Terminal and wireless communication method

Abstract

To allow an increase in the power consumption of a terminal to be reduced.SOLUTION: A terminal includes: a receiving unit that receives a first eDRX setting for an RRC idle state and a second eDRX setting for an RRC inactive state; and a control unit that sets at least part of setting information of the second eDRX setting to be the same as setting information of the first eDRX setting, and performs eDRX control in the RRC inactive state according to the second eDRX setting in which the part of the setting information is set to be the same as the setting information of the first eDRX setting.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The present disclosure relates to a terminal 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 (for example, Non-Patent Document 1).

[0003] Furthermore, in LTE (Long Term Evolution), taking into consideration the existence of terminals whose power consumption is further restricted, such as IoT (Internet of Things) devices, a technology called eDRX (extended DRX) has been introduced 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 started to study functions for new IoT terminals that use NR for radio access. The above-mentioned eDRX is also included in the functions under study. In addition, it is being considered that in NR, the eDRX setting may be different between the RRC idle state and the RRC inactive state.

[0006] Here, for some reason, the RRC state recognized by the terminal may not match the RRC state recognized by the network (base station and / or core network). In order to be able to receive radio signals even in such a case, the terminal may operate according to both the eDRX setting for the RRC idle state and the eDRX setting for the RRC inactive state. However, the terminal must receive radio signals according to both settings, which may increase the power consumption of the terminal.

[0007] The present disclosure has been made in consideration of the above circumstances, and one of its objects is to provide a terminal and a wireless communication method that make it possible to reduce an increase in power consumption of the terminal. [Means for solving the problem]

[0008] A terminal according to one embodiment of the present disclosure has a receiving unit that receives a first eDRX setting for an RRC idle state and a second eDRX setting for an RRC inactive state, and a control unit that sets at least a portion of the setting information of the second eDRX setting to be identical to the setting information of the first eDRX setting, and performs eDRX control in the RRC inactive state in accordance with the second eDRX setting in which at least a portion of the setting information is set to be identical to the setting information of the first eDRX setting. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a terminal and a wireless communication method that make it possible to reduce an increase in power consumption of the terminal. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of an overview of a wireless communication system according to this embodiment. [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. [Figure 4] FIG. 4 is a diagram for explaining the eDRX operation. [Diagram 5] FIG. 5 is a diagram showing a pattern in which a PTW in an inactive state and a PTW in an idle state overlap. [Figure 6] FIG. 6 is a diagram showing a pattern in which the PTW in the inactive state and the PTW in the idle state do not overlap. [Figure 7] FIG. 7 is a diagram illustrating an example of a processing procedure when eDRX parameters for the idle state are set in a terminal from a core network. [Figure 8] FIG. 8 is a diagram illustrating an example of a processing procedure when eDRX parameters for the inactive state are set in a terminal from a base station. [Figure 9] FIG. 9 is a flowchart illustrating eDRX operation in an inactive state. [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 illustrating an example of a hardware configuration of each device in a wireless communication system. [Figure 17] FIG. 17 is a diagram illustrating an example of a functional configuration of a terminal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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.

[0012] 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.

[0013] The radio access technology (Radio Access Technology: RAT) of the wireless communication system 1 is assumed to be, for example, NR, but is not limited thereto, and various RATs such as LTE, LTE-Advanced, or sixth generation or later RATs can be used.

[0014] The terminal 10 is a specific 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 be called a user equipment (UE), a mobile station (MS), a terminal (User Terminal), a radio apparatus, a subscriber terminal, an access terminal, etc. The terminal 10 may be of a mobile type or a fixed type. The terminal 10 is configured to be capable of communicating using, for example, NR as a RAT.

[0015] 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, wearable devices, etc.

[0016] The RedCap terminal is assumed to have higher performance than terminals for low power wide area (LPWA), and the carrier used by the RedCap terminal may have a bandwidth of, for example, 20 MHz, 50 MHz, or 100 MHz. The maximum terminal bandwidth (maximum UE bandwidth) supported by the RedCap terminal may be, for example, 20 MHz for Frequency Range 1 (for example, a frequency band of 6 GHz or less) and 100 MHz for Frequency Range 2 (for example, a frequency band higher than 6 GHz). LPWA includes, for example, Category 1, Long Term Evolution for Machine-type-communication (LTE-M) and Narrow Band IoT (NB-IoT) that operate on the LTE RAT. The maximum bandwidth of Category 1 is 20 MHz, the maximum bandwidth of LTE-M is 1.4 MHz (6RB), and the maximum bandwidth of NB-IoT is 180 kHz (1RB). In this way, the RedCap terminal is expected to be used as a middle-range terminal between eMBB, URLLC, and LPWA. The terminal 10 according to the present embodiment includes a RedCap terminal and a terminal for LPWA.

