Method and apparatus for carrying out paging procedure in next generation energy saving mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present disclosure relates to a method for carrying out a paging procedure in a next generation energy saving mobile communication system, the method comprising the steps of: receiving, from a synchronization cell, information associated with transmission of a paging message, if a terminal is in an RRC inactive state or an RRC idle state; on the basis of the information associated with transmission of the paging message, receiving the paging message including information indicating the terminal; selecting a data cell; and carrying out an RRC connection procedure with the data cell on the basis of the paging message.

Description

Method and device for performing paging procedures in next-generation energy-saving mobile communication systems

[0001] The present invention relates to the operation of a mobile communication system terminal and base station.

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

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

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

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

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

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

[0008] The purpose of the present invention is to provide a method for a terminal to establish or resume an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving.

[0009] The present invention aims to provide a method for a terminal to receive a paging message from a sync cell and establish or resume an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving.

[0010] The present invention aims to provide a method for a terminal to receive a small message indicator from a sync cell and a page message from a data cell in a next-generation mobile communication system that supports network energy saving, thereby establishing or resuming an RRC connection with a data cell.

[0011] The present invention aims to provide a method for a terminal to receive a small message indicator from a sync cell and establish or resume an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving.

[0012] The purpose of the present invention is to provide a method for exchanging signaling between a CU and a DU in a next-generation mobile communication system that supports network energy saving.

[0013] The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0014] In order to solve the above problem, a method performed by a terminal of a wireless communication system according to an embodiment of the present invention may include the steps of: receiving information related to transmission of a paging message from a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state; receiving a paging message including information indicating the terminal based on the information related to transmission of the paging message; selecting a data cell; and performing an RRC connection procedure with the data cell based on the paging message.

[0015] Additionally, according to an embodiment, the step of selecting the data cell may include the step of transmitting a wake up signal to at least one data cell if there is no suitable data cell; the step of receiving at least one of a synchronization signal or system information from the at least one data cell; and the step of selecting the data cell from among the at least one data cell based on at least one of the synchronization signal or the system information.

[0016] Additionally, depending on the embodiment, the paging message may be transmitted from either the synchronization cell or the data cell.

[0017] Additionally, according to an embodiment, the method may further include a step of transmitting a wake up signal to at least one data cell prior to reception of the paging message, based on reception of information associated with transmission of the paging message.

[0018] In addition, a method performed by a base station of a wireless communication system according to an embodiment of the present invention for solving the above-described problem may include the steps of: transmitting information related to transmission of a paging message to a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state; transmitting, to the terminal, the paging message including information indicating the terminal based on the information related to transmission of the paging message; and receiving, from the terminal, a message requesting an RRC connection to a data cell selected by the terminal based on the paging message.

[0019] Additionally, according to an embodiment, the method may further include the steps of: receiving, from the terminal, a wake up signal transmitted to at least one data cell when there is no suitable data cell; and transmitting, to the terminal, at least one of a synchronization signal or system information to the at least one data cell.

[0020] Additionally, according to an embodiment, the data cell may be selected from among the at least one data cell based on at least one of the synchronization signal or the system information.

[0021] Additionally, depending on the embodiment, the paging message may be transmitted from either the synchronization cell or the data cell.

[0022] Additionally, according to an embodiment, the method may further include a step of receiving, from the terminal, a wake up signal transmitted to at least one data cell prior to transmission of the paging message, based on transmission of information associated with transmission of the paging message.

[0023] In addition, a terminal of a wireless communication system according to an embodiment of the present invention for solving the above-described problem may include a transceiver; and a control unit for receiving, when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state, information related to transmission of a paging message from a synchronization cell through the transceiver, receiving, through the transceiver, a paging message including information indicating the terminal based on the information related to transmission of the paging message, selecting a data cell, and performing an RRC connection procedure with the data cell based on the paging message.

[0024] In addition, a base station of a wireless communication system according to an embodiment of the present invention for solving the above-described problem may include a transceiver; and a control unit for transmitting information related to transmission of a paging message to the terminal through the transceiver in a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state, transmitting the paging message including information indicating the terminal to the terminal through the transceiver based on the information related to transmission of the paging message, and receiving, from the terminal through the transceiver, a message requesting an RRC connection to a data cell selected by the terminal based on the paging message.

[0025] One embodiment of the present invention can provide a method for a terminal to establish or resume an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving.

[0026] One embodiment of the present invention can provide a method for a terminal to receive a paging message from a sync cell and establish or resume an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving.

[0027] One embodiment of the present invention can provide a method for a terminal to receive a small message indicator from a sync cell and a page message from a data cell in a next-generation mobile communication system that supports network energy saving, thereby establishing or resuming an RRC connection with a data cell.

[0028] One embodiment of the present invention can provide a method for a terminal to receive a small message indicator from a sync cell and establish or resume an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving.

[0029] One embodiment of the present invention can provide a method for exchanging signaling between a CU and a DU in a next-generation mobile communication system that supports network energy saving.

[0030] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0031] FIG. 1a is a diagram illustrating the structure of an LTE system according to an embodiment of the present invention.

[0032] FIG. 1b is a diagram illustrating a wireless protocol structure in an LTE system according to an embodiment of the present invention.

[0033] FIG. 1c is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present invention.

[0034] FIG. 1d is a diagram illustrating a wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present invention.

[0035] FIG. 1e is a diagram illustrating a next-generation mobile communication system structure that supports network energy saving according to an embodiment of the present invention.

[0036] FIG. 1f is a diagram illustrating cells that support network energy saving according to an embodiment of the present invention.

[0037] FIG. 1g is an example of a flowchart in which a terminal receives a paging message from a sync cell and establishes or resumes an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving according to an embodiment of the present invention.

[0038] FIG. 1h is another example of a flowchart in which a terminal receives a paging message from a sync cell and establishes or resumes an RRC connection with a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0039] FIG. 1i is another example of a flowchart in which a terminal receives a paging message from a sync cell and establishes or resumes an RRC connection with a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0040] FIG. 1J is a diagram illustrating cells that support network energy saving according to an embodiment of the present invention.

[0041] FIG. 1k is a flowchart illustrating a process in which a terminal receives a small message indicator from a sync cell and a page message from a data cell to establish or resume an RRC connection with a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0042] FIG. 11 is a flowchart illustrating a process in which a terminal receives a small message indicator from a sync cell and establishes or resumes an RRC connection directly to a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0043] FIG. 1m is a flowchart showing a change in a power state of a data cell in a next-generation mobile communication system that supports network energy saving according to an embodiment of the present invention.

[0044] FIG. 1n is a flowchart illustrating a signaling exchange procedure between a CU and a DU in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0045] Figure 1o is a block diagram showing the internal structure of a terminal according to one embodiment of the present invention.

[0046] FIG. 1p is a block diagram showing the configuration of an NR base station according to an embodiment of the present invention.

[0047] The operating principles of the present invention will be described in detail below with reference to the attached drawings. In the following description of the present invention, detailed descriptions of known functions or components will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Furthermore, the terms described below are defined based on their functions in the present invention and may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0048] In the following description of the present invention, detailed descriptions of known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present invention. Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

[0049] The operating principles of the present invention are described in detail with reference to the attached diagram. The terms described below are defined based on their functions within the present invention. These terms may vary depending on the intent or custom of the user or operator, and therefore their definitions should be determined based on the overall content of this specification.

[0050] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size.

[0051] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the disclosure.

[0052] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable storage medium that can direct a computer or other programmable data processing equipment to implement a function in a specific manner, so that the instructions stored in the computer-available or computer-readable storage medium can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0053] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0054] Here, the term '~ unit' used in this embodiment means a software or hardware component such as an FPGA or ASIC, and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to regenerate one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card.

[0055] Certain terms used in the following description are provided to aid in understanding the present disclosure, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present disclosure.

[0056] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and terms referring to various identification information are provided for convenience of explanation. Therefore, the present invention is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0057] For convenience of explanation, the present invention uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP) LTE standard. However, the present invention is not limited to these terms and names and can be equally applied to systems conforming to other standards. In the present invention, the term "eNB" may be used interchangeably with "gNB" for convenience of explanation. In other words, a base station described as an eNB may also represent a gNB.

[0058] FIG. 1a is a diagram illustrating the structure of an LTE system according to an embodiment of the present invention.

[0059] Referring to FIG. 1a, as illustrated, a wireless access network of an LTE system may be composed of next-generation base stations (evolved node Bs, hereinafter referred to as ENBs, eNBs, Node Bs or base stations) (1a-05, 1a-10, 1a-15, 1a-20), MMEs (1a-25, mobility management entity) and S-GWs (1a-30, serving-gateway). User equipment (hereinafter referred to as UEs, terminals or terminals) (1a-35) may access an external network through ENBs (1a-05 to 1a-20) and S-GWs (1a-30).

[0060] In Fig. 1a, ENBs (1a-05 to 1a-20) correspond to existing Node Bs of the UMTS system. ENBs (1a-05 to 1a-20) are connected to UEs (1a-35) via a wireless channel and perform a more complex role than existing Node Bs. In the LTE system, all user traffic, including real-time services such as VoIP (Voice over IP) via the Internet Protocol, is serviced through a shared channel. Therefore, a device that collects status information such as buffer status, available transmission power status, and channel status of UEs (1a-35) and performs scheduling is required, and this is handled by ENBs (1a-05 to 1a-20). One ENB (1a-05 to 1a-20) typically controls multiple cells. For example, in order to implement a transmission speed of 100 Mbps, the LTE system uses, for example, orthogonal frequency division multiplexing (OFDM) as a wireless access technology in a 20 MHz bandwidth. In addition, the LTE system applies an adaptive modulation & coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel condition of the terminal (1a-35). The S-GW (1a-30) is a device that provides a data bearer and can create or remove a data bearer according to the control of the MME (1a-25). The MME (1a-25) is a device that is in charge of various control functions as well as mobility management functions for the terminal (1a-35) and can be connected to multiple base stations (1a-05 to 1a-20).

[0061] FIG. 1b is a diagram illustrating a wireless protocol structure in an LTE system according to an embodiment of the present invention.

[0062] Referring to FIG. 1b, the wireless protocol of the LTE system may be composed of PDCP (packet data convergence protocol 1b-05, 1b-40), RLC (radio link control 1b-10, 1b-35), MAC (medium access control 1b-15, 1b-30) in the terminal (UE) and the ENB, respectively.

[0063] PDCP (packet data convergence protocol) (1b-05, 1b-40) can handle operations such as IP header compression / decompression. The main functions of PDCP (1b-05, 1b-40) can be summarized as follows.

[0064] - Header compression and decompression (ROHC only)

[0065] - User data transfer function

[0066] - In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM

[0067] - Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0068] - Duplicate detection function (Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM)

[0069] - Retransmission function (Retransmission of PDCP SDUs at handover and, for split bearers in DC, of ​​PDCP PDUs at PDCP data-recovery procedure, for RLC AM)

[0070] - Encryption and decryption functions (Ciphering and deciphering)

[0071] - Timer-based SDU discard in uplink.

[0072] Radio link control (RLC) (1b-10, 1b-35) can perform ARQ operations, etc. by reconfiguring PDCP PDUs (packet data units) to an appropriate size. The main functions of RLC (1b-10, 1b-35) can be summarized as follows.

