KR102425069B1 - Method and appatarus for supporting discontinuous reception mode of connected mode in mobile communication system - Google Patents

Abstract

The present disclosure relates to a communication technique that converges a 5G communication system for supporting a higher data rate after a 4G system with IoT technology, and a system thereof. The present disclosure provides intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on 5G communication technology and IoT-related technology. ) can be applied to One embodiment of the present invention relates to a method and apparatus for effectively supporting a discontinuous reception mode in a connected mode in a next-generation mobile communication system.

Description

METHOD AND APPATARUS FOR SUPPORTING DISCONTINUOUS RECEPTION MODE OF CONNECTED MODE IN MOBILE COMMUNICATION SYSTEM

The present invention relates to a method and apparatus for effectively supporting a discontinuous reception mode in a connected mode in a next-generation mobile communication system.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G Network) communication system or the LTE system after (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to alleviate the path loss of radio waves and increase the propagation distance of radio waves in the very high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud radio access network: cloud RAN), an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway. In addition, in the 5G system, the advanced coding modulation (ACM) methods FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), and advanced access technologies FBMC (Filter Bank Multi Carrier), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication) are implemented by 5G communication technologies such as beamforming, MIMO, and array antenna. will be. The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

In the existing LTE technology, only two DRX (Discontinuous Reception) cycles can be set, so it is impossible to dynamically change the DRX cycle according to various DRB characteristics, traffic patterns, buffer states, and the like.

This specification proposes a DRX operation capable of dynamically changing the DRX cycle or drx-InactivityTimer according to various DRB characteristics, traffic patterns, buffer states, and the like.

The present invention for solving the above problems is a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; processing the received first control signal; and transmitting a second control signal generated based on the processing to the base station.

According to an embodiment of the present invention, signal overhead can be reduced for a terminal configured with a carrier direct technology including at least one low-frequency cell and a high-frequency cell.

1A is a diagram showing the structure of a next-generation mobile communication system.
1B is an exemplary diagram of a frame structure used by the NR system to which the first embodiment of the present invention is applied.
1C is a diagram for explaining a carrier direct scenario between a cell using a low frequency band and a cell using a high frequency band considered in the present invention.
1D is a diagram for explaining a DRX operation.
FIG. 1E is a diagram for explaining a process of performing beam alignment before PDCCH monitoring.
1F is a diagram for explaining a process of performing a DRX operation of a cell performing a beam-based operation according to the first embodiment of the present invention.
1G is a flowchart illustrating an operation of a terminal performing DRX according to the first embodiment of the present invention.
1H is a diagram for explaining a process in which a UE transmits a Scheduling Request and receives radio resource allocation from a base station in an existing LTE system.
1I is a diagram for explaining a process of performing a scheduling request operation of a cell performing a beam-based operation according to the first embodiment of the present invention.
1J is a flowchart illustrating an operation of a terminal performing SR according to the first embodiment of the present invention.
1K is a block diagram illustrating an internal structure of a terminal according to a first embodiment of the present invention.
11 is a block diagram showing the configuration of a base station according to the first embodiment of the present invention.
2A is a diagram illustrating the structure of a next-generation mobile communication system.
2B is a diagram for explaining a method of determining whether access is granted in the existing LTE system.
2C is a diagram for explaining a wireless connection state transition in a next-generation mobile communication system.
2D is a diagram for explaining a process of performing an access connection in an RRC INACTIVE state according to a second embodiment of the present invention.
2E is a diagram for explaining an operation of a terminal AS performing an access connection in an RRC INACTIVE state according to a second embodiment of the present invention.
2F is a block diagram illustrating an internal structure of a terminal according to a second embodiment of the present invention.
2G is a block diagram showing the configuration of a base station according to a second embodiment of the present invention.
3A is a diagram illustrating the structure of an LTE system.
3B is a diagram illustrating a radio protocol structure of an LTE system.
3C is a diagram illustrating a message flow between a terminal and a base station when the first method for inter-cell handover is used according to the third embodiment of the present invention.
3D is a diagram illustrating an operation sequence of a terminal when using the first method for inter-cell handover according to the third embodiment of the present invention.
3E is a diagram illustrating a message flow between a terminal and a base station when the second method of inter-cell handover is used according to the third embodiment of the present invention.
3F is a diagram illustrating an operation sequence of a terminal when using the second method of inter-cell handover according to the third embodiment of the present invention.
3G is an exemplary block configuration diagram of a terminal according to a third embodiment of the present invention.
4A is a diagram illustrating the structure of an LTE system.
4B is a diagram illustrating a radio protocol structure in an LTE system.
4C is a diagram showing the structure of a next-generation mobile communication system.
4D is a diagram illustrating a radio protocol structure of a next-generation mobile communication system. .
4E is a diagram illustrating modes in which a terminal can stay in a next-generation mobile communication system according to a fourth embodiment of the present invention.
4f is a diagram illustrating a procedure for a terminal to switch from an RRC connected mode to an RRC idle mode and an RRC connected mode from an RRC idle mode according to a fourth embodiment of the present invention. It is a diagram explaining the procedure for switching to connected mode).
4G is a procedure for the terminal according to the fourth embodiment of the present invention to switch from the RRC connected mode to the RRC inactive mode (or lightly-connected mode) and the RRC inactive mode (or lightly-connected mode) to the RRC connected mode. A diagram showing the procedure.
4H is a diagram illustrating a response of a base station after performing a LAN paging area update procedure when a terminal according to a fourth embodiment of the present invention moves out of a currently set LAN paging area while moving in an RRC inactive mode (or lightly-connected mode). It is a drawing.
4I is a diagram illustrating one deployment scenario in which a next-generation mobile communication system and an LTE system coexist according to a fourth embodiment of the present invention.
FIG. 4j is a method for supporting mobility of a terminal in an RRC deactivation mode (lightly connected mode) when a terminal accessing a cell supported by the LTE system according to the fourth embodiment of the present invention moves to a cell supported by the next-generation mobile communication system It is a diagram showing the procedure for
FIG. 4K is a method for supporting mobility of a terminal in an RRC deactivation mode (lightly connected mode) when a terminal accessing a cell supported by the next-generation mobile communication system according to the fourth embodiment of the present invention moves to a cell supported by the LTE system. It is a diagram showing the procedure for
4L is a diagram illustrating an operation of a terminal supporting mobility of an RRC deactivation mode/Lightly connected mode terminal in different radio access schemes according to a fourth embodiment of the present invention.
4M is a diagram showing the structure of a terminal according to a fourth embodiment of the present invention.
4n is a diagram illustrating a block configuration of a TRP in a wireless communication system according to a fourth embodiment of the present invention.

Hereinafter, the operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms described below are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

In the following description of the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

A term for identifying an access node used in the following description, a term referring to network entities, a term referring to messages, a term referring to an interface between network objects, a term referring to various identification information and the like are exemplified for convenience of description. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

For convenience of description below, the present invention uses terms and names defined in the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present invention is not limited by the above terms and names, and may be equally applied to systems conforming to other standards.

<First embodiment>

1A is a diagram showing the structure of a next-generation mobile communication system.

1A, as shown, the radio access network of the next-generation mobile communication system consists of a next-generation base station (New Radio Node B, hereinafter NR NB) (1a-10) and NR CN (1a-05, New Radio Core Network). is composed A user terminal (New Radio User Equipment, hereinafter NR UE or terminal) 1a-15 accesses an external network through NR NB 1a-10 and NR CN 1a-05.

In FIG. 1A , NR NBs 1a-10 correspond to an Evolved Node B (eNB) of an existing LTE system. The NR NB is connected to the NR UE 1a-15 through a radio channel and can provide a service superior to that of the existing Node B. In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device for scheduling by collecting status information such as buffer status, available transmission power status, and channel status of UEs is required. (1a-10) is in charge. One NR NB typically controls multiple cells. In order to implement ultra-high-speed data transmission compared to existing LTE, it can have more than the existing maximum bandwidth, and additional beamforming technology can be grafted by using Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a radio access technology. . In addition, an Adaptive Modulation & Coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel state of the terminal is applied. The NR CN (1a-05) performs functions such as mobility support, bearer setup, QoS setup, and the like. NR CN is a device in charge of various control functions as well as mobility management functions for the terminal and is connected to a number of base stations. In addition, the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN is connected to the MME (1a-25) through a network interface. The MME is connected to the existing base station eNB (1a-30).

1B is an exemplary diagram of a frame structure used by an NR system to which the present invention is applied.

The NR system can consider the scenario of operating at high frequency to secure a wide frequency bandwidth for high transmission speed, and the scenario of transmitting data by generating a beam at high frequency due to difficulties in signal transmission.

Accordingly, the base station, or the Transmission Reception Point (TRP) (1b-01) is the terminals (1b-71) (1b-73) (1b-75) (1b-77) (1b-79) in the cell When communicating with ), a scenario in which different beams are used to communicate can be considered. That is, in this example drawing, terminal 1 (1b-71) communicates using beam #1 (1b-51), and terminal 2 (1b-73) communicates using beam #5 (1b-55), It is assumed that terminals 3, 4, and 5 (1b-75) (1b-77) (1b-79) communicate through beam #7 (1b-57).

In order to measure which beam the terminal uses to communicate with the TRP, an overhead subframe (osf) (1b-03) exists in time, and in the osf, the base station is symbol-by-symbol (or across several symbols) A reference signal is transmitted using different beams. A beam index value for distinguishing each beam may be derived from the reference signal. In this exemplary drawing, it is assumed that there are 12 beams from #1 (1b-51) to #12 (1b-62) as beams transmitted by the base station, and different beams are swept for every symbol in the osf. It is assumed that the transmission That is, each beam is transmitted for each symbol in the osf (for example, beam #1 (1b-51) is transmitted in the first symbol (1b-31)), the terminal measures the osf, and any beam transmitted in the osf It is possible to measure whether the signal from is the strongest.

In this exemplary drawing, it is assumed that the corresponding osf is repeated every 25 subframes, and the remaining 24 subframes are data subframes (data subframes, dsf) (1b-05) in which general data is transmitted and received.

Accordingly, according to the scheduling of the base station, the terminals 3, 4, 5 (1b-75) (1b-77) (1b-79) communicate using the beam #7 in common (1b-11), and the terminal 1 It is assumed that (1b-71) communicates using beam #1 (1b-13), and terminal 2 (1b-73) communicates using beam #5 (1b-15).

In this exemplary drawing, the transmission beams #1 (1b-51) to #12 (1b-62) of the base station are mainly diagrammed, but the reception beam of the terminal for receiving the transmission beam of the base station (eg, the terminal 1) (1b-81) (1b-83) (1b-85) (1b-87)) of (1b-71) can be further considered. In this exemplary drawing, the terminal 1 has four beams 1b-81, 1b-83, 1b-85, and 1b-87, and performs beam sweeping to determine which beam has the best reception performance. carry out In this case, when multiple beams cannot be used at the same time, one receive beam is used for each osf, and multiple osfs are received as many as the number of receive beams to find the optimal transmit beam of the base station and the receive beam of the terminal.

1C is a diagram illustrating a carrier direct scenario between a cell using a low frequency band and a cell using a high frequency band considered in the present invention. In a next-generation mobile communication system, it is applicable to both a low frequency band and a high frequency band. Cells 1c-10 having a low frequency of 6 GHz or less generally form a service area using an omni-directional antenna or a sector antenna. On the other hand, since the cell 1c-20 having a high frequency of 6 GHz or higher has a large radio path loss rate, a service area is guaranteed by applying a beam antenna that concentrates the antenna gain within a very narrow angle. One UE may use carrier aggregation to increase the peak throughput of the UE. In the carrier direct technology, the terminal may be connected to two or more cells at the same time to transmit and receive data. Also, the plurality of cells may be configured in a low frequency band and a high frequency band (1c-25, 1c-30). In the present invention, consider a terminal configured with carrier direct technology consisting of at least one low frequency cell and at least one high frequency cell.

1D is a diagram for explaining a DRX operation. DRX is applied to minimize power consumption of the UE, and is a technology for monitoring only a predetermined PDCCH to obtain scheduling information. DRX can operate in both standby mode and connected mode, and the operation method is slightly different. The present invention relates to a connected mode. In order for the UE to acquire scheduling information, it will cause large power consumption to continuously monitor the PDCCH. A basic DRX operation has a DRX cycle (1d-00) and monitors the PDCCH only for an on-duration (1d-05) time. In connected mode, two values of long DRX and short DRX are set for the DRX cycle. In a general case, a long DRX cycle is applied, and if necessary, the base station may trigger a short DRX cycle using a MAC CE (Control Element). After a certain time elapses, the UE changes from a short DRX cycle to a long DRX cycle. Initial scheduling information of a specific UE is provided only in the predetermined PDCCH. Accordingly, the UE periodically monitors only the PDCCH, thereby minimizing power consumption. If scheduling information for a new packet is received by the PDCCH during the on-duration (1d-05) time (1d-10), the UE starts the DRX inactivity timer (1d-15). The UE maintains the active state during the DRX inactivity timer. That is, PDCCH monitoring is continued. It also starts the HARQ RTT timer (1d-20). The HARQ RTT timer is applied to prevent the UE from unnecessarily monitoring the PDCCH during the HARQ Round Trip Time (RTT) time, and during the timer operation time, the UE does not need to perform PDCCH monitoring. However, while the DRX inactivity timer and the HARQ RTT timer are operating at the same time, the UE continues monitoring the PDCCH based on the DRX inactivity timer. When the HARQ RTT timer expires, the DRX retransmission timer (1d-25) is started. While the DRX retransmission timer is operating, the UE must perform PDCCH monitoring. In general, during the DRX retransmission timer operation time, scheduling information for HARQ retransmission is received (1d-30). Upon receiving the scheduling information, the UE immediately stops the DRX retransmission timer and starts the HARQ RTT timer again. The above operation continues until the packet is successfully received (1d-35).

Configuration information related to the DRX operation in the connected mode is delivered to the terminal through the RRCConnectionReconfiguration message. The on-duration timer, DRX inactivity timer, and DRX retransmission timer are defined by the number of PDCCH subframes. After the timer starts, when a set number of subframes defined as PDCCH subframes pass, the timer expires. In FDD, all downlink subframes belong to PDCCH subframes, and in TDD, downlink subframes and special subframes correspond to them. In TDD, a downlink subframe, an uplink subframe, and a special subframe exist in the same frequency band. Among them, the downlink subframe and the special subframe are considered as PDCCH subframes.

The base station can set two states of longDRX and shortDRX. In general, the base station will use one of the two states in consideration of the power Preference Indication information reported from the terminal, the terminal mobility record information, and the characteristics of the configured DRB. The transition between the two states is made by transmitting whether a specific timer expires or a specific MAC CE to the UE.

In the existing LTE technology, since only two DRX cycles can be set, it is impossible to dynamically change the DRX cycle according to various DRB characteristics, traffic patterns, and buffer conditions.

The present invention proposes a DRX operation capable of dynamically changing the DRX cycle or drx-InactivityTimer according to various DRB characteristics, traffic patterns, buffer states, and the like. In particular, it is characterized in that a default DRX cycle or a default drx-InactivityTimer is set, and the DRX cycle is dynamically changed using MAC CE. As another embodiment, when the UE reports a beam measurement report, particularly a new optimal beam, a method of stopping the configured DRX operation and maintaining the Active Time is proposed.

FIG. 1E is a diagram for explaining a process of performing beam alignment before PDCCH monitoring. At a high frequency of 6 GHz or more, a beam antenna-based mobile communication system is suitable. However, additional procedures are required to support such a beam antenna-based operation. One of them is a beam alignment operation. In a low frequency band, the base station generally uses an omni-directional antenna or a sector antenna, and the terminal uses an omni-directional antenna. Therefore, in order to transmit and receive data, there is no need to perform antenna alignment in advance. However, when at least one of the base station or the terminal applies a beam antenna, a beam alignment operation of determining which beam antenna to use for data transmission and reception is required. For example, when the UE performs a DRX operation, that is, periodic PDCCH monitoring (1e-15) in a beam antenna-based mobile communication system, a beam alignment operation (1e-20) is required in advance. Typically, the beam alignment operation consists of beam measurement (1e-05), the measurement result report, and a beam change procedure (1e-10). Since the beam alignment operation is not required in a non-beam antenna-based system, it can be viewed as a kind of overhead imposed by applying a beam antenna-based system. Therefore, the present invention proposes a method of minimizing the overhead for a terminal configured with a carrier direct technology including at least one low-frequency cell and a high-frequency cell.

