Terminal, base station and wireless communication method

Abstract

To provide a terminal, a base station, and a wireless communication method capable of notifying a terminal of eDRX setting information applied to the terminal in an RRC inactive state.SOLUTION: A terminal a receiving unit that receives first configuration information including an eDRX setting value for an RRC inactive state, and a control unit that controls to monitor a control channel candidate in a paging search space in a reception period in a predetermined H-SFN indicated by the eDRX setting value included in the first setting information in the RRC inactive state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a terminal, a base station, and a wireless communication method. [Background technology]

[0002] The Third Generation Partnership Project (3GPP), an international standardization organization, has specified Release 15 of New Radio (NR), a fifth-generation (5G) RAT, as the successor to Long Term Evolution (LTE), a 3.9th-generation radio access technology (RAT), and LTE-Advanced, a fourth-generation RAT (see, for example, Non-Patent Document 1).

[0003] Furthermore, LTE (Long Term Evolution) takes into consideration the existence of terminals with further restrictions on power consumption, such as IoT (Internet of Things) devices, and has introduced a technology called eDRX (extended DRX) that reduces power consumption by limiting the period during which wireless signals can be received (e.g., 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 [Problem to be solved by the invention]

[0005] Currently, 3GPP has begun studying functions for new IoT terminals that use NR for radio access. The functions under study include the aforementioned eDRX. NR specifies that a terminal can be in three states: RRC idle state, RRC inactive state, and RRC connected state. However, the current 3GPP specifications do not specify a procedure for notifying a terminal of eDRX configuration information to be applied to a terminal in the RRC inactive state.

[0006] The present disclosure has been made in consideration of these circumstances, and one of its objectives is to provide a terminal, a base station, and a wireless communication method that enable notifying a terminal of eDRX configuration information that is applied to a terminal in an RRC inactive state. [Means for solving the problem]

[0007] A terminal according to one embodiment of the present disclosure has a receiving unit that receives first setting information including an eDRX setting value for an RRC inactive state, and a control unit that, in the RRC inactive state, controls to monitor control channel candidates within a paging search space during a reception period in a specified H-SFN indicated by the eDRX setting value included in the first setting information. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a terminal, a base station, and a wireless communication method that enable notifying a terminal of eDRX configuration information applied to a terminal in an RRC inactive state. [Brief explanation 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. [Figure 2] FIG. 2 is a diagram illustrating an example of a state transition of a terminal. [Figure 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. [Figure 5] FIG. 5 is a diagram illustrating an example of a processing procedure when eDRX parameters for the inactive state are managed by the core network. [Figure 6] FIG. 6 is a diagram illustrating an example of a processing procedure in which setting information related to eDRX for the inactive state is managed by a base station. [Figure 7] FIG. 7 is a diagram showing an example of specification changes in the 3GPP specifications. [Figure 8] FIG. 8 is a diagram showing an example of specification changes in the 3GPP specifications. [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 illustrating an example of the hardware configuration of each device in the wireless communication system. [Figure 13] FIG. 13 is a diagram illustrating an example of a functional configuration of a terminal. [Figure 14] FIG. 14 is a diagram illustrating an example of the functional configuration of a base station. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0012] The radio access technology (RAT) of the wireless communication system 1 is assumed to be, for example, NR, but is not limited to this, and various RATs can be used, such as LTE, LTE-Advanced, or a sixth generation or later RAT.

[0013] The terminal 10 is a predetermined terminal or device such as a smartphone, a personal computer, an in-vehicle terminal, an in-vehicle device, a stationary device, a telematics control unit (TCU), etc. The terminal 10 may also be called a user equipment (UE), a mobile station (MS), a user terminal, a radio apparatus, a subscriber terminal, an access terminal, etc. The terminal 10 may be either mobile or fixed. The terminal 10 is configured to be able to communicate using, for example, NR as a RAT.

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

[0015] A RedCap terminal is expected to have higher performance than a terminal for low-power wide area (LPWA) communications, and the carrier used by the RedCap terminal may have a bandwidth of, for example, 20 MHz, 50 MHz, or 100 MHz. LPWA includes, for example, Category 1, Long Term Evolution for Machine-type communication (LTE-M) operating on an LTE-based RAT, and Narrow Band IoT (NB-IoT). 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). As such, a RedCap terminal is expected 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 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 also be called a gNodeB (gNB), en-gNB, a Next Generation-Radio Access Network (NG-RAN) node, an 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 a single node, and may be configured with multiple nodes (for example, a combination of a lower node such as a DU and an upper node such as a CU).