[0073] - Data transfer function (Transfer of upper layer PDUs)

[0074] - ARQ function (Error Correction through ARQ (only for AM data transfer))

[0075] - Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

[0076] - Re-segmentation of RLC data PDUs (only for AM data transfer)

[0077] - Reordering of RLC data PDUs (only for UM and AM data transfer)

[0078] - Duplicate detection (only for UM and AM data transfer)

[0079] - Error detection function (Protocol error detection (only for AM data transfer))

[0080] - RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

[0081] - RLC re-establishment function

[0082] MAC (1b-15, 1b-30) connects to multiple RLC layer devices configured in a single terminal and can perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC can be summarized as follows.

[0083] - Mapping function (Mapping between logical channels and transport channels)

[0084] - Multiplexing and demultiplexing function (Multiplexing / demultiplexing of MAC SDUs belonging to one or different logical channels into / from transport blocks (TB) delivered to / from the physical layer on transport channels)

[0085] - Scheduling information reporting function

[0086] - HARQ function (Error correction through HARQ)

[0087] - Priority handling between logical channels of one UE

[0088] - Priority handling between UEs by means of dynamic scheduling

[0089] - MBMS service identification function

[0090] - Transport format selection function

[0091] - Padding function

[0092] The physical layer (1b-20, 1b-25) can perform operations such as channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it over a wireless channel, or demodulating and channel decoding OFDM symbols received over a wireless channel and transmitting them to a higher layer.

[0093] FIG. 1c is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present invention.

[0094] Referring to FIG. 1c, as illustrated, a wireless access network of a next-generation mobile communication system (hereinafter referred to as NR or 5g) may be composed of a next-generation base station (new radio node B, hereinafter referred to as NR gNB, gNB, NR base station, or base station) (1c-10) and an NR CN (1c-05, new radio core network). A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (1c-15) accesses an external network through the NR gNB (1c-10) and the NR CN (1c-05).

[0095] In Fig. 1c, the NR gNB (1c-10) corresponds to the evolved node B (eNB) (1c-30) of the existing LTE system. The NR gNB (1c-10) is connected to the NR UE (1c-15) via a wireless channel and can provide a service that is superior to the existing node B. In the next-generation mobile communication system, all user traffic is serviced through a shared channel, so a device that collects status information such as buffer status, available transmission power status, and channel status of the UEs (1c-15) and performs scheduling is required, and the NR NB (1c-10) is responsible for this. One NR gNB (1c-10) typically controls multiple cells. In order to implement ultra-high-speed data transmission compared to the current LTE, it can have a bandwidth exceeding the existing maximum, and beamforming technology can be additionally grafted using orthogonal frequency division multiplexing (OFDM) as a wireless access technology. In addition, an adaptive modulation & coding (AMC) method is applied to determine a modulation scheme and a channel coding rate according to the channel status of the terminal (1c-15). The NR CN (1c-05) can perform functions such as mobility support, bearer setup, and QoS setup. The NR CN (1c-05) is a device that is in charge of various control functions as well as mobility management functions for the terminal (1c-15) and can be connected to multiple base stations (1c-10). In addition, the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN (1c-05) can be connected to the MME (1c-25) through a network interface. The MME (1c-25) can be connected to the existing base station, eNB (1c-30).

[0096] FIG. 1d is a diagram illustrating a wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present invention.

[0097] FIG. 1d is a diagram showing the wireless protocol structure of a next-generation mobile communication system to which the present invention can be applied.

[0098] Referring to FIG. 1d, the wireless protocol of the next-generation mobile communication system may be composed of NR SDAP (1d-01, 1d-45), NR PDCP (1d-05, 1d-40), NR RLC (1d-10, 1d-35), NR MAC (1d-15, 1d-30), etc. in a terminal (UE) and an NR base station (NR gNB), respectively.

[0099] Key features of NR SDAP (1d-01, 1d-45) may include some of the following:

[0100] - Transfer of user plane data

[0101] - Mapping function between QoS flow and data bearer for both DL and UL

[0102] - QoS flow ID marking function for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0103] - Ability to map reflective QoS flow to data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0104] For the above SDAP layer device, the terminal can be configured by RRC message for each PDCP layer device, each bearer, or each logical channel, whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device, and when the SDAP header is configured, the terminal can be instructed to update or reset the mapping information for the QoS flow and data bearer of the uplink and downlink with the NAS QoS reflection configuration 1-bit indicator (NAS reflective QoS) and the AS QoS reflection configuration 1-bit indicator (AS reflective QoS) of the SDAP header. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc. to support a smooth service.

[0105] The main functions of NR PDCP (1d-05, 1d-40) may include some of the following functions:

[0106] Header compression and decompression (ROHC only)

[0107] - User data transfer function

[0108] - In-sequence delivery of upper layer PDUs

[0109] - Out-of-sequence delivery of upper layer PDUs

[0110] - PDCP PDU reordering for reception

[0111] - Duplicate detection of lower layer SDUs

[0112] - Retransmission function (Retransmission of PDCP SDUs)

[0113] - Encryption and decryption functions (Ciphering and deciphering)

[0114] - Timer-based SDU discard in uplink.

[0115] The reordering function of the NR PDCP device above refers to a function of reordering PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function of transmitting data to an upper layer in the reordered order, or may include a function of transmitting data directly without considering the order, may include a function of recording lost PDCP PDUs by reordering the order, may include a function of reporting the status of lost PDCP PDUs to the transmitting side, and may include a function of requesting retransmission of lost PDCP PDUs.

[0116] The main features of NR RLC(1d-10, 1d-35) may include some of the following:

[0117] - Data transfer function (Transfer of upper layer PDUs)

[0118] - In-sequence delivery of upper layer PDUs

[0119] - Out-of-sequence delivery of upper layer PDUs

[0120] - ARQ function (Error Correction through ARQ)

[0121] - Concatenation, segmentation and reassembly of RLC SDUs

[0122] - Re-segmentation of RLC data PDUs

[0123] - Reordering of RLC data PDUs

[0124] - Duplicate detection function

[0125] - Protocol error detection

[0126] - RLC SDU discard function

[0127] - RLC re-establishment function

[0128] The in-sequence delivery function of the NR RLC device above refers to the function of sequentially transmitting RLC SDUs received from a lower layer to an upper layer, and may include a function of reassembling and transmitting RLC SDUs when an RLC SDU is originally received divided into multiple RLC SDUs, may include a function of reordering received RLC PDUs based on RLC SN (sequence number) or PDCP SN (sequence number), may include a function of recording lost RLC PDUs by reordering the sequence, may include a function of reporting the status of lost RLC PDUs to the transmitting side, may include a function of requesting retransmission of lost RLC PDUs, may include a function of sequentially transmitting only RLC SDUs up to the lost RLC SDU to an upper layer when there is a lost RLC SDU, or may include a function of sequentially transmitting all RLC SDUs received before the timer starts when a predetermined timer expires even when there is a lost RLC SDU. Or, even if there are lost RLC SDUs, if a predetermined timer has expired, it may include a function to sequentially deliver all RLC SDUs received up to the upper layer. In addition, the RLC PDUs may be processed in the order they are received (in the order of arrival, regardless of the order of the sequence number) and delivered to the PDCP device out of sequence (out-of-sequence delivery). In the case of segments, the segments stored in the buffer or to be received later may be received, reconstructed into a single complete RLC PDU, processed, and then delivered to the PDCP device.The above NR RLC layer may not include a concatenation function, and the function may be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.

[0129] The out-of-sequence delivery function of the NR RLC device above refers to the function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of the order, and may include a function of reassembling and delivering RLC SDUs when an original RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing the RLC SN or PDCP SN of received RLC PDUs and arranging the order to record lost RLC PDUs.

[0130] NR MAC (1d-15, 1d-30) can be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of NR MAC can include some of the following functions.

[0131] - Mapping function (Mapping between logical channels and transport channels)

[0132] - Multiplexing / demultiplexing of MAC SDUs

[0133] - Scheduling information reporting function

[0134] - HARQ function (Error correction through HARQ)

[0135] - Priority handling between logical channels of one UE

[0136] - Priority handling between UEs by means of dynamic scheduling

[0137] - MBMS service identification function

[0138] - Transport format selection function

[0139] - Padding function

[0140] The NR PHY layer (1d-20, 1d-25) can perform operations such as channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it through a wireless channel, or demodulating and channel decoding OFDM symbols received through a wireless channel and transmitting them to a higher layer.

[0141] FIG. 1e is a diagram illustrating a next-generation mobile communication system structure that supports network energy saving according to an embodiment of the present invention.

[0142] Referring to FIG. 1e, a next-generation mobile communication system supporting network energy saving may be composed of a next-generation base station (1e-01, g Node B, hereinafter referred to as gNB, Node B or base station), a sync cell (1e-05, synchronization cell), a data cell (1e-06, 1e-07, 1e-08, data cell), a terminal (1e-09, user equipment (UE), terminal), etc.

[0143] A gNB (1e-01) may be composed of a CU (1e-02, central unit) and one or more DUs (1e-03, 1e-04, distributed units). A CU (1e-02) may support one or more DUs (1e-03, 1e-04), and one DU (1e-03, 1e-04) may support only one or more Sync cells (1e-05), or one or more data cells (1e-06, 1e-07, 1e-08), or one or more Sync cells (1e-05) and one or more data cells (1e-06, 1e-07, 1e-08) simultaneously.

[0144] UE (1e-09) can access an external network via gNB (1e-01) through data cells (1e-06, 1e-07, 1e-08).

[0145] FIG. 1f is a diagram illustrating cells that support network energy saving according to an embodiment of the present invention.

[0146] Referring to FIG. 1f, the Sync cell (1f-01) may be powered on. The state of a powered-on cell may be referred to as active, and the Sync cell (1f-01) according to the present disclosure may always be active. The main functions of the active Sync cell may include some of the following functions.

[0147] - Broadcast of Sync cell-SSB (synchronization signal block)

[0148] - Broadcast of Sync cell-SIB (system information block)

[0149] - short message indicator transmission

[0150] ■ A small message indicator can be transmitted via a CRC (cyclic redundancy check) scrambled DCI (downlink control indicator, downlink control information) using a P-RNTI (paging-radio network temporary identifier). The small message indicator can include at least one of the following:

[0151] ◆ Indicator indicating that only small messages exist in the above DCI

[0152] ◆ An indicator indicating that only paging scheduling information exists in the above DCI.

[0153] ◆ An indicator indicating that both small messages and paging scheduling information exist in the above DCI.

[0154] ◆ Indicator indicating whether a paging message exists

[0155] - short message transmission

[0156] ■ The small message can be transmitted via DCI that is CRC scrambled by P-RNTI. That is, the small message can be transmitted via DCI with the same small message indicator. The small message can include at least one of the following messages.

[0157] ◆ An indicator indicating that certain system information among the synchronous cell system information has been modified.

[0158] ◆ Indicator indicating whether disaster notification is provided among the synchronous cell system information

[0159] ● The above disaster notification may refer to an ETWS (Earthquake & Tsunami Warning System) and / or CMAS (Commercial Mobile Alert Service) notification.

[0160] - Paging message transmission

[0161] - Mobility support of RRC_IDLE and RRC_INACTIVE UE

[0162] As described above, the sync cell (1f-01) can be operated in a low-frequency band (e.g., 700 MHz) that is easy to secure wide coverage in order to transmit a control signal to the terminal (1f-05) and efficiently support the mobility of the terminal in RRC idle mode or RRC deactivation mode.

