Terminal and wireless communication method

Abstract

To provide a terminal and a wireless communication method that appropriately control operations related to a TRS.SOLUTION: In a wireless communication system, a terminal 10 includes a receiving unit 101 that receives first indication information indicating that a tracking reference signal is available in a resource and / or period set for the tracking reference signal, and a control unit 103 that starts a timer related to a valid period of the first indication information. The control unit 103 stops the timer if the receiving unit 101 receives second indication information indicating that the tracking reference signal is not available in the resource and / or period while the timer is activated.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present disclosure relates to a terminal and a wireless communication method.

Background Art

[0002] In the Third Generation Partnership Project (3GPP), which is an international standards organization, Release 15 of New Radio (NR), which is a fifth-generation (5G) Radio Access Technology (RAT), has been standardized as a successor to Long Term Evolution (LTE), which is a 3.9-generation RAT, and LTE-Advanced, which is a fourth-generation RAT (for example, Non-Patent Document 1). LTE and / or LTE-Advanced are also referred to as Evolved Universal Terrestrial Radio Access (E-UTRA).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Currently, in 3GPP, using a reference signal for tracking (hereinafter referred to as "Tracking Reference Signal (TRS)") to perform synchronization in the time domain and / or frequency domain (hereinafter referred to as "time / frequency synchronization") and the like are being considered. For example, it is expected that a terminal in the idle state or inactive state uses the TRS instead of the synchronization signal to perform time / frequency synchronization before a paging occasion (PO), thereby reducing the power consumption of the terminal.

[0005] Also, it is being considered to notify the terminal of indication information (hereinafter referred to as "TRS availability indication") regarding the availability of the TRS in the resources and / or periods set for the TRS, and / or to provide a validity period for the indication information, so as to be able to control whether to actually transmit the TRS in the resources and / or periods.

[0006] This disclosure has been made in view of such circumstances, and one of the objectives is to provide a terminal and a wireless communication method capable of appropriately controlling operations related to the TRS.

Means for Solving the Problems

[0007] A terminal according to an aspect of the present disclosure includes a receiving unit that receives first indication information indicating that the tracking reference signal is available in resources and / or periods set for the tracking reference signal, and a control unit that starts a timer regarding the validity period of the first indication information. The control unit stops the timer when the receiving unit receives second indication information indicating that the tracking reference signal is not available in the resources and / or periods while the timer is running.

Effects of the Invention

[0008] According to one aspect of the present disclosure, one of the objectives is to provide a terminal and a wireless communication method capable of appropriately controlling operations related to TRS.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, this embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same reference numerals are attached to the same components in each drawing as much as possible, and duplicate descriptions are omitted.

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

[0012] As the radio access technology (RAT) of the wireless communication system 1, for example, NR is assumed, but it is not limited thereto, and various RATs such as RATs after the sixth generation can be used.

[0013] The terminal 10 is a predetermined terminal or device such as a smartphone, a personal computer, an in-vehicle terminal, an in-vehicle device, a stationary device, or a telematics control unit (TCU). The terminal 10 may 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 mobile or fixed. The terminal 10 is configured to be able to communicate using, for example, NR as the RAT.

[0014] The base station 20 forms one or more cells C and communicates with the terminal 10 using the cells. The cell C may be interchangeably referred to as a serving cell, a carrier, a component carrier (CC), etc. For example, the base station 20 may set and communicate with the terminal 10 one primary cell and one or more secondary cells (also referred to as carrier aggregation). That is, one or more cells C include at least a primary cell and may include a secondary cell.

[0015] Also, one or more bandwidth parts (BWPs) may be set for one cell C. Here, the BWP mainly used when the terminal 10 initially accesses the cell is also referred to as the initial downlink BWP and the initial uplink BWP. For example, the base station 20 may include in the system information the information used to set the frequency position, bandwidth, subcarrier spacing, and / or cyclic prefix for each of the initial downlink BWP and the initial uplink BWP and notify it.

[0016] The base station 20 may be called a gNodeB (gNB), an en-gNB, a Next Generation-Radio Access Network (NG-RAN) node, 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, etc. The base station 20 is not limited to one node and may be composed of a plurality of nodes (for example, a combination of a lower node such as a DU and an upper node such as a CU).

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

[0018] The core network device may include, for example, at least one of an Access and Mobility Management Function (AMF) that manages C-plane information (for example, information related to access and mobility management, etc.), and a User Plane Function (UPF) that performs transmission control of U-plane information (for example, user data).

[0019] In the wireless communication system 1, the terminal 10 receives a downlink (DL) signal from the base station 20 and / or transmits an uplink (UL) signal. One or more cells C are configured for the terminal 10, and at least one of the configured cells is activated. The maximum bandwidth of each cell is, for example, 20 MHz or 400 MHz, etc.

[0020] Also, the terminal 10 performs cell search based on synchronization signals from the base station 20 (for example, Primary Synchronization Signal (PSS) and / or Secondary Synchronization Signal (SSS)). Cell search is a procedure in which the terminal 10 acquires time and frequency synchronization in the cell and detects the identifier of the cell (for example, physical layer cell ID).

[0021] A block containing at least one of the above synchronization signal, notification channel (e.g., Physical Broadcast Channel (PBCH)), and Demodulation Reference Signal (DMRS) for the notification channel is also called a Synchronization Signal Block (SSB), an SS / PBCH block, etc. One or more SSBs may constitute one SS burst, and one or more SS bursts may constitute one SS burst set. The SS burst set may be transmitted at a predetermined period (e.g., 20 ms (2 radio frames)). In the case of multi-beam operation, SSBs with different indexes may correspond to different beams and may be transmitted by sequentially switching the beam direction through beam sweeping.

[0022] Based on the parameters (hereinafter referred to as "RRC parameters") included in the Radio Resource Control (RRC) message, the terminal 10 determines a search space and / or a Control Resource Set (CORESET), and monitors the downlink control information (DCI) transmitted via a downlink control channel (e.g., Physical Downlink Control Channel (PDCCH)) within the search space associated with the CORESET. Note that the RRC message may include, for example, an RRC setup message, an RRC reconfiguration message, an RRC resume message, system information, etc.

[0023] Monitoring of DCI means that the terminal 10 blindly decodes PDCCH candidates in the search space set in the assumed DCI format. The number of bits of the DCI format (also referred to as size, bit width, etc.) is predetermined or derived according to the number of bits of the fields included in the DCI format. The terminal 10 detects DCI for the terminal 10 based on the number of bits of the DCI format and a specific Radio Network Temporary Identifier (RNTI) used for scrambling of the Cyclic Redundancy Check (CRC) bits (also referred to as CRC parity bits) of the DCI format (hereinafter referred to as "CRC scrambling"). Monitoring of DCI is also called PDCCH monitoring, monitoring, etc. Also, the period during which DCI is monitored is also called a PDCCH monitoring occasion.

[0024] A search space set is a set of one or more search spaces and may include a common search space set (hereinafter referred to as "Common search space: CSS set") that is commonly used by one or more terminals 10 and a UE-specific search space set (USS set). The search space set used for PDCCH monitoring of the terminal 10 may be set for the terminal 10 using upper layer parameters (e.g., RRC Information Element (IE) "SearchSpace", RRC IE "pagingSearchSpace", RRC IE "searchSpaceSIB1", RRC IE "searchSpaceOtherSystemInformation", etc.). The terminal 10 detects DCI scrambled by a specific RNTI (e.g., Cell (C)-RNTI, Paging (P)-RNTI, etc.) through PDCCH monitoring using the search space set, and controls the reception of PDSCH scheduled using the DCI and / or the transmission of an uplink shared channel (e.g., Physical Uplink Shared Channel: PUSCH).

[0025] (System Information) The system information broadcast in cell C may include a Master Information Block (MIB) and / or one or more System Information Blocks (SIBs). The MIB is broadcast via the Broadcast Channel (BCH). The MIB and SIB1 are also called Minimum System Information, and SIB1 is also called Remaining Minimum System Information (RMSI). SIB1 is broadcast via the Downlink Shared Channel (DL-SCH). SIBx other than SIB1 (where x is any string such as 2, 3, etc.) is also called Other System Information (OSI). SIB1 is cell-specific, and SIBx other than SIB1 is cell-specific or area-specific including one or more cells. The area is also called a system information area, etc.

