WO2025127671A1 - Machine learning-based mobility control method and apparatus - Google Patents

Abstract

A machine learning-based mobility control method and apparatus are disclosed. The method of a user equipment (UE) comprises the steps of: receiving first artificial intelligence (AI)/machine learning (ML)-mobility configuration information for mobility control from a first communication node; checking, on the basis of the first AI/ML-mobility configuration information, a first prediction time when the UE leaves a first service area of the first communication node; determining whether the UE leaves the first service area of the first communication node at the first prediction time; checking, on the basis of the first AI/ML-mobility configuration information, a second prediction time when the UE enters a second service area of a second communication node; and performing a mobility procedure with the second communication node on the basis of the second prediction time.

Description

Method and device for machine learning-based mobility control

The present disclosure relates to mobility control technology, and more particularly, to technology for machine learning-based mobility control in a communication network.

Mobile wireless networks, which are infrastructure networks for the 4th industrial revolution, can support various forms of wireless access points (e.g., transmission and reception points (TRPs), remote radio headers (RRHs), relays, repeaters, etc.), communication nodes with function split, mobile services using satellites (e.g., non-terrestrial networks (NTNs)), radio resource management based on RAN (radio access network) slicing, multi-connectivity functions between small cells and macro cells, multi-connectivity functions between different radio access technologies (RATs), various forms of terminals (e.g., wearable devices, IoT (Internet of Things) devices), and/or various forms of services (e.g., autonomous driving services, IoT services) to process explosively increasing wireless data.

Meanwhile, chat GPT (Generative Pre-trained Transformer) can be applied to all industrial fields. Machine learning (e.g., artificial intelligence)-based functions can be applied to communication networks. Machine learning-based functions can be applied to support connection control and mobility functions for various types of terminals and/or communication nodes to which functional separation is applied. In this case, specific methods for machine learning-based connection control and/or specific methods for machine learning-based mobility control are required.

The purpose of the present disclosure to solve the above problems is to provide a method and device for machine learning-based mobility control in a communication network.

According to embodiments of the present disclosure for achieving the above object, a method of a UE (user equipment) includes: receiving first AI (Artificial Intelligence)/ML (Machine Learning)-mobility configuration information for mobility control from a first communication node; confirming a first predicted time at which the UE leaves a first service area of the first communication node based on the first AI/ML-mobility configuration information; determining whether the UE leaves the first service area of the first communication node at the first predicted time; confirming a second predicted time at which the UE enters a second service area of a second communication node based on the first AI/ML-mobility configuration information; and performing a mobility procedure with the second communication node based on the second predicted time.

The above first AI/ML-mobility configuration information may include at least one of information about a time when the UE leaves the first service area of the first communication node, information about a time when the UE enters the second service area of the second communication node, an event condition set for the mobility control, a geographical location set for the mobility control, or location information of a neighboring communication node.

When the UE is in an RRC (radio resource control) connection state to the first communication node, the first AI/ML-mobility configuration information can be received via a dedicated control message of the first communication node.

When the UE is in an RRC inactive state or an RRC idle state with respect to the first communication node, the first AI/ML-mobility configuration information can be received via system information of the first communication node or a UE state transition control message.

During the period from the first prediction time to the second prediction time, the cell search procedure of the UE may be deactivated.

During the period from the first prediction time to the second prediction time, the operation state of the UE may be an RRC inactive state or an RRC idle state.

When the UE enters the second service area, the mobility procedure between the UE and the second communication node can be performed without exchanging a control message for supporting the mobility procedure between the UE and the first communication node.

The mobility procedure between the UE and the second communication node may be performed before or at the second predicted time.

The method of the UE may further include a step of receiving, from the first communication node, radio resource configuration information allocated by the second communication node, wherein the radio resource configuration information may be used for transmission and reception of at least one of downlink scheduling information or timing information of the second communication node.

If the mobility procedure between the UE and the second communication node is completed, the method may further include receiving second AI/ML-mobility setting information for mobility control from the second communication node.

The method may further include: a step of updating AI/ML-mobility parameters based on the second AI/ML-mobility setting information; and a step of transmitting AI/ML-mobility reporting information including the updated AI/ML-mobility parameters to the second communication node.

The above mobility procedure may be a cell switching procedure, a beam switching procedure, an access procedure, a cell selection procedure, a cell reselection procedure, or a handover procedure, and each of the first communication node and the second communication node may be a base station, a cell, or a transmission and reception point (TRP).

According to embodiments of the present disclosure for achieving the above object, a user equipment (UE) includes at least one processor, wherein the at least one processor causes the UE to receive first AI (Artificial Intelligence)/ML (Machine Learning)-mobility configuration information for mobility control from a first communication node; determine a first predicted time at which the UE leaves a first service area of the first communication node based on the first AI/ML-mobility configuration information; determine whether the UE leaves the first service area of the first communication node at the first predicted time; determine a second predicted time at which the UE enters a second service area of a second communication node based on the first AI/ML-mobility configuration information; and perform a mobility procedure with the second communication node based on the second predicted time.

The above first AI/ML-mobility configuration information may include at least one of information about a time when the UE leaves the first service area of the first communication node, information about a time when the UE enters the second service area of the second communication node, an event condition set for the mobility control, a geographical location set for the mobility control, or location information of a neighboring communication node.

When the UE is in an RRC (radio resource control) connection state to the first communication node, the first AI/ML-mobility configuration information can be received via a dedicated control message of the first communication node.

When the UE is in an RRC inactive state or an RRC idle state with respect to the first communication node, the first AI/ML-mobility configuration information can be received via system information of the first communication node or a UE state transition control message.

During the period from the first prediction time to the second prediction time, the cell search procedure of the UE may be deactivated.

During the period from the first prediction time to the second prediction time, the operation state of the UE may be an RRC inactive state or an RRC idle state.

When the UE enters the second service area, the mobility procedure between the UE and the second communication node can be performed without exchanging a control message for supporting the mobility procedure between the UE and the first communication node.

The at least one processor may further cause the UE to receive, from the first communication node, radio resource configuration information allocated by the second communication node, wherein the radio resource configuration information may be used for transmission and reception of at least one of downlink scheduling information or timing information of the second communication node.

According to the present disclosure, in a communication network composed of various communication nodes (e.g., satellites, aerial vehicles, etc.), a machine learning (e.g., artificial intelligence)-based mobility control/management function can be introduced by considering the state of a mobile device (e.g., a wireless terminal mounted on a mobile device) and/or a terminal in an access link between a terminal and a communication node. The mobile device may include an unmanned aerial vehicle, a train, a ship, an autonomous vehicle, a vehicle using navigation, etc. Based on the machine learning-based mobility control/management function, a beam management procedure, a communication node setting/release/change procedure, etc. can be efficiently performed. Accordingly, the performance of a communication service can be improved. The performance of the communication service can be maintained during the performance of a mobility procedure. In other words, the degradation of the performance of the communication service during the performance of a mobility procedure can be alleviated.

Figure 1 is a conceptual diagram illustrating embodiments of a communication network.

Figure 2 is a block diagram illustrating embodiments of the device.

Figure 3 is a conceptual diagram illustrating examples of operating states of terminals in a communication network.

Figure 4 is a conceptual diagram illustrating embodiments of a method for setting a bandwidth portion in a communication network.

Figure 5 is a conceptual diagram illustrating embodiments of a communication network.

FIG. 6 is a conceptual diagram illustrating embodiments of a method for providing a service using multiple wireless access points in a communication network.

Figures 7a, 7b, and 7c are conceptual diagrams illustrating the configuration of a base station that provides communication services to terminals.

Figure 8 is a conceptual diagram illustrating an embodiment of service provision and mobility function support in air nodes and ground nodes.

FIG. 9 is a conceptual diagram illustrating a mobility control operation according to a change in wireless channel quality in the movement path of the terminal (804-1) of FIG. 8.

FIG. 10 is a conceptual diagram illustrating a mobility control operation according to a change in wireless channel quality in the movement path of the terminal (804-2) of FIG. 8.

Figure 11 is a flowchart illustrating a mobility control procedure.

The present disclosure may have various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present disclosure to specific embodiments, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present disclosure.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are only used to distinguish one component from another. For example, without departing from the scope of the present disclosure, the first component could be referred to as the second component, and similarly, the second component could also be referred to as the first component. The term "and/or" includes any combination of a plurality of related listed items or any item among a plurality of related listed items.

In embodiments of the present disclosure, “at least one of A and B” can mean “at least one of A or B” or “at least one of combinations of one or more of A and B.” Furthermore, in embodiments of the present disclosure, “at least one of A and B” can mean “at least one of A or B” or “at least one of combinations of one or more of A and B.” A and/or B can mean at least one of A or B. A/B can mean at least one of A or B.

When it is said that a component is "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components in between. On the other hand, when it is said that a component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

The terminology used in this disclosure is only used to describe specific embodiments and is not intended to be limiting of the present disclosure. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this disclosure, it should be understood that the terms "comprises" or "has" and the like are intended to specify that a feature, number, step, operation, component, part or combination thereof described in the specification is present, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined in this disclosure.

Hereinafter, with reference to the attached drawings, preferred embodiments of the present disclosure will be described in more detail. In order to facilitate an overall understanding in describing the present disclosure, the same reference numerals are used for the same components in the drawings, and redundant descriptions of the same components are omitted.

A communication network to which embodiments according to the present disclosure are applied will be described. The communication network may be a 4G communication network (e.g., a long-term evolution (LTE) communication network, LTE-A communication network), a 5G communication network (e.g., a new radio (NR) communication network), a 6G communication network, etc. The 4G communication network can support communication in a frequency band of 6 GHz or less, and the 5G communication network can support communication in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. The communication network to which embodiments according to the present disclosure are applied is not limited to the contents described below, and the embodiments according to the present disclosure can be applied to various communication networks. Here, the communication network may be used with the same meaning as a communication system and/or a wireless access system. In the communication network, “LTE” may indicate a “4G communication network”, an “LTE communication network”, or an “LTE-A communication network”, and “NR” may indicate a “5G communication network” or an “NR communication network”.

In an embodiment, "an operation (e.g., a transmission operation) is set" may mean that "setting information for the operation (e.g., an information element, a parameter)" and/or "information instructing performance of the operation" are signaled. "An information element (e.g., a parameter) is set" may mean that the information element is signaled. The signaling may be at least one of system information (SI) signaling (e.g., transmission of a system information block (SIB) and/or a master information block (MIB)), radio resource control (RRC) signaling (e.g., transmission of RRC parameters and/or higher layer parameters), medium access control (MAC) control element (CE) signaling, or PHY signaling (e.g., transmission of downlink control information (DCI), uplink control information (UCI), and/or sidelink control information (SCI)).

Figure 1 is a conceptual diagram illustrating embodiments of a communication network.

Referring to FIG. 1, the communication network (100) may include a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication network (100) may further include a core network (e.g., an S-GW (serving-gateway), a P-GW (PDN (packet data network)-gateway), a MME (mobility management entity)). When the communication network (100) is a 5G communication network (e.g., an NR (new radio) network), the core network may include an AMF (access and mobility management function), an UPF (user plane function), an SMF (session management function), etc. The communication network (100) may mean a wireless access network.

A plurality of communication nodes (110 to 130) can support a communication protocol specified in a 3rd generation partnership project (3GPP) standard (e.g., LTE communication protocol, LTE-A communication protocol, NR communication protocol, etc.). The plurality of communication nodes (110 to 130) may support CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division multiplexing) technology, Filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA technology, NOMA (non-orthogonal multiple access) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (space division multiple access) technology, etc. Each of the plurality of communication nodes may mean an apparatus or a device. The embodiments can be performed by a device or a device. The structure of the device (e.g., the device) can be as follows.

Figure 2 is a block diagram illustrating embodiments of the device.

Referring to FIG. 2, the device (200) may include at least one processor (210), a memory (220), and a transceiver device (230) that is connected to a network and performs communication. In addition, the device (200) may further include an input interface device (240), an output interface device (250), a storage device (260), etc. Each component included in the device (200) may be connected by a bus (270) and may communicate with each other.

The processor (210) can execute a program command stored in at least one of the memory (220) and the storage device (260). The processor (210) may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present disclosure are performed. Each of the memory (220) and the storage device (260) may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory (220) may be configured with at least one of a read only memory (ROM) and a random access memory (RAM).

Referring again to FIG. 1, the communication network (100) may include a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) and a plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) may form a macro cell. Each of the fourth base station (120-1) and the fifth base station (120-2) may form a small cell. The fourth base station (120-1), the third terminal (130-3), and the fourth terminal (130-4) may be within the cell coverage of the first base station (110-1). The second terminal (130-2), the fourth terminal (130-4), and the fifth terminal (130-5) may be within the cell coverage of the second base station (110-2). The fifth base station (120-2), the fourth terminal (130-4), the fifth terminal (130-5), and the sixth terminal (130-6) may be within the cell coverage of the third base station (110-3). The first terminal (130-1) may be within the cell coverage of the fourth base station (120-1). The sixth terminal (130-6) may be within the cell coverage of the fifth base station (120-2).

Here, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be referred to as a NodeB (NB), an evolved NodeB (eNB), a gNB, an advanced base station (ABS), a high reliability-base station (HR-BS), a base transceiver station (BTS), a radio base station, a radio transceiver, an access point, an access node, a radio access station (RAS), a mobile multihop relay-base station (MMR-BS), a relay station (RS), an advanced relay station (ARS), a high reliability-relay station (HR-RS), a home NodeB (HNB), a home eNodeB (HeNB), a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), etc.

Each of the plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) may be referred to as a user equipment (UE), terminal equipment (TE), advanced mobile station (AMS), high reliability-mobile station (HR-MS), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable subscriber station, node, device, OBU (on board unit), etc.

Meanwhile, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may operate in a different frequency band or may operate in the same frequency band. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be connected to each other via an ideal backhaul link or a non-ideal backhaul link, and may exchange information with each other via the ideal backhaul link or the non-ideal backhaul link. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may be connected to a core network via an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit a signal received from the core network to the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6), and can transmit a signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) to the core network. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can be installed in a satellite, an airborne vehicle, an unmanned aerial vehicle, a train, a ship, an automobile, a building on the ground, a streetlight, a traffic light, a guide sign, a dedicated installation facility for a communication node, etc.

In addition, each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) may support MIMO transmission (e.g., single user (SU)-MIMO, multi user (MU)-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, device to device communication (D2D) (or, proximity services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), etc. Here, each of the plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) can perform an operation corresponding to the base station (110-1, 110-2, 110-3, 120-1, 120-2) and an operation supported by the base station (110-1, 110-2, 110-3, 120-1, 120-2). For example, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) based on the SU-MIMO scheme, and the fourth terminal (130-4) can receive a signal from the second base station (110-2) by the SU-MIMO scheme. Alternatively, the second base station (110-2) can transmit signals to the fourth terminal (130-4) and the fifth terminal (130-5) based on the MU-MIMO method, and each of the fourth terminal (130-4) and the fifth terminal (130-5) can receive signals from the second base station (110-2) by the MU-MIMO method.

Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can transmit a signal to the fourth terminal (130-4) based on the CoMP scheme, and the fourth terminal (130-4) can receive a signal from the first base station (110-1), the second base station (110-2), and the third base station (110-3) based on the CoMP scheme. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit and receive a signal with terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) within its cell coverage based on the CA scheme. Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can control D2D between the fourth terminal (130-4) and the fifth terminal (130-5), and each of the fourth terminal (130-4) and the fifth terminal (130-5) can perform D2D under the control of the second base station (110-2) and the third base station (110-3).