[0163] Data cells (1f-02, 1f-03, 1f-04) can be operated by being separately equipped with a wake-up receiver (hereinafter WUR) that can receive a wake-up signal (hereinafter WUS) transmitted by a terminal (1f-05) and a transceiver (main transceiver or main radio, hereinafter MR) that can transmit and receive all control signals and data except for the wake-up signal to and from the terminal (1f-05). Since it is difficult to predict when the terminal (1f-05) will transmit the WUS, the data cells (1f-02, 1f-03, 1f-04) can be operated by always turning on the power of the WUR. On the other hand, if the terminal (1f-05) and the data cells (1f-02, 1f-03, 1f-04) do not transmit or receive data for a predetermined period of time, the data cells (1f-02, 1f-03, 1f-04) may have their MRs powered off or on for efficient energy saving. The state of a cell in which the MR power of the data cells (1f-02, 1f-03, 1f-04) is turned off may be referred to as inactive, and the state of a cell in which the MR power of the data cells (1f-02, 1f-03, 1f-04) is turned on may be referred to as active. The data cells (1f-02, 1f-03, 1f-04) according to the present disclosure may be either active data cells or inactive data cells depending on predetermined conditions. For example, a specific data cell (1f-02) may change its state from inactive to active when it receives a WUS (wake-up signal) transmitted by a terminal (1f-05) with a signal strength greater than a certain level. The main functions of the active data cell (1f-02) may include some of the following functions.

[0164] - Receiving a wake-up signal transmitted by the terminal (WUS (wake up signal) reception)

[0165] - Data cell synchronization signal transmission (Broadcast of data cell-SSB (synchronization signal block))

[0166] - Data cell system information transmission (Broadcast of data cell-SIB (system information block))

[0167] - Support of random access procedure

[0168] - Support of RRC_CONNECTED UE and its mobility

[0169] The main functions of the inactive data cell (1f-03, 1f-04) may include some of the following functions:

[0170] - Receiving a wake-up signal transmitted by the terminal (WUS (wake up signal) reception)

[0171] The main functions of the terminal (1f-05) may include some of the following functions.

[0172] - Sync cell selection or reselection for mobility support in RRC idle mode or RRC disabled mode.

[0173] - Reception of paging message transmitted by sync cell

[0174] - Performance of random access procedure with data cell and establishment of RRC connection with data cell

[0175] - Data transmission and reception in data cell and RRC connection mode

[0176] FIG. 1g is an example of a flowchart in which a terminal receives a paging message from a sync cell and establishes or resumes an RRC connection with a data cell in a next-generation mobile communication system that supports network energy saving according to an embodiment of the present invention.

[0177] Referring to FIG. 1g, a terminal (1g-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with active data cell 1 (1g-03) (step 1g-10). At this time, data cell 1 (1g-03) may be in an active state, and the remaining data cells (1g-04, 1g-05) may be in an inactive state.

[0178] In step 1g-15, active data cell 1 (1g-03) may transmit an RRC connection release message (RRCRelease) to terminal (1g-01) to transition the terminal (1g-01) from RRC connected mode to RRC deactivation mode (RRC_INACTIVE) or RRC idle mode (RRC_IDLE). For reference, the active data cell 1 (1g-03) may transmit the message (RRC connection release message) received from a CU in the base station of the cell to the terminal (1g-01). The message may include RRC deactivation mode setting information. The RRC deactivation mode setting information may include at least one of the following:

[0179] - Full Terminal Resumption Identifier (FullI-RNTI)

[0180] ■ An identifier used to identify a reserved terminal context of a terminal (1g-01), which may be composed of x bits (x is an integer greater than 0). The sync cell (1g-02) may use the identifier when transmitting a RAN-initiated paging message when the terminal (1g-01) is in RRC inactive mode in the future.

[0181] -ran-PagingCycle

[0182] ■ A UE-specific paging cycle allocated by a base station to a terminal (1g-01) may be configured with a value of a specific radio frame. The terminal (1g-01) may use this to determine a time point for monitoring a paging occasion.

[0183] - LAN Notification Area Information (ran-NotificationAreaInfo)

[0184] ■Sync cell (1g-02) is set to determine the location of the terminal (1g-01) when the terminal (1g-01) is in RRC deactivation mode, and the area information may be configured with one or more sync cell lists or one or more LAN area settings. The LAN area setting may be configured with at least one of an identifier indicating a mobile communication network to which the terminal (1g-01) has subscribed and a LAN area. The LAN area may be set with one tracking area code (TAC) or with one tracking area code and one or more LAN area codes.

[0185] In step 1g-20, the terminal (1g-01) can transition from RRC connected mode (RRC_CONNECTED) to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE). For example, if the terminal (1g-01) receives an RRC connection release message containing inactive mode setting information in step 1g-15, it can apply the message to transition to RRC inactive mode. If the terminal (1g-01) receives an RRC connection release message without inactive mode setting information in step 1g-15, it can apply the message to transition to RRC idle mode.

[0186] In step 1g-23, active data cell 1 (1g-03) may be changed to an inactive state under certain conditions. For example, active data cell 1 (1g-03) may be changed to an inactive state if it does not receive a certain signal (e.g., a wake-up signal (WUS) transmitted by terminal (1g-01)) from terminal (1g-01) for a certain period of time after transmitting an RRC connection release message.

[0187] In step 1g-25, the RRC disabled mode or RRC idle mode terminal (1g-01) can receive a synchronization signal (Sync cell-Synchronization signal block, hereinafter referred to as Sync cell-SSB) transmitted by the Sync cell (1g-02). Then, the terminal (1g-01) can select or camp on the Sync cell (1g-02) (step 1g-30). For example, the terminal (1g-01) can camp on the Sync cell (1g-02) when the Sync cell selection reception signal derived from the received Sync cell-SSB and the signal quality are greater than a predetermined threshold value.

[0188] In step 1g-31, the terminal (1g-01) can receive sync cell system information (Sync cell-system information block, hereinafter referred to as Sync cell-SIB) transmitted by the sync cell (1g-02). Then, the terminal (1g-01) can perform a sync cell reselection procedure (step 1g-32).

[0189] According to an embodiment, the Sync cell-SSB (1g-25) and the Sync cell-SIB (1g-31) may be transmitted periodically. In the present disclosure, at least one of the following information may be included and transmitted through at least one of the Sync cell-SSB and the Sync cell-SIB.

[0190] - Time / frequency resource information for the terminal (1g-01) to transmit a wake-up signal (WUS) (time / frequency resource for WUS)

[0191] - Setting information required to select or reselect a sync cell

[0192] ■ One or more sync cell identifiers

[0193] ■ One or more frequencies on which sync cells operate

[0194] ■ Cell reselection priority by sync cell frequency

[0195] ■ Parameters or threshold values ​​required to select or reselect a sync cell

[0196] - Information about each sync cell and the data cell associated with each sync cell (e.g., data cell identifier, data area code, etc.)

[0197] - Configuration information required to receive DCI containing at least one of a small message indicator, a small message, and paging message scheduling information.

[0198] - Configuration information required to receive paging messages

[0199] In step 1g-35, the RRC disabled mode or RRC idle mode terminal (1g-01) can monitor a paging occasion according to a specific cycle. That is, the terminal (1g-01) can monitor a paging occasion to receive scheduling information for receiving a paging message that the Sync cell (1g-02) will transmit later. Specifically, the terminal (1g-01) can monitor a paging occasion to receive a DCI whose CRC is scrambled by the P-RNTI from the Sync cell (1g-02) to receive scheduling information for receiving a paging message.

[0200] In step 1g-40, an RRC disabled mode or RRC idle mode terminal (1g-01) can receive a paging message transmitted by a sync cell (1g-02). The paging message can include a paging record containing a terminal identifier (e.g., a paging terminal identifier, PagingUE-Identity) for paging the terminal (1g-01). In this case, if the paging message is a RAN-initiated paging message, the terminal identifier can mean a terminal identifier that can identify the RRC disabled mode terminal (e.g., a complete terminal connection resumption identifier contained in an RRC connection release message). In case of a CN-initiated paging message, the terminal identifier is a terminal identifier provided by the core network to the terminal (1g-01), and may mean a temporary terminal identifier (e.g., 5G S-Temporary Mobile Subscription Identifier, 5G-S-TMSI) that can uniquely identify the RRC idle mode terminal within a specific area (e.g., tracking area). For reference, the sync cell (1g-02) may transmit the message (paging message) received from the CU in the base station of the cell to the terminal (1g-01). The CU in the base station may additionally transmit some of the message or the information contained in the message to data cells (1g-03, 1g-04, 1g-05). This is to enable the terminal (1g-01) to know that the RRC connection is established due to paging when it attempts to establish an RRC connection with the data cell (1g-03, 1g-04, 1g-05) in the future.

[0201] In step 1g-45, an RRC idle mode or RRC disabled mode terminal (1g-01) can transmit a wake-up signal (WUS) to wake up an inactive data cell. The wake-up signal transmitted by the terminal (1g-01) may be a dedicated signal for waking up only a specific inactive data cell, or may be a common signal for commonly waking up all inactive data cells (or all inactive data cells associated with a specific Sync cell). For reference, in order to save network energy, among the inactive data cells (1g-03, 1g-04, 1g-05) that have received a WUS, only the inactive data cell (1g-03) that satisfies a certain condition may be powered on and become an active data cell (1g-46). For example, when the WUS reception signal strength is greater than a certain threshold value, or through negotiation between the data cells that have received the WUS, only the data cell that has the strongest signal for receiving the WUS may wake up and become an active data cell. Note that step 1g-45 may be performed even if there are active data cells.

[0202] In step 1g-50, an RRC idle mode or RRC deactivation mode terminal (1g-01) can select active data cell 1 (1g-03) (step 1g-51) by receiving a data cell synchronization signal (Data cell-SSB) and / or data cell system information (Data cell-SIB) transmitted by active data cell 1 (1g-03).

[0203] In step 1g-55, the RRC idle mode or RRC disabled mode terminal (1g-01) can establish an RRC connection with active data cell 1 (1g-03). For example, when the terminal (1g-01) is in RRC idle mode, the RRC connection can be established by performing an RRC connection establishment procedure with the active data cell 1 (1g-03). When the terminal (1g-01) is in RRC disabled mode, the RRC connection can be established by performing an RRC connection resume procedure with the active data cell 1 (1g-03).

[0204] A sync cell (1g-02) according to the present disclosure has the characteristic of transmitting a paging message to a terminal (1g-01) but not establishing a direct RRC connection with the terminal (1g-01). On the other hand, a data cell (1g-03) has the characteristic of not transmitting a paging message to the terminal (1g-01) but establishing a direct RRC connection with the terminal (1g-01).

[0205] A terminal (1g-01) according to the present disclosure receives a paging message transmitted by a sync cell (1g-02), and, if the paging message includes a paging terminal identifier for waking up the terminal (1g-01), transmits a wake-up signal to data cells (1g-03, 1g-04, 1g-05) to establish an RRC connection with the data cell (1g-03).

[0206] FIG. 1h is another example of a flowchart in which a terminal receives a paging message from a sync cell and establishes or resumes an RRC connection with a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0207] Referring to FIG. 1h, the terminal (1h-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with active data cell 1 (1h-03) (step 1h-10). At this time, the data cell 1 (1h-03) may be in an active state, and the remaining data cells (1h-04, 1h-05) may be in an inactive state.

