Method and device for configuring sounding reference signal in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates than a 4G communication system, such as LTE. A method performed by a terminal of a wireless communication system according to embodiments of the present disclosure comprises the steps of: receiving a list of pieces of configuration information related to a sounding reference signal (SRS) in a radio resource control (RRC) inactive state; transmitting a first message for an RRC resume request to a base station; receiving a second message for RRC release from the base station; and applying configuration information, included in the list, corresponding to a validity area including the current cell of a terminal on the basis of the reception of the second message.

Description

Method and device for setting a sounding reference signal in a wireless communication system

[0001] The present disclosure relates to the operation of a terminal and a base station in a wireless communication system. More specifically, the present disclosure relates to a method and device for providing a location estimation service for an inactive terminal in a wireless communication system.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] The present disclosure proposes a method for efficiently establishing a sounding reference signal (SRS). Furthermore, the present disclosure proposes a method for establishing sounding reference signal transmission by a terminal, enabling more efficient estimation of the location of an inactive terminal in a wireless communication system.

[0009] A method performed by a terminal of a wireless communication system according to embodiments of the present disclosure includes the steps of receiving a list of configuration information related to a sounding reference signal (SRS) in an RRC (radio resource control) inactive state, transmitting a first message for requesting RRC resumption to a base station, receiving a second message for RRC release from the base station, and applying configuration information corresponding to a validity area including a current cell of the terminal among the list based on reception of the second message.

[0010] In addition, a method performed by a first base station of a wireless communication system according to embodiments of the present disclosure includes the steps of receiving a first message for a radio resource control (RRC) resumption request from a terminal, transmitting a second message for requesting CONTEXT of the terminal to a second base station that is a last serving base station of the terminal, receiving a third message including CONTEXT of the terminal from the second base station, and transmitting a fourth message for RRC release to the terminal.

[0011] The method and device according to embodiments of the present disclosure can set up sounding reference signal transmission of a terminal so as to efficiently estimate the location of an inactive terminal in a wireless communication system.

[0012] The purpose, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings.

[0013] FIG. 1 is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0014] FIG. 2 is a diagram illustrating a network structure according to an embodiment of the present disclosure.

[0015] FIG. 3 is a diagram illustrating a process for setting up SRS (Sounding Reference Signal) resources of a terminal according to an embodiment of the present disclosure.

[0016] FIG. 4 is a diagram illustrating a scenario in which a terminal transmits SRS for location estimation in an RRC_INACTIVE state according to an embodiment of the present disclosure.

[0017] FIG. 5 is a diagram illustrating a procedure in which a terminal receives SRS preset information in an RRC_CONNECTED state and transmits one of them after activating it in an RRC_INACTIVE state according to an embodiment of the present disclosure.

[0018] FIG. 6 is a diagram illustrating a procedure for a base station to generate SRS configuration information usable by a terminal in an RRC_INACTIVE state in advance according to an embodiment of the present disclosure.

[0019] FIG. 7 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0020] FIG. 8 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0021] FIG. 9 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0022] FIG. 10 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0023] The operating principles of the present disclosure will be described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined in consideration of their functions in the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents throughout this specification. Embodiments of the present invention will be described below with reference to the attached drawings.

[0024] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0025] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The embodiments are provided solely to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined solely by the scope of the claims.

[0026] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0027] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0028] Here, the term '~ part' used in the present embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium and may be configured to play one or more processors. Therefore, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ parts' may be combined into a smaller number of components and '~ parts' or further separated into additional components and '~ parts'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~part' may include one or more processors.

[0029] In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0030] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and terms referring to various identification information are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0031] For convenience of explanation, this disclosure uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP) LTE standard. However, this disclosure is not limited by these terms and names and can be equally applied to systems conforming to other standards. In this disclosure, the term "eNB" may be used interchangeably with "gNB" for convenience of explanation. In other words, a base station described as an eNB may also represent a gNB.

[0032] Hereinafter, a base station is an entity that performs resource allocation for a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. Of course, the examples are not limited thereto.

[0033] Furthermore, while the embodiments of the present disclosure are described below using LTE, LTE-A, LTE Pro, or 5G (or NR, next-generation mobile communication) systems as examples, the embodiments of the present disclosure may also be applied to other communication systems with similar technical backgrounds or channel types. Furthermore, the embodiments of the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0034] In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described with reference to the attached drawings.

[0035] FIG. 1 is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0036] Referring to FIG. 1, as illustrated, a wireless access network of a next-generation mobile communication system (hereinafter referred to as NR or 5G) may include a next-generation base station (New Radio Node B, hereinafter referred to as NR NB, gNB, NR gNB or NR base station) (110) and an NR CN (105, New Radio Core Network). Of course, the present invention is not limited to the example, and the wireless access network of the next-generation mobile communication system may include more entities. A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (115) may access an external network through the NR gNB (110) and the NR CN (105).

[0037] In Fig. 1, the NR gNB (110) can correspond to an eNB (Evolved Node B) of an existing LTE system. The NR gNB (110) is connected to an NR UE (115) through a wireless channel (120) and can provide a service superior to that of an existing Node B. In the next-generation mobile communication system, since all user traffic is provided through a shared channel, a device that collects status information such as buffer status, available transmission power status, and channel status of UEs and performs scheduling is required, and the NR gNB (110) can be in charge of this. One NR gNB (110) can control multiple cells.

[0038] According to one embodiment of the present disclosure, the next-generation mobile communication system may have a bandwidth greater than the existing maximum bandwidth in order to implement ultra-high-speed data transmission compared to the LTE system, and may provide additional beamforming technology using Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology. In addition, the next-generation mobile communication system may use Adaptive Modulation & Coding (AMC) that determines a modulation scheme and a channel coding rate according to the channel condition of the terminal. The NR CN (105) may perform functions such as mobility support, bearer setup, and QoS setup. The NR CN (105) is a device that is responsible for various control functions as well as mobility management functions for the terminal, and may be connected to multiple base stations. In addition, the next-generation mobile communication system may also be interoperable with the existing LTE system, and the NR CN (105) may be connected to the MME (125) through a network interface. MME can be connected to an existing base station, eNB (130).

[0039] FIG. 2 is a diagram illustrating a network structure according to an embodiment of the present disclosure.

[0040] Specifically, FIG. 2 is a diagram illustrating a network structure for providing terminal location estimation services in a next-generation mobile communication system according to one embodiment of the present disclosure. The term "terminal location estimation services" may be used interchangeably with the term "LCS" hereinafter.

[0041] Referring to FIG. 2, a network for providing LCS in a next-generation mobile communication system may be composed of a terminal (201), a base station (NG-RAN Node) (202), an AMF (Access and Mobility Function) (203), and an LMF (Location Management Function) (204). At this time, the user terminal (201) may communicate with the LMF (204) through the base station (202) and the AMF (203), and exchange information necessary for estimating the location of the terminal. The AMF (203) and the LMF (204) may be referred to as a single core network entity. To provide LCS, each entity may perform, for example, the following roles:

[0042] The terminal (UE) (201) can measure a wireless signal required for estimating the location of the terminal and transmit the measurement result to the LMF (204).

