Method and apparatus for SRS reconfiguration for supporting positioning service of terminal in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a first base station (BS) in a wireless communication system is provided. The method includes transmitting a retrieved user equipment (UE) context request message for sounding reference signal (SRS) configuration to a second base station (BS), and receiving a requested sounding reference signal (SRS) transmission characteristic for the SRS configuration.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method and apparatus for supporting a positioning service when a user equipment (UE) is in a radio resource control (RRC) inactive state in the wireless communication system. Background Art

[0002] Fifth-generation (5G) mobile communication technology defines a wide frequency band that enables high transmission rates and new services, and is achievable not only in "sub-6 gigahertz (GHz)" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands, known as millimeter waves (mmWave), including 28 GHz and 39 GHz. Furthermore, in order to achieve transmission rates fifty times faster than 5G mobile communication technology and ultra-low latency one-tenth that of 5G mobile communication technology, the implementation of sixth-generation (6G) mobile communication technology (referred to as "Beyond 5G Systems (5GSs)") in the terahertz (THz) frequency band (e.g., the 95 GHz to 3 THz band) is being considered.

[0003] At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC) and massive machine-type communication (mMTC), standardization has been underway on the following technologies: beamforming and massive multiple-input multiple-output (MIMO) for mitigating radio wave path loss and increasing radio wave transmission range in mmWave, support for dynamic operation of parameter sets (e.g., operating multiple subcarrier spacings) and time slot formats for efficient utilization of mmWave resources, initial access technology supporting multi-beam transmission and wideband, definition and operation of bandwidth parts (BWPs), new channel coding methods (such as low-density parity-check (LDPC) codes for large-scale data transmission and polar codes for highly reliable transmission of control information), layer 2 (L2) pre-processing, and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services to be supported by 5G mobile communication technology, discussions are underway on improvements and performance enhancements to initial 5G mobile communication technology, and there is already standardization of physical layers on technologies such as Vehicle-to-Everything (V2X) for assisting driving determination of unmanned vehicles based on information about the position and status of a vehicle transmitted by the vehicle and for enhancing user convenience, New Radio Unlicensed (NR-U) designed to enable system operation in unlicensed bands to comply with various regulatory requirements, New Radio (NR) UE power saving, Non-Terrestrial Network (NTN) for UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable, and positioning.

[0005] In addition, in the field of radio interface architecture / protocols, standardization is underway on technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interoperability and integration with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and dual-active protocol stack (DAPS), and two-step random access (NR's two-step random access channel (RACH)) for simplifying the random access procedure. In terms of system architecture / services, standardization is also underway on the following: a 5G baseline architecture (e.g., a service-based architecture or service-based interface) for combining network function virtualization (NFV) and software-defined networking (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] With the commercialization of 5G mobile communication systems, the already exponentially growing number of connected devices will be connected to the communication network, and accordingly, it is expected that enhanced functionality and performance of 5G mobile communication systems and the integrated operation of connected devices will become necessary. To this end, new research is planned related to: extended reality (XR) for effectively supporting augmented reality (AR), virtual reality (VR), mixed reality (MR), etc.; improving 5G performance and reducing 5G complexity by utilizing artificial intelligence (AI) and machine learning (ML); AI service support; metaverse service support; and drone communication.

[0007] Furthermore, this evolution of 5G mobile communication systems will serve as a foundation for developing not only new waveforms for providing terahertz band coverage for 6G mobile communication technology, multi-antenna transmission technologies (such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas), metamaterial-based lenses and antennas for improving terahertz band signal coverage, high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), but also full-duplex technologies for increasing the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technologies for achieving system optimization by leveraging satellites and AI (artificial intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for implementing services at a complexity level that exceeds the operational capabilities of UEs by utilizing ultra-high-performance communication and computing resources.

[0008] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with respect to the present disclosure. Summary of the Invention

[0009] Solution to the problem

[0010] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Accordingly, one aspect of the present disclosure is to provide an apparatus and method capable of efficiently providing a service in a mobile communication system.

[0011] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0012] According to one aspect of the present disclosure, a method for processing a control signal in a wireless communication system is provided, wherein the method includes receiving a first control signal transmitted from a base station, processing the received first control signal, and transmitting a second control signal generated based on the processing to the base station.

[0013] According to another aspect of the present disclosure, a method performed by a first base station (BS) in a wireless communication system is provided. The method includes sending a retrieve user equipment (UE) context request message for sounding reference signal (SRS) configuration to a second base station (BS), and receiving a sounding reference signal (SRS) transmission characteristic requested for the SRS configuration.

[0014] According to another aspect of the present disclosure, a method performed by a second base station (BS) in a wireless communication system is provided, wherein the method includes receiving a retrieve user equipment (UE) context request message for sounding reference signal (SRS) configuration from a first base station (BS), and transmitting information for SRS configuration.

[0015] According to another aspect of the present disclosure, a first base station (BS) in a wireless communication system is provided. The first BS includes a transceiver, a memory storing one or more computer programs, and one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more computer programs include computer-executable instructions that, when executed by the one or more processors, cause the first BS to send a retrieve user equipment (UE) context request message for a sounding reference signal (SRS) configuration to a second base station (BS), and receive a sounding reference signal (SRS) transmission characteristic requested for the SRS configuration.

[0016] According to another aspect of the present disclosure, a second base station (BS) in a wireless communication system is provided. The second BS includes a transceiver, a memory storing one or more computer programs, and one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more computer programs include computer-executable instructions that, when executed by the one or more processors, cause the second BS to receive a user equipment (UE) context request message for sounding reference signal (SRS) configuration from a first base station (BS) and transmit information for SRS configuration.

[0017] According to another aspect of the present disclosure, one or more non-transitory computer-readable storage media storing one or more computer programs including computer-executable instructions are provided that, when executed by one or more processors of a first base station (BS), cause the first BS to perform operations. The operations include sending a retrieve user equipment (UE) context request message for a sounding reference signal (SRS) configuration to a second base station (BS), and receiving a requested sounding reference signal (SRS) transmission characteristic for the SRS configuration.

[0018] The disclosed embodiments provide an apparatus and method capable of efficiently providing services in a mobile communication system.

[0019] Other aspects, advantages, and salient features of the present disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the accompanying drawings, discloses various embodiments of the present disclosure.

[0020] Advantageous Effects of the Invention

[0021] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below.Accordingly, one aspect of the present disclosure is to provide an efficient communication method in a wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0023] Figure 1 The structure of a mobile communication system (or wireless communication system) for providing positioning services according to an embodiment of the present disclosure is shown;

[0024] Figure 2 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for positioning services transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure;

[0025] Figure 3is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for positioning services transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure;

[0026] Figure 4A shows an operation sequence of a base station according to an embodiment of the present disclosure;

[0027] Figure 4B shows an operation sequence of a base station according to an embodiment of the present disclosure;

[0028] Figure 5A An Xn retrieve UE context request message and information elements (IEs) included in the Xn retrieve UE context request message according to an embodiment of the present disclosure are shown;

[0029] Figure 5B An Xn retrieve UE context request message and information elements (IEs) included in the Xn retrieve UE context request message according to an embodiment of the present disclosure are shown;

[0030] Figure 6A An Xn retrieve UE context response message and information elements (IEs) included in the Xn retrieve UE context response message according to an embodiment of the present disclosure are shown;

[0031] Figure 6B An Xn retrieve UE context response message and information elements (IEs) included in the Xn retrieve UE context response message according to an embodiment of the present disclosure are shown;

[0032] Figure 6C An Xn retrieve UE context response message and information elements (IEs) included in the Xn retrieve UE context response message according to an embodiment of the present disclosure are shown;

[0033] Figure 7 illustrating an NR Positioning Protocol A (NRPPa) positioning information update message according to an embodiment of the present disclosure;

[0034] Figure 8 An Xn part UE context transfer message and information elements (IEs) included in the Xn part UE context transfer message according to an embodiment of the present disclosure are shown;

[0035] Figure 9A An Xn Partial UE Context Transfer Confirm message and information elements (IEs) included in the Xn Partial UE Context Transfer Confirm message according to an embodiment of the present disclosure are shown;

[0036] Figure 9BAn Xn Partial UE Context Transfer Confirm message and information elements (IEs) included in the Xn Partial UE Context Transfer Confirm message according to an embodiment of the present disclosure are shown;

[0037] Figure 10A The present invention illustrates an Xn UE positioning information request message, an Xn UE positioning information response message, and information elements (IEs) included in the message, which support an Xn UE positioning information request procedure according to an embodiment of the present disclosure;

[0038] Figure 10B The present invention illustrates an Xn UE positioning information request message, an Xn UE positioning information response message, and information elements (IEs) included in the message, which support an Xn UE positioning information request procedure according to an embodiment of the present disclosure;

[0039] Figure 11 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for positioning services transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure;

[0040] Figure 12 shows an operation sequence of a base station according to an embodiment of the present disclosure;

[0041] Figure 13 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for positioning services transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure;

[0042] Figure 14 shows an operation sequence of a base station according to an embodiment of the present disclosure;

[0043] Figure 15A shows an NRPPa positioning information update message, an NRPPa positioning information update request message, and information elements (IEs) included in the NRPPa message according to an embodiment of the present disclosure;

[0044] Figure 15B shows an NRPPa positioning information update message, an NRPPa positioning information update request message, and information elements (IEs) included in the NRPPa message according to an embodiment of the present disclosure;

[0045] Figure 16 shows an NRPPa positioning information request message and information elements (IEs) included in the NRPPa positioning information request message according to an embodiment of the present disclosure;

[0046] Figure 17is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for positioning services transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure;

[0047] Figure 18 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for positioning services transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure;

[0048] Figure 19 shows an operation sequence of a base station according to an embodiment of the present disclosure;

[0049] Figure 20 shows an operation sequence of a UE according to an embodiment of the present disclosure;

[0050] Figure 21A A Long Term Evolution (LTE) Positioning Protocol (LPP) message and information elements (IEs) included in the LPP message according to an embodiment of the present disclosure are shown;

[0051] Figure 21B An LTE Positioning Protocol (LPP) message and information elements (IEs) included in the LPP message according to an embodiment of the present disclosure are shown;

[0052] Figure 21C An LTE Positioning Protocol (LPP) message and information elements (IEs) included in the LPP message according to an embodiment of the present disclosure are shown;

[0053] Figure 22 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure; and

[0054] Figure 23 is a block diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure.

[0055] Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. DETAILED DESCRIPTION

[0056] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Therefore, one aspect of the present disclosure is to provide a terminal in a wireless communication system and a communication method thereof.

[0057] Mode for use in the present invention

[0058] The following description, with reference to the accompanying drawings, is provided to facilitate a fuller understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to aid understanding, but these details are to be considered merely as exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. Furthermore, descriptions of well-known functions and structures may be omitted for clarity and conciseness.

[0059] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purposes only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0060] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0061] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted or schematically shown. In addition, the size of each element does not fully reflect the actual size. In the accompanying drawings, the same or corresponding elements are provided with the same reference numerals.

[0062] The advantages and features of the present disclosure and the manner in which they are achieved will be apparent by reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but may be implemented in various different forms. The following embodiments are provided only to fully disclose the present disclosure and to inform those skilled in the art of the scope of the present disclosure, and the present disclosure is limited only by the scope of the appended claims. The terms described below are defined in consideration of the functions in the present disclosure and may vary depending on the user, the user's intention or custom. Therefore, the definition of the terms should be based on the content in the entire specification.

