Communication device, base station and communication method

Abstract

To make it possible to correctly determine whether a TRS is transmitted on the basis of a TRS source set with a communication device set.MEANS FOR SOLVING THE PROBLEM: A communication device (100) includes a reception part (112) for receiving downlink control information (DCI) from a base station, and a control part (120) for determining a bit number of a bit map of an availability indicator of a tracking reference signal (TRS) included in the DCI. The control part determines a bit number of a bit map of the availability indicator on the basis of an identifier associated with a resource of the TRS included in TRS resource set setting in the case of receiving the TRS resource set setting for setting the resource of the TRS from the base station. The reception part receives the TRS in the resource of the TRS from the base station on the basis of a value of bits of the bit map of the availability indicator of the determined bit number.SELECTED DRAWING: Figure 8

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from patent application serial number 2022-001588, filed January 7, 2022, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a communication device, a base station, and a communication method used in a mobile communication system. [Background technology]

[0003] In mobile communication systems that comply with the technical specifications of 3GPP (3rd Generation Partnership Project), a standardization project for mobile communication systems, a tracking reference signal (TRS) is included in the reference signals (RS) that are individually set for communication devices in a radio resource control (RRC) connected state. The TRS is a reference signal for time-frequency synchronization (time-frequency tracking).

[0004] In 3GPP, discussions are underway to standardize a technology for reducing power consumption for communication devices in an RRC idle state or an RRC inactive state. In such a technology, it is being considered to make TRS resources (also referred to as "TRS opportunities") configured for communication devices in an RRC connected state available for communication devices in an RRC idle state or an RRC inactive state (see, for example, Non-Patent Document 1). Specifically, a base station broadcasts TRS resource configuration using a system information block (also referred to as "broadcast information").

[0005] A communication device in an RRC idle state or an RRC inactive state can receive a TRS using the TRS resource configuration configured by the system information block, thereby achieving synchronization without receiving an SSB (SS / PBCH Block), and can shorten the wake-up duration from establishing synchronization to monitoring paging. Furthermore, by not receiving an SSB, an increase in power consumption due to receiving an SSB is suppressed.

[0006] The base station transmits, to the communication device, downlink control information (DCI) including an availability indicator indicating whether the TRS is to be transmitted based on the TRS resource set configured by the TRS resource configuration. The communication device determines whether the TRS is to be transmitted based on the configured TRS resource set based on the availability indicator (see, for example, Non-Patent Document 1). Note that the availability indicator field in which the availability indicator is stored is a variable-length field indicated by a maximum of 6 bits. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP contribution: R2-2111285 Summary of the Invention

[0008] A communication device according to a first aspect includes a receiver (112) that receives downlink control information (DCI) from a base station, and a controller (120) that determines the number of bits in an availability indicator bitmap of a tracking reference signal (TRS) included in the DCI. When the controller receives a TRS resource set configuration for configuring resources for the TRS from the base station, the controller determines the number of bits in the availability indicator bitmap based on an identifier associated with the resources for the TRS included in the TRS resource set configuration. The receiver receives the TRS from the base station in the resources for the TRS based on the value of the bit of the availability indicator bitmap of the determined number of bits.

[0009] A base station according to a second aspect includes a transmitter (211) that transmits downlink control information (DCI) to a communication device (100). When the transmitter transmits a TRS resource set configuration for configuring resources of the TRS to the communication device, the transmitter transmits the TRS to the communication device in the resources of the TRS based on bit values ​​of a bitmap of an availability indicator of the TRS, the number of bits of which is based on an identifier associated with the resources of the TRS included in the TRS resource set configuration.

[0010] A communication method according to a third aspect is a communication method executed by a communication device. The communication method includes the steps of receiving downlink control information (DCI) from a base station, determining the number of bits of an availability indicator bitmap of a tracking reference signal (TRS) included in the DCI, and receiving the TRS from the base station in resources of the TRS based on the determined number of bits of the availability indicator bitmap. In the determining step, when a TRS resource set configuration for configuring resources of the TRS is received from the base station, the number of bits of the availability indicator bitmap is determined based on an identifier associated with the resources of the TRS included in the TRS resource set configuration. [Brief explanation of the drawings]

[0011] The objects, features, advantages, and other features of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a diagram showing a configuration of a mobile communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a protocol stack in the mobile communication system according to the embodiment. [Figure 3] FIG. 3 is a diagram for explaining an overview of eDRX. [Figure 4] FIG. 4 is a sequence diagram illustrating an example of operation for a UE in an RRC idle state or an RRC inactive state. [Figure 5] FIG. 5 is a sequence diagram showing an example of an operation for a UE in an RRC idle state or an RRC inactive state to receive a TRS. [Figure 6] FIG. 6 is a diagram illustrating a configuration of a UE according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating a configuration of a base station according to the embodiment. [Figure 8] FIG. 8 is a sequence diagram for explaining a first operation example according to the embodiment. [Figure 9] FIG. 9 is an explanatory diagram (part 1) for explaining a first operation example according to the embodiment. [Figure 10] FIG. 10 is an explanatory diagram (part 2) for explaining the first operation example according to the embodiment. [Figure 11] FIG. 11 is an explanatory diagram (part 3) for explaining the first operation example according to the embodiment. [Figure 12] FIG. 12 is an explanatory diagram (part 1) for explaining a second operation example according to the embodiment. [Figure 13] FIG. 13 is an explanatory diagram (part 2) for explaining the second operation example according to the embodiment. [Figure 14] FIG. 14 is an explanatory diagram for explaining a third operation example according to the embodiment. [Figure 15]FIG. 15 is a sequence diagram for explaining a fourth operation example according to the embodiment. [Figure 16] FIG. 16 is an explanatory diagram for explaining a fourth operation example according to the embodiment. [Figure 17] FIG. 17 is an explanatory diagram for explaining a fifth operation example according to the embodiment. [Figure 18] FIG. 18 is a flowchart illustrating a sixth operation example according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0013] The current 3GPP specifications do not specify a method for a communication device to determine the number of bits in the availability indicator field. As a result, there is a risk that the communication device may erroneously identify the availability indicator field and be unable to correctly determine whether a TRS is to be transmitted based on a configured TRS resource set. Therefore, an object of the present disclosure is to provide a communication device, a base station, and a communication method that can correctly determine whether a TRS is to be transmitted based on a configured TRS resource set.