1F is a diagram for explaining a process of performing a DRX operation of a cell performing a beam-based operation in the present invention.

The terminal 1f-05 establishes an RRC connection with the first cell 1f-10 (1f-20). A low frequency band is applied to the first cell, and beam alignment is not required using an omnidirectional or sector antenna. A carrier direct technique is configured for the purpose of improving peak throughput for the UE. To this end, the first cell exchanges configuration information with the second cell (1f-15) (1f-25), and adds the second cell as a serving cell of the terminal (1f-30). Since the second cell uses a high frequency band, a beam antenna is applied. In addition, the first cell transmits DRX configuration information for the first cell and the second cell to the terminal (1f-35). Upon receiving this, the terminal drives the DRX operation (1f-40). In the present invention, only the DRX operation for the first cell is driven, and the DRX operation for the second cell is driven when a specific condition is satisfied. The specific condition is when beam alignment is driven. Beam alignment may be started by receiving a message indicating beam alignment for the second cell from the first cell. The beam alignment instruction may be explicitly provided to the UE using a specific MAC CE (Control Element) (1f-45), and the DL assignment to the first cell or the second cell from the first cell is received. , it may be implicitly indicated. The beam alignment operation may be automatically driven before data transmission/reception when the second cell is configured or activated. In a situation where beam alignment is performed (1f-50), the UE drives the DRX operation for the second cell (1f-55). The beam alignment is stopped when a specific message is received from a specific cell or the second cell is deactivated or reset.

1G is a flowchart for explaining an operation of a terminal performing DRX in the present invention.

In step 1g-05, the UE establishes a connection with the first cell. In step 1g-10, the terminal establishes a connection with the second cell. In step 1g-15, the terminal is provided with DRX configuration information of the first cell and the second cell from the first cell. The DRX configuration information of the first cell and the second cell may be provided to the terminal at the same time or at different times. In step 1g-20, the UE drives the DRX operation for the first cell. In step 1g-25, the terminal receives a predetermined MAC CE. In step 1g-30, the terminal performs beam alignment with the second cell. In step 1g-35, the terminal drives the DRX operation for the second cell.

FIG. 1H is a diagram for explaining a process in which a UE transmits a Scheduling Request and receives radio resource allocation from a base station.

In step 1h-10, the UE (1h-00) generates a PDCP SDU to be transmitted. In step 1h-15, the terminal determines whether there is a radio resource to transmit the data. If there is no resource, it is determined whether a usable PUCCH is allocated. If the PUCCH exists, an SR is transmitted to the base station 1h-05 using the PUCCH. The base station that has successfully received this in step 1h-20 schedules a radio resource capable of transmitting a BSR (Buffer Status Report) to the terminal. The BSR is used to inform the base station how much data the terminal has. In step 1h-25, the terminal transmits the BSR by using the allocated radio resource. In step 1h-30, the base station allocates a radio resource capable of transmitting the PDCP SDU. In step 1h-35, the terminal transmits the data to the base station. In step 1h-40, the base station transmits ACK/NACK information for the data.

1I is a diagram for explaining a process of performing a scheduling request operation of a cell performing a beam-based operation in the present invention.

The UE establishes an RRC connection with the first cell (1i-05). A low frequency band is applied to the first cell, and beam alignment is not required using an omnidirectional or sector antenna. A carrier direct technique is configured for the purpose of improving peak throughput for the UE. To this end, the first cell exchanges configuration information with the second cell (1i-10), and adds the second cell as a serving cell of the terminal (1i-15). Since the second cell uses a high frequency band, a beam antenna is applied. In addition, the first cell transmits SR configuration information for the first cell to the terminal (1f-20). When the SR transmission condition is satisfied, the UE transmits the SR to the first cell (1i-25). After transmitting the SR, the terminal drives a beam alignment operation (1i-30). In response to the SR, the first cell or the second cell provides DL assignment to the UE (1i-35, 1i-40).

1J is a flowchart for explaining an operation of a terminal performing SR in the present invention.

In step 1j-05, the UE establishes a connection with the first cell. In step 1j-10, the terminal establishes a connection with the second cell. In step 1j-15, the terminal receives SR configuration information for the first cell from the first cell. In step 1j-20, the UE transmits an SR to the first cell. In step 1j-25, after the SR transmission, the UE performs beam alignment with the second cell, and monitors (PDCCH) whether DL assignment is received from the first cell or the second cell. In step 1j-30, the terminal receives the DL assignment from the first cell or the second cell.

1k shows the structure of the terminal.

Referring to the drawings, the terminal includes a radio frequency (RF) processing unit 1k-10, a baseband processing unit 1k-20, a storage unit 1k-30, and a control unit 1k-40. .

The RF processing unit 1k-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processing unit 1k-10 up-converts the baseband signal provided from the baseband processing unit 1k-20 into an RF band signal, transmits it through an antenna, and receives an RF band signal received through the antenna. down-converts to a baseband signal. For example, the RF processing unit 1k-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), and the like. can In the figure, only one antenna is shown, but the terminal may include a plurality of antennas. Also, the RF processing unit 1k-10 may include a plurality of RF chains. Furthermore, the RF processing unit 1k-10 may perform beamforming. For the beamforming, the RF processing unit 1k-10 may adjust the phase and magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. Also, the RF processing unit may perform MIMO, and may receive multiple layers when performing MIMO operation.

The baseband processing unit 1k-20 performs a function of converting between a baseband signal and a bit stream according to a physical layer standard of the system. For example, when transmitting data, the baseband processing unit 1k-20 generates complex symbols by encoding and modulating a transmitted bit stream. Also, when receiving data, the baseband processing unit 1k-20 restores a received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 1k-10. For example, in the case of orthogonal frequency division multiplexing (OFDM), when transmitting data, the baseband processing unit 1k-20 encodes and modulates a transmission bit stream to generate complex symbols, and convert the complex symbols to subcarriers. After mapping to , OFDM symbols are constructed through inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, upon data reception, the baseband processing unit 1k-20 divides the baseband signal provided from the RF processing unit 1k-10 into OFDM symbol units, and performs a fast Fourier transform (FFT) operation on subcarriers. After reconstructing the mapped signals, the received bit stream is reconstructed through demodulation and decoding.

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

The storage unit 1k-30 stores data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the storage unit 1k-30 may store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit 1k-30 provides stored data according to the request of the control unit 1k-40.

The controller 1k-40 controls overall operations of the terminal. For example, the control unit 1k-40 transmits and receives signals through the baseband processing unit 1k-20 and the RF processing unit 1k-10. In addition, the control unit 1k-40 writes and reads data in the storage unit 1k-40. To this end, the controller 1k-40 may include at least one processor. For example, the controller 1k-40 may include a communication processor (CP) that controls for communication and an application processor (AP) that controls an upper layer such as an application program.

11 illustrates a block configuration of a main base station in a wireless communication system according to an embodiment of the present invention.

As shown in the figure, the base station includes an RF processing unit 11-10, a baseband processing unit 11-20, a backhaul communication unit 11-30, a storage unit 11-40, and a control unit 11-50. is comprised of

The RF processing unit 11-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processor 11-10 up-converts the baseband signal provided from the baseband processor 11-20 into an RF band signal, transmits it through an antenna, and receives the RF band signal through the antenna. downconverted to a baseband signal. For example, the RF processing unit 11-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is shown in the drawing, the first access node may include a plurality of antennas. In addition, the RF processing unit 11-10 may include a plurality of RF chains. Furthermore, the RF processing unit 11-10 may perform beamforming. For the beamforming, the RF processing unit 11-10 may adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 11-20 performs a function of converting a baseband signal and a bit stream according to the physical layer standard of the first radio access technology. For example, when transmitting data, the baseband processing unit 11-20 generates complex symbols by encoding and modulating a transmitted bit stream. Also, upon data reception, the baseband processing unit 11-20 restores the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 11-10. For example, in the OFDM scheme, when transmitting data, the baseband processing unit 11-20 generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then IFFT OFDM symbols are constructed through operation and CP insertion. Also, upon data reception, the baseband processing unit 11-20 divides the baseband signal provided from the RF processing unit 11-10 into OFDM symbol units, and restores signals mapped to subcarriers through FFT operation. After that, the received bit stream is restored through demodulation and decoding. The baseband processing unit 11-20 and the RF processing unit 11-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 11-20 and the RF processing unit 11-10 may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

The backhaul communication unit 11-30 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 11-30 converts a bit string transmitted from the main station to another node, for example, an auxiliary base station, a core network, etc. into a physical signal, and converts the physical signal received from the other node into a bit convert to heat

The storage unit 11-40 stores data such as a basic program, an application program, and setting information for the operation of the main station. In particular, the storage unit 11-40 may store information on a bearer allocated to an accessed terminal, a measurement result reported from the accessed terminal, and the like. In addition, the storage unit 11-40 may store information serving as a criterion for determining whether to provide or stop multiple connections to the terminal. In addition, the storage unit 11-40 provides the stored data according to the request of the control unit 11-50.

The control unit 11-50 controls overall operations of the main station. For example, the control unit 11-50 transmits and receives signals through the baseband processing unit 11-20 and the RF processing unit 11-10 or through the backhaul communication unit 11-30. In addition, the control unit 11-50 writes and reads data in the storage unit 11-40. To this end, the control unit 11-50 may include at least one processor.

In HF, it may be necessary to perform beam alignment before Active Time starts.

Not needed in LF.

1. Indicate whether beam alignment is performed when setting

2. In case of LF-HF CA case, DRX is applied only to LF and HF remains off? When scheduling starts in LF, HF is also active time after beam alignment.

- Depending on whether HF beam alignment, inactivity timer, etc. is selectively driven

- When scheduling starts in LF, the UE reports whether HF beam alignment is

3. What is SR?

SR is set in LF, but it may be necessary to perform random access in HF for beam recovery

UE <-> gNB NR to RRC connection setup UE <- gNB At least one SCell configuration UE <- gNB DRX settings (inactivity timer, onDurationTimer, etc.)
Specific for each serving cell to which the DRX-related second operation is to be applied.
Hereinafter, it is considered that the second operation is not instructed for the first cell and the second operation is indicated for the second cell. UE Perform DRX operation
Apply the DRX second action to the serving cell to which the second action application is indicated
DRX first action applied to a serving cell for which application of the second action is not indicated
1st operation: PDCCH monitoring when onDurationTimer/inactivityTimer is driven.
Second operation: In the first phase, PDCCH monitoring when onDurationTimer/inactivityTimer is driven. In the second situation, PDCCH is not monitored even if onDurationTimer/inactivityTimer is driven
The first situation is a situation in which the base station recognizes the optimal beam to be transmitted to the terminal through the beam alignment process and the terminal recognizes the optimal beam to receive from the base station
The second situation is a state in which beam alignment is not performed. UE <- gNB DL assignment received through the first cell. If the MAC CE indicating to perform beam alignment in the second cell is included, the random access procedure is started in the second cell. And PDCCH monitoring is started in the second cell as well.

<Second embodiment> FIG. 2A is a diagram showing the structure of a next-generation mobile communication system.

Referring to FIG. 2A, as shown, the radio access network of the next-generation mobile communication system includes a next-generation base station (New Radio Node B, hereinafter NR NB) (2a-10) and NR CN (2a-05, New Radio Core Network). is composed A user terminal (New Radio User Equipment, hereinafter NR UE or terminal) 2a-15 accesses an external network through NR NBs 2a-10 and NR CNs 2a-05.

In FIG. 2A , NR NBs 2a-10 correspond to an Evolved Node B (eNB) of an existing LTE system. The NR NB is connected to the NR UE 2a-15 through a radio channel and can provide a service superior to that of the existing Node B. In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device for scheduling by collecting status information such as buffer status, available transmission power status, and channel status of UEs is required. (2a-10) is in charge. One NR NB typically controls multiple cells. In order to implement ultra-high-speed data transmission compared to existing LTE, it can have more than the existing maximum bandwidth, and additional beamforming technology can be grafted by using Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a radio access technology. . In addition, an Adaptive Modulation & Coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel state of the terminal is applied. The NR CN (2a-05) performs functions such as mobility support, bearer setup, QoS setup, and the like. NR CN is a device in charge of various control functions as well as mobility management functions for the terminal and is connected to a number of base stations. In addition, the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN is connected to the MME (2a-25) through a network interface. The MME is connected to the existing base station eNB (2a-30).

2B is a diagram for explaining a method of determining whether access is granted in the existing LTE system.

The inside of the LTE terminal is divided into AS (2b-15, Access Stratum) and NAS (2b-05, Non Access Stratum) by function. AS performs all functions related to access, and NAS performs functions not related to access, such as PLMN selection and service request. Whether access is possible is mainly performed in the terminal AS. As mentioned above, the network can restrict new access when the network is congested. To this end, the network broadcasts related configuration information so that each terminal can determine whether access is possible (2b-35). In the existing LTE system, as new requirements are added, a new barring mechanism has been proposed accordingly, and as a result, a plurality of access barring checks are performed. When the terminal NAS transmits the service request (2b-10) to the terminal AS, the terminal AS checks whether access to the network can be actually performed or not in response to the request. When the establishment cause value of the service request is delay tolerant access, the terminal AS first performs EAB (2b-20, Extended Access Barring). The EAB barring mechanism is an access check process that is applied only to MTC (Machine Type Communication). If the EAB is passed, the terminal AS performs ACDC (2b-20, Application specific Congestion control for Data Communication). An application requesting a service is given one piece of ACDC category information, and the ACDC category value may be included in the service request and provided to the terminal AS. The network may provide barring configuration information for each ACDC category. That is, the access check process may be performed for each application group classified into the ACDC category. If the barring configuration information for the ACDC category is not provided from the network, the terminal AS omits the ACDC access check process. When passing through ACDC, the terminal AS performs ACB (2b-30, Access Class Barring). The ACB performs an access check process using mobile originating (MO) data or separately provided barring configuration information according to MO signaling. The MMTEL voice/video/SMS may omit the ACB performing process by using the ACB skip indicator (2b-25). If it is determined in the process of the above-mentioned plurality of access checks that access is all possible, then, the terminal AS may attempt to access the network. That is, the terminal AS performs random access and transmits an RRC connection request message (2b-40) to the base station. There is also an access check process that is not performed by the terminal AS. When the terminal AS receives barring configuration information (2b-45, SSAC) for MMTEL voice/video from the network, it delivers it to the IMS layer (2b-50) in the terminal managing the service. Upon receiving the barring configuration information, the IMS layer performs an access check process when the service is triggered. When SSAC was introduced, the terminal AS was designed to perform functions regardless of the type of application or service. Therefore, in order to control whether or not to grant access to only a specific service such as MMTEL voice/video, barring configuration information is directly delivered to the layer managing the service, and the layer performs an access check process.

2C is a diagram for explaining a wireless connection state transition in a next-generation mobile communication system.

The next-generation mobile communication system has three radio access states (RRC states). The connected mode (RRC_CONNECTED, 2c-05) is a wireless connection state in which the terminal can transmit and receive data. The standby mode (RRC_IDLE, 2c-30) is a radio access state in which the terminal monitors whether paging is transmitted to itself. The two modes are radio access states that are also applied to the existing LTE system, and the detailed technology is the same as that of the existing LTE system. In the next-generation mobile communication system, the RRC_INACTIVE radio connection state (2c-15) is newly defined. In the radio access state, the UE context is maintained in the base station and the terminal, and RAN-based paging is supported. The characteristics of the new wireless connection state are listed below.

- Cell re-selection mobility;

- CN - NR RAN connection (both C/U-planes) has been established for UE;

- The UE AS context is stored in at least one gNB and the UE;

- Paging is initiated by NR RAN;

- RAN-based notification area is managed by NR RAN;

- NR RAN knows the RAN-based notification area which the UE belongs to;

The new INACTIVE radio access state may transition to a connected mode or a standby mode using a specific procedure. It is converted from INACTIVE mode to connected mode according to connection activation, and it is converted from connected mode to INACTIVE mode using the connection inactivation procedure (2c-10). The connection activation/inactivation procedure is characterized in that one or more RRC messages are transmitted and received between the terminal and the base station, and consists of one or more steps. It is also possible to switch from INACTIVE mode to standby mode according to a specific procedure (2c-20). As the specific procedure mentioned above, various methods such as specific message exchange or timer-based or event-based may be considered. Switching between connected mode and standby mode follows the existing LTE technology. That is, the mode is switched through a connection establishment or release procedure (2c-25).