[0017] 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), an 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 one 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).

[0018] 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).

[0019] The core network device includes at least one of a plurality of functions, such as an Access and Mobility Management Function (AMF) that manages information related to access and mobility management, a Session Management Function (SMF) that performs session management, a User Plane Function (UPF) that controls transmission of the U-plane, and a Network Slice Selection Function (NSSF) that manages network slices. Each of these functions is implemented in one or more physical or logical devices.

[0020] 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.

[0021] <UE state> Next, the RRC state of the terminal 10 defined in NR will be described. The RRC state of the terminal 10 includes the RRC idle state (hereinafter referred to as the "idle state"), the RRC inactive state (hereinafter referred to as the "inactive state"), and the RRC connected state (hereinafter referred to as the "connected state").

[0022] 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.

[0023] The terminal 10 in the idle state camps on the cell C selected by cell selection and / or cell reselection (hereinafter referred to as "cell selection / reselection") and receives the system information broadcast in the cell C. When the RRC connection of the terminal 10 in the idle state is established, it transitions to the connected state.

[0024] 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. 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 an RRC context and a NAS context.

[0025] The core network 30 manages the location of the terminal 10 in units called TAs (Tracking Areas), and instructs the base stations 20 constituting the TA in which the terminal 10 to be called is located to transmit a paging signal. In addition, the one or more base stations 20 that receive the instruction simultaneously transmit the paging signal.

[0026] In addition, in NR, a RAN notification area (RNA) that is an area obtained by subdividing a TA (Tracking Area) is newly defined, and the base station 20 manages the RAN notification area in which the terminal 10 in the connected state and the inactive state exists. In addition, in NR, a technology called "RAN paging" is introduced that performs paging processing in units of RAN notification areas, which is used when calling a terminal 10 in the inactive state. In RAN paging, a paging signal is transmitted simultaneously from a plurality of base stations 20 that constitute a RAN notification area in which the terminal 10 in the inactive state exists. The terminal 10 in the inactive state that receives the paging signal resumes the RRC connection and transitions to the connected state. In the following description, the process of transmitting a paging signal in units of TAs at the instruction of the core network 30 is referred to as "CN paging" to distinguish it from "RAN paging". In addition, when there is no distinction between CN paging and RAN paging, it is referred to as "paging".

[0027] The connected state is a 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 non-active state.

[0028] <eDRX technology> Next, the eDRX (extended DRX) technology according to this embodiment will be described. In NR, a slot with a variable length of time, a subframe with a time length of 1 ms, a radio frame with a time length of 10 ms, and a hyperframe with a time length of 10.23 seconds are defined. 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.

[0029] Fig. 3 is a diagram for explaining the DRX operation. As shown in Fig. 3, a terminal 10 in an idle state or an inactive 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. The terminal 10 that receives a paging signal within the PO period establishes communication with the base station 20 and transitions to a connected state. The DRX cycle is a maximum of 2.56 seconds.

[0030] Fig. 4 is a diagram for explaining eDRX operation. As shown in Fig. 4, a terminal 10 in an idle state or an inactive 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 within a hyperframe called a PH (Paging Hyperframe). One PH may exist for each eDRX cycle.

[0031] 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.

[0032] Here, PH may be H-SFN that satisfies the following formula 1.

[0033] (Formula 1) H-SFN mod T eDRX,H = (UE_ID_H mod T eDRX,H ) "T eDRX,H" indicates an eDRX cycle and is set to an integer multiple of a hyperframe. UE_ID_H may be the most significant 10 or 12 bits of a hashed ID defined based on 5G-S-TMIS (5G S-Temporary Mobile Subscriber Identity).

[0034] 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.

[0035] (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.

[0036] (Formula 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 using a message of an upper layer (NAS (Non Access Stratum)), an RRC message, broadcast information, or the like.

[0037] In the following description, "eDRX parameters" may mean only parameters that determine eDRX operation, such as the eDRX cycle and the length of the PTW, or may include parameters that determine DRX operation, such as the DRX cycle and PO position settings, in addition to parameters that determine eDRX operation.

