KR20200085986A - Method and apparatus for controlling cell selection - Google Patents

Abstract

The present invention provides a cell selection control method. More particularly, according to an embodiment of the present invention, provided is a method which controls cell selection by setting a cellbarred information element of a master information block (MIB) transmitted on a PBCH of non-terrestrial network (NTN) to barred, so that a general terminal avoids the cell selection provided through the NTN, and an NTN terminal ignores the same.

Description

Method and apparatus for controlling cell selection}

The present invention relates to a method and apparatus for controlling cell selection/reselection of an idle mode or inactive mode terminal in a 5G NR-based non-terrestrial network.

According to an embodiment of the present invention, in a cell selection control method, a cell barred information element of a MIB transmitted on a PBCH of a non-terrestrial network (NTN) is set to barred, so that a general terminal selects a cell provided through the NTN. And the NTN terminal ignores this to provide a method for controlling cell selection.

1 is a diagram briefly showing the structure of an NR wireless communication system to which the present embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which the present embodiment can be applied.
3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for describing a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
5 exemplarily shows a synchronization signal block in a radio access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a view for explaining CORESET.
8 is a diagram illustrating an example of symbol level alignment for different SCSs to which the present embodiment can be applied.
9 is a diagram illustrating an example of an NTN scenario to which the present embodiment can be applied.
10 is a diagram showing the type of NTN platform to which the present embodiment can be applied.
11 is a diagram exemplarily showing a configuration of an NTN satellite beam to which the present embodiment can be applied.
12 is a diagram illustrating an example of an MIB information element to which the present embodiment can be applied.
13 is a diagram showing an example of an SIB1 information element to which the present embodiment can be applied.
14 is a diagram showing the configuration of a base station according to another embodiment.
15 is a diagram showing the configuration of a user terminal according to another embodiment.

Hereinafter, some embodiments of the present technology will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, the same components may have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the technical idea, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the technical idea, the detailed description may be omitted.

In addition, in describing components of the present embodiments, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, order, or number of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected to or connected to the other component, but different components between each component It should be understood that the "intervenes" may be, or each component may be "connected", "coupled" or "connected" through other components.

In addition, the terms and technical names used in the present specification are for describing specific embodiments, and the technical idea is not limited to the terms. The terms described below may be interpreted as meanings generally understood by those of ordinary skill in the technical field to which this technical idea belongs, unless otherwise defined. When the term is an incorrect technical term that does not accurately represent the technical idea, it should be understood as being replaced by a technical term that can be correctly understood by those skilled in the art. In addition, the general terms used in this specification should be interpreted as defined in the dictionary or in context before and after, and should not be interpreted as an excessively reduced meaning.

The wireless communication system in the present specification means a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, and a core network.

The embodiments disclosed below can be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments are code division multiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-electron frequency division multiple access (SC-FDMA). It can be applied to various wireless access technologies such as. CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented with wireless technologies such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA). IEEE 802.16m is an evolution of IEEE 802.16e, and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is part of evolved UMTS (E-UMTS) using evolved-UMTS terrestrial radio access (E-UTRA), adopts OFDMA in the downlink and SC- in the uplink. Adopt FDMA. As described above, the present embodiments may be applied to a currently disclosed or commercialized wireless access technology, or may be applied to a wireless access technology currently being developed or to be developed in the future.

Meanwhile, the terminal in the present specification is a comprehensive concept that refers to a device including a wireless communication module that performs communication with a base station in a wireless communication system. UEs in WCDMA, LTE, HSPA, and IMT-2020 (5G or New Radio) It should be interpreted as a concept including (User Equipment) as well as a mobile station (MS), a user terminal (UT), a subscriber station (SS), and a wireless device in GSM. In addition, the terminal may be a user portable device such as a smart phone depending on the type of use, or in a V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, or the like. Further, in the case of a machine type communication system, it may mean an MTC terminal, an M2M terminal, etc. equipped with a communication module so that the machine type communication is performed.

The base station or cell herein refers to an end that communicates with a terminal in terms of a network, Node-B (Node-B), evolved Node-B (eNB), gNode-B (gNB), Low Power Node (LPN), Sectors, sites, various types of antennas, BTS (Base Transceiver System), access points, points (e.g., transmission points, reception points, transmission/reception points), relay nodes (Relay Node) ), mega cell, macro cell, micro cell, pico cell, femto cell, remote radio head (RRH), radio unit (RU), small cell (small cell).

Since the various cells listed above have a base station that controls each cell, the base station can be interpreted in two ways. 1) a device that provides a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, or a small cell in relation to the wireless area, or 2) the wireless area itself. In 1), all devices that provide a predetermined wireless area are controlled by the same entity, or all devices that interact to configure the wireless area in a collaborative manner are instructed to the base station. Points, transmission/reception points, transmission points, reception points, and the like, according to a configuration method of a wireless area, are examples of base stations. In 2), the radio area itself, which receives or transmits a signal from the viewpoint of the user terminal or the neighboring base station, may be directed to the base station.

In this specification, a cell is a component carrier having a coverage of a signal transmitted from a transmission/reception point or a signal transmitted from a transmission/reception point, or a transmission/reception point itself. Can.

Uplink (Uplink, UL, or uplink) means a method of transmitting and receiving data to the base station by the terminal, downlink (Downlink, DL, or downlink) means a method of transmitting and receiving data to the terminal by the base station The downlink may refer to a communication or communication path from multiple transmission/reception points to a terminal, and the uplink may refer to a communication or communication path from a terminal to multiple transmission/reception points. At this time, in the downlink, the transmitter may be a part of multiple transmission/reception points, and the receiver may be a part of the terminal. In addition, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multiple transmission/reception points.