2D is a diagram for explaining a process of performing an access connection in an RRC INACTIVE state in the present invention.

The UE AS (2d-10) is provided with barring configuration information to be applied in the standby mode through system information from the base station (2d-15) (2d-20). The barring configuration information is used so that the terminal can determine whether to access access by category. One Category is at least one or a plurality of Access Class, UE type (UE/device type), service type, call type, application type, and control signal type (signalling type). It is decided to correspond one-to-one with the combination. The base station provides barring configuration information for each category to the terminal, and stores the UE AS. For specific services such as emergency, voice call, video call, and text message service, even if barring setting information is not provided in the system information, it may have a default value in the terminal. If, for the specific service, barring configuration information is provided as the system information, it is applied with priority over the default value. The UE NAS 2d-05 determines which of the elements the access to be attempted corresponds to, and maps an appropriate category to the access. Then, the UE NAS transmits a service request for the access to the UE AS along with the mapped category (2d-25). In the case of Emergency, the UE NAS may notify that the service request is emergency-related in the form of a call, without notifying the UE AS of category information. The UE AS checks the stored barring configuration information corresponding to the category received from the UE NAS with respect to the service request. It is determined whether access is permitted for the access by using the barring configuration information (2d-30). If allowed, an RRC connection with the base station is attempted (2d-35). The base station and the terminal perform data transmission/reception (2d-37). If necessary, the base station may switch the terminal to the RRC INACTIVE state. To this end, the base station switches the terminal from the connected mode to the INACTIVE mode through a connection inactivation procedure (2d-40). In this case, the base station provides DRB-based barring configuration information to the terminal. This is used when the terminal determines whether to allow access for the access (2d-45) generated in the INACTIVE state. The reason for providing the DRB-based barring configuration information is that in the INACTIVE state, the UE context (2d-50) for the terminal is still stored in the base station and the terminal. This is in contrast to the deletion of the UE context when switching from the connected mode to the standby mode. The UE context information includes all configuration information necessary for the UE to transmit and receive data in the connected mode. Therefore, it is possible to provide barring configuration information based on DRB in the INACTIVE state. For a specific service, the DRB-based barring configuration information may collide with the barring configuration information provided from the system information, and in this case, the DRB-based barring configuration information is applied. Whether to allow access to an access to which DRB-based barring configuration information is not applied is determined by applying category-based barring information provided from the system information (2d-55). For example, the RRC signaling generated in the INACTIVE mode determines whether to allow access by using barring configuration information for a category corresponding to the RRC signaling.

2E is a diagram for explaining the operation of the terminal AS performing access connection in the RRC INACTIVE state in the present invention.

In step 2e-05, the UE AS receives barring configuration information for each category provided by broadcasting or dedicated signaling from the base station. In step 2e-10, the UE AS receives a service request along with category information from the UE NAS. In step 2e-15, the UE AS determines whether access to the service request is permitted by using barring configuration information corresponding to the category. If the access is allowed in step 2e-20, the terminal performs an establishment procedure with the base station. Through this, it is switched to the RRC connected mode. In step 2e-25, the UE AS receives a message related to the connection inactivation procedure for switching the INACTIVE mode from the base station. The message includes DRB-based barring configuration information. In step 2e-30, the UE AS switches from the connected mode to the INACTIVE mode. In step 2e-35, the UE AS access is triggered. In step 2e-40, the UE AS determines whether access to the access is permitted by using the DRB-based barring configuration information.

Figure 2f shows the structure of the terminal.

Referring to the drawings, the terminal includes a radio frequency (RF) processing unit 2f-10, a baseband processing unit 2f-20, a storage unit 2f-30, and a control unit 2f-40. .

The RF processing unit 2f-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processing unit 2f-10 up-converts the baseband signal provided from the baseband processing unit 2f-20 into an RF band signal, transmits it through an antenna, and receives an RF band signal received through the antenna. down-converts to a baseband signal. For example, the RF processing unit 2f-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), and the like. can In the figure, only one antenna is shown, but the terminal may include a plurality of antennas. Also, the RF processing unit 2f-10 may include a plurality of RF chains. Furthermore, the RF processing unit 2f-10 may perform beamforming. For the beamforming, the RF processing unit 2f-10 may adjust the phase and magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. Also, the RF processing unit may perform MIMO, and may receive multiple layers when performing MIMO operation.

The baseband processing unit 2f-20 performs a function of converting between a baseband signal and a bit stream according to a physical layer standard of the system. For example, when transmitting data, the baseband processing unit 2f-20 generates complex symbols by encoding and modulating the transmitted bit stream. Also, when receiving data, the baseband processing unit 2f-20 restores the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 2f-10. For example, in the case of orthogonal frequency division multiplexing (OFDM), when transmitting data, the baseband processing unit 2f-20 encodes and modulates a transmission bit stream to generate complex symbols, and convert the complex symbols to subcarriers. After mapping to , OFDM symbols are constructed through inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, upon data reception, the baseband processing unit 2f-20 divides the baseband signal provided from the RF processing unit 2f-10 into OFDM symbol units, and sends them to subcarriers through a fast Fourier transform (FFT) operation. After reconstructing the mapped signals, the received bit stream is reconstructed through demodulation and decoding.

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

The storage unit 2f-30 stores data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the storage unit 2f-30 may store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit 2f-30 provides stored data according to the request of the control unit 2f-40.

The controller 2f-40 controls overall operations of the terminal. For example, the control unit 2f-40 transmits and receives signals through the baseband processing unit 2f-20 and the RF processing unit 2f-10. In addition, the control unit 2f-40 writes and reads data in the storage unit 2f-40. To this end, the controller 2f-40 may include at least one processor. For example, the controller 2f-40 may include a communication processor (CP) that controls for communication and an application processor (AP) that controls an upper layer such as an application program.

2G illustrates a block configuration of a main base station in a wireless communication system according to an embodiment of the present invention.

As shown in the figure, the base station includes an RF processing unit (2g-10), a baseband processing unit (2g-20), a backhaul communication unit (2g-30), a storage unit (2g-40), and a control unit (2g-50). is comprised of

The RF processing unit 2g-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processor 2g-10 up-converts the baseband signal provided from the baseband processor 2g-20 into an RF band signal, transmits it through an antenna, and receives the RF band signal through the antenna. downconverted to a baseband signal. For example, the RF processing unit 2g-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is shown in the drawing, the first access node may include a plurality of antennas. Also, the RF processing unit 2g-10 may include a plurality of RF chains. Furthermore, the RF processing unit 2g-10 may perform beamforming. For the beamforming, the RF processing unit 2g-10 may adjust the phase and magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 2g-20 performs a function of converting a baseband signal and a bit stream according to the physical layer standard of the first radio access technology. For example, when transmitting data, the baseband processing unit 2g-20 generates complex symbols by encoding and modulating a transmitted bit stream. In addition, when receiving data, the baseband processing unit 2g-20 restores the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 2g-10. For example, in the OFDM scheme, when transmitting data, the baseband processing unit 2g-20 generates complex symbols by encoding and modulating a transmitted bit stream, maps the complex symbols to subcarriers, and then IFFT OFDM symbols are constructed through operation and CP insertion. Also, upon data reception, the baseband processing unit 2g-20 divides the baseband signal provided from the RF processing unit 2g-10 into OFDM symbol units, and restores signals mapped to subcarriers through FFT operation. After that, the received bit stream is restored through demodulation and decoding. The baseband processing unit 2g-20 and the RF processing unit 2g-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 2g-20 and the RF processing unit 2g-10 may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

The backhaul communication unit 2g-30 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 2g-30 converts a bit string transmitted from the main station to another node, for example, an auxiliary base station, a core network, etc. into a physical signal, and converts the physical signal received from the other node into a bit convert to heat

The storage unit 2g-40 stores data such as a basic program, an application program, and setting information for the operation of the main station. In particular, the storage unit 2g-40 may store information on a bearer assigned to an accessed terminal, a measurement result reported from the accessed terminal, and the like. In addition, the storage unit 2g-40 may store information serving as a criterion for determining whether to provide or stop multiple connections to the terminal. In addition, the storage unit 2g-40 provides the stored data according to the request of the control unit 2g-50.

The controller 2g-50 controls overall operations of the main station. For example, the control unit 2g-50 transmits and receives signals through the baseband processing unit 2g-20 and the RF processing unit 2g-10 or through the backhaul communication unit 2g-30. In addition, the control unit 2g-50 writes and reads data in the storage unit 2g-40. To this end, the controller 2g-50 may include at least one processor.

LTE access control mechanism [1]:

Access class barring features has been discussed RAN2 (and SA1) in almost every release since Rel-8. As a result, there are multiple access barring mechanisms in LTE:

1. Access Class barring ( ACB ) as per Rel-8: In this mechanism, it is possible to bar the UE. Normal UEs (Access Class 0-9) are barred with a probability factor and a timer whereas special classes can be controlled separately. Also emergency calls can be controlled separately.

SEQUENCE {

ac-BarringInfo SEQUENCE {

ac-BarringForEmergency BOOLEAN,

ac-BarringForMO-Signalling AC-BarringConfig OPTIONAL, -- Need OP

ac-BarringForMO-Data AC-BarringConfig OPTIONAL -- Need OP

AC-BarringConfig ::= SEQUENCE {

ac-BarringFactor ENUMERATED {

p00, p05, p10, p15, p20, p25, p30, p40,

p50, p60, p70, p75, p80, p85, p90, p95},

ac-BarringTime ENUMERATED {s4, s8, s16, s32, s64, s128, s256, s512},

ac-BarringForSpecialAC BIT STRING (SIZE(5))

}

2. Service Specific Access Control ( SSAC ): Allows the network to prohibit MMTel-voice and MMTel-video accesses. The network broadcasts barring parameters (parameters similar to ACB) and the actual barring algorithm is similar to ACB (barring factor and random timer). The actual decision if access is allowed is done in the IMS layer of the UE.

[[ ssac-BarringForMMTEL-Voice-r9 AC-BarringConfig OPTIONAL, -- Need OP

ssac-BarringForMMTEL-Video-r9 AC-BarringConfig OPTIONAL -- Need OP

3. Access control for CS fall-back: Allows the network to prohibit CSFB users. The actual barring algorithm is similar to ACB.

]],

[[ ac-BarringForCSFB-r10 AC-BarringConfig OPTIONAL -- Need OP

]],

4. Extended Access Barring ( EAB ): Allows the network to prohibit low priority UEs. Barring is based on a bitmap in which each access class (AC 0-9) can be either barred or allowed.

SystemInformationBlockType14-r11 ::= SEQUENCE {

eab-Param-r11 CHOICE {

eab-Common-r11 EAB-Config-r11,

eab-PerPLMN-List-r11 SEQUENCE (SIZE (1..maxPLMN-r11)) OF EAB-ConfigPLMN-r11

} OPTIONAL, -- Need OR

lateNonCriticalExtension OCTET STRING OPTIONAL,

...

EAB-Config-r11 ::= SEQUENCE {

eab-Category-r11 ENUMERATED {a, b, c},

eab-BarringBitmap-r11 BIT STRING (SIZE (10))

}

5. Access class barring bypass: Allows omitting access class barring for IMS voice and video users.

[[ ac-BarringSkipForMMTELVoice-r12 ENUMERATED {true} OPTIONAL, -- Need OP

ac-BarringSkipForMMTELVideo-r12 ENUMERATED {true} OPTIONAL, -- Need OP

ac-BarringSkipForSMS-r12 ENUMERATED {true} OPTIONAL, -- Need OP

6. Application Specific Access Class (ACDC) barring: Allows to bar traffic of certain application. In this solution, applications are categorized based on global application ID (in Android or IOS). The network broadcasts barring parameters (barring factor and timer) for each category.

]],

[[ acdc-BarringForCommon-r13 ACDC-BarringForCommon-r13 OPTIONAL, -- Need OP

acdc-BarringPerPLMN-List-r13 ACDC-BarringPerPLMN-List-r13 OPTIONAL -- Need OP

]],

ACDC-BarringForCommon-r13 ::= SEQUENCE {

acdc-HPLMNonly-r13 BOOLEAN,

barringPerACDC-CategoryList-r13 BarringPerACDC-CategoryList-r13

}

ACDC-BarringPerPLMN-List-r13 ::= SEQUENCE (SIZE (1.. maxPLMN-r11)) OF ACDC-BarringPerPLMN-r13

ACDC-BarringPerPLMN-r13 ::= SEQUENCE {

plmn-IdentityIndex-r13 INTEGER (1..maxPLMN-r11),

adc-OnlyForHPLMN-r13 BOOLEAN,

barringPerACDC-CategoryList-r13 BarringPerACDC-CategoryList-r13

}

BarringPerACDC-Category-r13 ::= SEQUENCE {

adc-Category-r13 INTEGER (1..maxACDC-Cat-r13),

adc-BarringConfig-r13 SEQUENCE {

ac-BarringFactor-r13 ENUMERATED {

p00, p05, p10, p15, p20, p25, p30, p40,

p50, p60, p70, p75, p80, p85, p90, p95},

ac-BarringTime-r13 ENUMERATED {s4, s8, s16, s32, s64, s128, s256, s512}

} OPTIONAL -- Need OP

}

Any overload control mechanism need to consider multiple sometimes conflicting requirements at congestion:

Observation:

NAS-AS interaction is required, and there seems to be no AS based triggering.

That is, there is no access control mechanism that controls whether data generated by the AS is transmitted.

Because these things can be controlled by scheduling

If so, there is no need to focus on the integration of the mechanisms listed above in NR and introduce AS based triggering anew.

However, access control is required for the INACTIVE state terminal.

If so, it seems to be a method for the base station to provide ACDC parameters for each DRB when the terminal transitions to the INACTIVE state.

And improved ACDC design

AC-config does not distinguish the default AC (0 to 9).

The following traffic can be treated separately through AC control. (bypass AC)

- emergency

- MMTELVoice

- MMTELVideo

- SMS

Through AC control, the following traffics can be controlled probabilistically regardless of user class.

- MO-Signalling

- MO-Data

- MMTEL-Voice

- MMTEL-Video

- CSFB

Delay tolerant traffic can be turned on/off for each AC

NR unified access control:

ACDC based

The default ACDC for a specific traffic (emergency call) is the highest category

ACDC of specific traffic can be broadcast as system information (MMTEL voice, MMTEL video, MMTEL-SMS). The broadcast value overriding the terminal dedicate value.

Basically, when RRC connection is established, the NAS notifies the ACDC category to the AS.

During RRC connection suspension, the NAS notifies the AS of the ACDC category for each DRB.

Emergency no NAS configuration of category (that is, the NAS does not notify the category information separately and only informs that the call type is emergency)
default = highest category (no barring)
Separate category can be set for each cell in system information
The value set for each cell takes precedence over the default value. Certain Application (Voice, Video, SMS,...) The categories are configured on the NAS.
You can set a separate category for each cell in system information (or you can set whether to apply the highest category)
The value set for each cell takes precedence over the value set on the NAS. MO-signaling/MO-data/delay tolerant traffic The categories are configured on the NAS.
When the NAS informs the AS of the category, the AS performs AC with the configured category. RRC signaling in INACTIVE state Either use the MO-signaling category, or do not apply AC to RRC messages. MO data in INACTIVE state The base station designates a category to be applied for each DRB when the terminal transitions to INACTIVE STATE.
Using the above categories, determine whether to RESUME

]], [[ acdc-BarringForCommon-r13 ACDC-BarringForCommon-r13 OPTIONAL, -- Need OP

acdc-BarringPerPLMN-List-r13 ACDC-BarringPerPLMN-List-r13 OPTIONAL -- Need OP

]],

ACDC-BarringForCommon-r13 ::= SEQUENCE {

acdc-HPLMNonly-r13 BOOLEAN,

barringPerACDC-CategoryList-r13 BarringPerACDC-CategoryList-r13

}

ACDC-BarringPerPLMN-List-r13 ::= SEQUENCE (SIZE (1.. maxPLMN-r11)) OF ACDC-BarringPerPLMN-r13

ACDC-BarringPerPLMN-r13 ::= SEQUENCE {

plmn-IdentityIndex-r13 INTEGER (1..maxPLMN-r11),

adc-OnlyForHPLMN-r13 BOOLEAN,

barringPerACDC-CategoryList-r13 BarringPerACDC-CategoryList-r13

}

BarringPerACDC-Category-r13 ::= SEQUENCE {

adc-Category-r13 INTEGER (1..maxACDC-Cat-r13),

adc-BarringConfig-r13 SEQUENCE {

ac-BarringFactor-r13 ENUMERATED {

p00, p05, p10, p15, p20, p25, p30, p40,

p50, p60, p70, p75, p80, p85, p90, p95},

ac-BarringTime-r13 ENUMERATED {s4, s8, s16, s32, s64, s128, s256, s512}

} OPTIONAL -- Need OP

}

<Third embodiment>

3A is a diagram illustrating the structure of an LTE system to be referred to for the description of the present invention.