[0026] One or more SIBx are mapped to a System Information (SI) message, and the SI message is broadcast via the DL-SCH. Each SI message is associated with a periodically occurring time domain window (hereinafter referred to as the "SI window") and may be transmitted within the SI window. Note that BCH and DL-SCH may be mutually rephrased as PBCH and Physical Downlink Shared Channel (PDSCH), respectively.

[0027] FIG. 2 is a diagram showing an example of acquisition of SI messages according to the present embodiment. In FIG. 2, as an example, it is assumed that SIBx and SIBy are mapped to SI message #0, and SIBz is mapped to SI message #1. Here, x, y, and z are each an arbitrary character string such as 2, 3, …, and may be an identifier of the type of SIB (hereinafter referred to as “SIB type”). SI messages #0 and #1 may be notified at a predetermined period, or may be notified on demand in response to a request from terminal 10. Also, each SI message #0 may be the same within the modification period. Note that FIG. 2 is merely an example, and the number of SI messages, the number of SIBs mapped to each SI message, whether SIBx, SIBy, and SIBz are area-specific or cell-specific, etc. are not limited to those illustrated.

[0028] For example, as shown in FIG. 2, terminal 10 detects an SSB and acquires the MIB notified via the PBCH. Terminal 10 monitors a search space set (for example, a Type0-PDCCH CSS set) configured for SIB1 to detect DCI scrambled with a specific RNTI (for example, a System Information (SI)-RNTI), and receives SIB1 via the PDSCH scheduled by the DCI. The search space set for SIB1 may be configured based on parameters in the MIB, but is not limited thereto.

[0029] Also, SIB1 may include at least one of the following. · Information regarding each SI message (for example, each “schedulingInfo” in the RRC IE “schedulingInfoList”) · Identification information of the area to which the area-specific SIB belongs (for example, “systemInformationAreaID” of the RRC IE) · Information regarding the length of the SI window (for example, “si-WindowLength” of the RRC IE), where the length is indicated by, for example, the number of slots. · Information regarding the period of each SI message (e.g., "si-Periodicity" in the RRC IE "schedulingInfo"), where the period is indicated by, for example, the number of radio frames. · Information regarding each SIB mapped to each SI message (e.g., each "SIB-TypeInfo" in "SIB-Mapping" within the RRC IE "schedulingInfo"), where the information regarding each SIB may include at least one of, for example, information regarding the SIB type (e.g., the RRC IE "type"), information regarding the version or update count of each SIB (hereinafter referred to as "version information", e.g., the RRC IE "valueTag"), and information indicating that each SIB is area-specific (e.g., the RRC IE "areaScope"). Note that not including the information indicating that each SIB is area-specific may indicate that each SIB is cell-specific.

[0030] The terminal 10 monitors a search space set configured for OSI (e.g., Type0A-PDCCH CSS set), detects DCI scrambled with a specific RNTI (e.g., SI-RNTI), and receives SI messages #0 and #1 via the PDSCH scheduled by the DCI, and performs operations based on the OSI (here, SIBx, SIBy, and SIBz) included in each of SI messages #0 and #1.

[0031] For example, in FIG. 2, SIBx and SIBy included in SI message #0 are area-specific, and SIBz included in SI message #1 is cell-specific. Also, the version information of SIB1 (e.g., RRC IE "valueTag") indicates that SIBx and SIBz are updated once and the version is v1, while SIBy is not updated and the version is v0. For example, the terminal 10 may determine whether the stored SIBx is valid based on the version indicated by the version information and the version of SIBx stored in the own terminal 10. For example, when the "v1" indicated by the valueTag in SIB1 matches the version of the stored SIBz, the terminal 10 may not need to receive SI message #1 including SIBz again. On the other hand, when the version "v1" indicated by the valueTag in SIB1 does not match the version of the stored SIBx, the terminal 10 may receive SI message #0 including SIBx again. In this way, for each change in the content of SIBx, SIBy, and SIBz, the valuetag may be incremented by 1.

[0032] (Paging) In paging, when the terminal 10 is in the idle state or the inactive state, a message (hereinafter, "paging message") for setting up a connection under network control is transmitted to the terminal 10. Also, in paging, for example, a short message used for a change notification of system information and / or a public warning (e.g., Earthquake and Tsunami Warning System (ETWS), Commercial Mobile Alert Service (CMAS), etc.) is transmitted to the terminal 10. The short message may be transmitted to the terminal 10 regardless of the state of the terminal 10 (e.g., idle state, inactive state, or connected state, etc.).

[0033] Here, the idle state is a state in which the RRC layer connection (hereinafter referred to as the "RRC connection") between the terminal 10 and the base station 20 is not established, and is also called RRC_IDLE, idle mode, RRC idle mode, etc. The terminal 10 in the idle state receives the system information notified by the cell on which it camps. When the RRC connection of the terminal 10 in the idle state is established, it transitions to the connected state.

[0034] In addition, the inactive state is a state in which the above RRC connection is established but suspended, and is also called the RRC_INACTIVE state, inactive mode, RRC inactive mode, etc. The terminal 10 in the inactive state receives the system information notified by the cell on which it camps. When the RRC connection of the terminal 10 in the inactive state is resumed, it transitions to the connected state, and when the RRC connection is released, it transitions to the idle state.

[0035] The connected state is a state in which the above RRC connection is established, and is also called the RRC_CONNECTED state, connected mode, RRC connected mode, etc. When the RRC connection of the terminal 10 in the connected state is released, it transitions to the idle state, and when the RRC connection is suspended, it transitions to the inactive state.

[0036] The terminal 10 in the idle state or the inactive state receives a paging message at a paging opportunity (PO) which is a period of a predetermined cycle by discontinuous reception (DRX). The PO is associated with a paging frame (PF) of a predetermined cycle. The PF may be composed of radio frames identified by a specific number (for example, a system frame number (SFN)), for example. The PO may be composed of, for example, a subframe, a slot, or symbols of a predetermined cycle.

[0037] Here, the radio frame is composed of 10 subframes, and one subframe may be 1 ms. A slot is a time unit based on a new numerology (e.g., subcarrier spacing (SCS)), and for example, when SCS = 15 kHz, one slot may be equal to one subframe. One slot may include a predetermined number of symbols (e.g., 14 symbols).

[0038] For example, for the terminal 10, PF may be set at a period determined based on the DRX period (hereinafter referred to as the "paging cycle"), and one PO may be set for each PF. That is, a PO may be set for the terminal 10 in the paging cycle. The PO may include one or more PDCCH monitoring opportunities. Hereinafter, the PO is exemplified as the paging period, but of course, the present invention is not limited thereto, and other terms corresponding to the PF or the paging period may be used.

[0039] The terminal 10 may monitor a search space set (e.g., Type2-PDCCH CSS set) set by a higher layer parameter (e.g., RRC IE "pagingSearchSpace") and detect DCI (hereinafter also referred to as "paging DCI") scrambled by a specific RNTI (e.g., paging (P)-RNTI). The terminal 10 receives a paging message via a PDSCH scheduled using the paging DCI. Here, information indicating the specific RNTI (e.g., P-RNTI) may be set for the terminal 10 by higher layer signaling.

[0040] Also, the terminal 10 may receive a short message transmitted by the paging DCI. Thus, the paging DCI is used for scheduling the PDSCH used for transmitting the paging message and / or for transmitting the short message.

[0041] (TRS) Terminal 10 is considered to perform time / frequency synchronization using TRS. For example, in the idle state or the non-active state, terminal 10 enters a sleep state with reduced power consumption in principle between POs due to DRX, but enters a wake-up state for time / frequency synchronization during a predetermined period before the next PO. Specifically, it is assumed that terminal 10 enters a deep sleep state from the previous PO until the predetermined period, and enters a micro sleep state from the predetermined period until the next PO.

[0042] Here, the deep sleep state is a state with even lower power consumption than the micro sleep state. For example, when performing time / frequency synchronization using a TRS arranged at a time position closer to the next PO than the SS burst, the period of the deep sleep state of terminal 10 between POs can be made longer compared to the case of performing time / frequency synchronization using the SS burst. Therefore, reduction of the power consumption of terminal 10 by time / frequency synchronization using TRS is expected.