[0043] The base station (202) can transmit a downlink wireless signal required for estimating the location of a terminal and measure an uplink wireless signal transmitted by a target terminal.

[0044] After receiving an LCS Request message from an LCS requester, the AMF (203) can request (or instruct) provision of a location provision service for the terminal by transmitting the LCS Request message to the LMF (204). After the LMF (204) processes the LCS (or location estimation) request, it transmits (or responds) a response message regarding the location estimation result of the terminal to the AMF (203), and the AMF (203) that receives the response message (or response) can transmit the location estimation result of the terminal to the LCS requester.

[0045] The LMF (204) may include a device that receives (or receives and processes) an LCS Request message from the AMF (203), and may control the overall process required for estimating the position of the terminal. For estimating the position of the terminal, the LMF (204) may provide the terminal (201) with auxiliary information required for position estimation and signal measurement and obtain (or receive) the resulting value. At this time, the LTE Positioning Protocol (LPP) may be used as a protocol for data exchange. The LPP may define a message standard used between the terminal (201) and the LMF (204) for position estimation service. In addition, the LMF (204) may exchange, with the base station (202), downlink reference signal (Positioning Reference Signal, hereinafter referred to as PRS) configuration information and sounding reference signal (Sounding Reference Signal, hereinafter referred to as SRS) measurement results to be used for position estimation. At this time, NRPPa (NR Positioning Protocol A) can be used as a protocol for data exchange, and NRPPa can define a message standard used between the base station (202) and the LMF (204).

[0046] FIG. 3 is a diagram illustrating a process for setting up SRS (Sounding Reference Signal) resources of a terminal according to an embodiment of the present disclosure.

[0047] Referring to FIG. 3, a procedure is illustrated for setting up SRS (Sounding Reference Signal) transmission required for UE (301) to perform at least one operation among UL positioning method or DL+UL positioning method by LMF (304). The steps illustrated in FIG. 3 are not necessarily all included depending on the settings and / or definitions in the system, and some steps may be omitted.

[0048] The UL positioning method can refer to a method for estimating the location of a terminal based on an uplink signal transmitted by the terminal. For example, this method can include a method in which the terminal transmits an SRS signal via uplink, and the gNB / TRP (transmission reception point) that receives (or measures) the SRS signal transmitted by the terminal estimates the terminal's location based on SRS measurement information (or measurement result value) acquired.

[0049] The DL+UL positioning method can refer to a method of estimating the position of a terminal based on a downlink signal transmitted by a gNB / TRP and an uplink signal transmitted by a terminal. For example, the gNB / TRP can transmit a Positioning Reference Signal (PRS) via downlink. A terminal that receives the PRS transmitted by the gNB / TRP can obtain PRS measurement information (or a measured result value). For example, a terminal transmits an SRS signal via uplink, and a gNB / TRP that receives (or measures) the SRS signal transmitted by the terminal can obtain SRS measurement information (or a measured result value). Thereafter, the position of the terminal can be estimated by using the PRS measurement information (or measured result value) measured by the terminal and the SRS measurement information (or measured result value) measured by the gNB / TRP together.

[0050] Therefore, in order to estimate the location of a terminal using at least one of the UL positioning method or the UL+DL positioning method, a procedure for configuring the terminal to transmit SRS must be performed. The procedures performed at each step are described below.

[0051] In step 305, the LMF (304) can exchange NRPPa TRP configuration information with the Serving gNB / TRP (302) and the Neighbor gNB / TRP (303). (NRPPa TRP Configuration Information Exchange)

[0052] The LMF (304) can obtain information necessary for performing the UL positioning method from the Serving gNB / TRP (302) and the Neighbor gNB / TRP (303). The information necessary for performing the UL positioning method may include at least one of NR cell information, PRS configuration, Spatial Direction information, and location information.

[0053] At step 310, capability information of the terminal can be exchanged between the LMF (304) and the UE (301). (LPP Capability Transfer)

[0054] LMF (304) can request terminal capability information related to location estimation from UE (302) and receive a response.

[0055] At step 315, the LMF (304) may transmit an NRPPa positioning information request message to the Serving gNB / TRP (302). (NRPPa POSITIONING INFORMATION REQEST)

[0056] The NRPPa positioning information request message transmitted by the LMF (304) may include information for requesting the Serving gNB / TRP (302) to determine the SRS transmission resource configuration of the UE required for UL positioning based on information previously collected by the LMF (e.g., location information of adjacent TRPs, existing location information of the UE, SSB / PRS transmission information of the TRPs, etc.). The NRPPa positioning information request message may include information on at least one of the number of required SRS resources, periodicity, pathloss reference, and spatial relation.

[0057] At step 320, the Serving gNB / TRP (302) can finally determine the SRS resources for the UE to transmit the SRS. (gNB Determines UL SRS Resources)

[0058] After the Serving gNB / TRP (302) receives the NRPPapositioning information request message from the LMF (304), it can finally determine the SRS resources to be set for the UE based on the received message.

[0059] In step 325, the Serving gNB / TRP (302) can transmit the SRS resource configuration information (or SRS resource transmission configuration information, UE SRS configuration) determined in step 320 to the UE (301). (UE SRS configuration)

[0060] Serving gNB / TRP (302) can transmit SRS resource configuration information to UE (301) through RRC signaling.

[0061] At step 330, the Serving gNB / TRP (302) may transmit an NRPPa positioning information response message to the LMF (304). (NRPPa POSITIONING INFORMATION RESPONSE)

[0062] The NRPPa positioning information response message transmitted by the Serving gNB / TRP (302) can be used to transmit SRS resource configuration information (e.g., time / frequency axis position of SRS resources, period, spatial relation information, etc.) finally transmitted to the UE (301) by the Serving gNB / TRP (302) in step 325 to the LMF.

[0063] At step 335, the LMF (304) may transmit an NRPPaPOSITIONING ACTIVATION request message to the Serving gNB / TRP (302). (NRPPa POSITIONING ACTIVATION REQUEST)

[0064] The NRPPa POSITIONING ACTIVATION request message may be used by the LMF (304) to request the Serving gNB / TRP (302) to activate SRS transmission of the UE (301) when the UE (302) is configured to transmit semi-persistent SRS or aperiodic SRS.

[0065] At step 340, the Serving gNB / TRP (302) may be configured to activate SRS transmission to the UE (301). (Activate UE SRS transmission)

[0066] The process may include a Serving gNB / TRP (302) receiving the NRPPa POSITIONING ACTIVATION REQUEST message instructing the UE (340) to activate SRS through MAC CE or DCI.

[0067] At step 345, the Serving gNB / TRP (302) may transmit an NRPPa POSITIONING ACTIVATION RESPONSE message to the UE (301). (NRPPA POSITIONING ACTIVATION RESPONSE)

[0068] The NRPPa POSITIONING ACTIVATION RESPONSE message is a response to the NRPPa POSITIONING ACTIVATION REQUEST message and can be used by the Serving gNB / TRP (302) to convey information about whether SRS activation is complete (or whether SRS activation is complete) to the LMF (304).

