Terminals, base stations, and communication methods

Abstract

This terminal comprises: a reception unit that receives system information including second information pertaining to a cell in which first information pertaining to a sub-group at one or a plurality of paging opportunities is transmitted; and a control unit that, when in an idle state or a non-active state, controls monitoring of a PDCCH with respect to first downlink control information including the first information, on the basis of the second information. If the second information is set in a last cell indicating the cell that has received an RRC release message, the control unit monitors the PDCCH with respect to the first downlink control information including the first information in a cell in which the RRC release message has been received. If the second information is not set, the control unit monitors the PDCCH with respect to the first downlink control information including the first information in the visited cell.

Description

Cross - reference to related applications

[0001] This application is based on Japanese Patent Application No. 2022 - 001580 filed on January 7, 2022, claims the benefit of its priority, and all the contents of that patent application are incorporated herein by reference.

Technical Field

[0002] This disclosure relates to a terminal, a base station, and a communication method.

Background Art

[0003] In the Third Generation Partnership Project (3GPP), an international standardization organization, Release 15 of New Radio (NR), which is the fifth generation (5G) Radio Access Technology (RAT), has been standardized as a successor to Long Term Evolution (LTE), the 3.9 - generation RAT, and LTE - Advanced, the 4 - generation RAT (for example, Non - Patent Document 1). LTE and / or LTE - Advanced are also called Evolved Universal Terrestrial Radio Access (E - UTRA).

Prior Art Documents

Patent Documents

[0004]

Non - Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In NR, terminals monitor Downlink Control Information (DCI) (hereinafter referred to as "Paging DCI," also called "Second Downlink Control Information"), which includes information regarding scheduling of downlink shared channels (e.g., Physical Downlink Shared Channels: PDSCH) that transmit paging messages and / or information regarding short messages, during a predetermined period called a Paging Occasion (PO), and can receive paging messages and / or short messages based on the detected Paging DCI. Currently, 3GPP is considering notifying terminals of paging information at one or more POs (hereinafter referred to as "Paging Early Indication (PEI) information" or "First Information") and controlling terminal operations at the PO based on said PEI information.

[0006] One of the objectives of this disclosure is to provide a terminal, base station, and communication method that can appropriately control the transmission and reception of PEI information.

[0007] A terminal according to one aspect of the present disclosure includes a receiving unit that receives system information including second information relating to a cell to which first information relating to a subgroup in one or more paging opportunities is transmitted, and a control unit that controls the monitoring of PDCCH for first downlink control information including the first information based on the second information when the control unit is idle or inactive, wherein the control unit monitors PDCCH for the first downlink control information including the first information in the cell that received the RRC release message if the second information is set to the last cell indicating the cell that received the RRC release message, and monitors PDCCH for the first downlink control information including the first information in the cell where the control unit is located if the second information is not set.

[0008] According to this disclosure, the transmission and reception of PEI information can be appropriately controlled. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an example of the overview of the wireless communication system according to this embodiment. [Figure 2] Figure 2 shows an example of a PO according to this embodiment. [Figure 3] Figure 3 shows an example of the relationship between PEI-O and PO according to this embodiment. [Figure 4] Figure 4 is a sequence diagram showing an example of a processing procedure for an idle terminal 10. [Figure 5] Figure 5 is a sequence diagram showing an example of the processing procedure for an inactive terminal. [Figure 6] Figure 6 shows an example of a specification change (part 1) in the 3GPP specification (TS38.304). [Figure 7] Figure 7 shows an example of a specification change (part 1) in the 3GPP specification (TS38.331). [Figure 8] Figure 8 shows an example of specification changes (part 2) in the 3GPP specification (TS38.304). [Figure 9] Figure 9 shows an example of specification changes (part 2) in the 3GPP specification (TS38.331). [Figure 10] Figure 10 shows an example of specification changes in the 3GPP specification (TS38.413). [Figure 11] Figure 11 shows an example of specification changes in the 3GPP specification (TS38.413). [Figure 12] Figure 12 shows an example of specification changes in the 3GPP specification (TS38.413). [Figure 13] Figure 13 shows an example of specification changes in the 3GPP specification (TS38.413). [Figure 14] Figure 14 shows an example of specification changes in the 3GPP specification (TS38.423). [Figure 15] Figure 15 shows an example of specification changes in the 3GPP specification (TS38.423). [Figure 16] FIG. 16 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to this embodiment. [Figure 17] FIG. 17 is a diagram showing an example of the functional configuration of the terminal according to this embodiment. [Figure 18] FIG. 18 is a diagram showing an example of the functional block configuration of the base station according to this embodiment. [Figure 19] FIG. 19 is a diagram showing an example of the functional configuration of the core network according to this embodiment.

Mode for Carrying Out the Invention

[0010] Hereinafter, this embodiment will be described with reference to the accompanying drawings. For ease of understanding the description, the same reference numerals are given to the same components in each drawing as much as possible, and redundant descriptions are omitted.

[0011] FIG. 1 is a diagram showing an example of the outline of the wireless communication system according to this embodiment. As shown in FIG. 1, the wireless communication system 1 may include a terminal 10, a base station 20, and a core network 30. Note that the numbers of the terminal 10 and the base station 20 shown in FIG. 1 are merely examples and are not limited to the numbers shown.

[0012] Wireless communication system 1 is a system that communicates in accordance with Radio Access Technology (RAT) defined by 3GPP. While fifth-generation RATs such as NR are envisioned as the radio access technology to which wireless communication system 1 conforms, it is not limited to this. One or more RATs may be used, such as fourth-generation RATs like LTE and LTE-Advanced, sixth-generation and later RATs, or non-3GPP RATs like Wi-Fi®. Furthermore, wireless communication system 1 may also communicate in accordance with radio access technology defined by standards-setting organizations other than 3GPP (e.g., the Institute of Electrical and Electronics Engineers (IEEE), the Internet Engineering Task Force (IETF)).

[0013] The terminal 10 is a device corresponding to a terminal (e.g., UE (User Equipment)) defined in the 3GPP specification. The terminal 10 is, for example, a predetermined terminal or device such as a smartphone, a personal computer, a vehicle, an in-vehicle terminal, an in-vehicle device, a stationary device, an IoT device such as a Telematics control unit (TCU), a sensor, etc. The terminal 10 may be referred to as a User Equipment (UE), a Mobile Station (MS), a User Terminal, a Radio apparatus, a subscriber terminal, an access terminal, etc. Also, the terminal 10 may be a so-called Reduced capability (RedCap) terminal, and may be, for example, an industrial wireless sensor, a video surveillance camera, a wearable device, etc. The terminal 10 may be mobile or fixed. The terminal 10 is configured to be able to communicate using one or more RATs such as NR, LTE, LTE-Advanced, Wi-Fi (registered trademark), etc. Note that the terminal 10 is not limited to the terminal defined in the 3GPP specification, and may be a terminal compliant with the standard specifications defined by other standard-setting organizations. Also, the terminal 10 does not have to be a terminal compliant with the standard specifications.

[0014] Base station 20 is a device equivalent to a base station (e.g., gNodeB (gNB) or eNB) as defined in the 3GPP specification. Base station 20 forms one or more cells C and communicates with terminal 10 using these cells. Cell C may be interchangeably referred to as a serving cell, carrier, component carrier (CC), etc. Cell C may also have a predetermined bandwidth. For example, base station 20 may communicate with terminal 10 using one or more cell groups. Each cell group may contain one or more cells C. Integrating multiple cells C within a cell group is called carrier aggregation. These multiple cells C may include a primary cell (PCell) or primary / secondary cell group (SCG) cell (PSCell) and one or more secondary cells (Secondary Cells (SCG)). Communicating with terminal 10 using two cell groups is also called dual connectivity. Furthermore, terminal 10 is not limited to base stations specified in the 3GPP specification, but may also be a terminal compliant with standards specified by other standards-setting organizations. Also, terminal 10 does not have to be a base station compliant with standards.

[0015] The base station 20 may also be called a gNodeB (gNB), en-gNB, Next Generation-Radio Access Network (NG-RAN) node, low-power node, Central Unit (CU), Distributed Unit (DU), gNB-DU, Remote Radio Head (RRH), Integrated Access and Backhaul / Backhauling (IAB) node, access point, etc. The base station 20 is not limited to a single node, but may consist of multiple nodes (for example, a combination of lower-level nodes such as DUs and higher-level nodes such as CUs).

[0016] The core network 30 is, for example, a fifth-generation core network (5G Core Network: 5GC) or a fourth-generation core network (Evolved Packet Core: EPC), but is not limited to these. Devices on the core network 30 (hereinafter also referred to as "core network devices") may perform mobility management such as paging and location registration of terminals 10. The core network devices may be connected to base stations 20 or terminals 10 via a predetermined interface (for example, S1 or NG interface).

[0017] The core network device may include, for example, at least one of the following: an Access and Mobility Management Function (AMF) that manages C-plane information (e.g., information related to access and mobility management, etc.) and a User Plane Function (UPF) that controls the transmission of U-plane information (e.g., user data).

[0018] In the wireless communication system 1, terminal 10 receives downlink (DL) signals from base station 20 and / or transmits uplink (UL) signals to base station 20. Terminal 10 is configured with one or more cells C, and at least one of the configured cells may be activated. The maximum bandwidth of each cell is, for example, 20 MHz or 400 MHz.

[0019] Furthermore, terminal 10 performs a cell search based on synchronization signals from base station 20 (e.g., Primary Synchronization Signal (PSS) and / or Secondary Synchronization Signal (SSS)). Cell search is a procedure in which terminal 10 obtains the synchronization of time and frequency in a cell and detects the identifier of that cell (e.g., physical layer cell ID).

[0020] Terminal 10 determines the search space set and / or control resource set (CORESET) based on the parameters included in the Radio Resource Control (RRC) message (hereinafter referred to as "RRC parameters"). The CORESET may consist of frequency domain resources (e.g., a predetermined number of resource blocks) and time domain resources (e.g., a predetermined number of symbols). The RRC parameters may also be called RRC information elements (IE), etc.

[0021] Terminal 10 monitors Downlink Control Information (DCI) transmitted via a downlink control channel (e.g., Physical Downlink Control Channel: PDCCH) within the search space set associated with CORESET. RRC messages may include, for example, RRC setup messages, RRC reconfiguration messages, RRC resume messages, RRC reestablishment messages, system information, etc. Hereinafter, the downlink control channel will be referred to as PDCCH, but other names may be used.