The uplink and downlink transmit and receive control information through control channels such as PDCCH (Physical Downlink Control CHannel), PUCCH (Physical Uplink Control CHannel), and PDSCH (Physical Downlink Shared CHannel), PUSCH (Physical Uplink Shared CHannel), etc. The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is also referred to as'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

In order to clarify the description, hereinafter, the technical idea is mainly described for a 3GPP LTE/LTE-A/NR (New RAT) communication system, but this technical feature is not limited thereto.

In 3GPP, after research on 4G (4th-Generation) communication technology, 5G (5th-Generation) communication technology is being conducted to meet the requirements of ITU-R's next-generation wireless access technology. Specifically, 3GPP is conducting research on new NR communication technologies that are separate from LTE-A pro and 4G communication technologies that have improved LTE-Advanced technology to meet the requirements of ITU-R with 5G communication technology. Both LTE-A pro and NR are expected to be submitted in 5G communication technology, but the following description will focus on NR for convenience of explanation.

The operating scenario in NR defined various operation scenarios by adding considerations for satellite, automobile, and new verticals in the existing 4G LTE scenario, and has an eMBB (Enhanced Mobile Broadband) scenario and high terminal density in terms of service. It is deployed in the range and supports the Massive Machine Communication (mmmTC) scenario that requires low data rate and asynchronous connection, and the Ultra Reliability and Low Latency (URLLC) scenario that requires high responsiveness and reliability and can support high-speed mobility. .

To satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, low latency technology, ultra-high-bandwidth (mmWave) support technology, and forward compatible technology are applied. In particular, in the NR system, various technical changes are proposed in terms of flexibility in order to provide forward compatibility. The main technical features will be described below with reference to the drawings.

<NR system general>

1 is a diagram briefly showing the structure of an NR system to which the present embodiment can be applied.

Referring to FIG. 1, the NR system is divided into a 5GC (5G Core Network) and an NR-RAN part, and the NG-RAN is controlled for a user plane (SDAP/PDCP/RLC/MAC/PHY) and user equipment (UE). It consists of gNB and ng-eNBs that provide a plane (RRC) protocol termination. The gNB interconnects or the gNB and ng-eNB are interconnected via an Xn interface. gNB and ng-eNB are each connected to 5GC through an NG interface. The 5GC may be configured to include an access and mobility management function (AMF) in charge of a control plane such as a terminal access and mobility control function and a user plane function (UPF) in charge of a control function in user data. The NR includes support for frequency bands below 6 GHz (FR1, Frequency Range 1) and frequency bands above 6 GHz (FR2, Frequency Range 2).

gNB means a base station providing NR user plane and control plane protocol termination to the terminal, and ng-eNB means a base station providing E-UTRA user plane and control plane protocol termination to the terminal. The base station described in this specification should be understood as a meaning encompassing gNB and ng-eNB, and may be used in a sense to refer to a gNB or ng-eNB separately if necessary.

<NR wave form, pneumatics and frame structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with multiple input multiple output (MIMO), and has the advantage of being able to use a receiver of low complexity with high frequency efficiency.

On the other hand, in the NR, the demands for data rate, delay rate, and coverage for each of the three scenarios described above are different from each other, so it is necessary to efficiently satisfy the requirements for each scenario through the frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

값이 2의 지수 값으로 사용되어 지수적으로 변경된다.Specifically, the NR transmission numerology is determined based on sub-carrier spacing (CP) and cyclic prefix (CP), based on 15khz as shown in Table 1 below.

The value is used as an exponent value of 2 and is changed exponentially.

Subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR numerology can be divided into 5 types according to the subcarrier spacing. This is different from that in which the subcarrier spacing of LTE, which is one of 4G communication technologies, is fixed at 15khz. Specifically, the subcarrier interval used for data transmission in NR is 15, 30, 60, and 120 khz, and the subcarrier interval used for synchronization signal transmission is 15, 30, 12, and 240 khz. In addition, the extended CP applies only to the 60khz subcarrier spacing. On the other hand, the frame structure (frame structure) in the NR is defined as a frame having a length of 10ms composed of 10 subframes (subframe) having the same length of 1ms. One frame can be divided into 5 ms half frames, and each half frame includes 5 subframes. In the case of a 15khz subcarrier interval, one subframe is composed of one slot, and each slot is composed of 14 OFDM symbols.

2 is a diagram for explaining a frame structure in an NR system to which the present embodiment can be applied.

Referring to FIG. 2, the slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length of the slot may vary depending on the subcarrier interval. For example, in the case of a numerology with a 15 khz subcarrier spacing, the slot is 1 ms long and is configured to have the same length as the subframe. On the contrary, in the case of a neuromerlage having a 30 khz subcarrier spacing, a slot is composed of 14 OFDM symbols, but may have two slots in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined with a fixed time length, and the slot is defined by the number of symbols, so that the time length may vary according to the subcarrier interval.

Meanwhile, the NR defines a basic unit of scheduling as a slot, and also introduces a mini-slot (or sub-slot or non-slot based schedule) to reduce transmission delay in a radio section. When a wide subcarrier interval is used, the length of one slot is inversely shortened, and thus transmission delay in a wireless section can be reduced. The mini-slot (or sub-slot) is for efficient support for the URLLC scenario and can be scheduled in units of 2, 4, and 7 symbols.