[0208] At step 1h-15, active data cell 1 (1h-03) may transmit an RRC connection release message (RRCRelease) to terminal (1h-01) to transition the terminal (1h-01) from RRC connected mode to RRC deactivation mode (RRC_INACTIVE) or RRC idle mode (RRC_IDLE). For reference, the active data cell 1 (1h-03) may transmit the message (RRC connection release message) received from a CU in the base station of the cell to the terminal (1h-01). The message may include RRC deactivation mode setting information. The RRC deactivation mode setting information may include at least one of the following:

[0209] - Full Terminal Resumption Identifier (FullI-RNTI)

[0210] ■ An identifier used to identify a reserved terminal context of a terminal (1h-01), which may be composed of x bits (x is an integer greater than 0). The sync cell (1h-02) may use the identifier when transmitting a RAN-initiated paging message when the terminal (1h-01) is in RRC inactive mode in the future.

[0211] -ran-PagingCycle

[0212] ■ A UE-specific paging cycle allocated by a base station to a terminal (1h-01) and may be configured with a value of a specific radio frame. The terminal (1h-01) may use this to determine a time point for monitoring a paging occasion.

[0213] - LAN Notification Area Information (ran-NotificationAreaInfo)

[0214] ■ Sync cell (1h-02) is set to determine the location of the terminal (1h-01) when the terminal (1h-01) is in RRC deactivation mode, and the area information may be configured with one or more Sync cell lists or one or more LAN area settings. The LAN area setting may be configured with at least one of an identifier indicating a mobile communication network to which the terminal (1h-01) has subscribed and a LAN area. The LAN area may be set with one tracking area code (TAC) or one tracking area code and one or more LAN area codes.

[0215] In step 1h-20, the terminal (1h-01) can transition from RRC connected mode (RRC_CONNECTED) to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE). For example, if the terminal (1h-01) receives an RRC connection release message containing inactive mode setting information in step 1h-15, it can apply the message to transition to RRC inactive mode. If the terminal (1h-01) receives an RRC connection release message without inactive mode setting information in step 1h-15, it can apply the message to transition to RRC idle mode.

[0216] In step 1h-23, active data cell 1 (1h-03) may be changed to an inactive state under certain conditions. For example, active data cell 1 (1h-03) may be changed to an inactive state if it does not receive a certain signal (e.g., a wake-up signal (WUS) transmitted by terminal (1h-01)) from terminal (1h-01) for a certain period of time after transmitting an RRC connection release message.

[0217] At step 1h-25, the RRC deactivation mode or RRC idle mode terminal (1h-01) can receive a synchronization signal (Sync cell-SSB) transmitted by a Sync cell (1h-02). Then, the terminal (1h-01) can select or camp on the Sync cell (1h-02) (step 1h-30). For example, the terminal (1h-01) can camp on the Sync cell (1h-02) if the Sync cell selection reception signal derived from the received Sync cell-SSB and the signal quality are greater than a predetermined threshold value.

[0218] In step 1h-31, the terminal (1h-01) can receive sync cell system information (Sync cell-SIB) transmitted by the sync cell (1h-02). Then, the terminal (1h-01) can perform a sync cell reselection procedure (step 1h-32).

[0219] According to an embodiment, the Sync cell-SSB (1h-25) and the Sync cell-SIB (1h-31) may be transmitted periodically. In the present disclosure, at least one of the following information may be included and transmitted through at least one of the Sync cell-SSB and the Sync cell-SIB.

[0220] - Time / frequency resource information for the terminal (1h-01) to transmit a wake-up signal (WUS) (time / frequency resource for WUS)

[0221] - Setting information required to select or reselect a sync cell

[0222] ■ One or more sync cell identifiers

[0223] ■ One or more frequencies on which sync cells operate

[0224] ■ Cell reselection priority by sync cell frequency

[0225] ■ Parameters or threshold values ​​required to select or reselect a sync cell

[0226] - Information about each sync cell and the data cell associated with each sync cell (e.g., data cell identifier, data area code, etc.)

[0227] - Configuration information required to receive DCI containing at least one of a small message indicator, a small message, and paging message scheduling information.

[0228] - Configuration information required to receive paging messages

[0229] In step 1h-33, a given terminal (1h-06) can transmit a wake-up signal (WUS) to wake up an inactive data cell. The wake-up signal transmitted by the terminal (1h-06) may be a dedicated signal for waking up only a specific inactive data cell, or may be a common signal for commonly waking up all inactive data cells (or all inactive data cells associated with a specific Sync cell). Among the inactive data cells (1h-03, 1h-04, 1h-05), all inactive data cells (1h-03, 1h-04, 1h-05) that receive a WUS may be powered on and become active data cells, or only inactive data cells that satisfy a predetermined condition (e.g., when the WUS reception signal strength is greater than a specific threshold value) may be converted into active data cells. In the present disclosure, for convenience of explanation, inactive data cell 1 (1h-03) may be switched to an active state (1h-35), inactive data cell 2 (1h-04) may be switched to an active state (1h-36), and data cell 3 (1h-04) may continue to maintain an inactive state.

[0230] In step 1h-40, active data cell 1 (1h-03) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1h-01).

[0231] In step 1h-41, active data cell 2 (1h-04) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1h-01).

[0232] In step 1h-45, the RRC disabled mode or RRC idle mode terminal (1h-01) can monitor a paging occasion according to a specific cycle. That is, the terminal (1h-01) can monitor a paging occasion to receive scheduling information for receiving a paging message that the Sync cell (1h-02) will transmit later. Specifically, the terminal (1h-01) can monitor a paging occasion to receive a DCI whose CRC is scrambled by the P-RNTI from the Sync cell (1h-02) to receive scheduling information for receiving a paging message.

[0233] In step 1h-50, an RRC deactivation mode or RRC idle mode terminal (1h-01) can receive a paging message transmitted by a sync cell (1h-02). The paging message can include a paging record containing a terminal identifier (e.g., a paging terminal identifier, PagingUE-Identity) for paging the terminal. In this case, if the paging message is a RAN-initiated paging message, the terminal identifier can mean a terminal identifier that can identify the RRC deactivation mode terminal (e.g., a complete terminal connection resumption identifier contained in an RRC connection release message). In case of a CN-initiated paging message, the terminal identifier is a terminal identifier provided by the core network to the terminal (1h-01), and may mean a temporary terminal identifier (e.g., 5G S-Temporary Mobile Subscription Identifier, 5G-S-TMSI) that can uniquely identify the RRC idle mode terminal within a specific area (e.g., tracking area). For reference, the Sync cell (1h-02) may transmit the message (paging message) received from the CU in the base station of the cell to the terminal (1h-01). The CU in the base station may additionally transmit some of the message or the information contained in the message to data cells (1h-03, 1h-04, 1h-05). This is to enable the terminal (1h-01) to know that the RRC connection is established due to paging when it attempts to establish an RRC connection with the data cell (1h-03, 1h-04, 1h-05) in the future.

[0234] In step 1h-51, the RRC idle mode or RRC deactivation mode terminal (1h-01) can select (1h-51) active data cell 1 (1h-03). The terminal (1h-01) can select the active data cell 1 (1h-03) based on the data cell-SSB and / or data cell-SIB transmitted by the active data cells (1h-03, 1h-04). For reference, if step 1h-51 cannot be performed (e.g., if an appropriate active data cell cannot be selected), the terminal (1h-01) may select an active data cell by transmitting a WUS as in the above-described embodiment. That is, if an active data cell can be selected, the terminal (1h-01) may not transmit a WUS separately.

[0235] At step 1h-55, the RRC idle mode or RRC deactivation mode terminal (1h-01) can establish an RRC connection with active data cell 1 (1h-03). For example, when the terminal (1h-01) is in RRC idle mode, the RRC connection can be established by performing an RRC connection establishment procedure with the active data cell 1 (1h-03). When the terminal (1h-01) is in RRC deactivation mode, the RRC connection can be established by performing an RRC connection resume procedure with the active data cell 1 (1h-03).

[0236] A sync cell (1h-02) according to the present disclosure has the characteristic of transmitting a paging message to a terminal (1h-01) but not establishing a direct RRC connection with the terminal (1h-01). On the other hand, a data cell has the characteristic of not transmitting a paging message to the terminal (1h-01) but establishing a direct RRC connection with the terminal (1h-01).

[0237] A terminal (1h-01) according to the present disclosure has a feature of receiving a paging message transmitted by a sync cell (1h-02), and determining whether an active data cell (1h-03, 1h-04) can be selected without separately transmitting a wake-up signal if the paging message includes a paging terminal identifier for waking up the terminal (1h-01). That is, if the terminal (1h-01) according to the present disclosure can select an active data cell (1h-03), the terminal can establish an RRC connection with the selected active data cell (1h-03), and if not (if the active data cell cannot be selected or if there is no active data cell), the terminal can transmit a wake-up signal to the data cell (1h-03, 1h-04) to establish an RRC connection with the data cell (1h-03).

[0238] FIG. 1i is another example of a flowchart in which a terminal receives a paging message from a sync cell and establishes or resumes an RRC connection with a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0239] Referring to FIG. 1i, the terminal (1i-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with active data cell 1 (1i-03) (step 1i-10). At this time, the data cell 1 (1i-03) may be in an active state, and the remaining data cells (1i-04, 1i-05) may be in an inactive state.

[0240] In step 1i-15, active data cell 1 (1i-03) may transmit an RRC connection release message (RRCRelease) to terminal (1i-01) to transition the terminal (1i-01) from RRC connected mode to RRC deactivation mode (RRC_INACTIVE) or RRC idle mode (RRC_IDLE). For reference, the active data cell 1 (1i-03) may transmit the message (RRC connection release message) received from a CU in the base station of the cell to the terminal (1i-01). The message may include RRC deactivation mode setting information. The RRC deactivation mode setting information may include at least one of the following:

[0241] - Full Terminal Resumption Identifier (FullI-RNTI)

[0242] ■ An identifier used to identify a reserved terminal context of a terminal (1i-01), which may be composed of x bits (x is an integer greater than 0). The sync cell (1i-02) may use the identifier when transmitting a RAN-initiated paging message when the terminal is in RRC inactive mode in the future.

[0243] -ran-PagingCycle

[0244] ■ A UE-specific paging cycle allocated by a base station to a terminal (1i-01) may be configured with a value of a specific radio frame. The terminal (1i-01) may use this to determine a time point for monitoring a paging occasion.

[0245] - LAN Notification Area Information (ran-NotificationAreaInfo)

[0246] ■ Sync cell (1i-02) is set to determine the location of the terminal (1i-01) when the terminal (1i-01) is in RRC deactivation mode, and the area information may be configured with one or more Sync cell lists or one or more LAN area settings. The LAN area setting may be configured with at least one of an identifier indicating a mobile communication network to which the terminal (1i-01) has subscribed and a LAN area. The LAN area may be set with one tracking area code (TAC) or one tracking area code and one or more LAN area codes.

[0247] In step 1i-20, the terminal (1i-01) can transition from RRC connected mode (RRC_CONNECTED) to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE). For example, if the terminal (1i-01) receives an RRC connection release message containing inactive mode setting information in step 1i-15, it can apply the message to transition to RRC inactive mode. If the terminal (1i-01) receives an RRC connection release message without inactive mode setting information in step 1i-15, it can apply the message to transition to RRC idle mode.