[0069] At step 355, LMF (304) may transmit an NRPPa MEASUREMENT REQUEST message. (NRPPa MEASUREMENT REQUEST)

[0070] The NRPPa MEASUREMENT REQUEST message may be used by the LMF (304) to request SRS measurement and result reporting transmitted by the UE to the Serving gNB / TRP (302) and the Neighboring gNB / TRP (303). At this time, the NRPPa MEASUREMENT REQUEST message may also include SRS resource information set for the UE (301).

[0071] At step 360, the Serving gNB / TRP (302) and the Neighboring gNB / TRP (303) can measure the SRS transmitted by the UE (301). (UL SRS Measurements)

[0072] The Serving gNB / TRP (302) and Neighboring gNB / TRP (303) that have received a request for SRS measurement from the LMF (304) through the NRPPa MEASUREMENT REQUEST message can measure the SRS transmitted by the UE (301) based on the SRS configuration information included in the NRPPa MEASUREMENT REQUEST message.

[0073] At step 365, the Serving gNB / TRP (302) and the Neighboring gNB / TRP (303) may transmit an NRPPa MEASUREMENT RESPONSE message to the LMF (304). (NRPPa MEASUREMENT RESPONSE)

[0074] The NRPPa MEAUREMENT RESPONSE message can be used by the Serving gNB / TRP (302) and the Neighboring gNB / TRP (303) that received a request for SRS measurement from the LMF (304) in step 355 described above to transmit the SRS measurement result to the LMF (304).

[0075] At step 370, the LMF (304) may transmit an NRPPa POSITIONING DEACTIVATION message to the Serving gNB / TRP (302). (NRPPa POSITIONING DEACTIVATION)

[0076] The NRPPa POSITIONING DEACTIVATION message may be used to transmit to the Serving gNB / TRP (302) to deactivate the SRS transmission requested in step 335 after the LMF (304) has completed the position estimation technique operation.

[0077] FIG. 4 is a diagram illustrating a scenario in which a terminal transmits SRS for location estimation in an RRC_INACTIVE state according to an embodiment of the present disclosure.

[0078] Referring to FIG. 4, the base station (405) may transmit an RRCRelease message to the terminal (401) and instruct the terminal to transition to the RRC_INACTIVE state. At this time, the base station may include in the RRCRelease message (410) one or more configuration information (hereinafter, referred to as SRS-PosRRC-InactiveValidityAreaConfig for ease of explanation) necessary for the terminal to transmit SRS for location estimation in the RRC_INACTIVE state, and each configuration information may be linked to one validity area (430 or 440). Here, the validity area is an area in which each SRS-PosRRC-InactiveValidityAreaConfig is valid, and may be indicated in the form of a list of cells included in the area (more specifically, in the form of a list of identities of each cell). If the RRCRelease message contains multiple SRS-PosRRC-InactiveValidityAreaConfigs, each associated with a different validity area, the base station can indicate that at most one of them is to be activated / applied immediately, and the rest are to be preset (not activated / applied immediately, but preset for later use).

[0079] When a terminal transitions to the RRC_INACTIVE state through the RRCRelease message, the terminal can perform SRS transmission using the SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area X (430) to which the current serving cell or camping on cell belongs, if the terminal is instructed to immediately activate / apply the SRS-PosRRC-InactiveValidityAreaConfig. At this time, even if the terminal moves within the validity area X and performs cell reselection to another cell, the terminal can continue to use the same configuration (i.e., the SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area X (430)) and continue SRS transmission.

[0080] Afterwards, the terminal may continue to move and move to another validity area Y (440). At this time, the terminal may reselect another cell that does not belong to the existing validity area (430). In this case, the RRC layer of the terminal may instruct the lower layer (MAC) to stop the timer (inactivePosSRS-ValidityAreaTAT) used to check the validity of the TA (Timing Advance) value used for location estimation SRS transmission after cell reselection, and the terminal may stop SRS transmission. If the newly reselected cell by the terminal belongs to another validity area Y (440) associated with one of the preset SRS-PosRRC-InactiveValidityAreaConfigs included in the RRCRelease message, the terminal (or the upper layer of the terminal) may initiate the RRCResume procedure to activate the preset corresponding SRS-PosRRC-InactiveValidityAreaConfig. More specifically, the terminal can transmit an RRCResumeRequest message to the base station (407) operating the newly selected cell (i.e., the current serving / camping on cell), and at this time, by setting / setting the resume cause value included in the RRCResumeRequest message to 'srs-PosConfigOrActivationReq', the terminal can request or notify the activation of SRS-PosRRC-InactiveValidityAreaConfig connected to the new validity area Y (430). Afterwards, the base station (407) that receives the RRCResumeRequest message can determine through the resume cause that the terminal requests or notifies the activation of the preset SRS-PosRRC-InactiveValidityAreaConfig.Afterwards, the base station can cause the terminal to transition back to the RRC_INACTIVE state by transmitting the RRCRelease message (414) to the terminal, and can instruct activation in response to the terminal's activation request as needed. Afterwards, the terminal can activate the preset SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area including the newly selected cell and continue transmitting SRS for position estimation in the RRC_INACTIVE state.

[0081] On the other hand, if the newly reselected cell by the UE does not belong to any validity area associated with all the pre-configured SRS-PosRRC-InactiveValidityAreaConfigs included in the RRCRelease message, the UE (or its upper layer) can initiate the RRCResume procedure to request SRS transmission setup in a valid RRC_INACTIVE state in the newly selected cell. More specifically, the UE can transmit an RRCResumeRequest message to the base station corresponding to the newly selected cell (i.e., the current serving / camping on cell), and at this time, the resume cause value included in the RRCResumeRequest message can be set / configured to 'srs-PosConfigOrActivationReq' to request a new SRS transmission setup. Afterwards, the base station receiving the RRCResumeRequest message can determine that the UE requests a new SRS transmission setup through the resume cause. Afterwards, the base station can make the UE transition back to the RRC_INACTIVE state by transmitting an RRCRelease message to the UE. Additionally, the RRCRelease message may include one or more new SRS transmission configurations (SRS-PosRRC-InactiveValidityAreaConfig), each of which may be associated with a validity area. The UE may then activate (or apply) the pre-configured SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area containing the newly selected cell and continue transmitting SRS for position estimation in the RRC_INACTIVE state.

[0082] As described above, by pre-configuring the configuration information required for the position estimation target terminal to transmit the position estimation SRS in the RRC_INACTIVE state, the energy consumed by the position estimation target terminal while transmitting the SRS for position estimation can be reduced. For example, by maintaining the RRC_INCTIVE state and continuing SRS transmission using the same SRS transmission configuration even when the terminal moves and performs cell reselection within a specific validity area, the operation in which the terminal transitions to the RRC_CONNECTED state to transmit new SRS transmission configuration information, which consumes more energy, can be avoided. In addition, by pre-configuring valid SRS configuration information in other adjacent validity areas, the terminal can perform only a simple activation procedure and continue SRS transmission instead of receiving new configuration information when moving to the corresponding validity area.

[0083] FIG. 5 is a diagram illustrating a procedure in which a terminal receives SRS preset information in an RRC_CONNECTED state and transmits one of them after activating it in an RRC_INACTIVE state according to an embodiment of the present disclosure.