[0014] (Configuration of a mobile communication system) The configuration of a mobile communication system 1 according to an embodiment will be described with reference to Fig. 1. The mobile communication system 1 is, for example, a system that complies with the 3GPP Technical Specification (TS). In the following, the mobile communication system 1 will be described using as an example a 5th Generation System (5GS) of the 3GPP standard, that is, a mobile communication system based on NR (New Radio).

[0015] The mobile communication system 1 includes a network 10 and user equipment (UE) 100 that communicates with the network 10. The network 10 includes a next generation radio access network (NG-RAN) 20 that is a 5G radio access network, and a 5G core network (5GC) 30 that is a 5G core network.

[0016] The UE 100 is an example of a communication device. The UE 100 may be a mobile wireless communication device. The UE 100 may be a device used by a user. The UE 100 may be user equipment defined in the 3GPP technical specifications. The UE 100 may be a mobile device such as a mobile phone terminal such as a smartphone, a tablet terminal, a laptop PC, a communication module, or a communication card. The UE 100 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. The UE 100 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. The UE 100 may be a sensor or a device provided therein. The UE 100 may be called by other names such as a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, or a remote unit.

[0017] The NG-RAN 20 includes multiple base stations 200. Each base station 200 manages at least one cell. A cell constitutes the smallest unit of a communication area. For example, one cell belongs to one frequency (carrier frequency) and is composed of one component carrier. The term "cell" may refer to wireless communication resources or to a communication target of the UE 100. Each base station 200 can perform wireless communication with the UE 100 located in its own cell. The base station 200 communicates with the UE 100 using a RAN protocol stack. The base station 200 provides NR user plane and control plane protocol termination for the UE 100 and is connected to the 5GC 30 via an NG interface. Such an NR base station 200 is sometimes referred to as a gNodeB (gNB).

[0018] The 5GC 30 includes a core network device 300. The core network device 300 includes, for example, an Access and Mobility Management Function (AMF) and / or a User Plane Function (UPF). The AMF performs mobility management for the UE 100. The UPF provides functions specialized for user plane processing. The AMF and the UPF are connected to the base station 200 via an NG interface.

[0019] An example of the configuration of a protocol stack in the mobile communication system 1 according to the embodiment will be described with reference to FIG.

[0020] The protocol for the wireless section between UE 100 and base station 200 includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer.

[0021] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 200 via a physical channel.

[0022] A physical channel consists of multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. One subframe consists of multiple OFDM symbols in the time domain. A resource block is a resource allocation unit and consists of multiple OFDM symbols and multiple subcarriers. A frame can be configured for 10 ms and can include 10 subframes, each of which is 1 ms long. A subframe can include the number of slots corresponding to the subcarrier spacing.

[0023] Among the physical channels, the Physical Downlink Control Channel (PDCCH) plays a central role for purposes such as downlink scheduling assignment, uplink scheduling grant, and transmit power control.

[0024] In NR, the UE 100 can use a bandwidth narrower than the system bandwidth (i.e., the cell bandwidth). The base station 200 configures the UE 100 with a bandwidth portion (BWP) consisting of consecutive PRBs. The UE 100 transmits and receives data and control signals in the active BWP. For example, up to four BWPs can be configured for the UE 100. Each BWP may have a different subcarrier spacing or may overlap in frequency. When multiple BWPs are configured for the UE 100, the base station 200 can specify which BWP to activate by controlling the downlink. This allows the base station 200 to dynamically adjust the UE bandwidth according to the amount of data traffic of the UE 100, etc., and can reduce UE power consumption.

[0025] For example, base station 200 can configure up to three control resource sets (CORESETs) for each of up to four BWPs on the serving cell. A CORESET is a radio resource for control information to be received by UE 100. Up to 12 CORESETs can be configured for UE 100 on the serving cell. Each CORESET has an index of 0 to 11. For example, a CORESET consists of six resource blocks (PRBs) and one, two, or three consecutive OFDM symbols in the time domain.

[0026] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of base station 200 via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resources to be allocated to UE 100.

[0027] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 200 via logical channels.

[0028] The PDCP layer performs header compression / decompression and encryption / decryption.

[0029] An SDAP (Service Data Adaptation Protocol) layer may be provided above the PDCP layer, which maps IP flows, which are units for QoS control by the core network, to radio bearers, which are units for QoS control by the AS (Access Stratum).

[0030] The RRC layer controls logical channels, transport channels, and physical channels according to the establishment, re-establishment, and release of radio bearers. RRC signaling for various settings is transmitted between the RRC layer of the UE 100 and the RRC layer of the base station 200. When there is an RRC connection between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in an RRC connected state. When there is no RRC connection between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in an RRC idle state. When the RRC connection between the RRC of the UE 100 and the RRC of the base station 200 is suspended, the UE 100 is in an RRC inactive state.

[0031] The NAS layer located above the RRC layer performs session management and mobility management for the UE 100. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the core network device 300 (AMF). Note that the UE 100 has an application layer and the like in addition to a radio interface protocol.

[0032] (Assumed scenario) 3 to 6, a description will be given of an assumed scenario in the mobile communication system 1 according to the embodiment.

[0033] The UE 100 in an RRC idle state or an RRC inactive state monitors paging from the base station 200. Specifically, the UE 100 checks whether or not there is paging addressed to the UE 100 by receiving a PDCCH (Physical Downlink Control Channel) from the base station 200. For example, the UE 100 may receive a paging message by receiving (decoding) downlink control information (DCI) on the PDCCH to which a cyclic redundancy check (CRC) (CRC parity bit) scrambled by a P-RNTI (Paging Radio Network Temporary Identifier) ​​is added. Here, the base station 200 may set the P-RNTI for the UE 100. Furthermore, the DCI may be in a DCI format used for scheduling a PDSCH (Physical Downlink Shared Channel). That is, the paging message may be transmitted on the PDSCH. Here, DCI to which a CRC (CRC parity bits) scrambled by the P-RNTI is added is also called paging DCI.