[0017] The core network 30 is, for example, a core network (5G Core Network: 5GC) corresponding to NR, but is not limited thereto. Devices on the core network 30 (hereinafter also referred to as "core network devices") perform mobility management such as paging and location registration of the terminal 10. The core network device may be connected to the base station 20 via a predetermined interface (for example, S1 or NG interface).

[0018] The core network device includes, for example, 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 performs transmission control of the U plane, 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.

[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 state of the terminal 10 defined in NR will be described. The RRC state of the terminal 10 includes an RRC idle state (hereinafter referred to as "idle state"), an RRC inactive state (hereinafter referred to as "inactive state"), and an RRC connected state (hereinafter referred to as "connected state").

[0021] Fig. 2 is a diagram showing an example of state transition of the terminal 10. In Fig. 2, the idle state is a state in which an 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 the 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 inactive state does not exist in LTE and is a new RRC state defined in NR. A 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. Like the idle state, the inactive state allows for power saving of the terminal 10, but unlike the idle state, the terminal 10, the base station 20, and the core network 30 hold an RRC context and a NAS context.

[0024] Furthermore, in NR, a new RAN Notification Area (RNA) is defined, which is an area obtained by subdividing a Tracking Area (TA), and a base station 20 manages the RAN Notification Area in which terminals 10 in a connected state and an inactive state exist. NR also introduces a technology called "RAN paging" that performs paging processing in units of RAN Notification Areas, which is used when calling a terminal 10 in an inactive state. In RAN paging, a paging signal is simultaneously transmitted from multiple base stations 20 that constitute a RAN notification area in which terminals 10 in an inactive state exist. Upon receiving the paging signal, a terminal 10 in an inactive state resumes the RRC connection and transitions to a connected state.

[0025] The connected state is a state in which the 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 reception of the PDSCH (Physical Downlink Shared Channel) based on detected DCI (Downlink Control Information). The terminal 10 in the connected state transitions to the idle state when the RRC connection is released, and transitions to the inactive state when the RRC connection is suspended.

[0026] <Conventional eDRX technology> Here, we will explain the conventional eDRX (enhanced DRX) technology specified in LTE. LTE specifies subframes with a time length of 1 ms, radio frames with a time length of 10 ms, and hyperframes with a time length of 10.23 seconds. The position of a radio frame is represented by a system frame number (SFN) ranging from 0 to 1023. Furthermore, to manage a time period longer than 1024 radio frames, hyperframes with a length of SFNs ranging from 0 to 1023 (i.e., 10.24 seconds) are specified. Hyperframes are represented by hyper-SFNs (H-SFNs) with numbers ranging from 0 to 1023.

[0027] FIG. 3 is a diagram for explaining DRX 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) during 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 during the PO period and does not transmit a paging signal during other periods. A terminal 10 that receives a paging signal within the PO period establishes communication with the base station 20 and transitions to a connected state. One PO exists per 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 during a PO period that exists within a period called a PTW (Paging Time Window). One PTW is set within a hyperframe called a PH (Paging Hyperframe). One PH exists per eDRX cycle. The eDRX cycle is a maximum of 2.91 hours (i.e., 1024 hyperframes) for an NB-IoT terminal 10, and a maximum of approximately 44 minutes (i.e., 256 hyperframes) for a terminal 10 other than an NB-IoT terminal 10.

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

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

[0031] (Equation 1) H-SFN mod TeDRX,H = (UE_ID_H mod TeDRX,H) "TeDRX,H" indicates the eDRX cycle and is set to an integer multiple of the hyperframe length. UE_ID_H is the most significant 10 or 12 bits of the hashed ID determined based on the 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, is expressed by the following Equations 2 and 3.

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

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

[0035] <Issues in Implementing eDRX in NR> Currently, in 3GPP, studies are underway to implement eDRX in NR. Here, in LTE, a processing procedure for notifying eDRX parameters from the core network 30 to the terminal 10 using NAS messages is defined. Therefore, by applying this processing procedure to NR, it is possible to notify the eDRX parameters applied to the idle terminal 10 to the terminal 10. However, a processing procedure for notifying (setting) the eDRX parameters applied to the non-active terminal 10 to the terminal 10 is not defined in the current 3GPP (the first issue).

[0036] Similarly, LTE specifies a procedure for the terminal 10 to request notification of eDRX setting information from the core network 30 using an NAS message. Therefore, by applying this procedure to NR, the terminal 10 can request notification (setting) of eDRX parameters to be applied to the terminal 10 in an idle state from the core network 30. However, the current 3GPP does not specify a procedure for the terminal 10 to request notification (setting) of eDRX parameters to be applied to an inactive state (second problem).

