Method and apparatus for performing discontinuous reception in a wireless communication system

Abstract

The present disclosure relates to a fifth generation (5G) or pre-5G communication system for supporting a higher data transmission rate than a fourth generation (4G) communication system (such as long term evolution (LTE)). The present disclosure provides a method and apparatus for performing DRX in a wireless communication system. A method for operating a terminal in a wireless communication system includes: detecting a wake-up signal (WUS), and determining whether to detect a physical downlink control channel (PDCCH) or a paging message in a specific time period based on the WUS.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication systems, and more particularly, to an apparatus and method for performing discontinuous reception (DRX) in a wireless communication system. Background Art

[0002] In order to meet the growing demand for wireless data traffic after the commercialization of the fourth generation (4G) communication system, efforts have been made to develop advanced fifth generation (5G) communication systems or pre-5G communication systems. Therefore, 5G communication systems or pre-5G communication systems are called super 4G network communication systems or post-long term evolution (LTE) systems.

[0003] In order to achieve high data rates, 5G communication systems are considering their implementation in extremely high frequency (millimeter wave (mmWave)) bands (e.g., 60 GHz bands). In order to mitigate the path loss of radio waves and extend the propagation distance of radio waves in extremely high frequency bands, 5G communication systems are discussing beamforming, massive multiple input multiple output (MIMO), full dimensional (FD)-MIMO, array antennas, analog beamforming, and massive antenna technology.

[0004] In addition, for network enhancement of the system, 5G communication systems are developing such as evolved small cells, advanced small cells, cloud radio access network (RAN), ultra-dense networks, device to device (D2D) communication, wireless backhaul, mobile networks, collaborative communications, coordinated multi-points (CoMP) and receive interference cancellation.

[0005] In addition, 5G systems are studying hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superlocation coding (SWSC) as advanced coding modulation (ACM) schemes, as well as filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies. Summary of the invention

[0006] Technical issues

[0007] Based on the above discussion, the present disclosure provides an apparatus and method for efficiently performing discontinuous reception (DRX) in a wireless communication system.

[0008] Solution to the problem

[0009] According to various embodiments of the present disclosure, an operation method of a user equipment (UE) in a wireless communication system includes: detecting a wake-up signal (WUS), and determining whether to detect a physical downlink control channel (PDCCH) or a paging message at a specific time based on the WUS.

[0010] According to various embodiments of the present disclosure, a device of a UE in a wireless communication system includes: a transceiver; and at least one processor, wherein the at least one processor is configured to detect a WUS and determine whether to detect a PDCCH or a paging message at a specific time based on the WUS.

[0011] Advantageous Effects of the Invention

[0012] According to the apparatus and method of various embodiments of the present disclosure, it is possible to effectively perform discontinuous reception (DRX) in a wireless communication system.

[0013] Effects obtainable from the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood from the following description by those skilled in the art of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1An example of a wireless communication system according to various embodiments of the present disclosure is shown.

[0015] Figure 2 An example of a radio protocol architecture of a wireless communication system according to various embodiments of the present disclosure is shown.

[0016] Figure 3 An example of a structure of a wireless communication system according to various embodiments of the present disclosure is shown.

[0017] Figure 4 An example of a radio protocol architecture of a wireless communication system according to various embodiments of the present disclosure is shown.

[0018] Figure 5 is a block diagram illustrating a configuration of a user equipment (UE) according to various embodiments of the present disclosure.

[0019] Figure 6 is a block diagram illustrating a configuration of an evolved node B (eNB) according to various embodiments of the present disclosure.

[0020] Figure 7 A discrete reception (DRX) operation according to various embodiments of the present disclosure is illustrated.

[0021] Figure 8 A process of transmitting and receiving a wake-up signal (WUS) according to various embodiments of the present disclosure is illustrated.

[0022] Fig. 9 is a flowchart of a process for receiving a WUS at a UE according to various embodiments of the present disclosure.

[0023] Fig.10 is a flowchart of a process of a UE for performing first UE operations according to various embodiments of the present disclosure.

[0024] Fig.11 is a flowchart of a process of a UE for performing second UE operations according to various embodiments of the present disclosure.

[0025] Fig.12 A process of a UE for transmitting and receiving a WUS signal in an idle mode according to various embodiments of the present disclosure is illustrated.

[0026] Fig.13 A process of a UE for sending and receiving a WUS signal in a connected mode according to various embodiments of the present disclosure is illustrated.

[0027] Fig.14 is a flowchart of a process for a UE to receive a WUS signal in an idle mode according to various embodiments of the present disclosure.

[0028] Fig.15 is a flowchart of a process for a UE to receive a WUS signal in a connected mode according to various embodiments of the present disclosure.

[0029] Fig.16 An RRC inactive mode / state or an RRC light connected mode according to various embodiments of the present disclosure is shown.

[0030] Fig.17 An example of a process of establishing a connection with a network for a UE to transmit and receive data in a wireless communication system according to various embodiments of the present disclosure is shown.

[0031] Fig.18 1 is a signal flow diagram between a UE and a gNB for supporting an RRC inactive mode / state in a wireless communication system according to various embodiments of the present disclosure.

[0032] Fig.19 An example of paging area configuration of an RRC inactive mode / state UE in a wireless communication system according to various embodiments of the present disclosure is shown.

[0033] Fig. 20 An example of operation of an RRC inactive mode / state UE according to various embodiments of the present disclosure is shown.

[0034] Fig.21 An example of operation of an RRC inactive mode / state UE according to various embodiments of the present disclosure is shown.

[0035] Fig. 22 An example of operation of an RRC inactive mode / state UE according to various embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0036] The terms used in the present disclosure are used to describe specific embodiments and are not intended to limit the scope of other embodiments. Unless explicitly stated otherwise, the singular may include the plural. All terms used herein, including technical and scientific terms, may have the same meaning as the terms generally understood by those skilled in the art to which the present disclosure belongs. Among the terms used in the present disclosure, the terms defined in the general dictionary may be interpreted as having the same or similar meaning as the context of the relevant technology, and unless clearly defined in the present disclosure, it should not be ideally or excessively interpreted as a formal meaning. In some cases, even the terms defined in the present disclosure should not be interpreted as excluding embodiments of the present disclosure.

[0037] Hereinafter, the present disclosure relates to an apparatus and method for sending a wake-up signal (WUS) in a wireless communication system. Terms indicating a communication scheme, terms indicating a signal, terms indicating information, terms indicating a network entity, and terms indicating components of a device used in the following description are for the purpose of explanation. Therefore, the present disclosure is not limited to the terms to be described, and other terms having the same technical meaning may be used.

[0038] In addition, the present disclosure uses the terms used in some communication standards (e.g., the 3rd generation partnership project (3GPP)) to describe various embodiments, which is only an exemplary explanation. The various embodiments of the present disclosure can be easily modified and can also be applied to other communication systems.

[0039] Figure 1 An example of a wireless communication system according to various embodiments of the present disclosure is shown. Specifically, Figure 1 The structure of the LTE system is shown.

[0040] refer to Figure 1 , the radio access network of the LTE system shown includes evolved Node Bs, eNBs, Node Bs or base stations 105, 110, 115 and 120, and a mobility management entity (MME) 125 and a serving-gateway (S-GW) 130. User equipment (UE) or terminal 135 accesses external networks via the eNBs 105, 110, 115 and 120 and the S-GW 130.

[0041] exist Figure 1In the LTE system, eNBs 105, 110, 115, and 120 correspond to existing node Bs of the universal mobile telecommunications system (UMTS) system. The eNB 105 is connected to the UE 135 through a radio channel and performs a more complex role than the existing node B. Since each user traffic including real-time services such as voice over internet protocol (VoIP) is served through a shared channel in the LTE system, the equipment for collecting and scheduling status information such as buffer status, available transmission power status, and channel status is managed by eNBs 105, 110, 115, and 120. One eNB typically controls multiple cells. For example, in order to achieve a transmission rate of 100 Mbps, the LTE system uses orthogonal frequency division multiplexing (OFDM) as a radio access technology, for example, in a 20 MHz bandwidth. In addition, the LTE system applies an adaptive modulation & coding (AMC) scheme that determines the modulation scheme and channel coding rate according to the channel state of the UE. The S-GW 130 is a device for providing a data bearer, and generates or removes a data bearer under the control of the MME 125. The MME is a device that manages various control functions and a mobility management function for a UE, and is connected to a plurality of eNBs.

[0042] Figure 2 An example of a radio protocol architecture of a wireless communication system according to various embodiments of the present disclosure is shown. Specifically, Figure 2 The radio protocol architecture in the LTE system is shown.

[0043] refer to Figure 2 The radio protocol of the LTE system includes the packet data convergence protocol (PDCP) layer 205 and 240, the radio link control (RLC) layer 210 and 235, the medium access control (MAC) layer 215 and 230, and the physical (PHY) layer 220 and 225 in the UE and eNB, respectively.

[0044] The PDCP layers 205 and 240 manage operations such as IP header compression / recovery. The main functions of PDCP are summarized as follows.

[0045] -Header compression and decompression (ROHC only)

[0046] -Transmission of user data

[0047] - In-sequence delivery of upper layer PDUs during PDCP reestablishment for RCL AM

[0048] - For split bearers in DC (supports RLC AM only): PDCP PDU routing for transmission and PDCP PDU reordering for reception

[0049] -Duplication detection of lower layer SDUs during PDCP reestablishment of RLC AM

[0050] - For RLC AM, retransmit PDCP SDUs at handover, and for split bearers in DC, retransmit PDCP PDUs during PDCP data recovery

[0051] -Encryption and decryption

[0052] - Timer-based SDU discard in uplink

[0053] The RLC layers 210 and 235 perform an automatic repeat request (ARQ) operation by reconfiguring a PDCP packet data unit (PDU) with an appropriate size. The main functions of the RLC are summarized as follows.