[0034] Here, in order to reduce power consumption, the UE 100 discontinuously monitors paging using discontinuous reception (DRX). Such a cycle for monitoring paging is called a DRX cycle. A frame in which the UE 100 should monitor paging is called a paging frame (PF), and a subframe in this PF in which the UE 100 should monitor paging is called a paging occasion (PO).

[0035] FIG. 3 shows an example of operation of an eDRX UE (ie, an eDRX user equipment) performing extended discontinues reception (eDRX).

[0036] eDRX is a technology that uses a longer DRX cycle than normal DRX in order to achieve further power saving of the UE 100. The UE 100 configured for DRX wakes up every DRX cycle to monitor the PDCCH, and when this monitoring ends, goes into a sleep state until the next DRX cycle. Therefore, by using a DRX cycle (hereinafter referred to as the "eDRX cycle") that is longer than normal DRX, the period during which the receiver of the UE 100 can be turned off becomes longer, thereby achieving further power saving.

[0037] In normal DRX, the DRX cycle is set to a time length of, for example, 32 radio frames, 64 radio frames, 128 radio frames, or 256 radio frames. In contrast, the eDRX cycle used in eDRX is set to a time length that is an integer multiple of a hyperframe consisting of 1024 radio frames.

[0038] On the other hand, a UE 100 configured with eDRX (i.e., an eDRX UE) attempts to receive paging in a specific hyperframe (PH: Paging Hyperframe) for each eDRX cycle. The time interval for monitoring paging is called a PTW (Paging Timing Window), and during the PTW period, the UE monitors a PO (Paging Occasion) according to normal DRX.

[0039] FIG. 4 shows an example of operation for a UE in RRC idle or RRC inactive state.

[0040] As shown in FIG. 4, in step S11, base station 200 transmits an SSB to UE 100. The SSB is another example of a downlink reference signal. The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), and a demodulation reference signal (DMRS). For example, the SSB may be composed of four consecutive OFDM symbols in the time domain. Alternatively, the SSB may be composed of 240 consecutive subcarriers (i.e., 20 resource blocks) in the frequency domain. The PBCH is a physical channel that carries a master information block (MIB). UE 100 performs time and frequency synchronization by receiving the SSB.

[0041] In step S12, UE 100 monitors and receives paging in PO. Note that UE 100 maintains a wake-up state from the time of receiving SSB in step S11 until PO. Therefore, the longer the time from the time of receiving SSB to the time of PO, the longer the wake-up duration becomes, and the more power consumption of UE 100 increases.

[0042] In 3GPP, discussions are underway to standardize a technology for reducing power consumption for UE 100 in an RRC idle state or an RRC inactive state. In such a technology, it is being considered to make a TRS resource (also referred to as a "TRS opportunity") configured for UE 100 in an RRC connected state available for UE 100 in an RRC idle state or an RRC inactive state. Specifically, base station 200 broadcasts a TRS resource configuration, which is a configuration for the TRS resource, by a system information block (also referred to as "broadcast information").

[0043] 5 shows an example of an operation for the UE 100 in the RRC idle state or the RRC inactive state to receive the TRS. Note that the TRS may be a CSI-RS (Channel State Information - Reference Signal) used for tracking purposes. That is, in this embodiment, the TRS resource may include the CSI-RS resource.

[0044] In step S21, base station 200 transmits a specific system information block (hereinafter, sometimes referred to as a specific SIB) including TRS resource configuration. Specifically, base station 200 transmits a system information block including one or more TRS resource configuration parameter sets on a broadcast channel. The specific system information block may be an existing system information block other than system information block type 1 (SIB1), or may be a newly introduced type of system information block. UE 100 receives the specific system information block.

[0045] The UE 100 configures a TRS resource set according to a TRS resource configuration included in a specific system information block. Specifically, the UE 100 configures a TRS resource set based on one or more TRS resource configuration parameter sets.

[0046] Here, the TRS resource configuration for configuring a TRS for UE 100 in an RRC idle state or an RRC inactive state is CSI-ResourceConfig / NZP-CSI-RS-ResourceSet, and may include bwp-ID, resourceType, trs-Info, repetition, powerControlOffset, powerControlOffsetSS, recurrenceDomainAllocation, firstOFDMSymbolInTimeDomain, Density, startingRB, nrofRBs, and subcarrierSpacing as respective parameters (see 3GPP TS38.331). The TRS resource configuration may be only a part of the parameter set configured for UE 100 in an RRC connected state.

[0047] In step S22, the base station 200 transmits downlink control information (DCI) to the UE 100. The UE 100 receives the DCI from the base station 200.

[0048] The DCI includes an availability indicator that indicates whether the TRS is transmitted based on the configured TRS resource set. The availability indicator may be referred to as a TRS availability indicator.

[0049] Based on the availability indicator, the UE 100 determines whether or not a TRS is to be transmitted based on the configured TRS resource set. If the UE 100 determines that a TRS is to be transmitted, the UE 100 executes the process of step S23. If the UE 100 determines that a TRS is not to be transmitted, the UE 100 does not need to execute the process of step S23. In this case, the UE 100 may execute the process of receiving an SSB.

[0050] In this way, base station 200 can flexibly control time-frequency synchronization based on TRS by notifying UE 100 by DCI whether or not to transmit TRS.

[0051] In step S23, base station 200 transmits a TRS. UE 100 receives the TRS using the TRS resource configuration. By receiving the TRS, UE 100 can achieve time and frequency synchronization without receiving an SSB.