[0043] Here, the TRS is composed of, for example, a Channel State Information-Reference Signal (CSI-RS), but is not limited thereto. The TRS may be referred to as CSI-RS, Non zero power-CSI-RS (NZP-CSI-RS), TRS / CSI-RS, a reference signal, etc.

[0044] The uses of the TRS may be, for example, at least one of the above time / frequency synchronization, tracking, path delay spread, Doppler spread estimation, and loop convergence. Tracking means tracking and / or compensating for the time and / or frequency variations of the local oscillator of the terminal 10. The TRS may be any signal used for the above uses. Also, when the TRS is set in the terminal 10, the terminal 10 can achieve time / frequency synchronization without referring to the SS burst.

[0045] The resources for the TRS as described above (hereinafter, "TRS resources") may be composed of, for example, a set of one or more resources for NZP-CSI-RS (hereinafter, referred to as "NZP-CSI-RS resources") (hereinafter, "NZP-CSI-RS resource set"). The TRS resources may be composed of a predetermined number of symbols and a predetermined number of subcarriers in a predetermined number of slots with a predetermined period (hereinafter, referred to as "TRS period", for example, a period of 10, 20, 40, or 80 ms). The period of a predetermined cycle including the TRS resources (for example, the above-mentioned predetermined number of slots) is also called a TRS occasion, a TRS / CSI-RS occasion, etc.

[0046] The terminal 10 receives information regarding the TRS resources and / or the TRS occasion (hereinafter, referred to as "TRS resource / occasion information") (hereinafter, referred to as "TRS resource / occasion information"). The terminal 10 may set the TRS resource / occasion based on the TRS resource / occasion information from the base station 20.

[0047] Note that the TRS resource / opportunity information for the terminal 10 in the idle state or inactive state may be at least a part of the TRS resource / opportunity information for the terminal 10 in the connected state. The TRS resource / opportunity information for the terminal 10 in the connected state (for example, RRC IE "NZP-CSI-RS ResourceSet", RRC IE "CSI-ResourceConfig", etc.) may be included in an RRC message (for example, an RRC setup message (RRCSetup message) for establishing an RRC connection or an RRC reconfiguration message (RRCReconfiguration message) for reconfiguring the RRC connection).

[0048] On the other hand, the TRS resource / opportunity information for the terminal 10 in the idle state or inactive state may be included in system information (for example, SIB1 or SIBx), and / or an RRC message (for example, an RRC release message (RRCRelease message) used for releasing or suspending an RRC connection, etc.). For example, the TRS resource / opportunity information for the terminal 10 in the idle state or inactive state may include information related to the power of the TRS (for example, powerControlOffsetSS indicating the power offset of the TRS with respect to the SSS), information related to the scrambling ID of the TRS (scramblingID), information related to the time domain resource to which the TRS is mapped (for example, firstOFDMSymbolInTimeDomain indicating the first symbol for the TRS), and information related to the frequency domain resource to which the TRS is mapped (for example, startingRB indicating the starting resource block of the TRS, nrofRBs indicating the number of resource blocks of the TRS, etc.).

[0049] In addition, the TRS resource / opportunity information for the terminal 10 in the idle state or the non-active state includes information regarding Quasi Co-Location (QCL), and the index of the SSB may be set. That is, the terminal 10 may identify the relationship of quasi co-location between the TRS transmitted in the corresponding TRS resource / opportunity and the SSB by setting the index of the SSB as the TRS resource / opportunity information. Here, quasi co-location may indicate that the large-scale properties of a certain signal (e.g., TRS) can be assumed to be the same as those of another signal (e.g., SSB) in all or part. For example, that two antenna ports are quasi co-located may indicate that the signal (or channel) transmitted at one antenna port can be estimated from the signal (or channel) transmitted at another antenna port. Here, for example, the large-scale properties may include Doppler spread, Doppler shift, delay spread, average gain, and / or average delay.

[0050] Here, the index of the SSB set as the information regarding quasi co-location may be the index of the SSB related to SIB1 (also referred to as Cell-Defining SSB). That is, when information regarding quasi co-location is set for the terminal 10 as the TRS resource / opportunity information for the terminal 10 in the idle state or the non-active state, the index of the SSB related to SIB1 may be set. The terminal 10 may consider that the TRS transmitted in the corresponding TRS resource / opportunity and the SSB are quasi co-located (have a quasi co-location relationship) based on the index of the SSB related to SIB1 set by the base station 20. Here, SIB1 may also be referred to as RMSI (Remaining Minimum System Information).

[0051] Also, at least one parameter used for setting TRS resources / opportunities for the terminal 10 in the idle state or the non-active state may be predefined in the specification. The parameter may be, for example, information related to the BWP (e.g., bwp-id indicating the BWP ID), information related to the TRS resources in the time domain (e.g., resourceType indicating aperiodic, semi-persistent, or periodic), information related to repetition (e.g., repetition indicating on or off of repetition), aperiodicTriggeringOffset indicating the time offset between the trigger of the aperiodic TRS and the TRS resources, trs-Info indicating that all antenna ports of all NZP CSI-RS resources in the CSI-RS resource set are the same, information related to the power of the TRS (e.g., powerControlOffset indicating the power offset of the PDSCH with respect to the NZP-CSI-RS), information related to the number of antenna ports for the TRS (e.g., nrofPorts indicating the number of ports), information related to the time domain resources (e.g., firstOFDMSYmbolInTimeDomain2 indicating the time domain allocation within the resource block), cdm-Type indicating the type of Code Division Multiplexing (CDM) of the TRS, or at least one of information related to the density of the TRS resources (e.g., density). As described above, the TRS here may be equivalently referred to as NZP CSI-RS or the like.

[0052] Also, the TRS resource / opportunity information may include parameters commonly used for settings of a plurality of TRS resources / opportunities and / or parameters used independently. Each of the plurality of TRS resources / opportunities may be assigned an index. For example, an index may be assigned to each of the parameters (e.g., a set of parameters) used independently for settings of the plurality of TRS resources / opportunities. That is, an index may not be assigned to the parameters commonly used for settings of the plurality of TRS resources / opportunities. In this way, the TRS resource / opportunity may be controlled based on upper layer parameters (e.g., RRC parameters and / or MAC CE, etc.) and / or physical layer parameters (e.g., DCI format, etc.).

[0053] It is being considered to signal, from the base station 20 to the terminal 10, instruction information regarding the availability of the TRS in the TRS resource / opportunity as described above (hereinafter referred to as "TRS availability indication"). Note that the availability of the TRS can be mutually paraphrased as the transmission possibility of the TRS in the TRS resource / opportunity and the like. Also, in the following, "(the TRS is actually transmitted or not transmitted from the base station 20)" can be paraphrased as "(the terminal 10 can use or cannot use the TRS)".

[0054] The TRS availability indication is composed of a predetermined number of bits. The first value (e.g., "1") of the bits indicates that the TRS is available (i.e., actually transmitted from the base station 20), and the second value (e.g., "0") of the bits may indicate that the TRS is not available (i.e., not actually transmitted from the base station 20). Also, the predetermined number of bits constituting the TRS availability indication may indicate whether the TRS is available in a specific TRS resource / opportunity (i.e., whether it is actually transmitted from the base station 20). For example, when the TRS resource is composed of an NZP-CSI-RS resource set including NZP-CSI-RS resources #0 to #3, the first bit value (e.g., "000") indicates that the TRS is not transmitted for the entire NZP-CSI-RS resource set, the second bit value (e.g., "001" to "110", etc.) indicates a part of the NZP-CSI-RS resource set and that the TRS is transmitted in the NZP-CSI-RS resource indicated by the second bit value, and the third bit value (e.g., "111") may indicate that the TRS is transmitted for the entire NZP-CSI-RS resource set.

