Title: terminal and communication method

Abstract

To avoid a mismatch in recognition between a terminal and a base station when the terminal falls back from a state of monitoring an LP-WUS to a state of monitoring a PDCCH.SOLUTION: A terminal comprises: a control unit configured to determine whether to perform fallback from a state of monitoring a low-power signal to a state of monitoring a control channel; and a transmission unit configured to transmit a fallback notification to a base station.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a terminal and a communication method in a wireless communication system. [Background technology]

[0002] 3GPP (registered trademark) (3rd Generation Partnership Project) Release 18 (Rel-18) introduced the Low-Power Wake-Up Signal (LP-WUS). LP-WUS is a mechanism that uses a low-power, always-operable wake-up receiver (WUR) to determine the presence or absence of paging with minimal reception capabilities.

[0003] In 3GPP Rel-19, terminal operation when the terminal (UE) falls back from a state in which it monitors the LP-WUS to a state in which it monitors the PDCCH is under consideration. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V18.5.0(2025-03) Summary of the Invention [Problem to be solved by the invention]

[0005] If the base station continues to transmit the LP-WUS even after the terminal autonomously performs fallback and stops monitoring the LP-WUS, radio resources will be wasted. However, in conventional technologies, when the terminal autonomously performs fallback, it is not possible to avoid mismatch in perception between the terminal and the base station, which can result in the above-mentioned waste of radio resources.

[0006] The present invention has been made in consideration of the above points, and aims to provide a technique for avoiding mismatch in perception between a terminal and a base station when the terminal falls back from a state of monitoring LP-WUS to a state of monitoring PDCCH. [Means for solving the problem]

[0007] According to this embodiment, the terminal includes a control unit that determines to perform a fallback from a state of monitoring a low power signal to a state of monitoring a control channel, and a transmission unit that transmits a fallback notification to the base station. [Effects of the Invention]

[0008] According to this embodiment, a technique is provided for avoiding mismatch in perception between a terminal and a base station when the terminal falls back from a state of monitoring LP-WUS to a state of monitoring PDCCH. [Brief explanation of the drawings]

[0009] [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. 3 is a diagram for explaining an example of operation in the first embodiment. [Figure 3] FIG. 10 is a diagram for explaining an example of the operation of Alt. 2 in the first embodiment. [Figure 4] FIG. 10 is a diagram for explaining an example of operation of option 2 in the third embodiment. [Figure 5] FIG. 2 is a diagram illustrating an example of a functional configuration of a base station according to the present embodiment. [Figure 6] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal according to the present embodiment. [Figure 7] FIG. 2 is a diagram illustrating an example of a hardware configuration of a base station or a terminal according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the present embodiment (including the first, second, and third embodiments described later) will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiments to which the present invention is applied are not limited to the following embodiments.

[0011] In operation of the wireless communication system of the present embodiment, an existing technology may be used as appropriate. The existing technology is, for example, the existing LTE or the existing NR, but is not limited to the existing LTE or NR.

[0012] Furthermore, in the present embodiment described below, terms used in existing technologies, such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel), are used. This is for convenience of description, and similar signals, functions, etc. may be referred to by other names. Furthermore, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even signals used in NR are not necessarily designated as "NR-".

[0013] Furthermore, in this embodiment, the duplex method may be a time division duplex (TDD) method, a frequency division duplex (FDD) method, or other methods (for example, flexible duplex, etc.).

[0014] Furthermore, in this embodiment, "configuring" radio parameters etc. may mean that predetermined values ​​are pre-configured, or that radio parameters notified from a base station or a terminal are set.

[0015] (System Configuration) Fig. 1 is a diagram for explaining a wireless communication system in this embodiment. As shown in Fig. 1, the wireless communication system in this embodiment includes a base station 10 and a terminal 20. Although Fig. 1 shows one base station 10 and one terminal 20, this is an example, and there may be a plurality of each.

[0016] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain, and the time domain may be defined by the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. Furthermore, a TTI (Transmission Time Interval) in the time domain may be a slot, or a TTI may be a subframe.

[0017] The base station 10 transmits a synchronization signal and system information to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is transmitted, for example, via the NR-PBCH and is also referred to as notification information or broadcast information. The synchronization signal and system information may be referred to as an SSB (SS / PBCH block). As shown in FIG. 1 , the base station 10 transmits control signals or data to the terminal 20 via DL (Downlink) and receives control signals or data from the terminal 20 via UL (Uplink). Both the base station 10 and the terminal 20 are capable of transmitting and receiving signals by performing beamforming. Furthermore, both the base station 10 and the terminal 20 are capable of applying MIMO (Multiple Input Multiple Output) communication to DL or UL. Furthermore, both the base station 10 and the terminal 20 may communicate via a secondary cell (SCell) and a primary cell (PCell) using CA (Carrier Aggregation). Furthermore, the terminal 20 may perform communication via a primary cell of the base station 10 and a primary secondary cell group cell (PSCell: Primary SCG Cell) of another base station 10 using DC (Dual Connectivity).

[0018] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, or an M2M (Machine-to-Machine) communication module. As shown in FIG. 1, the terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. The terminal 20 also receives various reference signals transmitted from the base station 10 and measures the propagation path quality based on the reception results of the reference signals. The terminal 20 may be referred to as a UE 20, and the base station 10 may be referred to as a gNB 10.

[0019] (About LP-WUS) The Low-Power Wake Up Signal is called LP-WUS or simply WUS, and the Low-Power Wake Up Receiver is called LP-WUR, WUR, or LR. The LR, a simple circuit that operates with lower power consumption than the Main Radio (MR) used in normal data communications, operates as a replacement for the MR, introducing a state called Ultra-Deep Sleep. The LR may have a function that triggers the power OFF of the MR or the power ON of the MR when the LR receives the LP-WUS signal. The terminal 20 (specifically, for example, the receiving unit 220) in this embodiment has an MR and an LR.

[0020] The agreement on the scope of application of LP-WUS / WUR in 3GPP Rel-19 is shown below.

[0021] To specify a LP-WUS design that is commonly applicable to both RRC IDLE / INACTIVE and RRC CONNECTED modes, an LP-WUS is specified that is based on an OOK (OOK-1 and / or OOK-4) waveform, with an OFDM sequence overlaid on the OOK symbols as needed. At a minimum, duty cycle monitoring of the LP-WUS must be supported. In IDLE / INACTIVE operation, the same information must be delivered regardless of the type of LP-WUS, and the OFDM sequence may carry the information.