[0052] In step S24, UE 100 monitors and receives paging in the PO. Note that UE 100 maintains a wake-up state from when it receives the TRS in step S21 until the PO. If the time from when it receives the TRS to when it receives the PO is short, the wake-up duration is shortened, and the power consumption of UE 100 is reduced. Furthermore, by not receiving SSB, UE 100 can reduce the power consumption associated with receiving SSB.

[0053] Here, the availability indicator field including the availability indicator is a variable-length field indicated by a maximum of 6 bits. However, the current 3GPP specifications do not specify a method for the UE 100 to determine the number of bits of the availability indicator field. As a result, there is a risk that the UE 100 may erroneously identify the availability indicator field and may not be able to correctly determine whether or not a TRS is to be transmitted based on a configured TRS resource set. In one embodiment described later, an operation for enabling correct determination of whether or not a TRS is to be transmitted based on a configured TRS resource set will be described.

[0054] Furthermore, when the specific SIB includes a TRS resource set for a general UE that performs DRX and a TRS resource set for an eDRX UE that performs eDRX, it is unclear how the UE 100 determines the number of bits of the availability indicator field. As a result, the UE 100 may erroneously identify the availability indicator field and may not be able to correctly determine whether or not a TRS is to be transmitted based on the configured TRS resource set. In one embodiment described later, an operation for enabling correct determination of whether or not a TRS is to be transmitted based on the configured TRS resource set will be described.

[0055] (Configuration of user device) The configuration of the UE 100 according to the embodiment will be described with reference to Fig. 6. The UE 100 includes a communication unit 110 and a control unit 120.

[0056] The communication unit 110 performs wireless communication with the base station 200 by transmitting and receiving radio signals to and from the base station 200. The communication unit 110 has at least one transmission unit 111 and at least one reception unit 112. The transmission unit 111 and the reception unit 112 may be configured to include multiple antennas and RF circuits. The antenna converts a signal into radio waves and radiates the radio waves into space. The antenna also receives radio waves in space and converts the radio waves into a signal. The RF circuit performs analog processing of the signal transmitted and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

[0057] The control unit 120 performs various controls in the UE 100. The control unit 120 controls communication with the base station 200 via the communication unit 110. The operations of the UE 100 described above and below may be controlled by the control unit 120. The control unit 120 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operations of the control unit 120. The control unit 120 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of a RAN protocol stack. The memory stores programs executed by the processor, parameters related to the programs, and data related to the programs. The memory may include at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), and a flash memory. All or a part of the memory may be included in the processor.

[0058] The UE 100 configured as described above performs time-frequency synchronization in the downlink using the TRS. In the UE 100, the receiver 112 receives from the base station 200 a specific SIB including a TRS resource configuration and a DCI including an availability indicator indicating whether the TRS is to be transmitted based on the TRS resource set configured by the TRS resource configuration. The controller 120 determines whether the TRS is to be transmitted based on the configured TRS resource set based on the availability indicator. The controller 120 determines the number of bits of the availability indicator field in which the availability indicator is stored based on the number of TRS resource set groups specified by the TRS resource configuration. This allows the UE 100 to identify the availability indicator field and correctly determine whether the TRS is to be transmitted based on the configured TRS resource set.

[0059] (Base station configuration) The configuration of the base station 200 according to the embodiment will be described with reference to Fig. 7. The base station 200 includes a communication unit 210, a network communication unit 220, and a control unit 230.

[0060] The communication unit 210 receives a radio signal from the UE 100 and transmits the radio signal to the UE 100, for example. The communication unit 210 has at least one transmission unit 211 and at least one reception unit 212. The transmission unit 211 and the reception unit 212 may be configured to include an RF circuit. The RF circuit performs analog processing of a signal transmitted and received via an antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, etc.

[0061] The network communication unit 220 transmits and receives signals to and from the network. For example, the network communication unit 220 receives signals from adjacent base stations connected via an Xn interface, which is an interface between base stations, and transmits the signals to the adjacent base stations. The network communication unit 220 also receives signals from the core network device 300 connected via an NG interface, and transmits the signals to the core network device 300.

[0062] The control unit 230 performs various controls in the base station 200. The control unit 230 controls, for example, communication with the UE 100 via the communication unit 210. The control unit 230 also controls, for example, communication with a node (e.g., a neighboring base station, the core network device 300) via the network communication unit 220. The operations of the base station 200 described above and below may be operations controlled by the control unit 230. The control unit 230 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operations of the control unit 230. The control unit 230 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of a protocol stack of the RAN. The memory stores the program executed by the processor, parameters related to the program, and data related to the program. All or a part of the memory may be included in the processor.

[0063] The base station 200 configured as described above performs radio communication with the UE 100, which performs time-frequency synchronization in the downlink using TRS. In the base station 200, the transmitter 211 transmits to the UE 100 an SIB including a TRS resource configuration and a DCI including an availability indicator indicating whether a TRS is to be transmitted based on the TRS resource set configured by the TRS resource configuration. The controller 230 determines the number of bits of an availability indicator field in which the availability indicator is stored, based on the number of TRS resource set groups defined by the TRS resource configuration. This allows the UE 100 to identify the availability indicator field and correctly determine whether a TRS is to be transmitted based on the configured TRS resource set.

[0064] (First operation example) A first operation example will be described with reference to Figures 8 to 11. This operation is based on the above-described configuration and operation, and therefore, previous explanations may be omitted.

[0065] In step S101, the transmitter 211 of the base station 200 transmits a specific SIB including a TRS resource configuration. The receiver 112 of the UE 100 receives the specific SIB. Hereinafter, the specific SIB may include a configuration of a TRS (e.g., CSI-RS) for tracking that can be used by the UE 100 in an RRC idle state or an RRC inactive state. The specific SIB may be referred to as SIBXX.

[0066] The specific SIB includes a TRS resource configuration. As shown in FIG. 9, the specific SIB may include, as the TRS resource configuration, a TRS resource set configuration (trs-ResourceSetConfig-r17 / TRS-ResourceSetConfig-r17), an individual TRS configuration list (nzp-CSI-RS-ResourceListForTracking-r17), and a common TRS configuration (nzp-CSI-RS-ResourceCommon-r17 / NZP-CSI-RS-ResourceCommon-r17) (see E91 in FIG. 9). Note that "-r17" means that the information elements are introduced in Release 17 of the 3GPP technical specifications, but these information elements may be introduced in Release 18 or later.