[0248] In step 1i-23, active data cell 1 (1i-03) may be changed to an inactive state under certain conditions. For example, active data cell 1 (1i-03) may be changed to an inactive state if it does not receive a certain signal (e.g., a wake-up signal (WUS) transmitted by terminal (1i-01)) from terminal (1i-01) for a certain period of time after transmitting an RRC connection release message.

[0249] In step 1i-25, the RRC disabled mode or RRC idle mode terminal (1i-01) can receive a synchronization signal (Sync cell-SSB) transmitted by the Sync cell (1i-02). Then, the terminal (1i-01) can select or camp on the Sync cell (1i-02) (step 1i-30). For example, the terminal (1i-01) can camp on the Sync cell (1i-02) if the Sync cell selection reception signal derived from the received Sync cell-SSB and the signal quality are greater than a predetermined threshold value.

[0250] In step 1i-31, the terminal (1i-01) can receive sync cell system information (Sync cell-SIB) transmitted by the sync cell (1i-02). Then, the terminal (1i-01) can perform a sync cell reselection procedure (step 1i-32).

[0251] According to an embodiment, the Sync cell-SSB (1i-25) and the Sync cell-SIB (1i-31) may be transmitted periodically. In the present disclosure, at least one of the following information may be included and transmitted through at least one of the Sync cell-SSB and the Sync cell-SIB.

[0252] - Time / frequency resource information for the terminal (1i-01) to transmit a wake-up signal (WUS) (time / frequency resource for WUS)

[0253] - Setting information required to select or reselect a sync cell

[0254] ■ One or more sync cell identifiers

[0255] ■ One or more frequencies on which sync cells operate

[0256] ■ Cell reselection priority by sync cell frequency

[0257] ■ Parameters or thresholds required to select or reselect a sync cell

[0258] - Information about each sync cell and the data cells associated with each sync cell (e.g., data cell identifier, data area code, etc.)

[0259] - Configuration information required to receive DCI containing at least one of a small message indicator, a small message, and paging message scheduling information.

[0260] - Configuration information required to receive paging messages

[0261] In step 1i-35, the RRC disabled mode or RRC idle mode terminal (1i-01) can monitor a paging occasion according to a specific cycle. That is, the terminal (1i-01) can monitor a paging occasion to receive scheduling information for receiving a paging message that the Sync cell (1i-02) will transmit later. Specifically, the terminal (1i-01) can monitor a paging occasion to receive a DCI whose CRC is scrambled by the P-RNTI from the Sync cell (1i-02) to receive scheduling information for receiving a paging message.

[0262] In step 1i-37, the RRC inactive mode or RRC idle mode terminal (1i-01) can transmit a wake-up signal (WUS). The wake-up signal transmitted by the terminal (1i-01) may be a dedicated signal for waking up only a specific inactive data cell, or may be a common signal for waking up all inactive data cells (or all inactive data cells associated with a specific sync cell). All inactive data cells that have received a WUS may become active. Alternatively, among the inactive data cells that have received a WUS, only inactive data cells that meet a predetermined condition (for example, when the WUS reception signal strength is greater than a specific threshold value) may be converted to active data cells. In the present disclosure, for convenience of explanation, inactive data cell 1 (1i-03) can be switched to an active state (1i-38), inactive data cell 2 (1i-04) can be switched to an active state (1i-39), and data cell 3 (1i-04) can continue to maintain an inactive state.

[0263] Depending on the embodiment, the RRC disabled mode or RRC idle mode terminal (1i-01) may not perform step 1i-37. For example, if active data cells are transmitting data cell-SSB and / or data cell-SIB and the terminal (1i-01) can select an active data cell, the terminal (1i-01) may not transmit a separate wake-up signal.

[0264] In step 1i-40, an RRC disabled mode or RRC idle mode terminal (1i-01) can receive a paging message transmitted by a sync cell (1i-02). The paging message can include a paging record containing a terminal identifier (e.g., a paging terminal identifier, PagingUE-Identity) for paging the terminal (1i-01). In this case, if the paging message is a RAN-initiated paging message, the terminal identifier can mean a terminal identifier that can identify the RRC disabled mode terminal (e.g., a complete terminal connection resumption identifier contained in an RRC connection release message). In case of a CN-initiated paging message, the terminal identifier is a terminal identifier provided by the core network to the terminal (1i-01), and may mean a temporary terminal identifier (e.g., 5G S-Temporary Mobile Subscription Identifier, 5G-S-TMSI) that can uniquely identify the RRC idle mode terminal within a specific area (e.g., tracking area). For reference, the sync cell (1i-02) may transmit the message (paging message) received from the CU in the base station of the cell to the terminal (1i-01). The CU in the base station may additionally transmit some of the message or the information contained in the message to data cells (1i-03, 1i-04, 1i-05). This is to enable the terminal (1i-01) to know that the RRC connection is established due to paging when it wants to establish an RRC connection with the data cell (1i-03, 1i-04, 1i-05) in the future.

[0265] In step 1i-43, active data cell 1 (1i-03) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1i-01). Step 1i-43 may also be performed before step 1i-40.

[0266] In step 1i-44, active data cell 2 (1i-04) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1i-01). Step 1i-44 may also be performed before step 1i-40.

[0267] In step 1i-50, an RRC idle mode or RRC deactivation mode terminal (1i-01) can select active data cell 1 (1i-03). The terminal (1i-01) can select active data cell 1 (1i-03) based on data cell-SSB and / or data cell-SIB transmitted by active data cells (1i-03, 1i-04).

[0268] At step 1i-55, the RRC idle mode or RRC deactivation mode terminal (1i-01) can establish an RRC connection with active data cell 1 (1i-03). For example, when the terminal (1i-01) is in RRC idle mode, the RRC connection can be established by performing an RRC connection establishment procedure with the active data cell 1 (1i-03). When the terminal (1i-01) is in RRC deactivation mode, the RRC connection can be established by performing an RRC connection resume procedure with the active data cell 1 (1i-03).

[0269] A sync cell (1i-02) according to the present disclosure has the characteristic of transmitting a paging message to a terminal (1i-01) but not establishing a direct RRC connection with the terminal (1i-01). On the other hand, a data cell has the characteristic of not transmitting a paging message to the terminal (1i-01) but establishing a direct RRC connection with the terminal (1i-01).

[0270] A terminal (1i-01) according to the present disclosure has a feature of transmitting a wake-up signal to data cells (1i-03, 1i-03, 1i-05) after receiving paging scheduling information contained in a short message indicator transmitted by a sync cell (1i-02). Specifically, before monitoring or receiving a paging message transmitted by a sync cell (1i-02), the terminal (1i-01) can quickly wake up inactive data cells (1i-03, 1i-03, 1i-05), and the paged terminal (1i-01) can quickly select the corresponding active data cell (1i-03) to quickly establish an RRC connection.

[0271] FIG. 1J is a diagram illustrating cells that support network energy saving according to an embodiment of the present invention.

[0272] Referring to FIG. 1j, the Sync cell (1j-01) may be powered on. The state of a powered-on cell may be referred to as active, and the Sync cell (1j-01) according to the present disclosure may always be active. The main functions of the active Sync cell may include some of the following functions.

[0273] - Broadcast of Sync cell-SSB (Synchronization signal block)

[0274] - Broadcast of Sync cell-SIB (system information block)

[0275] - short message indicator transmission

[0276] ■ A small message indicator may be transmitted via DCI CRC-scrambled by the P-RNTI. The small message indicator may include at least one of the following:

[0277] ◆ Indicator indicating that only small messages exist in the above DCI

[0278] ◆ An indicator indicating that only paging scheduling information exists in the above DCI.

[0279] ◆ An indicator indicating that both small messages and paging scheduling information exist in the above DCI.

[0280] ◆ Indicator indicating whether a paging message exists

[0281] ◆ Shortened UE ID that can identify the terminal

[0282] ● A short terminal identifier may mean an identifier composed of some information among the terminal identifiers applied to the paging terminal identifier.

[0283] ● When a short terminal identifier is received, the associated terminal can receive a paging message by monitoring the paging channel from the data cell.

[0284] ● The above short terminal identifier may be an identifier set for a specific terminal by a base station or core network, or may be an identifier derived by the terminal itself using a specific formula.

[0285] - short message transmission

[0286] ■ The small message can be transmitted via DCI that is CRC scrambled by P-RNTI. That is, the small message can be transmitted via DCI with the same small message indicator. The small message can include at least one of the following messages.

[0287] ◆ An indicator indicating that certain system information among the synchronous cell system information has been modified.

[0288] ◆ Indicator indicating whether disaster notification is provided among the synchronous cell system information

[0289] ● The above disaster notification may refer to an ETWS (Earthquake & Tsunami Warning System) and / or CMAS (Commercial Mobile Alert Service) notification.

[0290] - Mobility support of RRC_IDLE and RRC_INACTIVE UE

[0291] As described above, the Sync cell (1j-01) can be operated in a low-frequency band (e.g., 700 MHz) that is easy to secure wide coverage in order to transmit a control signal to the terminal and efficiently support the mobility of the terminal in RRC idle mode or RRC deactivation mode. The Sync cell (1j-01) can receive a small message indicator and a short message from a CU in the base station and transmit them to the terminal. For reference, when the CU transmits a small message indicator and a short message to the Sync cell (1j-01), the CU can also transmit necessary information to the data cells (1j-02, 1j-03, 1j-04). For example, the CU may forward the paging terminal identifier associated with the short terminal identifier included in the small message indicator to the data cell (1j-02, 1j-03, 1j-04) or may forward the paging record or paging message to the data cell (1j-02, 1j-03, 1j-04).

[0292] Data cells (1j-02, 1j-03, 1j-04) can be operated by being separately equipped with a receiver (Wake-Up Receiver, hereinafter WUR) that can receive a wake-up signal (WUS) transmitted by a terminal (1j-05) and a transceiver (main transceiver or main radio, hereinafter MR) that can transmit and receive all control signals and data except for the WUS to and from the terminal (1j-05). Since it is difficult to predict when the terminal (1j-05) will transmit the WUS, the data cells (1j-02, 1j-03, 1j-04) can be operated by always turning on the power of the WUR. On the other hand, if the terminal (1j-01) and the data cell do not transmit or receive data for a predetermined period of time, the data cells (1j-02, 1j-03, 1j-04) may turn off or turn on the MR power for efficient energy saving. The state of a cell in which the MR power of the data cell is turned off may be referred to as inactive, and the state of a cell in which the MR power of the data cell is turned on may be referred to as active. The data cells (1j-02, 1j-03, 1j-04) according to the present disclosure may be active data cells or inactive data cells according to predetermined conditions. For example, a specific data cell (1j-02) may change its state from inactive to active when it receives a WUS transmitted by the terminal (1j-05) with a signal strength higher than a specific signal strength. The main functions of the active data cell (1j-02) may include some of the following functions.

[0293] - Receiving a wake-up signal transmitted by the terminal (WUS (wake up signal) reception)

[0294] - Data cell synchronization signal transmission (Broadcast of data cell-SSB (Synchronization signal block))

[0295] - Data cell system information transmission (Broadcast of data cell-SIB (system information block))

[0296] - Support of random access procedure

[0297] - Support of RRC_CONNECTED UE and its mobility

[0298] - Transmission of paging message

[0299] ■ Data cells (1j-02, 1j-03, 1j-04) can transmit a paging message to a terminal (1j-05) by receiving the paging message from a CU within the base station.

