Terminal, base station, core network device, and wireless communication method

Abstract

Provided is a terminal having: a transmission unit for transmitting a setting request to request setting of an eDRX setting value intended for an RRC inactive state, the eDRX setting value including information for designating the number of candidates for a starting position of a reception period in a prescribed H-SFN; a reception unit for receiving second setting information including an eDRX value intended for an RRC inactive state, the eDRX value including information for designating the number of candidates for a starting position of a reception period in a prescribed H-SFN and being set in accordance with the setting request transmitted from the transmission unit; and a control unit for identifying the start position of the reception period in the prescribed H-SFN in an RRC inactive state in accordance with the second setting information received by the reception unit and performing control so as to execute eDRX.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2021-162295 filed on September 30, 2021, and claims the benefit of priority thereto, the entire contents of which are incorporated herein by reference. [Technical field]

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

[0003] The Third Generation Partnership Project (3GPP), an international standardization organization, has finalized Release 15, which specifies 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 (Non-Patent Document 1). Furthermore, in LTE (Long Term Evolution), taking into consideration the existence of terminals with further power consumption restrictions, such as IoT (Internet of Things) devices, a technology called eDRX (extended Discontinuous Reception) has been introduced that reduces power consumption by limiting the period during which wireless signals can be received (Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V15.11.0 (2020-09) [Non-Patent Document 2] 3GPP TS 36.300 V15.12.0 (2020-12) Summary of the Invention

[0005] Currently, 3GPP has started to study functions for new terminals for IoT that use NR for radio access. The functions under study include the above-mentioned eDRX. On the other hand, 3GPP specifies that a UE has multiple RRC states. Further study is required on a mechanism for reducing power consumption in at least one of these multiple UE states.

[0006] One of the objectives of the present disclosure is to provide a terminal, a base station, a core network device, and a wireless communication method that enable eDRX to be applied to a terminal in an RRC inactive state.

[0007] A terminal according to one embodiment of the present disclosure has a transmitter that transmits a setting request to request setting of an eDRX setting value for an RRC inactive state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN; a receiver that receives second setting information including an eDRX setting value for an RRC inactive state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN, which is set in response to the setting request transmitted from the transmitter; and a control unit that controls, in the RRC inactive state, to perform eDRX by matching the number of start positions of a reception period in a specified H-SFN with the number specified by the second setting information received by the receiver.

[0008] According to the present disclosure, it is possible to provide a terminal, a base station, a core network device, and a wireless communication method that enable eDRX to be applied to a terminal in an RRC inactive state. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of an overview of a wireless communication system according to this embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a state transition of a terminal. [Diagram 3] FIG. 3 is a diagram for explaining the DRX operation during paging. [Figure 4] FIG. 4 is a diagram for explaining eDRX operation during paging. [Diagram 5] FIG. 5 is a diagram illustrating an example of a processing procedure in which eDRX parameters for an idle state and eDRX parameters for an inactive state are managed by a core network. [Figure 6] FIG. 6 is a diagram illustrating an example of a processing procedure in which eDRX parameters for an idle state are managed by a core network and eDRX parameters for an inactive state are managed by a base station. [Figure 7] FIG. 7 is a diagram illustrating an example of a processing procedure in which eDRX parameters for an idle state are managed by a core network and eDRX parameters for an inactive state are managed by a base station. [Figure 8] FIG. 8 is a diagram illustrating an example of a paging procedure when a terminal is in an idle state or an inactive state. [Figure 9] FIG. 9 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 10] FIG. 10 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 11] FIG. 11 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 12] FIG. 12 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 13] FIG. 13 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 14] FIG. 14 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 15] FIG. 15 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 16] FIG. 16 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 17]FIG. 17 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 18] FIG. 18 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 19] FIG. 19 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 20] FIG. 20 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 21] FIG. 21 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 22] FIG. 22 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 23] FIG. 23 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 24] FIG. 24 is a diagram showing an example of specification changes in the 3GPP specifications. [Diagram 25] FIG. 25 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 26] FIG. 26 is a diagram illustrating an example of a hardware configuration of each device in a wireless communication system. [Figure 27] FIG. 27 is a diagram illustrating an example of a functional configuration of a terminal. [Figure 28] FIG. 28 is a diagram illustrating an example of a functional configuration of a base station. [Figure 29] FIG. 29 is a diagram illustrating an example of a functional configuration of a core network. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

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

[0012] The wireless communication system 1 is a system that communicates in compliance with a radio access technology (RAT) defined by 3GPP. The wireless access technology that the wireless communication system 1 complies with is assumed to be, for example, NR, but is not limited thereto, and various RATs such as LTE, LTE-Advanced, or RATs of the sixth generation or later can be used. Note that the wireless communication system 1 may be in a form that performs communication in compliance with a radio access technology defined by a standardization organization other than 3GPP.

[0013] The terminal 10 is a device corresponding to a terminal (for example, User Equipment (UE)) specified 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 be called a user equipment (User Equipment: UE), a mobile station (Mobile Station: MS), a terminal (User Terminal), a radio apparatus, a subscriber terminal, an access terminal, or the like. The terminal 10 may be a mobile type or a fixed type. The terminal 10 is configured to be able to communicate using, for example, NR as a RAT. Note that the terminal 10 is not limited to a terminal specified in the 3GPP specifications, and may be a terminal conforming to a standard specified by another standardization organization. Furthermore, the terminal 10 does not have to be a terminal conforming to a standard.

[0014] Here, in NR Release 17, support for functions for terminals with lower performance and price range than terminals for enhanced Mobile Broadband (eMBB) and Ultra-reliable and Low Latency Communications (URLLC) introduced in Release 15 or 16 is being considered. Such terminals are also called reduced capability (RedCap) terminals or devices, and are expected to be used, for example, in industrial wireless sensors, video surveillance cameras, wearable devices, etc.

[0015] The RedCap terminal is assumed to have higher performance than a terminal for low power wide area communication (LPWA), and the carrier used by the RedCap terminal may have a bandwidth of, for example, 20 MHz, 50 MHz, or 100 MHz. In addition, LPWA includes, for example, Category 0, Category 1, Long Term Evolution for Machine-type-communication (LTE-M) and Narrow Band IoT (NB-IoT) that operate on a RAT of the LTE system. The maximum bandwidth of Category 0 is 20 MHz, the maximum bandwidth of Category 1 is 20 MHz, the maximum bandwidth of LTE-M is 1.4 MHz (6 RB), and the maximum bandwidth of NB-IoT is 180 kHz (1 RB). In this way, the RedCap terminal is assumed to be used as a middle-range terminal between eMBB, URLLC, and LPWA. The terminal 10 according to this embodiment includes a RedCap terminal and a terminal for LPWA.

[0016] The base station 20 is a device equivalent to a base station (for example, a gNodeB (gNB) or eNB) defined in the 3GPP specifications. The base station 20 forms one or more cells C and communicates with the terminal 10 using the cell C. The cell C may be interchangeably referred to as a serving cell, a carrier, a component carrier (CC), or the like. The base station 20 may be called a gNodeB (gNB), en-gNB, a Next Generation-Radio Access Network (NG-RAN) node, an eNB, an ng-eNB, a low-power node, a Central Unit (CU), a Distributed Unit (DU), a gNB-DU, a Remote Radio Head (RRH), an Integrated Access and Backhaul / Backhauling (IAB) node, or the like. The base station 20 is not limited to one node, and may be configured of multiple nodes (for example, a combination of a lower node such as a DU and an upper node such as a CU). The terminal 10 is not limited to a base station defined in the 3GPP specifications, and may be a terminal conforming to a standard defined by another standard development organization. Also, the terminal 10 does not have to be a base station conforming to a standard.

[0017] The core network 30 is, for example, a core network compatible with NR (5G Core Network: 5GC), but is not limited to this. An apparatus on the core network 30 (hereinafter also referred to as a "core network apparatus") performs mobility management such as paging and location registration of the terminal 10. The core network apparatus may be connected to the base station 20 via a predetermined interface (for example, an S1 or NG interface). The base station 20 and / or the core network 30 may be referred to as a "network."

[0018] The core network device includes at least one of a plurality of functions such as an AMF (Access and Mobility Management Function) that manages information related to access and mobility management, an SMF (Session Management Function) that performs session management, a User Plane Function (UPF) that controls U-plane transmission, and an NSSF (Network Slice Selection Function) that manages network slices. Each of these functions is implemented in one or more physical or logical devices. Hereinafter, unless otherwise specified, when referring to the core network device itself, it is also denoted as the core network 30.

