Terminal, base station and wireless communication method

Abstract

To provide a terminal in which more flexible operation settings related to eDRX can be performed, a base station and a radio communication method.SOLUTION: A terminal is provided, having: a reception unit that receives setting information on eDRX; and a control unit performing control in such a manner that a control channel candidate within a paging search space is monitored in a reception period in a predetermined H-SFN indicated by the setting information on eDRX. The setting information includes predetermined information on the setting of a start position of the reception period in the predetermined H-SFN.SELECTED DRAWING: Figure 5

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 devices that use NR for wireless access, including the eDRX mentioned above.

[0006] NR is designed to allow more flexible configuration of wireless communication than LTE, so when implementing eDRX in NR, it is considered desirable to enable more flexible configuration than LTE.

[0007] The present disclosure has been made in consideration of the above circumstances, and one of its objectives is to provide a terminal, a base station, and a wireless communication method that enable more flexible operation settings related to eDRX. [Means for solving the problem]

[0008] A terminal according to one embodiment of the present disclosure has a receiving unit that receives configuration information regarding eDRX, and a control unit that controls monitoring of control channel candidates within a paging search space during a reception period in a specified H-SFN indicated by the configuration information regarding eDRX, and the configuration information includes specified information regarding setting of a start position of the reception period in the specified H-SFN. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, it is possible to provide a terminal, a base station, and a wireless communication method that enable more flexible operation settings related to eDRX. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an example of a wireless communication system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram for explaining a DRX operation during paging. [Figure 3] FIG. 10 is a diagram for explaining eDRX operation during paging. [Figure 4]FIG. 2 is a diagram illustrating an example of the hardware configuration of each device in the wireless communication system. [Figure 5] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal. [Figure 6] FIG. 2 is a diagram illustrating an example of a functional configuration of a base station. [Figure 7] FIG. 10 is a sequence diagram showing an example of a processing procedure related to eDRX. [Figure 8] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. [Figure 9] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. [Figure 10] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. [Figure 11] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. [Figure 12] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. [Figure 13] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. [Figure 14] FIG. 1 is a diagram illustrating an example of specification changes in the 3GPP specifications. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described with reference to the accompanying drawings, in which the same reference numerals denote the same or similar configurations.

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

[0013] The 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.

[0014] 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.

[0015] 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 cameras, wearable devices, etc.

[0016] 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.

[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 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).

[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 U-plane transmission, 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, a terminal 10 receives a downlink (DL) signal and / or transmits an uplink (UL) signal from a base station 20. One or more carriers may be configured in 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 in one carrier. One BWP has at least a portion of the bandwidth of the carrier.

[0021] In the following description, a physical downlink control channel (PDCCH) will be described as an example of a downlink control channel, but the downlink control channel may be any channel used to transmit downlink control information (Downlink Control Channel: DCI), and its name is not limited to PDCCH. Furthermore, the downlink control information may be DCI (Downlink Control Information) in a predetermined format in which a cyclic redundancy check (CRC) is scrambled using a predetermined Radio Network Temporary Identifier (RNTI), and its name is not limited to DCI.

[0022] In the following description, a physical downlink shared channel (PDSCH) will be described as an example of a downlink shared channel, but the downlink shared channel may be any channel that is used at least for transmitting paging information, and its name is not limited to PDSCH.

[0023] (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.

[0024] FIG. 2 is a diagram for explaining DRX operation during paging. As shown in FIG. 2, a terminal 10 in an RRC idle (RRC_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 configuration, the base station 20 transmits a paging signal during the PO period and does not transmit a paging signal during other periods. When the terminal 10 receives a paging signal within the PO period, it establishes communication with the base station 20 and transitions to the RRC_CONNECTED state. One PO exists per DRX cycle. The maximum length of a DRX cycle is 2.56 seconds.