[0084] Referring to FIG. 5, a terminal for position estimation may operate in an RRC_CONNTECED state, receive an RRCRelease message from a base station, and transition to an RRC_INACTIVE state. At this time, the RRCRelease message may include one or more pieces of configuration information (hereinafter referred to as SRS-PosRRC-InactiveValidityAreaConfig) necessary for performing SRS transmission for position estimation in the RRC_INACTIVE state. In addition, each SRS-PosRRC-InactiveValidityAreaConfig may be associated with an area (hereinafter referred to as a validity area) in which the configuration information is valid. When an event requiring SRS transmission for position estimation occurs in the RRC_INACTIVE state, the terminal may perform SRS transmission in the RRC_INACTIVE state using the SRS-PosRRC-InactiveValidityAreaConfig configured in advance through the RRCRelease message. Additionally, when the terminal moves from the RRC_INACTIVE state and reselects a cell within a different validity area, it may perform procedures to activate / apply the preset SRS-PosRRC-InactiveValidityAreaConfig or request new SRS configuration information, as needed. A more specific step-by-step procedure can be described as follows.

[0085] In step 510, the LMF (509) and base stations (503, 505) may perform a procedure for configuring the necessary configuration information (hereinafter referred to as SRS-PosRRC-InactiveValidityAreaConfig) for the position estimation target terminal (501) to perform SRS transmission for position estimation in the RRC_INACTIVE state. The signaling procedure between the LMF and base stations required in the procedure is described in more detail in the embodiment of FIG. 6 below.

[0086] In step 513, the serving base station (505) can cause the terminal (501) operating in the RRC_CONNTECTED state to transition to the RRC_INACTIVE state by transmitting an RRCRelease message to the terminal. At this time, the RRCRelease message can include one or more SRS-PosRRC-InactiveValidityAreaConfigs in the form of a list (SRS-PosRRC-InactiveValidityAreaConfigList), and each SRS-PosRRC-InactiveValidityAreaConfig can be associated with an area (hereinafter, referred to as a validity area) in which the corresponding configuration information is valid. In addition, the configuration type (ConfigType) for each SRS-PosRRC-InactiveValidityAreaConfig included in the RRCRelease message can be set to 'preconfig' or 'non-preconfig'. The definition of each ConfigType can be as follows.

[0087] * Non-preconfig type: SRS-PosRRC-InactiveValidityAreaConfig set to 'non-preconfig' can be applied / activated immediately when the terminal receives the RRCRelease message containing the corresponding configuration information.

[0088] * preconfig type: SRS-PosRRC-InactiveValidityAreaConfig set to 'preconfig' is not applied / activated immediately when the terminal receives the RRCRelease message containing the configuration information, but can be applied / activated when a specific event occurs or a specific condition is satisfied.

[0089] When the base station configures one or more SRS-PosRRC-InactiveValidityAreaConfigs to the terminal via the RRCRelease message, the ConfigType of at most one SRS-PosRRC-InactiveValidityAreaConfig may be set to 'non-preconfig'. Or, at least the ConfigType of the SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area to which the serving cell of the current terminal belongs may be set to 'non-preconfig'. This can be described as shown in Table 1 below.

[0090] srs-PosRRC-InactiveValidityAreaConfigListList of SRS for positioning configuration during RRC_INACTIVE state which is valid across a number of cells comprising a validity area. For each validity area, the UE is preconfigured with only one SRS for positioning configuration.(옵션 1): When the network configures multiple validity area, up to one pre-configured SRS can have configType set to 'non-preconfig' and others should have configType set to 'preconfig'.(옵션 2): When the network configures multiple validity area, only the pre-configured SRS for the validity area including the current serving cell can have configType set to 'non-preconfig' and others should have configType set to 'preconfig'.

[0091] If the target terminal for position estimation needs to immediately transmit SRS for position estimation after transitioning to RRC_INACTIVE state, the base station can configure one or more SRS-PosRRC-InactiveValidityAreaConfigs to the terminal through an RRCRelease message, and can configure at most one SRS-PosRRC-InactiveValidityAreaConfig as a 'non-preconfig' type. By doing this, the target terminal for position estimation can skip a separate activation procedure (e.g., 517 and 518) after receiving the RRCRelease message, and can immediately activate / apply the corresponding SRS-PosRRC-InactiveValidityAreaConfig and perform SRS transmission.

[0092] In step 515, the UE can detect an event that requires SRS transmission in RRC_INACTIVE state for position estimation. If one or more SRS-PosRRC-InactiveValidityAreaConfigs are preset in step 513 and the current serving / camping cell of the UE is included in the validity area associated with one of the preset SRS-PosRRC-InactiveValidityAreaConfigs, the upper layer related to position estimation of the UE can request the RRC layer to trigger the RRCResume procedure to activate the corresponding SRS transmission configuration. If the UE is already transmitting SRS after activating / applying a specific SRS-PosRRC-InactiveValidityAreaConfig, the RRCResume procedure may not be requested.

[0093] In step 517, when the RRCResume procedure is triggered in the terminal RRC layer according to the upper layer request as in step 515, the terminal (501) may transmit an RRCResumeRequest message to the base station (505) to activate / apply SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area where the terminal is currently located. At this time, the terminal may set the resume cause value included in the RRCResumeRequest message to 'srs-PosConfigOrActivationReq'. After receiving the RRCResumeRequest message, the base station may know that the terminal requests or notifies the activation of the pre-configured (i.e., ConfigType is 'preconfig') SRS-PosRRC-InactiveValidityAreaConfig based on the resume cause value set by the terminal. More specifically, the following options may be considered as the method and timing for the terminal to activate the pre-configured SRS-PosRRC-InactiveValidityAreaConfig.

[0094] ● Option 1: The terminal can activate the preset SRS-PosRRC-InactiveValidityAreaConfig without explicit activation instruction from the base station after transmitting RRCResumeRequest.

[0095] ■ Option 1-1: After transmitting (or configuring) the RRCResumeRequest message, the UE can activate / apply the SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area that includes the UE's current serving / camping on cell among the preset SRS-PosRRC-InactiveValidityAreaConfig.

[0096] ■ Option 1-2: After transmitting the RRCResumeRequest message, the terminal can activate / apply the SRS-PosRRC-InactiveValidityAreaConfig linked to the validity area including the current serving / camping on cell of the terminal among the preset SRS-PosRRC-InactiveValidityAreaConfig at the time of receiving the corresponding RRCRelease message as in step 518 below.

[0097] ● Option 2: After transmitting the RRCResumeRequest, the terminal may receive an explicit activation instruction from the base station and activate the preset SRS-PosRRC-InactiveValidityAreaConfig as in step 518 below. The specific method by which the base station explicitly instructs activation / application of the preset SRS-PosRRC-InactiveValidityAreaConfig is as described in step 518 below.

[0098] In step 518, the base station can transmit an RRCRelease message to the terminal so that the terminal can transition to the RRC_INACTIVE state and perform SRS transmission. At this time, the base station can explicitly instruct the terminal to activate the preset SRS-PosRRC-InactiveValidityAreaConfig, as in option 2 described in step 517. The following options can be considered as a method for the base station to explicitly instruct the terminal to activate / apply the preset SRS-PosRRC-InactiveValidityAreaConfig.

