Terminal, base station and wireless communication method

Abstract

Provided is a terminal comprising: a reception unit which receives system information and which receives an RRC release message; and a control unit that stores a residing cell as a last-used cell when the RRC release message is received, wherein the control unit carries out such control that a PDCCH for a paging early indication is monitored in the last-used cell on the basis of information about a cell to which the paging early indication included in PEI settings information in the system information is transmitted.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2022-018558, filed on February 9, 2022, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a terminal, a base station, and a communication method. [Background technology]

[0003] The Third Generation Partnership Project (3GPP), an international standardization organization, has specified Release 15 of New Radio (NR), a fifth generation (5G) RAT, as the successor to Long Term Evolution (LTE), a 3.9th generation radio access technology (RAT), and LTE-Advanced, a fourth generation RAT (see, for example, Non-Patent Document 1). LTE and / or LTE-Advanced are also called Evolved Universal Terrestrial Radio Access (E-UTRA). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V15.2.0 (2018-06) Summary of the Invention [Problem to be solved by the invention]

[0005] In NR, a terminal monitors downlink control information (DCI) (hereinafter referred to as "paging DCI") including information regarding the scheduling of a downlink shared channel (e.g., a physical downlink shared channel (PDSCH)) that transmits 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.

[0006] Currently, 3GPP is considering notifying a terminal of information regarding paging in one or more POs (hereinafter referred to as "Paging Early Indication (PEI) information" or "first information") and controlling terminal operation in the PO based on the PEI information.

[0007] An object of the present disclosure is to provide a terminal, a base station, and a wireless communication method that are capable of appropriately controlling the transmission and reception of PEI information.

[0008] A terminal according to one embodiment of the present disclosure includes a receiving unit that receives system information and an RRC release message, and a control unit that, when the RRC release message is received, stores the serving cell as a last used cell, and the control unit controls the last used cell to monitor a PDCCH for the paging pre-indication based on information regarding the cell to which the paging pre-indication is transmitted, which is included in PEI setting information in the system information.

[0009] According to the present disclosure, it is possible to appropriately control the transmission and reception of PEI information. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of an overview of a wireless communication system according to this embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a PO according to this embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the relationship between the PEI-O and the PO according to this embodiment. [Figure 4] FIG. 4 is a diagram showing a method for transmitting PEI transmission area information using system information. [Figure 5] FIG. 5 is a sequence diagram showing an example of a processing procedure performed by the terminal 10 and the base station 20. As shown in FIG. [Figure 6] FIG. 6 is a diagram showing an example (part 1) of specification changes to the 3GPP specification (TS38.304). [Figure 7] FIG. 7 is a diagram showing a second example of modification of the 3GPP specifications (TS38.304). [Figure 8] FIG. 8 is a diagram showing an example of a change in the 3GPP specifications (TS38.331). [Figure 9] FIG. 9 is a diagram showing an example of a change in the 3GPP specifications (TS38.331). [Figure 10] FIG. 10 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to this embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the functional configuration of a terminal according to this embodiment. [Figure 12] FIG. 12 is a diagram showing an example of a functional block configuration of a base station according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] Fig. 1 is a diagram showing an example of an overview of a wireless communication system according to this embodiment. As shown in Fig. 1, the wireless communication system 1 may include terminals 10, base stations 20, and a core network 30. Note that the numbers of terminals 10 and base stations 20 shown in Fig. 1 are merely examples and are not limited to the numbers shown in the figure.

[0013] The wireless communication system 1 is a system that communicates in accordance with a radio access technology (RAT) defined by 3GPP. The radio access technology that the wireless communication system 1 is compliant with is assumed to be, for example, a fifth-generation RAT such as NR, but is not limited to this. For example, one or more RATs can be used, such as a fourth-generation RAT such as LTE or LTE-Advanced, a sixth-generation or later RAT, or a non-3GPP RAT such as Wi-Fi (registered trademark). Note that the wireless communication system 1 may be configured to communicate in accordance with a radio access technology defined by a standardization organization other than 3GPP (for example, the Institute of Electrical and Electronics Engineers (IEEE) or the Internet Engineering Task Force (IETF)).

[0014] The terminal 10 is a device corresponding to a terminal (e.g., User Equipment (UE)) defined in the 3GPP specifications. The terminal 10 is a predetermined terminal or device, such as a smartphone, a personal computer, a car, an in-vehicle terminal, an in-vehicle device, a stationary device, a telematics control unit (TCU), a sensor, or other IoT device. The terminal 10 may also be called User Equipment (UE), a Mobile Station (MS), a User Terminal, a Radio Apparatus, a subscriber terminal, an access terminal, or the like. The terminal 10 may also be a so-called Reduced Capability (RedCap) terminal, such as an industrial wireless sensor, a surveillance camera, a video service, or a wearable device. The terminal 10 may be either mobile or fixed. The terminal 10 is configured to be capable of communicating using one or more RATs, such as NR, LTE, LTE-Advanced, and Wi-Fi (registered trademark). The terminal 10 is not limited to a terminal specified in the 3GPP specifications, but may be a terminal conforming to a standard specified by another standard development organization. Also, the terminal 10 does not have to be a terminal conforming to a standard.

[0015] The base station 20 is a device equivalent to a base station (e.g., a gNodeB (gNB) or an eNB (E-UTRAN NodeB)) defined in the 3GPP specifications. The base station 20 forms one or more cells C and communicates with the terminal 10 using the cells. The cell C may be interchangeably referred to as a serving cell, a carrier, a component carrier (CC), etc. The cell C may also have a predetermined bandwidth. For example, the base station 20 may communicate with the terminal 10 using one or more cell groups. Each cell group may include one or more cells C. Aggregating multiple cells C within a cell group is called carrier aggregation. The multiple cells C may include a primary cell (PCell) or a primary secondary cell group (SCG) cell (PSCell) and one or more secondary cells (SCG). Furthermore, communicating with the terminal 10 using two cell groups is also called dual connectivity. Note that the terminal 10 is not limited to a base station defined in the 3GPP specifications, and may be a terminal that complies with standards defined by other standardization organizations. Furthermore, the terminal 10 does not have to be a base station that complies with standards.

[0016] The base station 20 may be called a gNodeB (gNB), en-gNB, ng-eNB (next-generation eNB), Next Generation-Radio Access Network (NG-RAN) node, low-power node, Central Unit (CU), Distributed Unit (DU), gNB-DU, Baseband Unit (BBU), Remote Radio Head (RRH), Integrated Access and Backhaul / Backhauling (IAB) node, access point, or the like. The base station 20 is not limited to a single node, and may be configured with multiple nodes (for example, a combination of a lower node such as a DU and an upper node such as a CU). The base stations 20 may be connected to each other via a predetermined interface (for example, an Xn interface).

[0017] 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. An apparatus on the core network 30 (hereinafter also referred to as a "core network apparatus") may perform mobility management such as paging and location registration of the terminal 10. The core network apparatus may be connected to the base station 20 or the terminal 10 via a predetermined interface (for example, an S1 or NG interface).

[0018] The core network device may include, for example, at least one of 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).

[0019] In the wireless communication system 1, a terminal 10 receives a downlink (DL) signal from a base station 20 and / or transmits an uplink (UL) signal to the base station 20. One or more cells C may be configured in the terminal 10, 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.

[0020] Furthermore, the terminal 10 performs a cell search based on a synchronization signal (for example, a primary synchronization signal (PSS) and / or a secondary synchronization signal (SSS)) from the base station 20. The cell search is a procedure in which the terminal 10 acquires time and frequency synchronization in a cell and detects an identifier of the cell (for example, a physical layer cell ID).

[0021] Terminal 10 determines a search space set and / or a control resource set (CORESET) based on parameters (hereinafter referred to as "RRC parameters") included in a Radio Resource Control (RRC) message. CORESET may be configured with frequency domain resources (e.g., a predetermined number of resource blocks) and time domain resources (e.g., a predetermined number of symbols). Note that the RRC parameters may also be called RRC information elements (IEs) or the like.

[0022] The terminal 10 monitors downlink control information (DCI) transmitted via a downlink control channel (for example, a physical downlink control channel (PDCCH)) within a search space set associated with the CORESET. Note that the RRC message may include, for example, an RRC setup message, an RRC reconfiguration message, an RRC resume message, an RRC reestablishment message, system information, etc. Hereinafter, the downlink control channel will be referred to as a PDCCH, but may be called by another name.