[0300] The main functions of the inactive data cell (1j-03, 1j-04) may include some of the following functions:

[0301] - Receiving a wake-up signal transmitted by the terminal (WUS (wake up signal) reception)

[0302] The main functions of the terminal (1j-05) may include some of the following functions:

[0303] - Sync cell selection or reselection for mobility support in RRC idle mode or RRC disabled mode.

[0304] - Reception of short message indicator transmitted by sync cell

[0305] - Reception of paging message transmitted by data cell

[0306] - Transmission of Wake-Up Signal

[0307] ■ The above wake-up signal can be transmitted to switch an inactive data cell to an active state.

[0308] ■ The above wake-up signal may include an instruction to transmit a paging message to the data cell.

[0309] - Performance of random access procedure with data cell and establishment of RRC connection with data cell

[0310] - Data transmission and reception in data cell and RRC connection mode

[0311] FIG. 1k is a flowchart illustrating a process in which a terminal receives a small message indicator from a sync cell and a page message from a data cell to establish or resume an RRC connection with a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0312] Referring to FIG. 1k, the terminal (1k-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with active data cell 1 (1k-03) (step 1k-10). At this time, the data cell 1 (1k-03) may be in an active state, and the remaining data cells (1k-04, 1k-05) may be in an inactive state.

[0313] In step 1k-15, active data cell 1 (1k-03) may transmit an RRC connection release message (RRCRelease) to terminal (1k-01) to transition the terminal (1k-01) from RRC connected mode to RRC deactivation mode (RRC_INACTIVE) or RRC idle mode (RRC_IDLE). For reference, the active data cell 1 (1k-03) may transmit the message (RRC connection release message) received from a CU in a base station of the cell to the terminal (1k-01). The message may include a short terminal identifier. The message may include some information among the paging terminal identifiers for the terminal (1k-01). The message may include RRC deactivation mode setting information. The RRC deactivation mode setting information may include at least one of the following:

[0314] - Full Terminal Resumption Identifier (FullI-RNTI)

[0315] ■ An identifier used to identify a reserved terminal context of a terminal (1k-01), which may be composed of x bits (x is an integer greater than 0). The sync cell (1k-02) may use the identifier when transmitting a RAN-initiated paging message when the terminal (1k-01) is in RRC inactive mode in the future.

[0316] -ran-PagingCycle

[0317] ■ A UE-specific paging cycle allocated by a base station to a terminal (1k-01) may be configured with a value of a specific radio frame. The terminal (1k-01) may use this to determine a time point for monitoring a paging occasion.

[0318] - LAN Notification Area Information (ran-NotificationAreaInfo)

[0319] ■ Sync cell (1k-02) is set to determine the location of the terminal (1k-01) when the terminal (1k-01) is in RRC deactivation mode, and the area information may be configured with one or more Sync cell lists or one or more LAN area settings. The LAN area setting may be configured with at least one of an identifier indicating a mobile communication network to which the terminal (1k-01) has subscribed and a LAN area. The LAN area may be set with one tracking area code or with one tracking area code and one or more LAN area codes.

[0320] In step 1k-20, the terminal (1k-01) can transition from RRC connected mode (RRC_CONNECTED) to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE). For example, if the terminal (1k-01) receives an RRC connection release message containing inactive mode setting information in step 1k-15, it can apply the message to transition to RRC inactive mode. If the terminal (1k-01) receives an RRC connection release message without inactive mode setting information in step 1k-15, it can apply the message to transition to RRC idle mode.

[0321] In step 1k-23, active data cell 1 (1k-03) may be changed to an inactive state under certain conditions. For example, active data cell 1 (1k-03) may be changed to an inactive state if it does not receive a certain signal (e.g., a wake-up signal (WUS) transmitted by terminal (1k-01)) from terminal (1k-01) for a certain period of time after transmitting an RRC connection release message.

[0322] At step 1k-25, the RRC disabled mode or RRC idle mode terminal (1k-01) can receive a synchronization signal (Sync cell-SSB) transmitted by a Sync cell (1k-02). Then, the terminal (1k-01) can select or camp on the Sync cell (1k-02) (step 1k-30). For example, the terminal (1k-01) can camp on the Sync cell (1k-02) if the Sync cell selection reception signal derived from the received Sync cell-SSB and the signal quality are greater than a predetermined threshold value.

[0323] In step 1k-31, the terminal (1k-01) can receive sync cell system information (Sync cell-SIB) transmitted by the sync cell (1k-02). Then, the terminal (1k-01) can perform a sync cell reselection procedure (step 1k-32).

[0324] According to an embodiment, the Sync cell-SSB (1k-25) and the Sync cell-SIB (1k-31) may be transmitted periodically. In the present disclosure, at least one of the following information may be included and transmitted through at least one of the Sync cell-SSB and the Sync cell-SIB.

[0325] - Time / frequency resource information for the terminal (1k-01) to transmit a wake-up signal (WUS) (time / frequency resource for WUS)

[0326] - Setting information required to select or reselect a sync cell

[0327] ■ One or more sync cell identifiers

[0328] ■ One or more frequencies on which sync cells operate

[0329] ■ Cell reselection priority by sync cell frequency

[0330] ■ Parameters or threshold values ​​required to select or reselect a sync cell

[0331] - Information about each sync cell and the data cell associated with each sync cell (e.g., data cell identifier, data area code, etc.)

[0332] - Configuration information required to receive DCI containing at least one of a small message indicator, a small message, and paging message scheduling information.

[0333] - Configuration information required to receive paging messages

[0334] In step 1k-35, the RRC disabled mode or RRC idle mode terminal (1k-01) can monitor paging occasions at specific intervals. This allows the terminal (1k-01) to receive a small message indicator. The small message indicator may include at least one of the following pieces of information:

[0335] - Indicator indicating whether a paging message exists

[0336] - Shortened UE ID that can identify the above terminal (1k-01)

[0337] - Some terminal identifier values ​​among the paging terminal identifiers used to page the terminal (1k-01) in the paging record stored in the paging message

[0338] Specifically, the terminal (1k-01) can receive the small message indicator by monitoring a paging opportunity and receiving a DCI with a CRC scrambled by a P-RNTI from a sync cell (1k-02).

[0339] In step 1k-37, the RRC disabled mode or RRC idle mode terminal (1k-01) can transmit a wake-up signal (WUS). The wake-up signal transmitted by the terminal (1k-01) can be a dedicated signal for waking up only a specific inactive data cell, or can be a common signal for waking up all inactive data cells (or all inactive data cells associated with a specific sync cell). All inactive data cells that have received a WUS can become active. Alternatively, among the inactive data cells that have received a WUS, only inactive data cells that meet a predetermined condition (for example, when the WUS reception signal strength is greater than a specific threshold value) can be converted to active data cells. In the present disclosure, for convenience of explanation, inactive data cell 1 (1k-03) may be switched to an active state (1k-38), inactive data cell 2 (1k-04) may be switched to an active state (1k-39), and data cell 3 (1k-04) may remain in an inactive state. The WUS may include an instruction to transmit a paging message or some information from the small message instruction received in step 1k-35. The terminal (1k-01) may monitor a paging channel from a data cell and transmit a WUS to receive a paging message.

[0340] Depending on the embodiment, the RRC disabled mode or RRC idle mode terminal (1k-01) may not perform step 1k-37. For example, if the active data cells are transmitting data cell-SSB and / or data-cell SIB, and thus the terminal (1k-01) can select the active data cell, the terminal (1k-01) may not transmit a separate wake-up signal.

[0341] In step 1k-43, active data cell 1 (1k-03) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1k-01). Step 1k-43 may also be performed before step 1k-37.

[0342] In step 1k-44, active data cell 2 (1k-04) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1k-01). Step 1k-44 may also be performed before step 1k-37.

[0343] At step 1k-50, an RRC idle mode or RRC deactivation mode terminal (1k-01) can select active data cell 1 (1k-03). The terminal (1k-01) can select active data cell 1 (1k-03) based on data cell-SSB and / or data cell-SIB transmitted by active data cells (1k-03, 1k-04).

[0344] In step 1k-55, the RRC deactivation mode or RRC idle mode terminal (1k-01) can receive a paging message transmitted by active data cell 1 (1k-03). The paging message can include a paging record containing a terminal identifier (e.g., a paging terminal identifier, PagingUE-Identity) for paging the terminal (1k-01). In this case, if the paging message is RAN-initiated, the terminal identifier can mean a terminal identifier that can identify the RRC deactivation mode terminal (e.g., a complete terminal connection resumption identifier contained in an RRC connection release message). In case of a paging message initiated by a core network (CN-initiated), the terminal identifier is a terminal identifier provided by the core network to the terminal (1k-01), and may mean a temporary terminal identifier (e.g., 5G S-Temporary Mobile Subscription Identifier, 5G-S-TMSI) that can uniquely identify the RRC idle mode terminal within a specific area (e.g., tracking area). For reference, the data cell (1k-03) may transmit the message (paging message) received from the CU within the base station of the cell to the terminal (1k-01).

[0345] In the above, the paging terminal identifier may include a short terminal identifier. Alternatively, the paging terminal identifier may be configured with information that can uniquely identify the terminal when combined with the short terminal identifier.

[0346] At step 1k-60, the RRC idle mode or RRC deactivation mode terminal (1k-01) can establish an RRC connection with active data cell 1 (1k-03). For example, when the terminal (1k-01) is in RRC idle mode, the RRC connection can be established by performing an RRC connection establishment procedure with the active data cell 1 (1k-03). When the terminal (1k-01) is in RRC deactivation mode, the RRC connection can be established by performing an RRC connection resume procedure with the active data cell 1 (1k-03).

[0347] A sync cell (1k-02) according to the present disclosure has the characteristic of transmitting a small message indicator to a terminal (1k-01) but not directly transmitting a paging message to the terminal (1k-01). On the other hand, a data cell has the characteristic of not only transmitting a paging message to the terminal (1k-01) but also directly establishing an RRC connection with the terminal (1k-01).

[0348] A terminal (1k-01) according to the present disclosure has a feature that can receive a short message indicator transmitted by a sync cell (1k-02) and transmit a wake-up signal accordingly. Specifically, when the terminal (1k-01) receives the short message indicator transmitted by the sync cell (1k-02), the terminal (1k-01) transmits a wake-up signal to data cells (1k-03, 1k-04, 1k-05) to select an active data cell (1k-03) to determine whether it has been paged, and the paged terminal (1k-01) can establish an RRC connection with the selected active data cell (1k-03).

[0349] FIG. 11 is a flowchart illustrating a process in which a terminal receives a small message indicator from a sync cell and establishes or resumes an RRC connection directly to a data cell in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0350] Referring to FIG. 1l, the terminal (1l-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with active data cell 1 (1l-03) (step 1l-10). At this time, the data cell 1 (1l-03) may be in an active state, and the remaining data cells (1l-04, 1l-05) may be in an inactive state.

[0351] In step 1l-15, active data cell 1 (1l-03) may transmit an RRC connection release message (RRCRelease) to terminal (1l-01) to transition the terminal (1l-01) from RRC connected mode to RRC inactive mode (RRC_INACTIVE) or RRC idle mode (RRC_IDLE). For reference, the active data cell 1 (1l-03) may transmit the message (RRC connection release message) received from a CU in a base station of the cell to the terminal (1l-01). The message may follow at least one of the above-described embodiments. Additionally, the message may include a short terminal identifier.