[0022] DCI monitoring is the process by which terminal 10 blindly decodes PDCCH candidates in the search space set using the expected DCI format. The number of bits in the DCI format (also called size, bit width, etc.) is predetermined or derived according to the number of bits in the fields included in the DCI format. Terminal 10 detects the DCI for itself based on the number of bits in the DCI format and a specific Radio Network Temporary Identifier (RNTI) used for scrambling the Cyclic Redundancy Check (CRC) bits (also called CRC parity bits) of the DCI format (hereinafter referred to as "CRC scrambling"). DCI monitoring is also called PDCCH monitoring or monitoring. The given period for performing DCI or PDCCH monitoring is also called a PDCCH monitoring occasion.

[0023] Terminal 10 monitors the PDCCH using a search space set during PDCCH monitoring opportunities and receives (or detects) DCIs that are CRC scrambled by a specific RNTI (e.g., P-RNTI, Cell(C)-RNTI, etc.). Terminal 10 controls the reception of downlink shared channels (e.g., Physical Downlink Shared Channel: PDSCH) and / or the transmission of uplink shared channels (e.g., Physical Uplink Shared Channel: PUSCH) that are scheduled using the DCI. Hereinafter, downlink shared channels and uplink shared channels will be referred to as PDSCH and PUSCH, but other names may be used.

[0024] A search space set is a collection of one or more search spaces, and may include a search space set used in common by one or more terminals 10 (hereinafter referred to as the "Common search space (CSS) set") and a terminal-specific search space set (UE-specific search space (USS) set). Terminal 10 receives information regarding the settings of each search space set and configures each search space set based on that information.

[0025] For example, terminal 10 may receive information regarding the configuration of a search space set for paging (hereinafter referred to as "paging search space") (hereinafter referred to as "paging search space configuration information," for example, the RRC parameter "pagingSearchSpace") and configure the paging search space (for example, Type2-PDCCH CSS set) based on this information. Terminal 10 may also detect DCIs that are CRC scrambled by a specific RNTI (for example, "Paging(P)-RNTI").

[0026] Terminal 10 receives paging messages via a PDSCH scheduled using DCI. Here, the information indicating P-RNTI may be set by a predetermined value. Hereafter, the paging DCI may be a DCI that is CRC scrambled by P-RNTI. The format of the DCI may be, for example, DCI format 1_0. Terminal 10 may also receive short messages based on the paging DCI.

[0027] The system information broadcast in cell C may include a Master Information Block (MIB) and / or one or more System Information Blocks (SIBs). The MIB is broadcast via a broadcast channel (e.g., a Physical Broadcast channel (PBCH)). MIB and SIB1 are also called Minimum System Information, and SIB1 is also called Remaining Minimum System Information (RMSI). SIBx other than SIB1 (x = any string such as 2, 3, ...) are also called Other System Information (OSI). SIB1 and SIBx other than SIB1 are broadcast via the PDSCH. SIB1 is cell-specific, and SIBx other than SIB1 may be cell-specific or area-specific, including one or more cells.

[0028] A block containing at least one of a synchronization signal, a PBCH, and a demodulation reference signal (DM-RS) for the PBCH is called a synchronization signal block (SSB). An SSB may also be called an SS / PBCH block, an SS block, etc. An SSB may consist of a predetermined number of symbols as time-domain resources (e.g., four consecutive symbols) and a predetermined number of subcarriers as frequency-domain resources (e.g., 240 consecutive subcarriers).

[0029] An SS burst set, which is a set of one or more SSBs, is transmitted at a predetermined period. An SS burst set may also be called an SS burst, etc. Each SSB within an SS burst set is identified by an index (hereinafter referred to as "SSB index"). In multi-beam operation, SSBs with different indices within an SS burst set may correspond to different beams and be transmitted by sequentially switching the beam direction through beam sweeping. In single-beam operation, an SSB (one or more SSBs) with a specific index within an SS burst set may be transmitted in all directions.

[0030] One or more Bandwidth Parts (BWPs) may be configured for a single cell C. A BWP may include a DL BWP (hereinafter referred to as "DL BWP") and / or a UL BWP (hereinafter referred to as "UL BWP"). A BWP may also include a cell-specific BWP (hereinafter referred to as "initial BWP") and a terminal 10-specific BWP (hereinafter referred to as "dedicated BWP"). An initial BWP is used for initial access and / or may be common to one or more terminals 10. An initial BWP may include an initial DL BWP (hereinafter referred to as "initial DL BWP") and an initial UL BWP (hereinafter referred to as "initial UL BWP"). A dedicated BWP is also called a "UE-specific BWP".

[0031] (paging) Paging is used for network-initiated connection setup when terminal 10 is idle or inactive. Paging is also used for transmitting short messages. Short messages may be used to instruct system information updates and / or for public warning systems (PWS). Short messages may also be sent regardless of the state of terminal 10. Examples of PWSs include earthquake and tsunami warning systems (ETWS) and commercial mobile alert systems (CMAS).

[0032] Here, the idle state is a state in which the RRC layer connection (hereinafter referred to as "RRC connection") between terminal 10 and base station 20 has not been established, and is also called RRC_IDLE, idle mode, RRC idle mode, etc. Terminal 10 in the idle state receives system information, short messages, and paging messages by monitoring the control channel in the cell it is located in. When the RRC connection is established, terminal 10 in the idle state transitions to the connected state.

[0033] Furthermore, the inactive state is a state in which the above-mentioned RRC connection is established but suspended, and is also called the RRC_INACTIVE state, inactive mode, RRC inactive mode, etc. Terminal 10 in the inactive state receives system information, short messages, and paging messages by monitoring the control channel in the cell in which it is located. Terminal 10 in the inactive state transitions to the connected state when the RRC connection is resumed, and transitions to the idle state when the RRC connection is released.

[0034] The connected state is the state in which the above-mentioned RRC connection is established, and is also called the RRC_CONNECTED state, connected mode, RRC connected mode, etc. Terminal 10 in the connected state sends and receives various data, including system information and short messages, in the cell in which it is located. Terminal 10 in the connected state transitions to the idle state when the RRC connection is released, and transitions to the inactive state when the RRC connection is temporarily suspended.

[0035] Idle and inactive terminals 10 perform cell selection and reside in the most suitable cell found. Furthermore, according to the cell re-selection criteria, if terminal 10 finds a cell that satisfies the criteria (a more suitable cell), it resides in that cell.

[0036] Furthermore, "being present in a region" can also be called "camping." For example, "being present in a cell" can also be called "camping on a cell." Additionally, a "present cell" can be called a "camping cell," a "synchronizing cell," a "serving cell," or a "cell set on terminal 10."

[0037] If the network (e.g., base station 20 and / or core network 30) needs to send a message to an idle terminal 10, it may send a short message or a paging message in all cells within the set of Tracking Areas (TAs) that include the cell where terminal 10 is located. Alternatively, if the network (e.g., base station 20 and / or core network 30) needs to send a message to an inactive terminal 10, it may send a paging message in all cells within the RAN Notification Area (RNA) where terminal 10 is located. The network (e.g., base station 20 and / or core network 30) may, for example, send a paging message in the cell where terminal 10 last established an RRC connection, and if there is no response from terminal 10 in that cell, it may send paging messages in other cells within the set of TAs or RNA.

[0038] Each TA (Terminal Adapter) is associated with one or more cells. TAs are identified by a Tracking Area Identifier (TAI). The core network 30 manages the registered areas of terminals 10 in units of sets of TAs.

[0039] When the core network 30 (e.g., AMF) performs a registration procedure with terminal 10, it assigns terminal 10 a TAI list that represents a set of TAs as the registration area. This TAI list includes at least the TAIs of the TAs corresponding to the cell where terminal 10 is located. If terminal 10's current TAI is not found in this TAI list, it performs a Mobility Registration Update Procedure to notify the core network 30 (e.g., AMF) that it has moved outside the TAI list (i.e., outside the registration area). Upon receiving this notification, the core network 30 updates terminal 10's TAI list.

[0040] An RNA covers one or more cells and is contained within a registration area (i.e., a set of TAs) in the core network 30. In other words, an RNA may be a subdivided area of ​​the registration area. An inactive terminal 10 can move within the area defined by the RNA without notifying the base station 20. If terminal 10 selects a cell that does not belong to the RNA defined for terminal 10 using the cell reselection procedure, it sends an RNA update (RAN-based notification area update) to base station 20. When base station 20 (also called "Last serving gnB") that instructed terminal 10 to transition to an inactive state receives a signal from the core network 30 regarding terminal 10, it performs paging in the cell corresponding to the RNA. Also, if the RNA includes cells from another base station 20 (also called a neighboring base station 20), base station 20 may send a RAN paging message to the other base station 20 to perform paging. Upon receiving the paging signal, the inactive terminal 10 resumes the RRC connection and transitions to a connected state.

[0041] Paging initiated by the core network 30 for idle terminals 10 may be called "CN paging." Paging initiated by the base station 20 for inactive terminals 10 may be called "RAN paging."

[0042] Terminal 10 performs discontinuous reception (DRX) to reduce power consumption. Specifically, terminal 10 performs PDCCH monitoring during paging occasions (POs) and can sleep during periods other than those POs.

[0043] A PO (Point of Partition) is a given period consisting of one or more time units (e.g., one or more symbols, one or more slots, or one or more subframes). A PO may consist of, for example, a set of one or more PDCCH monitoring opportunities. A PO may be provided at a predetermined period. A PO may be provided within a Paging Frame (PF). The Radio Frames (RFs) that make up a PF are predetermined time units (e.g., time units consisting of 10 subframes) and are identified by an identification number (hereinafter referred to as the "System Frame Number (SFN)"). One or more PFs may be provided within a DRX period. A DRX period is also called a paging cycle.

[0044] Terminal 10 may be configured by base station 20 with information regarding the paging settings in BWP (hereinafter referred to as "PCCH-Config"). PCCH-Config may include at least one of the following: information regarding the DRX period (hereinafter referred to as "PagingCycle"), information regarding the first PDCCH monitoring opportunity in a PO (hereinafter referred to as "firstPDCCH-MonitoringOccasionOfPO"), information indicating the number of PFs and / or time offsets in the paging cycle (hereinafter referred to as "nAndPagingFrameOffset"), information regarding the number of POs per PF (hereinafter referred to as "ns"), and information regarding the number of PDCCH monitoring opportunities per SSB in a PO (hereinafter referred to as "nrofPDCCH-MonitoringOccasionPerSSB-InPO"). PCCH-Config may also be cell-specific RRC parameters.

[0045] Terminal 10 determines the PF for terminal 10 based on at least one of the DRX period, the number of PFs within the DRX period, the time offset, and the identifier of terminal 10. Here, for example, terminal 10 may determine the SFNs that constitute the PF based on the following equation (1).