[0019] In the wireless communication system 1, the terminal 10 receives a downlink (DL) signal from the base station 20 and / or transmits an uplink (UL) signal. One or more carriers may be configured for the terminal 10. The bandwidth of each carrier is, for example, 5 MHz to 400 MHz. One or more Bandwidth Parts (BWPs) may be configured for one carrier. One BWP has at least a part of the bandwidth of the carrier.

[0020] <UE state> Next, the RRC (Radio Resource Control) state of the terminal 10 will be described. The RRC state of the terminal 10 includes an RRC idle state (hereinafter referred to as the "idle state"), an RRC inactive state (hereinafter referred to as the "inactive state"), and an RRC connected state (hereinafter referred to as the "connected state").

[0021] FIG. 2 is a diagram showing an example of the state transition of the terminal 10. In FIG. 2, the idle state is a state in which the 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.

[0022] The terminal 10 in the idle state camps on a cell C selected by cell selection and / or cell reselection (hereinafter referred to as "cell selection / reselection"), and receives system information broadcast in the cell C. When an RRC connection is established, the terminal 10 in the idle state transitions to a connected state.

[0023] The inactive state is a state in which an RRC connection is established but suspended, and is also called RRC_INACTIVE, inactive mode, RRC inactive mode, etc. The terminal 10 in the inactive state camps on a cell C selected by cell selection / reselection, and receives system information broadcast in the cell C. The inactive state, like the idle state, allows the terminal 10 to save power, but unlike the idle state, the terminal 10, the base station 20, and the core network 30 hold the context (RRC context and / or NAS context) of the terminal 10.

[0024] In addition, in NR, a RAN Notification Area (RNA) is newly defined, which is an area obtained by subdividing a Tracking Area (TA), and the base station 20 manages the RAN notification area in which the terminals 10 in the connected state and the inactive state exist. In addition, in NR, a technology called "RAN paging" is introduced, which is used when calling a terminal 10 in the inactive state and performs paging processing in units of RAN notification areas. In RAN paging, a paging signal is transmitted simultaneously from a plurality of base stations 20 constituting a RAN notification area in which the terminals 10 in the inactive state exist. The terminals 10 in the inactive state that receive the paging signal resume the RRC connection and transition to the connected state.

[0025] The connected state is the state in which the above RRC connection is established, and is also called RRC_CONNECTED, connected mode, RRC connected mode, etc. The terminal 10 in the connected state monitors the PDCCH (Physical Downlink Control Channel) and controls the reception of the PDSCH (Physical Downlink Shared Channel) based on the detected DCI (Downlink Control Information). When the RRC connection of the terminal 10 in the connected state is released, it transitions to the idle state, and when the RRC connection is suspended, it transitions to the inactive state.

[0026] <eDRX technology> Here, the eDRX (extended DRX) technology will be described. A subframe represents a time length of 1 ms, a radio frame represents a time length of 10 ms, and a hyperframe represents a time length of 10.24 seconds. The position of the radio frame is represented by the SFN (System Frame Number) from 0 to 1023. Also, in order to manage a time longer than 1024 radio frames, a hyperframe with a length of SFN from 0 to 1023 (that is, 10.24 seconds) is defined. The hyperframe is represented by the H-SFN (Hyper-SFN) from 0 to 1023 numbers. The H-SFN is also called the HFN (hyper frame number).

[0027] FIG. 3 is a diagram for explaining DRX (Discontinuous reception) operation during paging. As shown in FIG. 3, a terminal 10 in an idle state receives a paging signal by monitoring downlink control channel candidates (PDCCH candidates) in a period called a PO (Paging Occasion). While the terminal 10 is operating according to the DRX setting, the base station 20 transmits a paging signal in the PO period and does not transmit a paging signal in other periods. A terminal 10 that receives a paging signal within a PO period establishes communication with the base station 20 and transitions to a connected state. One PO exists for each DRX cycle. The maximum length of a DRX cycle is 2.56 seconds.

[0028] FIG. 4 is a diagram for explaining eDRX operation during paging. As shown in FIG. 4, a terminal 10 in an idle state receives a paging signal by monitoring downlink control channel candidates in a PO period that exists within a period called a PTW (Paging Time Window). One PTW is set in a hyperframe called a PH (Paging Hyperframe). One PH exists for each eDRX cycle. In the case of a terminal 10 that is an NB-IoT, the eDRX cycle may be set to a maximum of 2.91 hours (i.e., 1024 hyperframes), and in the case of a terminal 10 other than an NB-IoT, the eDRX cycle may be set to a maximum of about 44 minutes (i.e., 256 hyperframes).

[0029] While the terminal 10 is operating according to the eDRX setting, the base station 20 transmits a paging signal during the PTW period and the PO period, and does not transmit a paging signal during other periods. The terminal 10 that receives the paging signal establishes communication with the base station 20 and transitions to a connected state.

[0030] Here, PH may be H-SFN that satisfies the following formula 1.

[0031] (Formula 1) H-SFN mod TeDRX,H = (UE_ID_H mod TeDRX,H) "TeDRX,H" indicates an eDRX cycle and is set to an integer multiple of the length of a hyperframe. UE_ID_H is the most significant 10 or 12 bits of a hashed ID determined based on S-TMSI (SAE Temporary Mobile Subscriber Identity) or 5G-S-TMIS (5G S-Temporary Mobile Subscriber Identity).

[0032] The SFN, which is the start position (PTW_start) (start timing) of the PTW, may be expressed by the following Equation 2 and Equation 3.

[0033] (Formula 2) SFN = 256 * ieDRX (Formula 3) ieDRX=floor(UE_ID_H / TeDRX,H) mod 4 The SFN, which is the end position (PTW_end) (end timing) of the PTW, may be expressed by the following Equation 4.

[0034] (Formula 4) SFN = (PTW_start+L*100-1) mod 1024 L is the PTW time length (Paging Time Window length). Parameters that determine eDRX operation, such as the eDRX cycle and the PTW time length (hereinafter referred to as "eDRX parameters"), are set in the terminal 10 by a message from a higher layer (NAS (Non Access Stratum)). Hereinafter, "PTW" means the PTW time length unless otherwise specified.

[0035] Furthermore, the terminal 10, base station 20, and core network 30 according to this embodiment may include predetermined information related to setting the start position of the PTW in the eDRX parameters, thereby making it possible to flexibly set the start position of the PTW. For example, the predetermined information related to setting the start position of the PTW may include information indicating the number of start positions of the PTW in the PH (the number of SFNs that can be set as the start SFN of the PTW), and the start position of the PTW may be determined by inputting the information indicating the number of start positions of the PTW in the PH into a predetermined formula. The predetermined formula may be Formula 5 and Formula 6 shown below. Furthermore, the end position of the PTW may be determined according to Formula 4, similar to LTE.

[0036] (Formula 5) SFN = (1024 div NPTW)*ieDRX (Equation 6) ieDRX=floor(UE_ID_H / TeDRX,H) mod NPTW In Equations 5 and 6, NPTW is information indicating the number of PTW start positions in the PH. In other words, NPTW is information for specifying the number of candidates for the PTW start position in the PH, and can be said to be a parameter for making the number of candidates for the PTW start position in the PH variable. NPTW may be information for specifying the number of PTW start positions in the PH. For example, when NPTW=8, the possible values ​​of ieDRX are 0 to 7, so the start position of the PTW is one of the eight values ​​of SFN=0, 128, 256, 384, 512, 640, 768, and 896. Note that when NPTW=4, Equations 5 and 6 are the same as Equations 2 and 3, respectively. In other words, by using Equations 5 and 6, it becomes possible to set the start position of the PTW more flexibly than in LTE.

[0037] When determining the start position of the PTW according to Formulas 5 and 6 and determining the end position of the PTW according to Formula 4, the eDRX parameters include the eDRX cycle (TeDRX,H in Formula 6), the time length of the PTW (L in Formula 4), and the number of the start position of the PTW in PH (NPTW in Formula 5).

[0038] Also, in the wireless communication system 1 according to the present embodiment, the predetermined information regarding the setting of the start position of the PTW may include information specifying a radio frame indicating the start position of the PTW. For example, the information specifying a radio frame indicating the start position of the PTW may be information specifying a specific radio frame number such as SFN = 0, SFN = 64, etc. Further, the eDRX parameters may include information specifying a radio frame indicating the end position of the PTW (for example, SFN = 64, SFN = 128, etc.). Thereby, it becomes possible to flexibly set the end position of the PTW. In this case, the eDRX parameters include the eDRX cycle, information specifying a radio frame indicating the start position of the PTW, and information specifying a radio frame indicating the end position of the PTW.