[0022] In RRC IDLE / INACTIVE mode, - Specifying the procedures and configurations for LP-WUS to indicate paging monitoring triggered by LP-WUS, including at least the configuration, subgrouping and entry / exit conditions for LP-WUS monitoring.

[0023] - For synchronization and / or serving cell RRM, the LP-WUR is assigned an LP-SS with a periodicity of Y [ms]. The LP-SS is based on OOK-1 and / or OOK-4 waveforms, with or without an OFDM sequence overlay. For LP-WURs that can receive existing PSS / SSS, the existing PSS / SSS can be used instead of the LP-SS for synchronization and RRM.

[0024] - Specify further relaxation of UE MR RRM for both serving and neighbor cell measurements and offloading of UE serving cell RRM measurements from MR to LP-WUR, including the necessary conditions.

[0025] In RRC CONNECTED mode, it specifies the procedure to enable UE MR PDCCH monitoring triggered by LP-WUS, including the procedure to enable and disable LP-WUS monitoring. In CONNECTED mode, UE MR ultra-deep sleep is not considered, and UE RRM / RLM / BFD / CSI measurements are performed by MR.

[0026] The target coverage of LP-WUS and LP-SS is the PUSCH coverage of message 3. Optimization of LP-WUS signal design for idle / inactive mode takes priority over optimization for connected mode.

[0027] Below we will explain LP-WUS for connected mode Option 1-1 / 1-2 and the recent agreements regarding LP-WUS for connected mode.

[0028] (LP-WUS for connected mode Option 1-1 / 1-2) <Option 1-1> In LP-WUS CONNECTED mode operation option 1-1, the following behavior is assumed:

[0029] The terminal 20 performs LP-WUS monitoring according to the LP-WUS monitoring setting before the drx-onDurationTimer to trigger the start of the drx-onDurationTimer.

[0030] In the terminal 20, a legacy C-DRX similar to that in Rel-18 is set.

[0031] The terminal behavior related to the CDRX active time triggered by the legacy DRX timer is not affected unless included in this proposal.

[0032] No impact on RRM / RLM / BFD measurement requirements is expected.

[0033] For periodic CSI / L1-RSRP reporting, terminal 20 may be configured with one of the following (same as Rel-16 DCP): Periodic CSI / L1-RSRP is not reported during the time given by the configured drx-onDurationTimer if the terminal 20 has not been instructed to wake up.

[0034] Periodic CSI / L1-RSRP is reported periodically during the time given by the configured drx-onDurationTimer, regardless of whether the terminal 20 is instructed to wake up. Note that periodic CSI / L1-RSRP is reported during the CDRX active time, as in the legacy specification. <Option 1-2> For LP-WUS CONNECTED mode operation options 1-2, the following behavior is expected:

[0035] The terminal 20 performs LP-WUS monitoring at least outside the legacy C-DRX active time in accordance with the LP-WUS monitoring configuration to trigger PDCCH monitoring.

[0036] In the terminal 20, legacy C-DRX is set up in the same way as in Rel-18.

[0037] It is assumed that the terminal 20 is configured with LP-WUS monitoring (the period and offset may be different from those of C-DRX).

[0038] The LP-WUS triggers the start of a timer for the terminal 20 to monitor the PDCCH.

[0039] The UE PDCCH monitoring behavior related to other legacy DRX timers is not affected, such as drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerUL.

[0040] No impact on RRM / RLM / BFD measurement requirements is expected. For periodic CSI / L1-RSRP reporting, the terminal 20 may be configured with one of the following (same as Rel-16 DCP and Option 1-1):

[0041] Periodic CSI / L1-RSRP is not reported if the terminal 20 is not instructed to wake up.

[0042] Periodic CSI / L1-RSRP is reported periodically regardless of whether the terminal 20 is instructed to wake up or not.

[0043] The PDCCH monitoring of the terminal 20 is not triggered by the legacy C-DRX cycle and drx-onDurationTimer when monitoring the LP-WUS.

[0044] Option 1-2 also introduces a new timer that is triggered by the LP-WUS. When this new timer is running, the terminal 20 is in the C-DRX active time. When the terminal 20 is not in the C-DRX active time, the terminal 20 returns to LP-WUS monitoring.

[0045] When the terminal 20 is in the C-DRX active time, the UE PDCCH monitoring behavior related to other legacy DRX timers (except drx-onDurationTimer) is not affected.

[0046] (Regarding recent agreements and proposals) <Agreements in RAN1#116> In the case of RRC CONNECTED mode, the following operations are assumed to be performed.

[0047] · PDCCH monitoring triggered by LP-WUS is enabled / disabled by gNB RRC signaling.

[0048] · The fact that the terminal 20 monitors LP-WUS is notified to the base station 10.

[0049] · When LP-WUS monitoring is enabled, the following options are further considered.

[0050] Option 1: No additional instructions / conditions are introduced for activating / deactivating LP-WUS monitoring.

[0051] Option 2: Activation / deactivation of LP-WUS monitoring by gNB L1 / L2 signaling with or without UE assistance is introduced.

[0052] Option 3: Activation / deactivation of LP-WUS monitoring based on conditions such as a timer is introduced.

[0053] Option 4: Implicit instructions / conditions, for example, activation / deactivation of LP-WUS monitoring based on UL transmission, are introduced.

[0054] <Conclusion in RAN1#120> When LP-WUS monitoring is enabled in RRC CONNECTED mode, SR, PRACH, and CG-PUSCH are supported to trigger MR PDCCH monitoring according to legacy UE behavior. This applies at least to Option 1-1 described above.

[0055] <Conclusion at RAN1#120b> When LP-WUS monitoring Option 1-2 is enabled for RRC CONNECTED mode, SR, PRACH, and CG-PUSCH are supported to trigger PDCCH monitoring according to legacy UE behavior.

[0056] <Proposal 4-1b in RAN1#120bis> When LP-WUS monitoring Option 1-1 is enabled for RRC CONNECTED mode, UE 20 can fallback to PDCCH monitoring when UE 20 monitors LP-WUS. However, whether / how conditions are considered for fallback is under consideration. For Option 1-1 of LP-WUS operation, UE 20 falls back to legacy C-DRX behavior.

[0057] (Regarding the issue) UE 20 autonomously falling back from the LP-WUS monitoring state to the PDCCH monitoring state can be beneficial when the semi-static activation / deactivation cannot track the latest channel quality.

[0058] When UE 20 performs autonomous fallback (i.e., when UE 20 stops monitoring LP-WUS), it is necessary for the base station 10 to know this. This is because the base station 10 transmitting LP-WUS not monitored by UE 20 would be a waste of radio resources.