[0063] The following detailed description of the embodiments of the present disclosure is mainly directed to the New Radio (NR) as a radio access network and the Packet Core (5G system, 5G core network or Next Generation Core (NG Core)) as a core network, which are specified in the 5G mobile communication standard defined by the Third Generation Partnership Project (3GPP) as a mobile communication standardization group, but based on the determination of those skilled in the art, the main ideas of the present disclosure can be applied to other communication systems with similar backgrounds or channel types with some modifications without significantly departing from the scope of the present disclosure.

[0064] In the following description, for convenience, some terms and names defined in 3GPP standards (standards for 5G, NR, LTE, or similar systems) will be used. However, the present disclosure is not limited to these terms and names and can be applied in the same manner to systems conforming to other standards.

[0065] In the following description, for the sake of convenience, terms used to identify access nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are illustratively used. Therefore, the present disclosure is not limited to the terms used below, and other terms referring to subjects with equivalent technical meanings may be used.

[0066] In the following description, a base station is an entity that allocates resources to a terminal and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a base station controller, and a node on a network. A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. Of course, examples of base stations and terminals are not limited thereto. In this disclosure, "downlink (DL)" refers to the radio link via which a base station transmits signals to a terminal, and "uplink (UL)" refers to the radio link via which a terminal transmits signals to a base station.

[0067] In this document, it will be understood that each block of the flowchart diagram and the combination of blocks in the flowchart diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a device for implementing the functions specified in one or more flowchart blocks. These computer program instructions can also be stored in a computer-usable or computer-readable memory, which can instruct the computer or other programmable data processing device to act in a specific manner so that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including an instruction device that implements the functions specified in the flowchart block or multiple blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are performed on the computer or other programmable device to produce a computer-implemented process so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more flowchart blocks.

[0068] In addition, each block of the flowchart diagram may represent a module, segment or portion of code, which includes one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative embodiments, the functions marked in the blocks may not occur in order. For example, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order, depending on the functions involved.

[0069] As used in the embodiments of the present disclosure, a "unit" refers to a software element or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, the term "unit" is not always limited to software or hardware. A "unit" can be configured to be stored in an addressable storage medium or executed by one or more processors. Therefore, a "unit" includes, for example, software elements, object-oriented software elements, class elements, or task elements, processes, functions, properties, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a "unit" can be combined into a smaller number of elements or "units" or divided into a larger number of elements or "units." Furthermore, elements and "units" can be implemented as one or more central processing units (CPUs) within a playback device or secure multimedia card. Furthermore, according to some embodiments, a "unit" can include one or more processors.

[0070] In the following description, for ease of description, the present disclosure will be described using terms and names defined in the 5GS and NR standards, which are the latest of existing communication standards specified by the Third Generation Partnership Project (3GPP) group. However, the present disclosure is not limited by these terms and names and can be applied in the same manner to systems conforming to other standards. In particular, the present disclosure can be applied to 3GPP 5GS / NR (fifth-generation mobile communication standards).

[0071] The disclosed embodiments relate to providing a positioning service for a user equipment (UE) in a mobile communication system, and more particularly, may provide a method for, when providing a positioning service using an uplink sounding reference signal (SRS) transmitted by the UE even if the UE is in an RRC inactive state, requesting SRS reconfiguration from a base station where the UE is located, and then receiving SRS configuration information from the base station again, wherein the SRS reconfiguration request occurs when the UE determines that a cause of reconfiguration of uplink SRS configuration information received when the UE transitions to the RRC inactive state is such that a cell where the UE is located is changed due to the UE moving from the RRC inactive state, or the UE leaves a valid area established with the uplink sounding reference signal (SRS) configuration information.

[0072] It should be understood that the blocks in each flowchart and the combination of flowcharts can be performed by one or more computer programs comprising instructions. The entirety of one or more computer programs can be stored in a single memory device, or one or more computer programs can be divided into different parts stored in different multiple memory devices.

[0073] Any functions or operations described herein may be processed by a processor or a combination of processors. A processor or a combination of processors is a circuit that performs processing and includes, for example, an application processor (AP, e.g., a central processing unit (CPU)), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth chip, or a processor. ® Chips, Global Positioning System (GPS) chips, Near Field Communication (NFC) chips, connection chips, sensor controllers, touch controllers, fingerprint sensor controllers, display driver integrated circuits (ICs), audio CODEC chips, Universal Serial Bus (USB) controllers, camera controllers, image processing ICs, microprocessor units (MPUs), systems on chip (SoCs), integrated circuits (ICs), etc.

[0074] Figure 1 The structure of a mobile communication system (or wireless communication system) for providing a positioning service according to an embodiment of the present disclosure is shown.

[0075] refer to Figure 1 The radio access network (RAN) nodes 20 and 30 specified in the communication system architecture for providing positioning services may be mobile communication base stations connected to a core network (CN), such as a 5G core network (5GC), and may be mobile communication base stations directly connected to the access and mobility management function (AMF) 50 included in the 5GC. For example, the RAN node 30 may be a NR gNB, etc. A UE 10 may communicate with the RAN node 20 of the cell in which the UE 10 is located. Furthermore, neighboring RAN nodes 30 of the cell in which the UE 10 is located may receive uplink signals (e.g., uplink SRS signals) transmitted by the UE 10 for positioning, and the uplink signals (e.g., uplink SRS signals) transmitted by the UE 10 for positioning may be used as information for the positioning service. According to embodiments of the present disclosure, a positioning service may refer to a service for calculating the location of a UE. The RAN nodes 20 and 30 may use a base station-to-base station interface (e.g., an Xn interface) to perform inter-RAN node communication. Furthermore, the RAN nodes 20 and 30 may be respectively organized into a plurality of network devices (eg, including at least one of a central unit (CU), a distributed unit (DU), and a remote unit (RU)).

[0076] The Location Management Function (LMF) 60 is a function (or entity) of the core network for providing positioning services for calculating the location of the UE. It can be connected to the AMF 50 and communicate with the RAN nodes 20 and 30 and the UE 10 through the AMF to provide positioning services. The RAN nodes 20 and 30 and the AMF 50 of the core network can communicate using the interface between the RAN node and the core network (e.g., the NG interface). When communicating with the Location Management Function (LMF) 60 and the RAN nodes 20 and 30, the AMF 50 can use positioning-related protocols (e.g., NR Positioning Protocol A (NRPPa)), and positioning-related protocol messages (e.g., NRPPa messages) can be included in messages used in the interface (e.g., the NG interface) used for the connection between the RAN nodes 20 and 30 and the core network.

[0077] Figure 2 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for a positioning service transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure.

[0078] refer to Figure 2 When providing a positioning service using an uplink sounding reference signal (SRS) transmitted by a UE in an RRC inactive state, if the UE determines that the SRS needs to be reconfigured because the cell in which the UE is located has changed due to the UE moving from the RRC inactive state, or the UE has left a valid area established using uplink sounding reference signal (SRS) configuration information, a signal flow describing a method and signal process for requesting SRS reconfiguration from the base station in which the UE is located and then receiving SRS configuration information from the base station again is shown. According to an embodiment of the present disclosure, the valid area can be an area in which the UE can continuously use the received SRS configuration information even when the cell in which the UE is located changes.

[0079] In operation 100, the LMF 60 may perform a process of receiving information about a transmission and reception point (TRP) for a positioning service from base stations 20, 30, and 40 (e.g., NR gNB or LTE eNB), and a message required for the process of receiving information about the TRP for the positioning service may be transmitted and / or received via the AMF 50.

[0080] In operation 200 , the LMF 60 may request positioning capability information of the UE 10 via an LTE Positioning Protocol (LPP) capability transfer procedure with the UE 10 , and may receive the positioning capability information from the UE 10 .

[0081] In operation 300 , when the UE 10 is connected to the last serving base station 20 , a procedure related to uplink SRS transmission configuration may be performed, and in the procedure related to uplink SRS transmission configuration, a positioning monitoring procedure related to measuring uplink SRS may be performed.

[0082] In operation 400 , finally the serving base station 20 may determine to transition the UE 10 to the RRC inactive state, and after transitioning to the RRC inactive state, the UE 10 may move to the cell of the serving base station 30 .

[0083] In operation 510, the UE may determine, based on system information transmitted by the serving base station, based on a signal received by the base station, or based on internal operations, that the uplink SRS transmission configuration information received by the UE 10 when it previously transitioned to the RRC inactive state is invalid. In this case, the UE 10 may initiate a procedure for requesting SRS reconfiguration. Under the following criteria, the UE may determine that SRS reconfiguration is necessary because the SRS transmission configuration is invalid.

[0084] - A case where the UE selects a cell other than a cell belonging to the valid area of ​​the currently stored or used SRS configuration information (upon cell reselection to a cell that does not belong to the valid area of ​​the currently used SRS configuration).

[0085] - A case where the UE fails to measure a downlink reference signal (RS) of spatial information included in the SRS configuration information (upon measurement failure of the DL RS configured for spatial information for the SRS).

[0086] - A case where the UE fails to measure a downlink reference signal (RS) of path loss information included in SRS configuration information (upon measurement failure of the DL RS of path loss information configured for the SRS).

[0087] - A situation where the UE detects that the Timing Advance (TA) value of the SRS transmission becomes invalid (upon detection of an invalid TA for SRS Tx (i.e., inactivePosSRS-TimeAlignmentTimer expires or Reference Signal Received Power (RSRP) changes by more than inactivePosSRS-RSRP-ChangeThreshold)).

[0088] When UE 10 initiates the process for requesting SRS reconfiguration, UE 10 may transmit an RRC ResumeRequest message to UE 10's currently selected serving base station 30 (base station's cell) in operation 520. The RRC ResumeRequest message transmitted by UE 10 includes SRS resource reconfiguration request information (SRS Resource Reconfiguration Request). The SRS resource reconfiguration request information may use the cause information included in the RRC ResumeRequest message or may use separate indicator information. An example of the composition of the RRC ResumeRequest message is shown below. Of course, the present invention is not limited to this example.

[0089]

[0090] When the resumeCause value in the RRC ResumeRequest message is configured as "SRS-ResourceConfigurationRequest", the base station can recognize that the UE has initiated a corresponding RRC resumption procedure for SRS reconfiguration in the RRC_INACTIVE state.

[0091] In operation 530, upon receiving the RRC ResumeRequest message from the UE 10, the serving base station 30 may transmit an Xn Retrieve UE Context Request message requesting UE context information to the last serving base station 20 to which the UE 10 was previously connected and which has stored the UE context information. The Xn Retrieve UE Context Request message may include information indicating that the request for the UE context has been caused by an SRS resource reconfiguration request (SRS Resource Reconfiguration Request), and the SRS reconfiguration request message may use cause information included in the Xn Retrieve UE Context Request message, or may use separate indicator information.

[0092] In operation 540, the last serving base station 20 may transmit an Xn Retrieve UE Context Response message including UE context information to the serving base station 30. The Xn Retrieve UE Context Response message may include requested SRS transmission characteristic information required for SRS configuration. The last serving base station 20 may store the requested SRS transmission characteristic information received from the LMF 60 during operation 300 and may transmit the stored requested SRS transmission characteristic information to the serving base station 30 in operation 540. In operation 540, the last serving base station 20 may transmit the Xn Retrieve UE Context Response message by including the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE.