[0039] <Problems in Implementing eDRX in NR> Currently, in 3GPP, studies are underway to implement eDRX in NR. However, the processing procedures necessary for applying eDRX to the idle terminal 10, such as the setting of the eDRX parameters, are not defined in the current 3GPP (the first problem). Similarly, the processing procedures necessary for applying eDRX to the non-active terminal 10 are not defined in the current 3GPP (the second problem).

[0040] In this embodiment, in order to solve the first problem, eDRX parameters to be applied to the terminal 10 in an idle state can be set in the terminal 10 and the network so that the terminal 10 performs eDRX operation in an idle state. Also, in this embodiment, in order to solve the second problem, eDRX parameters to be applied to the terminal 10 in an inactive state can be set in the terminal 10 and the network so that the terminal 10 performs eDRX operation in an inactive state.

[0041] In the following description, "eDRX parameters" may mean only parameters that determine eDRX operation, such as the eDRX cycle, the time length of the PTW, and the number of start positions of the PTW in the PH, or may mean parameters that determine DRX operation, such as the setting of the DRX cycle and the PO position, in addition to parameters that determine eDRX operation. A message that transmits "eDRX parameters" has a 4-octet area, and the "eDRX parameters" may be stored in a 2-octet area of ​​the 4 octets. Furthermore, "eDRX parameters" for the inactive state mean eDRX parameters applied to a terminal 10 in the inactive state. Furthermore, "eDRX parameters" for the idle state mean eDRX parameters applied to a terminal 10 in the idle state.

[0042] <Procedure for achieving eDRX in idle or inactive state> When implementing eDRX in an idle or inactive state, there are two possible methods for managing the “eDRX parameters” for the idle state and the “eDRX parameters” for the inactive state: managing them in the core network 30 or managing them in the base station 20.

[0043] 5 is a diagram showing an example of a processing procedure when "eDRX parameters" for an idle state and "eDRX parameters" for an inactive state are managed by the core network 30. Note that the core network 30 is assumed to be, for example, an AMF, but is not limited thereto.

[0044] A terminal 10 that desires to enable eDRX transmits a registration request message including "eDRX parameters" indicating the eDRX operation that is desired (requested) to be set to the core network 30 (S100). For example, a terminal 10 that desires eDRX operation in which the eDRX cycle is 2 hyperframes, the PTW is 1.28 seconds, and the number of PTW start positions is 8 transmits a registration request to the core network 30 including eDRX parameters indicating that the eDRX cycle is 2 hyperframes, the PTW is 1.28 seconds, and the number of PTW start positions is 8.

[0045] Here, the terminal 10 may include in the registration request message an "eDRX parameter" indicating an eDRX operation for an idle state and an "eDRX parameter" indicating an eDRX operation for an inactive state, in a distinguished manner. For example, it is assumed that the terminal 10 desires (requests) an eDRX operation in which the eDRX cycle is 10 hyperframes, the PTW is 2 seconds, and the number of PTW start positions is 8 in the idle state, and desires (requests) an eDRX operation in which the eDRX cycle is 4 hyperframes, the PTW is 1 second, and the number of PTW start positions is 4 in the inactive state. In this case, the terminal 10 may transmit to the core network 30 “eDRX parameters” for the idle state indicating that the eDRX cycle in the idle state is 10 hyperframes, the PTW is 2 seconds, and the number of PTW start positions is 8, and “eDRX parameters” for the inactive state indicating that the eDRX cycle in the inactive state is 4 hyperframes, the PTW is 1 second, and the number of PTW start positions is 4.

[0046] Furthermore, when it is desired (required) that the "eDRX parameters" for the inactive state may be the same as the "eDRX parameters" for the idle state, the terminal 10 may explicitly or implicitly include information indicating that the eDRX parameters for the inactive state are the same value as the eDRX parameters for the idle state in the registration request message. For example, when the registration request message includes the eDRX parameters for the idle state but does not include the eDRX parameters for the inactive state (for example, when nothing is set in the eDRX parameters for the inactive state, or when a predetermined character string or a predetermined numerical value such as "absent" or "NULL" is set in the eDRX parameters), it may be implicitly indicated that the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state. Note that the information indicating that the eDRX parameters for the inactive state are the same value as the eDRX parameters for the idle state may be set for each eDRX parameter.

[0047] Next, the core network 30 determines (sets) "eDRX parameters" for the idle state and "eDRX parameters" for the inactive state based on the registration request received from the terminal 10 (S101). The core network 30 determines "eDRX parameters" for the idle state and "eDRX parameters" for the inactive state to be set in the terminal 10, taking into consideration, for example, the eDRX parameters received from the terminal 10, the network load, the attributes of the terminal 10, and / or the capabilities of the terminal 10. The core network 30 may determine the "eDRX parameters" to be set in the terminal 10 to be the same value as the "eDRX parameters" included in the registration request, or may determine the "eDRX parameters" to be different from the "eDRX parameters" included in the registration request. The core network 30 may determine the "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state so that the PTW start position in the idle state and the PTW start position in the inactive state are the same.

[0048] Next, the core network 30 transmits a registration response (Registration Accept) message including the determined "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state to the terminal 10 in order to set the determined "eDRX parameters" in the terminal 10 (S102). When the determined "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state are the same, the core network 30 may explicitly or implicitly include information indicating that the "eDRX parameters" for the inactive state are the same value as the "eDRX parameters" for the idle state in the registration response message. For example, when the registration response message includes the "eDRX parameters" for the idle state but does not include the "eDRX parameters" for the inactive state (for example, when the eDRX parameters are "absent"), the "eDRX parameters" for the inactive state may be implicitly indicated to be the same as the "eDRX parameters" for the idle state.

[0049] The terminal 10 sets the "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state, which are included in the registration response message (stores the "eDRX parameters" in the storage device 12) (S103). Note that, when the registration response message explicitly or implicitly includes information indicating that the "eDRX parameters" for the inactive state have the same value as the "eDRX parameters" for the idle state, the terminal 10 may recognize that the "eDRX parameters" for the inactive state have the same value as the "eDRX parameters" for the idle state. In this case, the terminal 10 may set the "eDRX parameters" for the inactive state to the same value as the "eDRX parameters" for the idle state. Note that the registration request message and the registration acceptance message described above are merely examples, and any NAS message may be used.

[0050] When the terminal 10 is in an idle state, the terminal 10 monitors control channel candidates in the paging search space at a PTW in the PH indicated by the "eDRX parameters" for the idle state set. When the base station 20 transmits a paging message to the terminal 10 in the idle state, the base station 20 transmits DCI in the paging search space at a PTW in the PH indicated by the "eDRX parameters" for the idle state set in the terminal 10. When the terminal 10 is in an inactive state, the terminal 10 monitors control channel candidates in the paging search space at a PTW in the PH indicated by the eDRX parameters for the inactive state set. When the base station 20 transmits a paging message to the terminal 10 in an inactive state, the base station 20 transmits DCI in the paging search space at a PTW in the PH indicated by the "eDRX parameters" for the inactive state set in the terminal 10.

[0051] 6 is a diagram showing an example of a processing procedure in which "eDRX parameters" for an idle state are managed by the core network 30, and "eDRX parameters" for an inactive state are managed by the base station 20. Note that the base station 20-A is a base station 20 (serving base station) that communicates with the terminal 10, and the base station 20-B is a base station 20 adjacent to the base station 20-A.

[0052] A terminal 10 that wishes to enable eDRX transmits a registration request message including "eDRX parameters" indicating an eDRX operation that is desired (requested) to be set to the core network 30 (S200). Here, the terminal 10 may distinguish between "eDRX parameters" for an idle state that is desired (requested) to be set and "eDRX parameters" for an inactive state that is desired (requested) to be set and include these in the registration request message.

[0053] Furthermore, when it is desired (requested) that the "eDRX parameters" for the inactive state may be the same as the "eDRX parameters" for the idle state, the terminal 10 may explicitly or implicitly include, in the registration request message, information indicating that the "eDRX parameters" for the inactive state are the same as the "eDRX parameters" for the idle state. For example, when the registration request message contains information indicating that the "eDRX parameters" for the inactive state are requested (for example, the name of an information element (Information Element) that stores the eDRX parameters) but does not contain specific eDRX parameters (i.e., when the eDRX parameters are "absent"), it may be implicitly indicated that the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state.