[0023] DCI monitoring refers to the terminal 10 blind decoding of PDCCH candidates in a search space set in an assumed DCI format. The number of bits (also referred to as size, bit width, etc.) of a DCI format is predetermined or derived according to the number of bits of a field included in the DCI format. The terminal 10 detects DCI for the terminal 10 based on the number of bits of the DCI format and a specific Radio Network Temporary Identifier (RNTI) used for scrambling (hereinafter referred to as "CRC scrambling") Cyclic Redundancy Check (CRC) bits (also referred to as CRC parity bits) of the DCI format. DCI monitoring is also referred to as PDCCH monitoring, monitor, etc. A given period during which DCI or PDCCH monitoring is performed is also referred to as a PDCCH monitoring occasion.

[0024] The terminal 10 monitors the PDCCH using a search space set in a PDCCH monitoring opportunity, and receives (or detects) DCI that is CRC scrambled by a specific RNTI (e.g., P-RNTI, Cell(C)-RNTI, etc.). The terminal 10 controls reception of a downlink shared channel (e.g., a physical downlink shared channel (PDSCH)) scheduled using the DCI, and / or transmission of an uplink shared channel (e.g., a physical uplink shared channel (PUSCH)). Hereinafter, the downlink shared channel and the uplink shared channel are referred to as PDSCH and PUSCH, but may be called by other names.

[0025] A search space set is a collection of one or more search spaces, and may include a search space set (hereinafter referred to as a "Common search space (CSS) set") that is used in common by one or more terminals 10, and a terminal-specific search space set (UE-specific search space (USS) set). The terminal 10 receives information regarding the configuration of each search space set, and configures each search space set based on the information regarding the configuration.

[0026] For example, the terminal 10 may receive information (hereinafter referred to as "paging search space setting information", for example, the RRC parameter "pagingSearchSpace") related to the setting of a search space set for paging (hereinafter referred to as "paging search space"), and set a paging search space (for example, Type2-PDCCH CSS set) based on the information. The terminal 10 may detect DCI that is CRC scrambled by a specific RNTI (for example, "Paging(P)-RNTI").

[0027] The terminal 10 receives a paging message via a PDSCH scheduled using the DCI. Here, information indicating the P-RNTI may be set by a predefined value. Hereinafter, the paging DCI may be a DCI that is CRC-scrambled by the P-RNTI. Note that the format of the DCI may be, for example, DCI format 1_0. Furthermore, the terminal 10 may receive a short message based on the paging DCI.

[0028] The system information broadcast in cell C may include a Master Information Block (MIB) and / or one or more System Information Blocks (SIB). The MIB is broadcast via a broadcast channel (e.g., a Physical Broadcast Channel (PBCH)). The MIB and SIB1 are also called Minimum System Information, and SIB1 is also called Remaining Minimum System Information (RMSI). SIBx (x = any string such as 2, 3, ...) other than SIB1 are also called Other System Information (OSI). SIBx other than SIB1 and SIB1 are broadcast via PDSCH. SIB1 is cell-specific, and SIBx other than SIB1 may be cell-specific or area-specific including one or more cells.

[0029] A block including at least one of a synchronization signal, a PBCH, and a PBCH demodulation reference signal (DM-RS) is called a synchronization signal block (SSB). An SSB may also be called an SS / PBCH block, an SS block, etc. An SSB may be configured with a predetermined number of symbols (e.g., four consecutive symbols) as a time domain resource and a predetermined number of subcarriers (e.g., 240 consecutive subcarriers) as a frequency domain resource.

[0030] An SS burst set, which is a set of one or more SSBs, is transmitted at a predetermined interval. An SS burst set may also be called an SS burst, etc. Each SSB in the SS burst set is identified by an index (hereinafter referred to as an "SSB index"). In the case of multi-beam operation, SSBs with different indices in the SS burst set correspond to different beams, and may be transmitted by sequentially switching the beam direction through beam sweeping. In the case of single-beam operation, an SSB (one or more SSBs) with a specific index in the SS burst set may be transmitted in all directions.

[0031] (paging) Paging is used for network-initiated connection setup when the terminal 10 is idle or inactive. Paging is also used for short message transmission. The short messages may be used to indicate system information updates and / or Public Warning Systems (PWS). The short messages may also be notified in any state of the terminal 10. Examples of PWS include Earthquake and Tsunami Warning Systems (ETWS), Commercial Mobile Alert Systems (CMAS), etc.

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

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

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

[0035] A terminal 10 in an idle state or an inactive state performs cell selection and resides in a found suitable cell. Furthermore, if the terminal 10 finds a cell (a more suitable cell) that satisfies the cell reselection criteria according to the cell reselection criteria, the terminal 10 resides in the cell.

[0036] Note that "being present in the service area" may also be called "camping." For example, "being present in a cell" may also be called "camping on a cell." Furthermore, a "cell in the service area (serving cell)" may also be called a "camped cell," a "cell that performs synchronization," a "serving cell," a "cell set for terminal 10," etc.

[0037] When the network (e.g., the base station 20 and / or the core network 30) needs to transmit a message to the terminal 10 in an idle state, the network may transmit a short message or a paging message in each cell in a set of areas of a predetermined range including the cell in which the terminal 10 is located. The predetermined area may be referred to as a tracking area (TA). Furthermore, when the network (e.g., the base station 20 and / or the core network 30) needs to transmit a message to the terminal 10 in an inactive state, the network may transmit the paging message in each cell in a RAN notification area (RNA) in which the terminal 10 is located. For example, the network (e.g., the base station 20 and / or the core network 30) may transmit the paging message in a cell with which the terminal 10 last established an RRC connection, and if there is no response from the terminal 10 in the cell, the network may transmit the paging message in another cell in the set of TAs or in the RNA.

[0038] One or more cells are associated with a TA. A TA is identified by a Tracking Area Identifier (TAI). The TAI may be a combination of an identifier indicating a country (Mobile Country Code: MCC), an identifier identifying a network (Mobile Network Code: MNC), and an identifier identifying a tracking area (Tracking Area Code: TAC). The core network 30 may manage the registration area of ​​the terminal 10 in units of a set of TAs.

[0039] When executing a Registration Procedure with the terminal 10, the core network 30 (e.g., AMF) assigns a TAI list indicating a set of TAs as a Registration Area to the terminal 10. The TAI list includes at least the TAI of the TA corresponding to the cell in which the terminal 10 is located. The terminal 10 in an idle state can move within the area set in the TAI list without notifying the core network 30 of the TA in which it is located. Furthermore, if the TAI of the cell in which the terminal 10 is located (current TAI) is not in the TAI list, the terminal 10 notifies the core network 30 (e.g., AMF) that it has moved out of the TAI list (i.e., moved out of the registration area) by executing a Mobility Registration Update Procedure. Upon receiving the notification, the core network 30 updates the TAI list of the terminal 10.

[0040] An RNA covers one or more cells and may be included in a registration area (i.e., a set of TAs) in the core network 30. That is, an RNA may be a subdivision of a registration area, or may be the same as a registration area in the core network 30. An RNA may also be configured by a list of one or more cells, or by a list of at least one RAN area. A RAN area may be a subset of a TA, or may be the same as a TA.

[0041] Information indicating the range of the RNA is set to the terminal 10 by the base station 20 when the terminal 10 transitions to the inactive state. A terminal 10 in the inactive state can move within the area set by the RNA without notifying the base station 20 of the cell in which it is located. The terminal 10 transmits an RNA update (RAN-based notification area update) to the base station 20 periodically, and when a cell that does not belong to the RNA set for the terminal 10 is selected in a cell reselection procedure. The base station 20 (also referred to as the "last serving base station (Last serving gNB)") that instructed the terminal 10 to transition to the inactive state receives a signal related to the terminal 10 from the core network 30 and performs paging in a cell corresponding to the RNA. Furthermore, if the RNA includes a cell of another base station 20 (also referred to as a neighboring base station 20), the base station 20 may transmit a RAN paging message to have the other base station 20 perform paging. Upon receiving the paging signal, the terminal 10 in the inactive state resumes the RRC connection and transitions to the connected state.

[0042] Paging initiated by the core network 30 for a terminal 10 in an idle state may be referred to as "CN paging." Paging initiated by the base station 20 for a terminal 10 in an inactive state may be referred to as "RAN paging."

[0043] The system information (e.g., SIB1) may include a tracking area identifier (e.g., TAC), a RAN area identifier (e.g., RAN-AreaCode), and a cell identifier (CellIdentity). That is, by receiving the system information, the terminal 10 can identify the TA and RAN area of ​​the cell in which it is located.

[0044] The terminal 10 performs discontinuous reception (DRX) to reduce power consumption. Specifically, the terminal 10 performs PDCCH monitoring at paging occasions (POs) and can sleep during periods other than the POs.