[0046] (Formula 1) (SFN+PF_offset) mod T = (T div N)*(UE_ID mod N) Here, T is the DRX period determined based on the above PagingCycle, N and PF_offset are the number of PFs in T and a predetermined offset, determined based on the above nAndPagingFrameOffset, and UE_ID is a value determined based on the identifier of terminal 10 (e.g., 5G S-Temporary Mobile Subscription Identifier (5G-S-TMSI)). PagingCycle may indicate, for example, 32, 64, 128, or 256 RFs. nAndPagingFrameOffset may indicate that a PF is placed for every x RF in T (e.g., x=1, 2, 4, 8, or 16) and / or a time offset.

[0047] Terminal 10 may determine the PO within the PF based on at least one of the ID of the search space used as the paging search space, the firstPDCCH-MonitoringOccasionOfPO, and the nrofPDCCH-MonitoringOccasionPerSSB-InPO. The PO may consist of, for example, S*X consecutive PDCCH monitoring opportunities (e.g., S*X consecutive symbols excluding UL symbols) from the time position indicated by firstPDCCH-MonitoringOccasionOfPO. Each PDCCH monitoring opportunity within the PO may consist of a predetermined number of symbols. firstPDCCH-MonitoringOccasionOfPO may indicate, for example, the time position of the first PDCCH monitoring opportunity within the PF (e.g., the position of a symbol). Note that S is the number of SSBs actually transmitted in the SS burst set, and X is the number of PDCCH monitoring opportunities per SSB within the PO.

[0048] Figure 2 shows an example of a PO according to this embodiment. As shown in Figure 2, PFs are placed every predetermined number of RFs (here, 8 RFs) within the DRX period (here, 32 RFs). Terminal 10 may determine its own PF (here, PF#2) based on its UE_ID, for example, using formula 1 above. For example, in Figure 2, PF#2 for terminal 10 contains two POs, but is not limited to this; the number of POs per PF can be one or more.

[0049] Terminal 10 controls the establishment of a connection with the network side (e.g., base station 20 and / or core network 30) based on a list of one or more terminal identifiers in the paging message received by PO (e.g., RRC parameter "pagingRecordList") and the terminal identifier assigned to terminal 10. For example, terminal 10 may initiate the procedure to establish a connection with the network side if the terminal identifier assigned to terminal 10 is included in the list. Here, the terminal identifier is the identifier of terminal 10, and may be, for example, a 5G-S-TMSI or may be determined based on the 5G-S-TMSI.

[0050] According to Equation 1 above, multiple terminals 10 may be assigned to the same PO. On the other hand, even if a terminal 10 receives a paging DCI, it cannot determine which terminal 10 the paging is intended for without decoding the list of terminal identifiers in the paging message. Therefore, each terminal 10 needs to perform a process to determine whether or not paging will be performed for that terminal 10. As a result, terminals 10 that are not subject to paging may consume power unnecessarily.

[0051] (PEI) Currently, 3GPP is considering a method to reduce wasted power consumption by terminals 10 that are not subject to paging. This method involves notifying terminals 10 of Paging Information (PEI) related to paging in one or more POs (Points of Operation) and controlling terminal operations in the PO based on this PEI information. For example, it is being considered to divide a group of multiple terminals 10 using the same PO into multiple subgroups and include information about the subgroups subject to paging in the PO (hereinafter referred to as "subgroup information") in the PEI information.

[0052] The subgrouping of each terminal 10 may be performed based on the terminal identifier described above, or it may be performed on a network basis. PEI information may be referred to as "PEI".

[0053] In the case of terminal identifier-based determination, terminal 10 may determine the subgroup assigned to it based on the terminal identifier or UE_ID. Specifically, terminal 10 may determine the identifier of the subgroup (hereinafter referred to as "subgroup ID") based on, in addition to the terminal identifier, at least one of the following: the number of PFs N within the DRX period T, the number of POs Ns per PF, and the total number of subgroups Nsg.

[0054] On the other hand, in the case of a network-based system, the base station 20 or core network 30 may determine which subgroup to assign to terminal 10 based on information managed on the network side (for example, the mobility status of terminal 10, paging probability, and / or the power consumption profile of terminal 10, attributes of terminal 10 regarding movement amount, etc.). The base station 20 or core network 30 may notify terminal 10 of information indicating the determined subgroup (for example, subgroup ID) via a NAS (Network Access Stratum) message or RRC message, etc.

[0055] Subgroup information may be, for example, information indicating whether or not paging is performed for each subgroup (i.e., whether paging is performed per subgroup or per group) (e.g., a 1-bit value). Alternatively, subgroup information may be information indicating which subgroups are subject to paging in one or more POs (hereinafter referred to as "paging sub-group indication information"). One or more POs may be contained within a single PF, or they may be contained within multiple PFs. For example, a PEI may correspond to up to four POs within one PF.

[0056] For example, the paging subgroup instruction information may divide the terminals 10 that share each PO into a predetermined number of subgroups (for example, up to 8 subgroups) and indicate whether each subgroup is subject to paging at each PO (whether or not there is a paging message for each subgroup). The paging subgroup instruction information may be, for example, a bitmap with a number of bits corresponding to the number of subgroups of one or more POs, or it may be information indicating the identifier of the subgroup subject to paging at each PO.

[0057] PEI information may be included in the DCI transmitted via PDCCH. A DCI containing PEI information is also called a "PEI DCI," "first downlink control information," etc. In addition to PEI information, the PEI DCI may also include information about short messages.

[0058] Terminal 10 may determine the time position of a PDCCH monitoring opportunity for PEI DCI (hereinafter referred to as "PEI-O") based on a PO (hereinafter referred to as "Target PO") that indicates which subgroup is subject to paging by the PEI DCI detected in the PEI-O. For example, the time position of the PEI-O may be determined based on a time offset (e.g., a frame-level time offset) relative to the PF containing the Target PO. Alternatively, the time position of the PEI-O may be determined based on an SSB or SS burst preceding the Target PO. Such SS burst may be, for example, the L (e.g., L=1, 2, or 3)th SS burst preceding the first PDCCH monitoring opportunity before the PO. Alternatively, the time position of the PEI-O may be determined based on a time offset relative to the Target PO.

[0059] Figure 3 shows an example of the relationship between PEI-O and PO according to this embodiment. As shown in Figure 3, PEI-O may be provided with a search space set (hereinafter referred to as "PEI search space") used for monitoring PEI DCI. PEI DCI detected by monitoring the PEI search space may correspond to one or more POs (for example, up to 4 POs per PF). One PEI DCI may correspond to multiple POs spanning multiple PFs, or to one or more POs within a single PF. Furthermore, multiple PEI DCIs may correspond to one PO.

[0060] For example, in Figure 3, the start timing of the PF including PO#0 and #1 is used as the reference time, and the start timing of the PEI-O is determined using a time offset relative to this reference time (for example, a time offset of the RF level).

[0061] In Figure 3, terminal 10, which is idle or inactive, detects the PEI DCI by monitoring the PEI search space. Based on the subgroup information within the PEI DCI, terminal 10 skips monitoring the paging search space in PO#0. On the other hand, based on the subgroup information within the PEI DCI, terminal 10 monitors the paging DCI in the paging search space in PO#1.

[0062] As described above, terminal 10, upon receiving PEI information, can skip monitoring of paging DCI at PO based on the subgroup specified in the PEI information, thereby reducing the power consumption of terminal 10. On the other hand, base station 20 transmits PEI information at PEI-O before PO, in addition to conventional paging, which increases the consumption of radio resources. Furthermore, paging is performed on the entire cell included in the TAI list or RNA where terminal 10 is located, and if PEI information is transmitted to the entire cell each time paging is performed, the consumption of radio resources will increase even further. Therefore, in order to solve these problems, it is desirable to appropriately control the transmission and reception of PEI information, taking into account the balance between reducing the power consumption of terminal 10 and increasing the consumption of radio resources.

[0063] Therefore, in this embodiment, information regarding the cell from which PEI information is transmitted (hereinafter referred to as "PEI transmission area information") is shared among the terminal 10, the base station 20, and the core network 30, and the terminal 10 and the base station 20 transmit and receive PEI information according to this information.

[0064] (Paging for idle devices) Figure 4 is a sequence diagram showing an example of a processing procedure for an idle terminal 10. In Figure 4, the RRC state of terminal 10 is assumed to be connected. The core network 30 in Figure 4 may be, for example, an AMF, but is not limited to this.

[0065] In step S100, the base station 20 sends an RRC message containing PEI transmission area information to the terminal 10. Here, the base station 20 may select one of the transmission area patterns 1 to 3 shown below to define the range of the PEI information transmission area (hereinafter referred to as the "PEI transmission area"), and send information indicating the selected transmission area pattern as the PEI transmission area information. • Transmission Area Pattern 1: Transmit PEI information in the cell where the RRC connection has been released (hereinafter referred to as the "Last Cell"). The Last Cell may also be called the cell in which terminal 10 transitioned from a connected state to an idle or inactive state, or the cell in which the RRC release message was received. • Transmission Area Pattern 2: Transmits PEI information in cells included in the cell list. The cell list is set with the identifiers of one or more cells. The cell list is expected to include the last cell, but is not necessarily limited to that. For example, if the wireless resources of the last cell are strained, a cell list that does not include the last cell may be generated. • Transmission Area Pattern 3: Sends PEI information in cells included in the TAI list. Note that Transmission Area Pattern 3 applies to idle states and not to inactive states.

[0066] The RRC message sent in step S100 may be an RRC message specific to each terminal 10. An RRC message specific to each terminal 10 may be, for example, an RRC setup message, an RRC reconfiguration message, an RRC resume message, or an RRC reestablishment message.

[0067] In step S101, the base station 20 sends an RRC release message to the terminal 10 to transition it to the idle state. Note that the processing procedures in steps S100 and S101 may be performed simultaneously. That is, the base station 20 may send an RRC release message to the terminal 10 that includes PEI transmission area information.

[0068] In step S102, after disconnecting the RRC connection in the processing procedure of step S101, the base station 20 sends a release request message to the core network 30 requesting the release of the connection associated with the terminal 10 (e.g., UE-associated logical NG-connection). This release request message may be, for example, a UE CONTEXT RELEASE REQUEST. Here, the base station 20 may also send PEI transmission area information (third information) with the same content as the PEI information sent to the terminal 10 in this release request message. The PEI transmission area information included in this release request message only needs to mean the same content as the transmission area patterns 1 to 3 described above, and does not need to be in the same format as the PEI transmission area information sent in the RRC message.