[0054] Next, the core network 30 determines (sets) "eDRX parameters" for the idle state based on the registration request received from the terminal 10 (S201). The core network 30 may determine the "eDRX parameters" for the idle state by referring to the "eDRX parameters" for the inactive state received from the terminal 10. For example, the core network 30 may determine the "eDRX parameters" for the idle state so that the PTW start position of the idle state is the same as the PTW start position calculated by the "eDRX parameters" for the inactive state that the terminal 10 desires (requests) to be set. In addition, the core network 30 transmits a message including the determined "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state that indicate the eDRX operation that the terminal 10 desires (requests) to be set, transmitted from the terminal 10 to the core network 30, to the base station 20-A (S202).

[0055] Specifically, the core network 30 transmits an initial context setup request message to the base station 20-A to notify the base station 20-A of information necessary for the base station 20 to communicate with the terminal 10. Here, the core network 30 notifies the base station 20 of the "eDRX parameters" for the idle state determined by the core network 30 and the "eDRX parameters" for the inactive state indicating the eDRX operation that the terminal 10 desires (requests) to be set. For this purpose, the core network 30 transmits the eDRX parameters for the idle state and the "eDRX parameters" for the inactive state in the initial context setup request. Note that the eDRX parameters for the idle state and the "eDRX parameters" for the inactive state are included in the initial context setup request. They may be part of Core Network Assistance Information for RRC INACTIVE. Note that the message transmitted and received between the base station 20 and the core network 30 is called an N2 message. The N2 message includes an initial context setup request message, a UE context modification request message, a handover request message, a path switch request acknowledge message, and the like. The core network 30 may transmit these N2 messages to the base station 20-A, including eDRX parameters for the idle state and “eDRX parameters” for the inactive state. By receiving an N2 message including eDRX parameters for the idle state, the base station 20-A can recognize the eDRX parameters for the idle state set in the terminal 10. Also, by receiving an N2 message including eDRX parameters for the inactive state, the base station 20-A can recognize the eDRX parameters for the inactive state that the terminal 10 desires (requests) to be set.

[0056] Next, the base station 20-A determines eDRX parameters for the inactive state based on the message received from the core network 30 (S203). In this case, the base station 20-A may determine the "eDRX parameters" for the inactive state by referring to the "eDRX parameters" for the idle state received from the core network 30. For example, the base station 20-A may determine the "eDRX parameters" for the inactive state so that the PTW start position in the inactive state is the same as the PTW start position calculated by the "eDRX parameters" for the idle state received from the core network 30. In addition, the base station 20-A transmits a message including the determined "eDRX parameters" for the inactive state to the core network 30 (S204).

[0057] Specifically, the base station 20-A transmits an initial context setup response message, which is a response message to the initial context setup request, to the core network 30. Here, in order to notify the core network 30 of the "eDRX parameters" for the inactive state determined by the base station 20-A, the base station 20-A transmits the eDRX parameters for the inactive state by including them in the initial context setup response. Note that the eDRX parameters for the inactive state may be part of the Core Network Assistance Information for RRC INACTIVE included in the initial context setup response. In addition to the initial context setup response message, the N2 message also includes a UE context modification response message, a Handover request acknowledge message, a Path switch request message, and the like. The base station 20-A may transmit these N2 messages to the core network 30 by including the eDRX parameters for the inactive state.

[0058] Next, when the PTW start position calculated from the "eDRX parameters" for the idle state determined in the previous step S201 differs from the PTW start position calculated from the "eDRX parameters" for the inactive state included in the message received from the base station 20-A, the core network 30 may change the "eDRX parameters" for the idle state so that the PTW start position in the idle state becomes the same as the PTW start position calculated from the "eDRX parameters" for the inactive state. For example, the core network 30 may change the "eDRX parameters" for the idle state so that they match the "eDRX parameters" for the inactive state (S205). In addition, for example, if the number of PTW start positions in a PH specified by the "eDRX parameters" for the idle state is made equal to the number of PTW start positions in a PH specified by the "eDRX parameters" for the inactive state, the core network 30 may change the "eDRX parameters" for the idle state so that the number of PTW start positions in a PH specified by the "eDRX parameters" for the idle state becomes the same as the number of PTW start positions in a PH specified by the "eDRX parameters" for the inactive state.

[0059] Next, the core network 30 transmits a registration response (Registration Accept) message including the determined "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state to the terminal 10 in order to set the determined "eDRX parameters" in the terminal 10 (S206). When the "eDRX parameters" for the inactive state are the same as the "eDRX parameters" for the idle state, the core network 30 may explicitly or implicitly include information indicating that the "eDRX parameters" for the inactive state are the same as the "eDRX parameters" for the idle state in the registration response message. For example, when the registration response message includes information indicating the presence of the "eDRX parameters" for the inactive state (e.g., the name of an information element (Information Element) that stores the eDRX parameters) but does not include specific eDRX parameters (i.e., when the eDRX parameters are "absent"), it may implicitly indicate that the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state.

[0060] The terminal 10 sets the "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state, which are included in the registration response message (stores the "eDRX parameters" in the storage device 12) (S207).

[0061] Thereafter, the terminal 10 monitors control channel candidates in the paging search space at a PTW in a PH indicated by the set eDRX parameters for an idle state or eDRX parameters for an inactive state, as in the description of Fig. 5. Furthermore, when transmitting a paging message, the base station 20-A transmits DCI in the paging search space at a PTW in a PH indicated by the eDRX parameters for an idle state or eDRX parameters for an inactive state.

[0062] FIG. 7 is a diagram showing an example of a processing procedure in which the "eDRX parameters" for the idle state are managed by the core network 30, and the "eDRX parameters" for the inactive state are managed by the base station 20-A.

[0063] A terminal 10 that wishes to enable eDRX transmits a registration request message including "eDRX parameters" indicating an eDRX operation that is desired (requested) to be set to the core network 30 (S300). Here, the terminal 10 may include, in the registration request message, "eDRX parameters" for an idle state that is desired (requested) to be set.

[0064] Next, the core network 30 determines "eDRX parameters" for the idle state based on the registration request received from the terminal 10 (S301).

[0065] Next, the core network 30 transmits a registration accept message including the determined "eDRX parameters" for the idle state to the terminal 10 in order to set the determined "eDRX parameters" in the terminal 10 (S302).

[0066] The terminal 10 sets the "eDRX parameters" for the idle state included in the registration response message (stores the eDRX parameters in the storage device 12) (S303).

[0067] Furthermore, the core network 30 transmits a message (N2 message) including the "eDRX parameters" for the idle state determined in the previous step S301 to the base station 20-A (S304).

[0068] Specifically, the core network 30 transmits an initial context setup request message to the base station 20-A in order to notify the base station 20-A of information necessary for the base station 20 to communicate with the terminal 10. Here, the core network 30 transmits the eDRX parameters for the idle state included in the initial context setup request in order to notify the base station 20 of the "eDRX parameters" for the idle state determined by the core network 30. Note that the eDRX parameters for the idle state may be part of the core network assist information regarding RRC inactive included in the initial context setup request. The N2 message transmitted in step S304 includes, in addition to the initial context setup request message, a UE context modification request message, a handover request message, a path switch request acknowledge message, and the like. The core network 30 may transmit these N2 messages including the eDRX parameters for the idle state to the base station 20-A. By receiving the N2 message including the eDRX parameters for the idle state, the base station 20-A can recognize the eDRX parameters for the idle state that are set in the terminal 10.

[0069] Then, communication is started between the terminal 10 and the base station 20, and an RRC message is transmitted and received as necessary. Examples of the RRC message transmitted from the terminal 10 to the base station 20 include an RRC setup request (RRCSetupRequest) message, an RRC setup complete (RRCSetupComplete) message, an RRC reconfiguration complete (RRCReconfigurationComplete) message, an RRC reestablishment request (RRCReestablishmentRequest) message, an RRC reestablishment complete (RRCReestablishmentComplete) message, an RRC resume request (RRCResumeRequest / RRCResumeRequest1) message, an RRC resume complete (RRCResume Complete) message, and the like.

[0070] Here, the terminal 10 desiring to enable eDRX transmits an RRC message including "eDRX parameters" indicating eDRX operation for a deactivated state that is desired (requested) to be set to the base station 20 (S305). The terminal 10 may transmit the eDRX parameters to the base station 20 by including them in an RRC setup request message or an RRC setup complete message. Alternatively, the terminal 10 may transmit the eDRX parameters to the base station 20 by including them in an RRC reconfiguration complete message, an RRC re-establishment request message, an RRC re-establishment complete message, an RRC restart request message, an RRC restart complete message, or the like.