[0025] Fig. 3 is a diagram for explaining eDRX operation during paging. As shown in Fig. 3, a terminal 10 in an RRC idle state receives a paging signal by monitoring downlink control channel candidates in a PO period that exists within a period called a PTW (Paging Time Window). One PTW is set 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.

[0026] 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 RRC_CONNECTED state.

[0027] Here, PH is an H-SFN that satisfies the following formula 1. (Equation 1) H-SFN mod T eDRX,H = (UE_ID_H mod T eDRX,H ) TeDRX,H indicates the eDRX cycle and is set to a length that is an integral multiple of the hyperframe. 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).

[0028] The SFN, which is the start position (PTW_start) (start timing) of the PTW, is expressed by the following Equations 2 and 3. (Equation 2) SFN = 256 * i eDRX (Equation 3) i eDRX =floor(UE_ID_H / T eDRX,H ) mod 4

[0029] The SFN, which is the end position (PTW_end) (end timing) of the PTW, is expressed by the following Equation 4. (Equation 4) SFN = (PTW_start+L*100-1) mod 1024 L is the time length of the PTW (Paging Time Window length), and is set in the terminal 10 by a message from an upper layer (Radio Resource Control (RRC) or Non Access Stratum (NAS)).

[0030] (Challenges in implementing eDRX in NR) When applying eDRX to NR, the following issues are considered to arise. First, in eDRX in LTE, the possible values ​​for the start position of the PTW are limited to four. Specifically, according to the above equations 2 and 3, i eDRXSince the possible values ​​of SFN are 0, 1, 2, and 3, the start position of the PTW is limited to four values: SFN = 0, 256, 512, and 768. However, NR is designed to allow more flexible configuration of various settings required for wireless communication than LTE. Therefore, when implementing eDRX in NR, it is considered necessary to make the start position of the PTW more flexible than LTE (first issue).

[0031] Next, in NR, an area in which a terminal 10 monitors PDCCH candidates is called a search space. The search space is divided into a common search space (CSS) that is set in common to each terminal 10, and a UE specific search space (USS) that is set individually for each terminal 10.

[0032] In NR, it is possible to set a search space for each BWP, but the 3GPP specifications explicitly stipulate that in BWPs where a search space is not set, the terminal 10 does not monitor control channel candidates. However, since eDRX is not stipulated in NR, there is naturally no stipulation as to how the terminal 10 should operate in periods other than the PO period. In light of this situation, when eDRX is implemented in NR, it is considered necessary to specifically stipulate a mechanism by which the terminal 10 monitors radio signals in accordance with the DRX setting (second issue).

[0033] Next, NR defines a new RRC state called RRC inactive (RRC_INACTIVE). Like RRC idle, RRC inactive allows the terminal 10 to save power, but unlike RRC idle, the terminal 10, base station 20, and core network 30 maintain an RRC context and a NAS context. In addition, RAN notification areas (RNAs), which are areas obtained by subdividing a tracking area (TA), are defined, and the base station 20 manages the RAN notification areas in which the terminal 10 exists. In addition, a technology called "RAN paging" has been introduced, which performs paging processing in units of RAN notification areas and is used when calling a terminal 10 in the RRC inactive state.

[0034] In RAN paging, paging signals are simultaneously transmitted from multiple base stations 20 that constitute a RAN notification area in which the terminal 10 is located. Therefore, the base station 20 needs to share various pieces of information required for performing RAN paging with other base stations 20 that constitute the same RAN notification area.

[0035] In the case of a terminal 10 that is likely to move, such as a RedCap terminal 10 mounted on a vehicle, it is expected that the terminal 10 may transition to an RRC inactive state while operating in eDRX. Therefore, when realizing eDRX in NR, a mechanism is required that enables RAN paging processing to be performed taking eDRX into consideration, even when the terminal 10 that supports eDRX transitions to an RRC inactive state (third issue).