[0093] In operation 600 , the serving base station 30 may perform a path switching procedure associated with a cell change in an RRC inactive state.

[0094] In operation 710, the serving base station 30 may determine the SRS configuration information to be configured for the UE 10 based on the information received from the last serving base station 20 in operation 540. In addition, the serving base station may determine the valid area information of the SRS configuration. The valid area information of the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list.

[0095] In operation 720, the serving base station 30 may transmit an RRC message including the SRS configuration information determined in operation 710 to the UE 10, such as an RRCRelease message. The RRC message transmitted to the UE 10 in operation 720 may include at least one of the UE's SRS configuration information and an SRS configuration retention indication. In addition, the RRC message may include valid area information for the SRS configuration.

[0096] In operation 730, the serving base station 30 may transmit an NR Positioning Protocol A (NRPPa) message including the SRS configuration information determined in operation 710, such as an NRPPa Positioning Information Update message, to the LMF 60 via the AMF 50. The NRPPa message transmitted to the LMF 60 in operation 730 may include at least one of the UE's SRS configuration information and an SRS configuration maintenance indication. In addition, the NRPPa message may also include valid area information of the SRS configuration.

[0097] In operation 800, the LMF 60 may determine at least one of a base station, a cell, and a TRP to monitor (measure) an uplink SRS transmitted by the UE, and may request monitoring of the uplink SRS of the UE from each base station via the AMF 50 by using the NRPPa measurement request procedure. In addition, the LMF 60 may receive a result of measuring the uplink SRS from each base station and may calculate the location information of the UE based on the received information.

[0098] Figure 3 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for a positioning service transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure.

[0099] refer to Figure 3 , Figure 3 The signal flow process from operation 100 to operation 520 corresponds to Figure 2The signal flow process from operation 100 to operation 520 is included in FIG, and thus a detailed description will be omitted.

[0100] In operation 530, upon receiving the RRC ResumeRequest message from the UE 10, the receiving base station 30 may transmit an Xn Retrieve UE Context Request message requesting UE context information to the last serving base station 20 to which the UE 10 had previously been connected and which has stored the UE context information. The Xn Retrieve UE Context Request message may include information indicating that the request for the UE context has been caused by an SRS reconfiguration request (SRS Resource Reconfiguration Request), and the SRS reconfiguration request information may use cause information included in the Xn Retrieve UE Context Request message, or may use separate indicator information.

[0101] In operation 530, upon receiving the Xn Retrieve UE Context Request message including information requesting UE context information and information indicating that the request for UE context has been caused by an SRS reconfiguration request (SRS Resource Reconfiguration Request) from the receiving base station 30, the last serving base station 20 may determine to continue storing the context information of the UE 10 without transmitting the UE context information to the receiving base station 30.

[0102] exist Figure 3 In operation 540, the last serving base station 20 may transmit an Xn message, such as an Xn partial UE context transfer message, to the receiving base station 30, transmitting only partial UE context information of the UE. The Xn partial UE context transfer message may include requested SRS transmission characteristic information required for SRS configuration. The last serving base station 20 may store the requested SRS transmission characteristic information received from the LMF 60 during operation 300, and may transmit the stored requested SRS transmission characteristic information to the receiving base station 30 in operation 540. In operation 540, the last serving base station 20 may transmit the Xn partial UE context transfer message by including the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE.

[0103] In operation 550, the receiving base station 30 may determine the SRS configuration information to be configured for the UE 10 based on the information received from the last serving base station in operation 540. In addition, the receiving station 30 may also determine the valid area information of the SRS configuration. The valid area information of the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list.

[0104] In operation 560, the receiving base station 30 may send an Xn retrieval UE context request message to the last serving base station 20. The Xn retrieval UE context request message may include at least one of SRS configuration information and an SRS configuration maintenance indication of the UE based on the SRS configuration information, which has been determined in operation 550. In addition, valid area information of the SRS configuration may be included.

[0105] In operation 570 , the receiving base station 30 may send an Xn Retrieve UE Context Ack message to the last serving base station 20 .

[0106] Figure 3 The signaling process from operations 540 to 550, 560, and 570 may be supported by the signaling process methods of operations 545, 555, and 565. In operation 545, the last serving base station 20 may transmit an Xn message, such as an Xn UE Positioning Information Request message, to the receiving base station 30 to convey information related to the positioning of the UE. The Xn UE Positioning Information Request message may include requested SRS transmission characteristic information required for SRS configuration. The last serving base station 20 may store the requested SRS transmission characteristic information received from the LMF 60 during operation 300 and may transmit the stored requested SRS transmission characteristic information to the receiving base station 30 in operation 545. In operation 545, the last serving base station 20 may transmit an Xn Positioning Information Response message by including the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE. In operation 555, the receiving base station 30 may determine the SRS configuration information to be configured for the UE 10 based on the information received from the last serving base station in operation 545. Furthermore, the receiving base station 30 may determine the valid area information for the SRS configuration. The valid area information for the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list. In operation 565, the receiving base station 30 may send an Xn UE positioning information response message to the last serving base station 20. The Xn UE positioning information response message may include at least one of the SRS configuration information and an SRS configuration maintenance indication for the UE based on the SRS configuration information, which was determined in operation 550. The Xn UE positioning information response message may also include the valid area information for the SRS configuration.

[0107] exist Figure 3After operation 570 or operation 565, in operation 580, the last serving base station 20 may generate an RRCRelease message to be sent to the UE, and may send an Xn retrieval UE context failure message including the RRCRelease message to be sent to the UE to the receiving base station 30. The RRCRelease message to be sent to the UE includes information related to the received SRS configuration of the UE that has been received from the receiving base station 30 in operation 560 or operation 565, and may include at least one of the SRS configuration information and the SRS configuration maintenance indication of the UE. The RRCRelease message may also include valid area information of the SRS configuration.

[0108] Upon receiving the RRCRelease message received from the last serving base station 20 in operation 580, the receiving base station 30 may transmit the received RRCRelease message to the UE 10 in operation 590. In operation 590, the RRC message transmitted to the UE 10 may include at least one of the UE's SRS configuration information and an SRS configuration maintenance indication. The RRC message may also include valid area information of the SRS configuration.

[0109] In operation 600, the last serving base station 20 may send an NRPPa message to the LMF 60 via the AMF 50, the NRPPa message including the SRS configuration information received from the receiving base station 30 in operation 560 or operation 565, such as an NRPPa positioning information update message. The NRPPa positioning information update message may include at least one of the SRS configuration information of the UE and an SRS configuration maintenance indication. In addition, the NRPPa location information update message may also include valid area information for the SRS configuration.

[0110] In operation 700, the LMF 60 may determine at least one of a base station, a cell, and a TRP to monitor (measure) an uplink SRS transmitted by the UE, and may request monitoring of the uplink SRS of the UE from each base station via the AMF 50 by using the NRPPa measurement request procedure. In addition, the LMF 60 may receive a result of measuring the uplink SRS from each base station and may calculate the location information of the UE based on the received information.

[0111] Figure 4A shows an operation sequence of a base station according to an embodiment of the present disclosure, Figure 4B FIG. 1 shows an operation sequence of a base station according to an embodiment of the present disclosure. Figure 4A and Figure 4B The base station may not support the operation sequence of the base station included in Figure 4A and Figure 4BSome processes of the base station are included, and some operations may be omitted, depending on the functions supported by the base station.

[0112] Reference Figure 4A and Figure 4B In operation 100, the base station may receive an RRC ResumeRequest message including an SRS resource reconfiguration request from a UE in an RRC inactive state. In operation 110, based on the RRCResumeRequest message transmitted by the UE, it is possible to identify which base station corresponds to the last serving base station. In operation 200, when the context of the UE that has transmitted the ResumeRequest message has been stored (the base station that has received the ResumeRequest message corresponds to the last serving base station), the SRS resource configuration process may be performed together with the existing RRCResumeRequest message processing in operation 205, if necessary.

[0113] In operation 200, when another base station is identified as the last serving base station, a UE context request message (e.g., an Xn retrieve UE context request message) may be sent to the last serving base station in operation 210. The message may include a cause value indicating that the request is caused by an SRS resource reconfiguration request or separate indication information. In operation 220, a response message may be received from the last serving base station.

[0114] The type of the message received from the last serving base station in operation 220 may be determined in operation 300, and when the message received from the last serving base station does not correspond to a UE context response message (e.g., an Xn retrieve UE context response message), a partial UE context transfer message (e.g., an Xn partial UE context transfer message), or a UE positioning information request message (e.g., an Xn UE positioning information request message), a predetermined process may be performed in operation 900 according to the type of the received message.

[0115] As a result of the determination in operation 300, when the message corresponds to a UE context response message (e.g., an Xn retrieve UE context response message), it may be determined in operation 400 whether the UE context response message (e.g., the Xn retrieve UE context response message) includes positioning-related information of the UE. As a result of the determination in operation 400, when there is no positioning-related information included in the UE context response message, a process after receiving an existing UE context response message may be performed in operation 410.

[0116] As a result of the determination in operation 400, if positioning-related information is included in the UE context response message, a path switching procedure with the core network for the UE may be performed in operation 420. Furthermore, in operation 430, the base station may determine the UE's SRS configuration based on the UE's positioning-related information received from the last serving base station. In operation 430, the base station may also determine a valid area based on the UE's SRS configuration information. In operation 440, the base station may determine whether the UE's SRS configuration information determined in operation 430 is the same as the SRS configuration information currently configured for the UE. When the UE positioning-related information received from the last serving base station includes the UE's current SRS configuration information, the determination performed by the base station in operation 440 may be based on a comparison with the SRS configuration information determined in operation 430. As a result of the determination in operation 440, if it is determined that SRS configuration information different from the UE's current SRS configuration information is to be used, an RRC message (e.g., an RRCRelease message) including the SRS configuration information may be sent to the UE in operation 450. Of course, the base station may send the determined SRS configuration information (or a message including the SRS configuration information) without comparing whether the determined SRS configuration information is the same as the current UE SRS configuration information.

[0117] The RRC message (e.g., RRCRelease message) sent to the UE in operation 450 may further include valid area information of the SRS configuration information. In operation 460, the base station may send an NRPPa message (e.g., NRPPa Positioning Information Update message) including the SRS configuration information transmitted to the UE via the AMF to the LMF. The NRPPa message (e.g., NRPPa Positioning Information Update message) sent in operation 460 may further include valid area information of the SRS configuration information.

[0118] As a result of the determination in operation 440, if it is determined that the same SRS configuration information as the current SRS configuration information of the UE is to be used, an RRC message (e.g., an RRCRelease message) including at least one of the SRS configuration information and the SRS configuration retention indication may be sent to the UE in operation 470. The RRC message (e.g., an RRCRelease message) sent to the UE in operation 470 may also include valid area information for the SRS configuration information. In operation 480, the base station may send an NRPPa message (e.g., an NRPPa positioning information update message) to the LMF via the AMF, the NRPPa message including at least one of the SRS configuration information and the SRS configuration retention indication that have been sent to the UE. The NRPPa message (e.g., an NRPPa positioning information update message) sent in operation 460 may also include valid area information for the SRS configuration information.