[0037] In this embodiment, to solve the first problem, the eDRX parameters to be applied to the terminal 10 in the inactive state can be notified to the terminal 10 by using an NAS message or an RRC message. Also, in this embodiment, to solve the second problem, the terminal 10 can transmit the eDRX parameters to be applied to the terminal 10 in the inactive state to the base station 20 or the core network 30 in order to request eDRX operation in the inactive state.

[0038] In the following description, "eDRX parameters" may refer only to parameters that determine eDRX operation, such as the eDRX cycle and PTW, or may refer to parameters that determine DRX operation, such as the DRX cycle and PO position settings, in addition to parameters that determine eDRX operation. Also, "eDRX parameters for inactive state" refers to eDRX parameters that are applied to a terminal 10 in an inactive state. Also, "eDRX parameters for idle state" refers to eDRX parameters that are applied to a terminal 10 in an idle state.

[0039] <Procedure for achieving eDRX in an inactive state> When realizing eDRX in the inactive state, two methods are possible: a method in which the eDRX parameters for the inactive state are managed by the core network 30, and a method in which they are managed by the base station 20. In the following description, the process by which the terminal 10 performs paging may be the same as the process described in the conventional eDRX technology, unless otherwise specified.

[0040] 5 is a diagram showing an example of a processing procedure when eDRX parameters for the 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 to this.

[0041] A terminal 10 that desires to enable eDRX transmits a registration request message including "eDRX parameters" indicating the eDRX operation that the terminal desires to set to the core network 30 (S100). For example, a terminal 10 that desires eDRX operation in which the eDRX cycle is 2 hyperframes and the PTW is 1 second transmits a registration request to the core network 30 that includes eDRX parameters indicating that the eDRX cycle is 2 hyperframes and the PTW is 1 second.

[0042] Here, the terminal 10 may distinguish between “eDRX parameters” indicating eDRX operation for the idle state and “eDRX parameters” indicating eDRX operation for the inactive state and include them in the registration request message. For example, assume that the terminal 10 desires eDRX operation in which the eDRX cycle is 8 hyperframes and the PTW is 2 seconds in the idle state, and desires eDRX operation in which the eDRX cycle is 2 hyperframes and the PTW is 1 second 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 is 8 hyperframes and the PTW is 2 seconds, and “eDRX parameters for the inactive state” indicating that the eDRX cycle is 2 hyperframes and the PTW is 1 second in the inactive state.

[0043] Furthermore, when it is desired that the "eDRX parameters" for the deactive 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 deactive state have the same values ​​as the eDRX parameters for the idle state. For example, when the registration request message includes eDRX parameters for the idle state but does not include eDRX parameters for the deactive state (that is, when the eDRX parameters are "absent"), it may be implicitly indicated that the eDRX parameters for the deactive state are the same as the eDRX parameters for the idle state.

[0044] Next, the core network 30 determines 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 the eDRX parameters for the idle state and the 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 values ​​as the eDRX parameters included in the registration request, or may determine them to be values ​​different from the eDRX parameters included in the registration request.

[0045] 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 deactive state to the terminal 10 in order to set the determined eDRX parameters in the terminal 10 (S102). Note that if the determined eDRX parameters for the idle state and the eDRX parameters for the deactive state are identical, the core network 30 may explicitly or implicitly include information indicating that the eDRX parameters for the deactive state have the same values ​​as the eDRX parameters for the idle state in the registration response message. For example, if the registration response message includes the eDRX parameters for the idle state but not the eDRX parameters for the deactive state (that is, if the eDRX parameters are "absent"), the core network 30 may implicitly indicate that the eDRX parameters for the deactive state are the same as the eDRX parameters for the idle state.

[0046] The terminal 10 sets the eDRX parameters for the idle state and the eDRX parameters for the deactive state 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 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. Note that the registration request message and registration acceptance message described above are merely examples, and any NAS message may be used.

[0047] When the terminal 10 is in an idle state, it monitors control channel candidates in the paging search space at a PTW in the PH indicated by the eDRX parameters for the idle state that have been set. Furthermore, when transmitting 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 that has been set by the eDRX parameters for the idle state that have been set in the terminal 10. Furthermore, when the terminal 10 is in an inactive state, it monitors control channel candidates in the paging search space at a PTW in the PH that has been set by the eDRX parameters for the inactive state that have been set. Furthermore, when transmitting 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 that has been set by the eDRX parameters for the inactive state that have been set in the terminal 10.