[0036] (Outline of this embodiment) In the wireless communication system according to this embodiment, to solve the first problem, the number of possible PTW start positions can be set to any number. Furthermore, to solve the second problem, a terminal 10 configured with eDRX monitors control channel candidates in a common search space for paging during the PTW, and operates so as not to monitor control channel candidates in the common search space during periods other than the PTW. Furthermore, to solve the third problem, when performing RAN paging, a base station 20 can notify other base stations 20 of eDRX-related configuration information using the Xn interface.

[0037] In this embodiment, setting information necessary to realize eDRX operation, such as the eDRX cycle (eDRX period) and the PTW time length (length of the reception period), is referred to as “setting information related to eDRX.” Furthermore, in the following description, unless otherwise specified, the term “setting information related to eDRX” may refer only to setting information related to eDRX, such as the eDRX cycle and the PTW time length, or may refer to setting information necessary to realize DRX operation, such as setting the DRX cycle and PO position, in addition to setting information related to eDRX.

[0038] <Hardware configuration> 4 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.

[0039] 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.

[0040] 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.).

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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. 4, or may include hardware not shown in Fig. 4. Furthermore, the hardware shown in Fig. 4 may be configured using one or more chips.

[0045] <Functional configuration> (Terminal) FIG. 5 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.

[0046] 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.

[0047] Furthermore, the receiving unit 101 receives from the base station 20 setting information related to eDRX and / or setting information related to the common search space.

[0048] The transmitter 102 transmits an uplink signal. The transmitter 102 may also transmit information and / or data 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.

[0049] The control unit 103 performs various processes related to eDRX based on the setting information related to eDRX received by the receiving unit 101. Furthermore, based on the setting information related to eDRX, the control unit 103 controls to monitor control channel candidates during a PTW (reception period) in a PH (predetermined H-SFN).

[0050] (base station) FIG. 6 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.

[0051] 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 setting information related to eDRX from the core network 30. The receiving unit 201 also receives various types of information from other base stations 20 using the Xn interface.

[0052] 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 various types of information to other base stations 20 using the Xn interface. The transmitter 202 also transmits configuration information related to eDRX and / or configuration information related to a common search space to the terminal 10.

[0053] Furthermore, the transmitter 202 transmits various types of information to other base stations 20. For example, when executing RAN paging processing for a terminal 10 in an RRC inactive state, the transmitter 202 transmits, to other base stations 20, a RAN paging information element including setting information related to eDRX.

[0054] The control unit 203 controls the RAN paging process for the terminal 10 in the RRC inactive state. Further, the control unit 203 controls to transmit downlink control information during the PTW (reception period) in the PH (predetermined H-SFN) indicated by the setting information regarding eDRX.

[0055] <Processing procedure when realizing eDRX in NR> (Sequence) FIG. 7 is a sequence diagram showing an example of a processing procedure regarding eDRX. In FIG. 7, it is assumed that the base stations 20-X and 20-Y constitute the same RAN notification area.

[0056]

[0057] In step S100, the terminal 10 transmits a registration request to the core network 30 via the base station 20. Here, it is assumed that the terminal 10 transmits the registration request via the base station 20-X.

[0058] Note that the setting information regarding eDRX is not limited to the processing procedures of steps S100 and S101, and may be set for the terminal 10 by any method. For example, instead of a NAS message, it may be set for the terminal 10 using an RRC message (e.g., (RRC Setup, RRC Reconfiguration, RRC Reestablishment, etc.).

[0059] ​In step S102, the base station 20-X receives an N2 message from the core network 30, the N2 message including configuration information related to eDRX configured in the terminal 10. The N2 message refers to a message used in the interface (N2 interface) between the base station 20 and the core network 30. The N2 message may be, for example, an Initial Context setup message, a UE context modification message, a Handover resource allocation message, or a Path switch request message. The configuration information related to eDRX may also be part of Core Network Assistance Information for RRC INACTIVE.

[0060] In step S103, the terminal 10 transitions to an RRC inactive state. In the RRC inactive state, the RRC context (AS context) related to the terminal 10 is held in the terminal 10 and the base station 20-X.