[0054] -Transmission of upper layer PDU

[0055] - Error correction via ARQ (for AM data transmission only)

[0056] -RLC SDU concatenation, segmentation and reassembly (only for UM and AM data transmission)

[0057] - Re-segmentation of RLC data PDU (only for AM data transmission)

[0058] - Reordering of RLC data PDUs (only for UM and AM data transmission)

[0059] - Duplicate detection (for UM and AM data transmission only)

[0060] -Protocol error detection (for AM data transmission only)

[0061] -RLC SDU discard (only for UM and AM data transmission)

[0062] -RLC reconstruction

[0063] The MAC layers 215 and 230 are connected to a plurality of RLC layer devices configured in one UE, and perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs out of MAC PDUs. The main functions of MAC are summarized as follows.

[0064] - Mapping between logical channels and transport channels

[0065] - MAC SDUs belonging to one or different logical channels are multiplexed into or demultiplexed from transport blocks (TBs), and transport blocks (TBs) are delivered to the physical layer on transport channels or delivered from the physical layer on transport channels

[0066] -Dispatch information report

[0067] -HARQ function (error correction through HARQ)

[0068] - Priority handling between logical channels of a UE

[0069] - Priority handling between UEs through dynamic scheduling

[0070] -MBMS service logo

[0071] -Transmission format selection

[0072] -filling

[0073] The PHY layers 220 and 225 channel-code and modulate higher layer data, and generate and transmit OFDM symbols to a radio channel, or demodulate and channel-decode OFDM symbols received through a radio channel and transmit the demodulated and channel-decoded data to a higher layer.

[0074] Figure 3 An example of a wireless communication system according to various embodiments of the present disclosure is shown. Specifically, Figure 3 The structure of the new radio (NR) proposed in the present disclosure is shown.

[0075] refer to Figure 3 , the radio access network of NR includes a new radio node B (gNB) 310 and a new radio core network (AMF) 305. The NR UE or terminal 315 accesses the external network via the gNB 310 and the AMF 305.

[0076] The gNB 310 corresponds to the eNB of the existing LTE system. The gNB 310 is connected to the NR UE through a wireless channel and can provide better services than the existing eNB 320. Since each user traffic is served through a shared channel in NR, the equipment for collecting and scheduling state information (such as the buffer status of the UE, the available transmission power status, and the channel status) is managed by the gNB 310. One gNB 310 usually controls multiple cells. Compared with the existing LTE, NR may have a bandwidth exceeding the existing maximum bandwidth to achieve high-speed data transmission, and adopts beamforming technology other than OFDM as a radio access technology. In addition, NR applies an adaptive modulation and coding (AMC) scheme that determines the modulation scheme and channel coding rate according to the channel state of the UE. AMF 305 performs functions such as mobility support, bearer establishment, and QoS (quality of service, QoS) establishment. AMF is a device that manages various control functions and mobility management functions for the UE and is connected to multiple gNBs. In addition, NR can interoperate with the existing LTE system, and AMF is connected to MME 325 through a network interface. The MME 325 is connected to the eNB 330 which is an existing eNB. The UE 315 supporting LTE-NR dual connectivity can send and receive data 335 while maintaining connections with the eNB 330 and the gNB 310.

[0077] Figure 4 An example of a radio protocol architecture of a wireless communication system according to various embodiments of the present disclosure is shown. Specifically, Figure 4 The radio protocol structure of NR proposed in this disclosure is shown.

[0078] refer to Figure 4 , the radio protocol of NR includes the NR PDCP layer 405 and 440, the NR RLC layer 410 and 435, the NR MAC layer 415 and 430, and the NR PHY layer 420 in the UE and NR gNB, respectively.

[0079] The main functions of the NR PDCP layers 405 and 440 may include some of the following functions.

[0080] Header compression and decompression (ROHC only)

[0081] -Transmission of user data

[0082] - In-sequence delivery of upper layer PDUs

[0083] - Reordering of received PDCP PDUs

[0084] - Duplicate detection of lower layer SDU

[0085] -Retransmission of PDCP SDU

[0086] -Encryption and decryption

[0087] - Timer-based SDU discard in uplink

[0088] The reordering function of the NR PDCP device indicates a function of reordering the PDCP PDU received from the lower layer based on the PDCP sequence number (SN), which may include a function for delivering data to the upper layer in sequence, a function for reordering and recording lost PDCP PDUs, a function for sending a status report of lost PDCP PDUs to the transmitting side, and a function for requesting retransmission of lost PDCP PDUs.

[0089] The main functions of the NR RLC layers 410 and 435 may include some of the following functions.

[0090] -Transmission of upper layer PDU

[0091] - In-sequence delivery of upper layer PDUs

[0092] - Out-of-order delivery of upper layer PDUs

[0093] - Error correction via ARQ

[0094] - Concatenation, segmentation and reassembly of RLC SDU

[0095] - Re-segmentation of RLC data PDUs

[0096] - Reordering of RLC data PDUs

[0097] - Duplicate detection

[0098] -Protocol error detection

[0099] -RLC SDU discard function

[0100] -RLC reconstruction

[0101] If one RLC SDU is segmented and received in multiple RLC SDUs, the in-sequence delivery indication of the NR RLC device may include the function of delivering the RLC PDUs received from the lower layer to the upper layer in sequence, which may include the function of reassembling and delivering them, which may include the function of reordering the received RLC PDUs based on the RLC SN or PDCP SN, which may include the function of reordering and recording the lost PDCP PDUs, which may include the function of reporting the status of the lost RLC PDUs to the transmitting side, which may include the function of requesting retransmission of the lost RLC PDUs, and if there are lost RLC SDUs, which may include the function of delivering only the RLC PDU to the upper layer in sequence before the lost RLC SDUs, or may include the following function: despite the existence of lost RLC SDUs, if a specific timer expires, all received RLC SDUs are delivered to the upper layer in sequence before the timer starts, or may include the following function: despite the existence of lost RLC SDUs, if a specific timer expires, all currently received RLC SDUs are delivered to the upper layer in sequence. If one RLC SDU is segmented and received in multiple RLC SDUs, the out-of-order delivery indication of the NR RLC device directly delivers the RLC PDU received from the lower layer to the upper layer without considering the order, which may include the function of reassembling and delivering them, and may include the function of storing the RLC SN or PDCP SN of the received RLC PDU, sorting them, and recording the lost RLC PDU.

[0102] The NR MAC layers 415 and 430 can be connected to multiple NR RLC layer devices configured in one UE, and the main functions of the NR MAC may include some of the following functions.

[0103] - Mapping between logical channels and transport channels

[0104] -Multiplexing / demultiplexing of MAC SDU

[0105] -Dispatch information report

[0106] -HARQ function (error correction through HARQ)

[0107] - Priority handling between logical channels of a UE

[0108] - Priority handling between UEs through dynamic scheduling

[0109] -MBMS service logo

[0110] -Transmission format selection

[0111] -filling

[0112] The NR physical layers 420 and 425 may perform the following operations: channel coding and modulating upper layer data, generating and sending OFDM symbols through a wireless channel, or demodulating and channel decoding OFDM symbols received through a wireless channel and delivering the demodulated and channel-decoded data to an upper layer.

[0113] Although in Figure 4 Although not shown in the figure, the radio resource control (RRC) layer exists above the PDCP layer of the UE and the gNB, and the RRC layer can exchange configuration control messages of radio resource control related to connection and measurement.

[0114] Figure 5 is a block diagram illustrating a configuration of a UE according to various embodiments of the present disclosure.

[0115] refer to Figure 5 , the UE includes a radio frequency (RF) processing unit 510, a baseband processing unit 520, a storage unit 530 and a control unit 540.

[0116] The RF processing unit 510 may perform functions for transmitting and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processing unit 510 may up-convert the baseband signal provided from the baseband processing unit 520 into an RF band signal, and then transmit it via an antenna, and down-convert the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 510 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and the like. Although in Figure 5 Only one antenna is shown in the figure, but the UE may include multiple antennas. In addition, the RF processing unit 510 may include multiple RF chains. In addition, the RF processing unit 510 may perform beamforming. For beamforming, the RF processing unit 510 may adjust the phase and size of the signal sent or received through multiple antennas or antenna elements. In addition, the RF processing unit may perform multiple-input multiple-output (MIMO) and receive multiple layers during MIMO operation.

[0117] The baseband processing unit 520 performs a conversion function between a baseband signal and a bit string according to the physical layer standard of the system. For example, in data transmission, the baseband processing unit 520 generates a complex symbol by encoding and modulating the transmission bit string. In addition, in data reception, the baseband processing unit 520 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processing unit 510. For example, according to the OFDM scheme, in data transmission, the baseband processing unit 520 generates a complex symbol by encoding and modulating the transmission bit string, maps the complex symbol to a subcarrier, and then generates an OFDM symbol by an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, in data reception, the baseband processing unit 520 divides the baseband signal provided from the RF processing unit 510 into OFDM symbol units, recovers the signal mapped to the subcarrier by an FFT operation, and recovers the received bit string by demodulation and decoding.

[0118] The baseband processing unit 520 and the RF processing unit 510 send and receive signals as described above. Therefore, the baseband processing unit 520 and the RF processing unit 510 can be referred to as a sending unit, a receiving unit, a sending and receiving unit, a transceiver or a communication unit. In addition, at least one of the baseband processing unit 520 and the RF processing unit 510 may include a plurality of communication modules to support a variety of different radio access technologies. In addition, at least one of the baseband processing unit 520 and the RF processing unit 510 may include different communication modules for processing signals of different frequency bands. For example, different radio access technologies may include wireless LAN (e.g., Institute of Electrical and Electronics Engineers (Institute of Electrical and Electronics Engineers, IEEE) 802.11), cellular networks (e.g., LTE), etc. In addition, different frequency bands may include super high frequency (SHF) (e.g., 2.NRhz, NRHz) bands and millimeter wave (e.g., 60GHz) bands.

[0119] The storage unit 530 stores data such as basic programs, applications, and setting information for the operation of the UE. In particular, the storage unit 530 may store information related to a second access node that performs wireless communication using a second radio access technology. The storage unit 530 provides the stored data according to a request of the control unit 540.