Figure 3 is a conceptual diagram illustrating examples of operating states of terminals in a communication network.

Referring to FIG. 3, the state (e.g., operating state) of a terminal in an RRC layer of a communication network can be classified into an RRC connected state, an RRC inactive state, and an RRC idle state. When the terminal operates in an RRC connected state or an RRC inactive state, a base station of a radio access network (RAN) and the terminal can store and/or manage at least one of RRC connection configuration information, RRC context information, or AS (access stratum) context information of the terminal.

A terminal in an RRC connection state can receive allocation information of a physical layer control channel and/or a reference signal required for maintaining RRC connection establishment and/or transmitting and receiving packets. The reference signal may be a reference signal for demodulating data, a reference signal for measuring channel quality, and/or a reference signal for beamforming. A terminal in an RRC connection state can transmit and receive packets without a separate delay. In the present disclosure, a packet may mean data, a data unit, and/or information.

A terminal in the RRC inactive state can perform a mobility management function corresponding to the RRC idle state. The terminal in the RRC inactive state is connected to a base station, but a data bearer for transmitting and receiving packets may not be set up in the terminal in the RRC inactive state, and functions such as a MAC layer may be deactivated in the terminal in the RRC inactive state. The terminal in the RRC inactive state can transition to the RRC connected state by performing a non-initial access procedure to transmit data. Alternatively, the terminal in the RRC inactive state can transmit restricted data allowed in the RRC inactive state. The restricted data may be data having a restricted size, data having a restricted quality of service, and/or data belonging to a restricted type of service.

From the perspective of the wireless access network, there may be no established connection between the terminal in the RRC idle state and the base station. Connection setup information and/or context information (e.g., RRC context information, AS context information) for the terminal in the RRC idle state may not be stored in the base station and/or the control function block of the wireless access network. The terminal in the RRC idle state may perform an initial access procedure to transition to the RRC connected state. Although the terminal in the RRC idle state attempts to transition to the RRC connected state by performing the initial access procedure, the state of the terminal may transition from the RRC idle state to the RRC inactive state according to the decision of the base station.

A terminal in RRC idle state can transition to RRC inactive state by performing a separate connection procedure defined for initial connection procedure or transition to RRC inactive state. If a limited service is provided to the terminal, the operation state of the terminal can transition from RRC idle state to RRC inactive state. Alternatively, depending on the capability of the terminal, the operation state of the terminal can transition from RRC idle state to RRC inactive state.

The control function block of the base station and/or the wireless access network can set condition(s) for transition to the RRC inactive state by considering one or more of the type, capability, and service (e.g., service currently provided, service to be provided) of the terminal, and can control the transition operation to the RRC inactive state based on the set condition(s). "If the base station allows the transition operation to the RRC inactive state" or "if the transition to the RRC inactive state is set to be possible", the operation state of the terminal can be transitioned from the RRC connected state or the RRC idle state to the RRC inactive state.

FIG. 4 is a conceptual diagram illustrating embodiments of a method for setting a bandwidth part (BWP) in a communication network.

Referring to FIG. 4, a plurality of bandwidth portions (BWP #1-4) may be set within a system bandwidth of a base station. The plurality of bandwidth portions may be set for a transmission operation and/or a reception operation of a terminal. BWP #1-4 may be set to be no greater than a system bandwidth of the base station. The bandwidths of BWP #1-4 may be different from each other, and different subcarrier spacings (SCS) may be applied to BWP #1-4. For example, the bandwidth of BWP #1 may be 10 MHz, and BWP #1 may have an SCS of 15 kHz. The bandwidth of BWP #2 may be 40 MHz, and BWP #2 may have an SCS of 15 kHz. The bandwidth of BWP #3 may be 10 MHz, and BWP #3 may have an SCS of 30 kHz. The bandwidth of BWP #4 may be 20 MHz, and BWP #4 may have an SCS of 60 kHz.

A BWP can be classified into an initial BWP (e.g., a first BWP), an active BWP (e.g., an active BWP), and a default BWP. A terminal can perform an initial connection procedure (e.g., an access procedure) with a base station in the initial BWP. One or more BWPs can be established by an RRC connection establishment message, and one BWP among the one or more BWPs can be established as an active BWP. Each of the terminal and the base station can transmit and receive packets in the active BWP among the established BWPs. Therefore, the terminal can perform a monitoring operation of a control channel for packet transmission and reception in the active BWP.

The terminal can change the operating BWP from the initial BWP to the active BWP or the default BWP. Alternatively, the terminal can change the operating BWP from the active BWP to the initial BWP or the default BWP. The BWP change operation can be performed based on an instruction or a timer of the base station. The base station can transmit information indicating a BWP change to the terminal using at least one of an RRC message, a MAC message (e.g., a MAC CE (control element)), or a PHY message (e.g., a DCI). The terminal can receive the information indicating a BWP change from the base station, and change the operating BWP to a BWP indicated by the received information.

In an NR communication network, if no RA (random access) resource is set in an active UL (uplink) BWP, the terminal may change its operating BWP from the active UL BWP to an initial UL BWP to perform a random access procedure. The operating BWP may be a BWP on which the terminal performs communication (e.g., transmitting and receiving operations of signals and/or channels).

Figure 5 is a conceptual diagram illustrating embodiments of a communication network.

Referring to FIG. 5, the communication network may include a core network and an access network. The core network supporting 4G communication may include an MME, a GW (e.g., an S-GW, a P-GW), etc. The functional block supporting the GW and the MME may be represented by a GW/MME (540). The core network supporting 5G communication may include an AMF, a UPF, a PDN-GW, etc. The functional block supporting the UPF and the AMF may be represented by a UPF/AMF (540). The access network may include a base station (510), a wireless access point (520), a small base station (530), terminals (550-1, 550-2, 550-3), etc. The base station (510) may mean a macro base station. The base station (510) and/or the small base station (530) may be connected to a node (e.g., an end node) of the core network via a backhaul. Nodes in the core network (e.g., end nodes) can be GWs, UPFs, MMEs, AMFs, etc.

The functional separation can be applied to the base station (510) and the small base station (530). In this case, each of the base station (510) and the small base station (530) can include one CU (central unit) and one or more DUs (distributed units). The CU can be a logical node that performs functions of an RRC layer, an SDAP (service data application protocol) layer, and/or a PDCP (packet data convergence protocol) layer. The CU can control the operation of one or more DUs. The CU can be connected to an end node of the core network using a backhaul based on an S1 interface or a backhaul based on an NG interface. The backhaul based on an S1 interface can mean a backhaul in a 4G communication network. The backhaul based on an NG interface can mean a backhaul in a 5G communication network.

A DU may be a logical node that performs functions of the RLC (radio link control) layer, the MAC layer, and/or the PDCP layer. A DU may support one or more cells. A DU may be connected to a CU in a wired or wireless manner using the F1 interface. When a wireless manner is used, the connection between the DU and the CU may be established in an integrated access and backhaul (IAB) manner.

Each of the base station (510) and the small base station (530) may be connected to the wireless access point (520) in a wired or wireless manner using an Fx interface (or fronthaul). In the present disclosure, a base station (e.g., a macro base station, a small base station) may mean a cell, a DU, etc. The wireless access point may mean a transmission and reception point (TRP), a remote radio head (RRH), a relay, or a repeater. The TRP may perform at least one of a downlink transmission function and an uplink reception function. The wireless access point (520) may perform only an RF (radio frequency) function.

Alternatively, the wireless access point (520) may perform RF functions and some functions of the DU (e.g., some functions of the PHY (physical) layer and/or the MAC layer). Some functions of the DU supported by the wireless access point (520) may include sub-functions of the PHY layer, functions of the PHY layer, and/or sub-functions of the MAC layer. The Fx interface between the base station (510, 530) and the wireless access point (520) may be defined differently depending on the function(s) supported by the wireless access point (520).

Each of the "wireless access point (520) of FIG. 5" and the "base stations (110-1, 110-2, 110-3, 120-1, 120-2, 510, 530) of FIGS. 1 and 5" can support downlink communication and/or uplink communication based on OFDM, OFDMA, SC-FDMA, or NOMA. Each of the wireless access point (520) and the base stations (110-1, 110-2, 110-3, 120-1, 120-2, 510, 530) can support a beamforming function using an antenna array in a transmission carrier of a millimeter wave band. In this case, a service through each beam can be provided without interference between beams within the base station. One beam can provide a service for a plurality of terminals.

Each of the wireless access point (520) and the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2, 510, and 530) may support MIMO transmission (e.g., single user (SU)-MIMO, multi user (MU)-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, device to device communication (D2D) (or, proximity services (ProSe), sidelink communication), etc. Here, each of the plurality of terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6, 550-1, 550-2, 550-3) can perform "an operation corresponding to the wireless access point (520) and/or the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2, 510, 530)" and/or "an operation supported by the wireless access point (520) and/or the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2, 510, 530)". For example, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) based on the SU-MIMO scheme, and the fourth terminal (130-4) can receive a signal from the second base station (110-2) by the SU-MIMO scheme. Alternatively, the second base station (110-2) can transmit a signal to the fourth terminal (130-4) and the fifth terminal (130-5) based on the MU-MIMO scheme, and each of the fourth terminal (130-4) and the fifth terminal (130-5) can receive a signal from the second base station (110-2) by the MU-MIMO scheme.

Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can transmit a signal to the fourth terminal (130-4) based on the CoMP scheme, and the fourth terminal (130-4) can receive a signal from the first base station (110-1), the second base station (110-2), and the third base station (110-3) based on the CoMP scheme. Each of the plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) can transmit and receive a signal with terminals (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) within its cell coverage based on the CA scheme. Each of the first base station (110-1), the second base station (110-2), and the third base station (110-3) can coordinate D2D between the fourth terminal (130-4) and the fifth terminal (130-5), and each of the fourth terminal (130-4) and the fifth terminal (130-5) can perform D2D through coordination by each of the second base station (110-2) and the third base station (110-3).

Next, the operation methods of the communication nodes in the communication network will be described. Even if a method (e.g., transmitting or receiving a signal) performed by a first communication node among the communication nodes is described, a second communication node corresponding thereto can perform a method (e.g., receiving or transmitting a signal) corresponding to the method performed by the first communication node. In other words, if the operation of a terminal is described, a base station corresponding thereto can perform an operation corresponding to the operation of the terminal. If the operation of a base station is described, a terminal corresponding thereto can perform an operation corresponding to the operation of the base station.

In a communication network, a GW (e.g., S-GW) may refer to a base station that provides a service to a terminal and an end node of a core network that exchanges packets (e.g., control information, data). In a communication network, an MME may refer to a node (e.g., entity) of a core network that performs a control function in a radio access section (or interface) of a terminal. Each of a backhaul link, a fronthaul link, an xhaul link, a DU, a CU, a BBU block, an S-GW, an MME, an AMF, and a UPF may be referred to by different terms depending on the function of a communication protocol according to a radio access technology (RAT) or the configuration function of a core network.

In order to perform the mobility support function and the radio resource management function, the base station can transmit a synchronization signal (e.g., a synchronization signal/physical broadcast channel (SS/PBCH) block, a synchronization signal block (SSB)) and/or a reference signal. In order to support multiple numerologies, a frame format supporting symbols having different lengths can be configured. In this case, the terminal can perform a monitoring operation of the synchronization signal and/or the reference signal in a frame according to the initial numerology, the default numerology, or the default symbol length. Each of the initial numerology and the default numerology can be applied to a frame format applied to a radio resource for which a UE-common search space is set, a frame format applied to a radio resource for which a control resource set (CORESET) 0 of an NR communication network is set, and/or a frame format applied to a radio resource for which a synchronization symbol burst capable of identifying a cell in an NR communication network is transmitted.

A frame format may mean information (e.g., values of configuration parameters, offset, index, identifier, range, period, interval, duration) for subcarrier spacing, control channels (e.g., CORESET), symbols, slots, and/or reference signals in a radio frame (or subframe). A base station may inform a terminal of the frame format using system information and/or control messages (e.g., dedicated control messages).

A terminal connected to a base station can transmit a reference signal (e.g., an uplink-only reference signal) to the base station using resources configured by the base station. For example, the uplink-only reference signal may include an SRS (sounding reference signal). In addition, a terminal connected to a base station can receive a reference signal (e.g., a downlink-only reference signal) from the base station in the resources configured by the base station. The downlink-only reference signal may be a CSI-RS (channel state information-reference signal), a PT-RS (phase tracking-reference signal), a DM-RS (demodulation-reference signal), etc. Each of the base station and the terminal can perform a beam management operation through monitoring a configured beam or an active beam based on the reference signal.

For example, the base station (510) may transmit a synchronization signal and/or a reference signal so that a terminal located within a communication service area can search for the base station (510) and perform a downlink synchronization maintenance operation, a beam setting operation, or a link monitoring operation. A terminal (550-1) connected to the base station (510) (e.g., a serving base station) may receive physical layer radio resource setting information for connection setting and radio resource management from the base station (510).

The radio resource configuration information of the physical layer may be configuration parameters included in an RRC control message in an LTE communication network and/or an NR communication network. For example, the radio resource configuration information may include PhysicalConfigDedicated, PhysicalCellGroupConfig, PDCCH-Config(Common), PDSCH-Config(Common), PDCCH-ConfigSIB1, ConfigCommon, PUCCH-Config(Common), PUSCH-Config(Common), BWP-DownlinkCommon, BWP-UplinkCommon, ControlResourceSet, RACH-ConfigCommon, RACH-ConfigDedicated, RadioResourceConfigCommon, RadioResourceConfigDedicated, ServingCellConfig, ServingCellConfigCommon, etc.

The wireless resource configuration information may include parameter values such as a configuration period (or allocation period) of a signal (or wireless resource) according to a frame format of a base station (or a transmission frequency), time resource allocation information for transmission, frequency resource allocation information for transmission, transmission time (or allocation time), etc. In order to support multiple numerologies, the frame format of the base station (or the transmission frequency) may mean a frame format having different symbol lengths according to a plurality of subcarrier intervals within one wireless frame. For example, the number of symbols composing each of a mini slot, a slot, and a subframe within one wireless frame (e.g., a frame having a length of 10 ms) may be different from each other.

● Setting information for the base station's transmission frequency and frame format

■ Setting information of transmission frequency: All transmission carriers of the base station (e.g., transmission frequency of cell unit), bandwidth portion (BWP), transmission reference time or time difference information between transmission frequencies of the base station (e.g., transmission period or offset parameter indicating transmission reference time (or time difference) of synchronization signal), etc.

■ Frame format configuration information: Configuration parameters for mini-slots, slots, and subframes with different symbol lengths depending on the subcarrier spacing.

● Configuration information for downlink reference signals (e.g., CSI-RS, common RS, etc.)

■ Common RS configuration information includes configuration parameters such as the transmission period, transmission location, code sequence, and masking sequence (or scrambling sequence) of reference signals commonly applied in the coverage of the base station (or beam).

● Setting information for uplink control signals

■ Reference signal for uplink beam sweeping (or beam monitoring), radio resources (or preamble) for uplink grant-free, etc.

● Configuration information for downlink control channels (e.g., physical downlink control channel (PDCCH))

■ Reference signal for demodulation, beam common reference signal (e.g., reference signal that can be received by all terminals within beam coverage), reference signal for beam sweeping (or beam monitoring), reference signal for channel estimation, etc.