[0055] Also, for example, the base station 20 may set the correspondence between the values set as the TRS availability indication (e.g., each of "000", "001" to "110", etc., and / or "111") and the NZP-CSI-RS resource set using upper layer signaling such as an RRC message. Here, #0 to #3 in the NZP-CSI-RS resources #0 to #3 may correspond to the indexes assigned to the TRS resources / opportunities. For example, as described above, an index is assigned to each of the parameters (e.g., a set of parameters) independently used for the setting of a plurality of TRS resources / opportunities, and the index is indicated corresponding to the TRS availability indication (or, the value of the bit), whereby each of the plurality of TRS resources / opportunities may be identified. That is, the terminal 10 may identify the TRS resource / opportunity based on the parameters commonly used for the setting of a plurality of TRS resources / opportunities and the parameters of the TRS resource / opportunity corresponding to the index indicated by the TRS availability indication (or, the value of the bit). Also, the terminal 10 may determine the TRS availability in the identified TRS resource / opportunity based on the TRS availability indication (or, the value of the bit).

[0056] Alternatively, the TRS availability indication may indicate that the TRS is available (i.e., actually transmitted from the base station 20). For example, the TRS availability indication is notified to (or set to true for) the terminal 10 only when the TRS is actually transmitted from the base station 20 in the TRS resource / opportunity, and the TRS availability indication may not be notified to the terminal 10 when the TRS is not actually transmitted. Conversely, the TRS availability indication may be notified to the terminal 10 only when the TRS is not actually transmitted.

[0057] For such signaling of the TRS availability indication, physical layer (L1) based signaling (hereinafter referred to as "L1 signaling") or RRC layer signaling (hereinafter referred to as "RRC signaling") may be used.

[0058] When using L1 signaling, the TRS availability indication may be the value of a predetermined field of the DCI, or may be a specific signal (e.g., SSB or TRS, etc.) or a specific sequence of the specific signal. The DCI including the TRS availability indication may be the DCI used for scheduling the PDSCH that transmits the paging message (also referred to as "paging DCI"), or may be the DCI including the field used for Paging early indication (PEI) (also referred to as "PEI DCI"). For example, the paging DCI and / or the PEI DCI may be CRC scrambled by a specific RNTI (e.g., P-RNTI) set using upper layer signaling such as an RRC message.

[0059] The PEI is indication information regarding the paging target in the PO. The terminal 10 determines whether the terminal 10 or the group (or subgroup) to which the terminal 10 belongs is the paging target in the PO based on the PEI (or based on whether the PEI is detected). The terminal 10 can reduce power consumption by skipping PDCCH monitoring and / or receiving and / or decoding the paging message for a PO that is not the paging target. Note that the PEI is not limited to the value of a predetermined field of the DCI, and may be a specific signal (e.g., SSB or TRS) or a specific sequence of the specific signal. The specific signal may be used as the TRS availability indication.

[0060] When using RRC signaling, the TRS availability indication may be the value of a parameter or IE included in system information (e.g., SIB1 or SIBx other than SIB1, etc.) or an RRC message (e.g., an RRC release message used for releasing the RRC connection, etc.).

[0061] The period during which the above TRS availability indication is considered valid (hereinafter referred to as the "validity time") may be defined in advance in the specification. Alternatively, information regarding the validity period (hereinafter referred to as "validity period information") may be signaled from the base station 20 to the terminal 10. The validity period information may be included, for example, in system information, an RRC message, or DCI (e.g., the paging DCI or PEI DCI described above). The validity period may be indicated by the number of predetermined time units (e.g., radio frames, slots, subframes, or symbols, etc.), by time (e.g., milliseconds, etc.), or by the number of paging cycles, POs, or DRX cycles. If the terminal receives a TRS availability indication within the validity period, the terminal does not need to reacquire another TRS availability indication within the validity period.

[0062] The validity period may be controlled using a timer (hereinafter referred to as the "validity timer"). The validity timer may be started, for example, based on the detection of a TRS availability indication, based on the detection of system information, paging DCI, or PEI DCI, or based on an SSB, SS burst, or PO. The validity timer may expire when a period predetermined in the specification or a period indicated by the validity period information has elapsed. If the terminal 10 does not receive a TRS availability indication before the validity timer expires, the terminal 10 may assume that the TRS is not available in the corresponding TRS resource / opportunity.

[0063] Figs. 3(A) and (B) are diagrams showing an example of the TRS availability indication and the validity period according to this embodiment. For example, in Figs. 3(A) and (B), from the end timing T0 of the previous PO to the start timing T1 of the reception of the SS burst, it is in the deep sleep state, and from the end timing T3 of the SS burst to the start timing T4 of the next PO, it is in the micro sleep state except for the TRS availability indication and the reception period of the TRS. The same applies to the timings T5 to T9 as to the timings T0 to T4. Note that Figs. 3(A) and (B) are merely illustrative, and the periods during which the terminal 10 is in the deep sleep state and / or the micro sleep state can be changed as appropriate.

[0064] For example, in Fig. 3(A), the TRS availability indication is included in the PEI DCI. The terminal 10 detects the PEI DCI by monitoring in the PDCCH monitoring opportunity set for the PEI. The terminal 10 determines whether the TRS is to be transmitted before the subsequent PO based on the TRS availability indication in the PEI DCI. For example, the terminal 10 determines that the TRS is to be transmitted in the TRS resource / opportunity before the next PO based on the PEI DCI detected at the timing T2. On the other hand, the terminal 10 determines that the TRS is not to be transmitted in the TRS resource / opportunity before the next PO based on the PEI DCI detected at the timing T8.

[0065] As shown in Fig. 3(A), the validity period of the TRS availability indication indicating that the TRS is available may be from the detection timing of the PEI DCI including the TRS availability indication to the start timing of the next PO. Note that in Fig. 3(A), a timer is started at the detection timing T2 of the PEI DCI, and the timer may stop or expire at the start timing T4 of the next PO.

[0066] On the other hand, in FIG. 3(B), it is different from FIG. 3(A) in that the TRS availability indication is included in the paging DCI. In FIG. 3(B), the terminal 10 may operate by reading the PEI DCI in FIG. 3(A) as the paging DCI. As shown in FIG. 3(B), the validity period of the TRS availability indication may be from the end timing of the PO that detected the paging DCI including the TRS availability indication to the start timing of the next PO. According to the TRS availability indication using the paging DCI, even when the PEI is not transmitted, it is possible to flexibly change whether to transmit the TRS in the set TRS resource.

[0067] FIGS. 4(A) and (B) are diagrams showing other examples of the TRS availability indication and the validity period according to the present embodiment. FIGS. 4(A) and (B) are different from FIGS. 3(A) and 3(B) in that the validity period of the TRS availability indication extends over one or more POs.

[0068] In FIG. 4(A), the differences between the TRS availability indication included in the paging DCI and FIG. 3(B) will be mainly described. Note that the validity period extending over one or more POs is also applicable to the TRS availability indication using the PEI described in FIG. 3(A). For example, in FIG. 4(A), the validity period of the TRS availability indication may be 4 paging cycles. For example, as shown in FIG. 4(A), when a paging DCI including the TRS availability indication is detected in a certain PO, the TRS availability indication may indicate whether the TRS is transmitted in the TRS resource set during 4 paging cycles from the PO.

[0069] In FIG. 4(B), an example of the TRS availability indication in the system information (for example, SIB1 or SIBx) is shown. The terminal 10 may determine whether to transmit the TRS in the TRS resource set before each PO based on the availability indication in the system information. According to the TRS availability indication using the system information, it is suitable for cases where the validity period is relatively long.

[0070] In addition, in FIGS. 3 and 4, the PDCCH monitoring opportunity for DCI used for the TRS availability indication may be determined based on at least one time position of the SS burst, the SS burst set, and the PO. For example, the PDCCH monitoring opportunity may be determined based on the time position and a time offset with respect to the time position. The time offset may be based on the subcarrier spacing of the SSB or the bandwidth part (BWP).

[0071] (TRS-related operations) As described above, when it is possible to control whether to actually transmit the TRS in the TRS resource / period by notifying the terminal 10 of the TRS availability indication and / or providing a validity period for the TRS availability indication, it is desirable to appropriately control the operations related to the TRS (hereinafter referred to as "TRS-related operations"). Hereinafter, the TRS-related operations in the following cases will be described: (1) when the terminal 10 performs reselection of the cell on which it camps (hereinafter referred to as "cell reselection"), (2) when the active timer is running, and (3) when the system information is used to indicate the availability of the TRS.