[0071] When the "eDRX parameters" for the inactive state are included in the RRC setup complete message, the terminal 10 may include the "eDRX parameters" for the idle state in a Registration Request message included in the RRC setup complete message. That is, the processing procedure of step S300 may be included in the processing procedure of step S305 in Fig. 7. Since it becomes possible to transmit the "eDRX parameters" for the idle state and the "eDRX parameters" for the inactive state at the same timing, it is possible to simplify the processing logic of the terminal 10.

[0072] For example, assume that the terminal 10 desires eDRX operation in an inactive state in which the eDRX cycle is 2 hyperframes, the PTW is 1 second, and the number of PTW start positions is 8. In this case, the terminal 10 may transmit to the base station 20 “eDRX parameters” for the inactive state indicating that the eDRX cycle in the inactive state is 2 hyperframes, the PTW is 2 seconds, and the number of PTW start positions is 8.

[0073] Furthermore, when it is desired that the "eDRX parameters" for the inactive state may be the same as the "eDRX parameters" for the idle state, the terminal 10 may explicitly or implicitly include, in the RRC message, information indicating that the "eDRX parameters" for the inactive state are the same as the "eDRX parameters" for the idle state. For example, when the RRC setup complete message contains information indicating that the "eDRX parameters" for the inactive state are requested (for example, the name of an information element (information element) that stores the eDRX parameters) but does not contain specific eDRX parameters (i.e., when the eDRX parameters are "absent"), it may be implicitly indicated that the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state.

[0074] Next, the base station 20 determines the "eDRX parameters" for the inactive state to be set in the terminal 10 based on the "eDRX parameters" for the inactive state received from the terminal 10 (S306). The base station 20 determines the "eDRX parameters" for the inactive state to be set in the terminal 10, for example, taking into consideration the "eDRX parameters" received from the terminal 10, the load of the wireless network, the attributes of the terminal 10 and / or the capabilities of the terminal 10. The base station 20 may determine the "eDRX parameters" to be set in the terminal 10 to be the same value as the "eDRX parameters" desired by the terminal 10, or may determine a value different from the "eDRX parameters" desired by the terminal 10. The base station 20-A may also determine the "eDRX parameters" for the inactive state by referring to the "eDRX parameters" for the idle state received from the core network 30 in step S304. For example, the base station 20-A may determine the “eDRX parameters” for the inactive state so that the PTW start position for the inactive state is identical to the PTW start position calculated using the “eDRX parameters” for the idle state received from the core network 30.

[0075] Next, when instructing the terminal 10 to transition to the inactive state, the base station 20 transmits an RRC release message including the determined "eDRX parameters" for the inactive state to the terminal 10 (S307). Note that, when the determined "eDRX parameters" for the idle state (the "eDRX parameters" for the idle state notified from the core network 30 in step S304) are the same as the "eDRX parameters" for the inactive state, the base station 20 may explicitly or implicitly include information indicating that the eDRX parameters for the inactive state are the same value as the eDRX parameters for the idle state in the RRC release message. For example, when the RRC release message contains information indicating that the "eDRX parameters" for the inactive state are set (for example, the name of an information element that stores the eDRX parameters) but does not contain a specific eDRX parameter (i.e., when the eDRX parameter is "absent"), it may implicitly indicate that the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state.

[0076] The terminal 10 sets the eDRX parameters for the deactive state included in the RRC release message (stores the eDRX parameters in the storage device 12) (S308). Note that, when the RRC release message explicitly or implicitly includes information indicating that the eDRX parameters for the deactive state have the same values ​​as the eDRX parameters for the idle state, the terminal 10 may recognize that the eDRX parameters for the deactive state have the same values ​​as the eDRX parameters for the idle state. In this case, the terminal 10 may set the eDRX parameters for the deactive state to the same values ​​as the eDRX parameters for the idle state.

[0077] When setting the determined eDRX parameters in the terminal 10, the base station 20 may include the eDRX parameters for the inactive state in another RRC message transmitted from the base station 20 to the terminal 10, instead of the RRC release message. Examples of the other RRC messages include an RRC reconfiguration message, an RRC reestablishment message, an RRC resumption request (RRCResumeRequest / RRCResumeRequest1) message, an RRC resumption (RRCResume) message, an RRC setup (RRCSetup) message, and the like.

[0078] The base station 20-A also transmits a message (N2 message) including the determined "eDRX parameters" for the inactive state to the core network 30 (S309). Specifically, the base station 20-A transmits an initial context setup response message, which is a response message to the initial context setup request, to the core network 30. Here, in order to notify the core network 30 of the "eDRX parameters" for the inactive state determined by the base station 20-A, the base station 20-A transmits the eDRX parameters for the inactive state by including them in the initial context setup response. Note that the eDRX parameters for the inactive state may be part of the core network assist information related to RRC inactivity included in the initial context setup response. In addition to the initial context setup response message, the N2 message also includes a UE context modification response message, a handover request acknowledge message, a path switch request message, and the like. The base station 20-A may include eDRX parameters for the inactive state in these N2 messages and transmit them to the core network 30.

[0079] Note that, when the "eDRX parameters" for the idle state received from the core network 30 differ from the "eDRX parameters" for the inactive state determined in the previous step S306, the base station 20-A may transmit a message including the "eDRX parameters" for the inactive state to the core network 30. For example, when the start position of the PTW calculated from the "eDRX parameters" for the idle state differs from the start position of the PTW calculated from the "eDRX parameters" for the inactive state, the base station 20-A transmits a message including the "eDRX parameters" for the inactive state to the core network 30.

[0080] Next, when the PTW start position calculated from the "eDRX parameters" for the idle state determined in the previous step S301 differs from the PTW start position calculated from the "eDRX parameters" for the inactive state included in the message received from the base station 20-A, the core network 30 may change the "eDRX parameters" for the idle state so that the PTW start position for the idle state becomes the same as the PTW start position calculated from the "eDRX parameters" for the inactive state (S310). For example, when the core network 30 receives a message including the "eDRX parameters" for the inactive state from the base station 20-A, the "eDRX parameters" for the idle state may be changed to match the "eDRX parameters" for the inactive state. In addition, for example, if the number of PTW start positions in a PH specified by the "eDRX parameters" for the idle state is made equal to the number of PTW start positions in a PH specified by the "eDRX parameters" for the inactive state, the core network 30 may change the "eDRX parameters" for the idle state so that the number of PTW start positions in a PH specified by the "eDRX parameters" for the idle state becomes the same as the number of PTW start positions in a PH specified by the "eDRX parameters" for the inactive state.

[0081] Next, the core network 30 transmits a NAS message including the changed "eDRX parameters" for the idle state to the terminal 10 in order to set the "eDRX parameters" in the terminal 10 (S311). Note that the NAS message may be a Registration Accept message, a Service Accept message, an Identity Request message, a Notification message, or the like.

[0082] The terminal 10 changes the "eDRX parameters" for the idle state set in the previous step S303 to the "eDRX parameters" for the idle state included in the NAS message (S312).

[0083] Thereafter, the terminal 10 monitors control channel candidates in the paging search space at a PTW in a PH indicated by the set eDRX parameters for an idle state or eDRX parameters for an inactive state, as in the description of Fig. 5. Furthermore, when transmitting a paging message, the base station 20 transmits DCI in the paging search space at a PTW in a PH indicated by the eDRX parameters for an idle state or eDRX parameters for an inactive state.

[0084] 7, the processing procedure of step S311 may be omitted, and the terminal 10 may change the eDRX parameters for the idle state by itself in the processing procedure of step S312. For example, when the PTW start position calculated from the "eDRX parameters" for the idle state notified in the processing procedure of step S302 differs from the PTW start position calculated from the "eDRX parameters" for the inactive state notified in the processing procedure of step S307, the terminal 10 may change the "eDRX parameters" for the idle state so that the PTW start positions are the same. For example, the terminal 10 may change the "eDRX parameters" for the idle state by itself so that they match the "eDRX parameters" for the inactive state.

[0085] 5 to 7 described above, the process steps related to either the request and setting of the "eDRX parameters" for the idle state or the "eDRX parameters" for the inactive state may be omitted. For example, the process steps related to the "eDRX parameters" for the inactive state may be omitted from the process steps of steps S100 to S103 in FIG.

[0086] FIG. 8 is a diagram illustrating an example of a paging procedure when a terminal is in an idle state or an inactive state.

[0087] When the terminal 10 is in an idle state, the base stations 20-A and 20-B do not store a context that stores information about the “eDRX parameters” for the idle state that are set for the terminal 10.