[0048] According to the processing procedure described above, the core network 30 can determine eDRX parameters for the inactive state and notify the terminal 10. Furthermore, a terminal 10 that wishes to enable eDRX can request notification (setting) of the eDRX parameters for the inactive state from the core network 30. Furthermore, in the processing procedure described above, if 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 in the NAS message.

[0049] 6 is a diagram showing an example of a processing procedure when setting information related to eDRX for the inactive state is managed by the base station 20. For example, the terminal 10 that starts the registration process to the core network 30 transmits an RRC setup request (RRCSetupRequest) message to the base station 20 in order to establish an RRC connection with the base station 20 (S200). The base station 20 that receives the RRC setup request transmits an RRC setup (RRCSetup) message (S201).

[0050] Next, the terminal 10 transmits an RRC Setup Complete message to the base station 20. The RRC Setup Complete message includes a Registration Request message, which is an NAS message to be transmitted to the core network 30 (S202). The base station 20 extracts the Registration Request message included in the RRC Setup Complete message and transmits (transfers) it to the core network 30 (S203).

[0051] Here, in the processing procedure of step S202, the terminal 10 desiring to enable eDRX transmits a registration request message including "eDRX parameters" indicating the eDRX operation for the idle state that the terminal 10 desires to set. The core network 30 determines the eDRX parameters for the idle state based on the registration request message received from the terminal 10 (S204). The core network 30 determines the eDRX parameters for the idle 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 and / or the capabilities of the terminal 10, etc. The core network 30 may determine the eDRX parameters to be set in the terminal 10 to be the same values ​​as the eDRX parameters desired by the terminal 10, or may determine values ​​different from the eDRX parameters desired by the terminal 10.

[0052] Subsequently, the core network 30 transmits a registration response (Registration Accept) message including the determined eDRX parameters for the idle state to the terminal 10 in order to set the eDRX parameters in the terminal 10 (S205). The terminal 10 sets the eDRX parameters for the idle state and the eDRX parameters for the inactive state included in the registration response message (stores the eDRX parameters in the storage device 12) (S206).

[0053] The core network 30 transmits an initial context setup request message to the base station 20 to notify the base station 20 of information necessary for the terminal 10 to communicate (S207). Here, the core network 30 transmits the eDRX parameters for the idle state included in the initial context setup request 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 are included in the initial context setup request. They may also be part of Core Network Assistance Information for RRC INACTIVE. Note that messages transmitted and received between the base station 20 and the core network 30 are called N2 messages. In addition to the initial context setup request message, the N2 messages also include a UE context modification message, a handover resource allocation message, a path switch request message, and the like. The core network 30 may include eDRX parameters for the idle state in these N2 messages and transmit them to the base station 20. By receiving the NAS message including the eDRX parameters for the idle state, the base station 20 can recognize the eDRX parameters for the idle state desired by the terminal 10.

[0054] Subsequently, communication is started between the terminal 10 and the base station 20, and RRC messages are transmitted and received as necessary (S208). Examples of RRC messages transmitted from the terminal 10 to the base station 20 include 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, and an RRC resume complete (RRCResume Complete) message.

[0055] Here, the terminal 10 desiring to enable eDRX transmits "eDRX parameters" indicating the eDRX operation for the inactive state that the terminal 10 desires to set to the base station 20. The terminal 10 may include the eDRX parameters in an RRC setup request message (S200) or an RRC setup complete message (S202) and transmit the message to the base station 20. Alternatively, the terminal 10 may include the eDRX parameters in an RRC reconfiguration complete message, an RRC re-establishment request message, an RRC re-establishment complete message, an RRC resumption request message, an RRC resumption complete message, or the like (S208) and transmit the message to the base station 20.

[0056] The terminal 10 may include eDRX parameters for the inactive state in the RRC setup complete message, and may include eDRX parameters for the idle state in a Registration Request message included in the RRC setup complete message. Since it becomes possible to transmit the eDRX parameters for the idle state and the eDRX parameters for the inactive state at the same time, it is possible to simplify the processing logic of the terminal 10.

[0057] For example, assume that the terminal 10 desires eDRX operation in an inactive state with an eDRX cycle of 2 hyperframes and a PTW of 1 second. 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 and the PTW is 2 seconds.

[0058] Furthermore, when it is desired that the "eDRX parameters" for the deactive 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 deactive state have the same values ​​as the eDRX parameters for the idle state. For example, if the RRC setup complete message contains information indicating a request for the "eDRX parameters" for the deactive state (for example, the name of an information element that stores the eDRX parameters) but does not include specific eDRX parameters (that is, if the eDRX parameters are "absent"), it may be implicitly indicated that the eDRX parameters for the deactive state are the same as the eDRX parameters for the idle state.