[0045] A PO is a given period consisting of one or more time units (for example, one or more symbols, one or more slots, or one or more subframes). A PO may be composed of, for example, a set of one or more PDCCH monitoring opportunities. A PO may be provided at a given period. A PO may be provided within a paging frame (PF). A radio frame (RF) constituting a PF is a given time unit (for example, a time unit consisting of 10 subframes) and is identified by an identification number (hereinafter referred to as a "system frame number (SFN)"). One or more PFs may be provided within a DRX period. A DRX period is also called a paging cycle.

[0046] Fig. 2 is a diagram showing an example of a PO according to this embodiment. As shown in Fig. 2, a PF is arranged every predetermined number of RFs (here, 8 RFs) within a DRX cycle (here, 32 RFs).

[0047] The terminal 10 controls the establishment of a connection with the network side (for example, the base station 20 and / or the core network 30) based on a list of one or more terminal identifiers in a paging message received in a PO (for example, an RRC parameter "pagingRecordList") and a terminal identifier assigned to the terminal 10. For example, the terminal 10 may start a procedure for establishing a connection with the network side when the list includes a terminal identifier assigned to the terminal 10. Here, the terminal identifier is an identifier of the terminal 10, and may be, for example, a 5G-S-TMSI or may be determined based on the 5G-S-TMSI.

[0048] Even if the terminal 10 receives a paging DCI, it cannot determine which terminal 10 the paging is addressed to unless it decodes the list of terminal identifiers in the paging message. Therefore, the terminal 10 needs to perform a process for determining for each PO whether paging is addressed to that terminal 10. As a result, terminals 10 that are not targeted for paging may waste power.

[0049] (P.E.I.) Currently, in 3GPP, in order to reduce wasteful power consumption of terminals 10 that are not the target of paging, it is being considered to notify the terminals 10 of PEI information related to paging in one or more POs and to control the terminal operations in the PO based on the PEI information. For example, it is being considered to divide a group made up of multiple terminals 10 that use the same PO into multiple subgroups and include information on the subgroups that are the target of paging in the PO (hereinafter referred to as "subgroup information") in the PEI information.

[0050] The subgrouping of the terminals 10 may be performed on a terminal identifier basis or on a network basis. The PEI information may be referred to as a "PEI."

[0051] In the terminal identifier-based case, the terminal 10 may determine the subgroup allocated to itself based on the terminal identifier or UE_ID. Specifically, the terminal 10 may determine the identifier of the subgroup (hereinafter referred to as "subgroup ID") based on at least one of the number N of PFs in the DRX cycle T, the number Ns of POs per PF, and the total number Nsg of subgroups, in addition to the terminal identifier.

[0052] On the other hand, in the network-based case, the base station 20 or the core network 30 may determine a subgroup to be assigned to the terminal 10 based on information managed on the network side (e.g., the mobility state of the terminal 10, the paging probability, and / or the power consumption profile of the terminal 10, attributes of the terminal 10 related to the amount of movement, etc.). The base station 20 or the core network 30 may notify the terminal 10 of information indicating the determined subgroup (e.g., a subgroup ID) by using a NAS (Network Access Stratum) message, an RRC message, etc.

[0053] The subgroup information may be, for example, information (e.g., a 1-bit value) indicating whether paging is performed for each subgroup (i.e., whether paging is performed for each subgroup or for each group). Alternatively, the subgroup information may be information indicating which subgroups in one or more POs are to be paging targets (hereinafter referred to as "paging sub-group indication information"). Note that one or more POs may be included in a single PF, or may be included in multiple PFs. For example, a PEI may correspond to up to four POs in one PF.

[0054] For example, the paging subgroup indication information may divide the terminals 10 sharing each PO into a predetermined number of subgroups (e.g., a maximum of eight subgroups) and indicate whether each subgroup is a paging target in each PO (whether or not a paging message is sent to each subgroup). The paging subgroup indication information may be, for example, a bitmap with a number of bits corresponding to the number of subgroups in one or more POs, or may be information indicating identifiers of subgroups to be paging targets in each PO.

[0055] The PEI information may be included in DCI transmitted on the PDCCH. DCI including the PEI information is also called "PEI DCI," "first downlink control information," etc. The PEI DCI may include information related to a short message in addition to the PEI information. The PEI DCI may be in DCI format 2_7.

[0056] The terminal 10 may determine the time position of a PDCCH monitoring opportunity (hereinafter referred to as "PEI-O") for a PEI DCI based on a PO (hereinafter referred to as "target PO") indicating which subgroup is to be paged 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 a PF including the target PO. Alternatively, the time position of the PEI-O may be determined based on an SSB or SS burst before the target PO. The SS burst may be, for example, the Lth (e.g., L=1, 2, or 3) SS burst before 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.

[0057] Fig. 3 is a diagram showing an example of the relationship between a PEI-O and a PO according to this embodiment. As shown in Fig. 3, a search space set (hereinafter referred to as "PEI search space") used for monitoring a PEI DCI may be provided in the PEI-O. A PEI DCI detected by monitoring the PEI search space may correspond to one or more POs (for example, up to four POs per PF). Note that one PEI DCI may correspond to multiple POs across multiple PFs, or may correspond to one or more POs within a single PF. Furthermore, one PO may correspond to multiple PEI DCIs.

[0058] For example, in FIG. 3, the start timing of the PF including POs #0 and #1 is set as the reference time, and the start timing of the PEI-O is determined using a time offset (for example, a time offset of the RF level) relative to the reference time.

[0059] 3, a terminal 10 in an idle state or an inactive state detects a PEI DCI by monitoring a PEI search space. The terminal 10 skips monitoring the paging search space in PO#0 based on the subgroup information in the PEI DCI. Meanwhile, the terminal 10 monitors paging DCI (also referred to as "second downlink control information") in the paging search space in PO#1 based on the subgroup information in the PEI DCI.

[0060] Note that the PEI information may not indicate whether paging is performed for each subgroup, but may simply indicate whether paging is performed. For example, subgrouping of terminals 10 may be optional and not required. When terminals 10 are not subgrouped, the PEI information may be information indicating whether a paging message is transmitted in one or more POs associated with the PEI information. Furthermore, when receiving PEI information, the terminal 10 may skip monitoring of paging DCI in the paging search space in one or more POs associated with the received PEI information.

[0061] As described above, the terminal 10 that has received the PEI information can skip monitoring the paging DCI in the PO, thereby reducing the power consumption of the terminal 10. On the other hand, the base station 20 transmits the PEI information in the PEI-O before the PO in addition to conventional paging, which increases the amount of radio resources consumed. Furthermore, paging is performed for each cell included in the TAI list or RNA in which the terminal 10 is located. However, transmitting the PEI information in multiple cells each time paging is performed further increases the amount of radio resources consumed. Therefore, in order to solve this problem, it is desirable to appropriately control the transmission and reception of PEI information, taking into consideration the balance between reducing the power consumption of the terminal 10 and increasing the amount of radio resources consumed.

[0062] Therefore, in this embodiment, information about the cell in which the PEI information is transmitted (hereinafter referred to as "PEI transmission area information") is set in the terminal 10, and the terminal 10 controls in which cell the PEI information is to be monitored according to the information. Also, the base station 20 controls whether or not to transmit the PEI information when performing paging according to the information.

[0063] (Transmission of PEI transmission area information via system information) FIG. 4 is a diagram showing a method for transmitting PEI transmission area information using system information. Base station 20-1 (first base station) and base station 20-2 (second base station) that support the transmission of PEI information broadcast system information including PEI transmission area information. Here, the area where the PEI is transmitted (hereinafter referred to as the "PEI transmission area") indicated by the PEI transmission area information may be one of the following two patterns. Note that the PEI transmission area can also be referred to as the "cell where the PEI is transmitted" or the "PEI transmission cell." Transmission area pattern 1: PEI information is transmitted in the cell where the RRC connection is released (hereinafter referred to as the "last cell" or "last used cell"). The last cell may be called the cell where the terminal 10 transitioned from the connected state to the idle state or the inactive state, or the cell where the RRC release message was received. It may also be called the cell where the terminal 10 last transitioned from the connected state to the idle state or the inactive state, or the cell where the RRC release message was last received. Transmission area pattern 2: PEI information is transmitted in cells included in the RNA or TAI list. In this pattern, the terminal 10 may recognize that the PEI information is transmitted in each cell in the RNA when in an inactive state, and that the PEI information is transmitted in each cell in the TAI list when in an idle state.

[0064] In this embodiment, the terminal 10 may execute either or both of a method of controlling whether to monitor the PEI DCI in accordance with the PEI transmission area information broadcast in the serving cell (hereinafter referred to as the "method based on the broadcast information of the serving cell") and a method of controlling whether to monitor the PEI DCI in accordance with the PEI transmission area information broadcast in the last cell (hereinafter referred to as the "method based on the broadcast information of the last cell").