[0072] Note that, hereinafter, as an example of the system information, SIBx other than SIB1 (where x is an identifier of the SIB type such as 2, 3, 4, etc.) will be described, but the system information in this embodiment is not limited to SIBx. Also, hereinafter, it is assumed that the terminal 10 is in the idle state or the inactive state, but it does not prevent the application in the connected state.

[0073] (1) TRS-related operations during cell reselection The TRS-related operations of the terminal 10 during cell reselection will be described. The terminal 10 receives SIBx when performing cell selection or cell reselection. The SIBx is assumed to be either area-specific or cell-specific. When the terminal 10 performs cell reselection among cells within the same area, it does not need to receive the area-specific SIBx again. The SIBx used for configuring the TRS resource / opportunity is also assumed to be either area-specific or cell-specific.

[0074] Therefore, when the terminal 10 performs reselection of the cell it camps on, it controls a valid timer regarding the validity period of the TRS availability indication indicating that the TRS is available in the TRS resource / opportunity based on whether the SIBx used for configuring the TRS resource / opportunity is area-specific.

[0075] FIG. 5 is a diagram showing an example of the TRS-related operations during cell reselection according to the present embodiment. For example, in FIG. 5, it is assumed that cells #0 and #1 are included in area #1, and cells #2 and #3 are included in area #2. In FIG. 5, the terminal 10 camps on cell #0 and receives the area #1-specific SIBx from the base station 20 forming cell #0. The terminal 10 may configure the TRS resource / opportunity based on the TRS resource / opportunity information included in the SIBx.

[0076] Also, the terminal 10 camping on cell #0 receives the TRS availability indication. The TRS availability indication may be included in any one of the above area #1-specific SIBx, paging DCI, PEI DCI, TRS as PEI, or RRC message. The terminal 10 starts the valid timer of the TRS availability indication at timing T1.

[0077] For example, in FIG. 5, at timing T2, the terminal 10 reselects cell #1 belonging to area #1 which is the same as cell #0. Since the SIBx received in cell #0 is specific to area #1 and the reselected cell #1 belongs to the same area #1 as cell #0, the terminal 10 continues the running of the relevant TRS operation without stopping the valid timer at timing T2. Also, since the terminal 10 has received the SIBx specific to area #1 in cell #0, when reselecting cell #1, it does not need to receive the SIBx again.

[0078] Also, in FIG. 5, at timing T3, the terminal 10 reselects cell #2 belonging to area #2 which is different from cell #1. Since the reselected cell #2 belongs to area #2 which is different from area #1 to which cell #1 belongs, the terminal 10 stops the valid timer at timing T3 without waiting for the expiration at timing T4. Note that the stop of the valid timer may be alternatively expressed as reset or discard, etc.

[0079] When reselecting cell #2, since the area IDs to which cells #1 and #2 belong are different, the terminal 10 receives SIBx from the base station 20 forming cell #2. In FIG. 5, it is assumed that the SIBx is specific to area #2, but this is not limiting. The terminal 10 may set the TRS resource / opportunity based on the TRS resource / opportunity information included in the SIBx. The terminal 10 camping on cell #2 may receive a TRS availability indication and start the valid timer for the TRS availability indication at timing T3. The valid timer expires at timing T5, and the valid period of the TRS availability indication received in cell #2 ends.

[0080] As described above, when the SIBx including the TRS resource / opportunity information is area-specific, if the terminal 10 performs cell reselection between cell #0 and cell #1 belonging to the same area #1, it continues without resetting the valid timer. On the other hand, if the terminal 10 performs cell reselection between cell #1 and cell #2 belonging to different areas #1 and #2, respectively, it resets the valid timer. Therefore, even when the terminal 10 moves between cells belonging to the same area or between cells belonging to different areas, the valid period of the TRS availability indication can be appropriately controlled.

[0081] FIG. 6 is a diagram showing another example of TRS-related operations during cell reselection according to the present embodiment. For example, in cells #4 and #5 in FIG. 6, it is assumed that cell-specific SIBx is notified respectively. In FIG. 6, the terminal 10 camps on cell #4 and receives the cell #4-specific SIBx from the base station 20 forming cell #4. The terminal 10 may set the TRS resource / opportunity based on the TRS resource / opportunity information included in the SIBx.

[0082] Also, the terminal 10 camping on cell #4 receives a TRS availability indication. The TRS availability indication may be included in any of the above cell #4-specific SIBx, paging DCI, PEI DCI, TRS as PEI, or RRC message. The terminal 10 starts the valid timer of the TRS availability indication at timing T1. For example, in FIG. 6, the valid period is from timing T1 to T3.

[0083] In FIG. 6, the terminal 10 reselects cell #5 which is different from cell #4 at timing T2. The terminal 10 stops the valid timer at timing T2 without waiting for the expiration at timing T3. Also, the terminal 10 receives SIBx specific to cell #5 and sets the TRS resource / opportunity based on the TRS resource / opportunity information in the SIBx. The terminal 10 camping on cell #5 may receive the TRS availability indication and start the valid timer for the TRS availability indication at timing T2. The valid timer expires at timing T4, and the valid period of the TRS availability indication received in cell #5 ends.

[0084] As described above, the terminal 10 controls the valid timer of the TRS availability indication based on whether the SIBx including the TRS resource / opportunity information is area-specific. Therefore, even when the terminal 10 moves between cells, the valid period of the TRS availability indication can be appropriately controlled.

[0085] (2) TRS-related operations during the activation of the valid timer Next, the operation of the terminal 10 when the transmission of the TRS is stopped during the activation of the valid timer will be described. The terminal 10 may control the valid period of the TRS availability indication using the valid timer. For example, the terminal 10 may determine that the TRS availability indication is valid during the period from when the valid timer is started until it expires or is stopped (i.e., while the valid timer is activated). Even during the activation of such a valid timer, an operation of stopping the transmission of the TRS is also assumed for reasons such as the disappearance of the terminal in the connected state in the cell.

[0086] Figs. 7(A) and (B) are diagrams showing an example of the TRS operation during the activation of the valid timer according to this embodiment. In Figs. 7(A) and (B), it is assumed that the TRS availability indication is included in the paging DCI, but it is not limited thereto, and it may be signaled to the terminal 10 using higher layer signaling such as system information or RRC messages, or physical layer signaling such as PEI DCI or a specific signal for PEI. Of course, the start timing of the valid timer is not limited to that shown in the figures.

[0087] In Fig. 7(A), an example is shown in which the valid timer started at timing T1 expires at timing T2. As shown in Fig. 7(A), the terminal 10 detects a paging DCI including a TRS availability indication (first indication information) indicating that the TRS is available in the PDCCH monitoring opportunity within PO#0. The terminal 10 may start a valid timer in response to the detection of the TRS availability indication, and determine the period until the valid timer expires as the valid period of the TRS availability indication. The terminal 10 determines that the TRS is available in the TRS resource / opportunity within the valid period based on the TRS availability indication.

[0088] Also, the terminal 10 detects a paging DCI indicating that the TRS is not available in the PDCCH monitoring opportunity within PO#4 after the expiration of the valid timer. The terminal 10 determines that the TRS is not available in the TRS resource / opportunity based on the paging DCI.

[0089] In Fig. 7(B), an example is shown in which the valid timer started at timing T1 stops at timing T1'. As shown in Fig. 7(B), the terminal 10 is different from Fig. 7(A) in that it receives a TRS availability indication (second indication information) indicating that the TRS is not available at timing T1' during the activation of the valid timer. Fig. 7(B) will be described centering on the differences from Fig. 7(A).

[0090] The terminal 10 detects paging DCI including a TRS availability indication indicating that the TRS is not available in the PDCCH monitoring opportunity within PO#2 during the activation of the valid timer. The terminal 10 stops the valid timer in response to the detection of the TRS availability indication. The terminal 10 determines that the TRS is not available in the TRS resource / opportunity after stopping the timer. Thus, when the terminal 10 stops the valid timer at timing T1’, it may determine that the validity period of the TRS availability indication detected in PO#0 has ended without waiting for the expiration of the valid timer.