● Configuration information for uplink control channels (e.g., PUCCH (physical uplink control channel))

● Setting information for scheduling request signal

● Configuration information for feedback (e.g., ACK (acknowledgement) or NACK (negative ACK)) transmission resources in the HARQ (hybrid automatic repeat request) procedure

● Number of antenna ports, information about antenna array, beam configuration and/or beam index mapping information for beamforming application

● Configuration information for downlink signals and/or uplink signals (or uplink access channel resources) for beam sweeping (or beam monitoring)

● Configuration information such as beam setup operation, beam recovery operation, beam reconfiguration operation, radio link re-establishment operation, beam change operation at the same base station, received signal of beam that triggers handover procedure to another base station, control timer of the above-mentioned operations, etc.

In a radio frame format that supports different symbol lengths to support multiple numerals, the setting period (or allocation period), time resource allocation information, frequency resource allocation information, transmission time, and/or allocation time of the parameters constituting the above-described information may be information set according to the corresponding symbol length (or subcarrier interval).

In the present disclosure, "Resource-Config information" may be a control message including one or more parameters among radio resource configuration information of a physical layer. In addition, "Resource-Config information" may mean an attribute and/or a configuration value (or a range) of an information element (or parameter) conveyed by the control message. The information element (or parameter) conveyed by the control message may be radio resource configuration information commonly applied throughout the coverage of a base station (or beam) or radio resource configuration information dedicatedly allocated to a specific terminal (or a specific terminal group). The terminal group may include one or more terminals.

The configuration information included in the "Resource-Config Information" may be transmitted through one control message or different control messages depending on the properties of the configuration information. The beam index information may not clearly distinguish between the index of the transmission beam and the index of the reception beam. For example, the beam index information may be expressed using an index (or identifier) of a reference signal mapped or associated with the beam index or a TCI (transmission configuration indicator) state for beam management.

Accordingly, a terminal operating in an RRC connection state can receive a communication service through a beam (e.g., beam pair) set between the terminal and the base station. For example, if a communication service is provided using beam setting (e.g., beam pairing) between the base station and the terminal, the terminal can perform a search operation or a monitoring operation of a wireless channel using a synchronization signal (e.g., SS/PBCH block) and/or a reference signal (e.g., CSI-RS) of a set beam with the base station and a receivable beam. Here, "a communication service being provided through a beam" may mean "a packet is transmitted and received through an activated beam among one or more configured beams." In an NR communication network, "a beam being activated" may mean "a configured TCI state being activated."

The terminal may operate in the RRC idle state or the RRC inactive state. In this case, the terminal may perform a downlink channel discovery operation (e.g., a monitoring operation) using parameter(s) obtained from system information or common Resource-Config information. In addition, the terminal operating in the RRC idle state or the RRC inactive state may attempt a connection using an uplink channel (e.g., a random access channel or a physical layer uplink control channel, etc.). Alternatively, the terminal may transmit control information using the uplink channel.

The terminal can detect or sense a problem of a radio link by performing an RLM (radio link monitoring) operation. Here, "the detection of a problem of the radio link" may mean "the presence of an abnormality in establishing or maintaining physical layer synchronization for the radio link." For example, "the detection of a problem of the radio link" may mean "the detection of a mismatch in physical layer synchronization between the base station and the terminal for a preset period of time." If a problem of the radio link is detected, the terminal can perform a radio link recovery operation. If the radio link is not recovered, the terminal can declare an RLF (radio link failure) and perform a radio link re-establishment procedure.

The procedure for detecting a physical layer problem of a wireless link according to RLM operation, the procedure for recovering a wireless link, the procedure for detecting (or declaring) a failure of a wireless link, and the procedure for re-establishing a wireless link may be performed by functions of layer 1 (e.g., physical layer), layer 2 (e.g., MAC layer, RLC layer, PDCP layer, etc.) and/or layer 3 (e.g., RRC layer) of a wireless protocol configuring a wireless link.

A physical layer of a terminal can monitor a radio link by receiving a downlink synchronization signal (e.g., a primary synchronization signal (PSS), a secondary synchronization signal (SSS), an SS/PBCH block, SSB) and/or a reference signal. The synchronization signal can be interpreted or used as a reference signal. In this case, the reference signal can be a base station common reference signal, a beam common reference signal, or a terminal (or terminal group) specific reference signal (e.g., a dedicated reference signal allocated to a terminal (or a terminal group)). Here, the common reference signal can be used for a channel estimation operation of all terminals located within the coverage (or service area) of a corresponding base station or beam. The dedicated reference signal can be used for a channel estimation operation of a specific terminal or a specific terminal group within the coverage of a corresponding base station or beam.

Accordingly, when a base station or a beam (e.g., a set beam between a base station and a terminal) is changed, a dedicated reference signal for beam management may be changed. The beam may be changed based on the set parameter(s) between the base station and the terminal. A change procedure for the set beam may be required. "Changing a beam in an NR communication network" may mean "changing an index (or identifier) of a TCI state to an index of another TCI state", "newly setting a TCI state", or "changing a TCI state to an activated state". The base station may transmit system information including configuration information of a common reference signal to the terminal. The terminal may acquire the common reference signal based on the system information. In a handover procedure, a synchronization reconfiguration procedure, or a connection reconfiguration procedure, the base station may transmit a dedicated control message including configuration information of a common reference signal to the terminal.

The configuration beam information may include one or more of a configuration beam index (or identifier), a configuration TCI state index (or identifier), configuration information of each beam (e.g., transmission power, beam width, vertical angle, horizontal angle), transmission and/or reception timing information of each beam (e.g., subframe index, slot index, mini slot index, symbol index, offset), reference signal information corresponding to each beam, and a reference signal identifier.

In the present disclosure, the base station may be a base station installed in the air. For example, the base station may be installed on an unmanned aerial vehicle (e.g., a drone), a manned aircraft, or a satellite.

The terminal can receive configuration information of the base station (e.g., identification information of the base station) from the base station through one or more of an RRC message, a MAC message, and a PHY message, and can identify a base station to perform a beam monitoring operation, a wireless access operation, and/or a control (or data) packet transmission/reception operation based on the configuration information.

The result of a measurement operation (e.g., beam monitoring operation) for a beam can be reported via a physical layer control channel (e.g., PUCCH) and/or a MAC message (e.g., MAC CE, control PDU). Here, the result of the beam monitoring operation can be a measurement result for one or more beams (or beam groups). For example, the result of the beam monitoring operation can be a measurement result for beams (or beam groups) according to a beam sweeping operation of the base station.

A base station can obtain a result of a beam measuring operation or a beam monitoring operation from a terminal, and can change a property of a beam or a property of a TCI state based on the result of the beam measuring operation or the beam monitoring operation. A beam can be classified into a primary beam, a secondary beam, a reserve (or candidate) beam, an active beam, and an inactive beam according to the property. A TCI state can be classified into a primary TCI state, a secondary TCI state, a reserve (or candidate) TCI state, a serving TCI state, a set TCI state, an active TCI state, and an inactive TCI state according to the property. The primary TCI state and the secondary TCI state can be assumed as an active TCI state and a serving TCI state, respectively. The reserve (or candidate) TCI state can be assumed as an inactive TCI state or a set TCI state.

The procedure for changing beam (or TCI state) properties can be controlled by the RRC layer and/or the MAC layer. If the procedure for changing beam (or TCI state) properties is controlled by the MAC layer, the MAC layer can notify information about the change of beam (or TCI state) properties to a higher layer. The information about the change of beam (or TCI state) properties can be transmitted to a terminal via a MAC message and/or a physical layer control channel (e.g., PDCCH). The information about the change of beam (or TCI state) properties can be included in downlink control information (DCI) or uplink control information (UCI). The information about the change of beam (or TCI state) properties can be expressed as a separate indicator or field.

The terminal may request a change in the properties of the TCI state based on the result of the beam measurement operation or the beam monitoring operation. The terminal may transmit control information (or feedback information) requesting a change in the properties of the TCI state to the base station using one or more of a PHY message, a MAC message, and an RRC message. The control information (or feedback information, a control message, a control channel) requesting a change in the properties of the TCI state may be configured using one or more of the above-described configured beam information.

A change in the properties of a beam (or TCI state) may mean "changing from an active beam to an inactive beam", "changing from an inactive beam to an active beam", "changing from a primary beam to a secondary beam", "changing from a secondary beam to a primary beam", "changing from a primary beam to a reserve (or candidate) beam", or "changing from a reserve (or candidate) beam to a primary beam". The procedure for changing the properties of a beam (or TCI state) may be controlled by the RRC layer and/or the MAC layer. The procedure for changing the properties of a beam (or TCI state) may be performed through partial cooperation between the RRC layer and the MAC layer.

When multiple beams are allocated, one or more of the multiple beams may be configured as beam(s) for transmitting a physical layer control channel. For example, the primary beam and/or the secondary beam may be used for transmitting and receiving a physical layer control channel (e.g., a PHY message). Here, the physical layer control channel may be a PDCCH or a PUCCH. The physical layer control channel may be used for transmitting one or more of scheduling information (e.g., radio resource allocation information, MCS (modulation and coding scheme) information), feedback information (e.g., CQI (channel quality indication), PMI (precoding matrix indicator), HARQ ACK, HARQ NACK), resource request information (e.g., SR (scheduling request)), a result of a beam monitoring operation for supporting a beamforming function, a TCI state ID, and measurement information for an active beam (or an inactive beam).

The physical layer control channel may be configured to be transmitted through the primary beam of the downlink. In this case, feedback information may be transmitted and received through the primary beam, and data scheduled by the control information may be transmitted and received through the secondary beam. The physical layer control channel may be configured to be transmitted through the primary beam of the uplink. In this case, resource request information (e.g., scheduling request) and/or feedback information may be transmitted and received through the primary beam.

In a procedure for allocating multiple beams (or a procedure for setting a TCI state), allocated (or set) beam indices, information indicating an interval between beams, and/or information indicating whether continuous beams are allocated can be transmitted and received through a signaling procedure between a base station and a terminal. The signaling procedure of beam allocation information can be performed differently depending on status information of the terminal (e.g., moving speed, moving direction, location information) and/or quality of a wireless channel. The base station can obtain status information of the terminal from the terminal. Alternatively, the base station can obtain status information of the terminal through another method.

The radio resource information may include parameter(s) indicating frequency domain resources (e.g., center frequency, system bandwidth, PRB index, number of PBRs, CRB index, number of CRBs, subcarrier index, frequency offset) and parameter(s) indicating time domain resources (e.g., radio frame index, subframe index, transmission time interval (TTI), slot index, mini slot index, symbol index, time offset, period, length, window of transmission interval (or reception interval)). In addition, the radio resource information may further include resource information occupied according to characteristics of a hopping pattern of radio resources, information for beamforming operation (e.g., beam configuration information, beam index), and code sequence (or bit sequence, signal sequence).

The name of the physical layer channel and/or the name of the transport channel may vary depending on the type (or attribute) of data, the type (or attribute) of control information, the direction of transmission (e.g., uplink, downlink, sidelink), etc.

The reference signal for beam (or TCI state) or radio link management can be a synchronization signal (e.g., PSS, SSS, SS/PBCH block), CSI-RS, PT-RS, SRS, DM-RS, etc. The reference parameter(s) for reception quality of the reference signal for beam (or TCI state) or radio link management can be a measurement time unit, a measurement time interval, a reference value (or threshold) indicating the degree of improvement in reception quality, a condition (e.g., reference value) indicating the degree of deterioration in reception quality, etc. Each of the measurement time unit and the measurement time interval can be set in a unit of absolute time (e.g., millisecond, second), TTI, symbol, slot, frame, subframe, scheduling period, operation period of a base station, or operation period of a terminal.

A condition (e.g., a reference value) indicating a degree of change in reception quality can be set as an absolute value (dBm) or a relative value (dB). In addition, the reception quality of a reference signal for beam (or TCI state) or wireless link management can be expressed as reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal-to-noise ratio (SNR), signal-to-interference ratio (SIR), and/or signal-to-interference and noise ratio (SINR).

Meanwhile, in NR communication networks using millimeter frequency bands, flexibility in channel bandwidth operation for packet transmission can be secured based on the BWP (bandwidth part) concept. A base station can set up to four BWPs with different bandwidths to a terminal. BWPs can be set independently in downlink and uplink. In other words, downlink BWPs can be distinguished from uplink BWPs. Each of the BWPs can have different bandwidths as well as different subcarrier spacing.

Measurement operations (e.g., monitoring operations) for beam (or TCI state) or wireless link management can be performed at the base station and/or the terminal. The base station and/or the terminal can perform the measurement operation (e.g., monitoring operation) according to parameter(s) set for the measurement operation (e.g., monitoring operation). The terminal can report the measurement result according to the set parameter(s) for measurement reporting.

If the reception quality of the reference signal according to the measurement result satisfies a preset threshold value (or, reference value) and/or a preset timer condition, the base station may determine whether to perform a beam (or, radio link) management operation, a beam switching operation, or a beam deactivation operation (or, beam activation operation) according to a beam blockage situation. If it is determined to perform a specific operation, the base station may transmit a message that triggers performance of the specific operation to the terminal. For example, the base station may transmit a control message instructing performance of the specific operation to the terminal. The control message may include configuration information of the specific operation.

If the reception quality of the reference signal according to the measurement result satisfies a preset condition (e.g., a reference value, a threshold value) and/or a preset timer condition, the terminal may report the measurement result to the base station. Alternatively, the terminal may transmit to the base station a control message that triggers a beam (or radio link) management operation, a beam switching operation (or a TCI state ID change operation, a property change operation), or a beam deactivation operation (or a beam activation operation) according to a beam blockage situation. The control message may request performance of a specific operation.

A basic procedure for beam (or TCI state) management through wireless link monitoring may include a beam failure detection (BFD) procedure, a beam recovery (BR) request procedure, etc. for the wireless link. Each of "an operation for determining whether to perform the beam failure detection procedure and/or the beam recovery request procedure", "an operation for triggering performance of the beam failure detection procedure and/or the beam recovery request procedure", and "a control signaling operation for the beam failure detection procedure and/or the beam recovery request procedure" may be performed by one or more of a PHY layer, a MAC layer, and an RRC layer.

FIG. 6 is a conceptual diagram illustrating embodiments of a method for providing a service using multiple wireless access points in a communication network.

Referring to FIG. 6, the base stations (611, 612) can provide services to wireless access points (621-1, 621-2, 622-1) within the service area via a wired interface or a wireless interface. The interface between the base station (611) and the wireless access points (621-1, 621-2) within the service area of the base station (611) can be provided in a wired manner or a wireless manner. The interface between the base station (612) and the wireless access point (622-1) within the service area of the base station (612) can be provided in a wired manner or a wireless manner. Functional separation can be applied to the base stations (611, 612). In this case, the base station (611, 612) can be composed of two or more nodes (e.g., CU, DU) that perform wireless protocol functions of the base station (611, 612).

The base station (611, 612) and the wireless access points (621-1, 621-2, 622-1) can provide services to terminals (650, 651-1, 651-2, 651-3, 652-1, 652-2) within each service area via a wireless link (e.g., Uu interface). The transmission frequencies (or frequency bands) of the wireless access points (621-1, 621-2) within the base station (611) can be the same or different. When the wireless access points (621-1, 621-2) use the same frequency, the wireless access points (621-1, 621-2) can operate in the same cell having the same PCI (physical cell ID) or in different cells having different PCIs.