[0119] As a result of the determination in operation 300, when the message is a partial UE context transfer message (e.g., an Xn partial UE context transfer message), it may be determined in operation 600 whether the partial UE context transfer message (e.g., the Xn partial UE context transfer message) includes positioning-related information of the UE. As a result of the determination in operation 600, when there is no positioning-related information included in the partial UE context transfer message, a process after receiving an existing partial UE context transfer message may be performed in operation 610.

[0120] As a result of the determination in operation 600, if positioning-related information is included in the partial UE context transfer message, the base station may determine the UE's SRS configuration based on the UE's positioning-related information received from the last serving base station in operation 620. In operation 620, the base station may also determine a valid area based on the UE's SRS configuration information. In operation 630, the base station may determine that the UE's SRS configuration information determined in operation 620 is the same as the SRS configuration information currently configured for the UE. When the UE positioning-related information received from the last serving base station includes the UE's current SRS configuration information, the determination performed by the base station in operation 630 may be based on a comparison with the SRS configuration information determined in operation 620. As a result of the determination in operation 630, if it is determined that SRS configuration information different from the UE's current SRS configuration information is to be used, a partial UE context transfer confirmation message (e.g., an Xn partial UE context transfer confirmation message) including the UE's SRS configuration information may be sent to the last serving base station in operation 640. Of course, the base station may send the determined SRS configuration information (or a message including the SRS configuration information) without comparing whether the determined SRS configuration information is the same as the current UE SRS configuration information.

[0121] In operation 640, the partial UE context transfer confirmation message (e.g., Xn partial UE context transfer confirmation message) sent to the last serving base station may further include valid area information for the SRS configuration information. As a result of the determination in operation 630, if it is determined that the same SRS configuration information as the current UE SRS configuration information is to be used, a partial UE context transfer confirmation message (e.g., Xn partial UE context transfer confirmation message) including at least one of the UE's SRS configuration information and an SRS configuration maintenance indication may be transmitted to the last serving base station in operation 650. The partial UE context transfer confirmation message (e.g., Xn partial UE context transfer confirmation message) sent to the last serving base station in operation 650 may further include valid area information for the SRS configuration information.

[0122] In operation 660, a UE context transfer confirmation message (e.g., an Xn UE context retrieval confirmation message) may be sent to the last serving base station. In addition, in operation 810, an Xn message including an RRCRelease message (e.g., an Xn UE context retrieval failure message) may be received from the last serving base station, and in operation 820, the RRCRelease message received from the last serving base station may be sent to the UE.

[0123] As a result of the determination in operation 300, if the message is a UE positioning information request message (e.g., an Xn UE positioning information request message), the base station may determine the UE's SRS configuration based on the UE positioning-related information from the last serving base station in operation 710. In operation 710, the base station may also determine a valid area based on the UE's SRS configuration information. In operation 720, the base station may determine whether the UE's SRS configuration information determined in operation 710 is the same as the SRS configuration information currently configured for the UE. If the UE positioning-related information received from the last serving base station includes the UE's current SRS configuration information, the determination performed by the base station in operation 720 may be based on a comparison with the SRS configuration information determined in operation 710. If, as a result of the determination in operation 720, it is determined that SRS configuration information different from the UE's current SRS configuration information is to be used, a UE positioning information response message (e.g., an Xn UE positioning information response message) including the UE's SRS configuration information may be sent to the last serving base station in operation 730. Of course, the base station may send the determined SRS configuration information (or a message including the SRS configuration information) without comparing whether the determined SRS configuration information is the same as the current UE SRS configuration information.

[0124] In operation 730, the UE positioning information response message (e.g., an Xn UE Positioning Information Response message) sent to the last serving base station may further include valid area information for the SRS configuration information. As a result of the determination in operation 720, if it is determined that the same SRS configuration information as the current UE SRS configuration information is to be used, a UE positioning information response message (e.g., an Xn UE Positioning Information Response message) including at least one of the UE's SRS configuration information and an SRS configuration retention indication may be transmitted to the last serving base station in operation 740. In operation 740, the UE positioning information response message (e.g., an Xn UE Positioning Information Response message) sent to the last serving base station may further include valid area information for the SRS configuration information. Furthermore, in operation 810, an Xn message including an RRCRelease message (e.g., an Xn Retrieve UE Context Failure message) may be received from the last serving base station, and in operation 820, the RRCRelease message received from the last serving base station may be sent to the UE.

[0125] Figure 5A An Xn retrieve UE context request message and information elements (IEs) included in the Xn retrieve UE context request message according to an embodiment of the present disclosure are shown, and Figure 5B An Xn retrieve UE context request message and information elements (IEs) included in the Xn retrieve UE context request message according to an embodiment of the present disclosure are shown.

[0126] Reference Figure 5A and Figure 5B , which can be described in Figure 2 Operation 530 or Figure 3 An example of a configuration of an Xn Retrieve UE Context Request message sent by a serving base station to a last serving base station and an information element (IE) included in the Xn Retrieve UE Context Request message used in operation 530 of . Figure 5A and 5B The IE names in are illustrative only, and other names may be used for the same functionality.

[0127] Figure 5A An example of an Xn UE context retrieval request message is shown. The Xn UE context retrieval request message may include RRC recovery cause information, and the Xn UE context retrieval request process is initiated through the RRC recovery cause information, as shown in operation 100. Figure 5B An example of the configuration of the RRC resume cause IE is shown, where, as shown in operation 110, in addition to the "rna-update" information indicating a request to change the existing RAN notification area, the RRC resume cause information may also use the "pos-SRSReconfig" information indicating a request for positioning support SRS reconfiguration for the present disclosure. Of course, as mentioned above, other indicators may be used to indicate the SRS reconfiguration request. In addition, the Xn Retrieve UE Context Request message may include the Positioning SRS Reconfiguration Request IE, which includes indication information requesting positioning support SRS reconfiguration, such as Figure 5A As shown in operation 200, an alternative method of requesting positioning support SRS reconfiguration is provided.

[0128] Figure 6A An Xn retrieve UE context response message and information elements (IEs) included in the Xn retrieve UE context response message according to an embodiment of the present disclosure are shown. Figure 6B An Xn retrieve UE context response message and information elements (IEs) included in the Xn retrieve UE context response message according to an embodiment of the present disclosure are shown, and Figure 6C An Xn retrieve UE context response message and information elements (IEs) included in the Xn retrieve UE context response message according to an embodiment of the present disclosure are shown.

[0129] Reference Figures 6A to 6C , which can be shown in Figure 2 An example of an Xn retrieve UE context response message sent by the last serving base station to the serving base station and an information element (IE) included in the Xn retrieve UE context response message used in operation 540 of . Figure 6A 、 Figure 6B and Figure 6C The IE names in are illustrative only and other names may be used for the same functionality.

[0130] Figure 6A An example of an Xn retrieve UE context response message is shown. The Xn retrieve UE context request message may include a UE context information retrieve UE context response IE, where the UE context information retrieve UE context response IE includes UE context information, as shown in operation 100. Figure 6B An example of a UE context information - retrieve UE context response IE is shown. The UE context information - retrieve UE context response IE may include a location information IE, such as Figure 6B Operation 200 is shown. Figure 6C An example of a Positioning Information IE is shown. The Positioning Information IE may include an IE that includes SRS configuration information currently configured for the UE, such as the Current SRS Configuration IE, as disclosed in the present disclosure. Figure 6C As indicated in operation 300 of .

[0131] Figure 7 An NRPPa positioning information update message and information elements (IEs) included in the NRPPa positioning information update message according to an embodiment of the present disclosure are shown.

[0132] Reference Figure 7 , which can be described in Figure 2 Operation 730 and Figure 3 An example of an NRPPa positioning information update message used in operation 600 and an information element (IE) included in the NRPPa positioning information update message, which are transmitted by the base station to the LMF via the AMF. Figure 7 The IE names included are illustrative only, and other names may be used for the same functionality.

[0133] Figure 7An example of an NRPPa positioning information update message is shown. The NRPPa positioning information update message may include UE SRS configuration information, as shown in operation 100. In addition, for the present disclosure, the NRPPa positioning information update message may include an SRS configuration maintenance indication IE, through which information indicating that the UE SRS configuration information is maintained may be transmitted, as shown in operation 200. The NRPPa positioning information update message may also include a valid area IE, which includes valid area information of the SRS configuration information, as shown in operation 300. Of course, the present disclosure is not limited to the above examples, and may only include at least one of the aforementioned information.

[0134] Figure 8 An Xn partial UE context transfer message and information elements (IEs) included in the Xn partial UE context transfer message according to an embodiment of the present disclosure are shown.

[0135] refer to Figure 8 , which can be shown in Figure 3 1 and 2. Examples of an Xn-part UE context transfer message transmitted by the last serving base station to the serving base station and information elements (IEs) included in the Xn-part UE context transfer message used in operation 540 of FIG. Figure 8 The IE names included are illustrative only, and other names may be used for the same functionality.

[0136] Figure 8 An example of an Xn partial UE context transfer message is shown. The Xn partial UE context transfer message may include a positioning information IE, as indicated in operation 100 of the present disclosure. The positioning information IE may correspond to Figure 6C An example of an IE, and may include an IE including SRS configuration information currently configured for the UE, for example, a current SRS configuration IE, such as Figure 6C As indicated in operation 300 of . Of course, the positioning information IE is not limited to the above examples, and may include only at least one of the aforementioned information.

[0137] Figure 9A An Xn Partial UE Context Transfer Confirm message and information elements (IEs) included in the Xn Partial UE Context Transfer Confirm message according to an embodiment of the present disclosure are shown, and Figure 9B An Xn Partial UE Context Transfer Confirm message and information elements (IEs) included in the Xn Partial UE Context Transfer Confirm message according to an embodiment of the present disclosure are shown.

[0138] Now refer to Figure 9A and Figure 9B , which can be shown in Figure 2Examples of an Xn partial UE context transfer confirmation message sent by a receiving base station (or serving base station) to a last serving base station and information elements (IEs) included in the Xn partial UE context transfer confirmation message used in operation 560 of . Figure 9A and 9B The IE names in are illustrative only, and other names may be used for the same functionality.

[0139] Figure 9A An example of an Xn partial UE context transfer confirmation message is shown. The Xn partial UE context transfer confirmation message may include UE SRS configuration information, as shown in operation 100. For the present disclosure, an SRS configuration retention indication IE may transmit information indicating that the UE SRS configuration information is retained, as shown in operation 200, and a valid area IE including valid area information of the SRS configuration information, as shown in operation 300. Of course, the Xn partial UE context transfer confirmation message is not limited to the above example and may include only at least one of the aforementioned information.

[0140] Figure 9B An example of an SRS configuration IE is shown. The SRS configuration IE may have the same configuration as the SRS configuration IE used by the base station to transmit SRS configuration information to the LMF. Of course, the SRS configuration IE is not limited to the above example.

[0141] Figure 10A An Xn UE positioning information request message, an Xn UE positioning information response message, and information elements (IEs) included in the Xn UE positioning information request message and the Xn UE positioning information response message to support the Xn UE positioning information request procedure according to an embodiment of the present disclosure are shown, and Figure 10B An Xn UE positioning information request message, an Xn UE positioning information response message, and information elements (IEs) included in the Xn UE positioning information request message and the Xn UE positioning information response message to support an Xn UE positioning information request procedure according to an embodiment of the present disclosure are illustrated.