[0352] In step 11-20, the terminal (11-01) can transition from RRC connected mode (RRC_CONNECTED) to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE). For example, if the terminal (11-01) receives an RRC connection release message containing inactive mode setting information in step 11-15, the terminal (11-01) can apply the message to transition to RRC inactive mode. If the terminal (11-01) receives an RRC connection release message without inactive mode setting information in step 11-15, the terminal (11-01) can apply the message to transition to RRC idle mode.

[0353] In step 1l-23, active data cell 1 (1l-03) may be changed to an inactive state under certain conditions. For example, active data cell 1 (1l-01) may be changed to an inactive state if it does not receive a certain signal (e.g., a wake-up signal (WUS) transmitted by the terminal (1l-01)) from the terminal (1l-01) for a certain period of time after transmitting an RRC connection release message.

[0354] In step 11-25, the RRC inactive mode or RRC idle mode terminal (11-01) can receive a synchronization signal (Sync cell-SSB) transmitted by a Sync cell (11-02). Then, the terminal (11-01) can select or camp on the Sync cell (11-02) (step 11-30). For example, the terminal (11-01) can camp on the Sync cell (11-02) when the Sync cell selection reception signal derived from the received Sync cell-SSB and the signal quality are greater than a predetermined threshold value.

[0355] In step 1l-31, the terminal (1l-01) can receive sync cell system information (Sync cell-SIB) transmitted by the sync cell (1l-02). Then, the terminal (1l-01) can perform a sync cell reselection procedure (step 1l-32).

[0356] According to an embodiment, the Sync cell-SSB (11-25) and the Sync cell-SIB (11-31) may be transmitted periodically. In the present disclosure, at least one of the following information may be included and transmitted through at least one of the Sync cell-SSB and the Sync cell-SIB.

[0357] - Time / frequency resource information for the terminal (1l-01) to transmit a wake-up signal (WUS) (time / frequency resource for WUS)

[0358] - Setting information required to select or reselect a sync cell

[0359] ■ One or more sync cell identifiers

[0360] ■ One or more frequencies on which sync cells operate

[0361] ■ Cell reselection priority by sync cell frequency

[0362] ■ Parameters or threshold values ​​required to select or reselect a sync cell

[0363] - Information about each sync cell and the data cell associated with each sync cell (e.g., data cell identifier, data area code, etc.)

[0364] - Configuration information required to receive DCI containing at least one of a small message indicator, a small message, and paging message scheduling information.

[0365] - Configuration information required to receive paging messages

[0366] In step 11-35, the RRC disabled mode or RRC idle mode terminal (11-01) can monitor paging occasions at specific intervals. The terminal (11-01) can receive a small message indicator through this. The small message indicator can include at least one of the following pieces of information:

[0367] - Indicator indicating whether a paging message exists

[0368] - Shortened UE ID that can identify the above terminal (1l-01)

[0369] - Some terminal identifier values ​​among the paging terminal identifiers used to page the terminal (1l-01) in the paging record stored in the paging message

[0370] Specifically, the terminal (1l-01) can receive the small message indicator by monitoring a paging opportunity and receiving a DCI with a CRC scrambled by a P-RNTI from a Sync cell (1l-02).

[0371] In step 11-37, the RRC inactive mode or RRC idle mode terminal (11-01) can transmit a wake-up signal (WUS). The wake-up signal transmitted by the terminal (11-01) can be a dedicated signal for waking up only a specific inactive data cell, or can be a common signal for waking up all inactive data cells (or all inactive data cells associated with a specific sync cell). All inactive data cells that have received a WUS can become active. Alternatively, among the inactive data cells that have received a WUS, only inactive data cells that meet a predetermined condition (for example, when the WUS reception signal strength is greater than a specific threshold value) can be converted to active data cells. In the present disclosure, for convenience of explanation, inactive data cell 1 (1l-03) may be switched to an active state (1l-38), inactive data cell 2 (1l-04) may be switched to an active state (1l-39), and data cell 3 (1l-04) may continue to remain in an inactive state. The terminal (1l-01) may transmit a WUS to determine whether it has actually been paged by initiating an RRC connection establishment or RRC connection resumption procedure with the data cell.

[0372] Depending on the embodiment, the RRC disabled mode or RRC idle mode terminal (1l-01) may not perform step 1l-37. For example, if the active data cells are transmitting data cell-SSB and / or data-cell SIB, and thus the terminal (1l-01) can select the active data cell, the terminal (1l-01) may not transmit a separate wake-up signal.

[0373] In step 1l-43, active data cell 1 (1l-03) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1l-01). Step 1l-43 may also be performed before step 1l-37.

[0374] In step 1l-44, active data cell 2 (1l-04) may transmit a data cell synchronization signal (data cell-SSB) and / or data cell system information (data cell-SIB). Depending on the embodiment, the data cell-SSB and / or data cell-SIB may be transmitted periodically or upon request of the terminal (1l-01). Step 1l-44 may also be performed before step 1l-37.

[0375] In step 1l-50, an RRC idle mode or RRC deactivation mode terminal (1l-01) can select active data cell 1 (1l-03). The terminal (1l-01) can select the active data cell 1 (1l-03) based on data cell-SSB and / or data cell-SIB transmitted by active data cells (1l-03, 1l-04).

[0376] In step 1l-60, the RRC idle mode or RRC deactivation mode terminal (1l-01) can establish an RRC connection with active data cell 1 (1l-03). For example, when the terminal (1l-01) is in RRC idle mode, the RRC connection can be established by performing an RRC connection establishment procedure with the active data cell 1 (1l-03). When the terminal (1l-01) is in RRC deactivation mode, the RRC connection can be established by performing an RRC connection resume procedure with the active data cell 1 (1l-03).

[0377] In the above, the RRC idle mode or RRC inactive mode terminal (1l-01) can transmit an RRC connection establishment request message or an RRC connection resumption request message to active data cell 1 (1l-03). The message can include information excluding a short terminal identifier among identifier information that can identify the terminal (1l-01). Alternatively, the message can include identifier information that can identify the terminal (1l-01). In response, active data cell 1 (1l-03) can determine whether the terminal (1l-01) is an actual paged terminal, and if it is a paging terminal, can transmit an RRC connection establishment message or an RRC connection resumption message to the terminal (1l-01). If the terminal (1l-01) is not an actual paged terminal, active data cell 1 (1l-03) may transmit an RRC connection rejection message to the terminal (1l-01) in response to receiving an RRC connection establishment request message or an RRC connection resumption request message. The terminal (1l-01) that receives the RRC connection rejection message can thereby confirm that it is not an actual paged terminal.

[0378] A sync cell (1l-02) according to the present disclosure has a characteristic of transmitting only a small message indicator to a terminal (1l-01). A data cell (1l-03) has a characteristic of not transmitting a paging message to the terminal (1l-01) but receiving an RRC connection establishment request message or an RRC connection resumption request message from the terminal (1l-01) to determine whether the terminal (1l-01) is actually a paged terminal. In other words, the data cell (1l-03) has a characteristic of establishing an RRC connection for a paged terminal and not establishing an RRC connection for a non-paged terminal.

[0379] FIG. 1m is a flowchart showing a change in a power state of a data cell in a next-generation mobile communication system that supports network energy saving according to an embodiment of the present invention.

[0380] Referring to FIG. 1m, the terminal (1m-01) may be in RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE) without establishing an RRC connection with the data cell (step 1m-04).

[0381] At step 1m-05, data cells (1m-02, 1m-03) may be in inactive state (inactive mode).

[0382] In step 1m-10, the terminal (1m-01) can transmit a wake-up signal (WUS) to data cells (1m-02, 1m-03). For example, the terminal (1m-01) can be paged and transmit the wake-up signal to wake up an inactive data cell and establish an RRC connection.

[0383] At step 1m-15, data cell 1 (1m-02) may start a predetermined timer and become active. For example, data cell 1 (1m-02) may start a predetermined timer and become active when receiving a WUS transmitted by terminal (1m-01) or when the signal strength of the received WUS is better than a specific threshold value.

[0384] At step 1m-20, data cell 2 (1m-03) may start a predetermined timer and become active. For example, data cell 2 (1m-03) may start a predetermined timer and become active when receiving a WUS transmitted by terminal (1m-01) or when the signal strength of the received WUS is better than a specific threshold value.

[0385] In step 1m-25, active data cell 1 (1m-02) may transmit data cell-SSB and / or data cell-SIB. Additionally, data cell 1 (1m-02) may also transmit a paging message to terminal (1m-01).

[0386] In step 1m-30, active data cell 2 (1m-03) can transmit data cell-SSB and / or data cell-SIB. Additionally, data cell 2 (1m-03) can also transmit a paging message to terminal (1m-01).

[0387] At step 1m-35, the terminal (1m-01) can transition to RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with data cell 1 (1m-02).

[0388] In step 1m-40, data cell 1 (1m-02) may stop (if running) the timer started in step 1m-15. For example, data cell 1 (1m-02) may stop the timer when an RRC connection is established with terminal (1m-01). According to an embodiment, data cell 1 (1m-02) may stop the timer started in step 1m-15 when receiving an additional signal from terminal (1m-01), and start it again, and may stop the timer started when transmitting an RRC connection establishment message (e.g., an RRC connection establishment message or an RRC connection resumption message). Alternatively, data cell 1 (1m-02) may stop the running timer when receiving an RRC connection establishment complete message (e.g., an RRC connection establishment complete message or an RRC connection resumption complete message) from terminal (1m-01).

[0389] At step 1m-45, data cell 2 (1m-03) may have its timer expired at step 1m-20.

[0390] At step 1m-50, data cell 2 (1m-03) can transition to inactive state.

[0391] FIG. 1n is a flowchart illustrating a signaling exchange procedure between a CU and a DU in a next-generation mobile communication system supporting network energy saving according to an embodiment of the present invention.

[0392] Referring to FIG. 1n, a next-generation base station (1n-01, g Node B, hereinafter referred to as gNB, Node B, or base station) may be composed of a CU (1n-02, Central Unit) and one or more DUs (1n-03, 1n-04, Distributed Units). In the present disclosure, for convenience of explanation, it is exemplified that the CU (1n-02) can support two DUs (1n-03, 1n-04). One DU (1n-03, 1n-04) may support only one or more Sync cells (1n-06), or may support one or more data cells (1n-05, 1n-07), or may simultaneously support one or more Sync cells (1n-06) and one or more data cells (1n-05, 1n-07). In this disclosure, for convenience of explanation, it is exemplified that DU 1 (1n-03) supports one data cell (1n-05), and DU 2 (1n-04) supports one Sync cell (1n-06) and one data cell (1n-07).

[0393] At step 1n-10, CU (1n-02) can forward paging messages to DU 1 (1n-03) and DU 2 (1n-04).

[0394] At step 1n-15, DU 2 (1n-04) can forward the paging message received from CU (1n-02) to Sync cell (1n-06) and / or data cell (1n-07).

[0395] At step 1n-20, DU 1 (1n-03) can forward the paging message received from CU (1n-02) to data cell (1n-05).

[0396] At step 1n-25, the sync cell (1n-06) can transmit a paging message to the terminals (1n-07, 1n-08). Depending on the embodiment, the data cell (1n-07) can also transmit a paging message to the terminals (1n-07, 1n-08).

[0397] At step 1n-30, terminal 1 (1n-07) may transmit a wake-up signal (WUS). Depending on the embodiment, terminal 2 (1n-08) may also transmit a WUS.