Referring to FIG. 3A, the wireless communication system includes a plurality of base stations 3a-05, 3a-10, 3a-15, 3a-20, and a Mobility Management Entity (MME) 3a-20 and S It consists of -GW (Serving-Gateway) (3a-30). User equipment (hereinafter referred to as UE or terminal) 3a-35 is external through base station 3a-05, 3a-10, 3a-15, 3a-20 and S-GW 3a-30. connect to the network

The base stations 3a-05, 3a-10, 3a-15, and 3a-20 are access nodes of a cellular network and provide wireless access to terminals accessing the network. That is, the base stations 3a-05, 3a-10, 3a-15, and 3a-20 collect status information such as buffer status, available transmission power status, and channel status of terminals in order to service users' traffic. Thus, the scheduling is performed to support the connection between the terminals and a core network (CN). The MME 3a-25 is a device in charge of various control functions as well as a mobility management function for the UE, and is connected to a plurality of base stations, and the S-GW 3a-30 is a device that provides a data bearer. In addition, the MME (3a-25) and the S-GW (3a-30) may further perform authentication (authentication), bearer management, etc. for the terminal accessing the network, and the base station (3a-05) (3a-10) Processes packets arriving from (3a-15) (3a-20) or packets to be delivered to the base station (3a-05) (3a-10) (3a-15) (3a-20).

3B is a diagram illustrating a radio protocol structure of an LTE system to be referred to for the description of the present invention. Although the NR to be defined in the future may be different from the radio protocol structure in this drawing, it will be described for convenience of description of the present invention.

Referring to Figure 3b, the radio protocol of the LTE system is PDCP (Packet Data Convergence Protocol) (3b-05) (3b-40), RLC (Radio Link Control) (3b-10) (3b-35 in the UE and ENB, respectively) ) and MAC (Medium Access Control) (3b-15) (3b-30). PDCP (Packet Data Convergence Protocol) (3b-05) (3b-40) is in charge of operations such as IP header compression/restore, and radio link control (Radio Link Control, hereinafter referred to as RLC) (3b-10) (3b) -35) reconfigures the PDCP PDU (Packet Data Unit) to an appropriate size. The MACs 3b-15 and 3b-30 are connected to several RLC layer devices configured in one terminal, and perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The physical layer (3b-20) (3b-25) channel-codes and modulates upper layer data, creates an OFDM symbol and transmits it over a radio channel, or demodulates and channel-decodes an OFDM symbol received through the radio channel to a higher layer. transfer action. In addition, the physical layer uses Hybrid ARQ (HARQ) for additional error correction, and the receiving end transmits whether a packet transmitted from the transmitting end is received with 1 bit. This is called HARQ ACK/NACK information. Downlink HARQ ACK/NACK information for uplink transmission is transmitted through a Physical Hybrid-ARQ Indicator Channel (PHICH) physical channel, and uplink HARQ ACK/NACK information for downlink transmission is PUCCH (Physical Uplink Control Channel) or PUSCH (Physical Uplink Shared Channel) It may be transmitted through a physical channel.

Although not shown in this figure, an RRC (Radio Resource Control, hereinafter referred to as RRC) layer exists above the PDCP layer of the terminal and the base station, and the RRC layer provides access and measurement related configuration control messages for radio resource control. can give and receive For example, the UE may be instructed to measure by using the message of the RRC layer, and the UE may report the measurement result to the base station using the message of the RRC layer.

3C is a diagram illustrating a message flow between a terminal and a base station when using the first method for inter-cell handover proposed by the present invention. This example drawing may be applied, for example, when handover from an NR cell to an LTE cell is performed.

In FIG. 3c , the terminal 3c-01 in the dormant mode (RRC_IDLE) accesses the base station for reasons such as generation of data to be transmitted (3c-11). In the sleep mode, data cannot be transmitted because the terminal is not connected to the network for power saving, etc., and a transition to the connected mode (RRC_CONNECTED) is required for data transmission. If the terminal succeeds in the access procedure to the base station 3c-03, the terminal changes its state to the connected mode (RRC_CONNECTED), and the terminal in the connected mode can transmit and receive data with the base station (3c-13).

Thereafter, the base station determines the signal strength of the current base station (serving cell) and neighboring base stations of the corresponding terminal through a method such as receiving the measurement report (3c-15) set to the terminal, and the terminal moves to another base station Decide whether to do (ie handover) or not (3c-17). If the base station decides to handover the terminal to another base station (eg, (3c-05)), it transmits a handover request message to the corresponding base station to request a handover (3c-19), and a response message It is determined whether or not handover is possible by receiving ? (3c-21).

Accordingly, the source base station 3c-03 transmits a handover command to the terminal 3c-01 (3c-23). Upon receiving the handover command, the terminal synchronizes with the target base station through reception of a reference signal or synchronization signal (3c-25) (3c-27) transmitted from the target (target) base station 3c-05. carry out the process In addition, the second layer (eg, MAC layer) of the terminal is initialized (3c-31), and the configuration information related to the first layer (eg, physical layer) received from the handover command is applied (3c-33) ). Meanwhile, an encryption key to be used in the target base station is generated, and additionally generated keys from the generated key are applied to future communication (3c-35). Accordingly, a response message to the handover command message is generated, and encryption and integrity check codes are added to the additionally generated additional keys, and then transmitted to lower layers (ie, MAC and physical layers). Accordingly, the MAC layer of the terminal performs random access to the target base station, receives uplink synchronization and uplink resource allocation, and transmits the generated handover completion message (3c-41). The random access refers to transmitting a specially designed preamble to a predetermined resource of a base station, receiving a random access response from the base station, and receiving and sending uplink synchronization and uplink resource allocation. It means a series of processes such as sending a desired message. When the random access operation is successfully completed, the terminal may transmit a channel quality report through a predetermined channel (eg, PUCCH) according to the physical layer setting in the target base station included in the handover command, and , can receive a system information block (SIB) that has not been obtained, and then the terminal can transmit and receive data to and from the corresponding base station as the corresponding target base station becomes a serving base station.

3D is a diagram illustrating an operation sequence of a UE when using the first method for inter-cell handover proposed by the present invention. This example drawing may be applied, for example, when handover from an NR cell to an LTE cell is performed.

In FIG. 3d , it is assumed that the terminal is already in the connected mode (RRC_CONNECTED) and data transmission/reception is possible with the base station (3d-01). Although omitted in this figure, the terminal may have reported the measurement results of the current serving base station and the neighboring base station to the base station, and accordingly, the terminal receives a handover command from the base station (3d-03). Upon receiving the handover command, the terminal performs a synchronization process with the corresponding target base station through reception of a reference signal transmitted from the target (target) base station (3d-05). In addition, the second layer (eg, MAC layer) of the terminal is initialized (3d-07), and the configuration information related to the first layer (eg, physical layer) received from the handover command is applied (3d-09) ). Meanwhile, an encryption key to be used in the target base station is generated, and additionally generated keys from the generated key are applied to future communication (3d-11). Accordingly, a response message (eg, Reconfiguration complete message) to the handover command message is generated, the message is encrypted with the additionally generated additional keys, and an integrity check code is added to the lower layer (ie, MAC and physical layer) (3d-13). Accordingly, the MAC layer of the terminal performs random access to the target base station, receives uplink synchronization and uplink resource allocation, and transmits the generated handover completion message. When the random access operation is successfully completed (3d-15), the terminal sends a channel quality report, etc. to a predetermined channel (eg, PUCCH) according to the physical layer setting in the target base station included in the handover command. can be transmitted through (3d-17), and can receive a system information block (SIB) that has not been obtained (3d-19), after which the terminal becomes the serving base station and performs data transmission/reception with the corresponding base station can do.

3E is a diagram illustrating a message flow between a terminal and a base station when the second method of inter-cell handover proposed in the present invention is used. This example diagram shows, for example, handover from LTE cell to NR cell, handover from NR cell to NR cell, or handover from NR cell to LTE cell supporting MBB, RACH-less HO, conditional HO, etc. to be described later. It can be applied when performing over.

In FIG. 3E , the terminal 3e-01 in the sleep mode (RRC_IDLE) accesses the base station for reasons such as generation of data to be transmitted (3e-11). In the sleep mode, data cannot be transmitted because the terminal is not connected to the network for power saving, etc., and a transition to the connected mode (RRC_CONNECTED) is required for data transmission. When the terminal succeeds in the access procedure to the base station 3e-03, the terminal changes its state to the connected mode (RRC_CONNECTED), and the terminal in the connected mode can transmit and receive data with the base station (3e-13).

Thereafter, the base station determines the signal strength of the current base station (serving cell) and neighboring base stations of the corresponding terminal through a method such as receiving the measurement report (3e-15) set to the terminal, and the terminal moves to another base station Determine whether it should be done (ie, handover) (3e-17). If the base station decides to handover the terminal to another base station (eg, (3e-05)), it transmits a handover request message to the corresponding base station to request a handover (3e-19), and a response message It is determined whether or not handover is possible by receiving a (3e-21).

Accordingly, the source base station 3e-03 transmits a handover command to the terminal 3e-01 (3e-23). At this time, in the handover command message, Make-Before-Break HO (MBB; first HO) and/or UE-based HO (or conditional HO, second HO) may be indicated, and RACH-less HO is indicated. and beam information from the target base station, more specifically, single beam or multi-beam information may be included.

The Make-Before-Break HO refers to a technique for performing a handover operation immediately after receiving a handover command, but continuously transmitting and receiving data with a source cell. In addition, the UE-based HO does not immediately perform a handover operation even after receiving a handover command, and a predetermined handover condition (eg, a value set by the signal strength of the target base station) included in the handover command message. above) is satisfied, the UE determines the handover time. The RACH-less HO indicates that the target base station does not perform random access. For example, when the size of the target cell is small or the cell size of the source cell is similar, a method of omitting uplink synchronization may be used.

If the above Make-Before-Break HO (MBB; 1st HO) and/or UE-based HO (or conditional HO, 2nd HO) is indicated, the UE meets the handover ready condition Data transmission/reception is maintained at the source base station until the The handover preparation condition means a point in time when the first uplink transmission is possible in the destination base station if the Make-Before-Break HO is set, and if the UE-based HO is set, it is indicated in the handover command It means a case in which a predetermined handover condition is satisfied. In addition, when the Make-Before-Break HO and the UE-based HO are configured at the same time, a time when the first uplink transmission is possible in the target base station may be used as in the case where the Make-Before-Break HO is configured. (That is, even when a predetermined handover condition indicated in the handover command is met, the target base station can continue to communicate with the source base station until the first uplink transmission becomes possible.)

Upon receiving the Make-Before-Break HO, the terminal receiving the handover command immediately receives the UE-based HO command, and when a predetermined condition included in the handover command is satisfied, the target (target) base station A synchronization process with a corresponding target base station is performed through reception of a reference signal or synchronization signal (3e-29) (3e-31) transmitted from (3e-05) (3e-33). In addition, the second layer (eg, the MAC layer) of the terminal is initialized (3e-35), and the configuration information related to the first layer (eg, the physical layer) received from the handover command is applied (3e-37). ). Meanwhile, an encryption key to be used in the target base station is generated, and additionally generated keys from the generated key are applied to future communication (3e-39). Accordingly, a response message to the handover command message is generated, and encryption and integrity check codes are added to the additionally generated additional keys, and then transmitted to lower layers (ie, MAC and physical layers) (3e-41).

If RACH-less HO is not indicated in the handover command message, the terminal initiates random access to the target base station (3e-43). In this case, if the target base station is a cell configured with one beam, a first random access procedure is performed, and if the target base station is a cell configured with a plurality of beams, a second random access procedure is performed. Currently, low-frequency cells are mostly composed of a single beam, but the NR system can operate at high frequencies (eg, several tens of GHz). and a cell composed of a plurality of beams used can be used.

In the first random access procedure, the UE transmits a preamble, receives a response message (RAR) from the base station, transmits message 3 (eg, HO complete message), and receives the identifier (C-RNTI) of the UE in the PDCCH. made by the procedure. In the RAR message, transmission resource information for transmitting the message 3 is accommodated, and when the message 3 is transmitted, the UE transmits the message without applying beamforming, and receives the handover command, the identifier of the UE to be used by the target base station (C -RNTI) contains all or part of the C-RNTI MAC CE and RRC connection reconfiguration complete message including information.

In the second random access procedure, the UE transmits a preamble, receives a response message (RAR) from the base station, transmits message 3 (eg, HO complete message), and receives the identifier (C-RNTI) of the UE in the PDCCH. is made of In this case, when transmitting the preamble, it is assumed that the UE transmits a plurality of the same preamble to the base station using beams in different directions, and accordingly, the RAR message includes transmission resource information for message 3 transmission and the preamble Accommodates beam identifier information of one terminal, and when transmitting message 3, the terminal transmits message 3 using the corresponding beam according to the received RAR information (that is, by applying beamforming), and the message 3 is the hand The C-RNTI MAC CE including the terminal identifier (C-RNTI) information to be used by the target base station received in the over command and the best downlink transmission beam information among multiple beams of the base station (for example, the identifier or beam of the synchronization reference signal) index information) and all or part of the RRC connection reconfiguration complete message.

According to the above procedure (that is, the first random access procedure or the second random access procedure), the MAC layer of the terminal performs the random access to the target base station to receive uplink synchronization and uplink resource allocation, When the generated handover completion message is transmitted in message 3 (3e-45), and then the PDCCH addressed to the C-RNTI is received in the target cell (that is, when the random access is successfully completed), the handover is successful judged to have been carried out with

On the other hand, if the RACH-less HO is indicated in the handover command message, if the UE receives the PDCCH addressed to the C-RNTI in the target cell without transmitting the preamble, it is determined that the handover has been successfully performed.

When it is determined that the handover has been successfully performed as described above, the terminal transmits a channel quality report through a predetermined channel (eg, PUCCH) according to the physical layer setting in the target base station included in the handover command. (3e-47), and can receive a system information block (SIB) that has not been obtained (3e-49), and after that, the terminal becomes the serving base station and transmits and receives data with the corresponding base station. can be done

3F is a diagram illustrating an operation sequence of a terminal when using the second method of inter-cell handover proposed by the present invention. This example diagram shows, for example, handover from LTE cell to NR cell, handover from NR cell to NR cell, or handover from NR cell to LTE cell supporting MBB, RACH-less HO, conditional HO, etc. to be described later. It can be applied when performing over.

In FIG. 3f , it is assumed that the terminal is already in the connected mode (RRC_CONNECTED) and data transmission/reception is possible with the base station (3f-01). Although omitted in this figure, the terminal may have reported the measurement results of the current serving base station and the neighboring base station to the base station, and accordingly, the terminal receives a handover command from the base station (3f-03). At this time, in the handover command message, Make-Before-Break HO (MBB; first HO) and/or UE-based HO (or conditional HO, second HO) may be indicated, and RACH-less HO is indicated. and beam information from the target base station, more specifically, single beam or multi-beam information may be included. This may be used to determine whether to perform a first random access operation or a second random access operation, which will be described later.