In addition, unlike LTE, uplink and downlink resource allocation is defined as a symbol level in one slot. In order to reduce HARQ delay, a slot structure capable of directly transmitting HARQ ACK/NACK in a transmission slot has been defined, and this slot structure is referred to as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in Rel-15. In addition, a common frame structure configuring FDD or TDD frames is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which downlink symbols and uplink symbols are combined are supported. In addition, NR supports that data transmissions are scheduled to be distributed over one or more slots. Accordingly, the base station may inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station may indicate the slot format by indicating the index of a table configured through RRC signaling using SFI, and dynamically indicate through DCI (Downlink Control Information) or statically or quasi-statically through RRC. It might be.

<NR Physical Resources>

With regard to physical resources in the NR, antenna ports, resource grids, resource elements, resource blocks, and bandwidth parts are considered. Can be.

The antenna port is defined such that a channel carrying a symbol on the antenna port can be inferred from a channel carrying another symbol on the same antenna port. If the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC/QCL (quasi co-located or quasi co-location). Here, the wide-range characteristics include one or more of delay spread, doppler spread, frequency shift, average received power, and received timing.

3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.

Referring to FIG. 3, a resource grid may exist according to each neuromerging because the NR supports a plurality of neuromerging on the same carrier. In addition, the resource grid may exist according to the antenna port, subcarrier spacing, and transmission direction.

A resource block consists of 12 subcarriers and is defined only on the frequency domain. Further, a resource element is composed of one OFDM symbol and one subcarrier. Therefore, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, the NR defines "Point A", which serves as a common reference point for the resource block grid, a common resource block, and a virtual resource block.

4 is a diagram for describing a bandwidth part supported by a radio access technology to which the present embodiment can be applied.

Unlike LTE, where the carrier bandwidth is fixed at 20Mhz in NR, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in the NR, as shown in FIG. 4, a terminal can be used by designating a bandwidth part within a carrier bandwidth. In addition, the bandwidth part is associated with one neurology and consists of a subset of consecutive common resource blocks, and can be dynamically activated with time. A maximum of 4 bandwidth parts are configured in the uplink and the downlink, respectively, and data is transmitted and received using the bandwidth part activated at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tunning is prevented between downlink and uplink operation. For this, the bandwidth part of the downlink and the uplink is configured in pairs so that the center frequency can be shared.

<NR initial connection>

In NR, a terminal accesses a base station and performs a cell search and random access procedure to perform communication.

Cell search is a procedure in which a terminal synchronizes with a cell of a corresponding base station, obtains a physical layer cell ID, and acquires system information using a synchronization signal block (SSB) transmitted by the base station.

5 exemplarily shows a synchronization signal block in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 5, the SSB is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, and 3 OFDM symbols and a PBCH spanning 240 subcarriers, respectively.

The terminal receives the SSB by monitoring the SSB in the time and frequency domain.

SSB can be transmitted up to 64 times in 5 ms. Multiple SSBs are transmitted with different transmission beams within 5 ms time, and the terminal performs detection by assuming that SSBs are transmitted every 20 ms period when viewed based on a specific one beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to four SSB beams can be transmitted below 3 GHz, and up to eight different beams can be transmitted using up to eight different beams in the frequency band from 3 to 6 GHz and up to 64 in the frequency band above 6 GHz.

Two SSBs are included in one slot, and the starting symbol and the number of repetitions in the slot are determined according to the subcarrier interval.

Meanwhile, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the SS of the conventional LTE. That is, the SSB may be transmitted out of the center of the system band, and when supporting broadband operation, a plurality of SSBs may be transmitted on the frequency domain. Accordingly, the terminal monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and the synchronization raster, which are the center frequency location information of the channel for initial access, are newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, and thus supports fast SSB search of the UE. Can.

The terminal may acquire MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the UE to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information on the location of the first DM-RS symbol on the time domain, information for the UE to monitor SIB1 (for example, SIB1 neuromerging information, information related to SIB1 CORESET, search space information, PDCCH Related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 pneumatic information is equally applied to messages 2 and 4 of the random access procedure for accessing the base station after the terminal completes the cell search procedure.

The aforementioned RMSI means System Information Block 1 (SIB1), and SIB1 is broadcast periodically (ex, 160 ms) in the cell. SIB1 includes information necessary for the UE to perform the initial random access procedure, and is periodically transmitted through the PDSCH. In order to receive SIB1, the UE must receive pneumatic information used for SIB1 transmission and control resource set (CORESET) information used for scheduling of SIB1 through PBCH. The UE identifies scheduling information for SIB1 using SI-RNTI in CORESET, and acquires SIB1 on the PDSCH according to the scheduling information. The remaining SIBs except SIB1 may be periodically transmitted or may be transmitted according to the terminal's request.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when the cell search is completed, the UE transmits a random access preamble for random access to the base station. The random access preamble is transmitted through PRACH. Specifically, the random access preamble is transmitted to the base station through PRACH composed of continuous radio resources in a specific slot that is periodically repeated. Generally, a contention-based random access procedure is performed when a UE initially accesses a cell, and a non-competition-based random access procedure is performed when random access is performed for beam failure recovery (BFR).

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), UL grant (uplink radio resource), temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier) and TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, a random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes the information included in the random access response, and performs scheduled transmission to the base station. For example, the terminal applies TAC and stores a temporary C-RNTI. In addition, by using UL Grant, data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In this case, information capable of identifying the terminal should be included.

Finally, the terminal receives a downlink message for contention resolution.

<NR CORESET>

The downlink control channel in NR is transmitted in a control resource set (CORESET) having a length of 1 to 3 symbols, and transmits uplink/downlink scheduling information, slot format index (SFI), and transmit power control (TPC) information. .

Thus, in order to secure the flexibility of the system, NR introduced the concept of CORESET. CORESET (Control Resource Set) means a time-frequency resource for a downlink control signal. The UE may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A QCL (Quasi CoLocation) assumption for each CORESET was established, and this is used for the purpose of informing the characteristics of the analog beam direction in addition to delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by the conventional QCL.