[0059] In view of the above, in this embodiment, the terminal 20 notifies the base station 10 whether or not to execute autonomous fallback. The technology according to this embodiment will be described below. In this embodiment, the LP-WUS is an example of a low-power signal. The PDCCH is an example of a control channel.

[0060] (Outline of the embodiment) In this embodiment, the terminal 20 notifies the base station 10 of an indication that fallback to PDCCH monitoring will be performed during LP-WUS monitoring. More specific operation examples include the following first, second, and third embodiments. Note that in each embodiment, "notification" may be replaced with "instruction," "display," etc.

[0061] First embodiment: Various approaches to fallback notification, including Alt. 1 to 4 below.

[0062] Alt. 1: The terminal 20 sends a scheduling request (SR) as a fallback notification.

[0063] Alt. 2: The terminal 20 sends a MAC CE message as a fallback notification.

[0064] Alt. 3: The terminal 20 sends an RRC message as a fallback notification.

[0065] Alt. 4: The terminal 20 transmits a PRACH as a fallback notification.

[0066] Second embodiment: An embodiment regarding the operation of the terminal 20 when the base station 10 does not receive a fallback notification transmitted from the terminal 20.

[0067] Third embodiment: An embodiment regarding a time point at which the terminal 20 no longer needs to monitor the LP-WUS after sending a fallback notification.

[0068] Each embodiment will be described in detail below. In the following description, " / " represents "or." For example, "A / B" means "A or B."

[0069] (First embodiment) In the first embodiment, when the terminal 20 is configured for LP-WUS monitoring and the terminal 20 [wants to fall back / has already fallen back] to PDCCH monitoring (i.e., does not monitor LP-WUS), the terminal 20 transmits a fallback notification to the base station 10. Note that "the terminal 20 [wants to fall back / has already fallen back] to PDCCH monitoring" includes "the terminal 20 decides to fall back from a state of monitoring LP-WUS to a state of monitoring PDCCH."

[0070] Furthermore, for a terminal 20 configured for LP-WUS monitoring, after the terminal 20 sends a fallback notification to the base station 10, or after the terminal 20 sends a fallback notification and receives a response to the fallback notification from the base station 10, the terminal 20 is [not required / expected / not expected] to monitor the LP-WUS.

[0071] An example of operation in the first embodiment will be described with reference to FIG.

[0072] In S101 (step 101), the terminal 20 monitors the LP-WUS transmitted from the base station 10.

[0073] In S102, the terminal 20 decides to perform fallback to PDCCH monitoring. In S103, the terminal 20 transmits a fallback notification to the base station 10. In S104, the terminal 20 determines not to monitor the LP-WUS. Furthermore, the base station 10, which has received the fallback notification, also determines that the terminal 20 does not monitor the LP-WUS.

[0074] Below, Alt. 1 to 4 will be explained as a more specific example of operation.

[0075] <Alt.1> The terminal 20 transmits a scheduling request (SR) as a fallback notification to the base station 10. Alt.1 includes the following Alt.1a to 1c.

[0076] Alt.1a: The existing SR message is used as a fallback notification, in which case any SR is considered a fallback notification by the base station 10, even if it is a normal SR requesting an UL grant.

[0077] Alt.1b: An extended SR message is used as the fallback notification. For example, the SR message includes two bits, and the terminal 20 can use these two bits to indicate whether or not to fall back. Specific examples of the values ​​of the two bits are as follows:

[0078] "00": No UL grant requested, no fallback "01": Request UL grant '10': Request fallback to PDCCH monitoring, no UL grant requested '11': Request UL grant and fallback to PDCCH monitoring Alt.1c: Use a dedicated SR configuration (e.g., PUCCH resources) for fallback notification that is different from the legacy SR configuration.

[0079] This concludes the explanation of Alt.1a to 1c.

[0080] In Alt. 1, the terminal 20 may or may not expect to receive a PDCCH with an UL grant triggered by an SR in response to the fallback notification.

[0081] If the terminal 20 receives a PDCCH with an UL grant triggered by an SR or a PDCCH with an UL grant after an SR transmission, the terminal 20 determines that the base station 10 has received a fallback notification.

[0082] If the terminal 20 does not receive a PDCCH with an UL grant triggered by an SR or a PDCCH with an UL grant after an SR transmission within a time window, the terminal 20 determines that the base station 10 has not received a fallback notification. The time window may be a legacy monitoring window after an SR transmission or a newly defined window for fallback notification.

[0083] <Alt.2> In Alt.2, the terminal 20 transmits a MAC CE message as a fallback notification to the base station 10. Specifically, the process is as follows.

[0084] A new MAC CE may be defined to include the fallback information, or an existing MAC CE may be extended to include the fallback information.

[0085] For example, the MAC CE of BSR (Buffer Status Report) can be extended to include the fallback notification, and for example, a 1-bit fallback notification may be included in the existing / new MAC CE.

[0086] For a terminal 20 configured for LP-WUS monitoring, if the terminal 20 sends a fallback notification MAC CE and [receives a response to the MAC CE fallback notification from the base station 10 (i.e., if the HPN NDI for the MAC CE is reset), or if the fallback notification bit exists, or if the fallback notification bit is set to true or false], the terminal 20 is [not required / expected / not expected] to monitor the LP-WUS.

[0087] After sending the fallback notification by the MAC CE in the PUSCH with the HARQ ID, the terminal 20 determines that the base station 10 has successfully received the fallback notification if:

[0088] Case 1-1: When the terminal 20 monitors (or receives) a PDCCH that schedules a new PUSCH transmission with the same HARQ ID.

[0089] Case 1-2: If the terminal 20 does not monitor / detect / receive a PDCCH scheduling a PUSCH retransmission with the same HARQ ID before the end of the drx-RetransmissionTimerUL timer. When the terminal 20 transmits a PUSCH, it starts the timer drx-RetransmissionTimerUL to monitor its retransmission. If the timer expires and no retransmission scheduling has been received, it means that the base station 10 has successfully received the PUSCH.

[0090] An example of operation in Alt.2 will be described with reference to FIG.

[0091] In S201, the terminal 20 transmits an SR to the base station 10 on a PUCCH. In S202, the terminal 20 receives a PDCCH with an UL grant from the base station 10. In S203, the terminal 20 transmits a PUSCH with a fallback notification by MAC CE to inform the base station 10 that it will not monitor LP-WUS. In S204, the terminal 20 determines whether the base station 10 has received the notification, for example, based on whether there is a response from the base station 10.