[0099] ● Option 1: The base station can instruct the terminal to activate / apply the corresponding SRS transmission configuration by re-including the activation target SRS-PosRRC-InactiveValidityAreaConfig in the RRCRelease message and setting the corresponding (or included) ConfigType field's setting value to 'non-preconfig'. The terminal can activate / apply the specific SRS-PosRRC-InactiveValidityAreaConfig and start SRS transmission according to the base station's instruction.

[0100] When a base station wants to set one or more SRS-PosRRC-InactiveValidityAreaConfigs to a terminal, multiple SRS transmission settings can be included in the RRCRelease message in the form of a simple list as shown in Table 2 below.

[0101] SuspendConfig ::= SEQUENCE {srs-PosRRC-InactiveValidityAreaConfigList-r18 SetupRelease { SRS-PosRRC-InactiveValidityAreaConfigList-r18} OPTIONAL -- Need M]]}SRS-PosRRC-InactiveValidityAreaConfigList-r18 ::= SEQUENCE SIZE(1..maxNrOfVA-r18) OF SRS-PosRRC-InactiveValidityAreaConfig-r18SRS-PosRRC-InactiveValidityAreaConfig-r18 ::= SEQUENCE {configType-r18ENUMERATED {preconfig, non-preconfig},srs-PosConfigValidityArea-r18 SEQUENCE (SIZE(1..maxNrOfCellsInVA-r18)) OF CellIdentity,<<omitted>>}

[0102] In this case, even if the base station wants to change only the configType value of a specific SRS-PosRRC-InactiveValidityAreaConfig while maintaining other settings included in the preset list in step 513, the entire list (srs-PosRRC-InactiveValidityAreaConfigList) may need to be included again in the RRCRelease message (518) repeatedly. To improve the signaling load generated in this way, an AddMod (Addition, Modification) list that can modify only some of the contents of multiple SRS-PosRRC-InactiveValidityAreaConfigs included in the list can be used. When AddModList is utilized for SRS presetting, the base station can instruct the terminal to modify or remove only the contents of a specific SRS-PosRRC-InactiveValidityAreaConfig among multiple SRS-PosRRC-InactiveValidityAreaConfigs included in the list and maintain the remaining settings as they are. In order to use the described AddModList operation, ToAddModList, ToReleaseList, and ID of each SRS-PosRRC-InactiveValidityAreaConfig for SRS transmission presetting in RRC_INACTIVE state can be defined as shown in Table 3 below.

[0103] SuspendConfig ::= SEQUENCE {srs-PosRRC-InactiveValidityAreaConfig-r18 SetupRelease { SRS-PosRRC-InactiveValidityAreaConfig-r18} OPTIONAL -- Need M]]}SRS-PosRRC-InactiveValidityAreaConfig-r18 ::=SEQUENCE{SRS-PosRRC-InactiveValidityAreaToAddModList-r18SEQUENCESIZE(1..maxNrOfVA-r18) OF SRS-PosRRC-InactiveValidityAreaConfig-r18OPTIONAL -- Need NSRS-PosRRC-InactiveValidityAreaToReleaseList-r18SEQUENCESIZE(1..maxNrOfVA-r18) OF SRS-PosRRC-InactiveConfigID-r18OPTIONAL -- Need NSRS-PosRRC-InactiveValidityAreaConfig-r18 ::= SEQUENCE {configType-r18 ENUMERATED {preconfig, non-preconfig},SRS-PosRRC-InactiveConfigID-r18INTEGER(1..maxNrOfVA-r18),srs-PosConfigValidityArea-r18 SEQUENCE (SIZE(1..maxNrOfCellsInVA-r18)) OF CellIdentity,<<생략>>}

[0104] ● Option 2: The base station may include a 1-bit indicator in the RRCRelease message to explicitly indicate that it approves / confirms the activation requested by the terminal in step 517. The terminal may activate / apply the SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area including the terminal's current serving / camping on cell among the preset SRS-PosRRC-InactiveValidityAreaConfigs in step 513 according to the indication of the base station and start SRS transmission. When this option is used, the base station can indicate SRS transmission activation only through the 1-bit indicator without having to repeatedly include the preset SRS-PosRRC-InactiveValidityAreaConfigs in the RRCRelease message in step 513.

[0105] At step 519, the base station (505) can report to the LMF (509) that the position estimation terminal (501) has activated a specific preset SRS-PosRRC-InactiveValidityAreaConfig and started SRS transmission within the validity area associated with the configuration. Thereafter, the LMF can instruct the base stations and RPs (Receiving Points) located within the validity area to receive / measure the position estimation SRS transmitted by the terminal in order to estimate the position of the terminal. If the base station does not report the activation of SRS transmission by the terminal to the LMF, the LMF may have to request the base stations and RPs within all validity areas corresponding to all preset SRS-PosRRC-InactiveValidityAreaConfig for the terminal to perform SRS reception / measurement. Therefore, the activation reporting operation can reduce network load and energy consumption by preventing the network from unnecessarily performing blind detection / measurement within all validity areas. The activation report message, which notifies the LMF that the UE has activated a specific SRS-PosRRC-InactiveValidityAreaConfig and initiated SRS transmission within the validity area associated with the configuration, may be either a reused NRPPa POSITIONING INFORMATION UPDATE message or a new NRPPa message may be defined / introduced. If the NRPPa POSITIONING INFORMATION UPDATE is reused, a new field may be defined in the message to indicate the activated / applied SRS configuration information. In addition, a new status (e.g., 'activated') may be introduced as the setting value of the SRS Transmission Status field.When a new NRPPa message (e.g., NRPPa POSITIONING ACTIVATION NOTIFICATION) is introduced as an activation report message, the message may include an activation point, which may be defined as in Table 4 below.

[0106]

[0107] In step 520, the terminal (501) may reselect another cell that does not belong to the existing validity area. In this case, the RRC layer of the terminal may instruct the lower layer (MAC) to stop the timer (inactivePosSRS-ValidityAreaTAT) used to check the validity of the TA (Timing Advance) value used for location estimation SRS transmission after cell reselection, and the terminal may stop SRS transmission. If the reselected cell belongs to another validity area associated with one of the preset SRS-PosRRC-InactiveValidityAreaConfigs included in the RRCRelease message in steps 513 and 518, the terminal (or the upper layer of the terminal) may start the RRCResume procedure as in step 521 below to activate the preset corresponding SRS-PosRRC-InactiveValidityAreaConfig.

[0108] In step 521, when the RRCResume procedure is triggered in the terminal RRC layer according to a higher layer request as in step 520, the terminal (501) may transmit an RRCResumeRequest message to the new serving base station (503) to activate / apply SRS-PosRRC-InactiveValidityAreaConfig associated with the validity area where the terminal is currently located. At this time, the terminal may set the resume cause value included in the RRCResumeRequest message to 'srs-PosConfigOrActivationReq'. For reference, the specific method and timing for the terminal to activate / apply a specific preset SRS-PosRRC-InactiveValidityAreaConfig are as described in step 517.