[0088] In this case, the core network 30 notifies each base station 20 (assumed to be the base stations 20-A and 20-B here) in the tracking area in which the terminal 10 is located of the "eDRX parameters" for the idle state determined by the core network 30. Specifically, when a paging trigger is established (S400), the core network 30 transmits the "eDRX parameters" for the idle state to the base stations 20-A and 20-B by a paging message (S401, S402).

[0089] By receiving the "eDRX parameters" for the idle state from the core network 30, the base stations 20-A and 20-B can recognize the "eDRX parameters" for the idle state set in the terminal 10. Then, the base stations 20-A and 20-B execute paging processing for the terminal 10 based on the "eDRX parameters" for the idle state (S403, S404). That is, the core network 30 executes paging processing for the terminal 10 on a tracking area basis.

[0090] On the other hand, when the terminal 10 is in an inactive state, the base station among the base stations 20-A and 20-B that last communicated with the terminal 10 (also called the Last Serving gNB; in the example shown in FIG. 8, base station 20-A) stores the "eDRX parameters" for the inactive state set for the terminal 10 in its context. However, the other base station (in the example shown in FIG. 8, base station 20-B) does not store the context of the terminal 10, and therefore naturally does not store the "eDRX parameters" for the inactive state.

[0091] In this case, when a paging trigger is established, the base station 20-A notifies the base station 20-B of "eDRX parameters" for the inactive state. Specifically, when a paging trigger is established (S405), the base station 20-A transmits "eDRX parameters" for the inactive state to another base station 20-B located in the same RAN notification area as the base station 20-A by RAN paging using a RAN paging message (S406).

[0092] By receiving the "eDRX parameters" for the inactive state from the base station 20-A, the base station 20-B can recognize the "eDRX parameters" for the inactive state set in the terminal 10. Then, the base stations 20-A and 20-B execute paging processing for the terminal 10 based on the "eDRX parameters" for the inactive state (S407, S408). That is, the base stations 20-A and 20-B execute paging processing for the terminal 10 on a RAN area basis.

[0093] According to the above-described processing procedure, the core network 30 can determine the eDRX parameters for the idle state and the eDRX parameters for the inactive state and notify the terminal 10. Furthermore, the terminal 10 that wishes to enable eDRX can request the base station 20 or the core network 30 to notify (set) the eDRX parameters for the idle state and the eDRX parameters for the inactive state. Furthermore, in the above-described processing procedure, when the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state, for example, the eDRX parameters for the inactive state are omitted. This makes it possible to reduce the amount of data of the NAS message, the N2 message, and / or the RRC message.

[0094] <Specification change example> Figures 9 to 25 are diagrams showing examples of specification changes in the 3GPP specifications. The underlined parts in Figures 9 to 25 indicate specifications of information elements that store fields indicating eDRX parameters and values ​​that are set in the fields indicating eDRX parameters.

[0095] Fig. 9 shows an example of specification changes of "eDRX parameters" included in a registration request and registration accept message. As shown in Fig. 9, the area storing "eDRX parameters" has a 4-octet area, and "Paging Time Window", "eDRX value" and "Number of Paging Time Window" are stored in two octets of the 4 octets (more specifically, the third and fourth octets). Also, "Number of Paging Time Window" is stored in the fourth octet area. "Number of Paging Time Window" in Fig. 9 corresponds to the number of start positions of PTW in PH. Also, "eDRX value" corresponds to an eDRX cycle. Fig. 10 corresponds to a specific example of "Number of Paging Time Window".

[0096] Fig. 11 shows an example of specification rules for Requested extended DRX Parameters, which are setting information related to eDRX, as an example of information transmitted by the Registration Request message described in the processing procedures of step S100 in Fig. 5, step S200 in Fig. 6, and step S300 in Fig. 7. Specifically, the Requested extended DRX Parameters stores the eDRX parameters shown in Fig. 9.

[0097] Fig. 12 shows an example of specification rules for Negotiated extended DRX parameters, which are setting information related to eDRX, as an example of information transmitted by the Registration Accept message described in the processing procedures of step S102 in Fig. 5, step S202 in Fig. 6, and step S302 in Fig. 7. Specifically, the eDRX parameters shown in Fig. 9 are stored in the Negotiated extended DRX parameters.

[0098] The underlined parts in FIG. 13 indicate examples of specification changes related to the contents of the paging message described in the processing procedures of steps S401 and S402 in FIG. 8 and the operation of base station 20 described in the processing procedures of steps S403 and S404.

[0099] Fig. 14 shows an example of specifications related to Core Network Assistance Information for RRC INACTIVE, which is setting information related to eDRX, as an example of information transmitted by the initial context setup request message described in the processing procedure of step S202 in Fig. 6 and step S304 in Fig. 7. The Core Network Assistance Information for RRC INACTIVE stores eDRX parameters shown in Figs. 23 to 25, which will be described later.

[0100] FIG. 15 shows an example of a specification change when Core Network Assistance Information for RRC INACTIVE, which is configuration information related to eDRX, is added to the initial context setup response message described in the processing procedures of step S204 in FIG. 6 and step S309 in FIG.

[0101] FIG. 16 shows an example of a specification change related to Core Network Assistance Information for RRC INACTIVE, which is configuration information related to eDRX, as an example of information transmitted by the UE context change request message described in the processing procedure of step S202 in FIG. 6 and step S304 in FIG. 7.

[0102] FIG. 17 shows an example of a specification change when Core Network Assistance Information for RRC INACTIVe, which is setting information related to eDRX, is added to the UE context modification response message described in the processing procedure of step S204 in FIG. 6 and step S309 in FIG. 7.

[0103] FIG. 18 shows an example of specification rules for Core Network Assistance Information for RRC INACTIVE, which is setting information related to eDRX, as an example of information transmitted by the handover request message described in the processing procedure of step S202 in FIG. 6 and step S304 in FIG. 7.

[0104] FIG. 19 shows an example of a specification change when Core Network Assistance Information for RRC INACTIVE, which is setting information related to eDRX, is added to the handover request response message, as described in the processing procedure of step S204 in FIG. 6 and step S309 in FIG.

[0105] FIG. 20 shows an example of a specification change when Core Network Assistance Information for RRC INACTIVE, which is setting information related to eDRX, is added to the path change request message described in the processing procedure of step S204 in FIG. 6 and step S309 in FIG.

[0106] FIG. 21 shows an example of specification for Core Network Assistance Information for RRC INACTIVE, which is configuration information related to eDRX, as an example of information transmitted by the path change request response message described in the processing procedure of step S202 in FIG. 6 and step S304 in FIG. 7.

[0107] Fig. 22 shows an example of specification rules for Paging eDRX Information, which is setting information related to eDRX, as an example of information transmitted by a paging message described in the processing procedure of steps S401 and S402 in Fig. 8. The Paging eDRX Information stores eDRX parameters shown in Figs. 24 and 25, which will be described later.

[0108] Fig. 23 shows an example of specifications related to Core Network Assistance Information for RRC INACTIVE described in Fig. 14 to Fig. 21. The format of Paging eDRX information is shown in Fig. 24 and Fig. 25 described later.

[0109] FIG. 24 shows an example of a change in the specifications of information (Paging eDRX Information) regarding eDRX parameters included in the paging message described in FIG.

[0110] Figure 25 shows an example of a change in the format of the Paging eDRX information shown in Figure 23. "Number of Paging Time Window" corresponds to the number of start positions of PTW in PH.

[0111] <Hardware configuration> 26 is a diagram showing an example of a hardware configuration of each device in a wireless communication system. Each device in the wireless communication system 1 (e.g., a terminal 10, a base station 20, a core network 30, etc.) includes a processor 11, a storage device 12, a communication device 13 that performs wired or wireless communication, and an input device that accepts various input operations and an input / output device 14 that outputs various information.

[0112] 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 the present 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 of the devices may be called a computer.

[0113] The storage device 12 is configured with, 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.).

[0114] 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.

[0115] The RF device performs, for example, D / A conversion, modulation, frequency conversion, power amplification, etc. on the digital baseband signal received from the BB device to generate a radio signal to be transmitted from the antenna. The RF device also performs frequency conversion, demodulation, A / D conversion, etc. on the radio signal received from the antenna to generate a digital baseband signal and transmit it to the BB device. The BB device performs a process of converting the digital baseband signal into a packet, and a process of converting the packet into a digital baseband signal.

[0116] 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.

[0117] 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. 26, or may include hardware not shown in Fig. 26. Furthermore, the hardware shown in Fig. 26 may be configured by one or more chips.