[0067] A TRS resource set configuration (TRS-ResourceSetConfig-r17) may be configured with one or more TRS resource set groups (TRS-ResourceSetGroup-r17) (see E92 in FIG. 9). Specifically, the TRS resource set configuration may be configured in the form of a list including the TRS resource set groups. In this way, the TRS resource set configuration may specify the TRS resource set groups.

[0068] A TRS resource set group may be a list of TRS resource sets (NZP-CSI-RS-ResourceSetSIB-r17) (see E93 in FIG. 9). Thus, a TRS resource set group is composed of grouped TRS resource sets. That is, a TRS resource set configuration may be a parameter for grouping TRS resource sets.

[0069] The TRS resource set may be a set of a TRS resource set identifier (nzp-CSI-ResourceSetId-r17 / NZP-CSI-RS-ResourceSetId) and TRS resources (nzp-CSI-RS-Resources-r17). Note that the TRS resources may be a list of TRS resource identifiers (NZP-CSI-RS-ResourceId) associated with the TRS resources.

[0070] The dedicated TRS configuration list is a list of dedicated TRS configurations (NZP-CSI-RS-ResourceSIB-r17). As shown in Fig. 10, the dedicated TRS configuration may include an identifier of the TRS resource (nzp-CSI-RS-ResourceId / NZP-CSI-RS-ResourceId), a parameter (frequencyDomainAllocation) indicating allocation of the TRS in the frequency direction, a parameter (firstOFDMSymbolInTimeDomain) indicating allocation of the TRS in the time direction, and a parameter (scramblingID / ScramblingId) indicating a scrambling identifier of the TRS.

[0071] The common TRS configuration may be a set of parameters commonly applied to all individual TRS configurations. As shown in Fig. 10, the common TRS configuration may include a parameter (csi-FrequencyOccupation-r17 / CSI-FrequencyOccupation) indicating the frequency domain occupation range of the TRS, a parameter (powerControlOffsetSS-r17) indicating the power offset of the TRS relative to the synchronization signal, parameters (periodicityAndOffset-r17 / CSI-ResourcePeriodicityAndOffsetSIB-r17) indicating the periodicity and time offset of the TRS, and a parameter (qcl-InfoForTracking-r17) related to the QCL of the TRS.

[0072] In step S102, control unit 120 of UE 100 determines the number of bits of the availability indicator field. Specifically, control unit 120 of UE 100 determines the number of bits of the availability indicator field based on the number of TRS resource set groups. When the TRS resource set configuration is configured in a list format including TRS resource set groups, control unit 120 of UE 100 determines the number of bits of the availability indicator field based on the number of entries of one or more TRS resource set groups in the list format. When the number of entries of the TRS resource set group (which may be the entry size) is N, control unit 120 of UE 100 determines that the number of bits of the availability indicator field is N.

[0073] In step S103, the transmitter 211 of the base station 200 transmits the DCI to the UE 100. The receiver 112 of the UE 100 receives the DCI from the base station 200.

[0074] The DCI may be DCI format 1_0 used for scheduling a PDSCH in one downlink cell. As shown in FIG. 11, DCI format 1_0 may include an availability indicator (TRS availability indication) (see E111 in FIG. 11). The availability indicator may be stored in an availability indicator field in DCI format 1_0. The availability indicator may be transmitted by DCI format 1_0 CRC-scrambled by a paging-radio network temporary identifier (P-RNTI).

[0075] The availability indicator is a bitmap of 1 to 6 bits when the TRS resource set configuration (TRS-ResourceSetConfig) is set. Therefore, the availability indicator field is represented by a bit number of 1 to 6. On the other hand, the availability indicator (i.e., the availability indicator field) is 0 bits when the TRS resource set configuration is not set.

[0076] The bit positions of the bitmap constituting the availability indicator correspond to the entries of the TRS resource set group configured in the TRS resource set configuration. Specifically, the first bit or the leftmost bit corresponds to the first entry of the TRS resource set group configured in the TRS resource set configuration, and the second bit corresponds to the second entry of the TRS resource set group configured in the TRS resource set configuration. The number of bits in the availability indicator field corresponds to the number of TRS resource set groups configured by the TRS resource set configuration.

[0077] Furthermore, the DCI may be DCI format 2_7 used to notify one or more UEs 100 of a paging early indicator and an availability indicator. As shown in FIG. 11, DCI format 2_7 may include an availability indicator (see E112 in FIG. 11). The availability indicator may be stored in an availability indicator field in DCI format 2_7. The availability indicator may be transmitted by DCI format 2_7 CRC-scrambled by a paging early indicator-radio network temporary identifier (PEI-RNTI).

[0078] In step S104, control unit 120 of UE 100 determines whether or not a TRS is to be transmitted.

[0079] The control unit 120 of the UE 100 identifies the availability indicator (or the availability indicator field) based on the determined number of bits of the availability indicator. The control unit 120 determines whether or not the TRS is to be transmitted based on the identified availability indicator.

[0080] Specifically, when the value at a bit position of a bitmap constituting the availability indicator is a predetermined value (e.g., "1"), control unit 120 of UE 100 determines that the TRS of the TRS resource set group of the corresponding entry is being transmitted. On the other hand, when the value at the bit position is a value different from the predetermined value (e.g., "0"), control unit 120 determines that the TRS of the TRS resource set group of the corresponding entry is not being transmitted.

[0081] Control unit 120 determines whether a TRS is transmitted based on the configured TRS resource set, based on the value of the bit position corresponding to the entry of the TRS resource set group to which the TRS resource set configured in UE 100 belongs. If control unit 120 determines that a TRS is transmitted based on the configured TRS resource set, it executes the process of step S105. If UE 100 determines that a TRS is not transmitted, it does not need to execute the process of step S105. In this case, UE 100 may execute the process of receiving an SSB.