[0061] In step S104, the core network 30 (for example, the UPF) transmits downlink data (user plane data or downlink signaling) to be transmitted to the terminal 10 to the base station 20-X.

[0062] In step S105, the base station 20-X receives downlink data to be transmitted to the terminal 10, but detects that an event that should trigger RAN paging has occurred because the terminal 10 is in the RRC inactive state.

[0063] In step S106, the base station 20-X transmits RAN paging information to another base station 20 (here, base station 20-Y) associated with the same RAN notification area as the base station 20-X. The other base station 20 may be referred to as the base station 20 corresponding to the RAN notification area in which the terminal 10 is located. In addition, the base station 20-X transmits the setting information related to eDRX received in the processing procedure of step S102, by including it in the RAN paging information.

[0064] In step S107, the base station 20-X and the base station 20-Y transmit paging information to the terminal 10. Here, the base station 20-X and the base station 20-Y transmit the paging information in the PTW period (more specifically, in the PO period that exists in the PTW period) in accordance with the setting information related to eDRX. Furthermore, the base station 20 does not transmit the paging information in periods other than the PTW period. Note that, more specifically, when the base station 20 transmits paging information in the PTW period, it means transmitting downlink control information that indicates, for example, the resource position of the physical downlink shared channel in which the paging information is transmitted, within the common search space in the PTW period.

[0065] In step S108, the terminal 10 monitors control channel candidates in the search space during the PTW period in the PH (more specifically, during the PO period that exists in the PTW period) in accordance with the configured setting information related to eDRX. When downlink control information corresponding to paging information is detected by monitoring the control channel candidates in the search space, the terminal 10 receives the paging information by demodulating and decoding the physical downlink shared channel in accordance with the downlink control information.

[0066] Here, in NR, multiple common search spaces as shown below are defined, and configuration information regarding these multiple common search spaces is transmitted (configured) from the base station 20 to the terminal 10 using system information or individual RRC messages (RRC Setup, RRC Reconfiguration, RRC Reestablishment, etc.).

[0067] Common search space (Type0-PDCCH CSS set) in which downlink control information indicating the radio resource in which SIB1 (System Information Block 1) is placed is transmitted Common search space (Type0A-PDCCH CSS set) in which downlink control information indicating the radio resources in which system information other than SIB1 (SIB2, SIB3, etc.) is allocated is transmitted Common search space (Type1-PDCCH CSS set) in which downlink control information used to receive message 1 in the random access procedure is transmitted Common search space (Type2-PDCCH CSS set) in which downlink control information indicating the radio resources where paging information is placed is transmitted Common search space (Type3-PDCCH CSS set) in which downlink control information indicating the radio resources where normal data such as user data is placed is transmitted That is, the base station 20 transmits a downlink control signal in a search space for paging (Type2-PDCCH CSS set) among multiple common search spaces indicated in the setting information regarding the common search space during the PTW period in the PH indicated in the setting information regarding eDRX. Also, the terminal 10 monitors control channel candidates in the search space for paging (Type2-PDCCH CSS set) among multiple common search spaces indicated in the setting information regarding the common search space during the PTW period in the PH indicated in the setting information regarding eDRX.

[0068] Furthermore, base station 20 may not transmit downlink control information within the paging search space during periods other than the PTW in the PH. Furthermore, terminal 10 may not monitor control channel candidates within the paging search space during periods other than the PTW in the PH. By not monitoring control channel candidates within the paging search space during periods other than the PTW in the PH, it is possible to reduce battery consumption in terminal 10.

[0069] In this embodiment, a new common search space for paging may be defined, in which the search space duration is changed to be the same as the eDRX configuration. Specifically, a new common search space for paging may be defined, in which a PO period existing in a PTW period is used as the search space, and the terminal 10 may monitor control channel candidates according to the configuration of the new common search space. The configuration of the new common search space may be notified to the terminal 10 using an RRC message or an NAS message.