When wireless access points (621-1, 621-2) operate at the same frequency, the wireless access points (621-1, 621-2) can provide a service to the terminal (651-3) in a single frequency network (SFN) manner. The SFN manner may mean "a manner in which one or more wireless access points simultaneously transmit the same data to the terminal using the same frequency." In order to provide a service in the SFN manner, each of the wireless access points (621-1, 621-2) can transmit a downlink channel and/or signal to the terminal (651-3) using the same resource (e.g., physical resource block (PRB)) in the frequency and time domains. The terminal (653-1) can receive a downlink channel and/or signal from each of the wireless access points (621-1, 621-2) using a beam (or radio resource) corresponding to a beam identifier (e.g., a TCI state identifier) of each of the wireless access points (621-1, 621-2). The downlink channel and/or signal may mean at least one of a downlink channel or a downlink signal. The TCI state identifier may be a TCI state ID or a TCI state index.

Wireless access points (621-1, 621-2) operating at the same frequency may not use the SFN scheme. In this case, each of the wireless access points (621-1, 621-2) may transmit a downlink channel and/or signal to the terminal (651-3) using different resources (e.g., PRBs) in the frequency and time domains. The terminal (653-1) may receive a downlink channel and/or signal from each of the wireless access points (621-1, 621-2) using a beam (or radio resource) corresponding to a beam identifier (e.g., TCI state identifier) of each of the wireless access points (621-1, 621-2).

The wireless access points (621-1, 621-2) may have different PCIs. In other words, the wireless access points (621-1, 621-2) may operate in different cells. "The wireless access points (621-1, 621-2) operate in different cells" may mean that "the base station (611) includes two or more cells having different PCIs, and each of the wireless access points (621-1, 621-2) is a subnode (or, wireless access point) of a cell." Alternatively, “wireless access points (621-1, 621-2) operating as different cells” may mean “two or more cells having different PCIs exist within one DU included in a base station (611) to which functional separation is applied, and each of the wireless access points (621-1, 621-2) is a lower node (or, wireless access point) of the cell.”

When wireless access points (621-1, 621-2) belong to different cells within a base station or a DU of the base station, a service for a terminal that does not support carrier aggregation function (e.g., a terminal in an RRC connected state) can be provided from one wireless access point.

A base station can provide a service to a terminal by using one or more cells or one or more wireless access points. A base station to which functional separation is applied can include one CU and multiple DUs, and each of the multiple DUs can provide a service to a terminal by using one or more cells or one or more wireless access points.

In the present disclosure, a method for providing a service to a terminal in an RRC connected state by using a machine learning (e.g., artificial intelligence) function, a method for determining (e.g., selecting) a cell and/or a wireless access point on which a terminal in an RRC inactive state camps by using a machine learning (e.g., artificial intelligence) function, a method for signaling information (e.g., measurement, reporting, preference information) related to the machine learning (e.g., artificial intelligence) function, a mobility control method using a machine learning (e.g., artificial intelligence) function, etc. will be proposed.

Communication nodes (e.g., base stations, eNBs, gNBs, cells, Non-terrestrial Network (NTN) nodes, Integrated Access and Backhaul (IAB) nodes, and wireless access points (e.g., TRPs, RRHs, relays, repeaters)) may support functional separation, carrier aggregation, dual connectivity, multi-RAT (radio access technology) connectivity, and/or redundant transmission. The terminal may mean various types of terminals. For example, the terminal may be a wearable device, an Internet of Things (IoT) device, a portable terminal device, a device installed in a vehicle, a head-mounted device (HMD), etc. Machine learning functions may be applied to maintain a wireless link in a communication network, control connection, support mobility functions (e.g., mobility control), establish a communication node, release a communication node, and/or change a communication node.

Figures 7a, 7b, and 7c are conceptual diagrams illustrating the configuration of a base station that provides communication services to terminals.

Referring to FIGS. 7a, 7b, and 7c, a base station (701, 711) to which functional separation is not applied may include one or more cells (705-1, 705-2, ..., 705-n, 715-1, 715-2, ..., 715-n) and/or one or more TRPs (703-1, 703-2, ..., 703-m, 713-1, ..., 713-m). Each of n and m may be a natural number. In a base station (701, 711) to which functional separation is not applied, there may exist cells (705-1, ..., 705-n, 715-2, ..., 715-n) including one or more TRPs (703-1, 703-2, ..., 703-m, 713-1, ..., 713-m) and cells (705-2, 715-1) not including TRPs (703-1, 703-2, ..., 703-m, 713-1, ..., 713-m). A cell may include one or more TRPs. Alternatively, a cell may not include a TRP. A terminal (704-1, 704-2) may form a RL (radio link) with a cell and/or a TRP.

A base station (721, 731) to which functional separation is applied may include a central unit (CU) (722, 732) and a distributed unit (DU) (726, 736). The DU (726, 736) may include one or more cells (725-1, 725-2, ..., 725-n, 735-1, 735-2, 735-3, ..., 735-n) and/or one or more TRPs (723-1, 723-2, ..., 723-m, 733-1, 733-2, ..., 733-(m-1), 733-m). In FIGS. 7b and 7c, DUs (726, 736) include cells and/or TRPs, but not all functions of the cells and/or TRPs may be implemented in DUs (726, 736). The embodiments of FIGS. 7b and 7c may illustrate that hierarchies for DUs (726, 736) and cells (or TRPs) in a communication network are distinguished. One or more cells (725-1, 725-2, ..., 725-n, 735-1, 735-2, 735-3, ..., 735-n) included in DUs (726, 736) may perform functions below an RLC (radio link control) layer in a wireless protocol layer (e.g., functions of an RLC layer, functions of a MAC (medium access control) layer, functions of a PHY (physical) layer).

In a base station (721, 731) to which functional separation is applied, there may exist cells (725-1, ..., 725-n, 735-2, 735-3, ..., 735-n) including one or more TRPs (723-1, 723-2, ..., 723-m, 733-1, 733-2, ..., 733-(m-1), 733-m) and cells (725-2, 735-1) that do not include TRPs (723-1, 723-2, ..., 723-m, 733-1, 733-2, ..., 733-(m-1), 733-m). A cell may include one or more TRPs. Or, a cell may not include a TRP. Terminals (704-3, 704-4) can form cells and/or TRPs and RLs.

Multiple TRPs included in a single cell can have the same PCI (physical cell identifier). In other words, the same PCI can be applied to multiple TRPs included in a single cell. Each TRP within a cell can be distinguished by a TRP index (or ID (identifier)). TRPs belonging to different cells can have different PCIs.

A base station can provide a service (e.g., a communication service) to terminals (704-1, 704-2, 704-3, 704-4) within a coverage area of a cell and/or TRP by using a wireless link (e.g., RL1, RL2). If CA (carrier aggregation) is not set for terminals (704-1, 704-2, 704-3, 704-4) in an RRC connection state, the terminals (704-1, 704-2, 704-3, 704-4) can perform communication by using one cell (e.g., PCell (primary cell)) and one wireless link (e.g., RL1). The wireless link may mean a wireless channel. When CA is set for terminals (704-1, 704-2, 704-3, 704-4) in RRC connection state, the terminals (704-1, 704-2, 704-3) can perform communication using a wireless link for PCell (e.g., RL1) and a wireless link for SCell (secondary cell) (e.g., RL2).

TRPs may belong to the same cell or different cells. TRPs belonging to the same cell may have the same PCI, and TRPs belonging to different cells may have different PCIs. The same PCI may be applied to TRPs (703-1, 703-2) belonging to the same cell, and the same PCI may be applied to TRPs (723-1, 723-2) belonging to the same cell. TRPs belonging to different cells may operate in the same frequency band or different frequency bands. TRPs operating in different frequency bands may be TRPs having different PCIs (e.g., TRPs belonging to different cells).

If DC (dual connectivity) is not set for a terminal in an RRC connection state, the terminal can set up an RRC connection with one base station, and the terminal can receive a service from one base station. If CA is not set for the terminal, the terminal can receive a service from one cell (e.g., PCell) through RL1 of FIG. 7a and/or FIG. 7b. A terminal in an RRC connection state where DC is not set can perform a MAC layer function using one MAC entity.

In a communication network composed of various communication nodes (e.g., satellites, airborne vehicles, etc.), a mobility control/management function based on machine learning (e.g., artificial intelligence) can be introduced by considering the status of a mobile device (e.g., a wireless terminal mounted on a mobile device) and/or a terminal in an access link between a terminal and communication node(s). The mobile device may include an unmanned aerial vehicle, a train, a ship, an automobile, etc. In order to improve service performance through connection control, management and recovery of a wireless link, and/or setting and change of communication nodes, a mobility control/management function based on machine learning (e.g., artificial intelligence) can be considered. The operation of a base station and/or a terminal, a signaling method, etc. for collecting and/or reporting learning information, parameters, etc. required in a functional block (e.g., entity) to which machine learning (e.g., artificial intelligence, learning model) is applied will be described.

A communication node may support functional separation, carrier aggregation, dual connectivity, multi-RAT connectivity, and/or redundant transmission. The communication node may be at least one of a base station (e.g., eNB, gNB), a cell, an NTN node, an IAB node, or a wireless access point (e.g., TRP, RRH, relay, repeater). The communication node may mean a terminal depending on the context. The terminal may be at least one of a UE, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, an IoT device, an onboard device (e.g., a mounted module/device/terminal or an on board device/terminal), a wearable device, or a head-mounted device (HMD).

Figure 8 is a conceptual diagram illustrating an embodiment of service provision and mobility function support in air nodes and ground nodes.

Referring to FIG. 8, terminals (804-1, 804-2) may be located in an air node service area (802-1) of an air node (801) and may receive services from the air node (801). The air node (801) may be installed on a satellite or an airborne vehicle. Terminals (804-3, 804-4, 804-5) located in a ground node service area (802-2) may receive services from ground nodes (803-1, 803-2, 803-3, 803-4). The air node service area (802-1) may not overlap with the ground node service area (802-2). Alternatively, the air node service area (802-1) may overlap with the ground node service area (802-2).

The terminals (804-1, 804-2) may belong to the air node service area (802-1) or the ground node service area (802-2) depending on their movement. When the terminals (804-1, 804-2) belong to the air node service area (802-1), the terminals (804-1, 804-2) can receive services from the air node (801). When the terminals (804-1, 804-2) belong to the ground node service area (802-2), the terminals (804-1, 804-2) can receive services from the ground nodes (803-1, 803-2, 803-3, 803-4). The movement path of the terminal (804-1) may be 806-1 illustrated in FIG. 8, and the movement path of the terminal (804-2) may be 806-2 illustrated in FIG. 8. There may be a terminal (804-6) that does not belong to the air node service area (802-1) and the ground node service area (802-2). The terminal (804-6) may not receive services from the air node (801) and the ground nodes (803-1, 803-2, 803-3, 803-4). In the above-described communication system (e.g., a communication network), depending on the connection status of the terminal and/or the service being provided to the terminal, a method for minimizing power consumption in the communication node and the terminal, a method for efficiently managing wireless resources, a method for controlling connection of the terminal, and/or a method for controlling mobility of the terminal may be required.

A terminal (804-1) and/or an air node (801) moving along a movement path (807-1) can predict (e.g., estimate) a time required for the terminal (804-1) to move to edge point 1 (edge point of service or edge line of service) (806-1) (hereinafter, referred to as “time required 1”), a time required for the terminal (804-1) to arrive at edge point 1 (806-1) (hereinafter, referred to as “arrival time 1”), and/or a distance (hereinafter, referred to as “distance 1”) from the location of the terminal (804-1) to edge point 1 (806-1). For example, based on measurement information (e.g., report information) of periodic/aperiodic wireless channel quality between the air node (801) and the terminal (804-1), position report information (e.g., positioning report information) of the terminal (804-1), a moving speed of the terminal (804-1), and/or movement information (e.g., movement trajectory information) of the terminal (804-1), the air node (801) and/or the terminal (804-1) can predict (e.g., estimate) the required time 1, the arrival time 1, and/or the distance 1. The required time 1, the arrival time 1, and/or the distance 1 may be movement status information, and the movement status information may be information about a time point when the terminal (804-1) leaves the air node service area (802-1).

The terminal (804-1) can measure terminal location information and report the terminal location information to the air node (801) periodically or aperiodically. The air node (801) can obtain terminal location information from the terminal (804-1). The terminal location information of the terminal (804-1) can be location information estimated based on global positioning system (GPS) information, a reference signal (e.g., a reference signal for positioning), and/or location information obtained through a built-in sensor. The air node (801) and the terminal (804-1) can predict (e.g., estimate) the required time 1, the arrival time 1, and/or the distance 1 based on the above-described information. The air node (801) can transmit a prediction result (e.g., an estimation result) to the terminal (804-1). The terminal (804-1) can receive the prediction result from the air node (801). The predicted results may include time taken 1, arrival time 1, and/or distance 1.

The aerial node (801) can predict (e.g., estimate) the time required for the terminal (804-1) to move to boundary point 2 (806-2) (hereinafter, referred to as “required time 2”), the time required for the terminal (804-1) to arrive at boundary point (806-2) (hereinafter, referred to as “arrival time 2”), and/or the distance (hereinafter, referred to as “distance 2”) from the current location of the terminal (804-1) to boundary point 2 (806-2), considering the movement status information of the terminal (804-1). The boundary point 2 (806-2) can be a point where the ground node service area (802-2) starts. The aerial node (801) can transmit the prediction result (e.g., the estimation result) to the terminal (804-1). The terminal (804-1) can receive the prediction result from the aerial node (801). The prediction result may include a time required 2, an arrival time 2, and/or a distance 2. The prediction result may be information about when the terminal (804-1) enters the ground node service area (802-2).

For a terminal in an RRC connection state, the air node (801) can transmit configuration information (hereinafter, “AI (Artificial Intelligence)/ML (Machine Learning)-mobility configuration information”) to the terminal for supporting a mobility control/management learning model function by using a dedicated control message (e.g., an RRC message, a MAC layer control message (e.g., MAC CE), and/or a physical layer control message (e.g., DCI)). The terminal can receive the AI/ML-mobility configuration information from the air node (801). The AI/ML-mobility configuration information for a terminal in an RRC connection state can include at least one of a current location of the terminal, a travel time 1, an arrival time 1, a distance 1, a travel time 2, an arrival time 2, a distance 2, an event condition set for mobility control/management based on a learning model, a geographical location (e.g., a geographic location, a reference point) set for mobility control/management based on a learning model, or location information of a neighboring communication node.

For a terminal in RRC inactive state or RRC idle state, the air node (801) may transmit AI/ML-mobility configuration information to the terminal using system information and/or terminal state transition control messages (e.g., RRC connection reconfiguration message, RRC connection release message, and/or RRC resume message). The AI/ML-mobility configuration information for a terminal in RRC inactive state or RRC idle state may include at least one of: duration 1, arrival time 1, distance 1, duration 2, arrival time 2, distance 2, an event condition set for learning model-based mobility control/management, a geographical location set for learning model-based mobility control/management (e.g., a geographic location, a reference point), or location information of a neighboring communication node.

The AI/ML-mobility configuration information may further include at least one of parameters for preparing a learning model function or operation of a communication node and/or a terminal, configuration parameters of the learning model, condition parameters of the learning model, execution condition parameters, input parameters for performing a learning model function, collection parameters for performing a learning model function, or execution instruction information of the learning model. The execution instruction information of the learning model may include at least one of an identifier of the learning model, an input parameter set identifier of the learning model, an execution condition identifier, or an execution identifier. A control message transmitting identification information of the learning model function, execution condition information of the learning model function, operation preparation information, and/or execution instruction between the communication node and the terminal may be transmitted including the above-described identifier. Alternatively, only the above-described identifier may be transmitted.