[0059] Next, the base station 20 determines the eDRX parameters for the deactivation state to be set in the terminal 10 based on the eDRX parameters for the deactivation state received from the terminal 10 (S209). The base station 20 determines the eDRX parameters for the deactivation state to be set in the terminal 10, taking into consideration, for example, the eDRX parameters received from the terminal 10, the load of the wireless network, the attributes and / or the capabilities of the terminal 10, etc. The base station 20 may determine the eDRX parameters to be set in the terminal 10 to be the same values ​​as the eDRX parameters desired by the terminal 10, or may determine the eDRX parameters to be different values ​​from the eDRX parameters desired by the terminal 10.

[0060] Next, when instructing the terminal 10 to transition to the deactive state, the base station 20 transmits an RRC Release message including the determined eDRX parameters for the deactive state to the terminal 10 (S210). Note that if the determined eDRX parameters for the idle state and the eDRX parameters for the deactive state are identical, the base station 20 may explicitly or implicitly include in the RRC Release message information indicating that the eDRX parameters for the deactive state have the same values ​​as the eDRX parameters for the idle state. For example, if the RRC Release message contains information indicating that "eDRX parameters" for the deactive state are set (e.g., the name of an information element that stores the eDRX parameters) but does not include specific eDRX parameters (i.e., the eDRX parameters are "absent"), the base station 20 may implicitly indicate that the eDRX parameters for the deactive state are the same as the eDRX parameters for the idle state.

[0061] 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) (S211). Note that, if 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. Thereafter, as in the description of FIG. 5 , the terminal 10 monitors control channel candidates in the paging search space with a PTW in the PH indicated by the set eDRX parameters for the idle state or the eDRX parameters for the deactive state. Furthermore, when transmitting a paging message, the base station 20 transmits DCI in the paging search space with a PTW in the PH indicated by the eDRX parameters for the idle state or the eDRX parameters for the deactive state.

[0062] 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 RRCReconfiguration message, an RRCReestablishment message, an RRCResumeRequest / RRCResumeRequest1 message, an RRCResume message, an RRCSetup message, and the like.

[0063] According to the processing procedure described above, the base station 20 can determine the eDRX parameters for the inactive state and notify the terminal 10. Also, the terminal 10 that wishes to activate eDRX can request the base station 20 to notify (configure) the eDRX parameters for the inactive state.

[0064] In addition, the base station 20 includes the eDRX parameters for the inactive state in the RRC release message transmitted when transitioning the terminal 10 from the connected state to the inactive state. As a result, the base station 20 only needs to notify the eDRX parameters when it is necessary to configure the eDRX parameters for the terminal 10 for the inactive state, so that it becomes possible to efficiently utilize radio resources. Also, when the terminal 10 does not transition to the inactive state, it is not necessary to store the eDRX parameters for the inactive state, so that the memory capacity of the terminal 10 can be reduced.

[0065] Also, when including the eDRX parameters in an RRC message other than the RRC release message, depending on the timing of transitioning to the inactive state, the configuration of the eDRX parameters may not be in time, and there may be a time lag until the actual transition to the inactive state is completed. However, by including the eDRX parameters for the inactive state in the RRC release message, it becomes possible to eliminate the time lag and quickly transition to the inactive state.

[0066] In this embodiment, when the eDRX parameters for the inactive state are the same as the eDRX parameters for the idle state, the eDRX parameters for the inactive state can be omitted. As a result, duplicate data transmission is avoided, and the data volume of the RRC message can be reduced.

[0067] <Modified Example of eDRX Parameters> The terminal 10, base station 20, and core network 30 according to this embodiment may use eDRX parameters similar to those in LTE. That is, PH may be determined according to Equation 1, the start position of the PTW may be determined according to Equations 2 and 3, and the end position of the PTW may be determined according to Equation 4. In this case, the eDRX parameters include the eDRX cycle (TeDRX,H in Equations 1 and 3) and the time length of the PTW (L in Equation 4).

[0068] Furthermore, the terminal 10, base station 20, and core network 30 according to this embodiment may include predetermined information related to setting the PTW start position in the eDRX parameters, thereby enabling the PTW start position to be set more flexibly than in LTE. For example, the predetermined information related to setting the PTW start position may include information indicating the number of PTW start positions in the PH (the number of SFNs that can be set as the PTW start SFN), and the PTW start position may be determined by inputting the information indicating the number of PTW start positions in the PH into a predetermined formula. The predetermined formula may be Formula 5 and Formula 6 shown below. Furthermore, the PTW end position may be determined according to Formula 4, as in LTE.