[0120] The control unit 540 controls the overall operation of the UE. For example, the control unit 540 sends and receives signals through the baseband processing unit 520 and the RF processing unit 510. In addition, the control unit 540 records data in the storage unit 530 and reads data from the storage unit 530. To this end, the control unit 540 may include at least one processor. For example, the control unit 540 may include a communication processor (CP) for controlling communication and an application processor (AP) for controlling a higher layer such as an application. In addition, the control unit 540 may include a multi-connection processor 542.

[0121] Figure 6 is a block diagram illustrating a configuration of an eNB according to various embodiments of the present disclosure.

[0122] refer to Figure 6 , the eNB includes an RF processing unit 610, a baseband processing unit 620, a backhaul communication unit 630, a storage unit 640 and a control unit 650.

[0123] The RF processing unit 610 may perform functions for transmitting and receiving signals through a radio channel, such as signal band conversion and amplification. That is, the RF processing unit 610 up-converts the baseband signal provided from the baseband processing unit 620 into an RF band signal, and then transmits it via an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit 610 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. Although in Figure 6 Only one antenna is shown in FIG. 6 , but the first access node may include multiple antennas. In addition, the RF processing unit 610 may include multiple RF chains. In addition, the RF processing unit 610 may perform beamforming. For beamforming, the RF processing unit 610 may adjust the phase and size of the signal sent or received through multiple antennas or antenna elements. The RF processing unit may perform downlink MIMO operations by sending one or more layers.

[0124] The baseband processing unit 620 performs a conversion function between a baseband signal and a bit string according to the physical layer standard of the first radio access technology. For example, in data transmission, the baseband processing unit 620 generates a complex symbol by encoding and modulating the transmission bit string. In addition, in data reception, the baseband processing unit 620 recovers the received bit string by demodulating and decoding the baseband signal provided from the RF processing unit 610. For example, according to the OFDM scheme, in data transmission, the baseband processing unit 620 generates a complex symbol by encoding and modulating the transmission bit string, maps the complex symbol to a subcarrier, and then generates an OFDM symbol by an IFFT operation and CP insertion. In addition, in data reception, the baseband processing unit 620 divides the baseband signal provided from the RF processing unit 610 into OFDM symbol units, recovers the signal mapped to the subcarrier by an FFT operation, and recovers the received bit string by demodulation and decoding. The baseband processing unit 620 and the RF processing unit 610 send and receive signals as described above. Therefore, the baseband processing unit 620 and the RF processing unit 610 may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, a transceiver, or a communication unit.

[0125] The backhaul communication unit 630 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 630 converts a bit string sent from the master base station to another node (eg, an auxiliary base station or a core network) into a physical signal, and converts a physical signal received from another node into a bit string.

[0126] The storage unit 640 stores data such as basic programs, applications, and setting information for the operation of the master base station. In particular, the storage unit 640 may store information related to the bearer assigned to the connected UE, the measurement result reported from the connected UE, etc. In addition, the storage unit 640 may store information that becomes the basis for determining whether to provide or suspend multiple connections to the UE. The storage unit 640 provides the stored data according to the request of the control unit 650.

[0127] The control unit 650 controls the overall operation of the master base station. For example, the control unit 650 sends and receives signals through the baseband processing unit 620 and the RF processing unit 610 or the backhaul communication unit 630. In addition, the control unit 650 records data in the memory 640 and reads data from the memory 640. To this end, the control unit 650 may include at least one processor. For example, the control unit 650 may include a CP for controlling communication and an AP for controlling an upper layer such as an application. In addition, the control unit 650 may include a multi-connection processor 652.

[0128] Figure 7 A discrete reception (DRX) operation according to various embodiments of the present disclosure is illustrated.

[0129] DRX is applied to minimize the power consumption of the UE, and is a technology that monitors only a preset PDCCH to obtain scheduling information. DRX can operate in both idle mode and connected mode, and its operation method is slightly different.

[0130] The present disclosure relates to connected mode. In order for the UE to obtain scheduling information, continuous monitoring of the PDCCH will result in considerable power consumption. The basic DRX operation has a DRX cycle 700, and the PDCCH is only monitored for the on-Duration 705. The DRX cycle in connected mode is set to two values, long DRX and short DRX. In general, the long DRX cycle is applied, and if necessary, the eNB can use the MAC control element (CE) to trigger the short DRX cycle. After a certain time, the UE changes from the short DRX cycle to the long DRX cycle. The initial scheduling information for a specific UE is only provided in the preset PDCCH. Therefore, the UE can minimize power consumption by only periodically monitoring the PDCCH.

[0131] For the on duration 705, if the PDCCH 710 receives scheduling information for a new packet, the UE starts a DRX inactivity timer (IAT) 715. The UE remains active during the DRX IAT. That is, the UE continuously monitors the PDCCH during the DRX IAT. In addition, the UE also starts a HARQ RTT timer 720. The HARQ RTT timer is used to prevent the UE from unnecessarily monitoring the PDCCH during the HARQ round trip time (RTT). The UE does not need to perform PDCCH monitoring within the time of the HARQ RTT timer 720. However, when the DRX IAT and HARQ RTT timers operate simultaneously, the UE continues PDCCH monitoring based on the DRX IAT. If the HARQ RTT timer expires, the DRX retransmission (RTX) timer starts 725. When the DRX RTX timer operates, the UE must perform PDCCH monitoring. Generally, during the operating time of the DRX RTX timer, scheduling information 730 for HARQ retransmissions is received. If scheduling information for HARQ retransmission is received, the UE immediately stops the DRX RTX timer and restarts the HARQ RTT timer. The operation continues until a packet 735 is successfully received.

[0132] Configuration information related to DRX operation in connected mode is delivered to the UE via the RRCConnectionReconfiguration message. The on-duration timer, DRX IAT and DRX RTX timer are defined by the number of PDCCH subframes. After the timer is started, if the set number of subframes defined as PDCCH subframes has passed, the timer expires. All downlink subframes belong to PDCCH subframes in FDD, and downlink subframes and special subframes correspond to PDCCH subframes in TDD. In TDD, downlink subframes, uplink subframes and special subframes exist in the same frequency band. Among them, downlink subframes and special subframes are regarded as PDCCH subframes.

[0133] The eNB can set two states: long DRX and short DRX. The eNB usually uses one of the two states by considering the power preference indication information reported from the UE, the UE mobility record information and the characteristics of the configured data radio bearer (DRB). The two states are converted according to whether a specific timer expires or by sending a specific MAC CE to the UE.

[0134] Figure 8 A process of transmitting and receiving a wake-up signal (WUS) according to various embodiments of the present disclosure is illustrated.

[0135] DRX operation helps to reduce the power consumption of UE. In addition, in order to further reduce the power consumption of UE, WUS has been proposed. The key to DRX operation is to identify whether a new schedule has occurred only in the on-duration 805 at the DRX cycle 810 set. Therefore, in order to identify the presence or absence of scheduling, it is not necessary to monitor PDCCH at every opportunity, and power consumption can be reduced at the opportunity without monitoring. However, since PDCCH is monitored for each on-duration, the power of UE is still consumed at the corresponding opportunity. In order to reduce the power consumption of the corresponding opportunity, WUS 815 can be sent in a very short opportunity before the on-duration arrives. WUS 815 indicates whether the UE needs to wake up (wake up) during the on-duration and receive a signal from the eNB. If a downlink (DL) allocation, uplink (UL) permission or paging message for the UE is transmitted during the upcoming on-duration, the eNB sends WUS in a specific short opportunity before the on-duration. If the UE receives WUS at a short opportunity and the WUS indicates receiving a signal from the eNB, the UE needs to wake up during the upcoming on-duration and receive a signal from the eNB. Otherwise, if the UE does not receive a WUS in a short period of time, or the received WUS indicates that no signal is received from the eNB, the UE does not need to wake up during the on-duration. Therefore, the UE can pre-identify whether to wake up during the on-duration through the WUS operation and minimize the power consumed during the on-duration.

[0136] In the present disclosure, the operation of the UE has been described based on the connected mode DRX (C-DRX) operation in the connected mode, but the operation of the UE can also be applied to the paging cycle operation in the idle mode. That is, the eNB can send a WUS within a specific short time before the paging occasion (PO) arrives, and the WUS can indicate whether to send a paging message in the upcoming PO. The timing for sending the WUS signal should be shorter than the on-duration or the length of the PO to reduce power consumption.

[0137] By two or more serving cells, if WUS is also applied to carrier aggregation providing service to the UE, power consumption of the UE can be saved. The present disclosure proposes a method in which the UE operates to receive WUS if carrier aggregation is applied.

[0138] The method proposed in the present disclosure can set WUS in multiple serving cells, and if any of them is detected by the UE, the UE drives the on-duration timer. According to another condition, if it is already an active time for receiving the WUS or the upcoming on-duration is already considered to be an active time, the UE does not perform an operation of detecting the WUS.

[0139] The following Figures 9 to 11 A process in which a UE performs a DRX operation using a WUS according to various embodiments of the present disclosure is illustrated.

[0140] Fig. 9 is a flowchart illustrating a process in which a UE receives a WUS according to various embodiments of the present disclosure.

[0141] In step 905, the UE establishes an RRC connection with a serving cell (ie, a primary cell (PCell)).

[0142] In step 910, the UE receives configuration information related to DRX operation and WUS reception from the eNB.

[0143] In step 915, the UE determines a WUS timing for sending a WUS according to the configuration information. The WUS timing is implicitly determined using the information of the DRX cycle and the on-duration timing in the DRX configuration information, or the WUS timing is explicitly indicated from the eNB. For example, the timing from a specific OFDMA symbol immediately before the on-duration to a specific time point before the on-duration can be considered as a WUS timing. The specific OFDMA symbol can be preset, can be determined based on the amount of information of the WUS, or can be explicitly indicated by the eNB. There may be a specific timing between the WUS timing and the on-duration. This is the time taken for the UE to detect the WUS in the WUS timing, decode the WUS, and determine whether to maintain the active time within the on-duration. The specific timing can be preset or explicitly indicated by the eNB.

[0144] In step 920, the UE performs a first UE operation related to a DRX operation and a WUS reception operation in the PCell.