[0038] In addition, in this embodiment, the "eDRX parameters for inactive state" refer to the eDRX parameters applied to the terminal 10 in the inactive state. Moreover, the "eDRX parameters for idle state" refer to the eDRX parameters applied to the terminal 10 in the idle state.

[0039] Also, in this embodiment, the eDRX parameters for the idle state and the eDRX parameters for the inactive state may be different.

[0040] <Challenges in achieving eDRX in both idle and inactive states> The RRC state of the terminal 10 is managed by both the terminal 10 and the network (the base station 20 and / or the core network 30). Normally, the RRC state managed by the terminal 10 and the RRC state managed by the network match, but for some reason, such as when the UE context (RRC context) is lost due to a software abnormality in the base station 20, the RRC state of the terminal 10 may become inconsistent between the terminal 10 and the network.

[0041] Therefore, taking into consideration the possibility of such a mismatch state, in order to receive paging signals without omission, it is considered desirable for the terminal 10 to perform eDRX operation in accordance with both the eDRX parameters for the idle state and the eDRX parameters for the inactive state, regardless of whether the terminal 10 recognizes itself as being in the idle state or the inactive state.

[0042] FIG. 5 is a diagram showing a pattern in which the PTW in the inactive state overlaps with the PTW in the idle state. The upper part of FIG. 5 shows the eDRX operation in the inactive state, and the lower part of FIG. 5 shows the eDRX operation in the idle state. In the example of FIG. 5, the PH in the inactive state and the PH in the idle state overlap in the fifth H-SFN. Furthermore, a part of the PTW in the idle state overlaps with the PTW in the inactive state. In this case, the terminal 10 starts the receiving circuit in the fifth H-SFN according to the eDRX parameters for the idle state to monitor the downlink control channel candidates, and stops the receiving circuit when the PTW in the idle state ends.

[0043] FIG. 6 is a diagram showing a pattern in which the PTW in the inactive state and the PTW in the idle state do not overlap. The upper part of FIG. 6 shows the eDRX operation in the inactive state, and the lower part of FIG. 6 shows the eDRX operation in the idle state. In the example of FIG. 6, the PH in the inactive state and the PH in the idle state overlap in the fifth H-SFN. On the other hand, unlike FIG. 5, the PTW in the idle state and the PTW in the inactive state do not overlap. In this case, the terminal 10 performs the following operations in the fifth H-SFN: start the receiving circuit according to the PTW in the idle state to monitor the downlink control channel candidate, stop the receiving circuit when the TW ends, start the receiving circuit according to the PTW in the inactive state to monitor the downlink control channel candidate, and stop the receiving circuit when the PTW ends. That is, the process of starting the receiving circuit is performed twice in the same H-SFN.

[0044] In this way, when a PH in an inactive state overlaps with a PH in an idle state, and the PTW in an inactive state and the PTW in an idle state do not overlap in the PH, the terminal 10 itself needs to start up its own receiving circuit twice in the overlapping PH, which may result in increased power consumption by the terminal 10.

[0045] Therefore, in this embodiment, when the terminal 10 transitions to the inactive state, the start position of the PTW in the idle state or the start position of the PTW in the inactive state is made the same (aligned) as the start position of the PTW in the other state. This makes it possible to reduce the increase in power consumption of the terminal 10 because the process of starting the receiving circuit in the same H-SFN is performed only once.

[0046] <Configuring eDRX parameters for idle and inactive states> 7 is a diagram showing an example of a processing procedure when eDRX parameters for the idle state are set in the terminal 10 from the core network 30. Note that the core network 30 is assumed to be, for example, an AMF, but is not limited thereto.

[0047] In step S100, the terminal 10 desiring to enable eDRX transmits a registration request message including "eDRX parameters" indicating the eDRX operation to be set to the core network 30. In step S101, the core network 30 determines eDRX parameters for idle state based on the registration request received from the terminal 10. In step S102, the core network 30 transmits a NAS message (more specifically, a registration accept message) including the determined eDRX parameters for idle state to the terminal 10 in order to set the determined eDRX parameters in the terminal 10. In step S103, the terminal 10 sets the eDRX parameters for idle state included in the NAS message (i.e., stores the eDRX parameters for idle state in a storage device).

[0048] FIG. 8 is a diagram showing an example of a processing procedure when eDRX parameters for the inactive state are set in the terminal 10 from the base station 20.