[0065] The "method based on broadcast information of the serving cell" and the "method based on broadcast information of the last cell" will be specifically described below. In the following description, it is assumed that the terminal 10 transitions to an idle state or an inactive state in the cell C1 (i.e., the cell C1 is the last cell), and then moves while remaining in the idle state or the inactive state, and reselects the cell C2.

[0066] <Method based on broadcast information of serving cell> If the serving cell falls within the PEI transmission area indicated by the PEI transmission area information broadcast by the serving cell, the terminal 10 assumes that the PEI information is transmitted by the serving cell. On the other hand, if the serving cell does not fall within the PEI transmission area indicated by the PEI transmission area information broadcast by the serving cell, the terminal 10 assumes that the PEI information is not transmitted by the serving cell.

[0067] <<Case where PEI transmission area information for transmission area pattern 1 is broadcast in the serving cell>> In this case, the terminal 10 assumes that if the serving cell is the last cell, the PEI information is transmitted in the serving cell, whereas if the serving cell is not the last cell, the terminal 10 assumes that the PEI information is not transmitted in the serving cell.

[0068] For example, in Fig. 4, it is assumed that PEI transmission area information indicating transmission area pattern 1 is broadcast in each of cells C1 and C2. First, while the terminal 10 is present in cell C1, it acquires the PEI transmission area information broadcast in cell C1. Next, the terminal 10 assumes whether or not to transmit PEI information based on the acquired PEI transmission area information. Since the serving cell (cell C1) is the last cell, the terminal 10 assumes that PEI information will be transmitted while the terminal 10 is present in cell C1, and monitors PEI DCI (first downlink control information) in the PEI search space (first search space set) of PEI-O.

[0069] Next, the terminal 10 reselects cell C2 and acquires PEI transmission area information broadcast in cell C2. Based on the acquired PEI transmission area information, the terminal 10 assumes whether or not to transmit PEI information. Because the serving cell (cell C2) is not the last cell, the terminal 10 assumes that PEI information will not be transmitted while the terminal 10 is serving cell C2, and monitors paging DCI (second downlink control information) in the paging search space (second search space set) of the PO without monitoring PEI DCI.

[0070] <<Case where PEI transmission area information for transmission area pattern 2 is broadcast in the serving cell>> In this case, the terminal 10 assumes that if the serving cell is included in the RNA or TAI list, the PEI information is transmitted in the serving cell, whereas if the serving cell is not included in the RNA or TAI list, the terminal 10 assumes that the PEI information is not transmitted in the serving cell.

[0071] For example, in FIG. 4, it is assumed that PEI transmission area information indicating transmission area pattern 2 is broadcast in cells C1 and C2, respectively. It is also assumed that cells C1 and C2 are included in the cells in the RNA or TAI list set in the terminal 10. First, while the terminal 10 is present in cell C1, it acquires the PEI transmission area information broadcast in cell C1. Next, based on the acquired PEI transmission area information, the terminal 10 determines whether or not to transmit PEI information. Because the serving cell (cell C1) is included in the RNA or TAI list, the terminal 10 assumes that PEI information is transmitted while it is present in cell C1, and monitors PEI DCI in the PEI search space of PEI-O.

[0072] Next, the terminal 10 reselects cell C2 and acquires PEI transmission area information broadcast in cell C2. Based on the acquired PEI transmission area information, the terminal 10 assumes whether or not PEI information will be transmitted. Because the serving cell (cell C2) is included in the RNA or TAI list, the terminal 10 assumes that PEI information will be transmitted while the terminal 10 is serving cell C2, and monitors PEI DCI in the PEI search space of PEI-O.

[0073] <Method based on last cell notification information> If the serving cell corresponds to the PEI transmission area indicated by the PEI transmission area information broadcast by the last cell, the terminal 10 assumes that the PEI information is transmitted in the serving cell. On the other hand, if the serving cell does not correspond to the PEI transmission area indicated by the PEI transmission area information broadcast by the last cell, the terminal 10 assumes that the PEI information is not transmitted in the serving cell.

[0074] In the "method based on broadcast information of the last cell," the terminal 10 acquires and stores the PEI transmission area information broadcast by the last cell, and continues to store the PEI transmission area information while the idle state and the inactive state continue. In this case, after acquiring the PEI transmission area information from the last cell, the terminal 10 may not acquire the PEI transmission area information from the system information acquired in the reselected cell until the next transition to the connected state. This can further reduce the power consumption of the terminal 10.

[0075] <<Case where PEI transmission area information of transmission area pattern 1 is broadcast in the last cell>> In this case, the terminal 10 assumes that if the serving cell is the last cell, the PEI information is transmitted, whereas if the serving cell is not the last cell, the terminal 10 assumes that the PEI information is not transmitted in the serving cell.

[0076] For example, in Fig. 4, it is assumed that PEI transmission area information indicating transmission area pattern 1 is broadcast in each of cells C1 and C2. First, terminal 10 acquires the PEI transmission area information broadcast in cell C1. Next, terminal 10 assumes whether or not to transmit PEI information based on the acquired PEI transmission area information. Because the serving cell (cell C1) is the last cell, terminal 10 assumes that PEI information will be transmitted while the terminal 10 is serving cell C1, and monitors PEI DCI in the PEI search space of PEI-O.

[0077] Next, the terminal 10 reselects cell C2. The terminal 10 assumes whether to transmit PEI information based on the PEI transmission area information acquired from the last cell. Because the serving cell (cell C2) is not the last cell, the terminal 10 assumes that PEI information will not be transmitted while the terminal 10 is serving cell C2, and therefore monitors paging DCI in the paging search space of the PO without monitoring PEI DCI.

[0078] <<Case where PEI transmission area information of transmission area pattern 2 is broadcast in the last cell>> The terminal 10 assumes that if the serving cell is a cell in the RNA or TAI list, the PEI information is transmitted in the serving cell, whereas if the serving cell is not a cell in the RNA or TAI list, the terminal 10 assumes that the PEI information is not transmitted in the serving cell.

[0079] For example, in Fig. 4, it is assumed that PEI transmission area information indicating transmission area pattern 2 is broadcast in cells C1 and C2, respectively. It is also assumed that cells C1 and C2 are included in the cells in the RNA or TAI list set in the terminal 10. First, the terminal 10 acquires the PEI transmission area information broadcast in cell C1. Next, the terminal 10 assumes whether or not to transmit PEI information based on the acquired PEI transmission area information. Because the serving cell (cell C1) is included in the RNA or TAI list, the terminal 10 assumes that PEI information is transmitted while the terminal 10 is serving cell C1, and monitors the PEI DCI in the PEI search space of PEI-O.

[0080] Next, the terminal 10 reselects cell C2. The terminal 10 assumes whether or not to transmit PEI information based on the PEI transmission area information acquired from the last cell. Because the serving cell (cell C2) is included in the RNA or TAI list, the terminal 10 assumes that PEI information will be transmitted while the terminal 10 is serving cell C2, and monitors the PEI DCI in the PEI search space of PEI-O.

[0081] <<Additional notes>> Note that if a terminal 10 in an inactive state selects a cell that does not belong to the RNA set for the terminal 10 in the reselection procedure, the terminal 10 transmits an RNA update to the base station 20, and the RNA set for the terminal 10 is updated to an RNA that includes the selected cell. Similarly, if a terminal 10 in an idle state selects a cell that does not belong to the TAI list set for the terminal 10 in the reselection procedure, the terminal 10 executes a registration update procedure, and the TAI list set for the terminal 10 is updated to a TAI list that includes the selected cell. In other words, if the RNA and TAI lists are updated normally, this does not occur if the serving cell is not included in the RNA or TAI list. Therefore, in the "method based on broadcast information of a serving cell" and the "method based on broadcast information of a last cell," in a case where the serving cell broadcasts PEI transmission area information of transmission area pattern 2, the terminal 10 may simply assume that PEI information is transmitted from each cell without determining whether the serving cell is included in the RNA or TAI list.

[0082] (Processing procedure between terminal and base station) Fig. 5 is a sequence diagram showing an example of a processing procedure performed by the terminal 10 and the base station 20. In Fig. 5, it is assumed that the base station 20-1 forms a cell C1, and the base station 20-2 forms a cell C2. It is also assumed that the terminal 10 is in a connected state and is present in the cell C1. Steps S112 to S114 in Fig. 5 are executed when the terminal 10 is in an inactive state. In Fig. 5, when there is no need to distinguish between the base stations 20-1 and 20-2, they are referred to as the base stations 20.