[0145] In step 925, the UE receives configuration information related to carrier aggregation from the eNB and sets two or more service cells. The eNB can set a specific service cell to which the WUS is sent. As an example, the specific service cell can be an SPCell such as a PCell. Alternatively, the WUS can be sent in all activated service cells. The eNB provides DRX configuration information on a cell group basis, and all activated service cells belonging to a cell group controlled by a single MAC entity apply the DRX configuration information. Therefore, for all service cells, the UE performs the same DRX operation with the same cycle and related timer values ​​applied.

[0146] In step 930, the UE performs a second UE operation related to a DRX operation and a WUS reception operation in a plurality of serving cells.

[0147] Fig.10 is a flowchart illustrating a process for a UE to perform a first UE operation according to various embodiments of the present disclosure.

[0148] In step 1005, the UE monitors the WUS at the WUS opportunity.

[0149] In step 1010, if WUS is detected in the WUS opportunity, the UE switches to the active time in the upcoming on-duration after the WUS opportunity, and drives the on-duration timer according to the following formula, ie, the on-duration starts.

[0150] If WUS is detected in a WUS opportunity (indicating a switch to an active time in the OnDuration where a WUS arrives), and a short DRX cycle is set, then

[0151] [(SFN×10)+subframe number]modulo(drx-ShortCycle)=(drx-StartOffset)modulo(drx-ShortCycle) or

[0152] If a WUS is detected in a WUS opportunity (indicating a switch to an active time in the OnDuration where a WUS arrives), and a long DRX cycle is set, then

[0153] [(SFN×10)+subframe number]modulo(drx-LongCycle)=drx-StartOffset

[0154] The OnDuration starts from the subframe position that satisfies the equation. However, if the eNB sets drx-SlotOffset, the OnDuration starts after the drx-SlotOffset value has passed from the derived subframe start time. The unit of drx-SlotOffset is time slot.

[0155] In step 1015, if no WUS is detected in the WUS opportunity, the UE does not switch to the active time in the upcoming on-Duration after the WUS opportunity.

[0156] Fig.11 is a flowchart illustrating a process in which a UE performs a second UE operation according to various embodiments of the present disclosure.

[0157] In step 1105, the UE monitors WUS in a WUS opportunity in a specific serving cell or in all activated serving cells. If the eNB is configured to send WUS only in a specific serving cell such as PCell, the eNB monitors WUS only in the WUS opportunity in the serving cell. Otherwise, if the eNB is configured to send WUS in all activated serving cells, the eNB monitors WUS in the same WUS opportunity in all activated serving cells.

[0158] In step 1110, if WUS is detected in at least one WUS opportunity in a specific serving cell or all activated serving cells, all serving cells switch to active time within the OnDuration coming after the WUS opportunity and drive the OnDuration timer.

[0159] If WUS is detected in a WUS opportunity (indicating a switch to an active time in the OnDuration where a WUS arrives), and a short DRX cycle is set, then

[0160] [(SFN×10)+subframe number]modulo(drx-ShortCycle)=(drx-StartOffset)modulo(drx-ShortCycle) or

[0161] If WUS is detected in a WUS opportunity (indicating a switch to an active time in the OnDuration where a WUS arrives), and a long DRX cycle is set, then

[0162] [(SFN×10)+subframe number]modulo(DRX-drx-LongCycle)=drx-StartOffset

[0163] The OnDuration of all activated serving cells starts at the subframe position that satisfies its expression. However, if the eNB sets drx-SlotOffset, the OnDuration of all activated serving cells starts after the derived OnDuration of the subframe passes the drx-SlotOffset value. The unit of drx-SlotOffset is time slot.

[0164] In step 1115, if no WUS is detected in any WUS opportunity in the specific serving cell or all activated serving cells, all serving cells do not switch to the active time within the on-duration after the WUS opportunity.

[0165] The following Figures 12 to 15 A process in which a UE performs a DRX operation using a WUS according to various embodiments of the present disclosure is illustrated.

[0166] Fig.12 A process of transmitting and receiving a WUS signal by a UE in an idle mode according to various embodiments of the present disclosure is illustrated.

[0167] Before the WUS opportunity 1210 arrives, the idle mode UE has a warm-up time 1205 required to drive the RF, modem, etc. The warm-up time of each UE depends on the implementation. The WUS opportunity (i.e., the opportunity to send WUS) is located before the arrival of PO. The starting time point of the WUS opportunity is explicitly indicated to the UE through system information 1215, or is implicitly determined to a specific time point before PO. As an example, the specific time point can be the start time of the synchronization sequence (SS) burst closest to the PO, or a time point before the time when a beam scanning cycle before the PO is combined with the specific opportunity 1240. The specific opportunity 1240 is necessary for the UE to decode the WUS and determine whether to monitor the paging message in the upcoming PO. The specific opportunity has a value greater than or equal to zero, and the eNB explicitly indicates the use of system information or the application of a preset value. Monitoring the paging message means monitoring the downlink control information (DCI) indicating the paging message and receiving the corresponding paging message.

[0168] In the WUS opportunity, if it is determined that a particular UE needs to monitor paging messages in the upcoming PO, the eNB sends a WUS for each of its transmit beams. The WUS is the same regardless of the beam. The eNB can identify which transmit beam the idle mode UE can best receive. Therefore, the WUS is sent for all transmit beams. As an example, if the eNB has eight transmit beams, a total of eight WUS1220 are sent using each transmit beam. UEs located in the service area of ​​the eNB detect the WUS from at least one transmit beam. In addition, these UEs can identify which beam successfully detected the WUS. The SSB corresponds to one beam, and one SS burst is configured by including multiple SSBs corresponding to the beams, respectively. If the SSB and WUS are combined and transmitted in a time division multiplexing (TDM) or frequency division multiplexing (FDM) scheme, the UE only monitors the timing of transmitting the SSB for various purposes including WUS monitoring, which is beneficial for optimizing power consumption. However, at some time before the arrival of the PO, the SS burst may not exist, and combining the WUS to an SS burst far away from the PO in the form of time division multiplexing (TDM) or frequency division multiplexing (FDM) may weaken the purpose of the WUS. As an example, if the WUS is combined to an SS burst far away from the PO in the form of TDM or FDM, the WUS does not reflect the paging that occurs between the SS burst and the PO. Therefore, if the PO is separated from the SS burst before the arrival of the PO over a specific time occasion, there is a WUS opportunity for sending the WUS for each transmit beam regardless of the SS burst. Otherwise, if the PO is separated from the SS burst before the arrival of the PO within a specific time occasion, the WUS is sent together with the SSB. The specific time period is explicitly indicated by the eNB to the UE through system information, or is implicitly determined as a specific time point before the PO.

[0169] A paging message for a specific UE in the NR will be sent in a paging occasion 1225, which is a specific occasion belonging to a specific paging frame (PF). The PO includes a plurality of time slots, and each time slot 1230 corresponds to a transmit beam of the eNB. Therefore, the number of time slots is equal to the number of transmit beams of the eNB. During the time slot, the eNB sends a paging message in the corresponding transmit beam. All paging messages sent for each time slot are the same. In idle mode, the eNB does not know the location of a specific UE and may not specify the most suitable transmit beam for the UE. Therefore, the eNB needs to send the same paging message through all transmit beams. The sequential transmission of signals through all transmit beams as described above is called beam scanning. Therefore, as the number of transmit beams increases, the length of the beam scanning cycle or PO increases proportionally. Generally, the UE also monitors paging in all transmit beams during the PO opportunity. The UE successfully decodes the paging received from at least one transmit beam.

[0170] An idle mode UE located in the service area of ​​the eNB first detects a WUS from at least one transmit beam. In this way, the UE can also identify which beam successfully detected the WUS. Therefore, there is no need to monitor paging in each transmit beam during the PO opportunity as in the case where there is no WUS operation. That is, since it is very likely that the paging is successfully decoded in the beam where the WUS is successfully detected, the UE monitors the paging only in the time slot 1240 of the PO corresponding to the beam. The UE can successfully decode WUS from multiple beams in the WUS opportunity. In some cases, the UE can select a beam that provides the maximum signal strength, or can randomly select a beam. The UE monitors the paging provided from the same beam in the time slot within the PO corresponding to the selected beam.

[0171] Fig.13 A process of transmitting and receiving a WUS signal by a UE in a connected mode according to various embodiments of the present disclosure is illustrated.

[0172] Before the WUS opportunity arrives, the connected mode UE has a warm-up time and beam management operation time 1305 required to drive the RF, modem, etc. The beam management operation is performed to maintain the best beam before the on-duration in the connected mode. The beam management operation mainly includes two steps. The first step is to measure the signal strength of the beam, and the second step is to report and update the eNB if the transmit beam pairing with the eNB needs to be adjusted. Therefore, after the beam management operation, the connected mode UE and the eNB believe that the best beam is maintained. For a specific UE in connected mode, the eNB that identifies which beam is the best only sends WUS or paging in the best beam, without having to send WUS or paging through a beam scanning operation as in an idle mode operation.

[0173] The WUS opportunity (the opportunity 1310 to send WUS) is located before the on-duration 1315 arrives. The time point of starting the WUS opportunity is explicitly indicated to the UE through system information or dedicated RRC signaling 1330, or is implicitly determined as a specific time point before the on-duration. As an example, the specific time point can be the start time point of the SS burst closest to the on-duration, or a time point before the time when a beam scanning cycle is combined with the specific opportunity 1335 before the on-duration. The specific opportunity 1335 is necessary for the UE to decode the WUS and determine whether to monitor the PDCCH within the upcoming on-duration. The specific opportunity has a value of 0 or greater, and the eNB explicitly indicates the use of system information or dedicated RRC signaling, or a preset value is applied. Monitoring PDCCH means that the UE identifies DL allocations or UL grants, that is, scheduling information provided by the eNB for itself.