7 is a view for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth in one slot, and CORESET on a time domain may consist of up to 3 OFDM symbols. In addition, CORESET is defined as a multiple of 6 resource blocks from the frequency domain to the carrier bandwidth.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration to receive additional configuration information and system information from the network. After establishing a connection with the base station, the UE may configure by receiving one or more CORESET information through RRC signaling.

<NR MIMO and Beam operation>

In NR, beam management related technology, which is an analog beam forming evolution technology, was added, and MIMO codebook/feedback technology, which is a conventional digital beam forming technology, was developed.

In the case of analog beamforming, the beam operation-related technology that forms the optimal beam pair between the base station and the terminal through base station/terminal beam sweeping transmission and beam repetitive transmission, etc., quickly overcomes the deterioration of the serving beam quality and uses a new beam pair It can be largely classified into beam failure recovery techniques for forming.

Initial beam establishment

The procedure for forming the best beam pair between the initial base station and the terminal, that is, initial beam establishment is performed in the initial access procedure. During the initial cell search, the UE may acquire some of a plurality of SSBs each composed of different downlink beams transmitted from the base station in chronological order.

The UE selects an optimal beam based on the obtained SSBs, and transmits a random access preamble associated with the optimal beam to the base station. Specifically, different SSB time indices are associated with different random access channel time/frequency occasions and/or other preamble sequence.

In the case where one SSB is associated with two or more random access time/frequency occasions, the frequency is prioritized as priority, time is first in one slot, and time is preferred between the two slots. do.

Accordingly, the base station can identify the optimal beam through the random access preamble associated with the optimal beam. As a result, the base station and the terminal form an initial optimal beam pair.

Beam adjustment

Since relatively wide beams were used in the initial beamforming, after initial beamforming, the base station and the terminal perform beam adaptation with a relatively narrow beam. In addition, beam adaptation is performed even when movement or rotation of the terminal occurs.

Beam adaptation can be divided into downlink beam adaptation and uplink beam adaptation.

Downlink beam adaptation can be divided into downlink transmitter-side beam adjustment and downlink receiver-side beam adjustment.

For example, downlink transmission side beam adaptation will be described as an example. When the base station transmits two or more downlink signals (for example, CSI-RS or SSB), the UE performs measurements on them and reports the result to the base station. The base station determines the optimal beam according to the report result from the terminal, and the base station and the terminal form a beam pair based on the optimal beam.

When a base station and a terminal form a beam pair using CSI-RS, the base station sequentially transmits two or more and up to four CSI-RSs each composed of different beams to the terminal. The UE measures each CSI-RS, for example, L1-RSRP and reports the result to the base station.

The report result shows the indication information of up to 4 CSI-RSs, the measured L1-RSRP for the strong beam (L1-RSRP for the strong beam), the difference between the L1-RSRP of the remaining beams and the L1-RSRP of the strongest beam. It can contain values.

Beam indication and TCI

NR supports a beam indication function. For example, the base station notifies the UE of the beams used in the PDSCH and the PDCCH using configuration information and TCI (Transmission Configuration Indicator).

For example, the UE may be configured with up to 64 candidate TCI states. For PDCCH beam indication, a subset of M configured candidate TCI states is allocated by higher layer signaling, for example RRC signaling, and by MAC signaling, the base station dynamically announces a specific TCI state.

For PDSCH beam indication, when the PDCCH-PDSCH timing offset (scheduling offset) included in the PDCCH is greater than N symbols, the scheduling allocation DCI (for example, 3 bits) explicitly indicates the TCI state for PDSCH transmission. When the PDCCH-PDSCH timing offset (scheduling offset) included in the PDCCH is equal to or smaller than the N symbol, the UE assumes that the TCI state of the PDCCH indicated by MAC signaling and the TCI state for PDSCH transmission are the same as described above. .

Beam failure recovery

The UE may detect whether the error probability for the PDCCH exceeds a specific set value or a beam failure based on a measurement result of quality of a specific RS.

When detecting a beam failure, the UE selects an optimal candidate beam according to measurement of CSI-RSs or SSBs, for example, L1-RSRP measurement, and makes a beam-recovery request to the base station. send.

The beam recovery request is performed through a contention-free random access channel. First, the UE transmits a random access preamble associated with the optimal beam in the same way as the initial beam formation. And the base station sends a response to this request.

The terminal monitors the response, and upon receiving the response, beam recovery is completed.

In this specification, frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals, various messages related to NR (New Radio) Can be interpreted as meaning used in the past or present or various meanings used in the future.

NR (New Radio)

NR conducted in 3GPP is a wireless access technology that can satisfy various QoS requirements required for each segmented and detailed usage scenario as well as an improved data rate compared to LTE. In particular, as a representative usage scenario of NR, enhancement mobile BroadBand (eMBB), massive MTC (mMTC) and Ultra Reliable and Low Latency Communications (URLLC) have been defined, and flexible frame compared to LTE as a method to satisfy the requirements for each usage scenario. structure is provided. The NR frame structure supports multiple subcarrier-based frame structures. The default SCS is 15 kHz, and 15 kHz*2 ^μ supports a total of 5 types of SCS. 8 shows an example of symbol level alignment for different SCSs. As shown in FIG. 8, it can be seen that the slot length varies depending on numerology. That is, it can be seen that the shorter the slot length, the larger the SCS. In addition, the number of OFDM symbols constituting the slot in the NR and the y value are determined to have a value of y=14 regardless of the SCS value in the case of a normal CP. Accordingly, an arbitrary slot is composed of 14 symbols, and according to the transmission direction of the slot, all symbols are used for DL transmission, or all symbols are used for UL transmission, or DL portion + (gap) + It may be used in the form of a UL portion. In addition, in a certain numerology (or SCS), a mini-slot consisting of fewer symbols than the slot is defined, and based on this, a short length time-domain scheduling interval for transmitting/receiving uplink/downlink data is established, or slot aggregation Through this, a long-length time-domain scheduling interval for transmitting/receiving uplink/downlink data may be configured. In particular, when transmitting/receiving latency-critical data such as URLLC, when scheduling is performed in a slot unit based on 1 ms (14 symbols) defined in a numerology-based frame structure with a small SCS value such as 15 kHz, it is difficult to satisfy latency requirements. To this end, for this, a mini-slot consisting of fewer OFDM symbols than the corresponding slot can be defined to define scheduling for latency critical data such as the corresponding URLLC.