When the terminal (804-1) is in an RRC connection state with the air node (801) (for example, when the terminal (804-1) is receiving a service from the air node (801), the terminal (804-1) and/or the air node (801) can complete the service before the terminal (804-1) arrives at the boundary point 1 (806-1). The arrival of the terminal (804-1) at the boundary point 1 (806-1) can be determined based on the AI/ML-mobility configuration information. The terminal (804-1) and/or the air node (801) can prepare for the terminal (804-1) to enter the ground node service area (802-2) and resume the service. The time when the terminal (804-1) enters the ground node service area (802-2) can be determined based on the AI/ML-mobility configuration information. For the above operation, the operating state of the terminal (804-1) can be transitioned to the RRC idle state or the RRC inactive state.

FIG. 9 is a conceptual diagram illustrating a mobility control operation according to a change in wireless channel quality in the movement path of the terminal (804-1) of FIG. 8.

Referring to FIG. 9, the terminal (804-1) may arrive at the boundary point 1 (806-1, 903) at the predicted time (903) signaled by the air node (801). In this case, the terminal (804-1) may determine whether it is located within the air node service area (802-1). The predicted time (903) may be indicated or confirmed by AI/ML-mobility configuration information. For example, the terminal (804-1) may measure the wireless channel quality for the air node (801). If the measured wireless channel quality is less than a reference condition (e.g., a condition for determining whether the terminal (804-1) is located within the air node service area (802-1), the terminal (804-1) may determine that it has left the air node service area (802-1). In other words, the terminal (804-1) can be determined to be in an out of service area (OoS) state for the air node service area (802-1). The reference condition may be a cell/node detection criterion (901) for a cell search procedure, a cell camping condition (911), and/or a reference value for determining an OoS state.

The terminal (804-1) may arrive at the boundary point 1 (806-1, 903) at a time (e.g., T1 (903-1)) before the predicted time (903) signaled by the air node (801). Alternatively, the terminal (804-1) may arrive at the boundary point 1 (806-1) at a time (e.g., T2 (903-2)) after the predicted time (903) signaled by the air node (801). Regardless of the time of arrival at the boundary point 1 (806-1), the terminal (804-1) may determine whether it is located within the air node service area (802-1) based on the above-described method. When the terminal (804-1) is in an OoS state for the air node service area (802-1), the terminal (804-1) can measure (e.g., calculate, determine) at least one of location information, quality information of a wireless channel, an event condition set for mobility control, movement status information of the terminal, difference information (e.g., deviation information) between information about boundary point 1 (806-1, 903) obtained from the air node (801) (e.g., location, time, distance) and information about boundary point 1 (806-1, 903) measured (e.g., calculated) by the terminal (804-1), movement time, required time, or movement distance, and generate parameters for a mobility control/management learning model (hereinafter, referred to as “AI/ML-mobility parameters”) based on the measured information. In other words, the terminal (804-1) can store the measured information as AI/ML-mobility parameters.

The movement time, the required time, and the movement distance may be the movement time, the required time, and the movement distance between the occurrence times (e.g., occurrence points) of the events set for mobility control/management based on a learning model, respectively. The movement time, the required time, and/or the movement distance for AI/ML-mobility parameters may be measured information (e.g., calculated information) based on the movement time, required time, and/or the movement distance between locations for geographical locations (e.g., geographic locations, reference points), communication nodes, and/or terminals set for mobility control/management based on a learning model, respectively. The distance information may be expressed in the form of a measured distance between locations (e.g., points). Alternatively, the distance information may be expressed in the form of a relative distance from a reference location (e.g., a reference point).

The terminal (804-1) can move within the OoS. The terminal (804-1) can periodically or aperiodically measure (e.g., calculate) the movement time, movement distance, and/or movement direction from boundary point 1 (806-1 of FIG. 8) to boundary point 2 (806-2, 904), and additionally generate AI/ML mobility parameters based on the measured information. The terminal (804-1) can update the AI/ML mobility parameters based on the measured information. Based on the AI/ML-mobility configuration information for a terminal in RRC inactive state or RRC idle state, the terminal (804-1) can reduce unnecessary power consumption of the terminal (804-1) by deactivating a cell search function (e.g., a cell search procedure) while moving from a recognized service termination point based on trajectory information (e.g., history information) of the air node (801) or a boundary point 1 (806-1, 903) of the air node service area (802-1) to boundary point 2 (806-2, 904). The terminal (804-1) can perform the cell search procedure by activating the cell search function based on "turning/changing of its own moving direction" and/or "updated AI/ML-mobility parameters."

The terminal (804-1) can reach the ground node service area (802-2) through the boundary point 2 (806-2, 904) on its movement path (807-1). The terminal (804-1) can move from "the service area of the macro node (803-1) → the service area of the wireless access point (803-2) → the service area of the small node (803-4) → the service area of the macro node (803-1)". The terminal (804-1) can pass through boundary area 3 (806-3, 905), boundary area 4 (806-4, 906), and boundary area 6 (806-6, 907) within the ground node service area (802-2). The boundary area may mean an area where two or more service areas overlap.

The terminal (804-1) can recognize that the terminal (804-1) is close to the boundary point 2 (806-2, 904) based on the learning model function based on the AI/ML-mobility setting information acquired from the air node (801). In this case, the terminal (804-1) can activate the cell search function. When the cell search function is activated, the terminal (804-1) can measure the wireless channel quality of the macro node (803-1) by performing a cell search procedure. The terminal (804-1) can camp on the macro node (803-1) at a time point (911-1) when the wireless channel quality of the macro node (803-1) is equal to or higher than the cell camping condition (911). The terminal (804-1) can perform a mobility procedure with the macro node (803-1). The mobility procedure may include a cell switching procedure, a beam switching procedure, an access procedure, a handover procedure, a cell selection procedure, a cell reselection procedure, a dual connectivity procedure, and/or a multi-RAT connectivity procedure. A terminal in RRC inactive state or RRC idle state may receive AI/ML-mobility configuration information from the macro node (803-1) on which it has camped.

In order to resume a suspended service or receive a new service, the terminal may perform an access procedure to transition to an RRC connected state. The terminal in the RRC connected state may receive AI/ML-mobility configuration information from a serving cell through a dedicated control message. In other words, the dedicated control message transmitted by the serving cell may include AI/ML-mobility configuration information. In the ground node service area (802-2), the AI/ML-mobility configuration information for mobility control/management based on a learning model function may include information on a boundary area between communication nodes and/or adjacent nodes. The information on the boundary area may include at least one of a learning model-based beam/cell switching event condition, beam/cell switching predicted location information (e.g., predicted point information, predicted area information), a condition for determining whether the terminal enters the boundary area, a time required to reach the boundary area, an arrival time in the boundary area, distance information for the boundary area, a stay time in the boundary area according to the mobility status information of the terminal (e.g., predicted stay time), or a passage time in the boundary area according to the mobility status information of the terminal (e.g., predicted passage time). The distance information may be expressed in the form of a measured distance between locations (e.g., points). Alternatively, the distance information may be expressed in the form of a relative distance from a reference location (e.g., a reference point). The cell switching procedure may mean a handover procedure. In other words, the cell switching procedure may mean a procedure for changing a serving cell (e.g., a serving communication node) to a target cell (e.g., a target communication node).

The terminal (804-1) and/or the communication node (803-1, 803-2, 803-3) can determine whether the terminal (804-1) enters the boundary area (806-3, 806-4, 806-6) based on the learning model according to the above-described method. In other words, the terminal (804-1) and/or the communication node (803-1, 803-2, 803-3) can estimate (e.g., predict) whether the terminal (804-1) enters the boundary area (806-3, 806-4, 806-6) based on channel quality, time, and/or distance information.

The terminal (804-1) and/or the communication nodes (803-1, 803-2, 803-3) may perform the connection control procedure and/or the mobility management procedure before the terminal (804-1) enters the boundary area (806-3, 806-4, 806-6). In other words, the terminal (804-1) may perform the mobility procedure before a time (e.g., a predicted time) at which the terminal (804-1) is predicted to enter the boundary area (806-3, 806-4, 806-6). Alternatively, the terminal (804-1) and/or the communication nodes (803-1, 803-2, 803-3) may perform the connection control procedure and/or the mobility management procedure at the same time as the terminal (804-1) enters the boundary area (806-3, 806-4, 806-6). In other words, at a time point (e.g., a predicted time) when the terminal (804-1) is predicted to enter the boundary area (806-3, 806-4, 806-6), the terminal (804-1) may perform a mobility procedure. For example, the terminal (804-1) in an RRC inactive state may change the camping node to the corresponding communication node at the same time as entering the boundary area. The terminal (804-1) in an RRC connected state may perform a changing procedure of the serving communication node (e.g., a switching procedure) or an additional connection procedure of the serving communication node (e.g., a dual connection procedure or a multi-RAT connection procedure) before or at the same time as entering the boundary area.

For example, before arriving at the boundary area 3 (806-3, 905), the terminal (804-1) may periodically or aperiodically measure (e.g., calculate) the location of the terminal (804-1), the quality of the wireless channel of the communication node(s), the synchronization information of the communication node(s), the information of the preferred candidate beam/target beam, the information of the candidate cell/target cell/communication node, the distance information to the boundary area 3 (806-3, 905), and/or the arrival prediction time information of the boundary area 3 (806-3, 905), and may add, generate, or update AI/ML-mobility parameters based on the measured information, and may report the AI/ML-mobility parameters to the macro node (803-1), which is a serving cell. In other words, the AI/ML-mobility configuration information may be updated based on the measurement information of the terminal (804-1). Synchronization information of communication node(s) may mean synchronization information (e.g., synchronization time difference) between a serving cell and adjacent communication node(s) for adjusting transmission timing of an uplink physical channel of a terminal, or synchronization information (e.g., synchronization time difference) between adjacent communication nodes.

The terminal (804-1) can transmit AI/ML-mobility parameter and/or AI/ML-mobility report information for supporting learning model function to the macro node (803-1). The macro node (803-1) can receive AI/ML-mobility parameter and/or AI/ML-mobility report information for supporting learning model function from the terminal (804-1). The macro node (803-1) can transmit radio resource configuration information (e.g., radio resource configuration information for the terminal (804-1)) allocated by the wireless access point (803-2), which is a target communication node determined in the boundary area 3 (806-3, 905), to the terminal (804-1). The terminal (804-1) can receive radio resource configuration information allocated by the wireless access point (803-2) from the macro node (803-1). In other words, the terminal (804-1), the macro node (803-1) which is a serving cell, and/or the wireless access point (803-2) which is a target cell can exchange control information (e.g., AI/ML-mobility configuration information, AI/ML-mobility parameters, and/or AI/ML-mobility reporting information) in advance for supporting the learning model function.

A terminal (804-1) that has entered boundary area 3 (806-3, 905) can receive downlink scheduling information and/or timing information (e.g., uplink physical layer timing adjustment information) from a wireless access point (803-2) without performing an uplink synchronization setup procedure (e.g., a random access procedure) with the wireless access point (803-2), which is a target cell. The downlink scheduling information and/or uplink physical layer timing adjustment information can be transmitted and received in resources indicated by radio resource setup information pre-allocated by the wireless access point (803-2). The terminal (804-1) that has entered the boundary area 3 (806-3, 905) can transmit necessary information to the target cell by using the pre-allocated uplink resources (e.g., the radio resources of the radio access point (803-2) indicated by the macro node (803-1)) without performing an uplink synchronization procedure (e.g., a random access procedure) with the radio access point (803-2). When the cell switching procedure is performed from the macro node (803-1), which is the serving cell, to the radio access point (803-2), which is the target cell, based on the learning model, the terminal (804-1) can perform the cell switching procedure without performing the "step of the terminal (804-1) transmitting a message requesting cell switching to the serving macro node (803-1)" and/or the "step of the terminal (804-1) receiving a control message instructing cell switching to be performed from the serving macro node (803-1) to the target radio access point (803-2)". In other words, a terminal (804-1) that has entered boundary area 3 (806-3, 905) can perform or complete a cell switching procedure by transmitting an uplink channel to a target wireless access point (803-2) and/or receiving a downlink channel from the target wireless access point (803-2) without performing any procedure for transmitting and receiving a control message for a cell switching procedure (e.g., support of a mobility procedure) with a serving macro node (803-1).

In order to establish uplink synchronization between a terminal (804-1) that has entered boundary area 3 (806-3, 905) and a target wireless access point (803-2), the target wireless access point (803-2) can transmit uplink physical channel transmission timing adjustment information to the terminal (804-1). For example, based on the support of a learning model-based mobility control/management function, the target wireless access point (803-2) can directly transmit uplink physical channel transmission timing adjustment information to the terminal (804-1) that has entered boundary area 3 (806-3, 905) by using synchronization information of communication node(s) received from the terminal and/or serving macro node (803-1). The terminal (804-1) can receive uplink physical channel transmission timing adjustment information from the target wireless access point (803-2). Alternatively, based on the support of the learning model-based mobility control/management function, the serving macro node (803-1) may transmit uplink physical channel transmission timing adjustment information for the target wireless access point (803-2) to the terminal (804-1) using the synchronization information of the communication node(s) received from the terminal. The terminal (804-1) may receive the uplink physical channel transmission timing adjustment information from the serving macro node (803-1).

Based on the above-described learning model-based mobility control/management method, a terminal in an RRC inactive state or an RRC idle state can camp on a target radio access point (803-2) by performing a cell (re)selection procedure in a boundary area 3 (806-3, 905). The cell (re)selection procedure may mean a cell selection procedure and/or a cell re-selection procedure. The terminal may add, generate, and/or store AI/ML-mobility parameters based on previous AI/ML-mobility parameters acquired (e.g., stored) based on AI/ML-mobility configuration information and/or information measured (e.g., calculated) in a cell (re)selection procedure or cell camping procedure for the boundary area (e.g., radio channel quality (e.g., radio channel quality of a camping cell), camping time, location information of the terminal, movement path information, movement time information, movement distance information, and/or difference information (e.g., error, deviation) for movement status information). The above terminal can store the AI/ML-mobility parameters in the learning model. In other words, the terminal can update the AI/ML-mobility setting information.

Based on the above-described learning model-based mobility control/management method, a terminal in an RRC connection state can perform a cell switching procedure from a serving macro node (803-1) to a target radio access point (803-2) in boundary area 3 (806-3, 905). The terminal can add, generate, and/or store AI/ML-mobility parameters based on previous AI/ML-mobility parameters acquired (e.g., stored) based on AI/ML-mobility configuration information and/or information measured (e.g., calculated) in the cell switching procedure for the boundary area (e.g., information on a serving cell, information on a target cell, radio channel quality of the serving cell, radio channel quality of the target cell, time required for the cell switching procedure, location information of the terminal, movement path information, movement time information, movement distance information, and/or difference information (e.g., error, deviation) for movement status information). The terminal can store the AI/ML-mobility parameters in a learning model. In other words, the terminal can update AI/ML-mobility setting information.