[0070] (eDRX settings) The setting information related to eDRX in the processing procedures of steps S101, S102, S106, S107, and S108 in FIG. 7 will be described using several specific examples.

[0071] [Example of setting information 1] The wireless communication system according to this embodiment may perform eDRX operations similar to those of 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 setting information related to eDRX may include the eDRX cycle (T in Equations 1 and 3). eDRX,H ) and the time length of the PTW (L in Equation 4). For example, in the processing procedure of step S106, the base station 20-X transmits eDRX-related setting information, including information indicating the eDRX cycle and the time length of the PTW, in the RAN paging information.

[0072] [Example of setting information 2] The wireless communication system according to this embodiment may include predetermined information related to setting the start position of a PTW in the setting information related to eDRX, thereby making it possible to set the start position of a PTW more flexibly than in LTE.

[0073] For example, the predetermined information regarding the setting of the start position of a PTW may include information indicating the number of start positions of a PTW in a PH (the number of SFNs that can be set as the start SFN of a PTW), and the start position of a PTW may be determined by inputting the information indicating the number of start positions of a PTW in a PH into a predetermined calculation formula. The predetermined calculation formula may be Equation 5 and Equation 6 shown below. The end position of a PTW may also be determined according to Equation 4, as in LTE.

[0074] (Equation 5) SFN = (1024 div N PTW )*i eDRX (Equation 6) i eDRX =floor(UE_ID_H / T eDRX,H ) mod N PTW In Equations 5 and 6, N PTW is information indicating the number of start positions of PTW in PH. For example, N PTW If =8, i eDRX The possible values ​​of 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 = 4, Equations 5 and 6 are the same as Equations 2 and 3, respectively. That is, by using Equations 5 and 6, it is possible to set the start position of the PTW more flexibly than in LTE.

[0075] 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 setting information regarding eDRX includes the eDRX cycle (T in Equation 6). eDRX,H ), the time length of the PTW (L in Equation 4), and the number of start positions of the PTW in the PH (N in Equation 5). PTW) are included. For example, in the processing procedure of step S101, the terminal 10 receives a NAS message or an RRC message having configuration information related to eDRX, which includes information indicating the eDRX cycle, the time length of the PTW, and the number of start positions of the PTW in the PH (predetermined information related to setting the start positions of the PTW). Furthermore, in the processing procedure of step S106, the base station 20-X transmits the configuration information related to eDRX, which includes information indicating the eDRX cycle, the time length of the PTW, and the number of start positions of the PTW in the PH (predetermined information related to setting the start positions of the PTW), in RAN paging information.

[0076] [Example of setting information 3] In the wireless communication system 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 allows the end position of the PTW to be set flexibly.

[0077] In this case, the setting information related to eDRX includes 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. For example, in the processing procedure of step S101, the terminal 10 receives an NAS message or an RRC message having setting information related to eDRX, including 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. Furthermore, in the processing procedure of step S106, the base station 20-X transmits, in RAN paging information, the setting information related to eDRX, including the eDRX cycle, information specifying a radio frame indicating the start position of the PTW, and information specifying a radio frame indicating the end position of the PTW.

[0078] <Example of specification change> 8 to 14 are diagrams showing examples of specification changes in the 3GPP specifications. The underlined parts in Fig. 8 and Fig. 9 show examples of specification changes related to the operation of the terminal 10 described in the processing procedure of step S108 in Fig. 7.

[0079] Fig. 10 shows an example of specification changes when Paging eDRX information, which is setting information related to eDRX, is added to the RAN paging information, as described in the processing procedure of step S106 in Fig. 7. Fig. 11 and Fig. 12 show specific examples of eDRX parameters included in the Paging eDRX information. Fig. 11 corresponds to specific example 1 of setting information, and Fig. 12 corresponds to specific example 2 of setting information.

[0080] 11 and 12, "Paging eDRX Cycle" corresponds to the eDRX cycle, "Paging Time Window" corresponds to the time length of the PTW, and "Number of PTWs" in Fig. 12 corresponds to the number of PTW start positions in the PH.