[0092] When the PUSCH is used for the fallback notification, information indicating that the fallback notification is being used (for example, a specific bit value) may be included in data other than the MAC CE. In other words, when transmitting data on the PUSCH, the terminal 20 may transmit the data by including the fallback notification in the data.

[0093] <Alt.3> Next, Alt. 3 will be described. In Alt. 3, the terminal 20 transmits an RRC message as a fallback notification to the base station 10. Specifically, this is as follows.

[0094] The fallback information is included in a new IE or an extended existing IE, for example, a 1-bit fallback indication can be included in the RRC IE.

[0095] For a terminal 20 configured for LP-WUS monitoring, if the terminal 20 sends a fallback notification RRC message and [if a response to the RRC fallback notification is received from the base station 10 (i.e., if the HPN NDI for the RRC message is reset), or if the fallback notification bit is present, or if the fallback notification bit is set to true or false], the terminal 20 is [not required / expected / not expected] to monitor the LP-WUS.

[0096] After sending the fallback notification on the PUSCH with the HARQ ID by RRC, the terminal 20 determines that the base station 10 has successfully received the fallback notification if:

[0097] Case 2-1: Same as Case 1-1 of Alt.2 above.

[0098] Case 2-2: Same as Case 1-2 of Alt.2 above.

[0099] Case 2-3: When the terminal 20 receives an RRC message from the base station 10 indicating that the base station 10 has correctly received the fallback notification.

[0100] <Alt.4> Next, Alt.4 will be described. In Alt.4, the terminal 20 transmits [Msg1 for PRACH / random access] as a fallback notification. This transmission is the same as Msg1 based on on-demand OSI. Specifically, it is as follows.

[0101] A [PRACH preamble / PRACH opportunity] or a set of [PRACH preamble / PRACH opportunity] may be reserved for fallback notification.

[0102] In the case of a terminal 20 configured for LP-WUS monitoring, after the terminal 20 transmits a fallback notification PRACH to the base station 10, or after the terminal 20 transmits a PRACH and receives a response to the PRACH from the base station 10, the terminal 20 is [not required / expected / not expected] to monitor the LP-WUS.

[0103] The terminal 20 may or may not expect to receive a RAR (Random Access Response) in response to the fallback notification.

[0104] If the terminal 20 receives an RAR in response to the fallback notification within the RAR window, the terminal 20 considers that the base station 10 has received the fallback notification.

[0105] If the terminal 20 does not receive an RAR in response to the fallback notification within the RAR window, the terminal 20 determines that the base station 10 did not receive the fallback notification. The RAR window length may reuse a legacy parameter (reuse the RAR window length of Msg1 based on on-demand OSI) or may be newly defined.

[0106] <Common matters for Alt. 1 to 4> The terminal 20 may be able to send a fallback notification in any of the following cells / BWPs.

[0107] · Only the Pcell or only the PSCell for each cell group.

[0108] · Any serving cell.

[0109] · Only the initial / default BWP.

[0110] · Any active BWP.

[0111] <Effect of the first embodiment> According to the first embodiment, since the terminal 20 sends a fallback notification to the base station 10, the base station 10 can grasp that the terminal 20 performs a fallback.

[0112] (Second embodiment) Next, the second embodiment will be described. In the second embodiment, the operation of the terminal 20 when the base station 10 does not receive a fallback notification will be described.

[0113] When the terminal 20 does not receive a PDCCH with a UL grant (for example, when the base station 10 does not receive an SR), the terminal 20 executes any one of the following operations 1 to 4. That is, when the terminal 20 determines that the base station 10 does not receive a fallback notification, the terminal 20 executes any one of the following operations 1 to 4.

[0114] Option 1: The terminal 20 re-sends the fallback notification. The total number of fallback notification transmissions and re-transmissions is not greater than a pre-defined / set number. If the total number exceeds the pre-defined / set number, the terminal 20 may perform operations of other options.

[0115] Option 2: The terminal 20 remains in the LP-WUS monitoring state, i.e., the terminal 20 does not perform fallback to PDCCH monitoring.

[0116] Option 3: Terminal 20 performs fallback to PDCCH monitoring. That is, terminal 20 does not perform LP-WUS monitoring but falls back to PDCCH monitoring. Specifically, terminal 20 performs PDCCH monitoring by one of the following three methods.

[0117] PDCCH monitoring is performed without a C-DRX timer, i.e., PDCCH monitoring is always performed.

[0118] ·Perform PDCCH monitoring based on the C-DRX timer.

[0119] · PDCCH monitoring is performed based on a new timer (e.g., the new timer for Option 1-2 in the above-mentioned agreement description).

[0120] Option 4: The terminal 20 executes random access. For example, in the cases of Alt1 to Alt3 of the first embodiment, if the base station 10 does not receive a fallback notification, the terminal 20 attempts to execute random access for RRC reconfiguration to notify the base station 10 of the fallback. In executing random access, the terminal 20 transmits a random access preamble to the base station 10.

[0121] <Effects of the second embodiment> According to the second embodiment, when it is determined that the base station 10 has not received a fallback notification from the terminal 20, the terminal 20 can continue to operate appropriately.

[0122] (Third embodiment) Next, a third embodiment will be described. In the third embodiment, a time point at which the terminal 20 no longer needs to monitor the LP-WUS after the terminal 20 transmits a fallback notification will be described.

[0123] After a certain point after sending the fallback notification, the terminal 20 does not need to monitor the LP-WUS, or the terminal 20 assumes that the base station 10 will not send the LP-WUS to the terminal 20, or the terminal 20 starts monitoring the PDCCH.

[0124] The above "point in time" can be determined (determined) using the following options 1 and 2. Here, this "point in time" will be called the point in time when LP-WUS monitoring is no longer necessary.

[0125] <Option 1> In option 1, a response from the base station 10 to the fallback notification is not required for the terminal 20 and the base station 10 to determine the time position at which LP-WUS monitoring is no longer required. More specifically, option 1 includes the following options.

[0126] Option 1-1: The terminal 20 and the base station 10 determine the point in time at which LP-WUS monitoring is no longer necessary as the time position at the end of the last symbol including the SR. Option 1-1 is suitable for Alt. 1 of the first embodiment.

[0127] Option 1-1a: The terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time position at the end of n1 symbols after the last symbol containing the SR.

[0128] Option 1-1b: When the SR or the last symbol of the SR is transmitted in slot m, the terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time point at the end of slot m+s1.