[0142] Reference Figure 10A , which can be shown in Figure 3 4. Examples of an Xn UE positioning information request message sent by the last serving base station to the receiving base station (or serving base station) and information elements (IEs) included in the Xn UE positioning information request message used in operation 545 of FIG. Figure 10A The message names and IE names included in are illustrative only, and other names may be used for the same functionality.

[0143] exist Figure 10AIn the example, the Xn UE positioning information request message may include the message type IE, NG-RAN node UE XnAP ID reference IE information, etc. included in a typical Xn message. In addition, the Xn UE positioning information request message may include a requested SRS transmission characteristic IE, which needs to be referenced for SRS resource configuration in the base station, as shown in operation 110. The requested SRS transmission characteristic IE may be configured the same as the requested SRS transmission characteristic IE including the requested SRS transmission characteristic information transmitted by the LMF to the base station. The Xn UE positioning information request message may include a routing id IE including instance id information of the network function indicated in operation 120. The Xn UE positioning information request message may also include a current SRS configuration IE including the current SRS configuration information of the UE indicated in operation 130. Of course, the Xn UE positioning information request message is not limited to the above examples and may only include at least one of the aforementioned information.

[0144] Reference Figure 10B , which can be shown in Figure 3 565 , and examples of an Xn UE positioning information response message sent by the receiving base station (or serving base station) to the last serving base station and information elements (IEs) included in the Xn UE positioning information response message. Figure 10B The message names and IE names included in are illustrative only, and other names may be used for the same functionality.

[0145] exist Figure 10B In the example, the Xn UE positioning information response message may include the message type IE, NG-RAN node UE XnAP ID reference IE information, etc. included in the typical Xn message. In addition, the Xn UE positioning information response message may include the SRS configuration IE, and the base station includes the SRS resource configuration information, as shown in operation 210. The configuration of the SRS configuration IE may be the same as Figure 9B The Xn UE positioning information response message may include an SRS configuration maintenance indication IE and a valid area IE. The SRS configuration maintenance indication IE may transmit information indicating that the UE SRS configuration information is maintained, as shown in operation 220. The valid area IE includes valid area information of the SRS configuration information, as shown in operation 230. Of course, the present disclosure is not limited to the above examples, and may include only at least one of the aforementioned information.

[0146] Figure 11 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for a positioning service transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure.

[0147] refer to Figure 11 , Figure 11 The signal flow process from operation 100 to operation 520 corresponds to Figure 2 The signal flow process from operation 100 to operation 520 is included in FIG. 1 , and thus a detailed description thereof will be omitted.

[0148] In operation 530, upon receiving the RRC ResumeRequest message from the UE 10, the serving base station 30 may transmit an Xn Retrieve UE Context Request message requesting UE context information to the last serving base station 20 to which the UE 10 had previously been connected and which has stored the UE context information. Upon receiving the Xn Retrieve UE Context Request message requesting UE context information from the serving base station 30 in operation 530, the last serving base station 20 may transmit an Xn Retrieve UE Context Response message including the UE context information to the serving base station 30 in operation 540.

[0149] In operation 600 , the serving base station 30 may perform a path switching procedure associated with a cell change in an RRC inactive state.

[0150] In operation 710, the serving base station 30 may send an NRPPa message (eg, an NRPPa positioning information update message or a new NRPPa positioning information update required message) to the LMF 60 via the AMF 50, where the NRPPa message includes information requesting SRS reconfiguration.

[0151] Upon receiving the SRS reconfiguration request from the base station, the LMF 60 may transmit an NRPPa message (e.g., an NRPPa positioning information request message) including requested SRS transmission characteristic information required for SRS configuration to the serving base station 30 via the AMF 50 in operation 720. The LMF may transmit the NRPPa positioning information request message by including therein the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE.

[0152] In operation 730, the serving base station 30 may determine the SRS configuration information to be configured for the UE 10 based on the information received from the LMF 60 in operation 720. In addition, the serving base station may determine the valid area information of the SRS configuration. The valid area information of the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list.

[0153] In operation 740, the serving base station 30 may transmit an RRC message, such as an RRCRelease message, including the SRS configuration information determined in operation 730 to the UE 10. The RRC message transmitted to the UE 10 in operation 740 may include at least one of the UE's SRS configuration information and an SRS configuration retention indication. The RRC message may also include valid area information of the SRS configuration.

[0154] In operation 750, the serving base station 30 may send an NRPPa message to the LMF 60 via the AMF 50, the NRPPa message including the SRS configuration information, which is determined to have been performed in operation 730, such as an NRPPa positioning information response message or an NRPPa positioning information update message.

[0155] The NRPPa message sent to the LMF 60 in operation 750 may include at least one of the SRS configuration information of the UE and the SRS configuration maintenance indication. The NRPPa message may also include the valid area information of the SRS configuration. In the NRPPa message used in operation 750, the configuration of the NRPPa positioning information update message may be based on Figure 7 , and in the case of using the NRPPa positioning information response message, Figure 7 The SRS configuration maintenance indication IE indicated in operation 200 and the valid area IE indicated in operation 300 may be additionally included in the existing NRPPa positioning information response message.

[0156] In operation 800, the LMF 60 may determine at least one of a base station, a cell, and a TRP to monitor (measure) an uplink SRS transmitted by the UE, and may request each base station to monitor the uplink SRS of the UE by using the NRPPa measurement request procedure via the AMF 50. The LMF 60 may receive the result of measuring the uplink SRS from each base station and may calculate the location information of the UE based on the received information.

[0157] Figure 12 FIG. 1 shows an operation sequence of a base station according to an embodiment of the present disclosure. Figure 12 The base station may not be able to support the operation sequence of the base station included in Figure 12 Some processes of the base station are included, and some operations may be omitted, depending on the functions supported by the base station.

[0158] refer to Figure 12In operation 100, an RRC ResumeRequest message including an SRS resource reconfiguration request is received from a UE in an RRC inactive state. In operation 110, based on the RRC ResumeRequest message transmitted by the UE, it is possible to identify which base station corresponds to the last serving base station. In operation 200, when the context of the UE that has transmitted the ResumeRequest message has been stored (the base station that has received the ResumeRequest message corresponds to the last serving base station), the SRS resource configuration process can be performed together with the existing RRC ResumeRequest message processing in operation 205, if necessary.

[0159] As a result of the determination in operation 200, when the last serving base station is determined to be another base station, a UE context request message (e.g., an Xn retrieve UE context request message) may be sent to the last serving base station in operation 210. In operation 220, a response message may be received from the last serving base station.

[0160] In operation 300, the type of the message that has been received from the last serving base station in operation 220 is determined, and when the message received from the last serving base station is not a UE context response message (e.g., an Xn retrieve UE context response message), a predetermined process may be performed in operation 500 according to the type of the received message.

[0161] As a result of the determination in operation 300 , when the received message is determined to be the Xn retrieve UE context response message, a path switching procedure with the core network for the corresponding UE may be performed in operation 310 .

[0162] In operation 320, an NRPPa message (eg, a positioning information update message or a positioning information update required message) including information that SRS reconfiguration is required may be transmitted to the LMF via the AMF.

[0163] In operation 330, an NRPPa message (eg, an NRPPa positioning information request message) including requested SRS transmission characteristics is received from the LMF via the AMF. The NRPPa positioning information request message may include, for example, current SRS configuration information.

[0164] In operation 340, the base station may determine the SRS configuration of the UE based on the UE positioning request information received from the LMF. In operation 340, the base station may also determine a valid area of ​​the SRS configuration information of the UE.

[0165] In operation 400, the base station may determine whether the SRS configuration information of the UE determined in operation 340 is the same as the SRS configuration information currently configured for the UE. When the UE positioning-related information received from the LMF includes the current SRS configuration information of the UE, the determination performed by the base station in operation 400 may be based on a comparison with the SRS configuration information, which has been determined in operation 340.

[0166] As a result of the determination in operation 400, when it is determined to use SRS configuration information different from the current SRS configuration information of the UE, an RRC message (e.g., an RRCRelease message) including the SRS configuration information may be sent to the UE in operation 410. Of course, the base station may transmit the determined SRS configuration information (or a message including the SRS configuration information) without comparing the determined SRS configuration information with the current UE SRS configuration information to determine whether they are the same.

[0167] The RRC message (e.g., RRCRelease message) sent to the UE in operation 410 may further include valid area information of the SRS configuration information. In operation 420, the base station may send an NRPPa message (e.g., NRPPa Positioning Information Update message) to the LMF via the AMF, the NRPPa message including the SRS configuration information to be transmitted to the UE. The NRPPa message sent in operation 420 may further include valid area information of the SRS configuration information.

[0168] As a result of the determination in operation 400, when it is determined that the same SRS configuration information as the current SRS configuration information of the UE is used, an RRC message (e.g., an RRCRelease message) including at least one of the SRS configuration information and the SRS configuration maintenance indication may be sent to the UE in operation 460. The RRC message (e.g., an RRCRelease message) sent to the UE in operation 460 may also include valid area information of the SRS configuration information. In operation 470, the base station may send an NRPPa message (e.g., an NRPPa positioning information response message or an NRPPa positioning information update message) to the LMF via the AMF, the NRPPa message including at least one of the SRS configuration information and the SRS configuration maintenance indication that have been sent to the UE. The NRPPa message transmitted in operation 470 may also include valid area information of the SRS configuration information.

[0169] Figure 13 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for a positioning service transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure.

[0170] refer to Figure 13 , Figure 13 The signal flow process from operation 100 to operation 520 corresponds to Figure 2 The signal flow process from operation 100 to operation 520 is included in FIG. 1 , and thus a detailed description thereof will be omitted.

[0171] Upon receiving the RRC ResumeRequest message from the UE 10, the serving base station 30 transmits an Xn Retrieve UE Context Request message requesting UE context information to the last serving base station 20 to which the UE 10 was previously connected and which has stored the UE context information in operation 530. The Xn Retrieve UE Context Request message includes information indicating that the UE context is requested due to an SRS resource reconfiguration request, and the SRS reconfiguration request message may use cause information included in the Xn Retrieve UE Context Request message, or use separate indicator information.

[0172] In operation 540, upon receiving the Xn retrieve UE context request message requesting UE context through SRS reconfiguration request from the serving base station 30, the serving base station 20 may finally send an NRPPa message (e.g., an NRPPa positioning information update message or a new NRPPa positioning information update requirement message) including information requesting SRS reconfiguration to the LMF 60 via the AMF 50.

[0173] In operation 550 , the serving base station 20 may finally transmit an Xn retrieve UE context response message including the UE context information to the serving base station 30 .

[0174] In operation 600 , the serving base station 30 may perform a path switching procedure associated with a cell change in an RRC inactive state.

[0175] When the LMF 60 receives the SRS reconfiguration request from the base station in operation 540, the LMF 60 may transmit an NRPPa message (e.g., an NRPPa positioning information request message) to the serving base station 30 via the AMF 50 in operation 710. The NRPPa positioning information request message includes the requested SRS transmission characteristic information required for SRS configuration. The NRPPa positioning information request message may also include the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE.

[0176] In operation 720, the serving base station 30 may determine the SRS configuration information to be configured for the UE 10 based on the information received from the LMF 60 in operation 710. In addition, the serving base station 30 may determine the valid area information of the SRS configuration. The valid area information of the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list.