[0081] Fig. 13 shows an example format of paging eDRX information. The format shown in Fig. 13 includes the eDRX parameters shown in Fig. 11. Fig. 13 and Fig. 14 show example specification changes when defining the protocol ID of paging eDRX information.

[0082] <Summary> According to the embodiment described above, in response to the first problem, the number of possible PTW start positions can be set to any number. This allows for more flexible operation configuration related to eDRX. In response to the second problem, a terminal 10 configured with eDRX monitors a common search space for paging during a PTW and does not monitor the common search space during periods other than the PTW. This enables the user terminal to perform appropriate monitoring operations when eDRX is introduced into NR. It also reduces the power consumption of the terminal 10. In response to the third problem, when RAN paging is performed, a base station 20 can notify other base stations 20 of eDRX configuration information. This allows RAN paging to be performed even when a terminal supporting eDRX has transitioned to RRC inactive.

[0083] <Other embodiments> In the above embodiment, "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)."

[0084] 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.

[0085] 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).

[0086] 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.

[0087] 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.).

[0088] 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.

[0089] The above-described embodiments are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. The flowcharts, sequences, elements included in the embodiments, and their arrangements, indexes, conditions, etc. described in the embodiments are not limited to those exemplified and can be modified as appropriate. Furthermore, at least some of the configurations described in the above embodiments can be partially replaced or combined. [Explanation of symbols]

[0090] 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 information indicating an eDRX cycle and information indicating a time length of a paging time window (PTW); a control unit that controls monitoring of physical downlink control channel candidates (PDCCH candidates) within a paging search space in a PTW in a predetermined H-SFN indicated by the eDRX cycle; and The start position of the PTW is determined by inputting a UE_ID_H given by a hash ID of a TMSI, the eDRX cycle, and the number (N) of possible start positions of the PTW into a first calculation formula; N is 8, The end position of the PTW is determined by inputting the determined start position of the PTW and the time length of the PTW into a second calculation formula. Terminal.

2. The information indicating the eDRX cycle is included in a NAS message. The terminal according to claim 1 .

3. Information indicating the time length of the PTW is included in an RRC message.

3. The terminal according to claim 1 or 2.

4. The start position and end position of the PTW are represented by a System Frame Number. A terminal according to any one of claims 1 to 3.

5. The start position of the PTW is determined by dividing UE_ID_H, which is given by the hash ID of the TMSI, by the eDRX cycle, and inputting the remainder obtained by dividing the result, truncated to any whole number, by N=8 into a predetermined calculation formula. A terminal according to any one of claims 1 to 4.

6. The TMSI is a 5G-S-TMSI. A terminal according to any one of claims 1 to 5.

7. a transmitter that transmits information indicating an eDRX cycle and information indicating a time length of a paging time window (PTW); a control unit that controls transmission of physical downlink control information (PDCCH candidates) within a paging search space in a PTW in a predetermined H-SFN indicated by the eDRX cycle; and The start position of the PTW is determined by inputting a UE_ID_H given by a hash ID of a TMSI, the eDRX cycle, and the number (N) of possible start positions of the PTW into a first calculation formula; N is 8, The end position of the PTW is determined by inputting the determined start position of the PTW and the time length of the PTW into a second calculation formula. Base station.

8. receiving information indicating an eDRX cycle and information indicating a time length of a paging time window (PTW); controlling a PTW in a predetermined H-SFN indicated by the eDRX cycle to monitor physical downlink control channel candidates (PDCCH candidates) within a paging search space; Including, The start position of the PTW is determined by inputting a UE_ID_H given by a hash ID of a TMSI, the eDRX cycle, and the number (N) of possible start positions of the PTW into a first calculation formula; N is 8, The end position of the PTW is determined by inputting the determined start position of the PTW and the time length of the PTW into a second calculation formula. A wireless communication method used by a terminal.

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