceed the allowed number of candidate PSCell configurations. The third message may also include information about how each prepared candidate PSCell configuration is associated with which candidate target PCell in the list of candidate target PCells provided by the first node.
[0155] According to the implementation method, the second node may include a reference. Figure 6a and Figure 6b The candidate target SN in the described implementation. The second node can also execute reference... Figure 6a and Figure 6b At least one operation of the candidate target SN described.
[0156] Examples of the methods proposed above can also be included as one of the implementation methods of this disclosure; therefore, it is clear that they can be considered as types of proposed methods. Furthermore, the methods proposed above can be implemented independently, but can also be implemented as a combination (or merging) of some proposed methods. Rules can be defined such that the base station notifies the terminal via predefined signals (e.g., physical layer signals or higher layer signals) of information regarding whether to apply the proposed methods (or information about the rules governing the proposed methods).
[0157] This disclosure may be embodied in other specific forms without departing from the technical concept and essential features described herein. Therefore, the above detailed description should not be construed as limiting in all respects, but rather as illustrative. The scope of this disclosure should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within its scope. Furthermore, claims that are not explicitly referenced in the claims may be combined to form embodiments, or may be included as new claims by subsequent amendments.
[0158] Industrial applicability
[0159] The embodiments disclosed herein can be applied to a variety of wireless access systems. Examples of various wireless access systems include 3GPP or 3GPP2 systems.
[0160] The embodiments disclosed herein can be applied not only to the various wireless access systems described above, but also to all technical fields employing various wireless access systems. Furthermore, the proposed method can also be applied to millimeter-wave and THz communication systems using the ultra-high frequency band.
[0161] Furthermore, the embodiments disclosed herein can also be applied to various applications, such as autonomous vehicles and drones.
Claims
1. A method comprising the following steps: Receive at least one first message related to the conditional handover request of the terminal from the source master node (MN) of the terminal; Send a second message related to the SN addition request to the first auxiliary node (SN) among the candidate target auxiliary nodes used for the terminal; as well as Receive a third message related to the SN addition request from the first SN. The second message includes at least one of the following: a list of candidate target PCells determined by the source MN for the first SN from among the candidate target primary cells (PCells) in response to the conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells) configured. The third message includes information related to the candidate PSCell configuration prepared by the first SN based on the second message.
2. The method according to claim 1, wherein, The information related to the number of allowed candidate PSCell configurations includes at least one of the following: the total number of PSCell configurations allowed to be prepared by the first SN for the determined list of candidate target PCells, or the maximum number of PSCell configurations allowed to be prepared by the first SN per PCell.
3. The method according to claim 1, wherein, The total number of allowed PSCell configurations or the maximum number of allowed PSCell configurations per PCell is determined based on the maximum number of allowed conditional reconfigurations included in the first message.
4. The method according to claim 1, wherein, The third message includes at least one of the following: a candidate PSCell configuration prepared by the first SN, or information indicating the association between the prepared candidate PSCell configuration and a candidate target PCell determined for the first SN.
5. The method according to claim 4, wherein, The number of candidate PSCell configurations prepared is limited by the number of allowed candidate PSCell configurations.
6. The method according to claim 5, wherein, The number of candidate PSCell configurations prepared is limited by the total number of PSCell configurations allowed for the determined candidate target PCell list.
7. The method according to claim 5, wherein, The number of candidate PSCell configurations prepared is limited by the maximum number of PSCell configurations allowed per candidate target PCell.
8. The method according to claim 4, further comprising the following step: Based on the association between the prepared candidate PSCell configuration and the candidate target PCell determined for the first SN, at least one fourth message is sent to the source MN.
9. The method according to claim 1, wherein, The second message includes a message requesting the addition of a conditional PSCell.
10. The method according to claim 1, wherein, The step of receiving the at least one first message includes: receiving from the source MN a plurality of first messages corresponding to each of the plurality of candidate target PCells, and The candidate target PCell requested by the source MN includes the plurality of candidate target PCells.
11. A method comprising the following steps: Receive a second message related to the add request for the secondary node (SN) from the target primary node (MN) of the terminal; as well as Send a third message related to the SN addition request to the target MN. The second message includes at least one of the following: a list of candidate target PCells determined by the source MN for the first SN from among the candidate target primary cells (PCells) in response to the conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells) configured. The third message includes information related to the candidate PSCell configuration prepared by the first SN based on the second message.
12. An apparatus, the apparatus comprising: transceiver; as well as The processor is connected to the transceiver. The processor controls the transceiver to: Receive at least one first message related to the conditional handover request of the terminal from the source master node (MN) of the terminal; Send a second message related to the SN addition request to the first SN among the candidate target secondary nodes (SNs) used for the terminal; and Receive a third message related to the SN addition request from the first SN. The second message includes at least one of the following: a list of candidate target PCells determined by the source MN for the first SN from among the candidate target primary cells (PCells) in response to the conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells) configured. The third message includes information related to the candidate PSCell configuration prepared by the first SN based on the second message.
13. An apparatus, the apparatus comprising: transceiver; as well as The processor is connected to the transceiver. The processor controls the transceiver to: Receive a second message related to the add request for the secondary node (SN) from the target primary node (MN) of the terminal; and Send a third message related to the SN addition request to the target MN. The second message includes at least one of the following: a list of candidate target PCells determined by the source MN for the first SN from among the candidate target primary cells (PCells) in response to the conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells) configured. The third message includes information related to the candidate PSCell configuration prepared by the first SN based on the second message.
14. A communication device, the communication device comprising: At least one processor; as well as At least one memory, coupled to the at least one processor, stores instructions that, when executed by the at least one processor, instruct operations. The operation includes: Receive at least one first message related to the conditional handover request of the terminal from the source master node (MN) of the terminal; Send a second message related to the SN addition request to the first SN among the candidate target secondary nodes (SNs) used for the terminal; and Receive a third message related to the SN addition request from the first SN. The second message includes at least one of the following: a list of candidate target PCells determined by the source MN for the first SN from among the candidate target primary cells (PCells) in response to the conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells) configured. The third message includes information related to the candidate PSCell configuration prepared by the first SN based on the second message.
15. A non-transitory computer-readable medium storing at least one instruction. in, The at least one instruction causes the communication device to perform an operation when executed by at least one processor. The operation includes: Receive at least one first message related to the conditional handover request of the terminal from the source master node (MN) of the terminal; Send a second message related to the SN addition request to the first SN among the candidate target secondary nodes (SNs) used for the terminal; and Receive a third message related to the SN addition request from the first SN. The second message includes at least one of the following: a list of candidate target PCells determined by the source MN for the first SN from among the candidate target primary cells (PCells) in response to the conditional handover request, or information related to the number of allowed candidate primary and secondary cells (PSCells) configured. The third message includes information related to the candidate PSCell configuration prepared by the first SN based on the second message.