[0118] <Functional configuration> (Terminal) FIG. 27 is a diagram showing an example of a functional configuration of the terminal 10. The terminal 10 includes a receiving unit 101, a transmitting unit 102, and a control unit 103. All or a part of the functions realized by the receiving unit 101 and the transmitting unit 102 can be realized by using the communication device 13. All or a 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 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.

[0119] In the following description, eDRX parameters are an example of eDRX configuration values. Also, information elements of an RRC message, an N2 message, or an NAS message including eDRX parameters for an idle state (e.g., Negotiated extended DRX parameters, Core Network Assistance Information for RRC INACTIVE, Paging eDRX Information, etc.), an RRC message, an N2 message, and / or an NAS message are an example of first configuration information. The first configuration information may be referred to as configuration information. Also, information elements of an RRC message, an N2 message, or an NAS message including eDRX parameters for an inactive state (e.g., RAN-PagingExtendedDRX-Info, Negotiated extended DRX parameters, Core Network Assistance Information for RRC INACTIVE, Paging eDRX Information, etc.), an RRC message, an N2 message, and / or an NAS message are an example of second configuration information. In addition, an information element (e.g., Requested extended DRX parameters, etc.) of an RRC message, N2 message or NAS message containing eDRX parameters for the inactive state and / or the idle state that the terminal 10 desires (requests) to be configured, an RRC message, an N2 message and / or a NAS message are examples of a configuration request.

[0120] The receiving unit 101 receives a downlink signal. The receiving unit 101 may also receive information and / or data transmitted via the downlink signal. Here, "receiving" may include performing at least one of reception-related processes such as reception, demapping, demodulation, decoding, monitoring, and measurement of a wireless signal.

[0121] The receiving unit 101 receives first setting information including an eDRX setting value for an RRC idle state, the eDRX setting value including information specifying the number of start positions of a reception period in a predetermined H-SFN, which is set in response to a setting request transmitted from the transmitting unit 102. The PH indicated by the eDRX setting value is, for example, an example of a predetermined H-SFN. The PTW is, for example, an example of a reception period. The registration request message may be, for example, an example of a setting request.

[0122] The receiving unit 101 receives second setting information which is an eDRX setting value determined in response to a setting request transmitted from the transmitting unit 102 and includes information specifying the number of start positions of a reception period in a specified H-SFN, and which includes an eDRX setting value for an RRC inactive state.

[0123] The receiving unit 101 may receive a NAS message including the first setting information and / or the second setting information from the core network 30. The registration response message is an example of a NAS message.

[0124] The receiving unit 101 may receive a NAS message including the first setting information from the core network 30, and may receive an RRC message including the second setting information from the base station 20.

[0125] The start position of the reception period may be determined by inputting information specifying the number of start positions of the reception period in a predetermined H-SFN into a predetermined formula. The above-mentioned formulas 2, 3, 4, and 5 are examples of the predetermined formula.

[0126] The first setting information may have a four-octet area, and the eDRX setting value may be stored in a two-octet area of ​​the four octets.

[0127] The second setting information may have a four-octet area, and the eDRX setting value may be stored in a two-octet area of ​​the four octets.

[0128] The transmitting unit 102 transmits an uplink signal. The transmitting unit 102 may also transmit information and / or data to be transmitted via the uplink signal. Here, "transmitting" may include performing processing related to transmission, such as at least one of encoding, modulation, mapping, and transmission of a radio signal.

[0129] The transmitting unit 102 transmits a setting request for requesting setting of an eDRX setting value for an RRC idle state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN.

[0130] The transmitting unit 102 transmits a setting request including an eDRX setting value for an RRC inactive state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN.

[0131] The control unit 103 performs various processes related to eDRX based on the eDRX setting value received by the receiving unit 101. In addition, the control unit 103 performs control so as to monitor a control channel candidate (PDCCH Candidate) in a search space for paging in a reception period in a predetermined H-SFN indicated by the eDRX setting value for the RRC idle state in the RRC idle state.

[0132] In addition, in the RRC inactive state, the control unit 103 controls to monitor control channel candidates within the paging search space during a reception period in a specified H-SFN indicated by the eDRX setting value for the RRC inactive state.

[0133] In the RRC idle state, the control unit 103 controls to execute eDRX by matching the number of start positions of a reception period in a predetermined H-SFN with the number (the number of start positions of a reception period specified in the first setting information) specified by the first setting information received by the receiving unit 101. That is, the control unit 103 recognizes that the number specified by the first setting information is the number of start positions of a reception period in a predetermined H-SFN applied to the eDRX process for the RRC idle state, and performs the eDRX process.

[0134] In the RRC inactive state, the control unit 103 controls to execute eDRX by matching the number of start positions of reception periods in a predetermined H-SFN with the number (the number of start positions of reception periods specified in the second setting information) specified by the second setting information received by the receiving unit 101. That is, the control unit 103 recognizes that the number specified by the second setting information is the number of start positions of reception periods in a predetermined H-SFN applied to the eDRX process for the RRC inactive state, and performs the eDRX process.

[0135] When the start position of the reception period in a specified H-SFN specified by the first setting information received by the receiving unit 101 differs from the start position of the reception period in a specified H-SFN specified by the second setting information received by the receiving unit 101, the control unit 103 may change the eDRX setting value so that the start position of the reception period in a specified H-SFN specified by the first setting information becomes identical to the start position of the reception period in a specified H-SFN specified by the second setting information.

[0136] (base station) FIG. 28 is a diagram showing an example of a functional configuration of the base station 20. The base station 20 includes a receiving unit 201, a transmitting unit 202, and a control unit 203. All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 can be realized by using the communication device 13. All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 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 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.

[0137] The receiving unit 201 receives an uplink signal. The receiving unit 201 may also receive information and / or data transmitted via the uplink signal. The receiving unit 201 also receives request information including an eDRX setting value for an RRC inactive state from the terminal 10.

[0138] The receiving unit 201 receives first setting information including an eDRX setting value for an RRC idle state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN.

[0139] The transmitting unit 202 transmits a downlink signal. The transmitting unit 202 may also transmit information and / or data transmitted via the downlink signal. The transmitting unit 202 also transmits, to the terminal 10, first setting information including an eDRX setting value for an RRC idle state. The transmitting unit 202 also transmits, to the terminal 10, second setting information including an eDRX setting value to be applied to the terminal 10 in an RRC inactive state.

[0140] The transmitting unit 202 transmits, based on the first setting information received by the receiving unit 201, second setting information including an eDRX setting value for an RRC inactive state, which is an eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN, to the core network 30 or the terminal 10.

[0141] The control unit 203 controls paging processing for the terminal 10 in the RRC idle state or the RRC inactive state. The control unit 203 also controls the terminal 10 in the RRC idle state to transmit downlink control information (e.g., DCI) within the search space for paging in the PTW (reception period) in the PH (predetermined H-SFN) indicated by the eDRX setting value included in the first setting information. The control unit 203 also controls the terminal 10 in the RRC inactive state to transmit downlink control information (e.g., DCI) within the search space for paging in the PTW (reception period) in the PH (predetermined H-SFN) indicated by the eDRX setting value included in the second setting information.

[0142] The control unit 203 controls the terminal 10 in the RRC inactive state to transmit downlink control information in the reception period in the predetermined H-SFN by matching the number of start positions of the reception period in the predetermined H-SFN with the number specified by the second setting information. That is, the control unit 203 recognizes that the number specified by the second setting information is the number of start positions of the reception period in the predetermined H-SFN applied to the eDRX process for the RRC inactive state, and performs the paging process.

[0143] (Core Network) FIG. 29 is a diagram showing an example of a functional configuration of the core network 30. The core network 30 includes a receiving unit 301, a transmitting unit 302, and a control unit 303. All or a part of the functions realized by the receiving unit 301 and the transmitting unit 302 can be realized by using the communication device 13. All or a part of the functions realized by the receiving unit 301 and the transmitting unit 302 and the control unit 303 can be realized by the processor 11 executing a program stored in the storage device 12. The program can be stored in a storage medium. The storage medium 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.

[0144] The receiving unit 301 receives an uplink signal. The receiving unit 301 may also receive information and / or data transmitted via the uplink signal. The receiving unit 301 also receives request information including an eDRX setting value for an RRC idle state, or request information including an eDRX setting value for an RRC inactive state from the terminal 10.