[0083] In step S100, terminal 10 located in cell C1 acquires system information transmitted from base station 20-1 and stores the acquired system information in its own memory. The acquisition and storage of system information by terminal 10 may be referred to as system information being set in terminal 10. The system information includes various setting information related to the PEI (hereinafter referred to as "PEI setting information" or "second information"). The PEI setting information may include information indicating whether or not a cell supports PEI transmission (whether or not it supports PEI). Furthermore, if the system information includes PEI setting information, it may mean that the cell supports PEI transmission, and if the system information does not include PEI setting information, it may mean that the cell does not support PEI transmission.

[0084] Furthermore, the PEI transmission area information may be included in the PEI setting information. That is, the PEI transmission area information may be part of various setting information related to the PEI. Furthermore, the PEI transmission area information may be information that explicitly or implicitly indicates which of the above-mentioned transmission area patterns 1 and 2 the PEI transmission area corresponds to. For example, the PEI transmission area information may be information that explicitly indicates transmission area pattern 1 or transmission area pattern 2. Alternatively, when the PEI transmission area information is included in the PEI setting information (or system information), it may mean that the PEI is transmitted with transmission area pattern 1, and when the PEI transmission area information is not included in the PEI setting information (or system information), it may mean that the PEI is transmitted with transmission area pattern 2. Alternatively, when the PEI transmission area information is not included in the PEI setting information (or system information), it may mean that the PEI is transmitted with transmission area pattern 1, and when the PEI transmission area information is included in the PEI setting information (or system information), it may mean that the PEI is transmitted with transmission area pattern 2.

[0085] The PEI setting information may be included in SIB1 or in SIB2 or later. Since SIB1 includes various information related to paging such as a paging cycle, the terminal 10 can efficiently acquire information related to paging and the PEI setting information by receiving SIB1.

[0086] In step S101, when the base station 20 transitions the terminal 10 to an idle state, the base station 20 transmits an RRC release message. When the base station 20 transitions the terminal 10 to an inactive state, the base station 20 transmits an RRC release message including a parameter (e.g., SuspendConfig) indicating configuration information related to the inactive state. The parameter may include information related to the RNA (e.g., RAN-NotificationAreaInfo). The information related to the RNA may be represented by a list of cell identifiers of cells included in the RNA (e.g., PLMN-RAN-AreaCellList) or a list of RAN area codes (RAN-AreaCode) included in the RNA (e.g., ran-AreaCodeList). After receiving the RRC release message and transitioning to the idle state or the inactive state, the terminal 10 memorizes that the last cell is cell C1 (e.g., memorizes the cell identifier of cell C1 as the identifier of the last cell).

[0087] In step S102, the terminal 10 that has transitioned to the idle state or the inactive state monitors the PEI DCI and / or the paging DCI according to the "method based on the broadcast information of the serving cell" or the "method based on the broadcast information of the last cell" described above. Note that, if the serving cell supports PEI transmission (for example, if the system information includes PEI setting information), the terminal 10 may monitor the PEI DCI according to the "method based on the broadcast information of the serving cell" or the "method based on the broadcast information of the last cell." Furthermore, if the serving cell does not support PEI transmission (for example, if the system information does not include PEI setting information), the terminal 10 may assume that the serving cell does not transmit PEI, and may monitor the paging DCI without monitoring the PEI DCI.

[0088] In step S110, when transmitting a paging message to the terminal 10, the base station 20-1 determines whether to transmit PEI information (more specifically, PCI DCI including PEI information) before transmitting the paging message based on the PEI transmission area information set for itself. Hereinafter, the method of determining whether to transmit PEI information will be described separately for the case where the terminal 10 is in an idle state and the case where the terminal 10 is in an inactive state.

[0089] <When the device is idle> Assume that the PEI transmission area in the base station 20-1 is set to transmission area pattern 1 (PEI information is transmitted in the last cell), and that information about the last cell included in the paging message received from the core network 30 indicates a cell formed by the base station 20-1. In this case, the base station 20-1 may determine to transmit the PEI information in the last cell among the cells for performing paging. Also assume that the PEI transmission area in the base station 20-1 is set to transmission area pattern 1, and that information about the last cell included in the paging message received from the core network 30 does not indicate a cell formed by the base station 20-1. In this case, the base station 20-1 may determine not to transmit the PEI information in the cell for performing paging.

[0090] Furthermore, when the PEI transmission area is set to transmission area pattern 2 (transmitting PEI information using a TAI list or RNA) in the base station 20, the base station 20 may determine to transmit the PEI information in the cell where paging is performed. That is, in the example of Fig. 5, the base station 20-1 may determine to transmit the PEI information when the PEI transmission area is set to transmission area pattern 2.

[0091] <When the device is inactive> When the PEI transmission area in the base station 20-1 is set to transmission area pattern 1 (PEI information is transmitted in the last cell), the base station 20-1 may determine to transmit the PEI information in the last cell among the cells that perform paging (in the example of FIG. 5, cell C1 is the last cell, so the base station 20-1 determines to transmit the PEI information in cell C1). Also, the base station 20-1 may determine not to transmit the PEI information in cells other than the last cell. Also, when the PEI transmission area in the base station 20-1 is set to transmission area pattern 2 (PEI information is transmitted in the TAI list or RNA), the base station 20-1 may determine to transmit the PEI information in the cell that performs paging, regardless of which cell is the last cell.

[0092] In step S111, the base station 20-1 transmits the PEI DCI (PEI DCI including subgroup information indicating the subgroup of the terminal 10, if the base station 20-1 supports subgroups) in the PEI search space of the PEI-O in the cell where it has decided to transmit the PEI information. Furthermore, the base station 20-1 transmits the paging DCI in the paging search space of the PO corresponding to the PEI DCI (PO corresponding to the subgroup of the terminal 10, if the base station 20-1 supports subgroups), and also transmits a paging message including the terminal identifier of the terminal 10 via the PDSCH scheduled in the paging DCI.

[0093] On the other hand, in the cell where the base station 20-1 has decided not to transmit PEI information, it transmits paging DCI in the paging search space of the PO and transmits a paging message including the terminal identifier of the terminal 10 via the PDSCH scheduled in the paging DCI.

[0094] In step S112, the base station 20-1 transmits a paging message to the base station 20-2 to cause the other base stations 20-2 forming the respective cells in the RNA to perform paging.

[0095] In step S113, the base station 20-2 determines whether to transmit PEI information before transmitting a paging message. Note that paging for the terminal 10 in the inactive state is performed starting from the base station 20 that transitioned the terminal 10 to the inactive state, and therefore the cell of the base station 20 that received the paging message from another base station 20 does not correspond to the last cell. Therefore, when the PEI transmission area is set to transmission area pattern 1 (transmitting PEI information in the last cell) in the system information of the base station 20-2, the base station 20-2 that received the paging message from the base station 20-1 may determine not to transmit PEI information in the cell in which paging is performed.

[0096] Furthermore, when the PEI transmission area is set to transmission area pattern 2 (PEI information is transmitted using the TAI list or RNA) in the base station 20, it may be determined to transmit the PEI information in the cell where paging is performed. That is, in the example of Fig. 5, the base station 20-2 may determine to transmit the PEI information when the PEI transmission area is set to transmission area pattern 2.

[0097] In step S114, the base station 20-2 transmits the PEI DCI (PEI DCI including subgroup information indicating the subgroup of the terminal 10, if the base station 20-2 supports subgroups) in the PEI search space of the PEI-O in the cell where it has decided to transmit the PEI information. Furthermore, the base station 20-2 transmits the paging DCI in the paging search space of the PO corresponding to the PEI DCI (PO corresponding to the subgroup of the terminal 10, if the base station 20-2 supports subgroups), and also transmits a paging message including the terminal identifier of the terminal 10 via the PDSCH scheduled in the paging DCI.

[0098] On the other hand, in the cell where the base station 20-2 has decided not to transmit PEI information, it transmits paging DCI in the paging search space of the PO and transmits a paging message including the terminal identifier of the terminal 10 via the PDSCH scheduled in the paging DCI.

[0099] According to the processing procedure described above, the terminal 10 monitors the PEI-O within the range of the set PEI transmission area and does not monitor the PEI-O outside the range of the set PEI transmission area. Furthermore, the base station 20 transmits PEI information within the range of the set PEI transmission area and does not transmit the PEI information outside the range of the set PEI transmission area. This allows the terminal 10 and the base station 20 to recognize the cell from which the PEI information is transmitted and appropriately control the transmission and reception of the PEI information. Furthermore, according to the "method based on broadcast information of the serving cell," a PEI transmission area can be specified for each cell, making it possible to flexibly specify whether or not to transmit the PEI depending on the load of each cell. On the other hand, according to the "method based on broadcast information of the last cell," the terminal 10 only needs to check the system information of the cell in which it was last connected. Therefore, it is not necessary to check the PEI transmission area information included in the system information of the cell reselected after transitioning to the idle state or the inactive state. This makes it possible to further reduce the power consumption of the terminal 10.