The Make-Before-Break HO refers to a technique for performing a handover operation immediately after receiving a handover command, but continuously transmitting and receiving data with a source cell. In addition, the UE-based HO does not immediately perform a handover operation even after receiving a handover command, and a predetermined handover condition (eg, a value set by the signal strength of the target base station) included in the handover command message. above) is satisfied, the UE determines the handover time. The RACH-less HO indicates that the target base station does not perform random access. For example, when the size of the target cell is small or the cell size of the source cell is similar, a method of omitting uplink synchronization may be used.

If the above Make-Before-Break HO (MBB; 1st HO) and/or UE-based HO (or conditional HO, 2nd HO) is indicated, the UE meets the handover ready condition The source base station maintains data transmission/reception until it becomes available (3f-07). The handover preparation condition means a point in time when the first uplink transmission is possible in the destination base station if the Make-Before-Break HO is set, and if the UE-based HO is set, it is indicated in the handover command It means a case in which a predetermined handover condition is satisfied. In addition, when the Make-Before-Break HO and the UE-based HO are configured at the same time, a time when the first uplink transmission is possible in the target base station may be used as in the case where the Make-Before-Break HO is configured. (That is, even when a predetermined handover condition indicated in the handover command is met, the target base station can continue to communicate with the source base station until the first uplink transmission becomes possible).

Upon receiving the Make-Before-Break HO, the terminal receiving the handover command immediately receives the UE-based HO command, and when a predetermined condition included in the handover command is satisfied, the target (target) base station A synchronization process with the corresponding target base station is performed through reception of a reference signal or synchronization signal transmitted from (3f-09). In addition, the second layer (eg, MAC layer) of the terminal is initialized (3f-11), and the configuration information related to the first layer (eg, physical layer) received from the handover command is applied (3f-13) ). Meanwhile, an encryption key to be used in the target base station is generated, and additionally generated keys from the generated key are applied to future communication (3f-15). Accordingly, a response message to the handover command message is generated, and an encryption and integrity check code is added to the additionally generated additional keys, and then transmitted to a lower layer (ie, MAC and physical layer) (3f-17).

If RACH-less HO is not indicated in the handover command message (3f-19), the UE initiates random access to the target base station (3f-21). In this case, if the target base station is a cell configured with one beam, a first random access procedure is performed, and if the target base station is a cell configured with a plurality of beams, a second random access procedure is performed. Currently, low-frequency cells are mostly composed of a single beam, but the NR system can operate at high frequencies (eg, several tens of GHz). and a cell composed of a plurality of beams used can be used.

In the first random access procedure, the UE transmits a preamble, receives a response message (RAR) from the base station, transmits message 3 (eg, HO complete message), and receives the identifier (C-RNTI) of the UE in the PDCCH. made by the procedure. In the RAR message, transmission resource information for transmission of the message 3 is accommodated, and when the message 3 is transmitted, the terminal transmits the beam without applying beamforming, and the terminal identifier (C) of the terminal to be used in the target base station, which is received in the handover command. -RNTI) contains all or part of the C-RNTI MAC CE and RRC connection reconfiguration complete message including information.

In the second random access procedure, the UE transmits a preamble, receives a response message (RAR) from the base station, transmits message 3 (eg, HO complete message), and receives the identifier (C-RNTI) of the UE in the PDCCH. is made of In this case, when transmitting the preamble, it is assumed that the UE transmits a plurality of the same preamble to the base station using beams in different directions, and accordingly, the RAR message includes transmission resource information for message 3 transmission and the preamble Accommodates beam identifier information of one terminal, and when transmitting message 3, the terminal transmits message 3 using the corresponding beam according to the received RAR information (that is, by applying beamforming), and the message 3 is the hand The C-RNTI MAC CE including the terminal identifier (C-RNTI) information to be used by the target base station received in the over command and the best downlink transmission beam information among multiple beams of the base station (for example, the identifier or beam of the synchronization reference signal) index information) and all or part of the RRC connection reconfiguration complete message.

According to the above procedure (that is, the first random access procedure or the second random access procedure), the MAC layer of the terminal performs the random access to the target base station to receive uplink synchronization and uplink resource allocation, When the generated handover completion message is transmitted in message 3 and the PDCCH addressed to the C-RNTI is received from the target cell (that is, when the random access is successfully completed), it is determined that the handover has been successfully performed. (3f-23).

On the other hand, if RACH-less HO is indicated in the handover command message, if the UE receives the PDCCH addressed to the C-RNTI in the target cell without transmitting the preamble, it is determined that the handover has been successfully performed ( 3f-23).

When it is determined that the handover has been successfully performed as described above, the terminal transmits a channel quality report through a predetermined channel (eg, PUCCH) according to the physical layer setting in the target base station included in the handover command. (3f-25), and can receive an unobtained System Information Block (SIB) (3f-27), after which the terminal becomes the serving base station and transmits and receives data with the corresponding base station. can be done

3G shows a block configuration of a terminal according to an embodiment of the present invention.

Referring to FIG. 3G, the terminal includes a radio frequency (RF) processing unit (3g-10), a baseband processing unit (3g-20), a storage unit (3g-30), and a control unit (3g-40). do.

The RF processing unit 3g-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processor 3g-10 up-converts the baseband signal provided from the baseband processor 3g-20 into an RF band signal, transmits it through an antenna, and receives the RF band signal through the antenna. downconverted to a baseband signal. For example, the RF processing unit 3g-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), and the like. can Although only one antenna is shown in FIG. 3G, the terminal may include a plurality of antennas. Also, the RF processing unit 3g-10 may include a plurality of RF chains. Furthermore, the RF processing unit 3g-10 may perform beamforming. For the beamforming, the RF processing unit 3g-10 may adjust the phase and magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements.

The baseband processing unit 3g-20 performs a function of converting between a baseband signal and a bit stream according to a physical layer standard of the system. For example, when transmitting data, the baseband processing unit 3g-20 generates complex symbols by encoding and modulating a transmitted bit stream. Also, when receiving data, the baseband processing unit 3g-20 restores the received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 3g-10. For example, in the case of orthogonal frequency division multiplexing (OFDM), when transmitting data, the baseband processing unit 3g-20 encodes and modulates a transmission bit stream to generate complex symbols, and convert the complex symbols to subcarriers. After mapping to , OFDM symbols are constructed through inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit 3g-20 divides the baseband signal provided from the RF processing unit 3g-10 into OFDM symbol units, and performs a fast Fourier transform (FFT) operation on the subcarriers. After reconstructing the mapped signals, the received bit stream is reconstructed through demodulation and decoding.

The baseband processing unit 3g-20 and the RF processing unit 3g-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 3g-20 and the RF processing unit 3g-10 may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. In addition, at least one of the baseband processing unit 3g-20 and the RF processing unit 3g-10 may include different communication modules to process signals of different frequency bands. The different frequency bands may include a super high frequency (SHF) (eg, 2.5 GHz, 5 GHz) band and a millimeter wave (eg, 60 GHz) band.

The storage unit 3g-30 stores data such as a basic program, an application program, and setting information for the operation of the terminal.

The controller 3g-40 controls overall operations of the terminal. For example, the control unit 3g-40 transmits and receives signals through the baseband processing unit 3g-20 and the RF processing unit 3g-10. In addition, the control unit 3g-40 writes and reads data in the storage unit 3g-40. To this end, the controller 3g-40 may include at least one processor. For example, the controller 3g-40 may include a communication processor (CP) that controls for communication and an application processor (AP) that controls an upper layer such as an application program. According to an embodiment of the present invention, the control unit 3g-40 includes a multi-connection processing unit 3g-42 that performs processing for operating in the multi-connection mode. For example, the controller 3g-40 may control the terminal to perform the procedure shown in the operation of the terminal shown in FIG. 3g.

According to an embodiment of the present invention, the terminal receives a message instructing measurement from the base station. Upon receiving this, the control unit performs handover using the handover method 1 (FIGS. 3C and 3D) or method 2 (FIGS. 3E and 3F), which is performed according to the types of the source and target base stations.

<Fourth embodiment>

4A is a diagram illustrating the structure of an LTE system to which the present invention can be applied.

Referring to FIG. 4A, as shown, the radio access network of the LTE system is a next-generation base station (Evolved Node B, hereinafter ENB, Node B or base station) (4a-05, 4a-10, 4a-15, 4a-20) and It consists of MME (4a-25, Mobility Management Entity) and S-GW (4a-30, Serving-Gateway). User equipment (hereinafter referred to as UE or terminal) 4a-35 accesses an external network through ENBs 4a-05 to 4a-20 and S-GW 4a-30.

In FIG. 4A , ENBs 4a-05 to 4a-20 correspond to the existing Node Bs of the UMTS system. ENB is connected to the UE (4a-35) through a radio channel and performs a more complex role than the existing Node B. In the LTE system, all user traffic, including real-time services such as VoIP (Voice over IP) through the Internet protocol, are serviced through a shared channel, so status information such as buffer status, available transmission power status, and channel status of UEs A device for scheduling is required, and the ENB (4a-05 ~ 4a-20) is responsible for this. One ENB typically controls multiple cells. For example, in order to implement a transmission rate of 100 Mbps, the LTE system uses, for example, Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a radio access technology in a 20 MHz bandwidth. In addition, an Adaptive Modulation & Coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel state of the terminal is applied. The S-GW (4a-30) is a device that provides a data bearer, and creates or removes a data bearer under the control of the MME (4a-25). The MME is a device responsible for various control functions as well as the mobility management function for the UE, and is connected to a number of base stations.

4B is a diagram illustrating a radio protocol structure in an LTE system to which the present invention can be applied.

Referring to FIG. 4b, the radio protocols of the LTE system are PDCP (Packet Data Convergence Protocol 4b-05, 4b-40), RLC (Radio Link Control 4b-10, 4b-35), MAC (Medium Access) in the UE and ENB, respectively. Control 4b-15, 4b-30). The Packet Data Convergence Protocol (PDCP) (4b-05, 4b-40) is in charge of IP header compression/restore operations. The main functions of PDCP are summarized below.

- Header compression and decompression (ROHC only)

- Transfer of user data

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

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

- Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM)

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

- Encryption and decryption function (Ciphering and deciphering)

- Timer-based SDU discard in uplink.

The radio link control (Radio Link Control, hereinafter referred to as RLC) 4b-10, 4b-35 reconfigures a PDCP packet data unit (PDU) to an appropriate size and performs an ARQ operation and the like. The main functions of RLC are summarized below.

- Data transfer function (Transfer of upper layer PDUs)

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

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

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

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

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

- Protocol error detection (only for AM data transfer)

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

- RLC re-establishment function (RLC re-establishment)

The MACs 4b-15 and 4b-30 are connected to several RLC layer devices configured in one terminal, and perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized below.

- Mapping function (Mapping between logical channels and transport channels)

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

- Scheduling information reporting function (Scheduling information reporting)

- HARQ function (Error correction through HARQ)

- Priority handling between logical channels of one UE

- Priority handling between UEs by means of dynamic scheduling

- MBMS service identification

- Transport format selection

- Padding function

The physical layer (4b-20, 4b-25) channel-codes and modulates upper layer data, converts it into an OFDM symbol and transmits it over a radio channel, or demodulates and channel-decodes an OFDM symbol received through the radio channel and transmits it to an upper layer do the action

4C is a diagram illustrating the structure of a next-generation mobile communication system to which the present invention can be applied.

4c, as shown, the radio access network of the next-generation mobile communication system (hereinafter NR or 5G) includes a next-generation base station (New Radio Node B, hereinafter, NR gNB or NR base station) 4c-10 and NR CN 4c -05, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter NR UE or terminal) 4c-15 accesses an external network through NR gNB 4c-10 and NR CN 4c-05.

In FIG. 4C , the NR gNBs 4c-10 correspond to an Evolved Node B (eNB) of the existing LTE system. The NR gNB is connected to the NR UE 4c-15 through a radio channel and can provide a superior service than the existing Node B. In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device for scheduling by collecting status information such as buffer status, available transmission power status, and channel status of UEs is required. (4c-10) is in charge. One NR gNB typically controls multiple cells. In order to implement ultra-high-speed data transmission compared to current LTE, it can have more than the existing maximum bandwidth, and additionally beamforming technology can be grafted by using Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a radio access technology. . In addition, an Adaptive Modulation & Coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel state of the terminal is applied. The NR CN (4c-05) performs functions such as mobility support, bearer setup, QoS setup, and the like. NR CN is a device in charge of various control functions as well as mobility management functions for the terminal and is connected to a number of base stations. In addition, the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN is connected to the MME (4c-25) through a network interface. The MME is connected to the existing base station eNB (4c-30).

4D is a diagram illustrating a radio protocol structure of a next-generation mobile communication system to which the present invention can be applied. .

Referring to FIG. 4d, the radio protocols of the next-generation mobile communication system are NR PDCP (4d-05, 4d-40), NR RLC (4d-10, 4d-35), and NR MAC (4d-15) in the terminal and the NR base station, respectively. , 4d-30). The main function of NR PDCP (4d-05, 4d-40) may include some of the following functions.

Header compression and decompression (ROHC only)

- Transfer of user data

- In-sequence delivery of upper layer PDUs

- Order reordering function (PDCP PDU reordering for reception)

- Duplicate detection of lower layer SDUs

- Retransmission of PDCP SDUs

- Encryption and decryption function (Ciphering and deciphering)

- Timer-based SDU discard in uplink.

In the above, the reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN), and a function of delivering data to a higher layer in the reordered order may include a function of reordering the order to record the lost PDCP PDUs, and may include a function of reporting a status on the lost PDCP PDUs to the transmitting side, and the lost PDCP PDUs It may include a function to request retransmission for .

The main function of the NR RLC (4d-10, 4d-35) may include some of the following functions.

- Data transfer function (Transfer of upper layer PDUs)

- In-sequence delivery of upper layer PDUs

- Out-of-sequence delivery of upper layer PDUs

- ARQ function (Error Correction through ARQ)

- Concatenation, segmentation and reassembly of RLC SDUs

- Re-segmentation of RLC data PDUs

- Reordering of RLC data PDUs

- Duplicate detection

- Protocol error detection

- RLC SDU discard function (RLC SDU discard)

- RLC re-establishment function (RLC re-establishment)

In the above, the in-sequence delivery function of the NR RLC device refers to a function of sequentially delivering RLC SDUs received from a lower layer to an upper layer, and one RLC SDU is originally divided into several RLC SDUs and received If it is, it may include a function of reassembling it and delivering it, and may include a function of rearranging the received RLC PDUs based on an RLC sequence number (SN) or PDCP SN (sequence number), and rearranging the order May include a function of recording the lost RLC PDUs, may include a function of reporting a status on the lost RLC PDUs to the transmitting side, and may include a function of requesting retransmission for the lost RLC PDUs. and, when there is a lost RLC SDU, it may include a function of sequentially delivering only RLC SDUs before the lost RLC SDU to the upper layer, or even if there is a lost RLC SDU, if a predetermined timer has expired It may include a function of sequentially delivering all RLC SDUs received before the start of RLC to the upper layer, or if a predetermined timer expires even if there are lost RLC SDUs, all RLC SDUs received so far are sequentially transferred to the upper layer. It may include a function to transmit. In addition, the RLC PDUs may be processed in the order in which they are received (in the order of arrival, regardless of the sequence number and sequence number) and delivered to the PDCP device out of sequence (out-of sequence delivery). Segments stored in the buffer or to be received later are received, reconstructed into one complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and the function may be performed by the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.

In the above, the out-of-sequence delivery function of the NR RLC device refers to a function of directly delivering RLC SDUs received from a lower layer to a higher layer regardless of order, and one RLC SDU originally has several RLCs. When received after being divided into SDUs, it may include a function of reassembling and delivering it, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs, arranging the order, and recording the lost RLC PDUs. can

The NR MACs 4d-15 and 4d-30 may be connected to several NR RLC layer devices configured in one terminal, and the main function of the NR MAC may include some of the following functions.

- Mapping function (Mapping between logical channels and transport channels)

- Multiplexing/demultiplexing of MAC SDUs

- Scheduling information reporting function (Scheduling information reporting)

- HARQ function (Error correction through HARQ)

- Priority handling between logical channels of one UE

- Priority handling between UEs by means of dynamic scheduling

- MBMS service identification

- Transport format selection

- Padding function

The NR PHY layer (4d-20, 4d-25) channel-codes and modulates upper layer data, makes an OFDM symbol and transmits it to a radio channel, or demodulates and channel-decodes an OFDM symbol received through a radio channel to a higher layer. You can perform a forwarding action.