[0398] At step 1n-35, data cells (1n-05, 1n-07) may be active.

[0399] At step 1n-40, terminal 1 (1n-07) can establish an RRC connection with the base station (1n-01).

[0400] At step 1n-45, terminal 2 (1n-08) can establish an RRC connection with the base station (1n-01).

[0401] In step 1n-50, CU (1n-02) can transmit an indication or information to DU 1 (1n-03) that all terminals included in the paging message in step 1n-10 have been paged and successfully established an RRC connection, and that data cells (1n-05) supported by DU 1 (1n-03) can be powered off and switched to an inactive state. DU 1 (1n-03) can transmit this to data cell (1n-05) (step 1n-55). The data cell (1n-05) can be switched to an inactive state (step 1n-60).

[0402] In the present disclosure, when paged terminal(s) (1n-07, 1n-08) successfully establish an RRC connection with a base station (1n-01), a CU (1n-02) within the base station transmits information or an indication to DUs (1n-03) that they can be powered off, which do not need to communicate with the terminals (1n-07, 1n-08). This is to help the CU (1n-02) within the base station to power off the data cell (1n-05) of the DU (1n-03) that does not need to communicate with the terminals, since the CU (1n-02) within the base station can know which terminals have been paged and whether the corresponding terminals have established an RRC connection. Additionally, the CU (1n-02) within the base station may not provide information that it can be powered off even if there is no terminal connected to the data cell of a specific DU. This is to efficiently support the mobility of a terminal in RRC connection mode even if there is no terminal connected to a specific DU.

[0403] Of course, since the data cells supported by the DU can be powered off based on a timer as in the aforementioned embodiment, the data cells inform the DU of the power status, and the DU also informs the CU of this, so that the DU and the CU can be synchronized with respect to the power status of each data cell.

[0404] Figure 1o is a block diagram showing the internal structure of a terminal according to one embodiment of the present invention.

[0405] Referring to FIG. 1o, the terminal may include an RF (Radio Frequency) processing unit (1o-10), a baseband processing unit (1o-20), a storage unit (1o-30), and a control unit (1o-40).

[0406] The RF processing unit (1o-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1o-10) up-converts the baseband signal provided from the baseband processing unit (1o-20) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (1o-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In Fig. 1o, only one antenna is illustrated, but the terminal may be equipped with multiple antennas. In addition, the RF processing unit (1o-10) may include multiple RF chains. Furthermore, the RF processing unit (1o-10) may perform beamforming. For the above beamforming, the RF processing unit (1o-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. In addition, the RF processing unit (1o-10) can perform MIMO and can receive multiple layers when performing the MIMO operation.

[0407] The baseband processing unit (1o-20) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (1o-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (1o-20) restores the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (1o-10). For example, in the case of OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (1o-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing an inverse fast Fourier transform (IFFT) operation and inserting a cyclic prefix (CP). In addition, when receiving data, the baseband processing unit (1o-20) divides the baseband signal provided from the RF processing unit (1o-10) into OFDM symbol units, restores signals mapped to subcarriers through FFT (fast Fourier transform), and then restores the received bit string through demodulation and decoding.

[0408] The baseband processing unit (1o-20) and the RF processing unit (1o-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (1o-20) and the RF processing unit (1o-10) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (1o-20) and the RF processing unit (1o-10) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (1o-20) and the RF processing unit (1o-10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), etc. Additionally, the different frequency bands may include a super high frequency (SHF) (e.g., 2.NRHz, NRhz) band and a millimeter wave (mm wave) (e.g., 60GHz) band.

[0409] The above storage unit (1o-30) stores data such as basic programs, application programs, and setting information for the operation of the terminal. In addition, the storage unit (1o-30) provides the stored data at the request of the control unit (1o-40).

[0410] The control unit (1o-40) controls the overall operations of the terminal. For example, the control unit (1o-40) transmits and receives signals through the baseband processing unit (1o-20) and the RF processing unit (1o-10). In addition, the control unit (1o-40) records and reads data in the storage unit (1o-40). For this purpose, the control unit (1o-40) may include at least one processor. For example, the control unit (1o-40) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0411] FIG. 1p is a block diagram showing the configuration of an NR base station according to an embodiment of the present invention.

[0412] Referring to FIG. 1p, the base station may be configured to include an RF processing unit (1p-10), a baseband processing unit (1p-20), a backhaul communication unit (1p-30), a storage unit (1p-40), and a control unit (1p-50).

[0413] The RF processing unit (1p-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1p-10) up-converts the baseband signal provided from the baseband processing unit (1p-20) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (1p-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In Fig. 1p, only one antenna is illustrated, but the base station may be equipped with multiple antennas. In addition, the RF processing unit (1p-10) may include multiple RF chains. Furthermore, the RF processing unit (1p-10) may perform beamforming. For the above beamforming, the RF processing unit (1p-10) can adjust the phase and magnitude of each signal transmitted and received through multiple antennas or antenna elements. The RF processing unit (1p-10) can perform a downlink MIMO operation by transmitting one or more layers.

[0414] The baseband processing unit (1p-20) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the wireless access technology. For example, when transmitting data, the baseband processing unit (1p-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (1p-20) restores the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (1p-10). For example, in the case of OFDM, when transmitting data, the baseband processing unit (1p-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (1p-20) divides the baseband signal provided from the RF processing unit (1p-10) into OFDM symbol units, restores signals mapped to subcarriers through FFT operation, and then restores the received bit string through demodulation and decoding. The baseband processing unit (1p-20) and the RF processing unit (1p-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (1p-20) and the RF processing unit (1p-10) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0415] The above backhaul communication unit (1p-30) provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit (1p-30) converts a bit stream transmitted from the base station to another node, such as another base station (e.g., an auxiliary base station), a core network, etc., into a physical signal, and converts a physical signal received from the other node into a bit stream.

[0416] The storage unit (1p-40) stores data such as basic programs, application programs, and configuration information for the operation of the base station. In particular, the storage unit (1p-40) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. In addition, the storage unit (1p-40) can store information that serves as a judgment criterion for whether to provide or terminate multiple connections to a terminal. In addition, the storage unit (1p-40) provides the stored data at the request of the control unit (1p-50).

[0417] The control unit (1p-50) controls the overall operations of the base station. For example, the control unit (1p-50) transmits and receives signals through the baseband processing unit (1p-20) and the RF processing unit (1p-10) or through the backhaul communication unit (1p-30). In addition, the control unit (1p-50) records and reads data in the storage unit (1p-40). For this purpose, the control unit (1p-50) may include at least one processor.

[0418] It should be noted that the configuration diagrams, exemplary diagrams of control / data signal transmission methods, exemplary diagrams of operating procedures, and configuration diagrams illustrated in the above FIGS. 1A to 1P are not intended to limit the scope of the present disclosure. That is, not all components, entities, or operational steps described in the above FIGS. 1A to 1P should be construed as essential components for carrying out the disclosure, and the disclosure may be implemented without detriment to the essence of the disclosure even if only some components are included.

[0419] The operations of the network entity or terminal described above can be realized by providing a memory device storing the corresponding program code within any component of the network entity or terminal device. That is, the control unit of the network entity or terminal device can execute the operations described above by reading and executing the program code stored in the memory device using a processor or CPU (Central Processing Unit).

[0420] The various components and modules of the network entity, base station or terminal device described in this specification may be operated using hardware circuits, such as logic circuits based on complementary metal oxide semiconductors, firmware, software and / or hardware and firmware and / or software embedded in a machine-readable medium. For example, various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates and application-specific semiconductors.

[0421] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. A method performed by a terminal of a wireless communication system, A step of receiving information related to transmission of a paging message from a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state; A step of receiving the paging message including information indicating the terminal based on information associated with transmission of the paging message; Step of selecting a data cell; and A method comprising the step of performing an RRC connection procedure with the data cell based on the paging message.

2. In the first paragraph, the step of selecting the data cell comprises: A step of transmitting a wake up signal to at least one data cell if there is no suitable data cell; A step of receiving at least one of a synchronization signal or system information from at least one data cell; and A method characterized by comprising the step of selecting the data cell from among the at least one data cell based on at least one of the synchronization signal or the system information.

3. In paragraph 1, A method, characterized in that the paging message is transmitted from either the synchronous cell or the data cell.

4. In paragraph 1, A method characterized by further comprising the step of transmitting a wake up signal to at least one data cell prior to reception of the paging message, based on reception of information associated with transmission of the paging message.

5. A method performed by a base station of a wireless communication system, A step of transmitting information related to transmission of a paging message to the terminal through a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state; A step of transmitting the paging message including information indicating the terminal to the terminal based on information associated with transmission of the paging message; and A method comprising the step of receiving a message from the terminal requesting an RRC connection to a data cell selected by the terminal based on the paging message.

6. In paragraph 5, If there is no suitable data cell, a step of receiving a wake up signal transmitted to at least one data cell from the terminal; and Further comprising the step of transmitting at least one of a synchronization signal or system information to the terminal with at least one data cell, A method, characterized in that said data cell is selected from said at least one data cell based on at least one of said synchronization signal or said system information.

7. In paragraph 5, A method, characterized in that the paging message is transmitted from either the synchronous cell or the data cell.

8. In paragraph 5, A method characterized by further comprising the step of receiving, from the terminal, a wake up signal transmitted to at least one data cell prior to transmission of the paging message, based on transmission of information associated with transmission of the paging message.

9. In the terminal of a wireless communication system, Transmitter and receiver; and A terminal including a control unit that receives, through the transceiver, information associated with transmission of a paging message from a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state, and receives, through the transceiver, a paging message including information indicating the terminal based on the information associated with transmission of the paging message, and selects a data cell and, based on the paging message, performs an RRC connection procedure with the data cell.

10. In the 9th paragraph, the control unit, A terminal characterized in that, when there is no suitable data cell, a wake up signal is transmitted to at least one data cell through the transceiver, at least one of a synchronization signal or system information is received from the at least one data cell through the transceiver, and the data cell is selected from among the at least one data cell based on at least one of the synchronization signal or the system information.

11. In paragraph 9, A terminal, characterized in that the paging message is transmitted from either the synchronous cell or the data cell.

12. In paragraph 9, the control unit, A terminal characterized in that, based on the reception of information associated with the transmission of the paging message, a wake up signal is transmitted to at least one data cell through the transceiver prior to the reception of the paging message.

13. In a base station of a wireless communication system, Transmitter and receiver; and A base station including a control unit that transmits, to the terminal through the transceiver, information associated with transmission of a paging message to a synchronization cell when the terminal is in an RRC (radio resource control) inactive state or an RRC idle state, transmits, to the terminal through the transceiver, a paging message including information indicating the terminal based on the information associated with transmission of the paging message, and receives, from the terminal through the transceiver, a message requesting an RRC connection to a data cell selected by the terminal based on the paging message.

14. In the 13th paragraph, the control unit, If there is no appropriate data cell, a wake up signal transmitted to at least one data cell is received from the terminal through the transceiver, and at least one of a synchronization signal or system information is transmitted to the terminal through the transceiver with the at least one data cell. The data cell is selected from among the at least one data cell based on at least one of the synchronization signal or the system information, A base station, characterized in that the paging message is transmitted from either the synchronous cell or the data cell.

15. In the 13th paragraph, the control unit, A base station characterized in that, based on transmission of information associated with transmission of the paging message, a wake up signal transmitted to at least one data cell before transmission of the paging message is received from the terminal through the transceiver.

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