[0100] (Example of specification change) FIG. 6 is a diagram showing a first example of a modification to the 3GPP specification (TS38.304). This modification corresponds to a "method based on broadcast information of a serving cell." Note that the following modification is merely an example, and the modification is not limited to the one described below. As shown in FIG. 6, when the system information includes PEI setting information, the terminal 10 may monitor the PEI information using PEI parameters (various parameters included in the PEI setting information) included in the system information. Furthermore, when "lastUsedCellOnly" is set in SIB1, the terminal 10 may use the PEI only in the cell that most recently transitioned to the idle state or the inactive state. On the other hand, when "lastUsedCellOnly" is not set in SIB1, the terminal 10 may use the PEI regardless of whether the cell most recently transitioned to the idle state or the inactive state. Whether the PEI transmission area information indicates transmission area pattern 1 (PEI transmission in the last cell) or transmission area pattern 2 (PEI transmission in the TAI list or RNA) may be determined based on whether the "lastUsedCellOnly" parameter is set in SIB1. For example, if the "lastUsedCellOnly" parameter is set in SIB1, transmission area pattern 1 may be indicated, and if the "lastUsedCellOnly" parameter is not set in SIB1, transmission area pattern 2 may be indicated.

[0101] FIG. 7 is a diagram showing a second modification of the 3GPP specification (TS38.304). This modification corresponds to a "method based on broadcast information of the last cell." As shown in FIG. 7, when the system information includes PEI setting information, the terminal 10 may monitor the PEI information using PEI parameters (various parameters included in the PEI setting information) included in the system information. Furthermore, when "lastUsedCellOnly" is set in the SIB1 of the cell that most recently transitioned to the idle state or the inactive state, the terminal 10 may use the PEI only in the cell (the cell that most recently transitioned to the idle state or the inactive state). On the other hand, when "lastUsedCellOnly" is not set in the SIB1 of the cell that most recently transitioned to the idle state or the inactive state, the terminal 10 may use the PEI regardless of whether the cell is the cell that most recently transitioned to the idle state or the inactive state. In addition, the terminal 10 may check whether "lastUsedCellOnly" is set in SIB1 only once while in the idle state or in the inactive state (for example, only once in the cell that has transitioned to the idle state or the inactive state), and the instruction based on this setting may remain valid until the terminal 10 transitions to the connected state.

[0102] 8 and 9 are diagrams showing examples of changes to the 3GPP specifications (TS38.331). Also, an example of explanation of the information added in FIG. 8 is shown in FIG.

[0103] As shown in FIG. 8, the "DownlinkConfigCommonSIB" included in SIB1 includes PEI configuration information (e.g., pei-Config-r17), and the PEI configuration information may include PEI transmission area information (e.g., lastUsedCellOnly). When the PEI configuration information (e.g., pei-Config-r17) is included in SIB1, it may indicate that PEI transmission is supported in the serving cell. Furthermore, if the PEI transmission area information (e.g., lastUsedCellOnly) is present, the terminal 10 may use the PEI only in the cell that most recently transitioned to the idle state or the inactive state, and if not (if lastUsedCellOnly is not present), the terminal 10 may use the PEI regardless of whether the cell is the cell that most recently transitioned to the idle state or the inactive state.

[0104] (Wireless communication system configuration) Next, we will explain the configuration of each device in the above-described wireless communication system 1. Note that the following configuration is intended to show the configuration necessary for explaining this embodiment, and does not exclude each device from having a functional block other than that shown.

[0105] <Hardware configuration> 10 is a diagram showing 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 (e.g., terminal 10, base station 20, core network 30, etc.) includes a processor 11, a storage device 12, a communication device 13 for performing wired or wireless communication, and an input device 14 for accepting various input operations and outputting various information.

[0106] 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 execute 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 configured with one or more processors 11. Furthermore, each device may be called a computer.

[0107] The storage device 12 is configured by, for example, storage such as a memory, a hard disk drive (HDD), and / or a solid state drive (SSD), etc. The storage device 12 may store various information necessary for the processor 11 to execute processing (for example, a program executed by the processor 11, etc.).

[0108] 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 performs processing related to wireless signals, and a BB (BaseBand) device that performs baseband signal processing.

[0109] The RF device generates a radio signal to be transmitted from an antenna by, for example, performing D / A conversion, modulation, frequency conversion, power amplification, etc. on a digital baseband signal received from the BB device. The RF device also generates a digital baseband signal by performing frequency conversion, demodulation, A / D conversion, etc. on the radio signal received from the antenna, and transmits it to the BB device.

[0110] The BB device performs a process of converting data into a digital baseband signal. Specifically, the BB device may map the data to subcarriers, perform IFFT to generate OFDM symbols, insert CPs into the generated OFDM symbols, and generate digital baseband signals. Note that the BB device may apply a transform precoder (DFT spreading) before mapping the data to the subcarriers.

[0111] Furthermore, the BB device performs a process of converting the digital baseband signal into data. Specifically, the BB device may remove CP from the digital baseband signal input from the RF device, perform FFT on the signal from which the CP has been removed, and extract a signal in the frequency domain. Note that the BB device may also apply IDFT to the signal in the frequency domain.

[0112] The input / output device 14 includes, for example, input devices such as a keyboard, a touch panel, a mouse, and / or a microphone, and output devices such as a display and / or a speaker.

[0113] The hardware configuration described above is merely an example. Each device in the wireless communication system 1 may omit some of the hardware shown in Fig. 10, or may include hardware not shown in Fig. 10. Furthermore, the hardware shown in Fig. 10 may be configured using one or more chips.

[0114] <Function block configuration> Terminal Fig. 11 is a diagram showing an example of the functional configuration of a terminal according to this embodiment. As shown in Fig. 11, the terminal 10 includes a receiving unit 101, a transmitting unit 102, and a control unit 103. The functional configuration shown in Fig. 11 is merely an example, and the functional divisions and names of the functional units may be any names as long as they can execute the operations according to this embodiment. Furthermore, the receiving unit 101 and the transmitting unit 102 may be collectively referred to as a communication unit.

[0115] 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. 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 storing the program may be a non-transitory computer-readable medium. The non-transitory storage medium is not particularly limited, and may be, for example, a storage medium such as a USB memory or a CD-ROM.

[0116] The receiving unit 101 receives a signal (e.g., a DL signal and / or a sidelink signal). The receiving unit 101 may also receive information and / or data transmitted via the signal. Here, "receiving" may include, for example, performing reception-related processing such as at least one of reception, demapping, demodulation, decoding, monitoring, and measurement of a radio signal. The DL signal may include, for example, at least one of a PDSCH, a PDCCH, a downlink reference signal, a synchronization signal, a PBCH, and the like.

[0117] The receiving unit 101 monitors PDCCH candidates within the search space to detect DCI. The receiving unit 101 may receive DL data via a PDSCH scheduled using the DCI. The DL data may include downlink user data and / or control information of higher layers (e.g., at least one parameter of a MAC layer, an RRC layer, and a Non Access Stratum (NAS) layer). The receiving unit 101 may receive system information via a PBCH and / or a PDSCH.

[0118] The transmitter 102 transmits a signal (e.g., an UL signal and / or a sidelink signal). The transmitter 102 may also transmit information and / or data transmitted via the signal. Here, "transmitting" may include, for example, performing processing related to transmission, such as at least one of encoding, modulation, mapping, and transmission of a radio signal. The UL signal may include, for example, at least one of a PUSCH, a PRACH, a PUCCH, an uplink reference signal, etc.

[0119] The transmitter 102 may transmit UL data via a PUSCH scheduled using the DCI received by the receiver 101. The UL data may transmit uplink user data and / or control information of higher layers (for example, at least one parameter of the MAC layer, the RRC layer, and the NAS layer).

[0120] The control unit 103 performs various controls in the terminal 10. Specifically, the control unit 103 may control the operation of the terminal 10 based on information relating to various configurations (for example, parameters of the RRC layer) received by the receiving unit 101 from the base station 20 or another terminal 10. The operation of the terminal 10 based on the information may be synonymous with "configuration information being configured in the terminal 10."

[0121] The control unit 103 may control reception of signals in the receiving unit 101. The control unit 103 may also control transmission of signals in the transmitting unit 102. The control unit 103 may determine whether to apply a transform precoder to signals transmitted by the transmitting unit 102.