[0082] Steps S105 and S106 correspond to steps S23 and S24.

[0083] As described above, transmitting unit 211 of base station 200 transmits to UE 100 an SIB including a TRS resource configuration and DCI including an availability indicator indicating whether a TRS is to be transmitted based on the TRS resource set configured by the TRS resource configuration. Control unit 230 of base station 200 determines the number of bits of an availability indicator field in which the availability indicator is stored, based on the number of TRS resource set groups defined by the TRS resource configuration. Receiving unit 112 of UE 100 receives from base station 200 an SIB including a TRS resource configuration and DCI including an availability indicator indicating whether a TRS is to be transmitted based on the TRS resource set configured by the TRS resource configuration. Control unit 120 determines whether a TRS is to be transmitted based on the configured TRS resource set, based on the availability indicator. Control unit 120 determines the number of bits of an availability indicator field in which the availability indicator is stored, based on the number of TRS resource set groups defined by the TRS resource configuration. This allows the UE 100 to identify the availability indicator field and correctly determine whether or not a TRS is to be transmitted based on the configured TRS resource set.

[0084] Furthermore, the TRS resource configuration may include a TRS resource set configuration consisting of one or more TRS resource set groups. The control unit 120 may determine the number of bits of the availability indicator field based on the number of TRS resource set groups that make up the TRS resource set configuration. The control unit 120 can determine the number of bits of the availability indicator field based on the TRS resource set configuration and correctly determine whether a TRS is to be transmitted based on the configured TRS resource set.

[0085] Furthermore, the TRS resource set configuration may be configured in a list format including one or more TRS resource set groups. The control unit 120 may determine the number of bits of the availability indicator field based on the number of entries of one or more TRS resource set groups in the list format. This allows the control unit 120 to determine the number of bits of the availability indicator field even if the TRS resource set configuration does not include an identifier for identifying the group, thereby reducing the amount of information in the TRS resource configuration.

[0086] Furthermore, bit positions of a bitmap constituting the availability indicator may be associated with entries. When a value at a bit position is a predetermined value, the control unit 120 may determine that a TRS of the TRS resource set group of the corresponding entry is being transmitted. This allows the control unit 120 to determine whether a TRS is being transmitted based on a TRS resource set included in the TRS resource set group of the corresponding entry. As a result, it is possible to prevent the UE 100 from attempting to receive a TRS even when a TRS is not being transmitted.

[0087] (Second operation example) A second operation example will be described with reference to Figures 8, 12, and 13. Descriptions similar to those of the above operation examples will be omitted as appropriate. In the second operation example, the UE 100 determines the number of bits of the availability indicator field based on the group identifier.

[0088] In step S101, the transmitter 211 of the base station 200 transmits the following specific SIB: The receiver 112 of the UE 100 receives the specific SIB.

[0089] As shown in FIG. 12, the TRS resource set configuration (trs-ResourceSetConfig-r17) included in a specific SIB may be a list of TRS resource sets (NZP-CSI-RS-ResourceSetSIB-r17) (see E121 in FIG. 12). The TRS resource set may include a TRS resource set identifier (nzp-CSI-ResourceSetId-r17 / NZP-CSI-RS-ResourceSetId), TRS resources (nzp-CSI-RS-Resources-r17), and a group identifier (trs-ResourceSetGroupId-r17) that identifies a TRS resource set group (see E122 in FIG. 12). Thus, one or more TRS resource sets are associated with a group identifier. The group identifier is the identifier (ID) of the TRS resource set group to which the associated TRS resource set belongs. Thus, each TRS resource set group is composed of TRS resource sets with the same corresponding group identifier value. Note that the base station 200 (network 10) configures TRS resource set groups with consecutive IDs starting from 0.

[0090] In step S102, control unit 120 of UE 100 determines the number of bits of the availability indicator field based on the number of group identifiers. When the number of group identifiers is N, control unit 120 determines the number of bits of the availability indicator field to be N.

[0091] In the DCI transmitted in step S103, each code point of the "availability indicator" in the DCI field, i.e., each bit position of the availability indicator bitmap, is associated with a TRS resource set group ID. Specifically, the first bit or the leftmost bit of the bitmap constituting the availability indicator corresponds to TRS resource set group ID 0, and the second bit corresponds to TRS resource set group ID 1 (see E131 and E132 in FIG. 13).

[0092] In step S104, the control unit 120 of the UE 100 determines whether or not a TRS is being transmitted based on the configured TRS resource set based on the value of the bit position corresponding to the group identifier that identifies the TRS resource set group to which the TRS resource set configured in the UE 100 belongs.

[0093] As described above, the TRS resource configuration may include a TRS resource set configuration configured with one or more TRS resource sets associated with a group identifier. The control unit 120 may determine the number of bits of the availability indicator field based on the number of group identifiers. This allows the UE 100 to identify the availability indicator field and correctly determine whether or not to transmit a TRS based on the configured TRS resource set.

[0094] (Third operation example) A third operation example will be described with reference to Figures 8 and 14. Descriptions similar to those of the above operation examples will be omitted as appropriate. In the third operation example, one or more TRS resource set groups and group identifiers are associated with each other in a format different from that of the second operation example.

[0095] As shown in Fig. 14, the specific SIB includes a TRS resource configuration, as in the first operation example. In the TRS resource set configuration (trs-ResourceSetConfig-r17 / TRS-ResourceSetConfig-r17) included in the TRS resource configuration, one or more TRS resource set groups (TRS-ResourceSetGroup-r17) are associated with group identifiers (trs-ResourceSetGroupId-r17) (E141 in Fig. 14). Therefore, the TRS resource configuration includes a TRS resource set configuration in which one or more TRS resource set groups are associated with group identifiers.

[0096] In step S102, the control unit 120 of the UE 100 determines the number of bits of the availability indicator field based on the number of group identifiers, as in the second operation example, which allows the UE 100 to identify the availability indicator field and correctly determine whether or not a TRS is to be transmitted based on the configured TRS resource set.