[0177] In operation 730, the serving base station 30 may send an RRC message (e.g., an RRCRelease message) including the SRS configuration information to the UE 10, which has been determined in operation 720. The RRC message sent to the UE 10 in operation 730 may include at least one of the UE's SRS configuration information and an SRS configuration maintenance indication. In addition, the RRC message may also include valid area information for the SRS configuration.

[0178] In operation 740, the serving base station 30 transmits an NRPPa message, for example, an NRPPa positioning information response message or an NRPPa positioning information update message, to the LMF 60 via the AMF 50, which includes the SRS configuration information, which has been determined in operation 720. The NRPPa message transmitted to the LMF 60 in operation 740 may include at least one of the SRS configuration information of the UE and an SRS configuration maintenance indication. The NRPPa message may also include valid area information of the SRS configuration. In the NRPPa message used in operation 740, the configuration of the NRPPa positioning information update message may be based on Figure 7 , and in the case of using the NRPPa positioning information response message, Figure 7 The SRS configuration maintenance indication IE indicated in operation 200 and the valid area IE indicated in operation 300 may be additionally included in the existing NRPPa positioning information response message.

[0179] In operation 800, the LMF 60 may determine at least one of a base station, a cell, and a TRP to monitor (measure) an uplink SRS transmitted by the UE, and may request each base station to monitor the uplink SRS of the UE by using the NRPPa measurement request procedure via the AMF 50. In addition, the LMF 60 may receive the result of measuring the uplink SRS from each base station and may calculate the location information of the UE based on the received information.

[0180] Figure 14 FIG. 1 shows an operation sequence of a base station according to an embodiment of the present disclosure. Figure 14 The base station may not be able to support the operation sequence of the base station included in Figure 14 Some processes of the base station are included, and some operations may be omitted, depending on the functions supported by the base station.

[0181] refer to Figure 14 In operation 100, an Xn retrieve UE context request message requesting transfer of a UE context when the UE is in an RRC inactive state may be received from another base station.

[0182] In operation 200, it may be determined whether information of a UE context for which transfer has been requested is stored.

[0183] As a result of the determination in operation 200 , when there is no stored UE context information, an existing failure procedure may be performed in operation 205 .

[0184] As a result of the determination in operation 200 , when there is stored UE context information, it may be determined in operation 300 whether an Xn retrieve UE context request message received from another base station includes SRS reconfiguration request information.

[0185] As a result of the determination in operation 300 , when the SRS reconfiguration request information is not included in the Xn Retrieve UE Context Request message, an existing UE context transfer procedure may be performed in operation 305 .

[0186] As a result of the determination in operation 300, when the Xn retrieval UE context request message includes SRS reconfiguration request information, an NRPPa message (e.g., a positioning information update message or a positioning information update required message) including an indication that SRS reconfiguration is required may be sent to the LMF via the AMF in operation 310.

[0187] In operation 320, an Xn retrieve UE context response message including the UE context information may be transmitted to the base station that has requested the UE context information.

[0188] Figure 15A An NRPPa positioning information update message, an NRPPa positioning information update required message, and information elements (IEs) included in the NRPPa message according to an embodiment of the present disclosure are shown, and Figure 15B An NRPPa positioning information update message, an NRPPa positioning information update required message, and information elements (IEs) included in the NRPPa message according to an embodiment of the present disclosure are illustrated.

[0189] Reference Figure 15A and Figure 15B , an example of an NRPPa positioning information update message and an NRPPa positioning information update required message sent by the base station to the LMF via the AMF and information elements (IEs) included in the NRPPa positioning information update message and the NRPPa positioning information update required message may be shown, and the NRPPa positioning information update message and the NRPPa positioning information update required message are used Figure 11 Operation 710 and Figure 13 Operation 540. Figure 15A and 15B The message names and IE names included in are illustrative only, and other names may be used for the same functionality.

[0190] Figure 15A An example of an NRPPa positioning information update message is shown. The NRPPa positioning information update message may additionally include an SRS reconfiguration required IE, which includes information indicating that SRS reconfiguration of the UE is required, as indicated in operation 100.

[0191] Figure 15B An example of the message required for the new NRPPa positioning information update is shown.

[0192] The NRPPa positioning information update required message may include an NRPPa transaction id IE and a message type IE included in a general NRPPa message. Further, the NRPPa positioning information update required message may additionally include an SRS reconfiguration required IE, which includes information indicating that SRS reconfiguration of the UE is required, as indicated in operation 200. Of course, the present disclosure is not limited to the above examples, and may include only at least one of the aforementioned information.

[0193] Figure 16 An NRPPa positioning information request message and information elements (IEs) included in the NRPPa positioning information request message according to an embodiment of the present disclosure are illustrated.

[0194] Reference Figure 16 , which can be described in Figure 16 Operation 720 and Figure 13 7. Example of an NRPPa positioning information request message sent by the LMF to the base station via the AMF, and information elements (IEs) included in the NRPPa positioning information request message, used in operation 710 of FIG. Figure 16 The IE names included are illustrative only, and other names may be used for the same functionality.

[0195] Figure 16 An example of an NRPPa positioning information request message is shown. The NRPPa positioning information request message may include a current SRS configuration IE including current SRS configuration information of the UE, as indicated in operation 100.

[0196] Figure 17 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for a positioning service transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure.

[0197] refer to Figure 17 , Figure 17 The signal flow process from operation 100 to operation 400 corresponds to Figure 2The signal flow process from operation 100 to operation 400 is included in FIG. 1 , and thus a detailed description thereof will be omitted.

[0198] In operation 510, the UE may determine, based on system information transmitted by the serving base station, based on a signal received by the base station, or based on internal operations, that the uplink SRS transmission configuration information received by the UE 10 when it previously transitioned to the RRC inactive state is invalid. In this case, the UE 10 may initiate a procedure to request SRS reconfiguration. Under the following criteria, the UE may determine that SRS reconfiguration is necessary because the SRS transmission configuration is invalid.

[0199] - A case where the UE selects a cell other than a cell belonging to the valid area according to the currently stored or used SRS configuration information (when the cell is reselected to a cell that does not belong to the valid area of ​​the currently used SRS configuration).

[0200] - A case where the UE fails to measure a downlink reference signal (RS) of spatial information included in the SRS configuration information (upon measurement failure of the DL RS of spatial information configured for the SRS).

[0201] - A case where the UE fails to measure a downlink reference signal (RS) of path loss information included in SRS configuration information (upon measurement failure of the DL RS of path loss information configured for the SRS).

[0202] - A situation where the UE detects that the Timing Advance (TA) value of the SRS transmission becomes invalid (upon detection of an invalid TA for SRS Tx (i.e., inactivePosSRS-TimeAlignmentTimer expires or RSRP changes by more than inactivePosSRS-RSRP-ChangeThreshold)).

[0203] When UE 10 initiates the process for requesting SRS reconfiguration, it generates an LTE Positioning Protocol (LPP) message including information requesting SRS reconfiguration. In operation 520, UE 10 transmits an RRC ResumeRequest message to the serving base station 30 (cell of the base station) currently selected by UE 10. The RRC ResumeRequest message transmitted in operation 520 may be accompanied by an LPP message including information requesting SRS reconfiguration, and thus the LPP message may be transmitted using a small data transfer (SDT) process. Alternatively, the LPP message may be transmitted after the UE enters the RRC Connected state. Figure 17 An embodiment of transmitting an LPP message through a small data transmission (SDT) processing method is shown.

[0204] In operation 530 , upon receiving the RRC ResumeRequest message from the UE 10 , the serving base station 30 transmits an Xn Retrieve UE Context Request message requesting UE context information to the last serving base station 20 to which the UE 10 has previously been connected and which has stored UE context information.

[0205] Upon receiving the Xn Retrieve UE Context Request message requesting UE context information from the serving base station 30 , the serving base station 20 may finally send an Xn Retrieve UE Context Response message including the UE context information to the serving base station 30 in operation 540 upon determining to transfer the UE context to the serving base station 30 .

[0206] In operation 600 , the serving base station 30 may perform a path switching procedure associated with a cell change in an RRC inactive state.

[0207] In operation 710 , the serving base station may transmit an NG uplink non-access stratum (NAS) transport message including the LPP message received from the UE in operation 520 to the AMF 50 , and the AMF 50 may transmit the received LPP message to the LMF 60 .

[0208] In operation 720, when the LMF 60 receives the LPP message including the SRS reconfiguration request from the UE, the LMF 60 may transmit an NRPPa message (e.g., an NRPPa positioning information request message) including the requested SRS transmission characteristic information required for SRS configuration to the serving base station 30 via the AMF 50. The NRPPa positioning information request message may also include the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE. The configuration of the NRPPa positioning information request message used in operation 720 may correspond to Figure 16 The configuration described in .

[0209] In operation 730, the serving base station 30 may determine the SRS configuration information to be configured for the UE 10 based on the information received from the LMF 60 in operation 720. In addition, the serving base station 30 may determine the valid area information of the SRS configuration. The valid area information of the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list.

[0210] In operation 740, the serving base station 30 may transmit an RRC message including the SRS configuration information determined in operation 730 to the UE 10, for example, an RRCRelease message. The RRC message transmitted to the UE 10 in operation 740 may include at least one of the UE's SRS configuration information and an SRS configuration retention indication. The RRC message may also include valid area information for the SRS configuration.

[0211] In operation 750, the serving base station 30 transmits an NRPPa message (e.g., an NRPPa positioning information response message or an NRPPa positioning information update message) including SRS configuration information to the LMF 60 via the AMF 50, wherein the SRS configuration information has been determined in operation 730. The NRPPa message transmitted to the LMF 60 in operation 750 may include at least one of the SRS configuration information of the UE and an SRS configuration maintenance indication. The NRPPa message may also include valid area information of the SRS configuration. Among the NRPPa messages used in operation 750, the configuration of the NRPPa positioning information update message may correspond to Figure 7 Message configuration included in, and in the case of using NRPPa positioning information response message, Figure 7 The SRS configuration maintenance indication IE indicated in operation 200 and the valid area IE indicated in operation 300 may be additionally included in the existing NRPPa positioning information response message. Of course, the message configuration is not limited to the above example.

[0212] In operation 800, the LMF 60 may determine at least one of a base station, a cell, and a TRP to monitor (measure) an uplink SRS transmitted by the UE, and may request each base station to monitor the uplink SRS of the UE by using the NRPPa measurement request procedure via the AMF 50. The LMF 60 may receive the result of measuring the uplink SRS from each base station and may calculate the location information of the UE based on the received information.

[0213] Figure 18 is a signal flow illustrating reconfiguration of uplink sounding reference signal (SRS) configuration information for a positioning service transmitted by a UE when the UE is in an RRC inactive state according to an embodiment of the present disclosure.

[0214] refer to Figure 18 , Figure 18 The signal flow process from operation 100 to operation 400 corresponds to Figure 2 The signal flow process from operation 100 to operation 400 is included in FIG. 1 , and thus a detailed description thereof is omitted.

[0215] In operation 510, the UE may determine, based on system information transmitted by the serving base station, based on a signal received by the base station, or based on internal operations, that the uplink SRS transmission configuration information received by the UE 10 when it previously transitioned to the RRC inactive state is invalid. In this case, the UE 10 may initiate a procedure to request SRS reconfiguration. Under the following criteria, the UE may determine that SRS reconfiguration is necessary because the SRS transmission configuration is invalid.