[0069] (Equation 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 PH. For example, if NPTW=8, the possible values ​​of ieDRX are 0 to 7, so the PTW start position is one of the following eight values: SFN=0, 128, 256, 384, 512, 640, 768, and 896. Note that if 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 is possible to set the PTW start position more flexibly than in LTE.

[0070] When the start position of the PTW is determined according to equations 5 and 6 and the end position of the PTW is determined according to equation 4, the eDRX parameters include the eDRX cycle (TeDRX,H in equation 6), the time length of the PTW (L in equation 4), and the number of start positions of the PTW in PH (NPTW in equation 5).

[0071] Furthermore, in the wireless communication system 1 according to this embodiment, the predetermined information related to setting 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 the radio frame indicating the start position of the PTW may be information specifying a specific radio frame number, such as SFN=0 or SFN=64. Furthermore, the setting information related to eDRX may include information specifying a radio frame indicating the end position of the PTW (for example, SFN=64 or SFN=128). This makes it possible to flexibly set the end position of the PTW. In this case, the eDRX parameters include the eDRX cycle, information specifying the radio frame indicating the start position of the PTW, and information specifying the radio frame indicating the end position of the PTW.

[0072] <Example of specification change> 7 to 11 are diagrams showing examples of specification changes to the 3GPP specifications. The underlined parts in Figures 7 to 11 indicate specifications of information elements that store fields indicating eDRX parameters and values ​​that are set in the fields indicating eDRX parameters.

[0073] FIG. 7 shows an example of modified specifications for an RRC release message used when the base station 20 configures the terminal 10 with eDRX parameters for the inactive state. The eDRX parameters for the inactive state are stored in "Ran-PagingExtendedDRX-Info-r17" included in the information element "SuspendConfig." The "pagingExtendedDRX-Cycle-r17" field corresponds to the eDRX cycle, and the "pagingTimeWindow-r17" field corresponds to the PTW. If the information element "Ran-PagingExtendedDRX-Info-r17" exists but the "pagingExtendedDRX-Cycle-r17" and "pagingTimeWindow-r17" fields do not exist (absent), the terminal 10 recognizes that the eDRX parameters for the inactive state should be configured with the same values ​​as the eDRX parameters for the idle state. FIG. 8 shows an example of the specifications of the values ​​to be configured in the "pagingExtendedDRX-Cycle-r17" and "pagingTimeWindow-r17" fields.

[0074] FIG. 9 shows an example of modified specifications for an RRC setup request message transmitted by a terminal 10 that wishes to enable eDRX. The eDRX parameters for the inactive state are stored in the information element "Ran-PagingExtendedDRX-Info-r17." The "pagingExtendedDRX-Cycle-r17" field corresponds to the eDRX cycle, and the "pagingTimeWindow-r17" field corresponds to the PTW. If the information element "Ran-PagingExtendedDRX-Info-r17" exists but the "pagingExtendedDRX-Cycle-r17" and "pagingTimeWindow-r17" fields do not exist (absent), the base station 20 recognizes that the terminal 10 wishes to set the eDRX parameters for the inactive state to the same values ​​as the eDRX parameters for the idle state. Similarly, FIGS. 10 and 11 show modified specifications for an RRC setup complete message and an RRC reconfiguration complete message, respectively. 10 and 11, examples of the specifications of the values ​​set in the "pagingExtendedDRX-Cycle-r17" field and the "pagingTimeWindow-r17" field are the same as those in the lower part of FIG.

[0075] <Hardware configuration> 12 is a diagram showing an example of the hardware configuration of each device in the wireless communication system 1. Each device (e.g., terminal 10, base station 20, core network 30, etc.) in the wireless communication system 1 includes a processor 11, a storage device 12, a communication device 13 that performs wired or wireless communication, and an input device 14 that accepts various input operations and outputs various information.

[0076] The processor 11 is, for example, a CPU (Central Processing Unit) and controls each device in the wireless communication system 1. The processor 11 may execute various processes described in this embodiment by reading and executing a program from the storage device 12. Each device in the wireless communication system 1 may be configured with one or more processors 11. Furthermore, each device may be called a computer.

[0077] The storage device 12 is configured by, for example, storage such as a memory, a hard disk drive (HDD), and / or a solid state drive (SSD), etc. The storage device 12 may store various information necessary for the processor 11 to execute processing (for example, a program executed by the processor 11, etc.).

[0078] 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.

[0079] The RF device generates a radio signal to be transmitted from an antenna by, for example, performing D / A conversion, modulation, frequency conversion, power amplification, etc. on a digital baseband signal received from a BB device. 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 converts the digital baseband signal into a packet and converts the packet into a digital baseband signal.