[0049] In step S200, the core network 30 transmits, for example, an N2 message including information indicating that the terminal 10 desires to activate eDRX to the base station 20. The N2 message includes Core Network Assistance Information for RRC INACTIVE, and the core network assist information may include information indicating that the terminal 10 desires to activate eDRX.

[0050] In step S201, the base station 20 determines eDRX parameters for the deactivation state to be set in the terminal 10. In step S202, when instructing the terminal 10 to transition to the deactivation state, the base station 20 transmits an RRC Release message including the eDRX parameters for the deactivation state determined in step S201 in a suspend configuration (SuspendConfig) to the terminal 10. In step S203, the terminal 10 sets the eDRX parameters for the deactivation state included in the RRC release message (stores the eDRX parameters in a storage device).

[0051] Note that the eDRX parameters in the inactive state may be set in the terminal 10 by using a NAS message from the core network 30, using the processing procedure shown in Fig. 7. In this case, the processing procedure shown in Fig. 8 is omitted.

[0052] <eDRX operation in inactive state> Fig. 9 is a flowchart for explaining eDRX operation in the inactive state. In the processing procedure of Fig. 9, it is assumed that eDRX parameters for the idle state are set in the terminal 10.

[0053] In step S300, the terminal 10 transitions to the inactive state when it receives an RRC Release message including a temporary suspension setting (SuspendConfig) instructing the terminal 10 to transition from the active state to the inactive state from the base station 20. Here, the temporary suspension setting includes eDRX parameters for the inactive state, and the terminal 10 sets the received eDRX parameters for the inactive state.

[0054] In step S301, the terminal 10 determines whether or not a "specific flag" is set in the RRC Release message received in the processing procedure of step S300. More specifically, the terminal 10 may determine whether or not a "specific flag" is present in eDRX parameters for a deactivated state included in the RRC Release Message received in the processing procedure of step S300.

[0055] Here, the "specific flag" may be defined as an information element that, when a PTW in an idle state and a PTW in an inactive state overlap, instructs that the start position of either PTW (or the PTW in the inactive state) be made the same (aligned) as the start position of the other PTW (or the PTW in the idle state). If a specific flag is set in the terminal 10, proceed to step S302, and if a specific flag is not set in the terminal 10, proceed to the processing procedure of step S304.

[0056] In step S302, the terminal 10 sets the start position of the PTW in the inactive state for a PH in which the PTW in the idle state overlaps with the PTW in the inactive state to be the same as the start position of the PTW in the idle state. A specific example of the specific flag and a processing procedure in the case where the specific flag exists will be described later. Here, the PH in which the PTW in the idle state overlaps with the PTW in the inactive state specifically means any one of the following: an H-SFN that corresponds to both a PH in the idle state and a PH in the inactive state (i.e., an H-SFN in which the eDRX cycle for the idle state and the eDRX cycle for the inactive state match), and a part of the PTW in the idle state in the H-SFN includes a PTW in the inactive state (e.g., corresponds to the example of FIG. 5), a part of the PTW in the idle state overlaps with a part of the PTW in the inactive state, or a part of the PTW in the inactive state includes a PTW in the idle state.

[0057] In step S303, the terminal 10 performs eDRX control according to the eDRX parameters for the idle state and the eDRX parameters for the inactive state in which the PTW start position is set to the same as that in the idle state. That is, the terminal 10 monitors downlink control channel candidates in SFNs included in either the "PTW start position and PTW end position in the idle state" or the "PTW start position and PTW end position in the inactive state in which the PTW start position is set to the same as that in the idle state."

[0058] In step S304, the terminal 10 performs eDRX control according to both the eDRX parameters for the idle state and the eDRX parameters for the inactive state, without setting the start position of the PTW in the inactive state to be the same as the start position of the PTW in the idle state. That is, the terminal 10 monitors downlink control channel candidates in the H-SFN corresponding to the PH in the idle state according to the PTW start position and the PTW end position in the idle state. Also, the terminal 10 monitors downlink control channel candidates in the H-SFN corresponding to the PH in the inactive state according to the PTW start position and the PTW end position in the inactive state. Also, the terminal 10 does not monitor downlink control channel candidates in the H-SFN that does not correspond to either the PH in the idle state or the PH in the inactive state.

[0059] <Processing when a specific flag is set> (Pattern 1) In the case of pattern 1, it is assumed that the PTW in the idle state and the PTW in the inactive state are calculated using formulas 1 to 4.