[0109] In step 523, the new serving base station (503) can determine that the terminal requests a new SRS transmission configuration or requests / notifies the activation of a pre-configured SRS transmission configuration based on the resume cause information in the RRCResume message received from the terminal (501) in step 521. The base station (503) can request UE CONTEXT information of the terminal from the existing serving base station (505) in order to perform the operation requested by the terminal. At this time, in order to inform the existing serving base station (505) why the base station (503) requests UE CONTEXT information of the terminal, the resume cause value included by the terminal in the RRCResumeRequest message in step 521 can be included in the RETRIEVE UE CONTEXT REQUEST message. Additionally, if the new serving base station (503) cannot properly interpret the resume cause value set in the RRCResumeReqeust message in step 521, the new serving base station can immediately transition the terminal to the RRC_IDLE state through the RRCRelease message.

[0110] In step 525, the existing serving base station (505) may transmit a RETRIEVE UE CONTEXT RESPONSE message to the new serving base station (503) in response to the RETRIEVE UE CONTEXT REQUEST message in step 523. The RETRIEVE UE CONTEXT RESPONSE message may include a HandoverPreparationInformation message defined in the RRC standard as UE CONTEXT information required for the Resume procedure. At this time, the HandoverPreparationInformation message may also include SRS configuration information (e.g., srs-PosRRC-Inactive and srs-PosRRC-InactiveValidityAreaConfigList) that was configured for the terminal (501) through the RRCRelease message in steps 518 and 526. The existing serving base station (505) can determine whether the resume procedure is related to SRS transmission configuration based on the resume cause value received from the new serving base station (503) in step 523 and determine whether to include SRS configuration information in the RETRIEVE UE CONTEXT RESPONSE message (or HandoverPreparationInformation message). If the terminal (501) starts the RRCResume procedure by setting the resume cause value to 'srs-PosConfigOrActivationReq' in step 521 and the SRS configuration information is not included in the RETRIEVE UE CONTEXT RESPONSE message, the new serving base station (503) may not accurately determine the intent of the resume cause 'srs-PosConfigOrActivationReq' set by the terminal.More specifically, if the SRS-PosRRC-InactiveValidityAreaConfig linked to the validity area including the new serving cell has been configured in advance, the base station can interpret the intention of the terminal as a request for activation of the corresponding configuration. On the other hand, if the SRS-PosRRC-InactiveValidityAreaConfig linked to the validity area including the new serving cell has not been configured in advance, the base station can interpret the intention of the terminal as a request for new SRS configuration. However, if the SRS configuration information is not included in the RETRIEVE UE CONTEXT RESPONSE message, the new serving base station (503) cannot accurately determine the intention of the resume cause 'srs-PosConfigOrActivationReq' configured by the terminal as described. This is a problem that occurs because the terminal uses the same resume cause 'srs-PosConfigOrActivationReq' together with the activation request of the preset SRS-PosRRC-InactiveValidityAreaConfig or the new SRS transmission configuration request, as described in FIG. 4. Since the operation of the new serving base station (503) may vary depending on how it interprets the intention of the actual terminal, if the existing serving base station (505) determines that the resume procedure is related to SRS transmission setup through the resume cause included in the RETRIEVE UE CONTEXT REQUEST message in step 523, it may include SRS setup information preset for the terminal in the RETRIEVE UE CONTEXT RESPONSE message.

[0111] In step 526, the serving base station (503) can transmit an RRCRelease message to the terminal (501) so that the terminal can perform SRS transmission after transitioning to the RRC_INACTIVE state. At this time, the base station can instruct the terminal to activate the SRS-PosRRC-InactiveValidityAreaConfig that is explicitly preset, as in option 2 described in step 517. A specific method for the base station to instruct the terminal to activate / apply the SRS-PosRRC-InactiveValidityAreaConfig that is explicitly preset is as described in step 518.

[0112] At step 528, the serving base station (503) may report to the LMF (509) that the location estimation terminal (501) has activated a preset specific SRS-PosRRC-InactiveValidityAreaConfig and started SRS transmission within the validity area associated with the configuration. The expected effect and specific embodiment of the activation report are as described at step 519.

[0113] FIG. 6 is a diagram illustrating a procedure for a base station and an LMF to pre-configure SRS configuration information available to a terminal in an RRC_INACTIVE state according to one embodiment of the present disclosure.

[0114] Referring to FIG. 6, the LMF (608) may decide to configure SRS pre-configuration information (hereinafter referred to as “pre-configured SRS configuration”) required for a location estimation target terminal (601) to transmit SRS while moving between one or more validity areas in an RRC_INACTIVE state. To this end, the LMF may perform a procedure for pre-securing valid SRS transmission configuration information within a serving validity area (605) including the current serving cell of the terminal and an adjacent neighbor validity area (602) together with one or more base stations (603, 604, 606, 607) within each validity area. Thereafter, the LMF may transmit valid pre-configured SRS configurations in the form of a list in each of one or more validity areas to the serving base station (607) of the terminal. Finally, the serving base station may transmit one or more pre-configured SRS configurations in the form of a list to the terminal via an RRCRelease message. At this time, each pre-configured SRS configuration can be associated with one validity area, which can correspond to SRS-PosRRC-InactiveValidityAreaConfig in step 513 of FIG. 5. The operation of each step can be described in detail as follows.

[0115] At step 610, the LMF (608) may decide to configure SRS preset information required for the location estimation target terminal (501) to transmit SRS while moving between one or more validity areas in the RRC_INACTIVE state. More specifically, a list of cells constituting each validity area and characteristic information (Requested SRS Transmission Characteristics) of the SRS transmission settings required in each validity area may be determined.

[0116] In step 612, the LMF (608) may randomly select one of the base stations (604) operating cells within each validity area configured in step 610 and request SRS transmission configuration information to be used within the validity area from the base station. At this time, the validity area configuration information (i.e., the list of cells constituting the validity area) and the requested SRS transmission configuration characteristic information (Requested SRS Transmission Characteristics) may be included in the request. For the request, a new NRPPa message (e.g., NRPPa POSITIONING SRS PRECONFIGURATION REQUEST) may be defined as shown in Table 5 below.

[0117]

[0118] In step 613, the base station (604), which has received a request for SRS transmission configuration information to be used within the validity area from the LMF (608) in step 612, may determine the SRS configuration information to be used within the validity area and the final validity area configuration (a list of cells included within the validity area) and respond to the LMF with the same. For the response, a new NRPPa message (e.g., NRPPa POSITIONING SRS PRECONFIGURATION RESPONSE) may be defined as shown in Table 6 below.

[0119]

[0120]

[0121] Additionally, if it is necessary to secure valid SRS configuration information in advance for a serving validity area (605) including the current serving base station (607), the LMF may perform the procedures of steps 612 and 613 with the serving base station.

[0122] Also, although omitted in this drawing, if the base station (604) that has received a request for SRS transmission configuration information to be used within the validity area from the LMF (608) in step 612 fails to pre-configure the SRS configuration information to be used within the validity area, it may report this to the LMF. At this time, the cause of the failure may also be reported. For such a report, a new NRPPa message (e.g., NRPPa POSITIONING SRS PRECONFIGURATION FAILURE) may be defined as shown in Table 7 below.