[0069] In step S103, terminal 10, upon receiving the RRC release message, transitions from the connected state to the idle state and begins monitoring the PEI-O and / or PO. If the cell in which terminal 10 is located is included in the cell indicated by the PEI transmission area information, terminal 10 monitors the PEI DCI (first downlink control information) in the PEI search space (first search space set) of the PEI-O. If PEI DCI is detected, terminal 10 controls whether to monitor or skip the paging DCI (second downlink control information) in the PO's paging search space (second search space set) based on the subgroup information within the PEI DCI. Terminal 10 recognizes which PO corresponds to which subgroup based on the subgroup information, monitors in the paging search space of the PO corresponding to the subgroup to which terminal 10 is assigned, and skips monitoring for POs that do not correspond to the subgroup to which terminal 10 is assigned.

[0070] Furthermore, if the cell where terminal 10 is located is not included in the cells indicated by the PEI transmission area information, terminal 10 will not monitor the PEI DCI in the PEI search space of PEI-O, but will instead monitor the paging DCI in the paging search space of PO.

[0071] For example, if transmission area pattern 1 is specified in the PEI transmission area information, terminal 10 will monitor PEI-O and PO while it is in the cell where the RRC connection was released, after the RRC connection is released and it transitions to an idle state. On the other hand, if it is in a different cell than the one where the RRC connection was released due to cell reselection, terminal 10 will monitor PO without monitoring PEI-O. Furthermore, if terminal 10 is again in the cell where the RRC connection was released due to cell reselection (returns to that cell), it may be configured to resume monitoring PEI-O and PO monitoring / skipping in that cell.

[0072] For example, if transmission area pattern 2 is specified in the PEI transmission area information, terminal 10 will monitor PEI-O and PO while it is located in one or more cells included in the cell list after the RRC connection is released and it transitions to an idle state. On the other hand, if it is located in a cell different from one or more cells included in the cell list due to cell reselection, terminal 10 will monitor PO without monitoring PEI-O. Furthermore, if terminal 10 is located in a cell included in the cell list again (returns) due to cell reselection, it may be configured to resume monitoring PEI-O and PO monitoring / skipping in that cell.

[0073] For example, if transmission area pattern 3 is specified in the PEI transmission area information, terminal 10 will monitor PEI-O and PO while it is located in a cell included in one or more TAs in the TAI list set for terminal 10, after the RRC connection is released and it transitions to an idle state. On the other hand, if it is located in a cell different from one or more TAs in the TAI list due to cell reselection, terminal 10 will monitor PO without monitoring PEI-O. Furthermore, if terminal 10 is located in a cell included in one or more TAs in the TAI list again (returns) due to cell reselection, it may be configured to resume monitoring PEI-O and PO monitoring / skipping in that cell.

[0074] If PEI transmission area information is not set, terminal 10 will monitor POs instead of PEI-Os. Also, even if PEI transmission area information is set, terminal 10 may skip monitoring each PO that exists between the start of the next PEI-O if PEI DCI is not detected after monitoring PEI-Os. Also, even if PEI transmission area information is set, terminal 10 may monitor each PO that exists between the start of the next PEI-O if PEI-O monitoring was not performed for any reason (for example, changing the receiving frequency to perform cell reselection).

[0075] In step S110, when paging is triggered, for example, when data to be sent to terminal 10 is generated, the core network 30 sends a paging message containing PEI transmission area information (fourth information) to the base station 20 of the cell corresponding to the registration area of ​​terminal 10 (i.e., the TAI list set on terminal 10). The core network 30 may also send paging messages that do not contain PEI transmission area information (fourth information) to base stations 20 that do not transmit PEI information (i.e., base stations 20 that do not correspond to cells in the PEI transmission area).

[0076] Furthermore, if the core network 30 assigns a subgroup to terminal 10, the paging message may include information indicating the subgroup assigned to terminal 10, in addition to the PEI transmission area information.

[0077] In step S111, the base station 20 decides whether or not to transmit PEI information when performing paging, based on the PEI transmission area information included in the paging message.

[0078] In step S112, when base station 20 transmits a paging message to terminal 10 in a cell specified by the PEI transmission area information, it transmits a PEI DCI containing subgroup information indicating the subgroup of terminal 10 in the PEI search space (first search space set) of PEI-O. Furthermore, base station 20 transmits a paging DCI in the paging search space of the PO corresponding to the subgroup, and transmits a paging message containing the terminal identifier of terminal 10 via the PDSCH scheduled by the paging DCI. On the other hand, when base station 20 transmits a paging message to terminal 10 in a cell not specified by the PEI transmission area information, it performs paging without transmitting PEI information. That is, base station 20 transmits a paging DCI in the paging search space of the PO, and transmits a paging message containing the terminal identifier of terminal 10 via the PDSCH scheduled by the paging DCI.

[0079] In step S100 of the processing procedure described above, the PEI transmission area information may be transmitted as system information. In this case, since it is not possible to set the PEI transmission area information for each terminal 10, the PEI transmission area information may, for example, be information indicating either that a cell to which PEI information is transmitted or that a cell to which PEI information is not transmitted. Alternatively, the PEI transmission area information may be information indicating either that a cell to which PEI information is transmitted or that a cell to which PEI information is not transmitted for each subgroup.

[0080] Furthermore, in the processing procedure described above, if the core network 30 requests the disconnection of the RRC connection, the core network 30 may send a release request message requesting the release of the connection associated with the terminal 10 (e.g., UE-associated logical NG-connection). This release request message may be, for example, UE CONTEXT RELEASE COMMAND. Upon receiving this release request message, the base station 20 may execute the processing procedure of step S100. Alternatively, in the processing procedure of step S102, the base station 20 may send a release completion message indicating that the release of the connection has been completed, instead of the release request message. This release request message may be, for example, UE CONTEXT RELEASE COMPLETE. Here, the base station 20 may include PEI transmission area information (third information) in the release completion message. The PEI transmission area information included in the release completion message only needs to have the same meaning as parameters 1 to 3 above, and does not need to be in the same format as the PEI transmission area information sent in the RRC message.

[0081] Furthermore, in the processing procedure described above, the names of the release request message in step S102 and the paging message in step S110 are merely examples and are not limited to these. The release request message and the paging message may also be called the first message and the second message, respectively.

[0082] (Supplementary information regarding the notification method for PEI transmission areas) If the PEI transmission area is transmission area pattern 1, the base station 20 may, in the processing procedure of step S102, transmit the cell identifier of the last cell (e.g., CellIdentity) as PEI transmission area information to the core network 30. The core network 30 may, in the processing procedure of step S110, transmit a paging message to the base station 20 of the last cell that includes the cell identifier of the last cell as PEI transmission area information. The core network 30 may also transmit paging messages to base stations 20 other than the last cell that do not include PEI transmission area information. Furthermore, if the core network 30 assigns a subgroup to the terminal 10, the core network 30 may transmit paging messages to base stations 20 other than the last cell that do not include PEI transmission area information or information indicating the subgroup assigned to the terminal 10.

[0083] If the PEI transmission area is transmission area pattern 2, the base station 20 may, in the processing procedure of step S102, send a cell list containing the identifiers of one or more cells that transmit PEI information to the core network 30 as PEI transmission area information. The core network 30 may also, in the processing procedure of step S110, send a paging message to the base stations 20 of the cells in the cell list that contains the cell list (or a cell list extracted from the cell list that contains only the cells covered by the base station 20) as PEI transmission area information. The core network 30 may also send a paging message to base stations 20 other than the cells in the cell list that does not contain PEI transmission area information. Furthermore, if the core network 30 assigns a subgroup to the terminal 10, the core network 30 may send a paging message to base stations 20 other than the cells in the cell list that does not contain PEI transmission area information or information indicating the subgroup assigned to the terminal 10.

[0084] If the PEI transmission area is transmission area pattern 3, the base station 20 may, in the processing procedure of step S102, send the TAI list to the core network 30 as PEI transmission area information. However, when the core network 30 determines the PEI transmission area, the core network 30 is aware of the TAI list set in the terminal 10, so the base station 20 does not need to send the TAI list to the core network 30. Therefore, when the core network 30 determines the PEI transmission area, the base station 20 may send a release request message to the core network 30 that does not include PEI transmission area information. Alternatively, the core network 30 may, in the processing procedure of step S110, send a paging message to the base station 20 of the cell in the TAI list that includes the TAI list (or a TAI list extracted from the cells in the TAI list that are covered by the base station 20) as PEI transmission area information.

[0085] (Paging for inactive devices) Figure 5 is a sequence diagram showing an example of a processing procedure for an inactive terminal 10. In Figure 5, the RRC state of terminal 10 is assumed to be inactive. Also, in Figure 5, base station 20-1 is the base station 20 of the cell where terminal 10 was last located, and may be called the serving base station 20. Base station 20-2 is the base station 20 of another cell included in the RNA corresponding to the cell where terminal 10 was last located, and may be called the neighbor base station 20.

[0086] In step S200, base station 20-1 sends an RRC message containing PEI transmission area information to terminal 10. Here, base station 20-1 may select one of the transmission area patterns 1 and 2 described above and transmission area pattern 4 shown below as the PEI transmission area, and send information indicating the selected transmission area pattern as the PEI transmission area information. • Transmission Area Pattern 4: Transmits PEI information using cells contained within the RNA. Note that Transmission Area Pattern 4 is applied to the inactive state but not to the idle state.

[0087] The RRC message sent in step S200 may be an RRC message specific to each terminal 10. An RRC message specific to each terminal 10 may be, for example, an RRC setup message, an RRC reconfiguration message, an RRC resume message, or an RRC reestablishment message.

[0088] In step S201, base station 20-1 sends an RRC release message to terminal 10 to transition it to an inactive state. The RRC release message includes parameters (e.g., SuspendConfig) that indicate configuration information related to the inactive state. Note that the processing procedures in steps S200 and S201 may be performed simultaneously. That is, base station 20-1 may send an RRC release message to terminal 10 that includes PEI transmission area information.

[0089] In step S202, terminal 10, upon receiving the RRC release message, transitions from the connected state to the inactive state and begins monitoring PEI-O and / or PO. For example, if transmission area pattern 4 is specified in the PEI transmission area information, terminal 10, after the RRC connection is released and it transitions to the inactive state, will monitor PEI-O and PO while it is located in one or more cells within the RNA configured for terminal 10. On the other hand, if it is located in a cell different from the cells included in the RNA due to cell reselection, terminal 10 will monitor PO instead of PEI-O. Furthermore, if terminal 10 is located in a cell included in the RNA again (returns) due to cell reselection, it may be configured to resume PEI-O monitoring and PO monitoring / skip in that cell. Other points not mentioned are the same as the processing procedure in step S103 of Figure 4, except for the processing when transmission area pattern 3 is specified.