[0060] When the “specific flag” related to the pattern 1 is set in the RRC release message, the terminal 10 calculates “T eDRX,H " is substituted with the eDRX cycle included in the eDRX parameters for the idle state instead of the eDRX cycle included in the eDRX parameters for the inactive state, thereby calculating the start position of the PTW in the inactive state. In addition, according to Equation 4, the end position of the PTW in the inactive state is calculated by adding the time length of the PTW included in the eDRX parameters for the inactive state to the calculated start position of the PTW.

[0061] The terminal 10 monitors downlink control channel candidates at SFNs where at least one of the PTWs is set according to the PTW in the idle state and the PTW in the inactive state. For example, assume that the PTW start position in the idle state is SFN=0 and the PTW end position is SFN=299 (i.e., the PTW time length=3 seconds). Also assume that the PTW start position in the inactive state is SFN=0 and the PTW end position is SFN=99 (i.e., the PTW time length=1 second). In this case, the terminal 10 monitors downlink control channel candidates at POs that exist between SFN=0 and SFN=299.

[0062] In pattern 1, the "specific flag" may be expressed as "information indicating that the start position of the PTW in the inactive state is the same as the start position of the PTW in the idle state." The information may be an information element in an RRC message.

[0063] As a result, the start position of the PTW in the inactive state coincides with the start position of the PTW in the idle state. Therefore, when the PH in the inactive state and the PH in the idle state overlap, the terminal 10 can receive the paging signal by simply activating the receiving circuit of the terminal 10 itself once.

[0064] Fig. 10 shows an example of a change in the specifications of TS38.304 in pattern 1. Figs. 11 and 12 show an example of a change in the specifications of TS38.331 in pattern 1. "pagingTimeWindowStart-r17" shown in Fig. 11 may be expressed as "information indicating whether or not the start position of a PTW in an inactive state is made the same as the start position of a PTW in an idle state." Also, in Fig. 11, the "specific flag" may correspond to an information element "pagingTimeWindowStart-r17" whose parameter value is set to "sameAsIdle." Note that when the value of "pagingTimeWindowStart-r17" is set to "differentFromIdle," the terminal 10 does not perform processing to change the start position of a PTW in an inactive state.

[0065] (Pattern 2) In the case of pattern 2, it is assumed that the PTW in the idle state is calculated using formulas 1 to 4. On the other hand, the PTW in the inactive state is calculated using formula 5 shown below instead of formula 2. In other words, the PTW in the inactive state is calculated using formulas 1 and 3 to 5.

[0066] (Formula 5) SFN = 256 * (ieDRX for RRC_IDLE + offset) ieDRX for RRC_IDLE is a value obtained by substituting the eDRX cycle in the idle state into Equation 3. Furthermore, offset is a value specified by a specific flag, and may be any one of 0 to 3, for example. The ieDRX in the idle state calculated by Equation 3 may be any one of 0 to 3. If the SFN calculated by Equation 5 exceeds 1023, the terminal 10 may consider the value obtained by subtracting 1024 from the calculated value as the SFN. For example, if the calculation result of Equation 5 is 1536 (256×6), the terminal 10 may consider SFN=512 (1536−1024).

[0067] In pattern 2, the specific flag may be set when "information indicating that a start position shifted by an offset value from the start position of a PTW in an idle state is set as the start position of a PTW in an inactive state is set in the terminal 10, and the offset value is set to 0." The information may be an information element in an RRC message. For example, the information element may be called PagingTimeWindowOffset.

[0068] When the “specific flag” related to pattern 2 is set in the RRC release message, the terminal 10 sets the offset in Equation 5 to zero. That is, the start position of the PTW in the inactive state becomes the same as the start position of the PTW in the idle state.

[0069] As in pattern 1, the terminal 10 monitors downlink control channel candidates in an SFN in which at least one of the PTWs in the idle state and the PTW in the inactive state is set, according to the PTW in the idle state and the PTW in the inactive state.

[0070] As a result, the start position of the PTW in the inactive state coincides with the start position of the PTW in the idle state. Therefore, when the PH in the inactive state and the PH in the idle state overlap, the terminal 10 can receive the paging signal by simply activating the receiving circuit of the terminal 10 itself once.

[0071] Fig. 13 shows an example of a change in the specifications of TS38.304 in Pattern 2. Figs. 14 and 15 show an example of a change in the specifications of TS38.331 in Pattern 2. "pagingTimeWindowOffset-r17" shown in Fig. 14 is information indicating that the start position of the PTW in the inactive state is set to a start position shifted by an offset value from the start position of the PTW in the idle state. In Fig. 14, the "specific flag" may correspond to the information element "pagingTimeWindowOffset-r17" with the parameter value set to "0".