[0091] Note that the TRS availability indication indicating that the TRS is not available, which is notified during the activation of the valid timer, may be a specific value of at least some bits in the reserved field of the paging DCI (for example, the value “00” of 2 bits out of 6 bits).

[0092] As described above, when the terminal 10 receives a TRS availability indication indicating that the TRS is not available during the activation of the valid timer regarding the validity period of the TRS availability indication indicating that the TRS is available, the terminal 10 may stop the valid timer and assume that the TRS is not available in subsequent TRS resources / opportunities. Thereby, even when the system side changes whether to transmit the TRS by operation, the terminal 10 can operate appropriately.

[0093] (3) TRS-related operations based on SIBx Next, the operation of the terminal 10 when indicating the availability of the TRS using SIBx will be described. Specifically, (3.1) the operation of changing the indication regarding the availability of the TRS using SIBx and (3.2) the operation of controlling the validity period of the indication regarding the availability of the TRS using SIBx will be described.

[0094] (3.1) Operation of changing the TRS availability indication using SIBx As described with reference to FIG. 2, generally, when the content of SIBx is changed, the terminal 10 detects notification information regarding the change of the SIBx (hereinafter referred to as "SI change notification") during a certain update period, and obtains an SI message including the changed SIBx during the next update period. The SI change notification is also called "SI change indication" or the like. For example, a short message in the paging DCI may be used as the SI change notification. The paging DCI may be monitored at each PO within the certain update period.

[0095] Based on the SI change notification detected during the previous update period, the terminal 10 may receive an SI message including the SIBx updated during the next update period. The update period may be composed of, for example, a predetermined number of radio frames. The boundary of the update period may be determined based on, for example, the SFN and the number of radio frames constituting the update period.

[0096] By the way, it is desired that whether the TRS is actually transmitted in the TRS resource / opportunity can be changed by various factors. For example, when the traffic of the entire system increases, it is assumed that the overhead due to the TRS is reduced by not actually transmitting the TRS in the set TRS resource / opportunity. On the other hand, when the traffic of the entire system decreases, it is assumed that the effect of reducing the power consumption of the terminal 10 is enhanced by actually transmitting the TRS in the set TRS resource / opportunity.

[0097] Thus, when whether the TRS is actually transmitted in the TRS resource / opportunity is changed, the problem is how to notify the terminal 10 of the change. Here, when the terminal 10 determines whether the TRS is actually transmitted in the TRS resource / opportunity based on the TRS availability indication in the SIBx, it is assumed that the update procedure of the SI message (hereinafter referred to as "SI update procedure") is used.

[0098] However, in the SI update procedure, it is not assumed that the value of the TRS availability indication in SIBx (or whether SIBx includes the TRS availability indication) will be changed. Therefore, simply using the SI update procedure may not be able to appropriately control the timing at which the above TRS availability indication becomes valid and / or the validity period of the TRS availability indication.

[0099] Therefore, when the TRS availability indication in SIBx changed by the SI update procedure indicates that TRS is actually transmitted in the TRS resource / opportunity, the terminal 10 may determine the timing at which the TRS availability indication becomes valid (i.e., the start timing of the validity timer) based on a reference timing (hereinafter referred to as "reference timing").

[0100] The reference timing may be, for example, the timing related to the reception of SIBx including the TRS availability indication indicating that TRS is available, the timing related to the reception of SIBx other than the SIBx or SIB1, or the boundary of the update period. The timing related to reception may be the start or end timing of the received radio frame, slot, or symbol, or the start or end timing of the period used for reception (e.g., SI window), etc.

[0101] In addition, the terminal 10 may determine the start timing of the validity timer based on the above reference timing and an offset with respect to the reference timing. The offset may be defined by the number of slots, the number of radio frames, the number of hyper radio frames, time (e.g., milliseconds), an integer multiple of the paging cycle, or an integer multiple of the DRX cycle, etc. The offset may be defined in advance in the specification or notified from the base station 20. Also, the value of the offset may be 0, and the terminal 10 may determine the above reference timing as the timing at which the TRS availability indication becomes valid.

[0102] Further, the terminal 10 may receive information regarding the offset (hereinafter referred to as "offset information") from the base station 20. The offset information may be included in SIBx including the TRS availability indication, may be included in other SIBx, may be included in SIB1, or may be included in other RRC messages.

[0103] FIG. 8 is a diagram showing an example of the SI update procedure according to this embodiment. For example, in FIG. 8, the TRS availability indication in SIBx indicates that the TRS is actually transmitted in the TRS resource / opportunity. When the TRS is not actually transmitted, SIBx does not include the TRS availability indication. However, as described above, it is needless to say that the TRS availability indication indicating whether the TRS is actually transmitted in the TRS resource / opportunity may be included in SIBx.

[0104] For example, in FIG. 8, SIBx transmitted within the previous update period does not include the TRS availability indication, indicating that the TRS is not actually transmitted in the TRS resource / opportunity. On the other hand, when a factor for which the TRS should actually be transmitted is detected within the previous update period, the base station 20 transmits an SI change notification of the SI message including SIBx in the PO. When the terminal 10 detects the SI change notification by monitoring the PDCCH in the PO, it receives SIB1 in the next update period and receives an SI message including the changed SIBx based on the SIB1. Although not shown, the terminal 10 may receive the MIB before SIB1 after the boundary.

[0105] Also, the version information of SIBx in SIB1 of FIG. 8 (e.g., RRC IE "valueTag") indicates v1 which is obtained by adding 1 to v0. Since the version information of SIBx in SIB1 (here v1) does not match the version information of SIBx stored in the terminal 10 (here v0), the terminal 10 may acquire the SI message including SIBx of v1. The terminal 10 determines that the TRS is actually transmitted in the TRS resource / opportunity based on the TRS availability indication in SIBx of v1.

[0106] Also, in FIG. 8, the terminal 10 may use the boundary of the update period as the reference timing, and determine the timing at which the TRS availability indication becomes valid based on the reference timing and the offset. The terminal 10 may start the validity timer at the determined timing. The terminal 10 may determine the period from when the validity timer is started until it expires as the valid period of the TRS availability indication. The valid period may be defined as an integer multiple of the update period.

[0107] As shown in FIG. 8, when the validity timer expires, the base station 20 stops transmitting the TRS in the TRS resource / opportunity. Also, the base station 20 may stop notifying SIBx of v1. The base station 20 may stop transmitting the TRS after the validity timer expires and may not transmit the SI change notification. That is, after the validity timer expires, the base station 20 does not need to notify SIBx of v2 indicating that the TRS is not transmitted. Also, the version information of SIBx in SIB1 does not need to be updated, and v1 may be maintained.

[0108] Note that in FIG. 8, the boundary of the update period is used as the reference timing. However, as described above, the reference timing may be the timing related to the reception of the SI message including SIBx of v1 including the TRS availability indication, the timing related to the SI window in which the SI message is transmitted, or the timing related to the reception of SIB1, etc.

[0109] As described above, even when the TRS availability indication in SIBx changed by the SI update procedure indicates that the TRS is actually transmitted in the TRS resource / opportunity, the start timing of the valid timer and / or the validity period of the TRS availability indication can be appropriately controlled.

[0110] (3.2) Control operation of the validity period using SIBx By the way, while the terminal 10 camping on a certain cell starts the above valid timer based on SIBx, it is assumed that another terminal 10 starts camping on the certain cell. In this case, when the valid timer expires, the base station 20 does not actually transmit the TRS in the TRS resource / opportunity. Therefore, among the terminals 10 belonging to the same cell, the expiration timing of the valid timer (that is, the end timing of the validity period of the TRS availability indication in SIBx) needs to be the same.

[0111] Therefore, when the base station 20 notifies information regarding the validity period of the TRS availability indication (hereinafter, "validity period information"), the base station 20 generates the validity period information based on the elapsed time since the start of the running valid timer. The valid time information may be included in SIBx including the TRS availability indication, or may be included in another SIB (for example, another SIBx or SIB1, etc.). For example, the valid time information may indicate how long the TRS availability indication is valid. Note that the elapsed time since the start of the running valid timer may be paraphrased as the remaining time until the valid timer expires.