[0090] In step S203, when paging is triggered, for example, when data to be sent to terminal 10 arrives from the core network 30, base station 20-1 decides whether or not to send PEI information when performing paging, based on the PEI transmission area information set for terminal 10 in the processing procedure of step S200.

[0091] In step S204, if base station 20-1 has set PEI transmission area information for terminal 10 in the processing procedure of step S200, it transmits a PEI DCI containing subgroup information indicating the subgroup of terminal 10 in the PEI search space (first search space set) of PEI-O. Furthermore, base station 20-1 transmits a paging DCI in the paging search space of PO corresponding to the subgroup, and also transmits a paging message containing the terminal identifier of terminal 10 via the PDSCH scheduled by the paging DCI. On the other hand, if base station 20-1 has not set PEI transmission area information for terminal 10 in the processing procedure of step S200, it performs paging without transmitting PEI information. That is, base station 20-1 transmits a paging DCI in the paging search space of PO, and also transmits a paging message containing the terminal identifier of terminal 10 via the PDSCH scheduled by the paging DCI.

[0092] In step S210, if, for example, there is no response from terminal 10 in the processing procedure of step S204, base station 20-1 sends a paging message (third message) containing PEI transmission area information (fifth information) to another base station 20-2 in RNA to cause paging. If the core network 30 assigns a subgroup to terminal 10, base station 20-1 may include information indicating the subgroup to be assigned to terminal 10 in addition to the PEI transmission area information in the paging message. Here, the PEI transmission area information included in the paging message only needs to mean the same thing as parameters 1, 2, or 4 above, and does not need to be in the same format as the PEI transmission area information sent in the RRC message in step S200.

[0093] In step S211, base station 20-2 decides whether or not to transmit PEI information when performing paging, based on the PEI transmission area information received in the processing procedure of step S210.

[0094] In step S212, when base station 20-2 sends a paging message to terminal 10 in a cell specified by the received PEI transmission area information, it sends a PEI DCI containing subgroup information indicating the subgroup of terminal 10 in the PEI search space (first search space set) of PEI-O. After sending the PEI DCI, base station 20 also sends a paging DCI in the paging search space of PO corresponding to the subgroup, and sends a paging message containing the terminal identifier of terminal 10 via the PDSCH scheduled by the paging DCI. On the other hand, when base station 20 sends a paging message to terminal 10 in a cell not specified by the PEI transmission area information, it performs paging without sending PEI information. In other words, base station 20 sends a paging DCI in the paging search space of PO, and sends a paging message containing the terminal identifier of terminal 10 via the PDSCH scheduled by the paging DCI.

[0095] In the processing procedure described above, the names of the paging messages in step S210 are merely examples and are not limited to these. The paging messages may also be called third messages.

[0096] (Supplementary information regarding the notification method for PEI transmission areas) If the PEI transmission area is transmission area pattern 1, then only base station 20-1 transmits PEI information within the RNA. Therefore, base station 20-1 may, in the processing procedure of step S210, send a paging message to base station 20-2 that does not include PEI transmission area information. Also, if the core network 30 assigns a subgroup to terminal 10, base station 20-1 may, in the processing procedure of step S210, send a paging message to base station 20-2 that does not include PEI transmission area information or information indicating the subgroup assigned to terminal 10. Furthermore, base station 20-2 may, in the processing procedure of step S212, perform paging without transmitting PEI information.

[0097] If the PEI transmission area is transmission area pattern 2, base station 20-1 may, in the processing procedure of step S210, send to base station 20-2 a cell list containing identifiers of one or more cells that transmit PEI information (or a cell list extracted from the cell list containing only the cells covered by base station 20-2) as PEI transmission area information. Base station 20-1 may also send a paging message to base station 20-2 of a cell not included in the cell list that does not contain PEI transmission area information. Furthermore, if the core network 30 assigns a subgroup to terminal 10, base station 20-1 may, in the processing procedure of step S210, send a paging message to base station 20-2 of a cell not included in the cell list that does not contain PEI transmission area information and information indicating the subgroup assigned to terminal 10.

[0098] If the PEI transmission area is transmission area pattern 4, base station 20-1 may, in the processing procedure of step S210, send to base station 20-2 a list indicating cells in RNA (or a list extracted from the cells in RNA that are covered by base station 20-2) as PEI transmission area information.

[0099] (Method for determining the PEI transmission area) The PEI transmission area may be determined by the base station 20 or the core network 30 based on the attributes of the terminal 10. The attributes of the terminal 10 may be, for example, the amount of movement of the terminal 10. For terminals 10 with low movement, transmission area pattern 1 or transmission area pattern 2 may be applied, and for terminals 10 with high movement, transmission area pattern 3 or transmission area pattern 4 may be applied. The amount of movement of the terminal 10 may be determined based on information about the amount of movement of the terminal 10, for example, set in the system information. For example, if the terminal 10 meets the stationary mobility evaluation criteria, the low mobility evaluation criteria, or the cell edge evaluation criteria, the amount of movement of the terminal 10 may be determined to be low, and if it does not meet these criteria, the amount of movement of the terminal 10 may be determined to be high. The terminal 10 may notify the base station 20 and / or the core network 30 of information indicating whether or not it meets these criteria.

[0100] Furthermore, the amount of movement of terminal 10 may be determined by the base station 20 or the core network 30 based on information indicating the movement history of terminal 10 (e.g., UE History Information) reported by terminal 10. For example, if the number of cells included in the information is below a predetermined threshold, the amount of movement of terminal 10 may be determined to be small, and if the number of cells included in the information exceeds a predetermined threshold, the amount of movement of terminal 10 may be determined to be large.

[0101] Furthermore, when the core network 30 assigns a subgroup to a terminal 10, the core network 30 may determine the PEI transmission area based on the subgroup assigned to the terminal 10. That is, the PEI transmission area may be associated with a subgroup. For example, the core network 30 may assign terminals 10 with low travel distances to subgroup 1 and transmission area pattern 1 or 2, and terminals 10 with high travel distances to subgroup 2 and transmission area pattern 3 or 4.

[0102] (modified version) When terminal 10 transitions from a connected state to an idle state, if no PEI transmission area information is set, it may be assumed that PEI information is transmitted in a cell within the TAI list set on terminal 10. In other words, terminal 10 may monitor PEI-O assuming that PEI information is transmitted according to the above transmission area pattern 3.

[0103] Furthermore, when terminal 10 transitions from a connected state to an idle state, if PEI transmission area information is not set, it may be assumed that PEI information is transmitted at the last cell. In other words, terminal 10 may perform PEI-O monitoring assuming that PEI information is transmitted according to the above transmission area pattern 1.

[0104] Furthermore, when terminal 10 transitions from a connected state to an inactive state, if no PEI transmission area information is set, it may be assumed that PEI information is transmitted in the cells within the RNA set in terminal 10. In other words, terminal 10 may perform PEI-O monitoring assuming that PEI information is transmitted according to the above transmission area pattern 4.

[0105] Furthermore, when terminal 10 transitions from a connected state to an inactive state, if PEI transmission area information is not set, it may be assumed that PEI information is transmitted at the last cell. In other words, terminal 10 may monitor PEI-O as if PEI information is transmitted according to the transmission area pattern 1 described above. When terminal 10, which has transitioned to an idle or inactive state with PEI transmission area information set, transitions back to a connected state, and the cell it is located in is included in the cell indicated by the PEI transmission area information (second information), terminal 10 may monitor paging DCI at PO instead of monitoring PEI DCI at PEI-O. That is, even if PEI transmission area information is set, terminal 10 in a connected state may monitor paging DCI at PO to receive short messages instead of monitoring PEI-O. This makes it possible to suppress the increase in power consumption caused by terminal 10 in a connected state unnecessarily monitoring PEI-O.

[0106] According to the processing procedure described above, terminal 10 will monitor PEI-O within the set PEI transmission area and will not monitor PEI-O outside the set PEI transmission area. This allows terminal 10 to recognize the cells to which PEI information is transmitted and to appropriately control the monitoring of PEI information. Furthermore, base station 20 or core network 30 can set the PEI transmission area according to the attributes of terminal 10. For example, for terminal 10 with low movement (i.e., terminal 10 that is expected to stay in the last cell most of the time), it is possible to transmit PEI information only to the last cell, thereby reducing the power consumption of terminal 10 and suppressing the increase in wireless resources. Also, for terminal 10 with high movement (i.e., terminal 10 that is expected to stay in the last cell less often), it is possible to reduce the number of times terminal 10 monitors PO by transmitting PEI information in the TAI list or cells within RNA, thereby reducing the power consumption of terminal 10.

[0107] (Example of specification change) Figure 6 shows an example of a specification change (part 1) in the 3GPP specification (TS38.304). Note that the following example of a specification change is just one example, and is not limited to those described below.

[0108] As shown in Figure 6, PEI information may be transmitted in any of the following locations: (1) a cell in which terminal 10 transitions to an idle or inactive state triggered by the reception of an RRC release message containing the parameter (lastCell) (corresponding to transmission area pattern 1 described above); (2) a cell in the RNA relating to terminal 10 that transitions to an inactive state triggered by the reception of an RRC release message containing the parameter (sameAsRNA) (corresponding to transmission area pattern 4 described above); or (3) a cell in the TAI list relating to terminal 10 that transitions to an idle state triggered by the reception of an RRC release message containing the parameter (sameAsTA-List) (corresponding to transmission area pattern 3 described above).

[0109] Furthermore, if monitoring via PEI-O is not possible (or not performed) due to, for example, cell re-selection, terminal 10 will monitor all POs until the next PEI-O begins. Also, if terminal 10 moves to a cell where PEI information is not transmitted due to, for example, cell re-selection, terminal 10 will monitor all POs until it returns to a cell where PEI is transmitted.

[0110] Figure 7 shows an example of a specification change (part 1) in the 3GPP specification (TS38.331). The underlined portion of Figure 7 represents the specification change example according to this embodiment. Note that the following specification change example is just one example, and is not limited to those described below.

[0111] As shown in Figure 7, the RRC release message includes PEI transmission area information (e.g., "pei-TransmissionArea-r17") and may specify one of three parameters (lastCell, SameAsRNA, SameAsTA-List).