[0129] Option 1-2: The terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is no longer required is the time point at the end of the last symbol of the PUSCH having the MAC CE / RRC fallback notification. Option 1-2 is suitable for Alt. 2 / 3 of the first embodiment.

[0130] Option 1-2a: The terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time point at the end of n2 symbols after the last symbol of the PUSCH.

[0131] Option 1-2b: When the PUSCH or the last symbol of the PUSCH is transmitted in slot m, the terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time point at the end of slot m+s2.

[0132] Option 1-3: The terminal 20 and the base station 10 determine the point in time when LP-WUS monitoring is no longer necessary as the time position of the end of the last symbol of the PRACH for fallback notification. Options 1-3 are suitable for Alt.4 of the first embodiment.

[0133] Option 1-3a: The terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time point at the end of n3 symbols after the last symbol of the PRACH.

[0134] Option 1-3b: If the PRACH or the last symbol of the PRACH is in slot m, the terminal 20 and the base station 10 determine that the point at which LP-WUS monitoring is not required is the time point at the end of slot m+s3.

[0135] <Option 2> In option 2, a response from the base station 10 to the fallback notification is required in order for the terminal 20 and the base station 10 to determine at what time point the LP-WUS monitoring is no longer required. After receiving the response, the terminal 20 determines that LP-WUS monitoring is no longer required at the time when LP-WUS monitoring is no longer required, and falls back to PDCCH monitoring.

[0136] The operation of option 2 will be described with reference to Fig. 4. In S301, terminal 20 transmits a fallback notification to base station 10. In S302, terminal 20 receives a response transmitted from base station 10. In S303, terminal 20 determines that LP-WUS monitoring is not necessary when LP-WUS monitoring is not necessary, and falls back to PDCCH monitoring. Note that base station 10 may also determine the time when LP-WUS monitoring is not necessary using the same determination as terminal 20. More specific options in option 2 will be described below.

[0137] Option 2-1: The terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is no longer required is the time position of the end of the last symbol of the PDCCH having an UL grant triggered by SR. Option 2-1 is suitable for Alt. 1 of the first embodiment.

[0138] Option 2-1a: The terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time point at the end of n1 symbols after the last symbol of the PDCCH.

[0139] Option 2-1b: If the PDCCH or the last symbol of the PDCCH is in slot m, the terminal 20 and the base station 10 determine that the point in time when LP-WUS monitoring is not required is the time point at the end of slot m+s1.

[0140] Option 2-2: The terminal 20 and the base station 10 determine that the time point at which the terminal 20 transmits the fallback notification (the last symbol of the PDCCH having a new PUSCH transmission scheduling with the same HARQ ID as the PUSCH / the end time of the drx-RetransmissionTimerUL timer for the PUSCH (for transmitting the fallback notification)) is the time point at which LP-WUS monitoring is unnecessary. Option 2-2 is suitable for Alt. 2 / 3 of the first embodiment.

[0141] Option 2-2a: The terminal 20 and the base station 10 determine that the end of n2 symbols after [the last symbol of the above PDCCH / the end of the above drx-RetransmissionTimerUL timer] is the point at which LP-WUS monitoring is not required.

[0142] Option 2-2b: If [the PDCCH or the last symbol of the PDCCH / end of the drx-RetransmissionTimerUL timer] is in slot m, the terminal 20 and the base station 10 determine that the time position at the end of slot m+s2 is the point at which LP-WUS monitoring is not required.

[0143] Option 2-3: The terminal 20 and the base station 10 determine that the time position of the end of the last symbol of the PDSCH of the RAR with respect to the PRACH of the fallback notification is the time when LP-WUS monitoring is not required. Option 2-3 is suitable for Alt.4 of the first embodiment.

[0144] Option 2-3a: The terminal 20 and the base station 10 determine that the end of n3 symbols after the end of the last symbol of the PDSCH (the end of n3 symbols after the end of the last symbol of the above PDS) is the time when LP-WUS monitoring is not required.

[0145] Option 2-3b: If the PDSCH or the last symbol of the PDSCH is in slot m, the terminal 20 and the base station 10 determine that the time position at the end of slot m+s3 is the time when LP-WUS monitoring is not required.

[0146] Option 2-4: The terminal 20 and the base station 10 determine that the time position of the end of the last symbol of the PUCCH / PUSCH having the HARQ ACK for the RRC message from the base station 10 in response to the fallback notification is the time point at which LP-WUS monitoring is not required. Options 2-4 are suitable for Alt.3 of the first embodiment.

[0147] Option 2-4a: The terminal 20 and the base station 10 determine that the end of n4 symbols after the last symbol of the PUCCH / PUSCH is the point at which LP-WUS monitoring is not required.

[0148] Option 2-4b: If the PUCCH / PUSCH or the last symbol of the PUCCH / PUSCH is in slot m, the terminal 20 and the base station 10 determine that the time position at the end of slot m+s4 is the time when LP-WUS monitoring is not required.

[0149] The parameters such as n1 used in the third embodiment are defined, for example, as follows:

[0150] ·ni / si / m are integers greater than or equal to 0, where i=1,2,3,.

[0151] · ni / si may or may not consider the wake-up delay of MR.

[0152] For example, si=3N subframe,μ slot +d, where d is the wake-up delay. subframe,μ slot is the number of slots contained in one subframe in μ(SCS), as defined in the existing specifications. subframe,μ slot is based on the SCS of one of the following Alts, for example:

[0153] Alt.a: The SCS of the active BWP in which the terminal 20 transmits the above-mentioned SR / PRACH / PUSCH.

[0154] Alt.b: SCS of an active BWP in which the terminal 20 receives the PDCCH / PDSCH.

[0155] Alt.c: The smaller / larger SCS of Alt.a and Alt.b.

[0156] <Effects of the third embodiment> According to the third embodiment, after the terminal 20 sends a fallback notification, the terminal 20 (and the base station 10) can clearly determine the time point at which the terminal 20 no longer needs to monitor the LP-WUS.

[0157] (Common to the first to third embodiments)

[0158] In this embodiment, the terminal 20 may report to the network (for example, the base station 10) capability information (UE capability) of the terminal 20. The capability information may include, for example, at least one of the following:

[0159] - Capabilities related to each of the above-mentioned embodiments (information indicating that each embodiment is supported) - Capabilities related to each option or combination of options in each embodiment - Capabilities related to each Alt. or combination of Alt. in each embodiment The terminal 20 may report the capability information in frequency units, which may include at least one of UE units, FR1, FR2, FR2-1, FR2-2, FR3, subcarrier spacing (SCS), frequency band, BC, FC, or FSPC units.