[0112] When the validity period information indicates, for example, the remaining time until the expiration timing of the valid timer, the remaining time may be updated based on the elapsed time from the start timing of the validity period. Alternatively, the validity period information may indicate, for example, the time of the expiration timing of the valid timer, the number of radio frames, or the number of hyper radio frames. That is, the validity period information may absolutely indicate the expiration timing of the valid timer. For example, the validity period information may be defined using UTC (Universal Time Coordinated) time and indicate when the TRS availability indication (for example, the content of the TRS availability indication) expires.

[0113] FIG. 9 is a diagram showing an example of the control operation of the validity period of the TRS availability indication according to the present embodiment. For example, in FIG. 9, it is assumed that the terminal 10A is camped on a certain cell and the valid timer indicating the validity period of the TRS availability indication in SIBx is running. Note that in FIG. 9, the start timing of the activation of the valid timer is equal to the end timing of the reception of SIBx, but this is merely an example and is not limited thereto. As described above, the start timing may be determined based on the reference timing and the offset.

[0114] For example, in FIG. 9, the validity period information in SIBx indicates the remaining time until the valid timer expires. As shown in FIG. 9, when SIBx is notified at a predetermined period, the remaining time indicated by the validity period information included in each SIBx may be determined based on the elapsed time since the start of the valid timer from the initial value. For example, the validity period information in SIBx received while the valid timer is not activated indicates 10 seconds of the initial value. On the other hand, the validity period information in SIBx received during the activation of the valid timer may indicate a remaining time of 3 seconds based on the elapsed time from 10 seconds of the initial value.

[0115] As described above, the value indicated by the validity period information in SIBx may be updated based on the elapsed time from the start timing of the validity timer. Thereby, even when terminal 10B camps on the same cell as terminal 10A while the validity timer in terminal 10A is running, it is possible to avoid a mismatch in the expiration timing of the validity timer between terminals 10A and 10B.

[0116] Note that, as shown in FIG. 9, the remaining time indicated by the validity period information in SIBx may be updated every period of SIBx. Even when the validity period information in SIBx is updated, base station 20 may not transmit the above SI change notification. On the other hand, when extending the initial value (10 seconds in FIG. 9) indicated by the validity period information in SIBx, base station 20 may perform an SI update procedure based on the above SI change notification and notify v2 SIBx including the validity period information indicating the extended initial value.

[0117] FIG. 10 is a diagram showing another example of the control operation of the validity period of the TRS availability indication according to the present embodiment. For example, in FIG. 10, the validity period information indicates SFN#128 as the expiration timing of the validity period. Note that other operations in FIG. 10 are the same as those described in FIG. 9.

[0118] As described above, since the validity period information in SIBx indicates the time when the validity period expires or the index of the time unit, it is not necessary to sequentially update based on the elapsed time from the start timing of the validity timer. Therefore, even without performing the update operation of the validity period information in base station 20 described in FIG. 9, it is possible to avoid a mismatch in the expiration timing of the validity timer between terminals 10.

[0119] (Configuration of Radio Communication System) Next, the configuration of each device of the radio communication system 1 as described above will be described. Note that the following configuration is for showing the necessary configuration in the description of the present embodiment, and does not exclude the possibility that each device includes functional blocks other than those shown in the drawings.

[0120] <Hardware Configuration> FIG. 11 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to this embodiment. Each device (for example, terminal 10, base station 20, CN 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, an input device that accepts various input operations, and an input / output device 14 that outputs various information.

[0121] 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 a program from the storage device 12 and executing it. Each device in the wireless communication system 1 may be configured by one or more processors 11. Also, each of these devices may be called a computer.

[0122] The storage device 12 is composed of, for example, a memory, an HDD (Hard Disk Drive), and / or an SSD (Solid State Drive) and the like. The storage device 12 may store various information (for example, a program executed by the processor 11, etc.) necessary for the execution of the processing by the processor 11.

[0123] 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. Also, the communication device 13 may include an amplifier, an RF (Radio Frequency) device that processes radio signals, and a BB (BaseBand) device that performs baseband signal processing.

[0124] The RF device generates a radio signal to be transmitted from antenna A by performing, for example, D / A conversion, modulation, frequency conversion, power amplification, etc. on the digital baseband signal received from the BB device. Further, the RF device generates a digital baseband signal by performing frequency conversion, demodulation, A / D conversion, etc. on the radio signal received from the antenna and transmits it to the BB device. The BB device performs a process of converting a digital baseband signal into a packet and a process of converting a packet into a digital baseband signal.

[0125] The input / output device 14 includes, for example, an input device such as a keyboard, a touch panel, a mouse, and / or a microphone, and an output device such as a display and / or a speaker.

[0126] The hardware configuration described above is merely an example. Each device in the wireless communication system 1 may have some of the hardware described in FIG. 11 omitted, or may be provided with hardware not described in FIG. 11. Also, the hardware shown in FIG. 11 may be constituted by one or a plurality of chips.

[0127] <Functional block configuration> ≪Terminal≫ FIG. 12 is a diagram showing an example of the functional block configuration of the terminal according to the present embodiment. As shown in FIG. 12, the terminal 10 includes a receiving unit 101, a transmitting unit 102, and a control unit 103.

[0128] Note that 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. Also, 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. Further, the program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-transitory storage medium (Non-transitory computer readable medium). The non-transitory storage medium is not particularly limited, and for example, it may be a storage medium such as a USB memory or a CD-ROM.

[0129] The receiving unit 101 receives a downlink signal. Also, the receiving unit 101 may receive information and / or data transmitted via the downlink signal. Here, "receiving" may include performing processes related to reception such as, for example, reception of a radio signal, demapping, demodulation, decoding, monitoring, and measurement. The downlink signal may include at least one of, for example, PDSCH, PDCCH, downlink reference signal, synchronization signal, PBCH, etc.

[0130] The receiving unit 101 monitors PDCCH candidates within a search space to detect DCI. The receiving unit 101 may receive downlink user data and / or higher layer control information (for example, Medium Access Control Element (MAC CE), RRC message, or NAS message, etc.) via the PDSCH scheduled using the DCI.

[0131] Specifically, the receiving unit 101 receives SIBx (system information). Also, the receiving unit 101 may receive indication information indicating that the TRS is available during the TRS resource / period (resource and / or period) (see, for example, (1) and (2) above). The indication information may be included in SIBx, paging DCI, or PEI DCI.

[0132] Further, while the valid timer is running, the receiving unit 101 may receive indication information (second indication information) indicating that the TRS is available in the TRS resource / opportunity (see, for example, (2) above). The indication information may be included in the paging DCI, or may be a specific value of at least some bits in the reserved field of the paging DCI.

[0133] Further, the receiving unit 101 may receive an SIBx including indication information indicating that the TRS is available in the TRS resource / opportunity (see, for example, (3) above). The receiving unit 101 may receive the SIBx in the next update period based on the SI change notification (system information change notification) detected in the previous update period (see, for example, FIG. 8). Further, the receiving unit 101 may receive offset information with respect to the reference timing.

[0134] Further, the receiving unit 101 may receive validity period information regarding the validity period of the indication information indicating that the TRS is available in the TRS resource / opportunity. The validity period information indicates the remaining time until the expiration timing of the valid timer, and the remaining time may be updated based on the elapsed time from the start timing of the validity period (see, for example, FIG. 9). Alternatively, the validity period information may indicate the expiration timing, the radio frame number, or the hyper radio frame number (see, for example, FIG. 10).

[0135] The transmitting unit 102 transmits an uplink signal. Further, the transmitting unit 102 may transmit information and / or data transmitted via the uplink signal. Here, "transmit" may include performing processes related to transmission such as, for example, encoding, modulation, mapping, and transmission of a radio signal. The uplink signal may include, for example, at least one of an uplink shared channel (e.g., Physical Uplink Shared Channel (PUSCH)), a random access preamble (e.g., Physical Random Access Channel (PRACH)), and an uplink reference signal.

[0136] The transmitting unit 102 may transmit uplink user data and / or higher layer control information (e.g., MAC CE, RRC message, etc.) via a PUSCH scheduled using the DCI received by the receiving unit 101.

[0137] The control unit 103 performs various controls in the terminal 10.