[0122] In this embodiment, the terminal 10 may include: a receiving unit 101 that receives system information including second information (e.g., PEI setting information, the same applies hereinafter) related to a cell to which first information (e.g., PEI information, the same applies hereinafter) related to paging at one or more paging occasions is transmitted; and a control unit 103 that, when in an idle state or an inactive state, controls, based on the system information received in a serving cell or a cell that has transitioned to the idle state or the inactive state (or based on the second information included in the system information), whether or not to monitor downlink control information (e.g., PEI DCI, first downlink control information, the same applies hereinafter) including the first information, in the serving cell. Note that the method of controlling whether or not to monitor the first downlink control information based on the system information received in the serving cell corresponds to the "method based on broadcast information of the serving cell." Furthermore, the method of controlling whether or not to monitor the first downlink control information based on the system information received in a cell that has transitioned to the idle state or the inactive state corresponds to the "method based on broadcast information of the last cell."

[0123] When information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state (for example, PEI transmission area information indicating transmission area pattern 1) is set in the second information included in the system information received by the serving cell, if the serving cell is the same as the cell that has transitioned to an idle state or an inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell when the serving cell is the same as the cell that has transitioned to an idle state or an inactive state, and may not monitor the downlink control information including the first information in the serving cell when the serving cell is not the same as the cell that has transitioned to an idle state or an inactive state. This processing corresponds to a case in which the PEI transmission area information of transmission area pattern 1 is broadcast in the serving cell in the "method based on broadcast information of a serving cell."

[0124] When information indicating that the cell to which the first information is transmitted is a cell in a RAN notification area or a cell in a tracking area list (for example, PEI transmission area information indicating transmission area pattern 2) is set in the second information included in the system information received by the serving cell, the control unit 103 may monitor the downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to the idle state or the inactive state. This processing corresponds to the case in which the PEI transmission area information of transmission area pattern 2 is broadcast in the serving cell in the "method based on broadcast information of the serving cell."

[0125] When the second information included in the system information received by the serving cell does not include information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to an idle state or an inactive state. Furthermore, when the system information includes information indicating that the cell supports transmission of the first information and the second information included in the system information received by the serving cell does not include information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to an idle state or an inactive state. This processing corresponds to the PEI transmission area indicating transmission area pattern 2 when PEI transmission area information is not included in the PEI setting information (or system information) in the "method based on broadcast information of a serving cell."

[0126] When information indicating that the cell to which the first information is transmitted is the cell that has transitioned to the idle state or the inactive state is set in the second information included in the system information received by the cell that has transitioned to the idle state or the inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell if the serving cell is the same as the cell that has transitioned to the idle state or the inactive state, and may not monitor the downlink control information including the first information in the serving cell if the serving cell is not the same as the cell that has transitioned to the idle state or the inactive state. This processing corresponds to the case in which the PEI transmission area information of transmission area pattern 1 is broadcast in the last cell in the "method based on broadcast information of the last cell."

[0127] When information indicating that the cell to which the first information is transmitted is a cell in a RAN notification area or a cell in a tracking area list is set in the second information included in the system information received by the cell that has transitioned to the idle state or the inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to the idle state or the inactive state. This processing corresponds to the case in which the PEI transmission area information of transmission area pattern 2 is broadcast in the last cell in the "method based on broadcast information of the last cell."

[0128] When the second information included in the system information received by the cell that has transitioned to the idle state or the inactive state does not include information indicating that the cell to which the first information is transmitted is the cell that has transitioned to the idle state or the inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to the idle state or the inactive state. Furthermore, when the system information includes setting information related to the first information and the second information included in the system information received by the cell that has transitioned to the idle state or the inactive state does not include information indicating that the cell to which the first information is transmitted is the cell that has transitioned to the idle state or the inactive state, the control unit 103 may monitor the downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to the idle state or the inactive state. This processing corresponds to the PEI transmission area indicating transmission area pattern 2 when PEI transmission area information is not included in the PEI setting information (or system information) in the "method based on broadcast information of the last cell."

[0129] After acquiring information about the cell from which the first information is transmitted (e.g., PEI transmission area information) from the system information received in a cell that has transitioned to an idle state or an inactive state, the control unit 103 may not acquire information about the cell from which the first information is transmitted from the system information received in the cell in which it is located until it transitions to a connected state.

[0130] When the control unit 103 receives downlink control information by monitoring the downlink control information including the first information, the control unit 103 may control monitoring of downlink control information (e.g., paging DCI, second downlink control information) including information on scheduling of a downlink shared channel that transmits a paging message at a paging occasion and / or information on a short message, based on the first information.Furthermore, when the control unit 103 does not monitor downlink control information including the first information, the control unit 103 may control monitoring of downlink control information including information on scheduling of a downlink shared channel that transmits a paging message at a paging occasion and / or information on a short message.

[0131] ≪Base station≫ FIG. 12 is a diagram showing an example of a functional block configuration of a base station according to this embodiment. As shown in FIG. 12, 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 FIG. 12 is merely an example, and any functional divisions and names of functional units may be used as long as they can perform the operations according to this embodiment. Furthermore, the first receiving unit 201 and the second receiving unit 202 may be collectively referred to as a receiving unit. Furthermore, the first transmitting unit 203 and the second transmitting unit 204 may be collectively referred to as a 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 a communication unit.

[0132] All or part of the functions realized by the first receiving unit 201, the second receiving unit 202, the first transmitting unit 203, and the second transmitting unit 204 can be realized using the communication device 13. For example, the first receiving unit 201 and the first transmitting unit 203 may be realized using the communication device 13 related to a wireless network, and the second receiving unit 202 and the second transmitting unit 204 may be realized using the communication device 13 related to a wired network. Also, all or part of the functions realized by the first receiving unit 201, the second receiving unit 202, the first transmitting unit 203, and the second transmitting unit 204, and the control unit 205, can be realized by the processor 11 executing a program stored in the storage device 12. Also, the program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-transitory storage medium. The non-transitory storage medium is not particularly limited, and may be, for example, a storage medium such as a USB memory or a CD-ROM.

[0133] The first receiving unit 201 receives a signal (for example, an UL signal and / or a sidelink signal). The first receiving unit 201 may also receive information and / or data (for example, the above-mentioned UL data) transmitted via the signal.

[0134] 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.

[0135] The first transmitter 203 transmits a signal (for example, a DL signal and / or a sidelink signal). The first transmitter 203 may also transmit information and / or data (for example, the above-mentioned DL data) transmitted via the signal.

[0136] The second transmitting unit 204 transmits signals (for example, C-plane signals and U-plane signals) to another base station 20 or the core network 30.

[0137] 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 relating to various settings to be notified to the terminal 10. Sending the information to the terminal 10 may be synonymous with "setting the information in the terminal."

[0138] The control unit 205 may control the reception of signals by the first receiving unit 201 and the second receiving unit 202. The control unit 205 may also control the transmission of signals by the first transmitting unit 203 and the second transmitting unit 204.

[0139] In this embodiment, the base station 20 may include a first transmitting unit 203 (transmitting unit) that transmits system information including second information (e.g., PEI setting information or PEI transmission area information) regarding a cell from which first information (e.g., PEI information) regarding paging at one or more paging occasions is transmitted, and a control unit 205 that controls, based on the second information, whether to transmit downlink control information (e.g., PEI DCI) including the first information to a terminal in an idle state or an inactive state.

[0140] (supplement) The PEI in the above embodiment may be referred to as a paging subgroup indicator.

[0141] The various signals, information, and parameters in the above embodiments may be signaled in any layer. That is, the various signals, information, and parameters may be replaced with signals, information, and parameters of any layer, such as an upper 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, and may be implicit (e.g., by not notifying information or by using other information).

[0142] Furthermore, the names of various signals, information, parameters, IEs, channels, time units, and frequency units in the above embodiments are merely examples and may be replaced with other names. For example, a slot may be named in any way as long as it is a time unit having a predetermined number of symbols. An RB may be named in any way as long as it is a frequency unit having a predetermined number of subcarriers. Furthermore, "first..." and "second..." merely identify multiple pieces of information or signals or functional blocks, and the order may be changed as appropriate. For example, "PEI information" and "PEI setting information" may be referred to as "second information" and "first information," respectively. Furthermore, "PEI DCI" and "paging DCI" may be referred to as "second downlink control information" and "first downlink control information," respectively. Furthermore, the PEI search space of PEI-O and the paging search space of PO may be referred to as "second search space set" and "first search space set," respectively. Furthermore, the "base station 20-1" and the "base station 20-2" may be called the "second base station" and the "first base station", respectively.