[0160] The terminal 20 may report the above capability information on a cell-by-cell basis, which may include at least one of a UE unit, a cell unit, or a TDD or FDD unit.

[0161] In this embodiment, the terminal 20 may receive the following types of information from the network (eg, the base station 10):

[0162] - Information via higher layer signaling (e.g., RRC messages / LPP messages) - MAC CE The MAC CE may be a MAC CE having a new LCID in the subheader, or may be a MAC CE that is an extension of an existing MAC CE (for example, a MAC CE in which a new octet is introduced).

[0163] - DCI The DCI field may be an existing DCI field or a newly introduced DCI field. The DCI may be a DCI in which the CRC is scrambled with the existing RNTI or a newly introduced RNTI. The DCI format may be an existing DCI format or a newly introduced DCI format. A combination of these may be applied to the DCI.

[0164] In this embodiment, the terminal 20 may receive information from the network periodically, semi-persistently (triggered by instructions from the terminal 20 or the base station 10) or aperiodically (triggered by instructions from the terminal 20 or the base station 10).

[0165] (Device configuration) Next, a description will be given of an example of the functional configuration of the base station 10 and the terminal 20 that execute the processes and operations described above. The base station 10 and the terminal 20 include functions for implementing all of the above-described embodiments. However, the base station 10 and the terminal 20 may each include only some of the functions of all of the embodiments.

[0166] <Base station 10> Fig. 5 is a diagram showing an example of the functional configuration of the base station 10 in this embodiment. As shown in Fig. 5, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 5 is merely an example. The names of the functional divisions and functional units may be any as long as they can perform the operations in this embodiment. The transmitting unit 110 and the receiving unit 120 may be collectively referred to as a communication unit.

[0167] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signal. The transmitter 110 also has a function of transmitting PSS, SSS, PBCH, DL / UL control signals, LP-WUS, etc. to the terminal 20. The receiver 120 also receives inter-network node messages from other network nodes.

[0168] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20. The content of the setting information is, for example, information on the operations described in each embodiment.

[0169] The control unit 140 controls settings, instructions, and notifications related to the operations described in the embodiments. The function unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the function unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0170] <Terminal 20> Fig. 6 is a diagram showing an example of the functional configuration of the terminal 20 in this embodiment. As shown in Fig. 6, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 6 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations in this embodiment. The transmitting unit 210 and the receiving unit 220 may be collectively referred to as a communication unit.

[0171] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The transmitter 210 also transmits capability information in a low-power wake-up signal to the base station 10. The receiver 220 wirelessly receives various signals and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving PSS, SSS, PBCH, DL / UL / SL control signals, LP-WUS, and the like transmitted from the base station 10. The setting unit 230 stores various setting information received by the receiver 220 from the base station 10. The setting unit 230 also stores setting information that is set in advance. The content of the setting information is, for example, information on the operations described in the embodiments.

[0172] As described in each embodiment, the control unit 240 controls the settings, instructions, and notifications related to the operations described in the examples. A functional unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0173] (Hardware configuration) The block diagrams (FIGS. 5 and 6) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by hardware, software, or a combination of these. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized by using one device that is physically or logically coupled, or may be realized by using two or more physically or logically separated devices that are connected directly or indirectly (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the one device or the multiple devices with software.

[0174] For example, a base station, a terminal, a network node, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 7 is a diagram showing an example of the hardware configuration of a base station and a terminal according to an embodiment of the present disclosure. The above-described base station 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0175] In the present disclosure, the term "apparatus" may be interchangeable with any two terms selected from a set of terms such as circuit, device, unit, module, chip, means, etc. The hardware configurations of the base station 10 and the terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0176] Each function in the base station 10 and the terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001, memory 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls the reading, writing, or both reading and writing of data in the memory 1002 and storage 1003.

[0177] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, a baseband signal processing unit, a call processing unit, etc. may be realized by the processor 1001. Although only one processor 1001 is shown in the figure, there may be multiple processors.

[0178] The processor 1001 also reads programs (program codes), software modules, data, etc. from the storage 1003, the communication device 1004, or both the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 401 of the terminal 20 may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and similar implementations may be made for other functional blocks. While the above-described various processes have been described as being executed by a single processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line, or may be provided to the computer via the communication device 1004, for example.

[0179] The present disclosure also provides a computer program product including a computer program, which may implement the steps of the methods described in the above embodiments when the computer program is executed by a computer (e.g., the processor 1001).

[0180] The memory 1002 is a computer-readable recording medium and may be configured, for example, as a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), or a combination of at least two of these. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), or the like. The memory 1002 can store executable programs (program codes), software modules, and the like for implementing a wireless communication method according to an embodiment of the present disclosure.

[0181] Storage 1003 is a computer-readable recording medium, and may be, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, or a combination of at least two of these. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, memory 1002, storage 1003, or a database, server, or other appropriate medium including both memory 1002 and storage 1003.

[0182] The communication device 1004 is hardware (transmitting / receiving device) for communicating between computers via a wired network, a wireless network, or both wired and wireless networks, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, or a combination of at least two of these. For example, a transmitting / receiving antenna, an amplifier unit, a transmitting / receiving unit, or a transmission path interface may be realized by the communication device 1004. The transmitting / receiving unit may be implemented as a transmitting unit and a receiving unit that are physically or logically separated.

[0183] The input device 1005 is an input device that accepts input from the outside (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, or a combination of at least two of these). The output device 1006 is an output device that outputs to the outside (for example, a display, a speaker, an LED lamp, or a combination of at least two of these). The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0184] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0185] Furthermore, base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a graphics processing unit (GPU), a neural processing unit (NPU), or a combination of at least two of these, and some or all of the functional blocks may be realized by the hardware. For example, processor 1001 may be implemented using at least one of these pieces of hardware.