[0112] Figure 8 shows an example (part 2) of the specification changes to the 3GPP specification (TS38.304) relating to the paging process according to this embodiment. As shown in Figure 8, PEI information may be transmitted in any of the following ways: (1) a cell in the list set in the RRC release message (corresponding to the transmission area pattern 2 described above), (2) a cell in the RNA relating to terminal 10 that has transitioned to an inactive state triggered by the reception of an RRC release message containing the parameter (sameAsRNA) (corresponding to the transmission area pattern 4 described above), or (3) a cell in the TAI list relating to terminal 10 that has transitioned to an idle state triggered by the reception of an RRC release message containing the parameter (sameAsTA-List) (corresponding to the transmission area pattern 3 described above). Other points not mentioned may be the same as in Figure 6.

[0113] Figure 9 shows an example of specification changes (part 2) of the 3GPP specification (TS38.331). The underlined portion of Figure 9 is an example of specification changes according to this embodiment. As shown in Figure 9, the RRC release message includes PEI transmission area information (e.g., "pei-TransmissionArea-r17"), and one of three types of parameters (pei-Cell-r17, SameAsRNA, SameAsTA-List) may be specified. In addition, pei-Cell-r17 may include multiple cell IDs (CellIdentity).

[0114] Figures 10 and 11 show examples of specification changes in the 3GPP specification (TS38.413). As shown in the upper part of the underlined section in Figures 10 and 11, when the AMF receives a UE CONTEXT RELEASE COMPLETE message containing an information element (Last Cell Information), it stores the information element (Last Cell Information) and uses it for subsequent PEI transmission. This example of specification change corresponds to the processing procedure in step S102 of Figure 4, when PEI transmission area information corresponding to transmission area pattern 1 is transmitted from the base station 20 to the core network 30.

[0115] Furthermore, as shown in the lower part of the underlined sections in Figures 10 and 11, when the AMF receives a UE CONTEXT RELEASE COMPLETE message containing information elements (List of Cells Information), it stores the information elements (List of Cells Information) and uses them for subsequent PEI transmission. This example of specification change corresponds to the processing procedure in step S102 of Figure 4, where PEI transmission area information corresponding to transmission area pattern 2 is transmitted from the base station 20 to the core network 30.

[0116] In addition, in the example of specification changes shown in Figure 11, instead of adding a new information element (Last Cell Information or List of Cells Information), the information element according to this embodiment (Last Cell Information or List of Cells Information) may be included in the existing information element (Information on Recommended Cells and RAN Nodes for Paging).

[0117] Figures 12 and 13 show examples of specification changes in the 3GPP specification (TS38.413). As shown in the upper part of the underlined section in Figures 12 and 13, when base station 20 (NG-RAN) receives a paging message containing an information element (Last Cell Information), base station 20 transmits PEI information only in the cell indicated by the information element (Last Cell Information). This example of specification change corresponds, for example, to the processing procedure in step S110 of Figure 4, where PEI transmission area information corresponding to transmission area pattern 1 is transmitted from the core network 30 to base station 20, and base station 20 transmits PEI information in the cell specified by the received PEI transmission area information.

[0118] Furthermore, as shown in the lower part of the underlined sections in Figures 12 and 13, when the base station 20 (NG-RAN) receives a paging message containing an information element (List of Cells Information), the base station 20 transmits PEI information only in the cells indicated by the information element (List of Cells Information). This example of specification change corresponds, for example, to the processing procedure in step S110 of Figure 4, where PEI transmission area information corresponding to transmission area pattern 2 is transmitted from the core network 30 to the base station 20, and the base station 20 transmits PEI information in the cells specified by the received PEI transmission area information.

[0119] In addition, in the example of specification changes shown in Figure 13, instead of adding a new information element (Last Cell Information or List of Cells Information), the information element according to this embodiment (Last Cell Information or List of Cells Information) may be included in the existing information element (Assistance Data for RAN Pagin).

[0120] Figure 14 shows an example of a specification change in the 3GPP specification (TS38.423). As shown in the underlined section of Figure 14, when base station 20 (NG-RAN) receives a paging message containing an information element (Last Cell Information), it transmits PEI information only in the cell indicated by the information element (Last Cell Information).

[0121] Figure 15 shows an example of a specification change in the 3GPP specification (TS38.423). As shown in the underlined part of Figure 15, when base station 20 (NG-RAN) receives a paging message containing an information element (List of Cells Information), it transmits PEI information only in the cells indicated by the information element (List of Cells Information). This example of a specification change corresponds, for example, to the processing procedure in step S210 of Figure 5, where PEI transmission area information corresponding to transmission area pattern 2 is transmitted from base station 20-1 to base station 20-2, and base station 20-2 transmits PEI information in the cells specified by the received PEI transmission area information.

[0122] (Configuration of the wireless communication system) Next, the configuration of each device in the wireless communication system 1 described above will be explained. Note that the following configuration is for illustrating the necessary configurations in this embodiment and does not preclude each device from having functional blocks other than those shown.

[0123] <Hardware Configuration> Figure 16 shows an example of the hardware configuration of each device in the wireless communication system according to this embodiment. Each device in the wireless communication system 1 (for example, terminal 10, base station 20, core network 30, etc.) includes a processor 11, a storage device 12, a communication device 13 that performs wired or wireless communication, an input device that accepts various input operations, and an input / output device 14 that outputs various information.

[0124] The processor 11 is, for example, a CPU (Central Processing Unit) and controls each device in the wireless communication system 1. The processor 11 may perform various processes described in this embodiment by reading and executing a program from the storage device 12. Each device in the wireless communication system 1 may be composed of one or more processors 11. Each of these devices may also be called a computer.

[0125] The storage device 12 consists of, for example, memory, an HDD (Hard Disk Drive), and / or an SSD (Solid State Drive). The storage device 12 may store various information necessary for the execution of processing by the processor 11 (for example, programs executed by the processor 11).

[0126] The communication device 13 is a device that communicates via a wired and / or wireless network, and may include, for example, a network card, a communication module, a chip, an antenna, etc. The communication device 13 may also include an amplifier, an RF (Radio Frequency) device that processes wireless signals, and a BB (BaseBand) device that processes baseband signals.

[0127] For example, an RF device generates a radio signal to be transmitted from an antenna by performing D / A conversion, modulation, frequency conversion, power amplification, etc., on a digital baseband signal received from a BB device. The RF device also generates a digital baseband signal by performing frequency conversion, demodulation, A / D conversion, etc., on a radio signal received from an antenna and transmits it to the BB device.

[0128] The BB device performs the process of converting data into a digital baseband signal. Specifically, the BB device may map the data to subcarriers, perform an IFFT to generate OFDM symbols, insert CPs into the generated OFDM symbols, and generate a digital baseband signal. The BB device may also apply a transform precoder (DFT spread) before mapping the data to subcarriers.

[0129] Furthermore, the BB device performs a process to convert the digital baseband signal into data. Specifically, the BB device may remove the CP from the digital baseband signal input from the RF device, perform an FFT on the signal from which the CP has been removed, and extract the signal in the frequency domain. Alternatively, the BB device may apply an IDFT to the signal in the frequency domain.

[0130] The input / output device 14 includes, for example, an input device such as a keyboard, touch panel, mouse, and / or microphone, and an output device such as a display and / or speaker.

[0131] The hardware configuration described above is merely an example. Each device within the wireless communication system 1 may omit some of the hardware shown in Figure 16, or may include hardware not shown in Figure 16. Furthermore, the hardware shown in Figure 16 may be comprised of one or more chips.

[0132] <Functional Block Configuration> ≪Device≫ Figure 17 shows an example of the functional configuration of a terminal according to this embodiment. As shown in Figure 17, the terminal 10 comprises a receiving unit 101, a transmitting unit 102, and a control unit 103. The functional configuration shown in Figure 17 is merely an example, and the names of the functional categories and functional units can be anything as long as they can perform the operations according to this embodiment. Also, the receiving unit 101 and the transmitting unit 102 may be collectively referred to as the communication unit.

[0133] Furthermore, all or part of the functions realized by the receiving unit 101 and the transmitting unit 102 can be realized using the communication device 13. In addition, all or part of the functions realized by the receiving unit 101 and the transmitting unit 102, and the control unit 103 can be realized by the processor 11 executing a program stored in the storage device 12. The program can be stored in a storage medium. The storage medium on which the program is stored may be a non-transitory computer-readable medium. The non-transitory storage medium is not particularly limited, but may be a USB memory or a CD-ROM, for example.

[0134] The receiving unit 101 receives signals (e.g., DL signals and / or sidelink signals). The receiving unit 101 may also receive information and / or data transmitted via such signals. Here, "receiving" may include performing reception-related processing such as receiving, demapping, demodulating, decoding, monitoring, and measuring at least one of the following: receiving, demapping, demodulating, decoding, monitoring, and measuring radio signals. The DL signals may include at least one of the following: PDSCH, PDCCH, downlink reference signal, synchronization signal, PBCH, etc.

[0135] The receiver 101 monitors PDCCH candidates in the search space and detects DCI. The receiver 101 may receive DL data via PDSCH scheduled using DCI. The DL data may include downlink user data and / or control information from higher layers (e.g., at least one parameter from the MAC layer, RRC layer, and Non Access Stratum (NAS) layer). The receiver 101 may also receive system information via PBCH and / or PDSCH.

[0136] The transmitter 102 transmits signals (e.g., UL signals and / or sidelink signals). The transmitter 102 may also transmit information and / or data transmitted via such signals. Here, "transmit" may include performing transmission-related processing such as encoding, modulation, mapping, and transmitting radio signals. The UL signals may include at least one of the following: PUSCH, PRACH, PUCCH, uplink reference signals, etc.

[0137] The transmitting unit 102 may transmit UL data via PUSCH, which is scheduled using the DCI received by the receiving unit 101. The UL data may include uplink user data and / or control information from higher layers (e.g., at least one parameter from the MAC layer, RRC layer, and NAS layer).

[0138] The control unit 103 performs various controls on the terminal 10. Specifically, the control unit 103 may control the operation of the terminal 10 based on various configuration information (for example, RRC layer parameters) received by the receiving unit 101 from the base station 20 or other terminal 10. The operation of the terminal 10 based on such information may be synonymous with "configuration information being set in the terminal 10 (configured)".

[0139] The control unit 103 may control the reception of signals in the receiving unit 101. The control unit 103 may also control the transmission of signals in the transmitting unit 102. The control unit 103 may decide whether or not to apply a transform precoder to the signal transmitted by the transmitting unit 102.