[0174] In the WUS opportunity, if it is determined that a specific UE needs to monitor the PDCCH in the upcoming on-duration, the eNB sends a WUS in the best beam maintained or updated by the beam management operation. If the WUS is sent by combining the SSB with the WUS in the TDM or FDM scheme, the UE that only needs to monitor the timing of sending the SSB is advantageous in terms of optimizing power consumption for various purposes including WUS monitoring. However, in the specific opportunity before the on-duration arrives, the SS burst may not exist, and combining the WUS into the SS burst far away from the on-duration in the form of TDM or FDM may weaken the purpose of the WUS. As an example, if the WUS is combined into the SS burst far away from the on-duration in the form of TDM or FDM, the WUS does not reflect the paging that occurs between the SS burst and the on-duration. Therefore, if the on-duration is separated from the SS burst before the on-duration arrives outside the specific opportunity, there is a WUS opportunity to send the WUS through the best transmission beam regardless of the SS burst. Otherwise, if the on-duration is separated from the SS burst before the on-duration arrives in the specific opportunity, the WUS is sent together with the SSB. The specific time period is explicitly indicated to the UE by the eNB through system information, or is implicitly determined as a specific time point before the OnDuration.

[0175] The eNB can instruct the connected mode UE to configure CSI-RS in addition to SSB and perform cell measurement based on CSI-RS. If WUS is sent by combining CSI-RS with WUS using TDM or FDM scheme, UEs that only need to monitor the timing of CSI-RS for various purposes including WUS monitoring are advantageous in optimizing power consumption. However, at a specific time before the on-duration arrives, CSI-RS may not exist, and combining WUS to CSI-RS far away from the on-duration in TDM or FDM form may weaken the purpose of WUS. As an example, if WUS is combined into CSI-RS far away from the on-duration in TDM or FDM form, WUS does not reflect the scheduling that occurs between CSI-RS and the on-duration. Therefore, if the on-duration and the CSI-RS before the on-duration arrives are separated outside the specific timing, there is a WUS opportunity to send WUS through the best beam regardless of the CSI-RS. Otherwise, if the on-duration and the CSI-RS before the on-duration arrives are separated within a specific time period, the WUS is sent together with the CSI-RS. The specific time period is explicitly indicated to the UE by the eNB through system information, or is implicitly determined as a specific time point before the on-duration.

[0176] As mentioned above, WUS can be sent together with SSB or CSI-RS. Depending on whether a specific condition is met, the eNB explicitly indicates to the UE which of the SSB and CSI-RS is sent together with the WUS, or is set to use both SSB and CSI-RS, where the eNB sends WUS by combining with SSB or CSI-RS. For example, SSB or CSI-RS present in a specific timing of the upcoming on-duration is combined with WUS and sent together with WUS using TDM or FDM. If both SSB and CSI-RS are present at a specific timing, the preset or set one is sent together with WUS.

[0177] A connected mode UE located in the service area of ​​the eNB first detects the WUS from the best beam. The UE that identifies the best beam does not need to monitor the PDCCH in every transmit beam during the on-duration. That is, since the WUS can also successfully decode the PDCCH in the best beam, the eNB monitors the PDCCH 1320 only in the time slots in the on-duration corresponding to the beam.

[0178] Fig.14 is a flowchart of a process for a UE to receive a WUS signal in an idle mode according to various embodiments of the present disclosure.

[0179] In step 1405, the UE supporting WUS receives configuration information required to receive WUS from the eNB through system information.

[0180] In step 1410, the UE derives a timing to send a WUS. The WUS timing is between a warm-up timing required to turn on and prepare the RF or communication modem and an upcoming PO timing. If certain conditions are met, the WUS timing may match the location of the SS burst. The length of the WUS timing matches a beam scanning timing in which all transmit beams of the eNB sending the WUS may be transmitted.

[0181] In step 1415, the UE monitors the WUS at the derived WUS opportunity location.

[0182] In step 1420, the UE receives and decodes at least one WUS respectively transmitted through the transmission beams.

[0183] In step 1425, the UE monitors the paging message in the eNB transmission beam that sent the successfully decoded WUS. If the WUS is successful in multiple beams, the UE monitors the paging message in the beam that provides the maximum signal strength or in a beam randomly selected from multiple related beams. Alternatively, the UE can decode the paging message by soft combining the paging messages received from the corresponding beams.

[0184] Fig.15 is a flowchart of a process for a UE to receive a WUS signal in a connected mode according to various embodiments of the present disclosure.

[0185] In step 1505, the UE reports to the serving eNB that it supports WUS operation.

[0186] In step 1510, configuration information required to receive WUS from the eNB is provided to the UE.

[0187] The UE maintains the best transmit / receive beam by performing a beam management operation between the warm-up occasion and the WUS occasion in step 1515. If it is necessary to update the old best beam, the UE reports to the eNB to update with the new best transmit beam.

[0188] The UE receives and decodes the WUS in the best beam in step 1520. If the WUS is not sent in the WUS opportunity, or if the WUS indicates that PDCCH monitoring is not required, PDCCH monitoring does not need to be performed in the upcoming On-Duration.

[0189] In step 1525, the UE monitors the PDCCH in the best beam.

[0190] NR can send a UE that has no data transmission and reception within a specific time to RRC inactive mode / state instead of RRC idle mode. A UE in RRC inactive mode / state can have two types of paging areas, namely, RAN notification area (RNA) and core network tracking area (CNTA). Generally, a CN TA may include one or more RNAs. If the UE changes the RNA, an RNA update operation of the radio layer (i.e., access stratum (AS) level) is performed, and if the CN TA changes, a CN TA update operation of the core layer (i.e., non-access stratum (NAS) level) is performed. However, if the RNA appears at the boundary of the CN TA at the same time, the RNA and CN TA update operations are triggered independently, and in this case, the network may change the state of the UE unnecessarily. In the following, according to Figures 16 to 22 An embodiment of the present invention provides a method for effectively setting a paging area of ​​an RRC inactive mode / state UE and effectively managing the mobility of the RRC inactive mode / state UE by sending and processing a paging message to the UE in a NR.

[0191] Fig.16 An RRC inactive mode / state or an RRC light connected mode according to various embodiments of the present disclosure is shown.

[0192] The RRC inactive mode / state is a UE mode newly defined in addition to the idle mode or the connected mode to reduce signaling overhead due to handover and paging transmission operations. Fig.16 Assuming the NR gNB is connected to the LTE core network. If the NR core network is applied, it can also be applied Fig.16 A process where the specific name or detailed operations may be different.

[0193] The newly defined UE mode may be set to a mode other than the RRC inactive mode / state or the RRC light connected mode. Hereinafter, the newly defined UE mode is referred to as the RRC inactive mode / state.

[0194] The UE 1603 in RRC inactive mode / state stores the UE context of the UE and maintains the S1 connection, and paging is triggered by the anchor gNB 1602 and 1604 or the MME. The anchor gNBs 1602 and 1604 are gNBs that store the context of the UE and can manage the mobility of the UE. Accordingly, if there is data to be sent to the UE, the MME 1601 that recognizes the UE in connected mode immediately sends the data to the eNB instead of triggering paging first. The gNB that receives the data forwards the paging to all gNBs within a specific radio paging area, i.e., RNA 1605, and all gNBs send the paging.

[0195] Fig.17 An example of a process of establishing a connection with a network for a UE to transmit and receive data in a wireless communication system according to various embodiments of the present disclosure is shown.

[0196] A UE that is not currently connected, i.e., an idle mode UE 1701, performs an RRC connection establishment procedure with the gNB if data to be sent appears. UE 1701 establishes backward transmission synchronization with gNB 1702 through a random access procedure and sends an RRC connection request (RRCConnectionRequest) message 1705 to the gNB. The RRC connection request (RRCConnectionRequest) message includes an identifier of UE 1701 and an establishment cause (establishmentCause) for establishing a connection. gNB 1702 sends an RRC connection establishment (RRCConnectionSetup) message so that UE 1701 establishes an RRC connection 1710. The RRC connection establishment (RRCConnectionSetup) message includes RRC connection configuration information. The RRC connection establishment (RRCConnectionSetup) message is also called a signaling radio bearer (SRB) and is used to send and receive RRC messages, which are control messages between UE 1701 and gNB 1702. UE 1701 that establishes the RRC connection sends an RRC Connection Setup Complete message 1715 to gNB 1702. The RRC Connection Setup Complete message includes a control message SERVICE REQUEST that UE 1701 requests MME 1703 to establish a bearer for a specific service. gNB 1702 sends the SERVICE REQUEST message included in the RRC Connection Setup Complete message to MME 1720, and MME 1703 determines whether to provide the service requested by UE 1701. If it is determined according to the determination result that the service requested by UE 1701 is provided, MME 1703 sends an INITIAL CONTEXT SETUP REQUEST message 1725 to gNB 1702. The INITIAL CONTEXT SETUPREQUEST message includes quality of service (QoS) information to be applied in setting up a data radio bearer (DRB), and security related information to be applied to the DRB, such as security keys or security algorithm information. The gNB 1702 exchanges a SecurityModeCommand message 1730 and a SecurityModeComplete message 1735 with the UE 1701 to set up security.If the security establishment is completed, gNB 1702 sends an RRCConnectionReconfiguration message 1740 to UE 1701. The RRCConnectionReconfiguration message includes DRB establishment information for processing user data, and UE 1701 sets the DRB by applying the information and sends an RRCConnectionReconfigurationComplete message 1745 to gNB 1702. The gNB 1702 that completes the DRB establishment with the UE 1701 sends an INITIAL CONTEXT SETUP COMPLETE message 1750 to the MME 1703, and the MME 1703 that receives the INITIAL CONTEXT SETUP COMPLETE message exchanges an S1 bearer setup (BEARER SETUP) message 1755 and an S1 bearer setup response (BEARER SETUP RESPONSE) message 1760 with the S-GW 1704 to set up the S1 bearer. The S1 bearer is a connection configured between the S-GW and the gNB for data transmission, and corresponds one-to-one with the DRB. After completing all of the above processes, the UE 1701 sends and receives data 1765 and 1770 through the gNB 1702 and the S-WG 1704. In this way, the example of the data sending and receiving process mainly includes three steps: RRC connection configuration, security configuration, and DRB configuration.

[0197] Fig.18 1 is a signal flow diagram between a UE and a gNB for supporting an RRC inactive mode / state in a wireless communication system according to various embodiments of the present disclosure.