[0216] - A case where the UE selects a cell other than a cell belonging to the valid area according to the currently stored or used SRS configuration information (when the cell is reselected to a cell that does not belong to the valid area of ​​the currently used SRS configuration).

[0217] - A case where the UE fails to measure a downlink reference signal (RS) of spatial information included in the SRS configuration information (upon measurement failure of the DL RS of spatial information configured for the SRS).

[0218] - A case where the UE fails to measure a downlink reference signal (RS) of path loss information included in SRS configuration information (upon measurement failure of the DL RS of path loss information configured for the SRS).

[0219] - A situation where the UE detects that the Timing Advance (TA) value of the SRS transmission becomes invalid (upon detection of an invalid TA for SRS Tx (i.e., inactivePosSRS-TimeAlignmentTimer expires or RSRP changes by more than inactivePosSRS-RSRP-ChangeThreshold)).

[0220] When UE 10 initiates the process for requesting SRS reconfiguration, it generates an LTE Positioning Protocol (LPP) message including information requesting SRS reconfiguration. In operation 520, UE 10 transmits an RRC ResumeRequest message to the serving base station 30 (cell of the base station) currently selected by UE 10. The RRC ResumeRequest message transmitted in operation 520 may be accompanied by an LPP message including information requesting SRS reconfiguration, and thus the LPP message may be transmitted using a small data transfer (SDT) process. Alternatively, the LPP message may be transmitted after the UE enters the RRC Connected state. Figure 18 An embodiment of sending an LPP message through a small data transfer (SDT) processing method is shown.

[0221] In operation 530, upon receiving the RRC ResumeRequest message from the UE 10, the receiving / serving base station 30 transmits an Xn Retrieve UE Context Request message requesting UE context information to the last serving base station 20 to which the UE 10 had previously been connected and which had stored the UE context information. Upon receiving the Xn Retrieve UE Context Request message requesting UE context information from the receiving / serving base station 30, when it is determined to continue storing the UE context information without transmitting it to the receiving / serving base station 30, the last serving base station 20 may transmit an Xn Partial UE Context Transfer message including a portion of the UE context information to the receiving / serving base station 30 in operation 540.

[0222] In operation 550, the receiving / serving base station 30 may respond to the last serving base station 20 with an Xn partial UE context transfer confirmation message.

[0223] In operation 560 , the receiving / serving base station 30 may transmit an Xn RRC transmit message including the LPP message transmitted by the UE to the serving base station 20 .

[0224] In operation 570, the last serving base station 20 may send an NG uplink NAS transport message including the LPP message received from the receiving / serving base station 30 in operation 560 to the AMF 50, and the AMF 50 may transfer the received LPP message to the LMF 60.

[0225] In operation 580, when the LMF 60 receives the LPP message including the SRS reconfiguration request from the UE, the LMF 60 may send an NRPPa message (e.g., an NRPPa positioning information request message) including the requested SRS transmission characteristic information required for SRS configuration to the last serving base station 30 via the AMF 50.

[0226] In operation 590, upon receiving the NRPPa Positioning Information Request message including the requested SRS transmission characteristics information required for SRS configuration from LMF 60, the last serving base station 20 may transmit an Xn Retrieve UE Context Response message including the UE context to the receiving / serving base station 30. The Xn Retrieve UE Context Response message may include the requested SRS transmission characteristics information required for SRS configuration. In operation 590, the last serving base station 20 may also include the SRS configuration (srs-PosRRC-InactiveConfig) information currently configured for the UE in the Xn Retrieve UE Context Response message and transmit the SRS configuration information. The configuration of the Xn Retrieve UE Context Response message used in operation 590 may correspond to the configuration described in FIG. 6 .

[0227] In operation 600, the last serving base station 20 may transmit an NRPPa positioning information failure message to the LMF 60 via the AMF 50. The NRPPa positioning information failure message may include information indicating that a failure occurs due to the UE moving to another cell.

[0228] In operation 700 , the serving base station 30 may perform a path switching procedure associated with a cell change in an RRC inactive state.

[0229] In operation 810, the serving base station 30 may determine SRS configuration information to be configured for the UE 10 based on the positioning-related information received from the last serving base station 20 in operation 590. In addition, the serving base station 30 may determine valid area information for the SRS configuration. The valid area information for the SRS configuration may include a cell list, a RAN area ID list, or a tracking area ID list.

[0230] In operation 820, the serving base station 30 may transmit an RRC message including the SRS configuration information determined in operation 810 to the UE 10, for example, an RRCRelease message. The RRC message transmitted to the UE 10 in operation 820 may include at least one of the UE's SRS configuration information and an SRS configuration retention indication. The RRC message may also include valid area information for the SRS configuration.

[0231] In operation 830, the serving base station 30 may transmit an NRPPa message to the LMF 60 via the AMF 50, the NRPPa message including the SRS configuration information determined in operation 810, such as an NRPPa positioning information update message. The NRPPa message transmitted to the LMF 60 in operation 730 may include at least one of the UE's SRS configuration information and an SRS configuration maintenance indication. The NRPPa message may also include valid area information of the SRS configuration.

[0232] In operation 900, the LMF 60 may determine at least one of a base station, a cell, and a TRP to monitor (measure) an uplink SRS transmitted by the UE, and may request each base station to monitor the uplink SRS of the UE by using the NRPPa measurement request procedure via the AMF 50. The LMF 60 may receive the result of measuring the uplink SRS from each base station and may calculate the location information of the UE based on the received information.

[0233] Figure 19 The operation sequence of the base station according to the embodiment of the present disclosure is shown. Figure 19 The base station may not be able to support the operation sequence of the base station included in Figure 19Some processes of the base station are performed, and some operations may be omitted, depending on the functions supported by the base station.

[0234] refer to Figure 19 In operation 100, when the UE is in an RRC inactive state, an Xn retrieval UE context request message requesting to send a UE context may be received from another base station.

[0235] In operation 200, it may be determined whether information of a UE context for which transfer has been requested is stored.

[0236] As a result of the determination in operation 200 , when there is no stored UE context information, an existing failure procedure may be performed in operation 205 .

[0237] As a result of the determination in operation 200 , when there is stored UE context information, it may be determined in operation 300 whether an Xn retrieve UE context request message received from another base station includes SDT support request information.

[0238] As a result of the determination in operation 300 , when the SDT support request information is not included in the Xn retrieve UE context request message, an existing UE context transfer procedure may be performed in operation 305 .

[0239] As a result of the determination in operation 300 , when the SDT support request information is included in the Xn retrieve UE context request message, it may be determined in operation 310 whether to transfer the UE context to the requesting base station for SDT transmission of the UE or to continue storing the UE context.

[0240] As a result of the determination in operation 310 , when it is determined in operation 400 that the UE context is to be transferred, an existing UE context transfer procedure may be performed in operation 405 .

[0241] As a result of the determination in operation 310 , when it is determined to use the partial UE context transfer procedure instead of transferring the UE context in operation 400 , an Xn partial UE context transfer message supporting SDT transmission may be transmitted to the requesting base station in operation 410 .

[0242] In operation 420 , a NAS message transmitted by the UE may be received from the requesting base station (the NAS message may include an LPP message transmitted by the UE).

[0243] In operation 430, the NAS message transmitted by the UE may be delivered to the AMF by using the NG uplink NAS transport message.

[0244] In operation 440, an NRPPa positioning information request message including a positioning information request may be received from the LMF via the AMF. The positioning information request may include requested SRS transmission characteristic information.

[0245] In operation 450, the partial UE context transfer process may be stopped, and an Xn Retrieve UE Context Response message including UE context information may be sent to the requesting base station. The Xn Retrieve UE Context Response message may include positioning information, and the request for positioning information may include requested SRS transmission characteristics information. In addition, the positioning information may include the current SRS configuration information of the UE.

[0246] In operation 460, an NRPPa positioning information failure message including information indicating that the NRPPa positioning information process fails due to a change of a serving cell may be transmitted to the LMF via the AMF.

[0247] Figure 20 FIG. 1 shows an operation sequence of a UE according to an embodiment of the present disclosure. Figure 20 The UE operation sequence included in the UE may not be supported Figure 20 Some processes of the UE are included, and some operations may be omitted, depending on the functions supported by the UE.

[0248] refer to Figure 20 In operation 100, when it is determined that the UE is in the RRC inactive state, SRS reconfiguration for positioning service is required and a process associated therewith may be initiated. In the case of the following criteria, the UE may determine that SRS reconfiguration is necessary because the SRS transmission configuration is invalid.

[0249] - A case where the UE selects a cell other than a cell belonging to the valid area according to the currently stored or used SRS configuration information (when the cell is reselected to a cell that does not belong to the valid area of ​​the currently used SRS configuration).

[0250] - A case where the UE fails to measure a downlink reference signal (RS) of spatial information included in the SRS configuration information (upon measurement failure of the DL RS of spatial information configured for the SRS).

[0251] - A case where the UE fails to measure a downlink reference signal (RS) of path loss information included in SRS configuration information (upon measurement failure of the DL RS of path loss information configured for the SRS).

[0252] - A situation where the UE detects that the Timing Advance (TA) value of the SRS transmission becomes invalid (upon detection of an invalid TA for SRS Tx (i.e., inactivePosSRS-TimeAlignmentTimer expires or RSRP changes by more than inactivePosSRS-RSRP-ChangeThreshold)).

[0253] In operation 200 , it may be determined whether there is a currently connected LTE Positioning Protocol (LPP) session.

[0254] When there is a currently connected LTE Positioning Protocol (LPP) session in operation 200 , an LPP message including SRS reconfiguration request information may be generated in operation 310 , and a procedure for transmitting the LPP message to a base station may be initiated in operation 320 .

[0255] When there is no currently connected LTE Positioning Protocol (LPP) session in operation 200 , an RRC ResumeRequest message including SRS reconfiguration request information may be generated in operation 310 , and a procedure for transmitting the RRC ResumeRequest message to the base station may be initiated in operation 320 .

[0256] Figure 21A shows an LTE Positioning Protocol (LPP) message and a configuration of an information element (IE) contained in the LPP message according to an embodiment of the present disclosure, Figure 21B An LTE Positioning Protocol (LPP) message and a configuration of an information element (IE) contained in the LPP message according to an embodiment of the present disclosure are shown, and Figure 21C An LTE Positioning Protocol (LPP) message and a configuration of an information element (IE) included in the LPP message according to an embodiment of the present disclosure are shown.

[0257] refer to Figure 21A 、 Figure 21B and Figure 21C , which can be described in Figure 17 Operation 520 and Figure 18 An example of an LPP message that the UE sends to the LMF to request SRS reconfiguration and an information element (IE) included in the LPP message used in operation 520. Figures 21A to 21C The IE names in are illustrative only, and other names may be used for the same functionality.

[0258] Figure 21AAn example of a new LPP RequestSRS-Config message used by the UE to request SRS reconfiguration from the LMF is shown. The new LPP RequestSRS-Config message may be configured to include a RequestSRS-Config message with updateSRS-Config added thereto, as shown in operation 110, and allow updateSRS-Config to include only "true" information. In addition, in another method, as shown in operation 120, an updateSRS-Config IE may be added to the RequestSRS-Config message, and the updateSRS-Config IE may include information about the cause of the SRS reconfiguration request. The cause of the SRS reconfiguration request included in the updateSRS-Config IE may include one of the following information: cell change ('CellChange'), downlink reference signal (RS) measurement failure of spatial information ('Spatial'), and downlink reference signal (RS) measurement failure of path loss information ('Pathloss').