NR supports the following structures on the time axis. Here, the difference from the existing LTE is that the basic scheduling unit has been changed to a slot in NR. In addition, regardless of subcarrier-spacing, the slot is composed of 14 OFDM symbols. On the other hand, it supports a non-slot structure composed of 2,4,7 OFDM symbols, which are smaller scheduling units. The non-slot structure can be used as a scheduling unit for URLLC services.

RRC idle terminal and RRC inactive terminal process

In the NR, the RRC IDLE terminal and the RRC INACTIVE terminal perform PLMN selection, cell selection, and cell reselection processes. When the terminal turns on the switch, PLMN is selected by the NAS. For PLMN selection, the AS searches for available PLMNs at the request of the NAS of the terminal and reports them to the NAS. The UE scans all RF channels in the NR band according to the capability to find available PLMNs. On each carrier, the UE searches its strongest cell and reads its system information to find the PLMN to which the cell belongs. If the UE can read one or more PLMN identifiers in the strongest cell, if the high quality condition (e.g., the RSRP value measured for an NR cell is greater than or equal to -100 dBm) is satisfied, each found PLMN Is reported to the NAS as a high quality PLMN. The NAS can provide a list of equivalent PLMNs that the AS will use for cell selection and cell reselection.

When the UE selects a PLMN, a cell selection procedure is performed to select a suitable cell of the PLMN to camp on. The UE selects one suitable cell based on the measurement and cell selection criteria.

Cell selection is performed by one of the following procedures.

a) Initial cell selection (no prior knowledge of which RF channels are NR carriers):

One. The UE shall scan all RF channels in the NR bands according to its capabilities to find a suitable cell.

2. On each carrier frequency, the UE need only search for the strongest cell.

3. Once a suitable cell is found, this cell shall be selected.

b) Cell selection by leveraging stored information:

One. This procedure requires stored information of carrier frequencies and optionally also information on cell parameters from previously received measurement control information elements or from previously detected cells.

2. Once the UE has found a suitable cell, the UE shall select it.

3. If no suitable cell is found, the initial cell selection procedure in a) shall be started.

When camping on one cell, the UE periodically searches for a better cell according to the cell reselection criteria. If a better cell is found, that cell is selected. The absolute priority of different NR frequencies or inter-RAT frequencies may be provided to the terminal. (Absolute priorities of different NR frequencies or inter-RAT frequencies may be provided to the UE in the system information, in the RRCRelease message, or by inheriting from another RAT at inter-RAT cell (re)selection.)

Non-Terrestrial Network (NTN)

Non-Terrestrial Network (Non-Terrestrial Network) refers to a network or a segment of a network using RF resources mounted on a satellite (or UAS (Unmanned Aircraft System platform). FIG. 9 shows an example of a typical NTN scenario.

NTN can be implemented in a number of ways:

-Scenario A: Transparent GEO (NTN beam foot print fixed on earth)

-Scenario B: Regenerative GEO (NTN beam foot print fixed on earth)

-Scenario C1: Transparent LEO (NTN beam foot print fixed on earth)

-Scenario C2: Transparent LEO (NTN beam foot print moving on earth)

-Scenario D1: Regenerative LEO (NTN beam foot print fixed on earth)

-Scenario D2: Regenerative LEO (NTN beam foot print moving on earth)

Here, the transparent payload or regenerative payload is defined as follows.

-A transparent payload: Radio Frequency filtering, Frequency conversion and amplification. Hence, the waveform signal repeated by the payload is un-changed;

-A regenerative payload: Radio Frequency filtering, Frequency conversion and amplification as well as demodulation/decoding, switch and/or routing, coding/modulation. This is effectively equivalent to having all or part of base station functions (e.g. gNB) on board the satellite (or UAS platform).

The satellite (or UAS platform) generate beams typically generate several beams over a given service area. bounded by its field of view.) The beam's footprint is typically elliptical. 10 shows the type of NTN platform and the footprint size of a typical beam.

As in scenarios C2 and D2, when the NTN beam foot print moves on the earth, that is, when the satellite beam moves with the satellite, it can be assumed that the link between the cell and the base station does not change. For example, when a satellite beam transmitted through a corresponding satellite is configured in one-to-one connection with one PCI, a cell having the corresponding PCI moves on the earth as time passes.

For convenience of description, hereinafter, a beam generated from a satellite platform in NTN is referred to as a satellite beam. This is for convenience of description and may be replaced with any other term.

On the other hand, the earth fixed beam used in other scenarios means that the satellite steers the beam to a fixed point on the earth using a beamforming technique during the visibility time of the satellite. . In the case of the steerable beam, even if the satellite moves, the foot print of the satellite beam can be fixed on the earth.