[0198] Specifically, Fig.18 The signaling process of UE 1801 and gNB 1803 for supporting RRC inactive mode / state in NR is shown, and the process of setting the paging area of ​​RRC inactive mode / state UE 1801 is shown. Fig.18 It is assumed that the NR gNB is connected to the LTE core network. Fig.18 The process may also be applied to the NR core network, where the specific names or detailed operations may be different.

[0199] Fig.18The signal flow of UE 1801, anchor gNB 1802, new gNB 1803, and MME 1804 for performing a process of reusing UE context and S1 bearer is shown. UE 1801 in RRC connected mode / state performs data transmission and reception with gNB 1802. If data transmission and reception stop, gNB 1802 may drive a specific timer, and if data transmission and reception are not resumed until timer expiration 1805, gNB considers releasing the RRC connection of the UE. gNB 1802 may release the RRC connection of UE 1801 according to a specific rule, then store the UE context and assign a resumption ID (UE context identifier), and at the same time send a control message that instructs UE 1801 to release the RRC connection, and sends paging area (PA) or RNA or RAN paging area or CN-based paging area configuration information so that the UE reports mobility in RRC inactive mode / state. In this case, the UE 1801 may need to store the UE context based on the recovery ID allocation, or the gNB 1802 may send a separate context retention indication for indicating that the UE 1801 operates in the RRC inactive mode / state and store the UE context through the RRC message 1810. In addition, if the UE is to reconfigure the RRC connection within the valid period, the RRC message may include period information for the gNB to maintain the context or a cell list for applying a process using the stored context. The paging area configuration information may include a paging area identifier or a RAN area ID or a CN-based paging area ID or a list of cell IDs, and may include an add / subtract indication for each cell ID. The add / subtract indication may be a 1-bit indication, and if the addition of a specific cell ID is indicated, the cell ID may be added to the paging area, and if the subtraction of a specific cell ID is indicated, the cell ID may be subtracted from the paging area. The RRC message 1810 may use an RRC Connection Release (RRCConnectionRelease) message, or may switch the UE 1801 to the RRC inactive mode / state by including configuration information using a newly defined RRC message. After releasing the RRC connection of UE 1801, gNB 1802 maintains the UE context and the S1 bearer 1815 of UE 1801. The S1 bearer indicates an S1 control bearer for exchanging control messages between gNB 1802 and MME 1804, and an S1 user plane bearer for exchanging user data between gNB 1802 and S-GW 1804. By maintaining the S1 bearer, if UE 1801 wants to configure an RRC connection in the same cell or the same gNB 1802, the process of S1 bearer configuration can be omitted. If the valid period expires, gNB 1802 may delete the UE context and release the S1 bearer.UE 1801 that receives the RRCConnectionRelease message of step 1810 switches to the RRC inactive mode / state.

[0200] The gNB 1802 sends a control message 1820 requesting connection suspension to the MME 1804. The MME 1804 receiving the control message may instruct the S-GW 1804 to request the MME to initiate a paging process when downlink data of the UE appears, instead of forwarding the downlink data to the gNB, and the S-GW 1804 may operate accordingly 1835, or the S-GW 1804 may directly forward the downlink data to the anchor gNB when downlink data of the UE 1801 appears, so that the anchor gNB 1802 generates and sends a paging message to the neighbor gNB 1835. That is, the anchor gNB 1802 receiving the downlink data stores the data in a buffer and continues the paging process. The anchor gNB 1802 refers to the gNB 1802 that maintains the UE context and S1-U bearer of the UE 1801.

[0201] The UE that receives the RRC Connection Release (RRCConnectionRelease) message 1810 including the context retention indication information and the recovery ID can release the RRC connection, drive the timer corresponding to the validity period, record the valid cell list in the memory, retain the current UE context in the memory without deleting the current UE context 1825, and switch to the RRC inactive mode / state. The above-mentioned UE context indicates various information related to the RRC configuration of the UE, and includes SRB configuration information, DRB configuration information, security key information, etc. Next, it is necessary to configure the RRC connection for any reason 1830. The UE 1801 that was not assigned a recovery ID or was not indicated with a context retention in the previous RRC connection release process according to Fig.17 1801, but a UE 1801 that has been assigned a recovery ID or instructed to switch to an RRC inactive mode / state in a previous RRC connection release process may attempt an RRC connection recovery process using a stored UE context. Depending on whether the network supports an RRC inactive mode / state (or a light connection), an RRC inactive mode / state UE 1801 may perform a RRC connection recovery process based on the stored UE context. Fig.17The operation may be performed by an example of an RRC connection establishment procedure, or the RRC connection recovery procedure may be performed using a stored UE context. In the present disclosure, each gNB or cell may include and send an indication to the system information as to whether each gNB or cell supports RRC inactive mode / state (or light connection). The indication may be included in the system information. The gNB's support for RRC inactive mode / state (or light connection) may mean that the following operations 1850, 1855, 1860, 1865, 1870, 1875, 1880, 1885, and 1890 may be set and supported by the corresponding gNB or the corresponding cell. If an RRC connection needs to be established, the RRC inactive mode / state UE 1801 reads the system information of the cell currently camped on. If the system information does not include an indication that the gNB or cell supports RRC inactive mode / state (or light connection), the UE may perform the operation according to Fig.17 However, if the system information includes an indication that the gNB or cell supports RRC inactive mode / state (or light connection), the UE 1801 may perform the RRC connection recovery procedure 1845 using the stored UE context. The RRC connection recovery procedure using the stored UE context is as follows.

[0202] First, UE 1801 sends a preamble in a first message to perform a random access procedure. If resource allocation is feasible according to the preamble received in the first message, gNB 1802 allocates corresponding uplink resources to UE 1801 using a second message. UE 1801 sends a resume request (ResumeRequest) message 1850 including the resume ID received in step 1810 based on the received uplink resource information. The message can be a modified message of the RRC Connection Request (RRCConnectionRequest) message or a newly defined message, such as an RRC Connection Resume Request (RRCConnectionResumeRequest) message. If UE 1801 in RRC inactive mode / state releases the connection from the existing anchor gNB 1802 and moves and camps on the cell of another gNB, the new gNB 1803 can obtain which gNB provides service to the corresponding UE 1801 by receiving and identifying the UE's resume ID. If the recovery ID is successfully received and identified, the new gNB 1803 performs context retrieval procedures 1855 and 1860 from the existing gNB 1802. The new gNB 1830 can retrieve the UE context from the existing gNB 1802 via the S1 or X2 interface.

[0203] If the new gNB 1803 receives the recovery ID but fails to successfully distinguish UE 1801 for some reason, the new gNB 1803 may send an RRCConnectionSetup message to the UE and Fig.17 The example of the RRC connection establishment process returns to the operation process. That is, if an RRC connection establishment (RRCConnectionSetup) message is sent to UE 1801 and UE 1801 receives the message, an RRC connection establishment complete (RRCConnectionSetupComplete) message can be sent to gNB 1803 to establish the connection. Alternatively, if the new gNB 1803 receives the recovery ID but fails to successfully distinguish UE 1801, for example, fails to retrieve the UE context from the existing anchor gNB 1802, the UE's connection can be rejected by sending an RRC Connection Release (RRCConnectionRelease) message or an RRC Connection Reject (RRCConnectionReject) to UE 1801, and can be tried again from the beginning. Fig.17 The general RRC connection establishment process described in .

[0204] The new gNB 1803 identifies the MAC-I 1865 based on the retrieved UE context. The MAC-I is a message authentication code calculated for a control message by the UE 1801 by applying the security information of the restored UE context (i.e., by applying security keys and security counters). The gNB 1803 identifies the integrity of the message using the MAC-I of the message, the security keys and security counters stored in the UE 1801 context, etc. The new gNB 1803 determines the establishment of an RRC connection to be applied to the UE 1801, and sends an RRCConnectionResume message including the establishment information to the UE 1870. The RRCConnectionResume message may be a control message including the RRC context reuse indicator information in the general RRCConnectionRequest message. Similar to the RRCConnectionSetup message, the RRCConnectionResume message includes various information related to the RRC connection establishment of the UE. If UE 1801 receives an RRC connection establishment (RRCConnectionSetup) message, an RRC connection is established based on the configuration information indicated in the RRC connection establishment (RRCConnectionSetup) message, but if an RRC connection recovery (RRCConnectionResume) message is received, an RRC connection is established by considering all stored configuration information and the configuration information indicated in the control message (incremental configuration). In summary, the configuration information to be applied can be determined by determining the indicated configuration information as delta information of the stored configuration information, and the configuration information or the UE context can be updated. For example, if the RRC connection recovery (RRCConnectionResume) message includes SRB configuration information, the SRB is configured by applying the indicated SRB configuration information, and if the RRC connection recovery (RRCConnectionResume) message does not include SRB configuration information, the SRB is configured by applying the SRB configuration information stored in the UE context.

[0205] UE 1801 establishes an RRC connection by applying the updated UE context and configuration information, and sends an RRCConnectionResumeComplete message 1875 to gNB 1803. A control message for requesting the release of the connection suspension is sent to the MME, and a request is made to reconfigure the S1 bearer to the new gNB 1803, 1880, and 1885. MME 1804 receiving the message instructs S-GW 1804 to reconfigure the S1 bearer to the new gNB 1803, and to process data related to UE 1801 normally. After the process is completed, UE 1801 resumes data transmission and reception in the cell in operation 1890.

[0206] In this process, if UE 1801, which is in RRC inactive mode / state by disconnecting from the existing anchor gNB 1802, does not move obviously and re-resides on the cell 1802 of the existing anchor gNB, the existing anchor gNB 1803 may not perform processes 1855 and 1860, and may only release the connection suspension of the S1 bearer without performing processes 1880 and 1885, retrieve the UE context of UE 1801 with reference to the resumption ID indicated in the third message, and thus reconfigure the connection in a method similar to the above process.