[0123]

[0124] In step 614, the LMF (608) may notify / instruct SRS presetting (i.e., SRS presetting resource reservation) by transmitting the SRS presetting information to be used within each validity area responded to in step 613 to other base stations (603 and 606) included within the validity area. An NRPPa message for notification / instruction (e.g., NRPPa SRS INFORMATION RESERVATION NOTIFICATION) may be configured as shown in Table 8 below.

[0125]

[0126] Note that if LMF decides to pre-configure SRS transmission settings for multiple validity areas in step 610, steps 612, 613, and 614 may be performed repeatedly (in parallel) for each of the multiple validity areas.

[0127] In step 615, the LMF (608) may request the serving base station (607) to configure SRS transmission for position estimation for the position estimation target terminal (501). At this time, the LMF may also request SRS pre-configuration so that the position estimation target terminal can perform SRS transmission while moving between multiple validity areas in the RRC_INACTIVE state. More specifically, the request may include configuration information of the serving validity area (605) including the serving base station (in other words, a list of cells constituting the serving validity area) and requested SRS transmission configuration characteristic information (Requested SRS Transmission Characteristics). Additionally, through steps 612, 613, and 614, SRS pre-configuration information prepared for each neighboring validity area (pre-configured SRS configuration) and configuration information of each validity area may be included together in the form of a list (Pre-configured SRS Configuration List). An NRPPa message for a request (e.g., NRPPa POSITIONING INFORMATION REQUEST) can be structured as shown in Table 9 below.

[0128]

[0129]

[0130] In step 620, the serving base station (607) can transition the terminal (501) to the RRC_INACTIVE state through the RRCRelease message. At this time, one or more pre-configured SRS configurations received from the LMF (608) through step 615 can be included in the RRCRelease message in the form of a list. At this time, each pre-configured SRS configuration can be associated with one validity area, which can correspond to SRS-PosRRC-InactiveValidityAreaConfig in step 513 of FIG. 5.

[0131] FIG. 7 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0132] Referring to the drawing, the terminal may include an RF (Radio Frequency) processing unit (710), a baseband processing unit (720), a storage unit (730), and a control unit (740).

[0133] The RF processing unit (710) can perform functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (710) can up-convert a baseband signal provided from the baseband processing unit (720) into an RF band signal and then transmit it through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (710) can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In the drawing, only one antenna is illustrated, but the terminal can be equipped with multiple antennas. In addition, the RF processing unit (710) can include multiple RF chains. Furthermore, the RF processing unit (710) can perform beamforming. For beamforming, the RF processing unit (710) can adjust the phase and amplitude of each signal transmitted and received through multiple antennas or antenna elements. In addition, the RF processing unit can perform MIMO and receive multiple layers when performing MIMO operations.

[0134] The baseband processing unit (720) can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (720) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (720) can restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (710). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (720) can generate complex symbols by encoding and modulating a transmission bit stream, map the complex symbols to subcarriers, and then configure OFDM symbols through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit (720) divides the baseband signal provided from the RF processing unit (710) into OFDM symbol units, restores signals mapped to subcarriers through FFT (fast Fourier transform) operation, and then restores the received bit string through demodulation and decoding.

[0135] The baseband processing unit (720) and the RF processing unit (710) can transmit and receive signals as described above. Accordingly, the baseband processing unit (720) and the RF processing unit (710) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (720) and the RF processing unit (710) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (720) and the RF processing unit (710) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), etc. Additionally, different frequency bands may include super high frequency (SHF) (e.g., 2.NRHz, NRhz) bands, millimeter wave (mm wave) (e.g., 60GHz) bands.

[0136] The storage unit (730) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (730) can store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit (730) can provide the stored data at the request of the control unit (740).

[0137] The control unit (740) can control the overall operations of the terminal. For example, the control unit (740) can transmit and receive signals through the baseband processing unit (720) and the RF processing unit (710). In addition, the control unit (740) can record and read data in the storage unit (740). For this purpose, the control unit (740) can include at least one processor. For example, the control unit (740) can include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0138] FIG. 8 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0139] As shown in the drawing, the base station may be configured to include an RF processing unit (810), a baseband processing unit (820), a backhaul communication unit (830), a storage unit (840), and a control unit (850).

[0140] The RF processing unit (810) may perform functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (810) may up-convert a baseband signal provided from the baseband processing unit (820) into an RF band signal and transmit the same through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (810) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In the drawing, only one antenna is illustrated, but the first access node may have multiple antennas. In addition, the RF processing unit (810) may include multiple RF chains. Furthermore, the RF processing unit (810) may perform beamforming. For beamforming, the RF processing unit (810) may adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. The RF processing unit can perform downlink MIMO operations by transmitting one or more layers.

[0141] The baseband processing unit (820) can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (820) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (820) can restore the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (810). For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit (820) can generate complex symbols by encoding and modulating a transmission bit stream, map the complex symbols to subcarriers, and then configure OFDM symbols through an IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (820) can divide the baseband signal provided from the RF processing unit (810) into OFDM symbol units, restore the signals mapped to subcarriers through FFT operation, and then restore the received bit string through demodulation and decoding. The baseband processing unit (820) and the RF processing unit (810) can transmit and receive signals as described above. Accordingly, the baseband processing unit (820) and the RF processing unit (810) can be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0142] The backhaul communication unit (830) may provide an interface for performing communication with other nodes within the network. That is, the backhaul communication unit (830) may convert a bit string transmitted from a primary base station to another node, such as an auxiliary base station or core network, into a physical signal, and may convert a physical signal received from another node into a bit string.

[0143] The storage unit (840) can store data such as basic programs, application programs, and configuration information for the operation of the main base station. In particular, the storage unit (840) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. Furthermore, the storage unit (840) can store information that serves as a basis for determining whether to provide or terminate multiple connections to a terminal. Furthermore, the storage unit (840) can provide stored data upon request from the control unit (850).

[0144] The control unit (850) controls the overall operations of the base station. For example, the control unit (850) transmits and receives signals through the baseband processing unit (820) and the RF processing unit (810) or through the backhaul communication unit (830). In addition, the control unit (850) records and reads data in the storage unit (840). For this purpose, the control unit (850) may include at least one processor.

[0145] FIG. 9 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0146] Referring to FIG. 9, a terminal according to one embodiment may include a transceiver (910), a memory (920), and a processor (930). The transceiver (910), the memory (920), and the processor (930) of the UE may operate according to the communication method of the terminal described above. However, the components of the terminal are not limited thereto. For example, the terminal may include more or fewer components than those described above. In addition, the processor (930), the transceiver (910), and the memory (920) may be implemented as a single chip. In addition, the processor (930) may include at least one processor. In addition, the terminal of FIG. 9 may correspond to the terminal of FIG. 7.

[0147] The transceiver (910) collectively refers to the UE receiver and the UE transmitter, and can transmit and receive signals with a base station or network entity. The signals transmitted and received with the base station or network entity may include control information and data. The transceiver (910) may include an RF transmitter for up-converting and amplifying the frequency of a transmission signal, and an RF receiver for low-noise amplification and down-converting the frequency of a reception signal. However, this is only an example of the transceiver (910), and the components of the transceiver (910) are not limited to the RF transmitter and RF receiver.