When implementing an NTN scenario based on NR technology, any satellite beam, satellite, or satellite cell cannot be seen separately from a normal NR cell from a terminal point of view to efficiently provide NTN by recycling NR specifications as much as possible (Satellite beams) , satellites or satellite cells are not considered to be visible from UE perspective. For example, PCI, SSB, and CSI-RS standardized in NR can be viewed from a terminal perspective. Accordingly, even in the case of a normal NR terminal, a cell provided through NTN can be selected or reselected. However, in a typical mobile communication network (3G, 4G/LTE or 5G/NR), which is generally composed of a terrestrial network, the transmission power of a general terminal may not be sufficient to transmit a signal to a high altitude satellite. In this case, even if the terminal camps on one cell, it may be difficult for the terminal to access a network provided through a satellite. For example, if the UE attempts to register the network after selecting one cell, it may experience a RACH failure. After multiple RACH failures, the cell to camp on can be changed. This can cause unnecessary delays and power consumption.

When configuring an NTN network based on NR technology, the UE may not be able to distinguish between a normal NR cell provided through a terrestrial network and an NTN cell provided through a non-terrestrial network. Accordingly, a normal NR terminal can select or reselect a cell provided through NTN. In this case, even if the terminal camps on one cell, there is a problem in that the terminal fails to access a network provided through a satellite and may generate unnecessary delay and power consumption.

The present invention, devised to solve the above problems, proposes a method and apparatus for effectively providing cell selection or reselection provided through a non-terrestrial network.

There is no explicit definition for one cell in the conventional NR standard. However, PCI (Physical Cell Identifier) is used in the NR standard. Within the frequency span of one carrier, multiple SSBs can be transmitted. The PCIs of the SSBs need not be unique. However, when one SSB is associated with one RMSI, the SSB corresponds to one individual cell having one unique NR cell global identifier. This SSB is called a CD-SSB. (Within the frequency span of a carrier, multiple SSBs can be transmitted.The PCIs of those SSBs do not have to be unique, ie different SSBs can have different PCIs.However, when an SSB is associated with an RMSI, the SSB corresponds to A individual cell, which has a unique NCGI.Such an SSB is referred to as a Cell-Defining SSB (CD-SSB).A PCell is always associated to a CD-SSB located on the synchronization raster.) At most, a serving cell is associated with one single SSB. In the conventional NR standard, SSBs were serviced by beams in which NR-PSS, NR-SSS and NR-PBCH are transmitted, and a plurality of SSBs in one cell share the same PCI. And SSB was transmitted by TDM method by beam sweeping.

One satellite beam is one beam generated from one satellite platform, and one earth footprint or radio coverage is formed by one satellite beam. For example, the radio coverage may be an area capable of receiving a signal having a value that is as large as a threshold value from the largest signal of the beam. It is assumed that it is not considered that a terminal can distinguish a satellite beam, a satellite, or a satellite cell that is distinguished from an NR cell in order to efficiently provide the NTN by recycling the NR standard as much as possible. 11 shows an example of the configuration of a satellite beam when constructing an NTN based on NR. First, as in option a, multiple (e.g. L) satellite beams may be configured to have the same PCI. The linkage between PCI and SSB can be implemented in a manner similar to NR. For example, one SSB may be provided per PCI. Alternatively, a plurality of SSBs may be provided in one PCI. A plurality of SSBs may be provided in a TDM manner by one satellite beam. Through this, it has the same cell identification information, but it is possible to distinguish the satellite beam and provide beam mobility. On the other hand, NTN has a large delay between the terminal and the satellite, so the effect may be limited when using multiple SSBs in a TDM scheme. Therefore, if a plurality of SSBs are provided for the same PCI, it can be configured such that different satellite beams have different SSBs by providing the FDM scheme. In this case, satellite beams providing different SSBs for the same PCI can be provided through different MIB information (one or more information elements) and different SIB1s (one or more information elements) to distinguish each frequency. have. Through this, although the same cell identification information is provided, it is possible to distinguish the satellite beam and provide beam mobility. Alternatively, satellite beams providing different SSBs for the same PCI (one or more information elements) may have the same MIB information (one or more information elements) provided through different SIB1s. Alternatively, satellite beams providing different SSBs for the same PCI may be provided through the same MIB (one or more information elements) and the same SIB1 (one or more information elements). Or, satellite beams providing different SSBs for the same PCI may have different MIB information (one or more information elements) but provide the same SIB1 (one or more information elements).

As another example, option b may be configured to have one PCI per satellite beam. The coverage of NTN is larger than that of high frequency based terrestrial NR, so it is not necessary to provide multiple SSBs for the same PCI. Therefore, one satellite beam can be configured as one cell. Through this, different satellite beams can be configured to have different PCI (or NGCI). The linkage between PCI and SSB can be implemented in a manner similar to NR. For example, one SSB may be provided per PCI. Alternatively, a plurality of SSBs may be provided in one PCI. A plurality of SSBs may be provided in a TDM manner by one satellite beam. In the above description, an example of linking one PCI to one or more SSBs has been described, but this is only for convenience of description, and any scenario in which one cell is divided into a plurality of satellite beams having the same PCI and transmitted In the present invention can be applied.

When configuring an NTN network based on NR technology as described above, the UE may not be able to distinguish between a normal NR cell provided through a terrestrial network and an NTN cell provided through a non-terrestrial network. Accordingly, a normal NR terminal can select or reselect a cell provided through NTN. In this case, even if the terminal camps on one cell, there is a problem in that the terminal fails to access a network provided through a satellite and may generate unnecessary delay and power consumption. Also, the NTN NR terminal may not be able to distinguish a network provided through a satellite. Accordingly, a method for preventing an existing general terminal from accessing a network through a cell provided through NTN may be required. Alternatively, a method for distinguishing cells provided through the NTN may be required for the NTN terminal. To solve this, the following methods may be used individually or in combination of any methods.