4E is a diagram illustrating modes in which a terminal can stay in the next-generation mobile communication system of the present invention.

In Figure 4e, the UE is in RRC connected mode (RRC connected mode, 4e-03), RRC inactive mode (RRC inactive mode, 4e-02) or lightly-connected mode (4e-02), RRC idle mode (RRC idle mode, 4e) -01), and can go through the processes (4e-05, 4e-10, 4e-15, 4e-20, 4e-25) of switching to different modes. That is, when the terminal in the RRC idle mode (4e-01) has data to transmit in uplink or when downlink data arrives and receives a paging message, or to update the tracking area (periodically or out of the tracking area) case) may be switched to the RRC connection mode (4e-03) to transmit and receive data by establishing a connection with the network (4e-05). If data does not occur for a certain period of time after data transmission and reception, the UE in the RRC connected mode may be switched to the RRC idle mode by the network (4e-15). In addition, if data does not occur for a certain period of time, the terminal in the RRC connected mode (4e-03) switches to the RRC deactivation mode (4e-02) by the network or by itself switching the mode for the purpose of saving battery and supporting fast connection Can (4e-20). The UE in the RRC deactivation mode (4e-03) has data to transmit on the uplink or when downlink data arrives and receives a paging message, or to update a tracking area (or RAN Notification area) ( Periodically or when out of the tracking area (or LAN indication area)), the RRC connection mode (4e-03) can be switched to the RRC connection mode (4e-03) to establish a connection with the network (4e-10) RRC deactivation mode (4e) -03), the terminal in the RRC idle mode (4e-01) may transition to the RRC idle mode (4e-01) by itself according to the instruction of the network or by a preset configuration (4e-25). If there are many in the network, this is an operation that should be supported because the signaling overhead of the network may increase due to the frequent LAN indication area update procedure In the case of a terminal having a predetermined purpose, the RRC deactivation mode (4e-) without transitioning to the RRC connected mode 03) can also transmit data, and the transition is repeated according to the instruction of the network between the RRC deactivation mode and the RRC idle mode, and the transition to the RRC connected mode can be performed only when necessary. By transmitting data in the RRC deactivation mode, it has the advantage that it can have a very short transmission delay and a very small signaling overhead. In addition, the UE in the RRC idle mode (4e-01) may immediately transition to the RRC deactivation mode (4e-03) by the network. Also, it may transition to the RRC connected mode and then to the RRC deactivation mode (4e-03, 4e-20).

In the above, when the terminal performs transition between modes, an additional timer (inactive timer) is set in the terminal to solve the problem of state mismatch between the mode of the terminal and the mode of the terminal recognized by the network. can In addition, an additional timer may be driven in the base station.

In the present invention, it can be interpreted as a mode in the same state as the RRC inactive mode and the lightly-connected mode, and it can be assumed that the terminal performs the same operation. Also, although the RRC inactive mode and the lightly-connected mode may be interpreted as modes in the same state, it may be assumed that the terminal performs different operations in each mode. In addition, the RRC inactive mode and the lightly-connected mode may be interpreted as modes in different states, and it may be assumed that the terminal performs different operations in each mode. As described above, the RRC inactive mode and the lightly-connected mode have the same purpose in that they are modes that can save battery while enabling fast reconnection with little signaling, but are the same mode according to the implementation and definition of the terminal and the network. may be or may be other modes. In addition, in the above, the terminal operation in the RRC inactive mode and the lightly-connected mode has the same or additional functions as the operation in the RRC idle mode, or has only some functions during the operation in the RRC idle mode. can As described above, in the RRC deactivation mode, the battery of the terminal is saved, and when the terminal connects to the network, there is an advantage that a fast connection can be established with a small signaling overhead. However, the UE in the RRC deactivation mode should perform a procedure of updating the RAN Notification area more frequently than the procedure of periodically updating the tracking area of the UE in the RRC idle mode. Therefore, if there are too many RRC deactivation mode terminals in the network, signaling overhead due to the periodic LAN indication area update procedure may be caused. Therefore, the network should be able to manage the RRC deactivation mode terminals and switch to the RRC idle mode if necessary.

4f shows a procedure for a terminal to switch from an RRC connected mode to an RRC idle mode and a procedure for switching from an RRC idle mode to an RRC connected mode in the present invention. It is a drawing explaining the procedure.

In FIG. 4f, the base station transmits an RRCConnectionRelease message to the terminal when the terminal that transmits and receives data in the RRC connected mode does not transmit or receive data for a predetermined reason or for a predetermined time to switch the terminal to the RRC idle mode (4f-01). Later, when data to be transmitted is generated, a terminal currently not currently established (hereinafter, idle mode UE) performs an RRC connection establishment process with the base station. The terminal establishes reverse transmission synchronization with the base station through a random access process and transmits an RRCConnectionRequest message to the base station (4f-05). The message contains an identifier of the terminal and a reason for establishing a connection (establishmentCause). The base station transmits an RRCConnectionSetup message so that the terminal establishes an RRC connection (4f-10). The message includes RRC connection configuration information and the like. The RRC connection is also called a Signaling Radio Bearer (SRB), and is used for transmitting and receiving RRC messages, which are control messages between the UE and the base station. The terminal that has established the RRC connection transmits an RRCConnetionSetupComplete message to the base station (4f-15). The message includes a control message called SERVICE REQUEST in which the UE requests the MME to establish a bearer for a predetermined service. The base station transmits the SERVICE REQUEST message contained in the RRCConnetionSetupComplete message to the MME (4f-20), and the MME determines whether to provide the service requested by the terminal. As a result of the determination, if it is determined that the terminal provides the requested service, the MME transmits an INITIAL CONTEXT SETUP REQUEST message to the base station (4f-25). The message includes information such as Quality of Service (QoS) information to be applied when configuring a Data Radio Bearer (DRB), and security-related information (eg, Security Key, Security Algorithm) to be applied to the DRB. The base station exchanges a SecurityModeCommand message (4f-30) and a SecurityModeComplete message (4f-35) to establish security with the terminal. When the security setting is completed, the base station transmits an RRCConnectionReconfiguration message to the terminal (4f-40). The message includes the configuration information of the DRB to be processed by the user data, and the terminal applies the information to configure the DRB and transmits an RRCConnectionReconfigurationComplete message to the base station (4f-45). The base station, which has completed DRB setup with the UE, transmits an INITIAL CONTEXT SETUP COMPLETE message to the MME (4f-50), and the MME that receives it sends an S1 BEARER SETUP message and an S1 BEARER SETUP RESPONSE message to establish an S1 bearer with the S-GW. exchange (4f-055, 4f-60). The S1 bearer is a data transmission connection established between the S-GW and the base station, and corresponds to the DRB in a one-to-one manner. When all of the above processes are completed, the terminal transmits and receives data through the base station and the S-GW (4f-65, 4f-70). As such, the general data transmission process consists of three steps: RRC connection setup, security setup, and DRB setup. In addition, the base station may transmit an RRCConnectionReconfiguration message to refresh, add, or change a configuration to the terminal for a predetermined reason (4f-75).

As described above, many signaling procedures are required to switch from the RRC idle mode to the RRC connected mode. Therefore, in the next-generation mobile communication system, the RRC inactive mode or lightly-connected mode can be newly defined, and in the new mode as described above, the terminal and the base station store the context of the terminal and, if necessary, maintain the S1 bearer. Faster access with fewer signaling procedures.

4G is a diagram illustrating a procedure for a terminal to switch from an RRC connected mode to an RRC inactive mode (or lightly-connected mode) and a procedure for switching from an RRC inactive mode (or lightly-connected mode) to an RRC connected mode in the present invention.

In Figure 4g, the terminal and the base station are a terminal (4g-01), a fixed base station (anchor gNB, 4g-02), and a new base station (New gNB, 4g-) for performing a procedure for reusing a UE context and an S1 bearer. 03), shows the overall flow of MME (4g-04). The terminal 4g-01 in the RRC connection state performs data transmission/reception with the base station. When data transmission/reception is stopped, the base station drives a predetermined timer, and if data transmission/reception is not resumed until the timer expires (4g-05), the base station may consider releasing the RRC connection of the terminal, and the base station may It can be determined whether to send the UE to the RRC idle mode or the RRC deactivated mode according to the The predetermined condition may consider the degree of network traffic, the amount of terminal contexts that the network can maintain, the number of terminals that the network can support, and the like. In order to send the UE to the RRC deactivation mode or light connected mode in step 4g-10, an RRCConnectionRelease or RRCConnectionSuspend message, a newly defined RRC message, or another existing RRC message may be reused and transmitted. In 4g-10, the base station releases the RRC connection of the terminal according to a predetermined rule, stores the UE context, and assigns a Resume ID while transmitting a control message instructing the terminal to release the RRC connection, and the terminal is in light connected mode It is possible to set a paging area (PA) in which mobility is to be reported during the operation. At this time, the UE can know that the UE needs to store the UE context by assigning the Resume ID, or in the message, the eNB indicates that the UE operates in the RRC deactivation mode/light connected mode and stores the UE context. It is also possible to send a separate context maintenance indicator for (4g-10). In addition, the message may include security information for updating security settings required when the terminal performs an RRC connection resumption procedure later. For example, NCC (NextHopChainingCount) is pre-allocated, and a new security key (KeNB* or KgNB*) can be calculated and set using this. In addition, the control message may include a list of cells to which a procedure using a stored context can be applied when the base station maintains the context or the terminal intends to re-establish the RRC connection within the validity period. After the base station releases the RRC connection of the terminal, the UE context and the S1 bearer of the terminal are maintained as they are (4g-15). The S1 bearer refers to the S1-control bearer used for exchanging control messages between the base station and the MME and the S1-user plane bearer used for exchanging user data between the base station and the S-GW. By maintaining the S1 bearer, the procedure for establishing the S1 bearer can be omitted when the UE attempts to establish an RRC connection in the same cell or in the same base station. The base station may delete the UE context and release the S1 bearer when the validity period expires. Upon receiving the RRC connection release message in step 4g-10, the UE switches to the RRC deactivation mode/light connected mode.

In the above, the fixed base station refers to a base station that maintains and manages the terminal context (resume ID) of the RRC deactivation mode terminal and manages the RAN paging area or RAN Notification area in order to manage the mobility of the RRC deactivation mode terminal. . The role of the fixed base station described above may be performed by an Access and Mobility Management Function (AMF) device instead.

The base station transmits a control message requesting a connection temporary stop to the MME (4g-20). Upon receiving the control message, the MME may directly transmit the downlink data to the fixed base station when downlink data for the terminal is generated to the S-GW, and the fixed base station may generate a paging message and transmit it to the neighboring base station ( 4g-35). That is, the fixed base station that has received the downlink data stores the data in a buffer and performs a paging procedure. The fixed base station refers to a base station that maintains a terminal context of the terminal and an S1-U bearer. Alternatively, when the fixed base station sends a paging message and there is no response from the terminal, that is, when paging fails, the fixed base station may request a paging procedure from the MME, and the MME generates downlink data for the terminal from the S-GW. Instructs the MME to initiate a paging procedure without forwarding the downlink data to the base station, and the S-GW may operate accordingly (4g-35).

Upon receiving the RRC connection release message (4g-10) including the context maintenance information and the Resume ID, the UE releases the RRC connection, but drives a timer corresponding to the valid period and writes the valid cell list to the memory. It does not delete the current terminal context, but keeps it in memory (4g-25) and transitions to the light connected mode. In the above, the UE context refers to various pieces of information related to the RRC configuration of the UE, and includes SRB configuration information, DRB configuration information, security key information, and the like. After this, there arises a need to establish an RRC connection for some reason (4g-30). A UE that has not been assigned a Resume ID in the previous RRC connection release process or that the context is not maintained starts the general RRC connection establishment process (FIG. 4f) described in FIG. 4f, but allocates a Resume ID in the previous RRC connection release process The received RRC deactivation mode/light connected mode terminal may attempt an RRC connection resumption process using the stored terminal context. In the above, the RRC deactivation mode/light connected mode terminal may perform a general RRC connection establishment process (FIG. 4f) depending on whether the network supports RRC deactivation mode/light connection, or may perform an RRC connection resumption process using the stored terminal context. may be That is, if the RRC deactivation mode/light connection mode is not supported, a general RRC connection establishment process ( FIG. 4f ) may be performed, and if supported, the RRC connection resumption procedure may be performed as follows. In the above, the RRC deactivation mode may always be supported in the network (therefore, system information may not separately inform whether it is supported). In the present invention, each base station or cell may transmit system information including an indicator indicating whether each base station or cell supports light connection or not. The indicator may be included in the second block of system information (Systeminformation2), or may be included in blocks of other system information (Systeminformation1-19). In the above, supporting light connection corresponds to the following procedures (4g-50, 4g-55, 4g-60, 4g-65, 4g-70, 4g-75, 4g-80, 4g-85, 4g-90). It can be said that the base station or the corresponding cell can configure and support it. When the light connected mode UE needs to establish an RRC connection, it reads the system information of the cell currently camped on. If the system information does not include an indicator indicating that the base station or cell supports light connection (or RRC deactivation mode), the UE may perform the general RRC connection establishment process (FIG. 4f) described with reference to FIG. 4f (4g). -45). However, if the system information includes an indicator indicating that the base station or cell supports light connection (or RRC deactivation mode), the terminal may perform the RRC connection resumption process using the stored terminal context (4g-45). The RRC connection resumption process using the stored terminal context is as follows.

First, the UE transmits a preamble in message 1 to perform a random access procedure. If resource allocation is possible according to the preamble received in message 1, the base station allocates a corresponding uplink resource to the terminal in message 2; The UE transmits a resume request message including the Resume ID received in step 4g-10 based on the received uplink resource information (4g-50). The message may be a modified message of the RRCConnectionRequest message or a newly defined message (eg, RRCConnectionResumeRequest). If the terminal in the light connected mode after disconnecting from the existing fixed base station 4g-02 moves and camps on the cell of another base station, the new base station 4g-03 receives and confirms the Resume ID of the terminal It can be known from which base station the terminal has previously received the service. If the new base station 4g-03 has successfully received and confirmed the Resume ID, a procedure for retrieving the UE context from the existing base station 4g-02 is performed (Context Retrieve Procedure. 4g-55, 4g-60). If the procedure for recovering the terminal context fails, for example, if the fixed/source base station cannot be found or the terminal context does not exist for a predetermined reason, the base station sends an RRCConnectionSetup message instead of the RRCConnectionResume message as shown in FIG. 4f. and the subsequent bearer establishment procedure/security establishment procedure may fall back to the RRC connection establishment procedure described in FIG. 4f, complete security establishment, and send the terminal to the RRC connected mode, or a new terminal identifier ( resume ID) and the LAN paging area, while sending the RRCConnectionSuspend message, the UE may return to the RRC deactivation mode again. The terminal context may be obtained from the existing base station 4g-02 by the new base station 4g-03 through the S1 or X2 interface. (If the new base station receives the Resume ID, but does not successfully identify the terminal for a certain reason, it may send an RRCConnectionSetup message to the terminal and return to the general RRC connection setup procedure described in FIG. 4f. That is, the RRCConnectionSetup message is transmitted to the terminal When the terminal receives the message, it can establish a connection by sending an RRCConnectionSetupComplete message to the base station, or if a new base station receives the Resume ID but does not successfully identify the terminal (e.g., retrieves the terminal context from the existing fixed base station) fails) by sending an RRCConnectionRelease message or RRCConnectionReject message to the terminal to reject the terminal's connection and try again the general RRC connection establishment procedure described in FIG. 4f from the beginning.) Check MAC-I based on (4g-65). The MAC-I is a message authentication code calculated by the terminal for a control message by applying the security information of the restored terminal context, that is, by applying a security key and a security counter. The base station checks the integrity of the message by using the MAC-I of the message, the security key and security counter stored in the context of the terminal. Then, the new base station 4g-03 determines a configuration to be applied to the RRC connection of the terminal, and transmits an RRC connection resume message (RRCConnectionResume) containing the configuration information to the terminal (4g-70). The RRC connection resume message may be transmitted by the base station confirming the terminal identifier (Resume ID) of the terminal and encrypting it using a new security key (KeNB* or KgNB*), and the terminal receives the NCC pre-allocated in the 4g-10 The RRC connection resume message can be normally received by decrypting it using a new security key (KeNB* or KgNB*) calculated using . After the procedure of sending the RRC connection resume message, the RRC message and data can be encrypted with a new security key so that the terminal and the base station can transmit and receive. The RRC connection resumption message may be a control message including information indicating 'RRC context reuse' (REUSE INDICATOR) in a general RRC connection request message. Like the RRC connection establishment message, the RRC connection resume message contains various pieces of information related to the RRC connection establishment of the UE. When the terminal receives a general RRC connection setup message (RRCConnectionSetup), it establishes an RRC connection based on the setup information indicated in the RRC connection setup message, but when receiving the RRC connection resume message, the stored setup information and the control The RRC connection is established in consideration of all the configuration information indicated in the message (Delta configuration). In other words, it is possible to determine the configuration information to be applied by determining the indicated configuration information as delta information for the configuration information storing the configuration information, and to update the configuration information or the UE context. For example, if the RRC connection resume message includes SRB configuration information, the SRB is configured by applying the indicated SRB configuration information. If the RRC connection resume message does not include SRB configuration information, the SRB stored in the UE context. Configure the SRB by applying the setting information.