[0145] The receiving unit 301 receives a setting request from the terminal 10, the setting request being an eDRX setting value including information specifying the number of start positions of a reception period in a predetermined H-SFN, and requesting setting of an eDRX setting value for an RRC idle state and / or setting of an eDRX setting value for an RRC inactive state. The registration request message is an example of the setting request.

[0146] The transmitting unit 302 transmits a downlink signal. The transmitting unit 302 may also transmit information and / or data transmitted via the downlink signal. The transmitting unit 302 transmits, to the terminal 10, first setting information including an eDRX setting value for an RRC idle state, which is an eDRX setting value including information specifying the number of start positions of a reception period in a predetermined H-SFN. The transmitting unit 302 transmits, to the terminal 10, second setting information including an eDRX setting value for an RRC inactive state, which is an eDRX setting value including information specifying the number of start positions of a reception period in a predetermined H-SFN.

[0147] In response to the setting request received by the receiving unit 301, the transmitting unit 302 transmits to the terminal 10 first setting information including an eDRX setting value for an RRC idle state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN.

[0148] In response to the setting request received by the receiving unit 301, the transmitting unit 302 transmits to the terminal 10 second setting information including an eDRX setting value for an RRC inactive state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN.

[0149] The transmitter 302 transmits a paging message to the base station 20, the paging message including an eDRX setting value for the RRC idle state, the eDRX setting value including information specifying the number of start positions of a reception period in a specified H-SFN.

[0150] The control unit 303 controls paging processing for the terminal 10 in the RRC idle state or the RRC inactive state.

[0151] <Supplementary Information> The eDRX parameters, information elements including the eDRX parameters, RRC messages including the eDRX parameters, and / or NAS messages including the eDRX parameters are examples of eDRX configuration information.

[0152] Explicitly or implicitly including information indicating that the eDRX parameters for the inactive state are the same value as the eDRX parameters for the idle state may mean, for example, that each eDRX parameter for the inactive state includes a specific character string or number such as NULL or "absent". Also, information indicating that the eDRX parameters for the inactive state are the same value as the eDRX parameters for the idle state may be set for each eDRX parameter. For example, when the time length of the PTW is the same but the number of eDRX cycles and the start positions of the PTW are different, information indicating that the eDRX parameters for the inactive state are the same value as the eDRX parameters for the idle state may be set for the time length of the PTW.

[0153] The information indicating that the eDRX parameters for the idle state have the same value as the eDRX parameters for the idle state may be replaced with information indicating that the eDRX parameters for the idle state have the same value as the eDRX parameters for the idle state. That is, in the processing procedures described in FIG. 5 to FIG. 7, when "information indicating that the eDRX parameters for the idle state have the same value as the eDRX parameters for the deactive state" is set in the eDRX parameters for the idle state, the terminal 10, the base station 20, and the core network 30 may recognize that the eDRX parameters for the idle state are the same as the eDRX parameters for the deactive state. Also, the information indicating that the eDRX parameters for the idle state have the same value as the eDRX parameters for the deactive state may be set for each eDRX parameter.

[0154] "Monitoring control channel candidates within a paging search space" may also be expressed as "monitoring control channel candidates within a search space set set by paging search space information (pagingSearchSpace)."

[0155] In the above embodiment, an example of the first time unit may be one hyperframe (10.24 sec), an example of the second time unit may be one radio frame (10 ms), and an example of the third time unit may be one subframe (1 ms). The second time unit may be defined as a time shorter than the first time unit, and the third time trough may be defined as a time shorter than the second time unit. An example of a number indicating the position of the periodically repeated second time unit may be SFN, and an example of a number indicating the position of the periodically repeated first time unit may be H-SFN. For example, H-SFN may be expressed as the first time interval at a position indicated by a predetermined number in the periodically repeated first time interval. PH may be set to a plurality of hyperframes among H-SFNs from 0 to 1023.

[0156] Various signals, information, and parameters in the above embodiment may be signaled in any layer. That is, the above 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). In addition, notification of predetermined information is not limited to being explicitly performed, and may be performed implicitly (e.g., by not notifying information or by using other information).

[0157] In addition, 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. Also, an RB may be named in any way as long as it is a frequency unit having a predetermined number of subcarriers. Also, a registration response message may be called a registration approval message.

[0158] In addition, the uses of the terminal 10 in the above embodiment (e.g., RedCap, IoT, etc.) are not limited to those exemplified, and as long as it has similar functions, it may be used for any purpose (e.g., eMBB, URLLC, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.).

[0159] Furthermore, the format of the various information is not limited to that in the above embodiment, and may be changed as appropriate to bit representation (0 or 1), boolean (true or false), integer value, character, etc. Furthermore, the singular and plural in the above embodiment may be changed interchangeably.

[0160] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs.

Claims

1. A transmitter that transmits a radio resource control (RRC) release message to a terminal, the message including information indicating an eDRX cycle for an RRC inactive state and information indicating a length of a PTW for the RRC inactive state; A control unit that transmits downlink control information to the terminal in the RRC inactive state on a physical downlink control channel at a paging opportunity in a PTW period, A hyper system frame number (H-SFN) of a paging hyperframe (PH) is determined based on the information indicating the eDRX cycle; An end position of the PTW in the PH is determined based on information indicating a length of the PTW; The transmission unit notifies a core network device of an eDRX cycle for the RRC inactive state and a length of a PTW for the RRC inactive state; The core network device is an AMF. Base station.

2. The eDRX cycle for the RRC inactive state and the length of the PTW for the RRC inactive state are included in the N2 message. The base station according to claim 1 .

3. The transmission unit notifies another base station of the eDRX cycle for the RRC inactive state and the length of the PTW for the RRC inactive state. The base station according to claim 1 or 2.

4. The information indicating an eDRX cycle for an RRC inactive state is first information, The information indicating the length of the PTW for the RRC inactive state is second information, the PTW is a first PTW, A NAS message including third information indicating an eDRX cycle and fourth information indicating a length of a PTW is transmitted from the core network device; The control unit transmits downlink control information to the terminal in an RRC idle state on a physical downlink control channel at a paging opportunity in a period of a second PTW determined based on the third information and the fourth information. The base station according to claim 1 .

5. Transmitting a radio resource control (RRC) release message to a terminal, the message including information indicating an eDRX cycle for an RRC inactive state and information indicating a length of a PTW for the RRC inactive state; Transmitting downlink control information to the terminal in the RRC inactive state on a physical downlink control channel at a paging opportunity in a PTW period; A hyper system frame number (H-SFN) of a paging hyperframe (PH) is determined based on the information indicating the eDRX cycle; An end position of the PTW in the PH is determined based on information indicating a length of the PTW; Notifying a core network device of an eDRX cycle for the RRC inactive state and a length of a PTW for the RRC inactive state; The core network device is an AMF. Base station method.

6. The eDRX cycle for the RRC inactive state and the length of the PTW for the RRC inactive state are included in the N2 message. The method according to claim 5.

7. Notifying other base stations of the eDRX cycle for the RRC inactive state and the length of the PTW for the RRC inactive state The method according to claim 5 or claim 6.

8. The information indicating an eDRX cycle for an RRC inactive state is first information, The information indicating the length of the PTW for the RRC inactive state is second information, the PTW is a first PTW, A NAS message including third information indicating an eDRX cycle and fourth information indicating a length of a PTW is transmitted from the core network device; Transmitting downlink control information to the terminal in an RRC idle state on a physical downlink control channel at a paging opportunity in a period of a second PTW determined based on the third information and the fourth information. The method according to claim 5.

9. A receiver that receives a radio resource control (RRC) release message from a base station, the radio resource control (RRC) release message including first information indicating an eDRX cycle for an RRC inactive state and second information indicating a length of a PTW for the RRC inactive state; a control unit that, in the RRC inactive state, determines a first hyper system frame number (H-SFN) of a first paging hyperframe (PH) based on the first information, determines an end position of a first PTW in the first PH based on the second information, and monitors physical downlink control channel candidates at paging occasions in a period of the first PTW; The receiving unit receives a NAS message from a core network device, the NAS message including third information indicating an eDRX cycle and fourth information indicating a length of a PTW; The control unit, in an RRC idle state, determines a second H-SFN of a second PH based on the third information, determines an end position of a second PTW in the second PH based on the fourth information, and monitors physical downlink control channel candidates at paging occasions in a period of the second PTW; The eDRX cycle for the RRC inactive state and the length of the PTW for the RRC inactive state are notified from the base station to the core network device; The core network device is an AMF. Terminal.

10. The eDRX cycle for the RRC inactive state and the length of the PTW for the RRC inactive state are included in the N2 message. The terminal according to claim 9.

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