[0097] (Fourth operation example) A fourth operation example will be described with reference to Figures 15 and 16. Descriptions similar to those of the above operation examples will be omitted as appropriate. In the fourth operation example, the TRS resource configuration includes separate TRS resource set groups for general UEs performing DRX and eDRX UEs.

[0098] 15, in step S201, the transmitter 211 of the base station 200 transmits the following specific SIB: The receiver 112 of the UE 100 receives the specific SIB.

[0099] The specific SIB includes a first TRS resource set group for a general UE performing DRX and a second TRS resource set group for an eDRX UE performing eDRX. In this operation example, different group identifiers are assigned to the first TRS resource set group and the second TRS resource set group.

[0100] 16, the first TRS resource set group includes a TRS resource set group configured by TRS resource sets associated with group identifier #0 and a TRS resource set group configured by TRS resource sets associated with group identifier #1. The second TRS resource set includes a TRS resource set group configured by TRS resource sets associated with group identifier #2.

[0101] The TRS resource sets associated with group identifier #0 and group identifier #1 are TRS resource sets for normal UEs, and the TRS resource sets associated with group identifier #2 are TRS resource sets for eDRX UEs.

[0102] The specific SIB may include a group identifier and information indicating whether a TRS resource set associated with the group identifier is for eDRX UEs (or for normal UEs). Alternatively, information indicating whether the TRS resource set is for eDRX UEs (or for normal UEs) may be associated with each TRS resource set. Alternatively, information indicating whether the TRS resource set associated with the group identifier is for eDRX UEs (or for normal UEs) may be associated with the group identifier. Control unit 120 of UE 100 can determine whether each TRS resource set is for normal UEs or eDRX UEs based on the information.

[0103] The specific SIB may include duration information indicating the validity duration of the availability indicator indicated in the availability indicator field for each of the first TRS resource set and the second TRS resource set. The duration information may include first duration information that is the validity duration of the availability indicator for the first TRS resource set and second duration information that is the validity duration of the availability indicator for the second TRS resource set. The control unit 120 can determine the validity duration of the availability indicator for the first TRS resource set based on the first duration information. Similarly, the control unit 120 can determine the validity duration of the availability indicator for the second TRS resource set based on the second duration information.

[0104] The validity period for the first TRS resource set may be an integer multiple of a first time unit, which may be, for example, one default paging cycle.

[0105] The validity period for the second TRS resource set may be an integer multiple of a second time unit that is longer than the first time unit. The first time unit may be, for example, an eDRX cycle or an acquisition period (specifically, an eDRX acquisition period) that triggers the UE 100 configured for eDRX to acquire an updated SIB.

[0106] In step S202, control unit 120 of UE 100 determines the number of bits of the availability indicator field based on the total number of the first TRS resource set group and the second TRS resource set group.

[0107] For example, the control unit 120 may determine the number of bits of the availability indicator field based on the total number of group identifiers of the first TRS resource set group and the second TRS resource set group. In the example of Fig. 16, the control unit 120 may determine the number of bits of the availability indicator field to be 3, which is the total (i.e., total value) of the number of group identifiers of the first TRS resource set group (2) and the number of group identifiers of the second TRS resource set group (1).

[0108] Steps S203 to S206 are the same as steps S103 to S106.

[0109] For example, when a first TRS resource set associated with group identifier #0 is configured, the control unit 120 determines whether a TRS is being transmitted based on the value of the first bit position in the bitmap that constitutes the availability indicator. Similarly, when a second TRS resource set associated with group identifier #2 is configured, the control unit 120 determines whether a TRS is being transmitted based on the value of the third bit position in the bitmap that constitutes the availability indicator.

[0110] Note that when UE 100 is a normal UE, control unit 120 receives a TRS based on the first TRS resource set. When UE 100 is an eDRX UE, control unit 120 receives a TRS based on the second TRS resource set. For example, when a DRX setting is configured (for example, a DRX cycle is applied), control unit 120 determines that UE 100 is a normal UE. On the other hand, when eDRX setting is configured (for example, an eDRX cycle is applied), control unit 120 determines that UE 100 is an eDRX UE.

[0111] As described above, the control unit 120 may determine the number of bits of the availability indicator field based on the total number of the first TRS resource set group and the second TRS resource set group. Furthermore, the control unit 120 may determine the number of bits of the availability indicator field based on the total number of group identifiers of the first TRS resource set group and the second TRS resource set group. This allows the UE 100 to identify the availability indicator field and correctly determine whether or not to transmit a TRS based on the configured TRS resource set, even if a specific SIB includes a TRS resource set for a general UE that performs DRX and a TRS resource set for an eDRX UE that performs eDRX.

[0112] Furthermore, because different group identifiers are assigned to the first TRS resource set group and the second TRS resource set group, base station 200 (network 10) can determine whether to transmit a TRS transmitted based on the first TRS resource set and a TRS transmitted based on the second TRS resource set, respectively, allowing base station 200 to flexibly control TRS transmission.

[0113] Furthermore, receiving unit 112 receives from base station 200 a specific SIB including period information indicating the validity period of the availability indicator for each of the first TRS resource set and the second TRS resource set. This allows control unit 120 to grasp the validity period of the availability indicator for each of the first TRS resource set and the second TRS resource set, even if the specific SIB includes the first TRS resource set and the second TRS resource set. As a result, UE 100 can correctly determine whether or not to transmit a TRS based on the configured TRS resource set.

[0114] (5th operation example) A fifth operation example will be described with reference to Fig. 17. Descriptions similar to those of the above operation examples will be omitted as appropriate. In the fifth operation example, the UE 100 determines the number of bits of the availability indicator field based on the total number of the first TRS resource set group and the second TRS resource set group, whichever is larger.

[0115] As shown in FIG. 17, in this operation example, group identifiers are assigned individually to the first TRS resource set group and the second TRS resource set group.