In the boundary area 4 (806-4, 906) and/or the boundary area 6 (806-6, 907), the cell switching procedure can be performed based on the above-described learning model-based mobility control/management method and procedure. When the learning model-based mobility control/management function operates, in order to prevent the performance of an unnecessary mobility procedure (e.g., a cell switching procedure), the communication node and/or the terminal can request the suspension of the mobility procedure (e.g., a cell switching procedure) in the boundary area, or instruct the suspension (or holding) of the mobility procedure (e.g., a cell switching procedure). Alternatively, the communication node and/or the terminal may not perform the mobility procedure (e.g., a cell switching procedure) in the boundary area. For example, the mobility status of the terminal, the load status of the network, and/or the quality status of the wireless channel can be identified based on stored data or the inference result of the learning model, and the communication node and/or the terminal can temporarily suspend the provision of a service based on the identified status. Alternatively, the communication node and/or the terminal may determine that continuous service provision is possible without performing a mobility procedure (e.g., a cell switching procedure) by changing the service performance/service speed (e.g., data transmission speed, MCS (modulation and coding scheme) level) based on the verified status. In this case, the communication node and/or the terminal may request or instruct the suspension of the mobility procedure (e.g., the cell switching procedure) in the mobility control/management procedure. Alternatively, the communication node and/or the terminal may not perform the mobility procedure (e.g., the cell switching procedure). A request to stop a mobility procedure (e.g., a cell switching procedure), an instruction to stop a mobility procedure (e.g., a cell switching procedure), and/or non-performance of a mobility procedure (e.g., a cell switching procedure) may be applied only during a preset time point (e.g., a preset time interval) when a preset condition is met.

FIG. 10 is a conceptual diagram illustrating a mobility control operation according to a change in wireless channel quality in the movement path of the terminal (804-2) of FIG. 8.

Referring to FIG. 10, a terminal (804-2) moving along a movement path (807-2) of FIG. 8 may move from a ground node service area (802-2) (e.g., a service area of a small node (803-4)) to an air node service area (802-1). In other words, the terminal (804-2) may pass through "boundary area 7 (806-7, 1003) → boundary area 5 (806-5, 1004) → boundary area 4 (806-4, 1005) → boundary area 3 (806-3, 1006)".

Based on the function support method of the learning model described above, a terminal in an RRC inactive state or an RRC idle state can camp on a small node (803-4) within a ground node service area (802-2). The terminal can receive AI/ML-mobility configuration information from the small node (803-4). A terminal in an RRC connection state that is already receiving a service from the small node (803-4), a terminal that has transitioned to an RRC connection state to resume a suspended service, and/or a terminal that has transitioned to an RRC connection state to receive a new service can receive AI/ML-mobility configuration information from the small node (803-4) which is a serving cell through a dedicated control message. In other words, the serving small node (803-4) can transmit a dedicated control message including the AI/ML-mobility configuration information to the terminal.

Based on the above-described method, the terminal (804-2) and/or the communication nodes (803-1, 803-2, 803-3, 803-4) can estimate (e.g., predict) whether the terminal (804-2) enters boundary area 7 (806-7), boundary area 5 (806-5), boundary area 4 (806-4), and/or boundary area 3 (806-3) in the moving path (807-2) by using a learning model based on channel quality, time information, distance information, etc. The connection control procedure and/or the mobility management procedure may be performed before the terminal (804-2) arrives at the boundary area. Alternatively, the connection control procedure and/or the mobility management procedure may be performed simultaneously with the terminal (804-2) entering the boundary area. The connection control procedure and/or the mobility management procedure may be collectively referred to as a mobility procedure. For example, a terminal (804-2) in an RRC inactive state can perform a camping cell change procedure for the corresponding communication node at the same time as entering the boundary areas (806-7, 806-5, 806-4, and 806-3). A terminal (804-2) and/or a communication node (803-1, 803-2, 803-3, 803-4) in an RRC connected state can perform a changing procedure of a serving communication node (e.g., a switching procedure, a mobility procedure) or an additional connection procedure of a serving communication node (e.g., a dual connection procedure, a multi-RAT connection procedure) before the terminal (804-2) enters the boundary areas (806-7, 806-5, 806-4, 806-3). Alternatively, the terminal (804-2) and/or the communication node (803-1, 803-2, 803-3, 803-4) in the RRC connection state may perform a changing procedure of the serving communication node (e.g., a switching procedure, a mobility procedure) or an additional connection procedure of the serving communication node (e.g., a dual connection procedure, a multi-RAT connection procedure) at the same time that the terminal (804-2) enters the boundary area (806-7, 806-5, 806-4, 806-3).

Based on the above-described method, before reaching the boundary area 7 (806-7, 1003), the terminal (804-2) can periodically or aperiodically measure (e.g., calculate) the location of the terminal (804-2), the quality of the wireless channel of the communication node(s), the synchronization information of the communication node(s), the information of the preferred candidate beam/target beam, the information of the candidate cell/target cell/communication node, the distance information to the boundary area 7 (806-7, 1003), and/or the arrival prediction time information of the boundary area 7 (806-7, 1003), and can add, generate, and/or update the AI/ML-mobility parameters based on the measured information, and can report the AI/ML-mobility parameters to the small node (803-4) which is a serving cell. The small node (803-4) can receive AI/ML-mobility parameters from the terminal (804-2).

The terminal (804-2) can transmit AI/ML-mobility reporting information for supporting AI/ML-mobility parameters and/or learning model functions to the small node (803-4). The small node (803-4) can receive AI/ML-mobility reporting information for supporting AI/ML-mobility parameters and/or learning model functions from the terminal (804-2). The small node (803-4) can transmit radio resource configuration information (e.g., radio resource configuration information for the terminal (804-2)) allocated by the macro node (803-1), which is a target communication node determined in the boundary area 7 (806-7, 1003), to the terminal (804-2). The terminal (804-2) can receive radio resource configuration information allocated by the macro node (803-1) from the small node (803-4). In other words, the terminal (804-1), the small node (803-4) which is a serving cell, and/or the macro cell (803-1) which is a target cell can exchange control information (e.g., AI/ML-mobility configuration information, AI/ML-mobility parameters, and/or AI/ML-mobility reporting information) in advance for supporting learning model functions.

In the case where a cell switching procedure is performed from a serving cell, a small node (803-4), to a target cell, a macro node (803-1), based on a learning model according to the above-described method, the terminal (804-2) can perform the cell switching procedure without performing the "step of transmitting a message requesting cell switching to the serving small node (803-4) by the terminal (804-2)" and/or the "step of receiving a control message instructing performance of cell switching from the serving small node (803-4) to the target macro node (803-1)." In other words, a terminal (804-2) that has entered boundary area 7 (806-7, 1003) can perform or complete a cell switching procedure (e.g., a mobility procedure) by transmitting an uplink channel to a target macro node (803-1) and/or receiving a downlink channel from the target macro node (803-1) without performing any procedure for transmitting and receiving a control message for a cell switching procedure (e.g., a mobility procedure) with a serving small node (803-4).

In order to establish uplink synchronization (e.g., establish uplink physical layer synchronization) between a terminal (804-2) that has entered boundary area 7 (806-7, 1003) and a target macro node (803-1) according to the learning-based cell switching procedure described above, the target macro node (803-1) may transmit uplink physical channel transmission timing adjustment information to the terminal (804-2). The terminal (804-2) may receive uplink physical channel transmission timing adjustment information from the target macro node (803-1). Alternatively, the serving small node (803-4) may transmit uplink physical channel transmission timing adjustment information for the target macro node (803-1) to the terminal (804-2) using the synchronization information of the communication node(s) received from the terminal. The terminal (804-2) may receive uplink physical channel transmission timing adjustment information from the serving small node (803-4).

Based on the above-described learning model-based mobility control/management method, cell switching procedures (e.g., mobility procedures) can be performed in boundary area 5 (806-5, 1004), boundary area 4 (806-4, 1005), and/or boundary area 3 (806-3, 1006).

The communication node (803-1, 803-2) and/or the terminal (804-2) can estimate (e.g., predict) the time required for the terminal (804-2) to arrive at boundary point 2 (806-2, 1007), the arrival time of the terminal (804-2) to arrive at boundary point 2 (806-2, 1007), and the distance from the location of the terminal (804-2) to boundary point 1 (806-1, 1008) by using the above-described learning model-based estimation/prediction technique. The boundary point 2 (806-2, 1007) may be a point where the terminal (804-2) leaves the ground node service area (802-2) on the movement path (803-2). The terminal (804-2) may periodically or aperiodically update, generate, and/or store AI/ML-mobility parameters based on AI/ML-mobility configuration information set for a learning model-based mobility control/management function, and transmit AI/ML-mobility report information (e.g., AI/ML-mobility report information including AI/ML-mobility parameters) to a serving communication node. The serving communication node may receive AI/ML-mobility report information from the terminal (804-2). The AI/ML-mobility parameters may include at least one of the location information of the terminal described above, wireless channel quality, an event condition set for mobility control, movement status information of the terminal, difference information (e.g., deviation information) between stored boundary point information (e.g., stored boundary area information) and measured (e.g., calculated) boundary point information (e.g., measured (e.g., calculated) boundary area information), movement time information, required time information, or movement distance information.

Considering the movement status information of the terminal (804-2), the communication nodes (803-1, 803-2) can transmit to the terminal (804-2) an estimation result (e.g., a prediction result) regarding the time required for the terminal (804-2) to arrive at boundary point 2 (806-2, 1007) on the movement path (807-2) of the terminal (804-2), the arrival time of the terminal (804-2) to boundary point 2 (806-2, 1007), and/or the distance from the location of the terminal (804-2) to boundary point 2 (806-2, 1007). The terminal (804-2) can receive the estimation result from the communication nodes (803-1, 803-2). Considering the movement status information of the terminal (804-2), the communication node (803-1, 803-2) can transmit to the terminal (804-2) an estimation result (e.g., a prediction result) regarding the time required for the terminal (804-2) to arrive at boundary point 1 (806-1, 1008) on the movement path (807-2) of the terminal (804-2), the arrival time of the terminal (804-2) to boundary point 1 (806-1, 1008), and/or the distance from the location of the terminal (804-2) to boundary point 1 (806-1, 1008). The terminal (804-2) can receive the estimation result from the communication node (803-1, 803-2). The boundary point 1 (806-1, 1008) can be a point where the air node service area (802-1) starts.

For a terminal in an RRC connection state, a communication node (803-1, 803-2) can transmit estimation result information (e.g., prediction result information) to the terminal using a dedicated control message (e.g., an RRC message, a MAC layer control message, and/or a physical layer control message). The estimation result information (e.g., prediction result information) transmitted via the dedicated control message may include "estimation result information (e.g., prediction result information) on the required time/arrival time from the current position of the terminal (or, boundary point 2 (806-2, 1007) on the movement path (803-2)) to boundary point 1 (806-1, 1008) (or, service initiation time according to the trajectory of the air node (801))" and/or "estimation result information (e.g., prediction result information) on the distance from the current position of the terminal (or, boundary point 2 (806-2, 1007) on the movement path (803-2)) to boundary point 1 (806-1, 1008) (or, service initiation time according to the trajectory of the air node (801))".

For a terminal in an RRC inactive state or an RRC idle state, the communication node (803-1, 803-2) may use system information or a terminal state transition control message (e.g., an RRC connection re-establishment message, an RRC connection release message, and/or an RRC resume message) to "estimate result information (e.g., prediction result information) on the required time/arrival time from the boundary of the ground node service area (802-2) (e.g., boundary point 2 (806-2, 1007)) to boundary point 1 (806-1, 1008) (or, a recognized service start time based on trajectory information and/or history information of the air node (801)" and/or "estimate result information (e.g., prediction result information) on the required time/arrival time from the boundary of the ground node service area (802-2) (e.g., boundary point 2 (806-2, 1007)) to boundary point 1 (806-1, 1008) (or, an air node (801))". Based on the trajectory information and/or history information of the node (801), the estimated result information (e.g., predicted result information) regarding the distance to the recognized service initiation time can be transmitted to the terminal.

When the terminal (804-2) is in an RRC connection state receiving a service from the communication node (803-1, 803-2), the terminal (804-2) and/or the communication node (803-1, 803-2) can complete the service before the terminal (804-2) arrives at the boundary point 2 (806-2) on the moving path (803-2). The terminal (804-2) and/or the communication node (803-1, 803-2) can prepare for the terminal (804-2) to enter the air node service area (802-1) and resume the service. For the above operation, the operation state of the terminal can transition to the RRC idle state or the RRC inactive state. In other words, during the period from the end time of the previous service to the start time of the next service, the operation state of the terminal can be the RRC idle state or the RRC inactive state. The terminal may be in OoS state during the period from the end time of the previous service to the start time of the next service.

The terminal (804-2) may arrive at the boundary point 2 (806-2) at the predicted time (1007) signaled by the communication nodes (803-1, 803-2) in the ground node service area (802-2). In this case, the terminal (804-2) may determine whether its location is located within the ground node service area (802-2). For example, the terminal (804-2) may measure the wireless channel quality for the communication node (803-1), which is a serving cell (or camping cell). If the measured wireless channel quality is less than the criterion condition for determining whether it is located within the ground node service area (802-2), the terminal (804-2) may determine that it has left the ground node service area (802-2). In other words, the terminal (804-2) may determine that it is in an OoS state for the ground node service area (802-2). The reference condition (e.g., the reference condition for determining whether the terminal (804-2) is in the OoS state) may be a cell/node detection criterion (1001) for a cell search procedure, a cell camping condition (1011), and/or a reference value for determining the OoS state. The cell camping condition (1011) may be a condition for a cell (re)selection procedure of a terminal in an RRC inactive state or an RRC idle state. The terminal (804-2) may arrive at the boundary point 1 (806-1) late before or after the predicted time (1007) signaled from the communication node. Regardless of the time of arrival at the boundary point 1 (806-1), the terminal (804-2) may determine whether the terminal (804-2) is in the OoS state for the air node service area (802-1) according to the above-described method.

A terminal (804-2) in OoS state can periodically or aperiodically measure (e.g., calculate) a moving time, distance, moving direction, etc. from boundary point 2 (806-2, 1007) to boundary point 1 (806-1, 1008) while moving, and add, generate, and/or update AI/ML-mobility parameters based on the measurement information. Based on the AI/ML-mobility configuration information for a terminal in an RRC inactive state or an RRC idle state, the terminal (804-2) can reduce unnecessary power consumption of the terminal by deactivating a cell search function while moving from a boundary of a ground node service area (802-2) (e.g., boundary point 2 (806-2)). In other words, during the period from the end time of a previous service to the start time of a next service, the terminal (804-2) may not perform a cell search procedure. The terminal (804-2) can perform a cell search procedure by activating the cell search function based on the turning/changing of its own moving direction and/or the updated AI/ML-mobility parameters. In other words, when the terminal (804-2) enters a new service area, the terminal (804-2) can perform a cell search procedure.

The terminal (804-2) can arrive at the boundary point 1 (806-1, 1008) of the air node service area (802-1) via the boundary point 2 (806-2, 1007) on the movement path (807-2). In this case, the terminal (804-2) can receive service from the air node (801). The terminal (804-2) can camp in the air node service area (802-1). In other words, if it is determined that the terminal (804-2) has entered the air node service area (802-1), the terminal (804-2) can camp in the air node service area (802-1).

The terminal (804-2) can recognize that the terminal (804-2) is close to the boundary point 1 (806-1, 1008) based on the learning model function based on the AI/ML-mobility setting information acquired from the communication node of the ground node service area (802-2). In this case, the terminal (804-2) can activate the cell search function.