1) By setting the cellbarred information element of MIB to barred, the normal terminal is set to avoid the selection of the cell provided through NTN, and the NTN terminal is set to ignore it.

The MIB transmitted on the PBCH includes cell baring status information and physical layer information essential for receiving additional system information. For example, MIB provides a parameter for monitoring a PDCCH for scheduling a PDSCH carrying SIB1 to a UE and a parameter for cell barring status. 12 shows an example of an MIB information element.

In the case of a general terminal, when the terminal receives the MIB, if the parameter (cellbarred) for the cell barring state is set to barred in the obtained MIB, the terminal is not allowed to select/reselect the cell. Therefore, it is possible to prevent a normal terminal from accessing the network through a cell provided through NTN. However, an NTN capable terminal, for example, a terminal capable of performing network access through a cell provided through NTN, selects/reselects the cell even if a cell barred parameter is set to barred in the MIB. Can be allowed. The NTN capable terminal may consider the cell as a candidate during the cell selection/reselection procedure. This is when the terminal configuration information (for example, random access identity) of the NTN capable terminal is configured with a specific value or when any information included in the MIB or SIB1 of the cell is indicated with a specific value for the NTN capable terminal. During the select/reselect procedure, the cell can be considered a candidate (or not barred).

For example, in FIG. 12, the spare bit information of MIB may be used as indication information for the cell-baring state of the NTN capable terminal. Through this, the NTN capable terminal may be allowed to select/reselect the cell even if the cellbarred parameter is set to barred, but if the spare bit is set to a specific value, it may not be allowed to select/reselect the cell. For convenience of description, it is indicated as an NTN capable terminal, but it can represent a terminal having any terminal capability related to NTN access. Also, for convenience of explanation, a method of combining spare bits of MIB has been described, but it is also seen that parameters in MIB or SIB1 or any SIB (SIB for other SI or NTN or any SIB other than MIB/SIB1) are used. It is included in the scope of the invention. Additional embodiments will be described below.

2) By setting the cellReservedForOtherUse information element to reserved, the normal terminal is set to avoid the selection of the cell provided through the NTN, and the NTN terminal is set to ignore it.

SIB1 contains information required for scheduling and initial access of other system information blocks. 13 shows an example of the SIB1 information request. Among them, cellAccessRelatedInfo indicates cell access-related information for a cell, and is composed of a PLMN identifier list (plmn-IdentityList) and information indicating whether a cell is reserved for another purpose (cellReservedForOtherUse) as a detail element. In the case of a general terminal, when information indicating whether a cell is reserved for another use is indicated as reserved, the cell state is processed as barred. Accordingly, the terminal is not allowed to select/reselect the cell. Therefore, it is possible to prevent a normal terminal from accessing the network through a cell provided through NTN. However, an NTN capable terminal may be allowed to select/reselect the cell even if information indicating whether the cell is reserved for another use is set to reserved. The NTN capable terminal may consider the cell as a candidate during the cell selection/reselection procedure. This is when the terminal configuration information (for example, random access identity) of the NTN capable terminal is configured with a specific value or when any information included in the MIB or SIB1 of the cell is indicated with a specific value for the NTN capable terminal. During the select/reselect procedure, the cell can be considered a candidate (or not barred or not reserved). Or NTN capable terminal when the other SI of the cell (for example, SIB for NTN or any SIB other than MIB/SIB1) includes any SIB information for the NTN/NTN terminal, or the terminal is an NTN capable terminal Upon receiving SI scheduling information for SIB for the cell, it is possible to consider the cell as a candidate (or not barred or not reserved) during the cell selection/reselection procedure.

Meanwhile, information for indicating information indicating whether a cell is reserved for another use for an NTN capable terminal may be added to MIB or SIB1 or other SI. Through this, it can be used as indication information for indicating whether a cell is reserved for another purpose for an NTN capable terminal.

3) Set the cellReservedForOperatorUse information element to reserved, so that the general terminal avoids selecting the cell provided through the NTN, and the NTN terminal sets it to be ignored.

The PLMN identifier list (plmn-IdentityList) information included in the above-mentioned cellAccessRelatedInfo is used to configure a set of PLMN identifier information elements. Each of these elements contains one or more PLMN identifiers in a list and additional information associated with the PLMNs (The PLMN-IdentityList is used to configure a set of PLMN-IdentityInfo elements.Each of those elements contains a list of one or more PLMN Identities and additional information associated with those PLMNs). The PLMN identifier list (plmn-IdentityList) information includes detailed information (cellReservedForOperatorUse) indicating whether the cell is reserved for operator use (per PLMN). In the case of a general terminal, when information indicating whether the cell is reserved for operator use for any PLMN is indicated as reserved, the cell state is processed as barred. Accordingly, the terminal is not allowed to select/reselect the cell. Therefore, it is possible to prevent a normal terminal from accessing the network through a cell provided through NTN. However, the NTN capable terminal may be allowed to select/reselect the cell even if information indicating whether the cell is reserved for operator use for any PLMN is set to reserved. The NTN capable terminal may consider the cell as a candidate during the cell selection/reselection procedure. This is when the terminal configuration information (for example, random access identity) of the NTN capable terminal is configured with a specific value or when any information included in the MIB or SIB1 of the cell is indicated with a specific value for the NTN capable terminal. During the select/reselect procedure, the cell can be considered a candidate (or not barred or not reserved). Or NTN capable terminal when the other SI of the cell (for example, SIB for NTN or any SIB other than MIB/SIB1) includes any SIB information for the NTN/NTN terminal, or the terminal is an NTN capable terminal Upon receiving SI scheduling information for SIB for the cell, it is possible to consider the cell as a candidate (or not barred or not reserved) during the cell selection/reselection procedure.