[0138] For example, the control unit 103 may set TRS resources / opportunities based on SIBx or an RRC message.

[0139] Also, when the control unit 103 performs reselection of the cell to camp on, it may control a valid timer regarding the validity period of the TRS availability indication based on whether SIBx is area-specific (see, for example, (1) above, FIGS. 5 and 6). Specifically, when SIBx is area-specific, if the control unit 103 performs cell reselection between cells belonging to the same area during the activation of the valid timer, the valid timer may continue. Also, when SIBx is area-specific, if the control unit 103 performs cell reselection between cells belonging to different areas during the activation of the valid timer, the valid timer may be stopped. Also, when SIBx is not area-specific, if the control unit 103 performs cell reselection between cells during the activation of the valid timer, the valid timer may be stopped.

[0140] Also, the control unit 103 controls a valid timer regarding the validity period of the TRS availability indication. Specifically, the control unit 103 starts a timer regarding the validity period of first indication information indicating that the TRS is available in the TRS resources / opportunities (see, for example, (2) above, FIG. 7(A)). Also, when the second indication information indicating that the TRS is not available in the TRS resources / opportunities is received by the receiving unit 101 while the valid timer is activated, the control unit 103 may stop the valid timer (see, for example, (2) above, FIG. 7(B)).

[0141] Specifically, when the control unit 103 detects DCI (for example, paging DCI) scrambled by a specific RNTI in a PDCCH monitoring opportunity in PO, it may stop the valid timer based on the second instruction information in the DCI (for example, refer to FIG. 7(B)). Further, the control unit 103 may determine that the TRS is not transmitted in a TRS resource / opportunity after a predetermined timing after the stop of the valid timer (for example, refer to FIG. 7(B)).

[0142] Further, the control unit 103 may determine the start timing of the valid timer using the timing related to the reception of SIBx, the timing related to the reception of system information other than the above system information, or the boundary of the update period as the reference timing (for example, refer to the above (3) and FIG. 8). The control unit 103 may determine the start timing of the valid timer based on the reference timing and the offset indicated by the offset information. Further, the control unit 103 may determine the expiration timing of the valid timer based on the above valid period information.

[0143] ≪Base Station≫ FIG. 13 is a diagram showing an example of the functional block configuration of the base station according to the present embodiment. As shown in FIG. 13, the base station 20 includes a receiving unit 201, a transmitting unit 202, and a control unit 203.

[0144] Note that 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. Further, all or part of the functions realized by the receiving unit 201 and the transmitting unit 202 and the control unit 203 can be realized by the processor 11 executing a program stored in the storage device 12. Further, 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.

[0145] The receiving unit 201 receives the uplink signal described above. Further, the receiving unit 201 may receive information and / or data transmitted via the uplink signal.

[0146] The transmitting unit 202 transmits the downlink signal described above. Further, the transmitting unit 202 may transmit information and / or data transmitted via the downlink signal. Specifically, the transmitting unit 202 transmits SIBx (system information). Further, the transmitting unit 202 may transmit indication information indicating that TRS is available in the TRS resource / period (resource and / or period).

[0147] Further, the transmitting unit 202 may transmit indication information (second indication information) indicating that TRS is available in the TRS resource / opportunity while the valid timer is activated (see, for example, (2) above).

[0148] Further, the transmitting unit 202 may transmit SIBx including indication information indicating that TRS is available in the TRS resource / opportunity (see, for example, (3) above). The transmitting unit 202 may transmit the SIBx in the next update period based on the SI change notification (system information change notification) detected in the previous update period (see, for example, FIG. 8). Further, the transmitting unit 202 may transmit offset information with respect to the reference timing. Further, the transmitting unit 202 may transmit validity period information regarding the validity period.

[0149] The control unit 203 performs various controls in the base station 20. For example, the control unit 203 may control whether to transmit TRS in the TRS resource / opportunity based on various factors. Note that a part of the information transmitted from the transmitting unit 202 of the base station may be transmitted by the transmitting unit in the device on the core network 30.

[0150] (Supplementary note) The various signals, information, and parameters in the above embodiments may be signaled at any layer. That is, the above various signals, information, and parameters may be replaced with signals, information, and parameters of any layer, such as a higher layer (e.g., Non-Access Stratum (NAS) layer, RRC layer, MAC layer, etc.) or a lower layer (e.g., physical layer). Also, the notification of predetermined information is not limited to being explicitly performed and may be implicitly performed (e.g., by not notifying information or by using other information).

[0151] Also, the names of the various signals, information, parameters, IEs, channels, time units, and frequency units in the above embodiments are merely illustrative and may be replaced with other names. For example, a slot may have any name as long as it is a time unit having a predetermined number of symbols. Also, an RB may have any name as long as it is a frequency unit having a predetermined number of subcarriers. Also, "first ~" and "second ~" are merely for identifying a plurality of information or signals, and the order may be appropriately changed.

[0152] Also, the uses of the terminal 10 in the above embodiments (e.g., for RedCap, IoT, etc.) are not limited to the examples and may be used for any use (e.g., eMBB, URLLC, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.) as long as it has the same function. Also, the formats of various information are not limited to the above embodiments and may be appropriately changed, such as bit representation (0 or 1), true / false value (Boolean: true or false), integer value, character, etc. Also, the singular and plural in the above embodiments may be changed to each other.

[0153] The embodiments described above are for facilitating the understanding of the present disclosure and are not for limiting the interpretation of the present disclosure. The flowcharts, sequences, each element included in the embodiments, and their arrangements, indexes, conditions, etc. described in the embodiments are not limited to those illustrated and can be changed as appropriate. Also, at least a part of the configurations described in the above embodiments can be partially replaced or combined.

Description of Reference Numerals

[0154] 1... Wireless communication system, 20... Base station, 30... Core network, 101... Receiver, 102... Transmitter, 103... Control unit, 201... Receiver, 202... Transmitter, 203... Control unit, 11... Processor, 12... Storage device, 13... Communication device, 14... Input / output device

Claims

1. A receiving unit that receives system information including information regarding the power of a tracking reference signal (TRS) in each setting, a setting indicating resources for a plurality of TRSs including a synchronization signal block (SSB) index, an index indicating the correspondence between the setting indicating the resources for the plurality of TRSs and the TRS availability indication for each setting indicating the resources for each TRS, and information indicating the validity period of the TRS availability indication, and receives downlink control information including the TRS availability indication on a physical downlink control channel; A control unit that determines the availability of the TRS in the resources for the TRS corresponding to the TRS availability indication during a period based on the information indicating the validity period of the TRS availability indication when the TRS availability indication included in the downlink control information is received; A terminal comprising:

2. The period is based on a radio frame identified by a system frame number. The terminal according to claim 1.

3. A transmitting unit that transmits system information including information regarding the power of a tracking reference signal (TRS) in each setting, a setting indicating resources for a plurality of TRSs including a synchronization signal block (SSB) index, an index indicating the correspondence between the setting indicating the resources for the plurality of TRSs and the TRS availability indication for each setting indicating the resources for each TRS, and information indicating the validity period of the TRS availability indication, and transmits downlink control information including the TRS availability indication on a physical downlink control channel; A control unit that controls to transmit the TRS in the resources for the TRS corresponding to the TRS availability indication during a period based on the information indicating the validity period of the TRS availability indication when the TRS availability indication included in the downlink control information is transmitted; A base station comprising:

4. The period is based on a radio frame identified by a system frame number, The base station according to claim 3.

5. Receiving system information including information regarding the power of a tracking reference signal (TRS) and a setting indicating resources for a plurality of TRSs each including a synchronization signal block (SSB) index for each setting, an index indicating the correspondence between the setting indicating the resources for the plurality of TRSs and a TRS availability indication for each setting indicating the resources for each TRS, and information indicating the validity period of the TRS availability indication, and receiving downlink control information including the TRS availability indication on a physical downlink control channel; When receiving the TRS availability indication included in the downlink control information, determining the availability of the TRS in the resources for the TRS corresponding to the TRS availability indication during a period based on the information indicating the validity period of the TRS availability indication; A wireless communication method for a terminal comprising:

6. The period is based on a radio frame identified by a system frame number, The wireless communication method according to claim 5.

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