[0186] <Additional notes> (Additional note 1) a control unit that determines whether to perform a fallback from a state in which low-power signals are monitored to a state in which a control channel is monitored; a transmitter for transmitting a fallback notification to a base station; A terminal comprising: (Additional note 2) The transmission unit transmits a scheduling request, a MAC CE (Medium Access Control Element), an RRC (Radio Resource Control) message, or a PRACH (Physical Random Access Channel) to the base station as the fallback notification. A terminal as described in appendix 1. (Additional note 3) When the control unit determines that the fallback notification has not been received by the base station, the transmitter retransmits the fallback notification to the base station. The control unit maintains a state in which it monitors the low-power signal, or The transmitting unit performs random access. A terminal as described in appendix 1. (Additional note 4) After the transmitter transmits the fallback notification to the base station, the controller determines that there is no need to monitor the low power signal at a time position of a specific symbol related to the transmission of the fallback notification. A terminal as described in appendix 1. (Additional note 5) After the transmitter transmits the fallback notification to the base station, the controller determines that there is no need to monitor the low power signal at a time position of a specific symbol associated with receiving a response to the fallback notification from the base station. A terminal as described in appendix 1. (Additional note 6) A communication method executed by a terminal, comprising: determining to perform a fallback from monitoring a low power signal to monitoring a control channel; sending a fallback notification to a base station; A communication method comprising:

[0187] Any of the above configurations can avoid mismatching of recognition between the terminal and the base station when the terminal falls back from a state of monitoring LP-WUS to a state of monitoring PDCCH. According to Supplementary Item 2, various signals can be used as fallback notification. According to Supplementary Item 3, even if it is determined that the base station 10 has not received a fallback notification, it can continue to operate appropriately. According to Supplementary Item 4, the terminal can clearly determine the point in time when it is no longer necessary to monitor low-power signals.

[0188] (Supplementary explanation of the embodiment) Although the present embodiment has been described above, the disclosed invention is not limited to such an embodiment, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of the processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the base station 10 according to this embodiment and the software operated by the processor of the terminal 20 according to this embodiment may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0189] The aspects / embodiments described in the present disclosure may be categorized as Long Term Evolution (LTE), LTE-Advanced (LTE-A), International Mobile Telecommunications-Advanced (IMT-Advanced), 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 5G-Advanced (5G-A), 6th generation mobile communication system (6G), xth generation mobile communication system (x is, for example, an integer or a decimal number)), Future Radio Access (FRA), New Radio (NR), New radio access (NX), Future generation radio access (FX), Open Radio Access Network (O-RAN), Wideband Code Division Multiple Access (W-CDMA) (registered trademark), Global System for Mobile communications (GSM) (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) Engineers) 802.11, IEEE802.11x (where x is any character string such as b, a, g, n, ac, ax, be, or bn, and when x=n it is called Wi-Fi4, when x=ac it is called Wi-Fi5, when x=ax it is called Wi-Fi6 or Wi-Fi6E, when x=be it is Wi-Fi7, and when x=bn it is called Wi-Fi8, etc. Wi-Fi is a registered trademark.), IEEE802.16 (WiMAX (registered trademark), IEEE802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), network virtualization technology (e.g., NFV (Network Function Virtualization), SFC (Service Function Chaining), SDN (Software Defined Networking)), or LPWA (Low Power Wide Area). Furthermore, each aspect / embodiment described in the present disclosure may be applied to a system based on a combination of at least two of these technologies. Furthermore, "based on" naturally refers not only to a system that uses the technology, but also to a system that uses an extension or modification of the technology.

[0190] In the present disclosure, any two terms selected from a set of terms such as "base station (BS)", "radio base station", "fixed station (fixed station)", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point (AP)", "transmission point (TP)", "reception point (RP)", "transmission / reception point (TRP)", "radio unit (RU)", "remote unit (RU)", "control unit (CU)", "distributed unit (DU)", "remote radio head (RRH)", "node", "gateway", "terrestrial base station", "stratospheric base station", "unmanned aerial vehicle", "high altitude platform station (HAPS)", "airborne platform", "panel", "cell", "radio access network (RAN)", and "network" may be used interchangeably.

[0191] Each cell accommodated by a base station may be referred to by terms such as a macro cell, a small cell, a femto cell, a pico cell, a serving cell, or a super cell. In the present disclosure, any two terms selected from a set of terms such as "cell," "sector," "cell group," "carrier," "component carrier," "cluster," "bandwidth part (BWP)," and "carrier bandwidth" may be used interchangeably.

[0192] In the present disclosure, any two terms selected from the set of terms such as "Mobile Station (MS)", "user terminal", "User Equipment (UE 20)", "Device", "Module" and "Terminal" may be used interchangeably.

[0193] A terminal may be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, router (e.g., home router, mobile router, etc.), TCU (Telematics Control Unit), or some other suitable terminology.

[0194] The base station and the terminal may each be composed of one or more devices. The devices constituting at least a portion of the base station and the terminal may be called a transmitting device, a receiving device, a communication device, etc. Note that the devices constituting at least a portion of the base station and the terminal may be, for example, an object itself, such as a vehicle, a transport vehicle, an automobile, a motorcycle, a bicycle, a connected car, an excavator, a bulldozer, a wheel loader, a dump truck, a forklift, a train, a bus, a handcar, a rickshaw, a ship and other watercraft, an airplane, a rocket, an unmanned aerial vehicle, a stratospheric base station (e.g., a High Altitude Platform Station (HAPS)), an artificial satellite (e.g., a Low Earth Orbit (LEO) satellite, a Medium Earth Orbit (MEO) satellite, a Geostationary Earth Orbit (GEO) satellite), a drone (registered trademark), a multicopter, a quadcopter, a balloon, or an Internet of Things (IoT) device (e.g., a smart meter, a sensor), or may include, but are not limited to, an object or device mounted on the object. Furthermore, the object may be a moving object (hereinafter referred to as a "moving object"; this does not exclude the case where the moving object is in a stationary state where it is not moving), or may be a fixedly positioned object (hereinafter referred to as a "non-moving object").

[0195] Furthermore, a base station in the present disclosure may be read as a terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)) or communication of a non-terrestrial network (NTN). In this case, the terminal 20 may be configured to have at least some of the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "sidelink") or terms corresponding to NTN (for example, feeder link or service link). For example, an uplink channel or a downlink channel may be read as a sidelink channel.

[0196] The present disclosure is also applicable to cases where at least some of the devices constituting the base station and the terminal operate outside the earth (for example, in the atmosphere or outer space).

[0197] In addition, the term "terminal" in the present disclosure may be read as "base station." In this case, the base station 10 may be configured to have the functions of the terminal 20 described above.