[0259] Figure 21B An example of an NR-Multi-RTT-RequestAssistanceData IE obtained by adding information for requesting SRS reconfiguration from the LMF to the NR-Multi-RTT-RequestAssistanceData IE included in an existing message sent by the UE to the LMF is shown. The example of the NR-Multi-RTT-RequestAssistanceData IE can be configured to include the NR-Multi-RTT-RequestAssistanceData IE added with the updateSRS-Config IE, as shown in operation 210, and to allow the updateSRS-Config IE to include only "true" information. In another method, the NR-Multi-RTT-RequestAssistanceData IE can be added with the updateSRS-Config IE, as shown in operation 220, and the updateSRS-Config IE can include information about the reason for the SRS reconfiguration request. The cause of the SRS reconfiguration request included in the updateSRS-Config IE may include one of the following information: cell change ('CellChange'), downlink reference signal (RS) measurement failure of spatial information ('Spatial'), and downlink reference signal (RS) measurement failure of path loss information ('Pathloss').

[0260] Figure 21C An example of a CommonIEsAbort IE obtained by adding information for requesting SRS reconfiguration from the LMF to the CommonIEsAbort IE included in an existing message sent by the UE to the LMF is shown. In the present disclosure, as indicated in operation 310, stopSRS-Transmission may be added to abortCause included in the CommonIEsAbort IE. When the UE configures abortCause as stopSRS transmission, the UE transmits information indicating the stop of SRS transmission for positioning services to the LMF, thereby allowing the LMF to initiate a procedure for SRS reconfiguration.

[0261] Figure 22 The structure of a base station according to an embodiment of the present disclosure is shown.

[0262] Reference Figure 22 , the base station of the present disclosure may include a processor 2220, a transceiver 2200, and a memory 2210. However, the elements of the base station are not limited to the above examples. For example, the base station may include more or fewer elements than the above elements. In addition, the processor 2220, the transceiver 2200, and the memory 2210 may be implemented in the form of a single chip. In addition, a base station may be separately organized into multiple network devices, such as a central unit (CU), a distributed unit (DU), and a remote unit (RU).

[0263] According to an embodiment of the present disclosure, the processor 2220 may control a series of processes that the base station may perform according to the above-described embodiments of the present disclosure. For example, the processor 2220 may control elements of the base station to perform an SRS reconfiguration method to support positioning services for terminals according to the above-described embodiments. The processor 2220 may control elements of the base station to perform the above-described embodiments of the present disclosure by executing programs stored in the memory 2210. Furthermore, the processor 2220 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

[0264] According to an embodiment of the present disclosure, transceiver 2200 can transmit or receive signals to or from a network entity, another base station, or a terminal. The signals transmitted to or received from the network entity, another base station, or a terminal may include control information and data. Transceiver 2200 may include a radio frequency (RF) transmitter that upconverts and amplifies the frequency of transmitted signals, and an RF receiver that performs low-noise amplification and downconverts the frequency of received signals. However, this is merely an example of transceiver 2200, and the components of transceiver 2200 are not limited to RF transmitters and RF receivers. In addition, transceiver 2200 may receive signals via a wireless channel and output the received signals to processor 2220, and may also transmit signals output from processor 2220 via a wireless channel.

[0265] According to an embodiment of the present disclosure, the memory 2210 may store programs and data required for the operation of the base station. Furthermore, the memory 2210 may store control information or data included in signals transmitted and received by the base station. The memory 2210 may include a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a compact disc read-only memory (CD-ROM), and a digital versatile disc (DVD), or a combination of these storage media. Furthermore, multiple memories 2210 may exist. Furthermore, according to an embodiment, the memory 2210 may store a program for executing the SRS reconfiguration method to support positioning services for a terminal.

[0266] Figure 23 The structure of a terminal according to an embodiment of the present disclosure is shown.

[0267] refer to Figure 23 , the terminal of the present disclosure may include a processor 2320, a transceiver 2300, and a memory 2310. However, the elements of the terminal are not limited to the above examples. As an example, the terminal may include more or fewer elements than the above elements. In addition, the processor 2320, the transceiver 2300, and the memory 2310 may be implemented in the form of a single chip. In addition, the processor 2320, the transceiver 2300, and the memory 2310 may be implemented as a single chip.

[0268] According to an embodiment of the present disclosure, the processor 2320 may control a series of processes that the terminal may perform according to the above-described embodiments of the present disclosure. For example, the processor 2320 may control components of the terminal to perform an SRS reconfiguration method to support positioning services for the terminal according to the above-described embodiments. The processor 2320 may control components of the terminal to perform the above-described embodiments of the present disclosure by executing a program stored in the memory 2310. Furthermore, the processor 2320 may be an application processor (AP), a communication processor (CP), a circuit, a dedicated circuit, or at least one processor.

[0269] According to an embodiment of the present disclosure, the transceiver 2300 can transmit or receive signals to or from a network entity, another terminal, or a base station. The signals transmitted to or received from the network entity, another terminal, or a base station may include control information and data. The transceiver 2300 may include an RF transmitter that up-converts and amplifies the frequency of the transmitted signal, and an RF receiver that performs low-noise amplification and down-conversion of the received signal. However, this is merely an example of the transceiver 2300, and the elements of the transceiver 2300 are not limited to an RF transmitter and an RF receiver. In addition, the transceiver 2300 may receive signals via a wireless channel and output the received signals to the processor 2320, and may transmit signals output from the processor 2320 via a wireless channel.

[0270] According to an embodiment of the present disclosure, the memory 2310 may store programs and data required for the operation of the terminal. In addition, the memory 2310 may store control information or data included in signals sent and received by the terminal. The memory 2310 may include a storage medium such as ROM, RAM, hard disk, CD-ROM, and DVD, or a combination of storage media. In addition, there may be multiple memories 2310. In addition, according to an embodiment, the memory 2310 may store a program for executing the SRS reconfiguration method to support the above-mentioned positioning service for the terminal.

[0271] The methods according to various embodiments described in the claims or specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0272] When the method is implemented via software, a computer-readable storage medium may be provided for storing one or more programs (software modules). The one or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. At least one program may include instructions that cause the electronic device to perform the method according to the various embodiments of the present disclosure as defined in the appended claims and / or disclosed herein.

[0273] Programs (software modules or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disk-ROMs (CD-ROMs), digital versatile disks (DVDs) or other types of optical storage devices, or magnetic tape cassettes. Alternatively, any combination of some or all of these can form the memory in which the program is stored. Furthermore, multiple such memories can be included in an electronic device.

[0274] Alternatively, the program may be stored in an attachable storage device that can be accessed by the electronic device via a communication network such as the Internet, an intranet, a local area network (LAN), a wide area LAN (WLAN), and a storage area network (SAN), or a combination thereof. Such a storage device can access the electronic device via an external port. Furthermore, a separate storage device on a communication network can access the portable electronic device.

[0275] In the above detailed embodiments of the present disclosure, the elements included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiment presented. However, for ease of description, the singular form or plural form is appropriately selected for the situation presented, and the present disclosure is not limited to elements expressed in the singular or plural. Therefore, an element expressed in the plural may also include a single element, or an element expressed in the singular may also include multiple elements.

[0276] It should be understood that various embodiments of the present disclosure according to the claims and description in the specification can be realized in the form of hardware, software, or a combination of hardware and software.

[0277] Any such software may be stored in a non-transitory computer-readable storage medium that stores one or more computer programs (software modules) comprising computer-executable instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform the methods of the present disclosure.

[0278] Any such software may be stored in the form of volatile or non-volatile memory, such as a storage device like a read-only memory (ROM), whether erasable or rewritable, or in the form of a memory, such as a random access memory (RAM), a memory chip, device, or integrated circuit, or on an optically or magnetically readable medium, such as a compact disc (CD), a digital versatile disc (DVD), a magnetic disk, or a magnetic tape. It should be understood that the storage device and the storage medium are various embodiments of non-transitory machine-readable storage devices suitable for storing one or more computer programs comprising instructions that, when executed, implement various embodiments of the present disclosure. Accordingly, various embodiments provide a program comprising code for implementing an apparatus or method as claimed in any of the claims of this specification, as well as a non-transitory machine-readable storage device storing such a program.

[0279] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a first base station (BS) in a wireless communication system, the method comprising: sending a retrieve user equipment (UE) context request message for a sounding reference signal (SRS) configuration to a second base station (BS); and Requested sounding reference signal (SRS) transmission characteristics for the SRS configuration are received.

2. The method according to claim 1, in, The requested SRS transmission characteristics are received from the second BS via a partial UE context transfer message, and The partial UE context transmission message includes partial UE context information used for positioning, and the partial UE context information includes requested SRS transmission characteristics.

3. The method according to claim 2, further comprising: A partial UE context transfer confirmation message including the SRS configuration is sent to the second BS.

4. The method according to claim 1, wherein The requested SRS transmission characteristics are received from the Location Management Function (LMF).

5. A method performed by a second base station (BS) in a wireless communication system, the method comprising: receiving a retrieve user equipment (UE) context request message for a sounding reference signal (SRS) configuration from a first base station (BS); and Information for the SRS configuration is sent.

6. The method according to claim 5, in, Information for the SRS configuration is sent to the first BS via a partial UE context transfer message, The information used for the SRS configuration includes requested SRS transmission characteristics, and The partial UE context transmission message includes partial UE context information used for positioning, and the partial UE context information includes requested SRS transmission characteristics.

7. The method according to claim 6, further comprising: A partial UE context transfer confirm message including the SRS configuration is received from the first BS.

8. The method according to claim 5, wherein The information for the SRS configuration is sent to the Location Management Function (LMF) through the Access and Mobility Management Function (AMF), and The information used for the SRS configuration includes an indication used for the SRS configuration.

9. A first base station (BS) in a wireless communication system, the first BS comprising: transceiver; and a processor coupled to the transceiver and configured to: sending a retrieve user equipment (UE) context request message for a sounding reference signal (SRS) configuration to a second base station (BS); and A sounding reference signal (SRS) transmission characteristic for the request is received.

10. The first BS according to claim 9, in, The requested SRS transmission characteristics are received from the second BS via a partial UE context transfer message, The partial UE context transmission message includes partial UE context information used for positioning, and the partial UE context information includes requested SRS transmission characteristics.

11. The first BS according to claim 10, wherein the processor is further configured to: A partial UE context transfer confirmation message including the SRS configuration is sent to the second BS.

12. The first BS according to claim 9, wherein: The requested SRS transmission characteristics are received from the Location Management Function (LMF).

13. A second base station (BS) in a wireless communication system, the second BS comprising: transceiver; and a processor coupled to the transceiver and configured to: receiving a retrieve user equipment (UE) context request message for a sounding reference signal (SRS) configuration from a first base station (BS); and Information for the SRS configuration is sent.

14. The second BS according to claim 13, in, The information for the SRS configuration is sent to the first BS through a partial UE context transfer message, The information used for the SRS configuration includes requested SRS transmission characteristics, and The partial UE context transmission message includes partial UE context information used for positioning, and the partial UE context information includes requested SRS transmission characteristics.

15. The second BS according to claim 14, wherein the processor is further configured to: A partial UE context transfer confirm message including the SRS configuration is received from the first BS.

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