[0143] For example, in the above-described embodiment, PDSCH, PUSCH, PDCCH, PBCH, PRACH, etc. are given as examples of the physical channel for transmitting DL data, the physical channel for transmitting UL data, the physical channel for transmitting DCI, the physical channel for transmitting broadcast information, and the physical channel for transmitting RA preambles, respectively, but the names of physical channels are not limited to these as long as they have similar functions. Furthermore, these physical channels may be referred to as transport channels to which the physical channels are mapped. Furthermore, the PDSCH, PUSCH, PDCCH, PBCH, PRACH, etc. may be referred to as transport channels mapped to physical channels (for example, at least one of a Downlink Shared Channel (DL-SCH), an Uplink Shared Channel (UL-SCH), a Broadcast Channel (BCH) and a Random Access Channel (RCH)), etc. These transport channels may also be referred to as logical channels to which the transport channels are mapped. DL data and UL data are downlink and uplink data, respectively, and the data may include user data and higher layer control information (for example, RRC parameters, Medium Access Control (MAC) parameters, etc.).

[0144] Furthermore, the applications of the terminal 10 in the above embodiments (for example, RedCap, IoT, etc.) are not limited to those exemplified, and the terminal 10 may be used for any application (for example, eMBB, URLLC, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.) as long as it has similar functions. Furthermore, the format of the various information is not limited to that in the above embodiments, and may be changed as appropriate to bit representation (0 or 1), boolean value (Boolean: true or false), integer value, character, etc. Furthermore, the singular and plural in the above embodiments may be interchangeable.

[0145] The above-described embodiments are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. The flowcharts, sequences, elements included in the embodiments, and their arrangements, indexes, conditions, etc. described in the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, at least some of the configurations described in the above embodiments can be partially replaced or combined.

[0146] <Additional Notes> This embodiment can be expressed as follows.

[0147] <Appendix 1> a receiver for receiving system information including second information regarding a cell to which first information regarding paging is to be transmitted at one or more paging occasions; a control unit that, when in an idle state or an inactive state, controls whether or not to monitor downlink control information including the first information in the serving cell based on system information received in the serving cell or the cell that has transitioned to the idle state or the inactive state; A terminal comprising:

[0148] <Appendix 2> When information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state is set in the second information included in the system information received by the serving cell, the control unit When the serving cell is the same as the cell that has transitioned to an idle state or an inactive state, monitoring downlink control information including the first information in the serving cell; When the serving cell is not the same as the cell that has transitioned to the idle state or the inactive state, the serving cell does not monitor downlink control information including the first information. The device described in Appendix 1.

[0149] <Appendix 3> When information indicating that the cell to which the first information is transmitted is a cell in a RAN notification area or a cell in a tracking area list is set in the second information included in the system information received in the serving cell, the control unit monitors downlink control information including the first information in the serving cell regardless of whether the serving cell is the same as the cell that has transitioned to an idle state or an inactive state. 1. A terminal as described in Appendix 1 or 2.

[0150] <Appendix 4> When information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state is not set in the second information included in the system information received by the serving cell, the control unit monitors downlink control information including the first information in the serving cell regardless of whether the serving cell is the same as the cell that has transitioned to an idle state or an inactive state. A terminal according to any one of Supplementary Notes 1 to 3.

[0151] <Appendix 5> When information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state is set in the second information included in the system information received by the cell that has transitioned to an idle state or an inactive state, the control unit: When the serving cell is the same as the cell that has transitioned to the idle state or the inactive state, monitoring downlink control information including the first information in the serving cell; When the serving cell is not the same as the cell that has transitioned to the idle state or the inactive state, the serving cell does not monitor downlink control information including the first information. The device described in Appendix 1.

[0152] <Appendix 6> When information indicating that the cell to which the first information is transmitted is a cell in a RAN notification area or a cell in a tracking area list is set in the second information included in the system information received by the cell that has transitioned to an idle state or an inactive state, the control unit monitors downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to an idle state or an inactive state. 1. A terminal as described in Appendix 1 or 5.

[0153] <Appendix 7> When information indicating that the cell to which the first information is transmitted is a cell that has transitioned to an idle state or an inactive state is not set in the second information included in the system information received by the cell that has transitioned to an idle state or an inactive state, the control unit monitors downlink control information including the first information in the serving cell, regardless of whether the serving cell is the same as the cell that has transitioned to an idle state or an inactive state. 7. The terminal of any one of Supplementary Note 1, 5 or 6.

[0154] <Appendix 8> The control unit does not acquire information about the cell to which the first information is transmitted from the system information received in the cell that has transitioned to the idle state or the inactive state, and then does not acquire information about the cell to which the first information is transmitted from the system information received in the serving cell until the cell transitions to the connected state. A terminal according to any one of appendixes 1, 5 to 7.

[0155] <Appendix 9> a transmitter configured to transmit system information including second information regarding a cell from which first information regarding paging is transmitted on one or more paging occasions; a control unit that controls whether or not to transmit downlink control information including the first information to a terminal in an idle state or an inactive state based on the second information; A base station comprising:

[0156] <Appendix 10> receiving system information including second information regarding a cell from which first information regarding paging is to be transmitted at one or more paging occasions; When the cell is in an idle state or an inactive state, controlling whether to monitor downlink control information including the first information in the serving cell based on system information received in the serving cell or the cell that has transitioned to the idle state or the inactive state; A wireless communication method performed by a terminal, comprising:

[0157] <Appendix 11> transmitting system information including second information regarding a cell from which the first information regarding paging is transmitted on one or more paging occasions; controlling whether to transmit downlink control information including the first information to a terminal in an idle state or an inactive state based on the second information; A wireless communication method performed by a base station, comprising:

Claims

1. A receiver that receives system information including configuration information for a pre-paging indication (PEI) from a base station in a cell, and receives a radio resource control (RRC) release message from the base station in the cell; a controller configured to store the cell based on reception of the RRC release message so as to monitor a physical downlink control channel (PDCCH) for downlink control information (DCI) including a physical element information indicator (PEI) in the cell if the RRC release message is the last received RRC release message; The control unit If the PEI configuration information includes information instructing to monitor the PDCCH when the RRC release message is the last received RRC release message, control to monitor the PDCCH in the cell; If the PEI setting information does not include the information instructing to monitor the PDCCH when the RRC release message is the last received RRC release message, control is performed to monitor the PDCCH in the serving cell. Terminal.

2. The control unit controls to monitor the PDCCH at a monitoring opportunity for the PDCCH for the DCI including the PEI; The PEI indicates a subgroup of the terminals at a paging occasion; The time position of the monitoring occasion is determined based on a reference paging frame and an offset relative to the paging frame. The terminal according to claim 1 .

3. The control unit controls to monitor a PDCCH for DCI for paging at the paging occasion based on a subgroup of the terminal. The terminal according to claim 2.

4. A transmitter that transmits system information including configuration information of a pre-paging indication (PEI) to a terminal in a cell and transmits a radio resource control (RRC) release message to the terminal in the cell; a control unit configured to store the cell based on transmission of the RRC release message, so that when the RRC release message is the last RRC release message transmitted, the cell transmits downlink control information (DCI) including a PEI on a physical downlink control channel (PDCCH); The control unit When the PEI setting information includes information instructing the terminal to monitor the PDCCH when the RRC release message is the last received RRC release message, control the DCI to be transmitted on the PDCCH in the cell; If the PEI setting information does not include the information instructing the terminal to monitor the PDCCH when the RRC release message is the last received RRC release message, control is performed to transmit the DCI on the PDCCH in the cell in which the terminal is located. Base station.

5. The control unit controls the DCI to be transmitted on the PDCCH during a monitoring opportunity for the PDCCH for the DCI including the PEI; The PEI indicates a subgroup of the terminals at a paging occasion; The time position of the monitoring occasion is determined based on a reference paging frame and an offset relative to the paging frame. The base station of claim 4.

6. The control unit controls to transmit DCI for paging on a PDCCH at the paging occasion based on a subgroup of the terminal. The base station of claim 5.

7. A step of receiving system information including configuration information of a pre-paging indication (PEI) from a base station in a cell; receiving a radio resource control (RRC) release message from the base station in the cell; based on receiving the RRC release message, storing the cell to monitor a physical downlink control channel (PDCCH) for downlink control information (DCI) including a physical downlink information indicator (PEI) at the cell if the RRC release message is the last received RRC release message; If the PEI configuration information includes information instructing to monitor the PDCCH when the RRC release message is the last received RRC release message, controlling to monitor the PDCCH in the cell; If the PEI setting information does not include the information instructing to monitor the PDCCH when the RRC release message is the last received RRC release message, controlling to monitor the PDCCH in a serving cell. Wireless communication method.

8. The method of claim 7, further comprising: controlling to monitor the PDCCH at a monitoring opportunity for the PDCCH for the DCI including the PEI; The PEI indicates a subgroup of the terminals at a paging occasion; The time position of the monitoring occasion is determined based on a reference paging frame and an offset relative to the paging frame. The wireless communication method according to claim 7.

9. The method of claim 8, further comprising: controlling, based on a subgroup of the terminal, to monitor a PDCCH for DCI for paging at the paging occasion. The wireless communication method according to claim 8.

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