[0207] If data transmission and reception stop, the gNB 1803 drives a specific timer, and if data transmission and reception are not resumed until the timer expires 1895, the gNB 1803 considers releasing the RRC connection of the UE 1801. The gNB 1803 releases the RRC connection of the UE 1801 according to a specific rule, then stores the UE context, allocates a resumption ID while sending a control message instructing the UE 1801 to release the RRC connection, and sends PA or RNA or RAN paging area or CN-based paging area configuration information for the UE 1801 to report mobility during the RRC inactive mode / state 1897. If the UE 1899 in the RRC inactive mode / state leaves the configured paging area, a procedure for updating the paging area is performed. The paging area configuration information may include a list of paging area identifications or RAN area IDs or CN-based paging area IDs or cell IDs, and each cell ID may include an add / subtract indication. The add / subtract indication may be a 1-bit indication, and if the indication is an addition to a specific cell identifier, the cell ID may be added to the paging area, and if the indication is a subtraction to a specific cell identifier, the cell ID may be subtracted from the paging area. The RRC message of 1810 may use an RRC Connection Release (RRCConnectionRelease) message, or may switch the UE to an RRC inactive mode / state by including configuration information using a newly defined RRC message.

[0208] Fig.19 An example of paging area configuration of an RRC inactive mode / state UE in a wireless communication system according to various embodiments of the present disclosure is shown.

[0209] In the present disclosure, a method of setting a paging area of ​​an RRC inactive mode / state UE is as follows.

[0210] The first paging area provided to RRC inactive mode / state UEs in NR is the CN-based paging area or tracking area. This area is provided and applied equally to RRC idle mode UEs, and the tracking area or CN-based paging area can be indicated as a list of tracking area IDs or a list of new CN-based paging area IDs. If set Fig.18 The gNB can use the CN-based paging area ID or tracking area ID to set the paging area of ​​the RRC inactive mode / state UE based on the paging configuration information of the RRC message sent in 1810 or 1897. The CN-based paging area ID can be the paging area configuration information set to the RRC idle mode UE, or it can be a new area configuration information defined by the network (or MME or core network). The CN-based paging area ID can be broadcast in the system information of each cell, or it can be sent directly in the NRCN through a NAS message. That is, if each cell broadcasts the paging area ID with system information, it can be as follows Fig.19Paging areas 1905, 1910, and 1915 are logically determined as shown. A UE that receives a set paging area for an RRC inactive mode / state UE with a CN-based paging area ID can read the system information of each cell while moving, identify the CN-based paging area ID information in the system information, and if the CN-based paging area ID information does not correspond to the set paging area ID, determine the out-of-paging area and perform a process for updating the paging area. The paging configuration information of the RRC message may include one or more CN-based paging area IDs. The paging area establishment process for the RRC inactive mode / state UE in the first paging area can be performed by the anchor gNB or by the MME (or a specific entity of the network). Generally, the process is a NAS-based mobility and paging area management process. The anchor gNB can store the context of the UE and indicate the gNB that manages the mobility of the RRC inactive mode / state UE. The advantage of the above embodiment is that the paging area of ​​the UE can be easily set with fewer CN-based paging area IDs because the CN-based paging area ID can cover a very large area (multiple cells). However, since the paging area is quite large, it may take a long time for the network to find the UE by sending a paging message, and signaling overhead may occur because the paging message is delivered to multiple gNBs / cells.

[0211] The second paging area provided to RRC inactive mode / state UEs in NR is a RAN based paging area (RAN Notification Area or RAN Area).

[0212] If you set Fig.18 If the paging configuration information of the RRC message sent in 1810 or 1897 of the gNB is included, the gNB can set the paging area of ​​the RRC inactive mode / state UE by using the RAN-based paging area ID (RAN notification area ID or RAN area ID). The area covered by the RAN-based paging area ID may be smaller than the area covered by the CN-based paging area ID that may be set in the first paging area. In addition, the RAN-based paging area ID may be new area configuration information defined in the network and may be broadcast in the system information of each cell. That is, if each cell broadcasts the paging area ID with system information, it may be as follows Fig.19The paging area is determined logically as shown. A UE that receives the set paging area of ​​an RRC inactive mode / state UE with a CN-based paging area ID can read the system information of each cell while moving, identify the CN-based paging area ID information in the system information, and if the CN-based paging area ID information does not correspond to the set paging area ID, determine the paging out-area and perform a process for updating the paging area. The paging configuration information of the RRC message may include one or more RRC-based paging area IDs. The paging area establishment process for the RRC inactive mode / state UE in the second paging area may be performed by the anchor gNB, or may be performed by the MME (or a specific entity of the network). The anchor gNB may store the context of the UE and indicate the anchor gNB that manages the mobility of the RRC inactive mode / state UE. The advantage of the second paging area is that the paging area of ​​the UE can be easily set with fewer CN-based paging area IDs because the RAN-based paging area ID can cover a very large area (multiple cells). However, since the paging area is slightly larger, it may take a long time for the network to find the UE by sending a paging message, and signaling overhead may occur because the paging message is sent to very many gNBs / cells. However, by managing a paging area that is smaller than the first paging area, the paging message can be delivered to the UE faster with less signaling overhead. In addition, if a paging area is set, a list of cell IDs can be used to configure the paging area of ​​the RRC inactive mode / state UE. The area included in the cell identifier can be the smallest unit for setting the paging area. Therefore, the paging area can be set most specifically and diversely. In addition, the cell ID can be new area configuration information defined in the network and can be broadcast in the system information of each cell.

[0213] According to various embodiments of the present disclosure, if a paging area is set for an RRC inactive mode / state UE, assuming that the first paging area and the second paging area are changed at the same time (as in the example of the UE at position 1920), that is, assuming the case of changing from CN TAID1 to CN TAID2 and from RNAID5 to RNAID3, the RNA update procedure at the AS level and the CN area update procedure at the NAS level must be independently triggered and independently performed on the UE. However, if the above operation is performed, the state change and process of the UE are different, and accordingly, unexpected state changes and operations of the UE may occur. The following embodiments will describe this problem in detail in the corresponding case.

[0214] Fig. 20 An example of the operation of an RRC inactive mode / state UE according to various embodiments of the present disclosure is shown. Specifically, Fig. 20Embodiments of the present disclosure relate to UE operations if update operations of two paging areas are triggered simultaneously and if the paging areas of the RRC inactive mode / state UE are set to a CN-based paging area and a RAN-based paging area.

[0215] exist Fig. 20 In the UE 2001, the UE may switch to the RRC inactive mode / state for a specified reason. The specified reason may be that no data is sent and received at a specific time, or the network instructs the corresponding UE to switch to the inactive mode / state. The UE in the UE state may have received the setting of the first paging area (tracking area or CN-based paging area) and the second paging area (RAN notification area, RAN). The first paging area and the second paging area may be set and managed independently, and their sizes and configuration cells may be different, but in specific cases, that is, if the boundaries of the first paging area and the second paging area are the same, the UE may have to perform CN tracking area update (TAU) and RAN notification area update (RNAU) operations at the same time. Since the above two operations are triggered by a single event and are independent operations, if there is no specific cooperation between the gNB and the UE, independent operations must be performed.

[0216] If the above two events occur, in step 2005, UE 2001 may perform an AS-level RNA update procedure, and UE 2001 sends a recovery request message including a recovery ID based on the uplink resource information pre-received from gNB 2003. The message may be a modified message of the RRC Connection Request message or a newly defined message, such as an RRC Connection Resume Request message. In addition, the message may add an indication indicating that UE 2001 requests recovery and that the corresponding request is an RNA update for the request reason. The RRC message may attempt to update the tracking area or paging area through mobile originated signaling (mo-signaling), mobile originated signaling RRC establishment cause (RRCestablishmentCause). In this case, if the recovery ID is successfully received and identified, gNB 2003 performs a process of retrieving the UE context from the existing gNB and performs an RNA update for the corresponding UE. In step 2010, gNB 2003 sends an RRC connection reconfiguration message and identifies the RNA update operation. In this operation, gNB 2003 may provide the newly updated RNAID information. In the AS-level RNA update procedures 2005 and 2010, UE 2001 may not switch to the RRC connected state. This is because if UE 2001 requests RRC recovery, an indication indicating the RRC update or request reason is included, so gNB 2003 does not have to switch the corresponding UE 2001 to the RRC connected state.

[0217] The NAS-level CN ​​TAU procedure may be performed simultaneously with the AS-level RNA update procedures 2005 and 2010. That is, if the UE 2001 moves from the pre-received CN paging area to the new CN paging area, the UE 2001 performs TAU procedures 2015, 2020, and 2025 on the MME or NR CN. The UE 2001 may send an RRC Connection Request (RRCConnectionRequest) message or an RRC Connection Resume Request (RRCConnectionResumeRequest) message and an indication indicating TAU to the gNB 2003 in step 2015, and the gNB 2003 may send an RRC message including a TAU Accept message to the UE 2001 in step 2020. For example, the TAU Accept message may be included in a DedicatedInfoNAS or DLInformationTransfer message of an RRCConnectionReconfiguration message and delivered to the UE 2001. The RRC message may attempt to update the tracking area or paging area through mobile originated signaling (mo-signaling) or mobile originated signaling RRC connection establishment Cause (RRC connection establishment Cause). In this case, a process to distinguish between TAU and RAN update operation requests may be necessary. Next, UE 2001 sends an RRC Connection Reconfiguration Complete message to gNB 2003 indicating that the corresponding TAU acceptance message is well received and switches to the RRC connected state. This is to allow UE 2001 to deliver NAS CN messages to MME or NR CN through SRB, for which UE 2001 must switch to the RRC connected state. If CN fails to send a response message to UE 2001 within the inactivity timer set in the above steps, UE 2001 may return to the RRC inactive state. UE 2001 may return to the RRC inactive mode / state and move according to the user's movement. UE 2001 may leave the set tracking area or paging area due to mobility, identify the tracking area or paging area ID in the system information of the current cell, and if it is identified that UE 2001 is outside the set tracking area or paging area, perform the tracking area or paging area update procedure. If the CN response message suspended in step 2040 arrives again, the CN delivers paging to UE 2001 and re-requests RRC connection and CN response message reception from UE 2001.After downlink data appears and paging is received from gNB 2003 in step 2045, transition to RRC connected state and data transmission and reception 2050, 2055, 2060, and 2065 may be performed. Next, gNB 2003 may disconnect from UE 2001 for specific reasons 2070 and 2075. The specific reason may be that there is no data transmission and reception between UE 2001 and the network within a specific time, so the inactivity timer expires. UE 2001 switches back to RRC inactive mode / state through the corresponding process.