[0080] 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.

[0081] 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. 12, or may include hardware not shown in Fig. 12. Furthermore, the hardware shown in Fig. 12 may be configured using one or more chips.

[0082] <Functional configuration> (Terminal) FIG. 13 is a diagram showing an example of the 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 part of the functions realized by the receiving unit 101 and the transmitting unit 102 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 101 and the transmitting unit 102 and the control unit 103 can be realized by the processor 11 executing a program stored in the storage device 12. The program can be stored in a storage medium. The storage medium storing the program may be a non-transitory computer-readable medium. The non-transitory storage medium is not particularly limited, and may be, for example, a storage medium such as a USB memory or a CD-ROM.

[0083] In the following description, eDRX parameters are an example of eDRX configuration values. Furthermore, an information element (e.g., Ran-PagingExtendedDRX-Info), an RRC message, and / or an NAS message including eDRX parameters for the inactive state are an example of first configuration information. The first configuration information may also be referred to as configuration information. Furthermore, an information element, an RRC message, and / or an NAS message including eDRX parameters for the idle state are an example of second configuration information. Furthermore, an information element, an RRC message, and / or an NAS message including eDRX parameters for the inactive state and / or the idle state transmitted from the terminal 10 are an example of request information.

[0084] 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 reception-related processing such as at least one of receiving, demapping, demodulating, decoding, monitoring, and measuring a radio signal.

[0085] Furthermore, the receiving unit 101 receives first setting information including an eDRX setting value for the inactive state. The receiving unit 101 may receive an RRC message including the first setting information from the base station 20. The RRC message may be, for example, an RRC release message, an RRC reconfiguration message, an RRC reestablishment message, an RRC resumption request message, an RRC resumption message, or an RRC setup message.

[0086] The receiving unit 101 may also receive a NAS message including the first setting information from the core network 30. The NAS message may be, for example, a registration response message, but is not limited to this. The receiving unit 101 may also receive second setting information including an eDRX setting value for the idle state.

[0087] The transmitter 102 transmits an uplink signal. The transmitter 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. The transmitter 102 also transmits request information including an eDRX setting value for the inactive state. The transmitter 102 may transmit an RRC message including the request information to the base station 20. The RRC message may be, for example, an RRC setup request message, an RRC reconfiguration complete message, an RRC re-establishment request message, an RRC re-establishment complete message, an RRC resumption request message, an RRC resumption complete message, or the like.

[0088] The transmitting unit 102 may transmit a NAS message including the request information to the core network 30. The NAS message may be, for example, a registration request message, but is not limited to this.

[0089] Furthermore, when transmitting unit 102 requests that the eDRX setting value for the deactive state be the same as the eDRX setting value for the RRC idle state, transmitting unit 102 may transmit request information indicating that the eDRX setting value for the deactive state is the same as the eDRX setting value for the idle state. For example, transmitting unit 102 may transmit request information that includes the eDRX setting value for the RRC idle state but does not include the eDRX setting value for the RRC deactive state in an NAS message. Furthermore, transmitting unit 102 may transmit an RRC message that includes information indicating that eDRX parameters for the deactive state are requested but does not include the eDRX setting value for the deactive state.

[0090] The control unit 103 performs various processes related to eDRX based on the eDRX setting value received by the receiving unit 101. Furthermore, in the RRC inactive state, the control unit 103 performs control so as to monitor control channel candidates (PDCCH candidates) in the paging search space during a PTW (reception period) in a PH (predetermined H-SFN) indicated by the eDRX setting value included in the first setting information.

[0091] In addition, when the first setting information does not include an eDRX setting value (e.g., an eDRX parameter for an inactive state), the control unit 103 may control the RRC inactive state to monitor control channel candidates within the paging search space during the reception period in a specified H-SFN indicated by the eDRX setting value included in the second setting information (e.g., an eDRX parameter for an idle state).

[0092] In addition, the eDRX setting value included in the first setting information includes information indicating the number of start positions of the reception period in a specified H-SFN, and the start position of the reception period may be determined by inputting information indicating the number of start positions of the reception period in a specified H-SFN (for example, information indicating the number of start positions of the PTW in a PH, NPTW) into a specified calculation formula.

[0093] (base station) FIG. 14 is a diagram showing an example of the 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 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.

[0094] 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 the RRC inactive state from the terminal 10.