[0198] The notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB))), other signals, or a combination of at least two of these. Note that the physical layer signaling may be referred to as Layer 1 (L1) control information. The MAC signaling may be referred to as a MAC Control Element (CE) or a MAC Protocol Data Unit (PDU), for example. Furthermore, the RRC signaling may be referred to as an RRC message or an information element (IE) in the RRC message. The RRC message may be, for example, a message used for controlling an RRC connection (for example, setup, reconfiguration, establishment, reestablishment, release, or resume), mobility, a measurement report, or notification of a terminal's capabilities, or may be an information element within the message. Furthermore, notification of information may be explicit or implicit. Note that explicit notification of certain information means notification of the certain information itself, and implicit notification of certain information may mean notification of information other than the certain information, or may mean that the certain information is considered to have been notified when a certain condition is satisfied.Furthermore, notification of information may include not only notification between the same layers of different devices (e.g., between a lower layer or an upper layer of the base station 10 and the terminal 20) but also notification between different layers in the same or different devices (e.g., between a lower layer and an upper layer in the base station 10 or the terminal 20). Furthermore, notification of information from one device to another device may be performed via one or more devices. Regarding any information (e.g., a variable, a constant, a parameter, a setting) described in the present disclosure, even if not specifically stated in the above embodiments, information indicating / specifying (or related to) the any information (value) may be notified from any first device (e.g., a terminal / base station) to any second device (e.g., a base station / terminal).

[0199] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0200] In the present disclosure, a specific operation described as being performed by a base station may be performed by its upper node or by some of its upper nodes (e.g., CU, RU, or DU, etc.) in some cases. It is clear that various operations performed for communication with a terminal in a RAN or core network may be performed by at least some of the base station and other network nodes other than the base station. The other network node may be one node or a combination of multiple nodes. The network node is, for example, a node provided in various core networks such as EPC (Evolved Packet Core) and 5GC (5G Core Network), and provides one or more network functions (NF: Network Functions), but is not limited to this.

[0201] Furthermore, in the present disclosure, the operation of "a terminal receives information from a base station" accompanies the operation of "the base station transmits the information to the terminal," "the base station generates the information," or both. Similarly, the operation of "a terminal transmits information to a base station" accompanies the operation of "the base station receives the information from the terminal." Furthermore, the operation of "the terminal is configured to ..." or "configure UE 20 to ..." may include the operation of "the base station transmits configuration information regarding the configuration of the terminal" and the operation of "the terminal configures a predetermined operation based on the configuration information."

[0202] Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched depending on the implementation.

[0203] The present disclosure has been described above, but it is for illustrative purposes only, and the present invention is not limited to the aspects / embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit of the invention. The present disclosure and its modifications and alterations are included in the scope of the present invention and its equivalents.

[0204] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0205] The radio resource may be defined by a combination of resource units in one or more domains, such as the time domain, the frequency domain, the spatial domain, the code domain, and the power domain.

[0206] For example, resources in the time domain may be defined by one or more time units. The one or more time units may include, but are not limited to, a radio frame, a subframe, a slot, a symbol, a transmission time interval (TTI), or a combination of at least two of these. The time unit may be a fixed-length time unit independent of numerology, a variable-length time unit dependent on numerology, or both. Examples of fixed-length time units include, but are not limited to, a subframe consisting of one or more slots and a radio frame including multiple subframes. Examples of variable-length time units include, but are not limited to, a symbol and a slot including a fixed number of symbols. A certain time unit may be divided into shorter time units. Examples of shorter time units include, but are not limited to, a minislot consisting of fewer symbols than the number of symbols constituting a slot. The above-described time units may include, for example, time units used as units for scheduling, link adaptation, etc. Furthermore, any time unit in the present disclosure may be read as another time unit.

[0207] Numerology is a parameter that defines the physical layer structure, and may be a parameter based on at least one of subcarrier spacing (SCS), symbol length, cyclic prefix length, and sampling time, for example.

[0208] Resources in the frequency domain may be defined, for example, by one or more frequency units. The one or more frequency units may include, for example, subcarriers, resource blocks (RBs), bandwidth parts (BWPs), carrier bandwidths, or a combination of at least two of these, but the terminology of the frequency units is not limited to these. The number of subcarriers included in a frequency unit may be a fixed number regardless of numerology, or may be a variable number that changes depending on numerology. For example, an RB is composed of a predetermined number of consecutive subcarriers in the frequency domain, and the number of subcarriers included in the RB may be the same regardless of numerology, for example, 12, but is not limited to this. A BWP may be composed of, for example, one or more consecutive RBs within a certain carrier bandwidth, but is not limited to this. One or more BWPs may be configured within one carrier for terminal 20, and at least one of the BWPs may be activated. Any frequency unit in the present disclosure may be interchangeable with another frequency unit.

[0209] Furthermore, resources in both the time domain and the frequency domain may be defined by one or more time / frequency units each consisting of a time unit and a frequency unit, such as, but not limited to, a resource element (RE) consisting of one symbol and one subcarrier, a resource element group (REG) consisting of a predetermined number of REs, or a control resource set (CORESET) consisting of a predetermined number of symbols and a predetermined number of RBs.

[0210] Furthermore, resources in the spatial domain may be defined, for example, by one or more spatial units, including, but not limited to, a beam, a layer of MIMO (Multi-Input Multi-Output), an antenna port, or a combination of at least two of these.

[0211] Furthermore, the resources in the code domain may be defined by one or more code units, such as, but not limited to, a cyclic shift (CS), an orthogonal cover code (OCC), or a combination thereof.

[0212] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0213] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc. [Explanation of symbols]

[0214] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 terminals 210 Transmitter 220 Receiving unit 230 Setting Section 240 Control Unit 1001 processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output Device

Claims

1. a control unit that determines whether to perform a fallback from a state in which low-power signals are monitored to a state in which a control channel is monitored; a transmitter for transmitting a fallback notification to a base station; A terminal comprising:

2. The transmission unit transmits a scheduling request, a MAC CE (Medium Access Control Element), an RRC (Radio Resource Control) message, or a PRACH (Physical Random Access Channel) to the base station as the fallback notification. The terminal according to claim 1 .

3. When the control unit determines that the fallback notification has not been received by the base station, the transmitter retransmits the fallback notification to the base station. The control unit maintains a state in which it monitors the low-power signal, or The transmitting unit performs random access. The terminal according to claim 1 .

4. After the transmitter transmits the fallback notification to the base station, the controller determines that there is no need to monitor the low power signal at a time position of a specific symbol related to the transmission of the fallback notification. The terminal according to claim 1 .

5. After the transmitter transmits the fallback notification to the base station, the controller determines that there is no need to monitor the low power signal at a time position of a specific symbol associated with receiving a response to the fallback notification from the base station. The terminal according to claim 1 .

6. A communication method executed by a terminal, comprising: determining to perform a fallback from monitoring a low power signal to monitoring a control channel; sending a fallback notification to a base station; A communication method comprising:

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