[0148] In addition, the transceiver (910) can receive a signal through a wireless channel and output it to the processor (930), and transmit the signal output from the processor (930) through the wireless channel. The memory (920) can store programs and data necessary for the operation of the UE. In addition, the memory (920) can store control information or data included in a signal acquired by the UE. The memory (920) can be a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0149] The processor (930) can control a series of processes to enable the terminal to operate. For example, the transceiver (910) can receive a data signal including a control signal transmitted by a base station or network entity, and the processor (930) can determine the result of receiving the control signal and data signal transmitted by the base station or network entity. The processor (930) of FIG. 9 may correspond to the control unit (740) of FIG. 7.

[0150] FIG. 10 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure.

[0151] Referring to FIG. 10, a base station according to one embodiment may include a transceiver (1010), a memory (1020), and a processor (1030). The transceiver (1010), the memory (1020), and the processor (1030) of the base station may operate according to the communication method of the base station described above. However, the components of the base station are not limited thereto. For example, the base station may include more or fewer components than the components described above. In addition, the processor (1030), the transceiver (1010), and the memory (1020) may be implemented as a single chip. In addition, the processor (1030) may include at least one processor. In addition, the base station of FIG. 10 may correspond to the base station of FIG. 8.

[0152] The transceiver (1010) collectively refers to a base station receiver and a base station transmitter, and can transmit and receive signals with a terminal (UE) or a network entity. The signals transmitted and received with the terminal or network entity may include control information and data. The transceiver (1010) may include an RF transmitter for up-converting and amplifying the frequency of a transmission signal and an RF receiver for low-noise amplifying and down-converting the frequency of a reception signal. However, this is only an example of the transceiver (1010), and the components of the transceiver (1010) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (1010) may receive a signal through a wireless channel and output it to the processor (1030), and transmit a signal output from the processor (1030) through the wireless channel.

[0153] The memory (1020) can store programs and data required for the operation of the base station. In addition, the memory (1020) can store control information or data included in signals acquired by the base station. The memory (1020) can be a storage medium such as a read-only memory (ROM), a random access memory (RAM), a hard disk, a CD-ROM, a DVD, or a combination of storage media. The processor (1030) can control a series of processes so that the base station operates as described above. For example, the transceiver (1010) can receive a data signal including a control signal transmitted by a terminal, and the processor (1030) can determine the result of receiving the control signal and the data signal transmitted by the terminal. The processor (1030) of FIG. 10 may correspond to the control unit (850) of FIG. 8.

[0154] Meanwhile, the embodiments of the present invention disclosed in this specification and drawings are merely specific examples presented to easily explain the technical content of the present invention and facilitate understanding of the present invention, and are not intended to limit the scope of the present invention. In other words, it will be apparent to those skilled in the art that other modifications based on the technical concept of the present invention are possible. Furthermore, one or more of the embodiments may be combined and operated as needed.

[0155] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

[0156] Meanwhile, the message names and IE names included in the detailed description of the present disclosure may be used as other names for the same function, as an example.

Claims

1. In a method performed by a terminal of a wireless communication system, A step of receiving a list of configuration information related to SRS (sounding reference signal) in an RRC (radio resource control) inactive state; A step of transmitting a first message for an RRC resumption request to a base station; A step of receiving a second message for RRC release from the base station; and A method comprising a step of applying the configuration information of the list based on a validity area including the camped cell of the terminal among the list, based on the reception of the second message.

2. In paragraph 1, The above first message contains a cause value for RRC resumption, The above cause value indicates the activation of SRS, the method.

3. In paragraph 1, The above first message contains a cause value for RRC resumption, The above cause value indicates a request for the above setting information, The above method, Further comprising the step of receiving the requested setting information from the base station. method.

4. In paragraph 1, A method wherein the applying step includes a step of transmitting the SRS in the RRC inactive state according to the setting information.

5. In a method performed by a first base station of a wireless communication system, A step of receiving a first message for a radio resource control (RRC) resumption request from a terminal; A step of transmitting a second message to a second base station, which is the last serving base station of the terminal, for requesting CONTEXT of the terminal; A step of receiving a third message including the CONTEXT of the terminal from the second base station; and A method comprising the step of transmitting a fourth message for RRC release to the terminal.

6. In paragraph 5, The above first message contains a cause value for RRC resumption, The above cause value indicates the activation of SRS (sounding reference signal), A method wherein the second message includes the cause value.

7. In paragraph 5, The third message includes a HandoverPreparationInformation message, A method wherein the HandoverPreparationInformation message includes configuration information related to SRS in an RRC inactive state set for the terminal.

8. In paragraph 5, The fifth message to notify the activation of the configuration information related to SRS in the RRC inactive state set to the above terminal is transmitted to the LMF (location management function) entity, The fifth message above includes the NRPPa POSITIONING INFORMATION UPDATE message, A method wherein the NRPPa POSITIONING INFORMATION UPDATE message includes information indicating whether the setting information is activated.

9. In the terminal of a wireless communication system, Transmitter and receiver; and Includes a control unit connected to the above transmitter and receiver, The above control unit: Receive a list of configuration information related to SRS (sounding reference signal) in RRC (radio resource control) inactive state, To the base station, transmit a first message for an RRC resumption request, Receive a second message for RRC release from the base station, and A terminal configured to apply the configuration information of the list based on a validity area including the camped cell of the terminal among the list, based on the reception of the second message.

10. In paragraph 9, The above first message contains a cause value for RRC resumption, The above cause value indicates the activation of SRS, terminal.

11. In paragraph 9, The above first message contains a cause value for RRC resumption, The above cause value indicates a request for the above setting information, The above control unit, Set to receive the requested setting information from the above base station, Terminal.

12. In paragraph 9, the control unit: A terminal configured to transmit the SRS in the RRC inactive state according to the above setting information.

13. In the first base station of the wireless communication system, Transmitter and receiver; and Includes a control unit connected to the above transmitter and receiver, The above control unit: Receive a first message for a radio resource control (RRC) resumption request from the terminal, Transmitting a second message to the second base station, which is the last serving base station of the terminal, to request the CONTEXT of the terminal; Receive a third message including the CONTEXT of the terminal from the second base station, A first base station configured to transmit a fourth message for RRC connection release to the terminal.

14. In paragraph 13, The above first message contains a cause value for RRC resumption, The above cause value indicates the activation of SRS (sounding reference signal), The second message includes the cause value, the first base station.

15. In paragraph 13, The third message includes a HandoverPreparationInformation message, The above HandoverPreparationInformation message includes configuration information related to SRS in the RRC inactive state set for the terminal, The fifth message to notify the activation of the configuration information related to SRS in the RRC inactive state set to the above terminal is transmitted to the LMF (location management function) entity, The fifth message above includes the NRPPa POSITIONING INFORMATION UPDATE message, The first base station, wherein the NRPPa POSITIONING INFORMATION UPDATE message includes information indicating whether the setting information is activated.

Images