[0072] <Modification> The eDRX parameters for the inactive state are not limited to an RRC release message and may be configured in the terminal 10 using another message. The other message may be, for example, an RRC reconfiguration message, an RRC reestablishment message, an RRC resumption request (RRCResumeRequest / RRCResumeRequest1) message, an RRC resumption (RRCResume) message, an RRC setup message, or broadcast information (system information, SIB1, SIB2, etc.).

[0073] The specific flag may be part of the eDRX parameters for the inactive state, or may be defined as information separate from the eDRX parameters for the inactive state.

[0074] When the specific flag is defined as information separate from the eDRX parameters for the inactive state, the eDRX parameters for the inactive state and the specific flag may be set in the terminal 10 using different messages, respectively. For example, the eDRX parameters for the inactive state may be set in the terminal 10 using an RRC release message, and the specific flag may be set in the terminal 10 using an RRC reconfiguration message, an RRC re-establishment message, an RRC resume request message, an RRC resume message, an RRC setup message, or broadcast information (system information, SIB1, SIB2, etc.), etc.

[0075] In pattern 1, when a specific flag is set in terminal 10, when terminal 10 calculates the end position of the PTW using formula 4, it may calculate the end position of the PTW in the inactive state by substituting the time length of the PTW in the idle state into formula 4.

[0076] In the processing procedure described in the pattern 1, instead of changing the eDRX parameters for the inactive state to the eDRX parameters for the idle state, the eDRX parameters for the idle state may be changed to the eDRX parameters for the inactive state. For example, when the "specific flag" related to the pattern 1 is set in the RRC release message, the terminal 10 changes "T eDRX,H The start position of the PTW in the idle state may be calculated by substituting the eDRX cycle included in the eDRX parameters for the inactive state into " " instead of the eDRX cycle included in the eDRX parameters for the idle state. Also, the end position of the PTW in the idle state may be calculated by adding the time length of the PTW included in the eDRX parameters for the idle state to the calculated start position of the PTW in the idle state according to Equation 4. In this case, the "specific flag" may be defined as an information element that instructs that the start position of the PTW in the idle state be made the same (aligned) as the start position of the PTW in the inactive state when the PTW in the idle state and the PTW in the inactive state overlap.

[0077] In the processing procedure described in Pattern 2, the eDRX parameters for the idle state may be calculated by adding an offset to the eDRX parameters for the idle state, rather than calculating the eDRX parameters for the deactive state by adding an offset to the eDRX parameters for the deactive state. For example, when the "specific flag" related to Pattern 1 is set in the RRC release message, the terminal 10 may calculate the PTW in the deactive state using Formulas 1 to 4, and calculate the PTW in the idle state using Formulas 1, 3 to 5.

[0078] Regardless of whether the PH where the PTW in the idle state overlaps with the PTW in the non - active state or not, in all PHs, the start position of either one of the PTWs may be made the same as (aligned with) the start position of the other PTW. For example, the start position of each PTW in the non - active state may be set to be the same as the start position of the PTW in the idle state. In this case, in the processing procedure of step S302, the terminal 10 may set the start position of the PTW in the non - active state to be the same as the start position of the PTW in the idle state for each PH corresponding to the non - active state. In this case, the "specific flag" may be meant to be an information element that instructs to make the start position of either one of the PTWs the same as (aligned with) the start position of the other PTW. Also, the "specific flag" may be defined as an information element that instructs to make the start position of the PTW in the non - active state (or idle state) the same as (aligned with) the start position of the PTW in the idle state (or non - active state) when the PTW in the idle state overlaps with the PTW in the non - active state.

[0079] In the processing procedure described in Pattern 1, the terminal 10 may further calculate the end position of the PTW in the non - active state by adding the time length of the PTW included in the eDRX parameter for the idle state to the calculated start position of the PTW according to Equation 4. That is, in addition to the eDRX cycle, the time length of the PTW may also be made the same as the eDRX parameter for the idle state. In other words, the terminal 10 may make the start position and end position of the PTW in the non - active state coincide with the start position and end position of the PTW in the idle state.

[0080] <Modified Example of eDRX Parameter> 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 for the idle state and / or the eDRX parameters for the inactive state, thereby enabling the start position of the PTW to be flexibly set. 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). 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 Equation 6 and Equation 7 instead of Equation 2 and Equation 3. The end position of the PTW may be determined according to Equation 4.