The terminal (804-2) may arrive at boundary point 1 (806-1) at T1 (1008-1) earlier than the predicted time (1008) indicated from the communication node of the ground node service area (802-2). Alternatively, the terminal (804-2) may arrive at boundary point 1 (806-1) at T2 (1008-2) later than the predicted time (1008) indicated from the communication node of the ground node service area (802-2). Regardless of the time of arrival at boundary point 1 (806-1), the terminal (804-2) may determine whether the terminal (804-2) belongs to the air node service area (802-1) according to the above-described method. Regardless of the time of arrival at boundary point 1 (806-1), the terminal (804-2) may perform the cell search procedure according to the above-described method. Based on the result of the cell search procedure, when the wireless channel quality of the air node (801) is equal to or higher than the cell camping condition (1011) at a time point (1008-2), the terminal (804-2) can camp on the air node (801). The terminal (804-2) in the RRC inactive state or the RRC idle state can receive AI/ML-mobility configuration information from the air node (801) on which it has camped.

In order to resume a suspended service or receive a new service, the terminal (804-2) can transition to an RRC connected state by performing an access procedure. The terminal (804-2) in the RRC connected state can receive AI/ML-mobility configuration information from the serving cell, the air node (801), using a dedicated control message, and can receive a requested service from the serving cell, the air node (801). The dedicated control message transmitted by the air node (801) can include AI/ML-mobility configuration information.

If the air node service area (802-1) and the ground node service area (802-2) do not overlap, the terminal (804-6) may be located in an area where no service is provided. The terminal (804-1) moving along the movement path (807-1) may be located in an area where no service is provided. The terminal (804-2) moving along the movement path (807-2) may be located in an area where no service is provided. The terminals (804-1, 804-2, 804-6) located in the area where no service is provided may perform a cell search procedure according to conditions set for the terminals (804-1, 804-2, 804-6) in order to find a camping cell or a serving cell. In this case, the battery power consumption of the terminals (804-1, 804-2, 804-6) may continuously increase. To solve the above problem, unnecessary cell search functions of the terminal in areas (e.g., OoS) other than the air node service area (802-1) and the ground node service area (802-2) can be disabled. Accordingly, an increase in power consumption of the terminal can be alleviated.

For example, according to the method described above, the communication nodes (801, 803-1, 803-2) and/or the terminals (804-1, 804-2, 804-6) can estimate (e.g., predict) whether the terminals (804-1, 804-2, 804-6) enter a boundary point (e.g., boundary point 1 (806-1), boundary point 2 (806-2)) of the service area of the communication nodes based on channel quality information, time information, and/or distance information. The communication nodes (801, 803-1, 803-2) can transmit information about the boundary points (806-1, 806-2) of the service areas of the communication nodes (801, 803-1, 803-2) to the terminals (804-1, 804-2, 804-6). The terminals (804-1, 804-2, 804-6) can receive information about boundary points (806-1, 806-2) of service areas from the communication nodes (801, 803-1, 803-2). The information about the boundary points (806-1, 806-2) may be geographic location information. Alternatively, the information about the boundary points (806-1, 806-2) may mean a current location of the terminal based on movement status information of the terminal, a time required/arrival time from a boundary of a service area (e.g., a boundary point) to a boundary of another service area (e.g., a boundary point), and/or an estimation result (e.g., a prediction result) for a distance from a boundary of a service area (e.g., a boundary point) to a boundary of another service area (e.g., a boundary point).

According to the above-described method, based on information about a boundary (e.g., a boundary point) of an air node service area (802-1) or a ground node service area (802-2) received from a communication node and/or information estimated by the terminal (e.g., a required time, an arrival time, and/or a distance), the terminal may not perform an unnecessary cell search procedure. When the movement status information of the terminal has changed, the terminal may perform a cell search procedure according to an existing setting condition (e.g., a basic setting condition). The change in the movement status information may mean that at least one of a movement speed, a movement trajectory, a movement path, a movement direction, a starting point, a waypoint, or a destination included in the movement status information has changed.

Based on the above-described method and learning model function support, the terminal can recognize that it does not belong to either the air node service area or the ground node service area. In this case, the terminal can disable the cell search function so as not to perform an unnecessary cell search function. The terminal can exchange a control message with the communication node, and determine whether the service area condition is satisfied based on the stored information, the location information, and/or the movement status information. If the service area condition is satisfied, the terminal can perform a cell search procedure for service initiation or camping by activating the cell search function.

Based on the learning model described above, communication nodes (801, 803-1, 803-2, 803-3, 803-4) and/or terminals (804-1, 804-2, 804-3, 804-4, 804-5, 804-6) can improve the prediction accuracy for the time when the terminal arrives at or approaches a boundary point (806-1, 806-2) and/or a boundary area (806-3, 806-4, 806-5, 806-6, 806-7) on the moving path (806-1, 806-2). For example, according to the above-described method, the terminals (804-1, 804-2, 804-3, 804-4, 804-5, 804-6) can transmit quality information of a wireless channel, movement status information of the terminal, location information (e.g., geographic location information, location information measured based on a reference signal, location information measured based on a sensor), and/or arrival time information for a specific location to the communication nodes (801, 803-1, 803-2, 803-3, 803-4). The communication nodes (801, 803-1, 803-2, 803-3, 803-4) can receive the above-described information from the terminals (804-1, 804-2, 804-3, 804-4, 804-5, 804-6).

The movement status information of the terminal may include at least one of a movement speed, a movement trajectory, a movement path, a movement direction, a starting point, a waypoint, or a destination. The movement direction may be information about the direction in which the terminal moves. The movement direction may be expressed in the form of an east/west/south/north direction (e.g., southeast direction, north/northwest direction), a direction based on an angle (e.g., 360 degrees) (e.g., 10 degree direction, 90 degree direction), and/or a clockwise direction (e.g., 1 o'clock direction, 6 o'clock direction). The east/west/south/north directions may be set (e.g., indicated) based on the magnetic north according to the Earth's magnetic field or the north direction indicated on a map. The angle-based direction and/or the clockwise direction may be set based on the current moving direction of the terminal. Alternatively, the angle-based direction and/or the clockwise direction may be set based on a distance, location, etc. between wireless network(s), communication node(s), and/or terminal(s). The information about the origin, the waypoint, and/or the destination may be geographic location information. Alternatively, the information about the origin, the waypoint, and/or the destination may be expressed in the form of "distance information from the location of the communication node and/or terminal to the point" and/or "time information from the location of the communication node and/or terminal to the point." For example, the distance information may be expressed in the form of "the location of the communication node and/or terminal" or "the predicted distance from the origin of the terminal to the waypoint or destination." The time information may be expressed in the form of "the location of the communication node and/or terminal," "the predicted time taken by the terminal to move from the origin to the waypoint or destination considering the movement status information," and/or "the time (e.g., the predicted time) at which the terminal arrives at the waypoint or destination considering the movement status information."

Communication nodes (801, 803-1, 803-2, 803-3, 803-4) can predict the time at which a terminal arrives at or approaches a boundary point (806-1, 806-2) and/or a boundary area (806-3, 806-4, 806-5, 806-6) on a movement path by utilizing information received from terminals (804-1, 804-2, 804-3, 804-4, 804-5, 804-6), OAM (Operations, Administration, and Maintenance) information received from a wireless network, and storage information of the communication nodes as input parameters or parameters of a learning model. The communication node (801, 803-1, 803-2, 803-3, 803-4) may perform control or instruction for connection control and mobility function support (e.g., beam switching, multi-beam setup, switching of communication nodes, dual connectivity, redundant transmission setup, and/or multi-RAT connection) for the corresponding terminal based on the predicted time.

The terminals (804-1, 804-2, 804-3, 804-4, 804-5, 804-6) can receive information (e.g., boundary information) about boundary points (806-1, 806-2) and/or boundary areas (806-3, 806-4, 806-5, 806-6, 806-7) on the movement path of the terminal from the communication nodes (801, 803-1, 803-2, 803-3, 803-4). The boundary information may include "geopolitical location information for the boundary point (806-1, 806-2) and/or the boundary area (806-3, 806-4, 806-5, 806-6, 806-7)", "prediction information for the time at which the terminal arrives at the boundary point (806-1, 806-2) and/or the boundary area (806-3, 806-4, 806-5, 806-6, 806-7)", and/or "reference information (e.g., a reference value) of wireless channel quality for recognizing the boundary point (806-1, 806-2) and/or the boundary area (806-3, 806-4, 806-5, 806-6, 806-7)".

In a cell switching procedure for a terminal in an RRC connection state to change a serving cell (e.g., a serving communication node) to a target cell (e.g., a target communication node) or a cell (re)selection procedure performed by a terminal in a non-RRC connection state, the terminal may generate the AI/ML-mobility configuration information described above. The terminal may transmit (e.g., report) the AI/ML-mobility configuration information to a communication node, if necessary. The communication node may receive the AI/ML-mobility configuration information from the terminal. The communication node may transmit priority information for selecting a target cell in the cell switching procedure or a camping cell in the cell (re)selection procedure to the terminal. The terminal may receive the priority information from the communication node. The priority information may include "information on which node among a ground node and an air node is to be selected with priority" and/or "information on which frequency (e.g., a frequency band) of a ground node and a frequency (e.g., a frequency band) of an air node is to be selected with priority."

AI/ML-mobility parameters transmitted by the terminal to the communication node, AI/ML-mobility reporting information for supporting learning model functions, AI/ML-mobility configuration information, and/or cell switching (or beam switching) request messages may include one or more of the information described in Table 1 below.

The movement path information of the terminal may include the current location of the terminal, the waypoint of the terminal, the destination of the terminal, and/or the predicted next location information of the terminal on the movement path of the terminal. The predicted next location information may mean the predicted location information after a preset time has elapsed and/or after the terminal has moved a preset distance. For example, the predicted next location information may be the location of the terminal predicted 10 seconds (sec) from the current location of the terminal. The predicted next location information may be the location of the terminal predicted after the terminal has moved 100 meters (meters) from the current location. The preset time and/or the preset distance may be set by the communication node. Information about the preset time and/or the preset distance may be included in the movement path information of the terminal together with the next location information of the terminal. The location information of the terminal may be a geographic location based on a positioning signal, a relative location on a movement path, a location indicated based on a moving direction of the terminal on a movement path, a location indicated based on wireless channel quality, and/or a location indicated based on a measurement result of a built-in sensor.

The cell switching timing information may be information on the time at which the terminal accesses the target cell and/or information on the time at which the terminal leaves the serving cell. The time information at which the terminal accesses the target cell may mean information on "the timing and/or time interval at which the terminal transmits an uplink channel to the target cell" and/or "the timing and/or time interval at which the terminal receives a downlink channel from the target cell." The time information at which the terminal lives in the serving cell may mean information on "the timing and/or time interval at which the terminal stops transmitting an uplink channel to the serving cell" and/or "the timing and/or time interval at which the terminal stops receiving a downlink channel from the serving cell."

The terminal can measure (e.g., calculate) AI/ML-mobility information periodically or aperiodically, and add, generate, and/or update AI/ML-mobility parameters based on the AI/ML-mobility information. The terminal can transmit (e.g., report) a control message (e.g., a parameter, an AI/ML-mobility parameter) to a serving cell or a target cell in the form of an RRC control message, a MAC control message, and/or a field parameter of a physical layer control channel. Here, the RRC control message can be a cell switching request message, a periodic measurement report message, an aperiodic measurement report message, an RRC connection control message, a control message for RRC resumption, an RLF (radio link failure) report message, a control message for beam recovery, and/or a control message for routing area update. A MAC control message may mean a MAC control PDU (protocol data unit) for a MAC-based cell switching request and/or a MAC control PDU for reporting AI/ML-mobility parameters (e.g., AI/ML-mobility information, AI/ML-mobility reporting information).

The communication node may receive AI/ML-mobility parameters, AI/ML-mobility reporting information for supporting learning model functions, and/or a cell switching (or beam switching) request message from the terminal. In this case, the communication node may transmit a control message to the terminal that instructs cell switching for a cell preferred by the terminal (e.g., a cell determined by the terminal). The terminal may receive the control message that instructs cell switching from the communication node. The control message that instructs cell switching may include one or more pieces of information described in Table 2 below.

The time information that the terminal lives in the serving cell may mean the above-described cell switching timing information. The location information of the terminal for performing cell switching may mean the location information of the terminal for performing cell switching to the target cell.

A terminal can receive cell switching timing information from a communication node. The terminal can stop a transmission operation of an uplink channel to a serving cell and/or a reception operation of a downlink channel from the serving cell based on serving cell living time information indicated by the communication node. If target cell access time information indicated by the communication node and/or location information of the terminal for performing cell switching satisfies preset condition(s), the terminal can perform a cell switching procedure (e.g., a cell switching operation) to the target cell. In other words, the terminal can perform a transmission operation of an uplink channel to the target cell and/or a reception operation of a downlink channel from the target cell.

When a communication node and/or a terminal supports a mobility function based on AI/ML-mobility information (e.g., AI/ML-mobility configuration information) and/or a learning model, the terminal can determine a target cell based on the AI/ML-mobility information and/or the learning model. In other words, the terminal can determine a target cell and/or a target beam based on consultation with the communication node, and can request switching for the determined target cell and/or the determined target beam. Alternatively, the terminal can determine a target cell and/or a target beam based on AI/ML-mobility information (e.g., AI/ML-mobility configuration information) and/or a learning model configured by a serving cell, and can request switching for the determined target cell and/or the determined target beam. The serving cell can transmit cell switching information (e.g., cell switching instruction information) for the target cell determined by the terminal to the terminal, and can initiate a cell switching procedure to the target cell. The terminal can receive cell switching indication information for a target cell selected by the terminal from the serving cell (e.g., configuration information for a target cell allocated (or scheduled) to the terminal), and perform a cell switching procedure to the target cell based on the cell switching indication information.

A terminal can determine a target cell and perform a cell switching procedure (e.g., a cell switching operation) based on a forward handover scheme. In the cell switching procedure based on the forward handover scheme (hereinafter, referred to as a "UE-centric cell switching procedure"), the terminal may not transmit a control message requesting cell switching to a serving cell, and the terminal may directly transmit a control message requesting cell switching to the target cell in order to initiate a service from the target cell. Alternatively, the terminal may perform an access procedure (e.g., a random access procedure, an uplink physical layer synchronization acquisition procedure, and/or a radio resource allocation request procedure) with the target cell in order to initiate a service from the target cell. The radio resource allocation request procedure may mean a procedure in which the terminal transmits a control message and/or parameters requesting allocation of radio resources (e.g., scheduling) of downlink and/or uplink to the target cell.

In a UE-centric cell switching procedure, which is a cell switching procedure for a target cell without going through a serving cell (e.g., without controlling the serving cell), a terminal may transmit connection setup information established for a service provided in a previous serving cell to the target cell. A communication node may receive a control message requesting a UE-centric cell switching procedure from a terminal. In this case, before or after initiating a service for a terminal that has requested a UE-centric cell switching procedure, the communication node may use the connection setup information established for a service provided in a previous serving cell received from the terminal to notify an entity of a core network that the UE-centric cell switching procedure for the terminal is performed. The communication node may update control information for supporting a mobility function for the terminal. A function for the UE-centric cell switching procedure may support a D(data)/C(control) separate cell switching function in connection setup between a communication node and a terminal. The D/C separate cell switching function may mean a switching function that separates data (e.g., user plane or traffic plane) and control (e.g., control plane) for a communication node to provide a service to a terminal.