[0095] The transmitter 202 transmits a downlink signal. The transmitter 202 may also transmit information and / or data transmitted via the downlink signal. The transmitter 202 also transmits, to the terminal 10, first configuration information including an eDRX configuration value for an RRC inactive state. The transmitter 202 also transmits, to the terminal 10, configuration information including an eDRX configuration value to be applied to the terminal 10 in the RRC inactive state.

[0096] The control unit 203 controls RAN paging processing for the terminal 10 in the RRC inactive state. Furthermore, the control unit 203 controls the terminal 10 in the RRC inactive state to transmit downlink control information (e.g., DCI) within the paging search space during the PTW (reception time period) in the PH (predetermined H-SFN) indicated by the eDRX setting value included in the first setting information.

[0097] <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.

[0098] Explicitly or implicitly including information indicating that the eDRX parameters for the inactive state have the same value as the eDRX parameters for the idle state may, for example, mean that each eDRX parameter for the inactive state includes a specific string or number, such as NULL.

[0099] "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)."

[0100] In the above embodiment, an example of the first time unit may be one hyperframe (10.23 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 unit 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 within the periodically repeated first time interval. PH may be set to a plurality of hyperframes from H-SFNs 0 to 1023.

[0101] The various signals, information, and parameters in the above embodiments may be signaled in any layer. That is, the various signals, information, and parameters may be replaced with signals, information, and parameters of any layer, such as an upper layer (e.g., NAS layer, RRC layer, MAC layer, etc.) or a lower layer (e.g., physical layer). Furthermore, notification of predetermined information is not limited to explicit notification, and may be implicit (e.g., by not notifying information or by using other information).

[0102] Furthermore, the names of various signals, information, parameters, IEs, channels, time units, and frequency units in the above embodiments are merely examples and may be replaced with other names. For example, a slot may be named in any way as long as it is a time unit having a predetermined number of symbols. Furthermore, an RB may be named in any way as long as it is a frequency unit having a predetermined number of subcarriers.

[0103] Furthermore, 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.).

[0104] Furthermore, the format of the various information is not limited to that of 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 interchangeable.

[0105] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0106] 1...wireless communication system, 10...terminal, 11...processor, 12...storage device, 13...communication device, 14...input / output device, 20...base station, 30...core network, 101...receiving unit, 102...transmitting unit, 103...control unit, 201...receiving unit, 202...transmitting unit, 203...control unit

Claims

1. a receiving unit that receives first information used to set a DRX (Discontinuous Reception) cycle from a core network device; A control unit that controls monitoring of PDCCH (Physical Downlink Control Channel) candidates within a paging search space at a paging occasion based on the DRX cycle; and The receiver receives, from a base station, second information used to indicate that a parameter for determining a position of a paging occasion for an RRC (Radio Resource Control) inactive state is the same value as a parameter for determining a position of a paging occasion for an RRC idle state; The control unit controls, when the RRC is inactive, to monitor the PDCCH candidates based on the DRX cycle set using the first information and the paging occasion indicated using the second information. Terminal.

2. The receiving unit receives a Non Access Stratum (NAS) message including the first information from the core network device. The terminal according to claim 1 .

3. The core network device is an Access and Mobility Management Function (AMF), The terminal according to claim 1 .

4. a receiving unit that receives first information used to set a DRX (Discontinuous Reception) cycle from a core network device; a transmitter that transmits downlink control information for paging to a terminal via a PDCCH (Physical Downlink Control Channel); a control unit that transmits the downlink control information within a paging search space at a paging occasion based on the DRX (Discontinuous Reception) cycle; and the transmitter transmits, to the terminal, second information used to indicate that a parameter for determining a position of a paging occasion for an RRC (Radio Resource Control) inactive state has the same value as a parameter for determining a position of a paging occasion for an RRC idle state; The control unit controls the terminal in the RRC inactive state to transmit the downlink control information based on the DRX cycle set using the first information and the paging occasion indicated using the second information. Base station.

5. receiving first information used to set a DRX (Discontinuous Reception) cycle from a core network device; Controlling monitoring of PDCCH (Physical Downlink Control Channel) candidates within a paging search space at a paging occasion based on the DRX cycle; receiving, from the base station, second information used to indicate that a parameter for determining a position of a paging occasion for an RRC (Radio Resource Control) inactive state is the same as a parameter for determining a position of a paging occasion for an RRC idle state; When the RRC is inactive, controlling to monitor the PDCCH candidates based on the DRX cycle set using the first information and the paging occasion indicated using the second information; A wireless communication method performed by a terminal, comprising:

6. The first information is included in a NAS (Non Access Stratum) message. The wireless communication method according to claim 5.

7. The core network device is an Access and Mobility Management Function (AMF), The wireless communication method according to claim 5.

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