[0081] (Formula 6) SFN = (1024 div N PTW )*ieDRX (Formula 7) ieDRX=floor(UE_ID_H / TeDRX,H) mod N PTW In formulas 6 and 7, N PTW is information indicating the number of start positions of PTW in PH. For example, N PTW If N = 8, the possible values ​​of ieDRX are 0 to 7, so the start position of the PTW is one of the following eight values: SFN = 0, 128, 256, 384, 512, 640, 768, 896. PTW When x = 4, Equations 6 and 7 are the same as Equations 2 and 3, respectively. In other words, by using Equations 6 and 7, it is possible to flexibly set the start position of the PTW.

[0082] When the start position of the PTW is determined according to Equations 6 and 7 and the end position of the PTW is determined according to Equation 4, the eDRX parameters include the eDRX cycle (TeDRX,H in Equation 7), the time length of the PTW (L in Equation 4), and the number of start positions of the PTW in PH (N in Equation 6). PTW ) are included.

[0083] Furthermore, 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 the 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. Furthermore, the eDRX parameters may include information specifying a radio frame indicating the end position of the PTW (for example, SFN=64, SFN=128, etc.). This makes it possible to flexibly set the end position of the PTW. In this case, the eDRX parameters include an 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.

[0084] <Hardware configuration> 16 is a diagram showing an example of a hardware configuration of each device in a wireless communication system. Each device (e.g., a terminal 10, a base station 20, a 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 that accepts various input operations and an input / output device 14 that outputs various information.

[0085] 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.

[0086] 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.).

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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. 16, or may include hardware not shown in Fig. 16. Furthermore, the hardware shown in Fig. 16 may be configured by one or more chips.

[0091] <Functional configuration> (Terminal) FIG. 17 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.

[0092] The eDRX parameters and specific flags used in the above description are examples of eDRX settings and specified information, respectively, in the following description.

[0093] 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.

[0094] Moreover, the receiving unit 101 receives an eDRX setting for an idle state (hereinafter referred to as a "first eDRX setting") and an eDRX setting for an inactive state (hereinafter referred to as a "second eDRX setting"). The receiving unit 101 may receive a NAS message including the first eDRX setting from the core network 30. The receiving unit 101 may receive an RRC message or broadcast information including the second eDRX setting 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 resume request message, an RRC resume message, an RRC setup message, or the like. The receiving unit 101 may receive a NAS message including the second eDRX setting from the core network 30.

[0095] 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.

[0096] The control unit 103 performs various processes related to eDRX based on the eDRX setting 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 PTW (reception period) in a PH (predetermined H-SFN) indicated in the first eDRX setting in an idle state. 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 PTW (reception period) in a PH (predetermined H-SFN) indicated in the second eDRX setting in an inactive state.

[0097] Furthermore, the control unit 103 sets at least a part of the setting information of the second eDRX setting to be the same as the setting information of the first eDRX setting, and performs eDRX control in the inactive state according to the second eDRX setting in which the part of the setting information is set to be the same as the setting information of the first eDRX setting. At least a part of the setting information of the second eDRX setting may be an eDRX cycle of the eDRX setting in the inactive state. The "second eDRX setting in which the part of the setting information is set to be the same as the setting information of the first eDRX setting" may be referred to as a "third eDRX setting" for convenience in order to distinguish it from the second eDRX setting received by the receiving unit 101.

[0098] Furthermore, the control unit 103 may set the setting information of the second eDRX setting to be the same as the setting information of the first eDRX setting, and perform eDRX control in the inactive state according to the second eDRX setting in which the setting information is set to be the same as the setting information of the first eDRX setting. The setting information of the second eDRX setting may be the eDRX cycle and the time length of the PTW of the eDRX setting in the inactive state (corresponding to a modified example).

[0099] Furthermore, when the second eDRX setting includes predetermined information, the control unit 103 may set at least a part of the setting information of the second eDRX setting to be the same as the setting information of the first eDRX setting (corresponding to S302-YES and S303 in FIG. 9). Here, the predetermined information may be a specific flag in the above-mentioned pattern 1 and pattern 2. For example, in pattern 1, it may be "pagingTimeWindowStart-r17" with the parameter value set to True, and in pattern 2, it may be "pagingTimeWindowOffset-r17" with the parameter value (offset) set to zero.