[0218] Fig. 20 A problematic part in the embodiment may be that, in operation 2040, the response NAS message of the CN is not delivered at an appropriate time, and therefore, the state of the UE 2001 transitions to RRC Inactive and returns to RRC Connected.

[0219] Fig.21 An example of the operation of an RRC inactive mode / state UE according to various embodiments of the present disclosure is shown. Specifically, Fig.21 Depicted is an operation of a UE for updating corresponding paging areas if a CN-based paging area and a RAN-based paging area of ​​an RRC-inactive UE proposed in the present disclosure are simultaneously updated.

[0220] Out of Fig.21 For some reasons, UE 2101 may transition to RRC inactive mode / state. Some reasons may be that no data is sent and received at a specific time, or the network instructs the corresponding UE to switch to inactive mode / state. UE 2101 in UE state may have received the configuration of a first paging area (tracking area or CN-based paging area) and a second paging area (RAN notification area, RNA). The first paging area and the second paging area may be set and managed independently, and their sizes and configuration cells may be different, but in certain cases, that is, if the boundaries of the first paging area and the second paging area are the same, UE 2101 may have to perform CN TAU and RNAU operations at the same time. Since the above two operations are triggered by a single event and are independent operations, if there is no specific cooperation between UE 2101 and gNB 2103, independent operations must be performed.

[0221] If these two events occur, UE 2101 can perform CN TAU operation and AS-level RNA update process independently at the same time. Fig. 20In the above process of the embodiment, in step 2040, the response NAS message of the CN is not sent at an appropriate time, so the state of the UE may be switched to the RRC inactive state and then to the RRC connected state. Therefore, it is necessary to prevent such unwanted operations.

[0222] From the UE's perspective, the solution to this problem can be summarized as follows:

[0223] 1. In terms of UE implementation, the operation of the UE is optimized through the coordination of the AS level and the NAS level of the UE 2101. That is, if the AS-level RNA update and the NAS-level TAU occur at the same time, information is shared with each other and the corresponding information is delivered as AS and NAS messages, or the UE 2101 recognizes by itself that both the RAN update and the TAU operations should be performed, and unnecessary state transition operations of the UE 2101 are not performed until the corresponding operations are performed.

[0224] 2. The UE 2101 does not transmit RNA update and RRC connection recovery messages of TAU independently, but integrates them into one, and thus requests RRC connection from the network. For the corresponding method, the following solution may be further required.

[0225] A. If an RRC Connection Resume Request message is sent, UE 2101 adds an establishment cause indicating RAN-Update and indicates that NAS data is delivered via SRB in the corresponding RRC message, and simultaneously delivers a buffer status report (BSR) requesting its required resources. If gNB 2103 receives the corresponding message, the UE requests RAN update and simultaneously requests an RRC connection for TAU.

[0226] B. If the NAS-level TAU operation does not occur and only the RAN update occurs, the UE 2101 includes only the establishment cause indicating the RAN update when sending the RRC Connection Resume Request message. That is, the UE 2101 does not add a BSR for NAS data transmission. In this case, the UE 2101 does not switch to the RRC connected state.

[0227] C. If the AS-level RNA operation does not occur and only the TAU operation occurs, the UE 2101 includes only the establishment cause indicating the mobile-originated signaling (mo-signaling) or the mobile-originated signaling when sending the RRC Connection Resume Request message. In this case, the BSR for NAS data transmission may be added or not.

[0228] The establishment reason defined in the step can be configured in other forms.

[0229] From the network's perspective, UE 2101 can identify whether the CN TAU process and RNA update operation occur simultaneously through the above solution, and the corresponding integrated process can prevent unnecessary operations of switching UE 2101 to the RRC inactive state before UE 2101 receives the CN response message.

[0230] Fig. 22 An example of the operation of an RRC inactive mode / state UE according to various embodiments of the present disclosure is shown. Specifically, Fig. 22 is a diagram of an operation of a UE when an RRC inactive mode / state UE performs a procedure for updating a paging area proposed in the present disclosure.

[0231] exist Fig. 22 In the step 2201, the UE 2201 may receive an RRC connection release message or a newly defined RRC message from the eNB and switch to the RRC inactive mode / state. The UE that receives the RRC message identifies whether the paging configuration information exists 2210. The RRC message may include a UE context identifier and paging area configuration information. In the UE state, the UE may have received the configuration of the first paging area (tracking area or CN-based paging area) and the second paging area (RAN notification area, RNA). The first paging area and the second paging area may be configured and managed independently, and their sizes and configuration cells may be different, but in a specific case, that is, if the boundaries of the first paging area and the second paging area are the same, the UE may need to perform CN TAU and RNAU at the same time. Since the above two operations are triggered by a single event and are independent operations, independent operations are inevitable if there is no specific cooperation between the eNB and the UE. In step 2215, the UE stores the received TA and RNA information and checks the corresponding areas. That is, the UE reads system information from the cell when moving and determines whether the corresponding information is updated.

[0232] If the UE has a TA or RNA update in step 2220, if only the TAID is changed to correspond to the TAU, the UE performs a TA update operation in step 2225. If only the RNAID is changed in step 2130, the RNA update operation is performed, and if both IDs are changed in step 2235, the TA and RNA are updated simultaneously. Fig.21 The above-mentioned TA update, RNA update, and TA and RNA simultaneous update operations have been described in the embodiments.

[0233] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in software, hardware, or a combination of hardware and software.

[0234] As for software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in a computer-readable storage medium may be configured to be executed by one or more processors of an electronic device. One or more programs may include instructions for causing an electronic device to perform a method according to an embodiment described in the claims or specification of the present disclosure.

[0235] Such a program (software module, software) may be stored in a random access memory, a nonvolatile memory (including flash memory), a read only memory (ROM), an electrically erasable programmable ROM (EEPROM), a magnetic disk storage device, a compact disc (CD) ROM, a digital versatile disc (DVD) or other optical storage device and a magnetic tape. Alternatively, the program may be stored in a memory combining part or all of these recording media. A plurality of memories may be provided.

[0236] In addition, the program can be stored in an attachable storage device accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a communication network that combines these networks. The storage device can access the electronic device through an external port. In addition, a separate storage device on the communication network can access the device that meets the embodiments of the present disclosure.

[0237] In the specific embodiments of the present disclosure, the elements included in the present disclosure are represented in singular or plural form. However, for ease of explanation, singular or plural expression is appropriately selected according to the situation proposed, and the present disclosure is not limited to a single element or multiple elements. The element represented in plural form can be configured as a single element, and the element represented in singular form can be configured as multiple elements.

[0238] At the same time, although specific embodiments have been described in the explanation of the present disclosure, it should be noted that various changes can be made therein without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure is not limited or defined by the described embodiments, and is limited not only by the scope of the attached claims, but also by the equivalent forms of the attached claims.

Claims

1. A method for operating a user equipment UE in a wireless communication system, the method comprising: Sending a first RRC message requesting restoration of a radio resource control RRC connection to a base station BS, the first RRC message including cause information, wherein the UE is in an RRC inactive state; and receiving a second RRC message as a response to the first RRC message from the BS, wherein the RRC inactive state of the UE is maintained, wherein, in the case where a Tracking Area Update (TAU) and a Radio Access Network (RAN) Notification Area (RNA) Update are triggered simultaneously, the cause information indicates a Mobile Originated (MO) signaling, and Wherein, when RNA update is triggered, the cause information indicates the update of RNA.

2. The method according to claim 1, wherein: The second RRC message includes information on the updated RNA.

3. A method for operating a base station in a wireless communication system, the method comprising: receiving a first RRC message requesting resumption of a radio resource control RRC connection from a user equipment UE, the first RRC message including cause information, wherein the UE is in an RRC inactive state; and sending a second RRC message as a response to the first RRC message to the UE, wherein the RRC inactive state of the UE is maintained, wherein, in the case where a Tracking Area Update (TAU) and a Radio Access Network (RAN) Notification Area (RNA) Update are triggered simultaneously, the cause information indicates a Mobile Originated (MO) signaling, and Wherein, when RNA update is triggered, the cause information indicates the update of RNA.

4. The method according to claim 3, wherein: The second RRC message includes information on the updated RNA.

5. A user equipment UE in a wireless communication system, the UE comprising: Transceiver; as well as at least one processor, wherein the at least one processor is configured to, Sending a first RRC message requesting restoration of a radio resource control RRC connection to a base station BS, the first RRC message including cause information, wherein the UE is in an RRC inactive state; and receiving a second RRC message as a response to the first RRC message from the BS, wherein the RRC inactive state of the UE is maintained, wherein, in the case where a Tracking Area Update (TAU) and a Radio Access Network (RAN) Notification Area (RNA) Update are triggered simultaneously, the cause information indicates a Mobile Originated (MO) signaling, and Wherein, when RNA update is triggered, the cause information indicates the update of RNA.

6. The UE according to claim 5, wherein: The second RRC message includes information on the updated RNA.

7. A base station BS in a wireless communication system, the BS comprising: Transceiver; as well as at least one processor, wherein the at least one processor is configured to, receiving a first RRC message requesting resumption of a radio resource control RRC connection from a user equipment UE, the first RRC message including cause information, wherein the UE is in an RRC inactive state; and sending a second RRC message as a response to the first RRC message to the UE, wherein the RRC inactive state of the UE is maintained, wherein, in the case where a Tracking Area Update (TAU) update and a Radio Access Network (RAN) Notification Area (RNA) update are triggered simultaneously, the cause information indicates a Mobile Originated (MO) signaling, and Wherein, when RNA update is triggered, the cause information indicates the update of RNA.

8. The BS according to claim 7, wherein: The second RRC message includes information on the updated RNA.

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