When a serving cell for a terminal is changed based on a UE-centric cell switching procedure, only connection setup information and/or radio resource allocation information (e.g., radio resource scheduling information) for a user plane or a traffic plane for the terminal may be changed for the target cell. The configuration of a control plane for an existing serving cell or an anchor node may be maintained. A cell switching function for connection control may be supported without changing the configuration of a control plane for an existing serving cell or an anchor node. When a D/C separate cell switching function is supported based on the UE-centric cell switching function, a communication node may provide service continuity for the terminal only by adding/changing the same MAC entity and/or a new MAC entity without changing an RRC performing node for the terminal. In this case, a control message for a cell switching operation between the terminal and/or the communication node may be a MAC layer control message. The MAC layer control message may mean a MAC control PDU or a MAC control PDU for cell switching (or beam switching) based on LTM (L1/L2 triggered mobility).

For LTM-based cell switching (or beam switching), a control message for a cell switching operation (or beam switching operation) between a terminal and/or a communication node may be transmitted and received using a physical layer control signal (e.g., a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH)), a separately defined control signal, and/or a separately defined reference signal. Each of the separately defined control signal and the separately defined reference signal may be transmitted through a physical layer channel/signal.

When performing a cell switching procedure (e.g., cell switching operation) based on AI/ML-mobility information (e.g., AI/ML-mobility configuration information) and/or a learning model based on the above-described method, the communication node and/or the terminal may estimate (e.g., predict) whether the terminal enters the boundary point and/or boundary area in the movement path, a target cell, a camping cell, cell switching timing information, etc. by using the location information of the terminal included in the above-described AI/ML-mobility information, wireless channel quality, movement path information, movement time information, movement distance information, the time (e.g., predicted time) at which the terminal arrives at a specific point (e.g., boundary point, boundary area), the distance from the position of the terminal to the specific point, and/or difference information (e.g., error, deviation) for movement status information.

The communication node and/or terminal estimating (e.g., predicting) the above-described information may mean that the parameter values for the cell-level wireless channel quality, the beam-level wireless channel quality, the location of the terminal (e.g., the geographic location, the relative location along the movement path, the location indicated based on the movement direction, the location indicated based on the wireless channel quality, and/or the location indicated based on the measurement results of the built-in sensor), the movement status of the terminal, the travel time for the movement distance of the terminal, the time for the terminal to arrive at a preset point, the distance from the location of the terminal to the preset point, etc. are inferred (e.g., predicted in advance) using the AI/ML-mobility information and/or the learning model. In other words, the communication node and/or the terminal can predict, within a certain range, the parameter values that are the results of the execution of the AI/ML-based learning model based on the reported data, the transmitted data, the collected data, and/or the AI/ML-mobility information.

The communication node and/or the terminal can determine a camping cell for cell (re)selection of the terminal that is not in an RRC connection state by using measurement information, report information, and/or a result of performing an AI/ML-based learning model (e.g., predicted information). The terminal and/or the communication node in the RRC connection state can determine a target cell and/or cell switching timing information for cell switching, and exchange the determined information. The terminal can receive cell switching timing information (e.g., target cell access time and/or serving cell living time information) from the communication node, and perform a cell switching operation to a target cell indicated by the communication node or a target cell determined by itself (e.g., the terminal) based on the cell switching timing information.

When the mobility control/management function operates based on AI/ML-mobility information and/or learning model, the communication node and/or terminal can avoid unnecessary cell switching operations and/or frequent cell switching operations. The communication node and/or terminal can request to stop the cell switching operation in the boundary area and/or instruct to stop (or hold) the cell switching operation. Alternatively, the communication node and/or terminal can avoid unnecessary cell switching operations by performing the cell switching operation according to the cell switching timing information. For example, based on stored data or the inference result of the learning model (e.g., the movement status of the terminal, the location information of the terminal, the quality status of the wireless channel, the load status of the network, and/or the OAM information of the network), the communication node and/or terminal can determine an optimal target cell, the location of the terminal for cell switching, and/or cell switching timing information. The communication node can transmit a control message instructing cell switching to the target cell. A control message that instructs cell switching transmitted by a communication node may include information on a target cell, location information of a terminal for cell switching, and/or cell switching timing information. The terminal may receive the above-described information (e.g., the above-described parameter) from the communication node. If the location of the terminal on the moving path matches the location indicated by the communication node and/or if a condition according to the cell switching timing information in the time domain is satisfied, the terminal may perform a cell switching operation to the target cell.

Figure 11 is a flowchart illustrating a mobility control procedure.

Referring to FIG. 11, a random access procedure or a resume procedure between a terminal and a base station may be performed in S1101. In other words, an RRC connection establishment procedure or an RRC (re)configuration procedure between a terminal and a base station may be performed in S1101. The base station may include a CU and a DU, the CU may include cell 1 and cell 2, cell 1 may include TRP1 and TRP2, and cell 2 may include TRP3. When S1101 is completed, the terminal may be connected to cell 1 of the base station. In S1102, the terminal may perform downlink communication (e.g., PDCCH reception and/or PDSCH reception) with cell 1 of the base station. In S1103, the terminal may perform uplink communication (e.g., PUCCH transmission and/or PUSCH transmission) with cell 1 of the base station. Cell 1 can perform downlink communication and/or uplink communication with a terminal through one or more TRPs (e.g., TRP1 and/or TRP2).

In S1104, the cell 1 of the base station can transmit a beam measurement report instruction (e.g., a TRP measurement report instruction) to the terminal, and the terminal can receive the beam measurement report instruction from the cell 1 of the base station. In S1105-1, the terminal can report the L1/L2 measurement result to the cell 1 based on the beam measurement report instruction. Alternatively, S1104 may be omitted. In this case, in S1105-1, the terminal can report the L1/L2 measurement result to the cell 1 without the beam measurement report instruction. In other words, when a specific event occurs, the terminal can report the L1/L2 measurement result to the cell 1 without the beam measurement report instruction. In S1105-1, the cell 1 can receive the L1/L2 measurement result from the terminal. In S1105-2, the cell 1 can report the L3 measurement result to the CU, and the CU can receive the L3 measurement result from the cell 1. The L3 measurement result can be generated based on the L1/L2 measurement result.

In S1106, the terminal may transmit a MAC-based cell switching request to cell2, and cell2 may receive the MAC-based cell switching request from the terminal. If it is determined that a cell switching operation is necessary, the terminal may transmit a MAC-based cell switching request to cell2. In other words, the terminal may determine whether a cell switching operation is necessary based on AI/ML-mobility configuration information and/or measurement information (e.g., radio quality information). The base station (e.g., DU) may determine whether to perform the cell switching operation based on the MAC-based cell switching request of the terminal. For example, the base station (e.g., DU) may determine whether a cell switching operation is necessary based on AI/ML-mobility configuration information and/or radio quality information. If it is determined that the cell switching operation is performed (e.g., if it is determined that a cell switching operation is necessary), the DU may transmit cell change information (e.g., TRP change information, beam change information) to the CU (S1108). In S1108, the CU can receive cell change information (e.g., TRP change information, beam change information) from the DU.

If it is determined that a cell switching operation is performed (e.g., if it is determined that a cell switching operation is necessary), the DU may transmit a MAC-based cell switching request response to the terminal (S1109). The MAC-based cell switching request response may be transmitted from cell 1 (e.g., TRP1 and/or TRP2) and/or cell 2 (e.g., TRP3). In S1109, the terminal may receive the MAC-based cell switching request response from cell 1 and/or cell 2. If the MAC-based cell switching request response is received, the terminal may perform a cell switching operation to cell 2. If the cell switching operation is completed, downlink communication (e.g., PDCCH reception and/or PDSCH reception) and/or uplink communication (e.g., PUCCH transmission and/or PUSCH transmission) between the terminal and cell 2 may be performed in S1110.

In the present disclosure, the wireless channel quality may be a Channel Status Indicator (CSI), a Received Signal Strength Indicator (RSSI), a Reference Signal Received Power (RSRP), a Reference Signal Received Quality (RSRQ), or a Signal to Interference and Noise Ratio (SINR). In other words, the wireless channel quality may mean a signal quality in a wireless channel section. In the present disclosure, the measurement result may be defined based on the wireless channel quality.

In the present disclosure, prediction may mean predicting (e.g., inferring) the quality of a wireless channel per cell, the quality of a wireless channel per beam, the geographic location of a terminal, the movement status of the terminal, the travel time for the movement distance of the terminal, the arrival time of the terminal at a preset point, etc., using AI/ML-mobility information and/or a learning model. In the present disclosure, a time point may mean time.

In the present disclosure, AI/ML-mobility information, AI/ML-mobility report information, AI/ML-mobility configuration information, and AI/ML-mobility parameters may be interpreted as the same information (e.g., the same parameter) depending on the context. Alternatively, AI/ML-mobility information, AI/ML-mobility report information, AI/ML-mobility configuration information, and AI/ML-mobility parameters in the present disclosure may be interpreted as distinct information (e.g., distinct parameters) depending on the context.

In the present disclosure, start, stop, reset, restart, and/or expire of a timer may mean or include a counter operation for the timer. In the present disclosure, location information may mean geographic location information or geographical location information of a terminal measured using a satellite navigation device (e.g., GPS, GNSS (Global Navigation Satellite System)), a geographic information system (GIS), a positioning technique, and/or sensor information. In other words, the location information of the terminal may mean geographic location information based on a positioning signal, relative location information in a moving path, location information indicated based on a moving direction of the terminal in a moving path, location information indicated based on wireless channel quality, and/or location information indicated based on a measurement result of a built-in sensor.

In the present disclosure, a communication node may mean a communication node (e.g., a base station, an eNB, a gNB, a cell, an NTN node, an IAB node, a wireless access point (e.g., a TRP, an RRH, a relay, or a repeater, etc.)) to which functions of functional separation, carrier aggregation, dual connectivity, multi-RAT connectivity, and/or redundant transmission are applied. A terminal may be referred to as a UE, an access terminal, a mobile terminal, a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, an IoT (Internet of Thing) device, a mounted module, a mounted device, a mounted terminal, an on board device, an on board terminal, a wearable device, and/or an HMD.

The operation of the method according to an embodiment of the present disclosure can be implemented as a computer-readable program or code on a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording devices that store information that can be read by a computer system. In addition, the computer-readable recording medium can be distributed over network-connected computer systems so that the computer-readable program or code can be stored and executed in a distributed manner.

Additionally, the computer-readable recording medium may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. The program instructions may include not only machine language codes generated by a compiler, but also high-level language codes that can be executed by the computer using an interpreter, etc.

While some aspects of the present disclosure have been described in the context of an apparatus, that may also represent a description of a corresponding method, wherein a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method may also be described as a feature of a corresponding block or item or a corresponding device. Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, a programmable computer or an electronic circuit. In some embodiments, at least one or more of the most significant method steps may be performed by such a device.

In embodiments, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functions of the methods described herein. In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by some hardware device.

Although the present disclosure has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present disclosure without departing from the spirit and scope of the present disclosure as set forth in the claims below.

Claims (20)

As a method of UE (user equipment), A step of receiving first AI (Artificial Intelligence)/ML (Machine Learning)-mobility setting information for mobility control from a first communication node; A step of identifying a first predicted time at which the UE leaves the first service area of the first communication node based on the first AI/ML-mobility setting information; A step of determining whether the UE leaves the first service area of the first communication node at the first predicted time; A step of confirming a second predicted time at which the UE enters a second service area of a second communication node based on the first AI/ML-mobility setting information; and A step of performing a mobility procedure with the second communication node based on the second predicted time, UE's method. In claim 1, The first AI/ML-mobility setting information includes at least one of information about a time when the UE leaves the first service area of the first communication node, information about a time when the UE enters the second service area of the second communication node, an event condition set for the mobility control, a geographical location set for the mobility control, or location information of an adjacent communication node. UE's method. In claim 1, When the UE is in an RRC (radio resource control) connection state to the first communication node, the first AI/ML-mobility configuration information is received through a dedicated control message of the first communication node. UE's method. In claim 1, When the UE is in an RRC inactive state or an RRC idle state with respect to the first communication node, the first AI/ML-mobility configuration information is received through the system information of the first communication node or the UE state transition control message. UE's method. In claim 1, During the period from the first prediction time to the second prediction time, the cell search procedure of the UE is deactivated. UE's method. In claim 1, During the period from the first prediction time to the second prediction time, the operation state of the UE is an RRC inactive state or an RRC idle state. UE's method. In claim 1, When the UE enters the second service area, the mobility procedure between the UE and the second communication node is performed without exchanging a control message for supporting the mobility procedure between the UE and the first communication node. UE's method. In claim 1, The mobility procedure between the UE and the second communication node is performed before or at the second predicted time. UE's method. In claim 1, Further comprising a step of receiving wireless resource setting information allocated by the second communication node from the first communication node, The above wireless resource setting information is used for transmission and reception of at least one of the downlink scheduling information or timing information of the second communication node. UE's method. In claim 1, If the mobility procedure between the UE and the second communication node is completed, further comprising the step of receiving second AI/ML-mobility setting information for the mobility control from the second communication node. UE's method. In claim 10, A step of updating AI/ML-mobility parameters based on the second AI/ML-mobility setting information; and Further comprising the step of transmitting AI/ML-mobility reporting information including updated AI/ML-mobility parameters to the second communication node. UE's method. In claim 1, The above mobility procedure is a cell switching procedure, a beam switching procedure, an access procedure, a cell selection procedure, a cell reselection procedure, or a handover procedure, and each of the first communication node and the second communication node is a base station, a cell, or a transmission and reception point (TRP). UE's method. As a UE (user equipment), Contains at least one processor, At least one of the above processes is the UE, Receive first AI (Artificial Intelligence)/ML (Machine Learning)-mobility setting information for mobility control from the first communication node; Based on the first AI/ML-mobility setting information, the UE determines a first predicted time at which the UE leaves the first service area of the first communication node; At the first predicted time, determine whether the UE leaves the first service area of the first communication node; Based on the above first AI/ML-mobility setting information, the UE determines a second predicted time at which the UE enters a second service area of a second communication node; and Causing the second communication node to perform a mobility procedure based on the second predicted time. UE. In claim 13, The first AI/ML-mobility setting information includes at least one of information about a time when the UE leaves the first service area of the first communication node, information about a time when the UE enters the second service area of the second communication node, an event condition set for the mobility control, a geographical location set for the mobility control, or location information of an adjacent communication node. UE. In claim 13, When the UE is in an RRC (radio resource control) connection state to the first communication node, the first AI/ML-mobility configuration information is received through a dedicated control message of the first communication node. UE. In claim 13, When the UE is in an RRC inactive state or an RRC idle state with respect to the first communication node, the first AI/ML-mobility configuration information is received through the system information of the first communication node or the UE state transition control message. UE. In claim 13, During the period from the first prediction time to the second prediction time, the cell search procedure of the UE is deactivated. UE. In claim 13, During the period from the first prediction time to the second prediction time, the operation state of the UE is an RRC inactive state or an RRC idle state. UE. In claim 13, When the UE enters the second service area, the mobility procedure between the UE and the second communication node is performed without exchanging a control message for supporting the mobility procedure between the UE and the first communication node. UE. In claim 13, At least one processor of the UE, Further causing the second communication node to receive wireless resource setting information allocated by the second communication node from the first communication node, The above wireless resource setting information is used for transmission and reception of at least one of the downlink scheduling information or timing information of the second communication node. UE.

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