[0100] In addition, when the second eDRX setting does not include specified information, the control unit 103 may perform eDRX control in the RRC inactive state according to the second eDRX setting, without setting at least a part of the setting information of the second eDRX setting to be identical to the setting information of the first eDRX setting (corresponding to S305 in Figure 9).

[0101] In addition, when a PTW (first reception period) for monitoring control channel candidates indicated by the first eDRX setting overlaps with a PTW (second reception period) for monitoring control channel candidates indicated by the second eDRX setting, the control unit 103 may perform eDRX control in the RRC inactive state according to a "second eDRX setting in which at least some of the setting information of the second eDRX setting is set to be the same as the setting information of the first eDRX setting."

[0102] In addition, when the PTW (first reception period) for monitoring control channel candidates indicated by the first eDRX setting and the PTW (second reception period) for monitoring control channel candidates indicated by the second eDRX setting do not overlap, the control unit 103 may perform eDRX control in the RRC inactive state in accordance with the second eDRX setting set in the terminal 10 (i.e., without setting at least some of the setting information of the second eDRX setting to be the same as the setting information of the first eDRX setting).

[0103] In addition, at least a part of the setting information of the second eDRX setting is an eDRX period (information used to calculate the start position of the second reception period), and the setting information of the first eDRX setting may be an eDRX period (information used to calculate the start position of the first reception period).

[0104] Furthermore, the control unit 103 may change (or replace) the eDRX cycle in the second eDRX setting with the eDRX cycle in the first eDRX setting. Furthermore, the "second eDRX setting in which some setting information is set to be the same as the setting information in the first eDRX setting" may be expressed as the "changed second eDRX setting" (corresponding to pattern 1).

[0105] Furthermore, the control unit 103 may determine the eDRX cycle in the second eDRX setting by adding an offset value included in the second eDRX setting to the eDRX cycle in the first eDRX setting. The offset value may be zero (corresponding to pattern 2).

[0106] <Supplementary Information> eDRX may also be referred to as discontinuous reception, extended discontinuous reception, receiving interval control, extended receiving interval control, etc.

[0107] "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)."

[0108] 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 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.

[0109] 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).

[0110] 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 any name as long as it is a time unit having a predetermined number of symbols. Also, an RB may be any name as long as it is a frequency unit having a predetermined number of subcarriers.

[0111] 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.).

[0112] 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.

[0113] 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. [Explanation of symbols]

[0114] 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. Receive a NAS message from a core network, the NAS message including first information for setting an eDRX cycle; A receiving unit that receives an RRC message from a base station, the RRC message including second information for setting an eDRX cycle and third information for setting a PTW length; determining an H-SFN of a PH by substituting the eDRX cycle based on the second information into a first equation; A control unit that monitors physical downlink control channel candidates at paging occasions during a PTW period of the PH, The control unit determines a start position of the PTW by substituting the eDRX cycle based on the first information into a second formula, and determines an end position of the PTW by substituting the length of the PTW based on the third information into a third formula. Terminal device.

2. The receiving unit receives a NAS message including fourth information for setting a length of a PTW from a core network; The control unit is The H-SFN of the PH is determined by substituting the eDRX cycle based on the first information into the first formula, the start position of the PTW of the PH is determined by substituting the eDRX cycle based on the first information into the second formula, and the end position is determined by substituting the length of the PTW based on the fourth information into the third formula. The terminal device according to claim 1 .

3. The terminal device is in an RRC inactive state. The terminal device according to claim 1 or 2.

4. receiving a NAS message from a core network, the NAS message including first information for setting an eDRX cycle; receiving an RRC message from a base station, the RRC message including second information for setting an eDRX cycle and third information for setting a PTW length; determining an H-SFN of a PH by substituting the eDRX cycle based on the second information into a first formula; Determining a start position for the PTW of the PH by substituting the eDRX cycle based on the first information into a second formula; determining an end position by substituting the length of the PTW based on the third information into a third formula; monitoring physical downlink control channel candidates at paging occasions during the PTW; A communication method for a terminal device.

5. receiving a NAS message from a core network, the NAS message including fourth information for setting a length of the PTW; determining an H-SFN of a PH by substituting the eDRX cycle based on the first information into the first formula; Determining the start position for the PTW of the PH by substituting the eDRX cycle based on the first information into the second formula; and determining the end position by substituting the length of the PTW based on the fourth information into the third formula. A communication method for a terminal device according to claim 4.

6. The terminal device is in an RRC inactive state. A communication method for a terminal device according to claim 4 or 5.

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