The UE configures an RRC connection by applying the updated UE context and configuration information, and transmits an RRC connection resumption completion message to the eNB (4g-75). Then, it transmits a control message requesting release of the connection temporary stop to the MME and requests to reconfigure the S1 bearer to a new base station (4g-80, 4g-85). Upon receiving the message, the MME instructs the S-GW to reset the S1 bearer to a new base station and to process data for the terminal normally. When the above process is completed, the terminal resumes data transmission and reception in the cell (4g-90).

In the above procedure, if the terminal in the light connected mode after disconnecting from the existing fixed base station 4g-02 camps on the cell 4g-02 of the existing fixed base station again because the terminal does not move significantly, the existing fixed base station 4g -03) does not perform the procedures of 4g-55 and 4g-60, but only releases the connection temporary stop of the S1 bearer instead of the procedures of 4g-80 and 4g-85, and refers to the Resume ID indicated in message 3 of the terminal It is possible to search the terminal context of , and reconfigure the connection based on this in a method similar to the above procedures.

If data transmission/reception is stopped, the base station drives a predetermined timer, and if data transmission/reception is not resumed until the timer expires (4g-95), the base station considers releasing the RRC connection of the terminal. In order to send the UE to the RRC deactivated state or light connected state in step 4g-100, an RRCConnectionRelease or RRCConnectionSuspend message, a newly defined RRC message, or another existing RRC message may be reused and transmitted. In the process 4g-100, the base station releases the RRC connection of the terminal according to a predetermined rule, stores the UE context, and allocates a new terminal identifier (Resume ID) while transmitting a control message instructing the terminal to release the RRC connection and sets a RAN paging area (RAN Paging area or RAN Notification area) in which the UE reports mobility during RRC deactivation mode (or light connected mode) (4g-100). When the terminal 4g-105 in the RRC deactivation mode (light connected mode) leaves the set LAN paging area, it performs a procedure of updating the LAN paging area.

In the next-generation mobile communication system, the base station sets the terminal to the RRC deactivation mode while setting the terminal to a terminal identifier (resume ID) that can be used when an RRC connection is attempted later and a RAN paging area (RAN paging area or RAN) so that the terminal reports mobility. Notification area) can be set. In addition, a NCC (NexthopChainingCount) value may be set for security setting to be used in the subsequent connection setting process.

In the next-generation mobile communication system, the RRC-deactivated terminal performs a tracking area update procedure (Tracking Area Update, TAU) when it leaves the tracking area (TA) or TA list set in the network/MME/CN (Core Network), and , when the Access and Mobility Management Function (AMF) or fixed base station leaves the configured RAN paging area (RAN paging area or RAN Notification area), the RAN paging area update procedure is performed. In the network, when the UE in the RRC deactivation mode performs the LAN paging area update procedure, it may respond with various messages depending on the network conditions, and the present invention proposes a message transmission/reception procedure in consideration of various cases.

4H is a diagram illustrating a response of a base station to performing a LAN paging area update procedure when a terminal leaves a currently set LAN paging area while moving in an RRC inactive mode (or lightly-connected mode) in the present invention.

In FIG. 4H , the terminal 4h-05 in the RRC deactivation mode attempts to access the network in order to perform a LAN paging area update procedure when it leaves the currently set LAN paging area while moving. In the above, the UE first performs a random access procedure, first transmits a random access preamble (4h-15), and in response to this, receives an RAR at 4h-20. In the above, the random access procedure is performed and the terminal can be used by defining a terminal identifier (Resume ID), a connection cause indicator (causeValue, for example, a new causeValue, for example, a new causeValue) in the RRCConnectionResumeRequest message as message 3, ranNotificationAreaUpdateRequest), shortMAC-I (of the message indicator for integrity verification), and the like. The reason for sending the RRCConnectionResumeRequest message in the above is when downlink data from the base station to the terminal occurs when the terminal attempts to access to update the LAN paging area, or it is necessary to switch the terminal to the RRC connection mode for some reason. This is so that the base station can switch the mode of the terminal when there is. The base station receiving the message from the terminal in 4h-25 checks the terminal identifier (resume ID), identifies the existing fixed base station having the identifier of the terminal, and sends the terminal identifier to the existing base station to recover the terminal context for the terminal Carry out the procedure (4h-30, 4h-35). In addition, a bearer path modification procedure may be performed to modify a bearer path to a new base station to which the UE is connected (4h-40, 4h-45, 4h-50, 4h-55). In the above, the base station may omit the bearer path modification procedure (4h-40, 4h-45, 4h-50, 4h-55) in order to quickly update only the LAN paging area of the terminal.

The base station determines to maintain the terminal in RRC deactivation mode in step 4h-60, or when there is no downlink data to the terminal, a new terminal identifier (resume ID) and a new LAN to update the LAN paging area of the terminal By sending an RRCConnectionSuspend message to the terminal, including paging area setting information (RAN Paging Area information, RPA info.), security setting information (NCC, NexthopChainingCounter), etc., the terminal can continue to be in RRC deactivation mode (4h-65) . In the above, the RAN paging area configuration information may include a list of cell identifiers or a RAN paging area ID or information indicating a tracking area. Also, the LAN paging area information may be delta signaling. That is, information for instructing to reuse the previously used LAN paging area information or adding or deleting some area/cell identifiers in the existing LAN paging area may be added. In the above, the security configuration information may be applied to generate a new security key, and may be used to decrypt the RRC message from the base station and verify the integrity in the subsequent RRC connection establishment process.

In step 4h-60, the base station checks whether downlink data to the terminal exists, and when there is downlink data, or when it is necessary to switch the terminal to the RRC connected mode for a predetermined reason (eg, network If the resource of the RRC connection mode is sufficient to manage the UE in the RRC connected mode), an attempt may be made to switch the UE to the RRC connected mode by sending an RRCConnectionResume message to the UE. In the above, the RRCConnectionResume message can be transmitted by encrypting it with a new security key and performing integrity verification, and the terminal uses the RRCConnectionSuspend message to convert the terminal to the RRC deactivation mode. The RRCConnectionResume message can be decrypted by calculating a new security key by using it, and integrity verification can be performed and received. Upon receiving the RRCConnectionResume message, the terminal may send an RRCConnectionResumeComplete message informing the base station of completion of connection establishment to switch to the RRC connected mode and switch to the RRC connected mode (4h-70).

In step 4h-60, the base station checks whether downlink data to the terminal exists, and if there is no downlink data and it is necessary to send the terminal to the RRC idle mode for a predetermined reason, 4h -75 procedures can be performed. The predetermined reasons may be reasons such as insufficient resources in the network, the terminal context is no longer valid, or there are too many RRC deactivation mode terminals in the current cell. In the above, the base station may send the terminal to the RRC idle mode by sending an RRCConnectionReject message or an RRCConnectionRelease message to the terminal (4h-75). In the above, the RRCConnectionReject message or the RRCConnectionRelease message may include indications instructing the UE to transition from the RRC deactivation mode to the RRC idle mode.

The next-generation mobile communication system can coexist with the existing LTE system and can support different cells. The LTE system supports a technology called light connection to save the battery of the terminal and support fast connection of the terminal, and the next-generation mobile communication system supports the RRC deactivation mode to save the battery of the terminal and support fast connection of the terminal . The light connection technology is very similar to managing a terminal in a lightly connected mode in a network and managing a terminal in an RRC deactivation mode in a next-generation mobile communication system, and may be considered the same mode and may perform the same operation. However, since the lightly connected mode and the RRC deactivation mode are handled in different radio access schemes, different parts may exist in operation.

Various scenarios may exist when implementing and deploying a next-generation mobile communication system. 4I is a diagram illustrating an example in which a next-generation mobile communication system and an LTE system coexist.

4I is a diagram illustrating one deployment scenario in which a next-generation mobile communication system and an LTE system coexist in the present invention.

In FIG. 4I, cells 4i-05 supported by the next-generation mobile communication system (NR) may always support the RRC deactivation mode. In addition, the LTE system may include cells 4i-10 that do not support the lightly connected mode and cells 4i-15 that support the lightly connected mode. Depending on the deployment scenario of the network, even in the next-generation mobile communication system, it may be divided into cells supporting the RRC deactivation mode and cells not supporting the RRC mode. In the deployment scenario shown in FIG. 4I , the RRC deactivation mode terminal may move cells supported by the next-generation mobile communication system and cells supported by the LTE system. Therefore, in order to support the mobility between different radio access methods of the RRC deactivation mode terminal, the following mobility support procedure between different radio access methods is proposed.

FIG. 4j is a diagram illustrating a procedure for supporting mobility of a terminal in an RRC deactivation mode (lightly connected mode) when a terminal accessing a cell supported by the LTE system moves to a cell supported by the next-generation mobile communication system in the present invention. to be.

In FIG. 4j , the terminal is connected to a cell supported by a base station (eNB) of the LTE system in RRC connected mode to transmit and receive data (4j-10). In step 4j-15, the LTE base station may transmit the terminal in a lightly connected mode or an RRC deactivation mode for a predetermined reason. The predetermined reason may be a reason for determining that there is no data transmission/reception between the terminal and the network for a certain period of time or the transmission resource of the base station is insufficient, or that the terminal is determined as a terminal with a high probability of transmitting and receiving data again in the near future. In the above, if the LTE base station decides to switch the terminal to the lightly connected mode or RRC deactivation mode, it transmits an RRCConnectionSuspend or RRCConnectionReconfiguration message or a newly defined RRC message to the terminal so that the terminal transitions from the RRC connected mode to the lightly connected mode or RRC deactivation mode. can direct The message may include an indication for transition to the lightly connected mode, RAN Paging Area information, a terminal identifier, security setting information (eg, NCC, NexthopChainingCounter), and the like. In the above, the LAN paging area setting information may be composed of two types of cell lists (cell list 1 and cell list 2). In the above, the first cell list (cell list 1) represents a list of cells supporting the RRC deactivation mode in the next-generation mobile communication system, and the second cell list (cell list 2) supports light connection (LC) in LTE. Displays a list of cells. Also, in the above, two terminal identifiers may be configured, the first terminal identifier may be used to establish a connection in the next-generation mobile communication system, and the second terminal identifier may be used to establish a connection in the LTE system. In the RRC message 4j-20, one terminal identifier that can be commonly used in the next-generation mobile communication system and the LTE system may be set. There may be coordination between the LTE system and the next-generation mobile communication system to allocate the list of cells and UE identifiers. That is, by sharing information on cell identifiers and information on terminal identifiers in different frightening access system systems, the information can be allocated to terminals of each system.

Upon receiving the RRC message (4j-20), the terminal may transition to and move to the lightly connected mode (4j-25). The lightly connected mode terminal can perform cell reselection while moving, and when there is no suitable cell for the previously accessed LTE system, it can attempt to connect to a cell supported by the next-generation mobile communication system. There is (4j-30). In the above case, when uplink data is generated, a paging message is received from the base station, control signaling to be transmitted to the uplink occurs, or the LAN paging area needs to be updated or the tracking area needs to be updated. , you can try to connect to the network. In the above, the UE may check the system information of the cell supported by the next-generation mobile communication system (4j-35) and check whether the cell supports the RRC deactivation mode. The cell may transmit an indicator of whether RRC deactivation is supported by including in the system information. If all cells supported by the next-generation mobile communication system always support the RRC deactivation mode, there is no need to broadcast whether the RRC deactivation mode is supported in the system information. As described above, when the terminal waits in a cell supported by the next-generation mobile communication system, the terminal may monitor paging from a CN (Core Network) and a paging from a fixed base station/RAN/AN (Access Network). The different pagings may be distinguished by an indicator or an identifier included in the paging message. For example, when the terminal identifier (resume ID) or the first terminal identifier is included in the paging message, it may be determined that the paging is from a fixed base station/RAN/AN (Access Network), such as IMSI, S-TMSI, etc. When the identifier is included, it may be determined as paging from a CN (Core Network).

The UE first checks whether the RRC deactivation mode is supported in a cell supported by the next-generation mobile communication system. And if the cell supports the RRC deactivation mode and there is a predetermined reason for the terminal to establish a connection to the network (for example, uplink data has been generated, or a paging message has been received from the base station, or a control signal to be transmitted through the uplink) If ring occurs, LAN paging area needs to be updated, or tracking area needs to be updated) and if the cell is included in the first cell list, RRC connection resumption configuration as described in FIGS. 4G and 4H The procedure may be performed including the first terminal identifier (4j-45). In addition, a new first terminal identifier and LAN paging area information may be set through the setting procedure.

And if the cell supports the RRC deactivation mode, if there is no reason for the terminal to establish a connection to the network, and the cell is included in the first cell list, the terminal does not take any action and While monitoring paging and paging from a fixed base station/RAN/AN (Access Network), the RRC deactivation mode may be maintained (4j-55).

And if the cell supports the RRC deactivation mode and the cell is not included in the first cell list, the LAN paging area update procedure as described in FIG. 4H may be performed including the first terminal identifier ( 4j-45).

And if the cell does not support the RRC deactivation mode, a general RRC connection establishment procedure as described with reference to FIG. 4f may be performed (4j-50).

4K is a diagram illustrating a procedure for supporting mobility of a terminal in an RRC deactivation mode (lightly connected mode) when a terminal accessing a cell supported by the next-generation mobile communication system moves to a cell supported by the LTE system in the present invention. to be.

In FIG. 4K , the terminal is connected to a cell supported by a base station (gNB) of a next-generation mobile communication system in RRC connected mode to transmit and receive data (4k-10). In step 4k-15, the next-generation mobile communication system base station may transmit the terminal in a lightly connected mode or an RRC deactivation mode for a predetermined reason. The predetermined reason may be a reason for determining that there is no data transmission/reception between the terminal and the network for a certain period of time or the transmission resource of the base station is insufficient, or that the terminal is determined as a terminal with a high probability of transmitting and receiving data again in the near future. In the above, if the LTE base station decides to switch the terminal to the lightly connected mode or RRC deactivation mode, it transmits an RRCConnectionSuspend or RRCConnectionReconfiguration message or a newly defined RRC message to the terminal so that the terminal transitions from the RRC connected mode to the lightly connected mode or RRC deactivation mode. can direct The message may include an indication for transition to the lightly connected mode, RAN Paging Area information, a terminal identifier, security setting information (eg, NCC, NexthopChainingCounter), and the like. In the above, the LAN paging area setting information may be composed of two types of cell lists (cell list 1 and cell list 2). In the above, the first cell list (cell list 1) represents a list of cells supporting the RRC deactivation mode in the next-generation mobile communication system, and the second cell list (cell list 2) supports light connection (LC) in LTE. Displays a list of cells. Also, in the above, two terminal identifiers may be configured, the first terminal identifier may be used to establish a connection in the next-generation mobile communication system, and the second terminal identifier may be used to establish a connection in the LTE system. In the RRC message 4k-20, one terminal identifier that can be commonly used in the next-generation mobile communication system and the LTE system may be set. There may be coordination between the LTE system and the next-generation mobile communication system to allocate the list of cells and UE identifiers. That is, by sharing information on cell identifiers and information on terminal identifiers in different frightening access system systems, the information can be allocated to terminals of each system.