[0140] In this embodiment, terminal 10 may include a receiving unit that receives an RRC message (e.g., an RRC release message) containing second information (e.g., PEI transmission area information) about a cell to which first information (e.g., PEI information) about paging in one or more paging opportunities is transmitted, and a control unit that controls monitoring of first downlink control information (e.g., PEI DCI) containing the first information when it is idle or inactive and the cell it is located in is included in the cell indicated by the second information, and controls monitoring of second downlink control information (e.g., paging DCI) containing information about scheduling of downlink shared channels for transmitting paging messages in paging opportunities and / or information about short messages, based on the first information.

[0141] If the control unit 103 is in an idle or inactive state and the cell it is located in is not included in the cells indicated by the second information, it may monitor the second downlink control information without monitoring the first downlink control information.

[0142] The second piece of information may contain one of the following: a cell whose RRC connection has been released, a cell within the RAN notification area (RNA), or a cell within the tracking area list (TAI list).

[0143] The second piece of information may contain one of the following: the cell list set in the RRC message, a cell in the RAN notification area, or a cell in the tracking area list.

[0144] If the control unit 103 is unable to monitor the first downlink control information during the first reception opportunity (PEI-O) for monitoring the first downlink control information (i.e., does not monitor it), it may monitor the second downlink control information during the second reception opportunity (PO) for monitoring the second downlink control information until the next first reception opportunity. If the control unit 103 is in a connected state and the cell it is located in is included in the cell indicated by the second information, it may monitor the second downlink control information without monitoring the first downlink control information.

[0145] ≪Base station≫ Figure 18 shows an example of the functional block configuration of a base station according to this embodiment. As shown in Figure 18, the base station 20 includes a first receiving unit 201, a second receiving unit 202, a first transmitting unit 203, a second transmitting unit 204, and a control unit 205. The functional configuration shown in Figure 18 is merely an example, and the names of the functional categories and functional units can be anything as long as they can perform the operation according to this embodiment. Furthermore, the first receiving unit 201 and the second receiving unit 202 may be collectively referred to as the receiving unit. Furthermore, the first transmitting unit 203 and the second transmitting unit 204 may be collectively referred to as the transmitting unit. Furthermore, the first receiving unit 201, the second receiving unit 202, the first transmitting unit 203, and the second transmitting unit 204 may be collectively referred to as the communication unit.

[0146] Furthermore, all or part of the functions implemented by the first receiver 201, the second receiver 202, the first transmitter 203, and the second transmitter 204 can be implemented using the communication device 13. For example, the first receiver 201 and the first transmitter 203 may be implemented using the communication device 13 for a wireless network, and the second receiver 202 and the second transmitter 204 may be implemented using the communication device 13 for a wired network. In addition, all or part of the functions implemented by the first receiver 201, the second receiver 202, the first transmitter 203, and the second transmitter 204, and the control unit 205 can be implemented by the processor 11 executing a program stored in the storage device 12. The program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-temporary storage medium. The non-temporary storage medium is not particularly limited, but may be, for example, a USB memory or a CD-ROM.

[0147] The first receiving unit 201 receives signals (e.g., UL signals and / or sidelink signals). The first receiving unit 201 may also receive information and / or data (e.g., the UL data) transmitted via the said signals.

[0148] The second receiving unit 202 receives signals (for example, C-plane signals and U-plane signals) from other base stations 20 or the core network 30.

[0149] The first transmitting unit 203 transmits a signal (e.g., a DL signal and / or a sidelink signal). The first transmitting unit 203 may also transmit information and / or data (e.g., the DL data) transmitted via the signal.

[0150] The second transmitting unit 204 transmits signals (for example, C-plane signals and U-plane signals) to other base stations 20 or the core network 30.

[0151] The control unit 205 performs various controls for communication with the terminal 10, other base stations 20, and the core network 30. Specifically, the control unit 205 may determine information regarding various settings that will be notified to the terminal 10. Transmitting such information to the terminal 10 may be synonymous with "setting such information on the terminal."

[0152] The control unit 205 may control the reception of signals in the first receiving unit 201 and the second receiving unit 202. The control unit 205 may also control the transmission of signals in the first transmitting unit 203 and the second transmitting unit 204.

[0153] In this embodiment, the base station 20 may include a first transmitting unit 203 that transmits an RRC message to the terminal 10 instructing it to transition to an idle state, which includes a first piece of information (e.g., PEI information) about the cell (area) to which the first piece of information about paging in one or more paging opportunities is transmitted (e.g., PEI transmission area information); and a second transmitting unit 204 that, after transmitting the RRC message instructing it to transition to an idle state, transmits a message to the core network 30 that includes a third piece of information (e.g., PEI transmission area information) about the cell to which the first piece of information is transmitted.

[0154] Furthermore, the base station 20 includes a second receiving unit 202 (receiving unit) that receives a paging message from the core network that includes a fourth piece of information (e.g., PEI transmission area information) relating to the cell on which the first piece of information is transmitted, and the first transmitting unit 203, when transmitting a paging message in the cell indicated by the fourth piece of information, may, after transmitting the first piece of information, transmit downlink control information (e.g., paging DCI) that includes information regarding scheduling of downlink shared channels for transmitting paging messages in a paging opportunity and / or information regarding short messages.

[0155] The first transmitting unit 203 sends an RRC message to the terminal 10 instructing it to transition to an inactive state, which includes the second information (PEI transmission area information). The second transmitting unit 204 may, after sending an RRC message instructing it to transition to an inactive state, send a message to another base station 20 that includes the fifth information (e.g., PEI transmission area information) relating to the cell on which the first information is transmitted.

[0156] Furthermore, the control unit 205 may determine (select) second information based on the attributes of the terminal 10. The attributes of the terminal 10 may be, for example, information relating to the amount of movement of the terminal 10.

[0157] In this embodiment, the base station 20 (first base station) may include a second receiving unit 202 (receiving unit) that receives a paging message from another base station 20 (adjacent base station, second base station) that includes a fifth piece of information (e.g., PEI transmission area information) about a cell (area) to which a first piece of information (e.g., PEI information) about paging in one or more paging opportunities is transmitted, and a first transmitting unit 203 that, when transmitting a paging message in the cell indicated by the fifth piece of information, transmits downlink control information (e.g., paging DCI) after transmitting the first piece of information, which includes information about scheduling of downlink shared channels for transmitting paging messages in paging opportunities and / or information about short messages.

[0158] ≪Core Network≫ Figure 19 shows an example of the functional configuration of the core network 30 according to this embodiment. As shown in Figure 19, the core network 30 comprises a receiving unit 301, a transmitting unit 302, and a control unit 303. The functional configuration shown in Figure 19 is merely an example, and the names of the functional categories and functional units can be anything as long as they can perform the operation according to this embodiment. In addition, the receiving unit 301 and the transmitting unit 302 may be collectively referred to as the communication unit.

[0159] Furthermore, all or part of the functions realized by the receiving unit 301 and the transmitting unit 302 can be realized using the communication device 13. In addition, all or part of the functions realized by the receiving unit 301 and the transmitting unit 302, and the control unit 303 can be realized by the processor 11 executing a program stored in the storage device 12. The program can be stored in a storage medium. The storage medium on which the program is stored may be a computer-readable non-temporary storage medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM.

[0160] The receiving unit 301 receives signals (for example, NAS messages, C-plane signals, and U-plane signals) from the terminal 10, base station 20, or other core network devices.

[0161] The transmitting unit 302 transmits signals (for example, NAS messages, C-plane signals, and U-plane signals) to the terminal 10, base station 20, or other core network devices.

[0162] The control unit 303 performs various controls on the core network 30. The control unit 303 may also control the operation of the terminal 10 using information about various settings (for example, parameters of NAS messages). The control unit 303 may also control the operation of the base station 20 using messages of the NG application protocol.

[0163] The control unit 303 may control the reception of signals in the receiving unit 301. The control unit 303 may also control the transmission of signals in the transmitting unit 302.

[0164] In this embodiment, the core network 30 includes a receiving unit 301 that receives a message from a base station 20 containing a third piece of information (e.g., PEI transmission area information) relating to a cell to which a first piece of information relating to paging (e.g., PEI information) is transmitted in one or more paging opportunities, and a transmitting unit 302 that, when paging for a terminal 10 is triggered, transmits a message containing a fourth piece of information (e.g., PEI transmission area information) relating to a cell to which the first piece of information is transmitted, based on the third piece of information, to a base station 20 corresponding to the cell to which the first piece of information is transmitted among the one or more base stations 20 that perform paging, and transmits a message that does not contain the fourth piece of information to a base station 20 corresponding to the cell to which the first piece of information is not transmitted among the one or more base stations 20 that perform paging.

[0165] Furthermore, the control unit 303 may determine (select) a fourth piece of information to be set on the terminal 10 based on the attributes of the terminal 10, instead of the third piece of information. The attributes of the terminal 10 may be, for example, information relating to the amount of movement of the terminal 10. Also, when paging is triggered for the terminal 10, the transmission unit 302 may send a message containing the fourth piece of information determined (selected) based on the information relating to the amount of movement of the terminal 10 to the base station 20 corresponding to the cell to which the first piece of information is transmitted among the one or more base stations 20 that perform paging, and send a message not containing the fourth piece of information to the base station 20 corresponding to the cell to which the first piece of information is not transmitted among the one or more base stations 20 that perform paging.

[0166] (supplement) In the above embodiment, the PEI may also be called a paging subgroup indicator.

[0167] The various signals, information, and parameters in the above embodiment may be signaled at any layer. That is, the various signals, information, and parameters may be replaced by signals, information, and parameters of any layer, such as a higher layer (e.g., NAS layer, RRC layer, MAC layer, etc.) or a lower layer (e.g., physical layer). Furthermore, notification of predetermined information is not limited to explicit notification, but may also be done implicitly (e.g., by not notifying the information or by using other information).

[0168] Furthermore, the names of the various signals, information, parameters, IE, channels, time units, and frequency units in the above embodiments are merely illustrative and may be replaced with other names. For example, a slot may have any name as long as it is a time unit having a predetermined number of symbols. Similarly, an RB may have any name as long as it is a frequency unit having a predetermined number of subcarriers. Also, "first ~" and "second ~" are merely identifiers of multiple pieces of information or signals and may be rearranged as appropriate.