Meanwhile, for an NTN capable terminal, information for indicating information indicating whether a cell is reserved for operator use for any PLMN may be added to MIB or SIB1 or other SI. Through this, for the NTN capable terminal, it can be used as indication information for indicating whether a cell is reserved for operator use for any PLMN.

Hereinafter, another embodiment that can be used independently or in combination with the above-described methods will be described.

For example, a specific PLMN ID may be fixed/specified as a value (or range value) for NTN. For example, the PLMN ID or MNC or MCC can be fixed/assigned to a specific value. Through this, the terminal can identify the cell as a cell provided through NTN. For a general terminal, the fixed/designated PLMN ID value is set to forbidden PLMN, so that the cell is not selected/reselected. Or, through this, the NTN capable terminal may attempt to access the cell by dividing the cell into an NTN cell. Or, forbidden PLMN or a lower priority value for the corresponding PLMN may be set to indicate NAS or AS signaling.

For another example, a specific value of any information element included in SIB1 (or MIB) may be fixed/specified as a value (or range value) for NTN. As an example, an arbitrary parameter value included in ue-TimersAndConstants can be fixed/specified as a specific value. Through this, the terminal can identify the cell as a cell provided through NTN. For a general terminal, when the corresponding parameter has a fixed/designated value, it is possible not to select/reselect the cell. Or, through this, the NTN capable terminal may attempt to access the cell by dividing the cell into an NTN cell. As another example, an arbitrary parameter value included in the integrated access baring information (uac-BarringInfo) may be fixed/designated as a specific value. Through this, the terminal can identify the cell as a cell provided through NTN. Alternatively, for a general terminal, when the corresponding parameter has a fixed/designated value, the cell is considered to be barred and the cell cannot be selected/reselected. Or, through this, the NTN capable terminal may attempt to access the cell by dividing the cell into an NTN cell.

For another example, any new information element for identifying and identifying an NTN cell included in SIB1 (or MIB) from any NR cell may be defined. Through this, the terminal can identify the cell as a cell provided through NTN. For a general terminal, when the corresponding parameter is set and instructed, the cell may not be selected/reselected. Or, through this, the NTN capable terminal may attempt to access the cell by dividing the cell into an NTN cell.

As described above, the present invention has an effect of allowing a general terminal or an NTN capable terminal to effectively perform cell selection or reselection provided through a non-terrestrial network.

14 is a diagram showing the configuration of a base station 1000 according to another embodiment.

Referring to FIG. 14, the base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

In the cell selection control method required to perform the above-described present invention, the control unit 1010 sets the cellbarred information element of the MIB transmitted on the PBCH of a non-terrestrial network (NTN) to barred, thereby allowing the general terminal to The selection of the cell provided through the NTN is avoided, and the NTN terminal is ignored to control the overall operation of the base station 1000 according to the method for controlling cell selection.

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary to perform the present invention described above.

15 is a diagram showing the configuration of a user terminal 1100 according to another embodiment.

Referring to FIG. 15, the user terminal 1100 according to another embodiment includes a receiver 1110, a controller 1120, and a transmitter 1130.

The reception unit 1110 receives downlink control information, data, and messages from a base station through a corresponding channel.

In addition, the control unit 1120 in the cell selection control method required to perform the above-described present invention, by setting the cellbarred information element of the MIB transmitted on the PBCH of a non-terrestrial network (NTN) to barred general terminal Is to avoid the selection of the cell provided through the NTN, the NTN terminal is to ignore it to control the operation of the overall user terminal 1100 according to the method of controlling the cell selection.

The transmitter 1130 transmits uplink control information, data, and a message to the base station through a corresponding channel.

The above-described embodiments can be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps, configurations, and parts that are not described in order to clearly reveal the technical idea among the embodiments may be supported by the above-described standard documents. In addition, all terms disclosed in this specification may be described by standard documents disclosed above.

The above-described embodiments may be implemented through various means. For example, the embodiments can be implemented by hardware, firmware, software, or a combination thereof.

For implementation by hardware, the method according to the embodiments includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, the method according to the embodiments may be implemented in the form of an apparatus, procedure, or function that performs the functions or operations described above. The software code can be stored in a memory unit and driven by a processor. The memory unit is located inside or outside the processor, and can exchange data with the processor by various known means.

In addition, the terms “system”, “processor”, “controller”, “component”, “module”, “interface”, “model”, and “unit” described above generally refer to computer-related entity hardware, hardware and software. It can mean a combination, software or running software. For example, the above-described components may be, but are not limited to, a process, processor, controller, control processor, entity, execution thread, program and/or computer driven by a processor. For example, both an application running on a controller or processor and a controller or processor can be a component. One or more components can be in a process and/or thread of execution, and the components can be located on one machine or deployed to more than one machine.

The above description and the accompanying drawings are merely illustrative of the technical idea of the present invention, and those skilled in the art can combine, separate, and replace configurations without departing from the essential characteristics of the present technology. Various modifications and variations such as changes will be possible. Therefore, the embodiments disclosed in this specification are not intended to limit the technical spirit, but to explain the scope of the technical spirit by the embodiments. The scope of protection of this technical spirit should be interpreted by the claims, and all technical spirits within the equivalent scope should be interpreted as being included in the scope of the present specification.

Claims (1)

In the cell selection control method,
The cellbarred information element of the MIB transmitted on the PBCH of a non-terrestrial network (NTN) is set to barred so that the general terminal avoids selection of the cell provided through the NTN, and the NTN terminal ignores it. By controlling the cell selection method.

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