Upon receiving the RRC message (4k-20), the UE may transition to and move to the RRC deactivation mode (4k-25). The lightly connected mode terminal can perform cell reselection while moving, and when a cell suitable for the next-generation mobile communication system to which it was previously accessed does not exist, it can attempt to connect to a cell supported by the LTE system. Yes (4k-30). In the above case, when uplink data is generated, a paging message is received from the base station, control signaling to be transmitted to the uplink occurs, or the LAN paging area needs to be updated or the tracking area needs to be updated. , you can try to connect to the network. In the above, the UE may check system information of a cell supported by the LTE system (4k-35) and check whether the cell supports light connection. The cell may transmit an indicator of whether or not light connection is supported in system information. As described above, when the terminal waits in a cell supported by the LTE system, the terminal may monitor paging from a CN (Core Network) and a paging from a fixed base station/RAN/AN (Access Network). The different pagings may be distinguished by an indicator or an identifier included in the paging message. For example, when the terminal identifier (resume ID) or the second terminal identifier is included in the paging message, it may be determined that the paging is from a fixed base station/RAN/AN (Access Network), such as IMSI, S-TMSI, etc. When the identifier is included, it may be determined as paging from a CN (Core Network).

The UE first checks whether light connection is supported in a cell supported by the LTE system. And if the cell supports light connection and there is a predetermined reason for the terminal to establish a connection to the network (for example, uplink data has been generated, or a paging message has been received from the base station, or control signaling to be transmitted through the uplink) occurs, when it is necessary to update the LAN paging area or to update the tracking area) and if the cell is included in the second cell list, the RRC connection resumption establishment procedure as described in FIGS. 4G and 4H may be performed including the second terminal identifier (4k-45). In addition, a new second terminal identifier and LAN paging area information may be set through the setting procedure.

And if the cell supports light connection, if there is no reason for the terminal to establish a connection to the network, and if the cell is included in the second cell list, the terminal does not take any action and paging from a CN (Core Network) It is possible to maintain the lightly connected mode while monitoring the paging from the and fixed base station / RAN / AN (Access Network) (4k-55).

And, if the cell supports light connection and the cell is not included in the second cell list, the LAN paging area update procedure as described in FIG. 4H may be performed including the second terminal identifier (4k). -45).

And if the cell does not support light connection, a general RRC connection establishment procedure as described in FIG. 4f may be performed (4k-50).

4L is a diagram illustrating an operation of a terminal supporting mobility of an RRC deactivation mode/Lightly connected mode terminal in different radio access schemes in the present invention.

In FIG. 4L, the UE in the RRC deactivation mode/Lightly connected mode (41-01) may perform a cell reselection process while moving (41-10). Then, it is checked whether the selected cell is an LTE cell or a next-generation mobile communication system cell through the cell reselection process (4l-15).

If the cell selected above is a next-generation mobile communication system cell, the condition is checked and a corresponding operation is performed as follows (4l-20).

If the condition 1-1 is satisfied in the above, the terminal performs operation 1-1 (41-25).

If the condition 1-2 is satisfied in the above, the terminal performs operation 1-2 (41-30).

If the condition 1-3 is satisfied in the above, the terminal performs operation 1-3 (41-35).

If conditions 1-4 are satisfied in the above, the terminal performs operations 1-4 (41-40).

In the 1-1 condition, if the cell supports the RRC deactivation mode and there is a predetermined reason for the terminal to establish a connection to the network (for example, uplink data is generated or a paging message is received from the base station, When control signaling to be transmitted to the uplink occurs, when it is necessary to update the LAN paging area or to update the tracking area), and when the cell is included in the first cell list (41-25) ).,

In the above, condition 1-2 indicates that the cell supports the RRC deactivation mode, there is no predetermined reason for the terminal to establish a connection to the network and the cell is included in the first cell list (41-30),

In the above, the 1-3 condition indicates that the cell supports the RRC deactivation mode and the cell is not included in the first cell list (41-35),

In the above, conditions 1-4 indicate a case in which the cell does not support the RRC deactivation mode (41-40).

In the above, operation 1-1 indicates that the RRC connection resumption establishment procedure as described in FIGS. 4G and 4H is performed including the first UE identifier (a new first UE identifier and LAN paging through the setting procedure) area information can be set) (4l-25),

In the above, operation 1-2 indicates that the UE maintains the RRC deactivation mode while monitoring paging from CN (Core Network) and paging from fixed base station/RAN/AN (Access Network) without taking any action (41) -30),

In the above, operations 1-3 indicate that the LAN paging area update procedure as described in FIG. 4H is performed including the first terminal identifier (41-35),

In the above, operations 1-4 indicate that a general RRC connection establishment procedure as described with reference to FIG. 4f is performed (41-40).

If the selected cell is an LTE cell, the condition is checked as follows and a corresponding operation is performed (41-45).

If the condition 2-1 above is satisfied, the terminal performs operation 2-1 (41-50).

If the condition 2-2 is satisfied in the above, the terminal performs operation 2-2 (41-55).

If the condition 2-3 is satisfied in the above, the terminal performs operation 2-3 (41-60).

If condition 2-4 is satisfied in the above, the terminal performs operation 2-4 (41-65).

In the 1-1 condition, if the cell supports light connection and there is a predetermined reason for the terminal to establish a connection to the network (eg, uplink data is generated, or a paging message is received from the base station, or the uplink When control signaling to be sent to the link occurs, when it is necessary to update the LAN paging area or to update the tracking area) and the cell is included in the second cell list (41-50) ,

In the above, condition 1-2 indicates that the cell supports light connection, there is no predetermined reason for the terminal to establish a connection to the network, and the cell is included in the second cell list (41-55),

In the above, the 1-3 condition indicates that the cell supports light connection and the cell is not included in the second cell list (41-60),

In the above, condition 1-4 indicates that the cell does not support light connection (41-65).

In the above, operation 1-1 indicates that the RRC connection resumption establishment procedure as described in FIGS. 4G and 4H is performed including the second UE identifier (a new second UE identifier and LAN paging through the setting procedure) area information can be set) (4l-50),

In the above, operation 1-2 indicates that the terminal maintains a lightly connected mode while monitoring paging from a CN (Core Network) and a paging from a fixed base station/RAN/AN (Access Network) without taking any action (4l -55),

In the above, operations 1-3 indicate that the LAN paging area update procedure as described in FIG. 4H is performed including the second terminal identifier (41-60),

In the above, operations 1-4 indicate that a general RRC connection establishment procedure as described with reference to FIG. 4f is performed (41-65).

4M shows the structure of a terminal to which an embodiment of the present invention can be applied.

Referring to the drawings, the terminal includes a radio frequency (RF) processing unit 4m-10, a baseband processing unit 4m-20, a storage unit 4m-30, and a control unit 4m-40. .

The RF processing unit 4m-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processing unit 4m-10 up-converts the baseband signal provided from the baseband processing unit 4m-20 into an RF band signal, transmits it through an antenna, and receives an RF band signal received through the antenna. down-converts to a baseband signal. For example, the RF processing unit 4m-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), and the like. can In the figure, only one antenna is shown, but the terminal may include a plurality of antennas. Also, the RF processing unit 4m-10 may include a plurality of RF chains. Furthermore, the RF processing unit 4m-10 may perform beamforming. For the beamforming, the RF processing unit 4m-10 may adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. Also, the RF processing unit may perform MIMO, and may receive multiple layers when performing MIMO operation. The RF processing unit 4m-10 may perform receive beam sweeping by appropriately setting a plurality of antennas or antenna elements under the control of the controller, or adjust the direction and beam width of the receive beam so that the receive beam is coordinated with the transmit beam. have.

The baseband processing unit 4m-20 performs a function of converting a baseband signal and a bit stream according to a physical layer standard of the system. For example, when transmitting data, the baseband processing unit 4m-20 generates complex symbols by encoding and modulating a transmitted bit stream. Also, when receiving data, the baseband processing unit 4m-20 restores a received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 4m-10. For example, in the case of orthogonal frequency division multiplexing (OFDM), when transmitting data, the baseband processing unit 4m-20 encodes and modulates a transmission bit stream to generate complex symbols, and convert the complex symbols to subcarriers. After mapping to , OFDM symbols are constructed through inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit 4m-20 divides the baseband signal provided from the RF processing unit 4m-10 into OFDM symbol units, and sends them to subcarriers through a fast Fourier transform (FFT) operation. After reconstructing the mapped signals, the received bit stream is reconstructed through demodulation and decoding.

The baseband processing unit 4m-20 and the RF processing unit 4m-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 4m-20 and the RF processing unit 4m-10 may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit 4m-20 and the RF processing unit 4m-10 may include a plurality of communication modules to support a plurality of different radio access technologies. In addition, at least one of the baseband processor 4m-20 and the RF processor 4m-10 may include different communication modules to process signals of different frequency bands. For example, the different radio access technologies may include an LTE network, an NR network, and the like. In addition, the different frequency bands may include a super high frequency (SHF) (eg, 2.5 GHz, 5 GHz) band and a millimeter wave (eg, 60 GHz) band.

The storage unit 4m-30 stores data such as a basic program, an application program, and setting information for the operation of the terminal. The storage unit 4m-30 provides stored data according to the request of the control unit 4m-40.

The controller 4m-40 controls overall operations of the terminal. For example, the control unit 4m-40 transmits and receives signals through the baseband processing unit 4m-20 and the RF processing unit 4m-10. In addition, the control unit 4m-40 writes and reads data in the storage unit 4m-40. To this end, the controller 4m-40 may include at least one processor. For example, the controller 4m-40 may include a communication processor (CP) that controls for communication and an application processor (AP) that controls an upper layer such as an application program.

Figure 4n shows a block configuration of the TRP in a wireless communication system to which an embodiment of the present invention can be applied.

As shown in the figure, the base station includes an RF processing unit 4n-10, a baseband processing unit 4n-20, a backhaul communication unit 4n-30, a storage unit 4n-40, and a control unit 4n-50. is comprised of

The RF processing unit 4n-10 performs a function for transmitting and receiving a signal through a wireless channel, such as band conversion and amplification of the signal. That is, the RF processor 4n-10 up-converts the baseband signal provided from the baseband processor 4n-20 into an RF band signal, transmits it through an antenna, and receives the RF band signal through the antenna. downconverted to a baseband signal. For example, the RF processing unit 4n-10 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is shown in the drawing, the first access node may include a plurality of antennas. Also, the RF processing unit 4n-10 may include a plurality of RF chains. Furthermore, the RF processing unit 4n-10 may perform beamforming. For the beamforming, the RF processing unit 4n-10 may adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. The RF processing unit may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 4n-20 performs a function of converting a baseband signal and a bit stream according to the physical layer standard of the first radio access technology. For example, when transmitting data, the baseband processing unit 4n-20 generates complex symbols by encoding and modulating a transmitted bit stream. Also, upon data reception, the baseband processing unit 4n-20 restores a received bit stream by demodulating and decoding the baseband signal provided from the RF processing unit 4n-10. For example, in the OFDM scheme, when transmitting data, the baseband processing unit 4n-20 generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then IFFT OFDM symbols are constructed through operation and CP insertion. Also, upon data reception, the baseband processor 4n-20 divides the baseband signal provided from the RF processor 4n-10 into OFDM symbol units, and restores signals mapped to subcarriers through FFT operation. After that, the received bit stream is restored through demodulation and decoding. The baseband processing unit 4n-20 and the RF processing unit 4n-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 4n-20 and the RF processing unit 4n-10 may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

The communication unit 4n-30 provides an interface for performing communication with other nodes in the network.

The storage unit 4n-40 stores data such as a basic program, an application program, and setting information for the operation of the main station. In particular, the storage unit 4n-40 may store information on a bearer assigned to an accessed terminal, a measurement result reported from the accessed terminal, and the like. In addition, the storage unit 4n-40 may store information serving as a criterion for determining whether to provide or stop multiple connections to the terminal. In addition, the storage unit 4n-40 provides stored data according to the request of the control unit 4n-50.

The controller 4n-50 controls overall operations of the main station. For example, the control unit 4n-50 transmits and receives signals through the baseband processing unit 4n-20 and the RF processing unit 4n-10 or through the backhaul communication unit 4n-30. In addition, the control unit 4n-50 writes and reads data in the storage unit 4n-40. To this end, the controller 4n-50 may include at least one processor.

Methods according to the embodiments described in the claims or specifications of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium are configured to be executable by one or more processors in an electronic device (device). One or more programs include instructions for causing an electronic device to execute methods according to embodiments described in a claim or specification of the present invention.

Such programs (software modules, software) include random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable ROM (EEPROM: Electrically Erasable Programmable Read Only Memory), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or any other form of It may be stored in an optical storage device or a magnetic cassette. Alternatively, it may be stored in a memory composed of a combination of some or all thereof. In addition, each configuration memory may be included in plurality.

In addition, the program is transmitted through a communication network consisting of a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. It may be stored on an attachable storage device that can be accessed. Such a storage device may be connected to a device implementing an embodiment of the present invention through an external port. In addition, a separate storage device on the communication network may be connected to the device performing the embodiment of the present invention.

In the specific embodiments of the present invention described above, elements included in the invention are expressed in the singular or plural according to the specific embodiments presented. However, the singular or plural expression is appropriately selected for the situation presented for convenience of description, and the present invention is not limited to the singular or plural element, and even if the element is expressed in plural, it is composed of the singular or singular. Even an expressed component may be composed of a plurality of components.

Meanwhile, although specific embodiments have been described in the detailed description of the present invention, various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments and should be defined by the claims described below as well as the claims and equivalents.

Claims (12)

A method performed by a terminal in a communication system, comprising:
Receiving, from a base station, a message for transitioning the state of the terminal from a radio resource control (RRC) connected state to an RRC deactivation state, wherein the message is configured for each of the data radio bearers (DRBs) related to the RRC deactivation state including access prohibition information, and the DRBs are set in an access stratum (AS) of the terminal;
when access is triggered in the RRC deactivation state, determining whether the access is prohibited based on access prohibition information configured for a DRB related to the access; and
if the access is not prohibited, performing the access to the base station. According to claim 1,
The method further comprising the step of receiving system information including prohibition information for each prohibition category from the base station in the RRC idle state. According to claim 1,
In the RRC deactivation state, the context of the terminal is stored in the terminal. 3. The method of claim 2,
Determining whether the access is prohibited comprises:
and when the access prohibition information is not applied to the access, determining whether the access is prohibited based on prohibition information included in the system information. 3. The method of claim 2,
The prohibition category corresponds to at least one of an access class, a terminal type, a service type, a call type, an application type, and a signal type. 3. The method of claim 2,
The prohibition information includes prohibited information related to emergency services,
Method, characterized in that the priority of the prohibition information related to the emergency service is set to the highest. In a terminal in a communication system,
transceiver; and
connected to the transceiver,
Receives a message from the base station for transitioning the state of the terminal from a radio resource control (RRC) connected state to an RRC deactivation state, and the message is an access established for each of the data radio bearers (DRBs) related to the RRC deactivation state Including prohibition information, the DRBs are set in the access stratum (AS) of the terminal,
When the access is triggered in the RRC deactivation state, determining whether the access is prohibited based on access prohibition information set for the DRB related to the access,
and a control unit configured to perform the access to the base station when the access is not prohibited. 8. The method of claim 7,
The control unit is
A terminal, characterized in that receiving system information including prohibition information for each prohibition category from the base station in the RRC idle state. 8. The method of claim 7,
In the RRC deactivation state, the context of the terminal is stored in the terminal. 9. The method of claim 8,
The control unit is
When the access prohibition information is not applied to the access, the terminal characterized in that it is determined whether the access is prohibited based on the prohibition information included in the system information. 9. The method of claim 8,
The prohibited category corresponds to at least one of an access class, a terminal type, a service type, a call type, an application type, and a signal type. 9. The method of claim 8,
The prohibition information includes prohibited information related to emergency services,
The terminal, characterized in that the priority of the prohibition information related to the emergency service is set to the highest.

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