[0169] For example, in the present embodiment described above, examples of physical channels for transmitting DL data, UL data, DCI, broadcast information, and RA preamble are given as PDSCH, PUSCH, PDCCH, PBCH, and PRACH, respectively, but the names are not limited to these, as long as the physical channels have similar functions. Furthermore, these physical channels may be rephrased as the transport channels to which the physical channels are mapped. Furthermore, PDSCH, PUSCH, PDCCH, PBCH, and PRACH may be rephrased as transport channels mapped to physical channels (for example, Downlink Shared Channel (DL-SCH), Uplink Shared Channel (UL-SCH), Broadcast Channel (BCH), and at least one Random Access Channel (RCH)). These transport channels may also be rephrased as logical channels to which the transport channels are mapped. DL data and UL data are data for the downlink and uplink links, respectively, and this data may include user data and control information from higher layers (for example, RRC parameters, Medium Access Control (MAC) parameters, etc.).

[0170] Furthermore, the applications of terminal 10 in the above embodiment (e.g., RedCap, IoT, etc.) are not limited to those exemplified, and it may be used for any application (e.g., eMBB, URLLC, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.) as long as it has similar functionality. Also, the format of various information is not limited to the above embodiment, and may be changed as appropriate, such as bit representation (0 or 1), boolean value (true or false), integer value, character, etc. Also, singular and plural in the above embodiment may be interchangeable.

[0171] The embodiments described above are provided to facilitate understanding of this disclosure and are not intended to limit it. The flowcharts, sequences, elements, arrangements, indices, conditions, etc., described in the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, it is possible to partially replace or combine at least some of the configurations described in the embodiments above. <Note> This embodiment can be expressed as follows: <Note 1> A receiving unit that receives an RRC message containing second information about a cell to which first information about paging in one or more paging opportunities is transmitted, A control unit controls the monitoring of first downlink control information including the first information when the cell is idle or inactive and the cell in which it resides is included in the cell indicated by the second information, and controls the monitoring of second downlink control information including information regarding scheduling of downlink shared channels for transmitting paging messages in the paging opportunity and / or information regarding short messages, based on the first information. A terminal equipped with the following features. <Note 2> If the control unit is in an idle or inactive state and the cell it is located in is not included in the cell indicated by the second information, it will monitor the second downlink control information without monitoring the first downlink control information. The terminals listed in Appendix 1. <Note 3> The second piece of information contains one of the following: a cell from which the RRC connection has been released, a cell within the RAN notification area, and a cell within the tracking area list. The terminals listed in Appendix 1 or 2. <Note 4> The second information includes one of the following: the cell list set in the RRC message, the cells in the RAN notification area, and the cells in the tracking area. The terminals listed in Appendix 1 or 2. <Note 5> If the control unit is unable to monitor the first downlink control information during the first reception opportunity for monitoring the first downlink control information, it will monitor the second downlink control information during the second reception opportunity for monitoring the second downlink control information until the next first reception opportunity. A terminal specified in any one of the following appendices 1 to 4. <Note 6> The control unit, when in a connected state and the cell it is located in is included in the cell indicated by the second information, monitors the second downlink control information without monitoring the first downlink control information. A terminal specified in any one of the following appendices 1 to 5. <Note 7> A first transmitting unit that transmits an RRC message to a terminal instructing it to transition to an idle state, which includes second information about a cell to which first information about paging in one or more paging opportunities is transmitted, A second transmission unit transmits to the core network a message containing third information relating to the cell on which the first information is transmitted, after sending an RRC message instructing the transition to the idle state. A base station having <Note 8> The system includes a receiving unit that receives a paging message from the core network, which includes a fourth piece of information relating to the cell from which the first piece of information is transmitted, When the first transmitting unit transmits a paging message in the cell indicated by the fourth information, after transmitting the first information, it transmits downlink control information including information regarding scheduling of downlink shared channels for transmitting paging messages in the paging opportunity and / or information regarding short messages. The base station described in Appendix 7. <Note 9> The first transmitting unit transmits an RRC message to the terminal that includes the second information and instructs it to transition to an inactive state. After the second transmitting unit transmits an RRC message instructing to transition to the inactive state, it transmits a message to another base station containing fifth information relating to the cell on which the first information is transmitted. The base station described in Appendix 7 or 8. <Note 10> The system further includes a control unit that determines the second information based on the attributes of the terminal, A base station as described in any one of the items 7 to 9 of the appendix. <Note 11> A receiving unit that receives a paging message from another base station, which includes a fifth piece of information relating to a cell from which a first piece of information relating to paging in one or more paging opportunities is transmitted, When transmitting a paging message in the cell indicated by the fifth information, the transmitting unit transmits, after transmitting the first information, downlink control information including information regarding scheduling of the downlink shared channel for transmitting paging messages in the paging opportunity and / or information regarding short messages, A base station having <Note 12> A receiving unit that receives a message from a base station containing a message containing a third piece of information about a cell on which a first piece of information about paging in one or more paging opportunities is transmitted, When paging is triggered for a terminal, a transmitting unit transmits a message containing fourth information relating to the cell on which the first information is transmitted, based on the third information, to the base station corresponding to the cell on which the first information is transmitted among the one or more base stations performing the paging, and transmits a message not containing fourth information to the base station corresponding to the cell on which the first information is not transmitted among the one or more base stations. A core network device having <Note 13> The process of receiving an RRC message containing second information about a cell to which first information about paging in one or more paging opportunities is transmitted, If the cell is idle or inactive and the cell in which it resides is included in the cell indicated by the second information, the monitoring of the first downlink control information including the first information is controlled, and based on the first information, the monitoring of the second downlink control information including information regarding scheduling of downlink shared channels for transmitting paging messages in the paging opportunity and / or information regarding short messages is controlled. A communication method on a terminal, including [this]. <Note 14> The process involves sending an RRC message to a terminal instructing it to transition to an idle state, which includes second information relating to a cell on which first information relating to paging in one or more paging opportunities is transmitted. After sending an RRC message instructing the transition to the idle state, the process includes sending a message to the core network containing third information relating to the cell on which the first information is transmitted. A communication method at a base station, including [this]. <Note 15> The process of receiving a paging message from another base station, which includes fifth information relating to a cell on which first information relating to paging in one or more paging opportunities is transmitted, When a paging message is transmitted in the cell indicated by the fifth information, the process includes transmitting the first information, and then transmitting downlink control information including information regarding scheduling of the downlink shared channel for transmitting the paging message and / or information regarding the short message in the paging opportunity, A communication method at a base station, including [this]. <Note 16> The process includes receiving a message from a base station containing a message containing a third piece of information about a cell on which a first piece of information about paging in one or more paging opportunities is transmitted, When paging is triggered for a terminal, the process includes: sending a message containing fourth information relating to the cell on which the first information is transmitted, based on the third information, to the base station corresponding to the cell on which the first information is transmitted among one or more base stations performing the paging; and sending a message not containing fourth information to the base station corresponding to the cell on which the first information is not transmitted among one or more base stations. A communication method in a core network device, including [the specified element].

Claims

1. A cell includes a receiving unit that receives system information from a base station, The system includes, in an idle or inactive state, a control unit that, when the system information includes first information and a radio resource control (RRC) release message is received in the cell, performs monitoring of the physical downlink control channel (PDCCH) for downlink control information (DCI) including second information in the cell, The first information indicates that when the RRC release message is received in the cell, the cell will perform PDCCH monitoring for DCI including the second information, and the second information indicates a subgroup of terminals. The control unit, PDCCH monitoring of DCI including the second information is performed at one or more monitoring opportunities corresponding to paging opportunities. The aforementioned subgroup of terminals includes the subgroup of terminals in the aforementioned one or more paging opportunities. Terminal.

2. The control unit, If the first information is not set, PDCCH monitoring of DCI including the second information is performed in the cell where the cell is located. The terminal according to claim 1.

3. The subgroup of the terminals is determined based on the identifier of the terminal, or assigned by the core network device. The terminal according to claim 1 or 2.

4. The DCI including the second information is the first DCI The control unit, Based on the second information, the PDCCH is monitored for the second DCI used for scheduling the physical downlink shared channel (PDSCH) that transmits paging messages in one or more paging opportunities. If it is not possible to monitor the PDCCH for the first DCI, then the PDCCH for the second DCI will be monitored during one or more of the paging opportunities. The terminal according to claim 1.

5. The case in which monitoring of PDCCH for the first DCI is not possible includes the period during which cell reselection is performed by the terminal. The terminal according to claim 4.

6. A transmission unit in the cell that transmits system information to the terminal, The system includes a control unit that, when the terminal is idle or inactive, controls the transmission of downlink control information (DCI) including second information to the terminal via a physical downlink control channel (PDCCH) based on the transmission of a radio resource control (RRC) release message in the cell, wherein the system information includes first information, and the control unit transmits downlink control information (DCI) including second information to the terminal via a physical downlink control channel (PDCCH). The first information indicates that when the RRC release message is received in the cell, the cell will perform PDCCH monitoring for DCI including the second information, and the second information indicates a subgroup of terminals. The control unit, Control the DCI containing the second information to be transmitted to the terminal during monitoring opportunities corresponding to one or more paging opportunities. The aforementioned subgroup of terminals includes the subgroup of terminals in the aforementioned one or more paging opportunities. Base station.

7. The subgroup of the terminals is determined based on the identifier of the terminal, or assigned by the core network device. The base station according to claim 6.

8. If the terminal is unable to perform PDCCH monitoring for DCI including the second information, this includes the period during which cell reselection is performed by the terminal. The base station according to claim 6.

9. The process of receiving system information from the base station in the cell, The system includes the step of, when the system information includes first information and a radio resource control (RRC) release message is received in the cell during an idle or inactive state, monitoring the physical downlink control channel (PDCCH) for downlink control information (DCI) including second information in the cell, The first information indicates that when the RRC release message is received in the cell, the cell will perform PDCCH monitoring for DCI including the second information, and the second information indicates a subgroup of terminals. PDCCH monitoring of DCI including the second information is performed in monitoring opportunities corresponding to one or more paging opportunities. The aforementioned subgroup of terminals includes the subgroup of terminals in the aforementioned one or more paging opportunities. Communication methods on a terminal.

10. If the first information is not set, the process includes monitoring the PDCCH for DCI including the second information in the cell where the cell is located. The communication method according to claim 9.

11. The subgroup of the terminals is determined based on the identifier of the terminal, or assigned by the core network device. The communication method according to claim 9 or 10.

12. The DCI including the second information is the first DCI Based on the second information, the process involves monitoring the PDCCH for the second DCI used for scheduling the physical downlink shared channel (PDSCH) that transmits paging messages in one or more paging opportunities, If it is not possible to monitor the PDCCH for the first DCI, the process includes a step of monitoring the PDCCH for the second DCI during one or more paging opportunities. The communication method described in claim 9.

13. The period during which PDCCH monitoring for the first DCI is not possible includes the period during which cell reselection is performed by the terminal. The communication method according to claim 12.

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