[0116] 17, the first TRS resource set group includes a TRS resource set group configured by the TRS resource sets associated with group identifier #0 and a TRS resource set group configured by the TRS resource sets associated with group identifier #1. The second TRS resource set includes a TRS resource set group configured by the TRS resource sets associated with group identifier #0.

[0117] The TRS resource sets associated with group identifier #0 and group identifier #1 are TRS resource sets for normal UEs, and the TRS resource sets associated with group identifier #0 are TRS resource sets for eDRX UEs.

[0118] The control unit 120 of the UE 100 may determine the number of bits of the availability indicator field based on the total number of the first TRS resource set group and the second TRS resource set group that has the largest number of groups. The control unit 120 may determine the number of bits of the availability indicator field based on the total number of group identifiers of the groups that have the largest number of groups.

[0119] 16, the control unit 120 compares the number of group identifiers of the first TRS resource set group, which is 2, with the number of group identifiers of the second TRS resource set group, which is 1, and determines that the number of group identifiers of the first TRS resource set group is greater. The control unit 120 may determine that the number of bits of the availability indicator field is 2, which is the number of group identifiers of the first TRS resource set group that is greater.

[0120] As described above, the control unit 120 may determine the number of bits of the availability indicator field based on the total number of the first TRS resource set group and the second TRS resource set group, whichever is larger. Furthermore, the control unit 120 may determine the number of bits of the availability indicator field based on the total number of group identifiers, whichever is larger. This allows the UE 100 to identify the availability indicator field and correctly determine whether to transmit a TRS based on the configured TRS resource set, even when a specific SIB includes a TRS resource set for a general UE that performs DRX and a TRS resource set for an eDRX UE that performs eDRX.

[0121] Furthermore, since group identifiers are assigned individually to the first TRS resource set group and the second TRS resource set group, base station 200 (network 10) can assign a larger number of group identifiers to TRS resource set groups than in the fourth operation example, which allows base station 200 to configure TRS resource settings in a more detailed manner.

[0122] In this operation example, when the first TRS resource set group and the second TRS resource set group are assigned the same group identifier (for example, group identifier #0 in FIG. 16), control unit 230 of base station 200 determines whether to transmit both TRSs transmitted based on the first TRS resource set and the second TRS resource set assigned the same group identifier or not to transmit both TRSs. In other words, control unit 230 of base station 200 does not perform control such that a TRS based on one TRS resource set is transmitted and a TRS based on the other TRS resource set is not transmitted.

[0123] (6th operation example) A sixth operation example will be described with reference to Fig. 18. Descriptions similar to those of the above operation examples will be omitted as appropriate. In the sixth operation example, an operation in which the UE 100 determines the validity period of the availability indicator for the second TRS resource set group will be described.

[0124] The control unit 120 of the UE 100 may perform the following processing, for example, based on the reception of the specific SIB.

[0125] 18, in step S301, control unit 120 of UE 100 determines whether UE 100 is an eDRX UE. If UE 100 is an eDRX UE, control unit 120 executes the process of step S302. On the other hand, if UE 100 is not an eDRX UE, control unit 120 may end the process.

[0126] Note that, for example, when an eDRX setting is configured (for example, an eDRX cycle is applied), control unit 120 may determine that UE 100 is an eDRX UE. When a DRX setting is configured (for example, a DRX cycle is applied), control unit 120 may determine that UE 100 is not an eDRX UE.

[0127] In step S302, the control unit 120 determines whether the specific SIB includes second period information indicating the validity period of the availability indicator for the second TRS resource set. If the specific SIB includes the second period information, the control unit 120 executes the process of step S303. If the specific SIB does not include the second period information, the control unit 120 executes the process of step S304.

[0128] In step S303, the control unit 120 determines the validity period based on the second period information.

[0129] In step S304, the control unit 120 may determine the validity period based on the eDRX cycle or the eDRX acquisition period, which is an acquisition period that triggers the eDRX UE to acquire an updated SIB.

[0130] The control unit 120 may, for example, by default, consider the valid period to be the period up to the next eDRX cycle. Alternatively, the control unit 120 may, for example, by default, consider the valid period to be the period up to the boundary of the acquisition period.

[0131] As described above, when the UE 100 is an eDRX UE, if the specific SIB includes second period information, which is period information for eDRX UEs, the control unit 120 may determine the validity period based on the second period information. If the specific SIB does not include second period information, the control unit 120 may determine the validity period based on the eDRX cycle or the eDRX acquisition period. This allows the UE 100 to appropriately determine the validity period regardless of whether the specific SIB includes second period information. As a result, the control unit 120 can correctly determine whether or not a TRS is to be transmitted based on the configured TRS resource set.

[0132] (Other embodiments) The operational sequences (and operational flows) in the above-described embodiments do not necessarily have to be executed in chronological order according to the order depicted in the flow diagrams or sequence diagrams. For example, the steps in the operations may be executed in an order different from that depicted in the flow diagrams or sequence diagrams, or may be executed in parallel. Some of the steps in the operations may be deleted, or additional steps may be added to the processing. The operational sequences (and operational flows) in the above-described embodiments may be executed independently, or two or more operational sequences (and operational flows) may be executed in combination. For example, some steps in one operational flow may be added to another operational flow, or some steps in one operational flow may be replaced with some steps in another operational flow.

[0133] In the above-described embodiment, an NR-based mobile communication system has been described as an example of the mobile communication system 1. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system compliant with a TS of any of LTE (Long Term Evolution) or other generation systems (e.g., 6th generation) of the 3GPP standard. The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol termination for the UE 100 in LTE. The mobile communication system 1 may be a system compliant with a TS of a standard other than the 3GPP standard. The base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

[0134] A program may be provided that causes a computer to execute each process performed by UE 100 or base station 200. The program may be recorded in a computer-readable medium. Using the computer-readable medium, the program can be installed in a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM (Compact Disk Read Only Memory) or a DVD-ROM (Digital Versatile Disk Read Only Memory). Furthermore, circuits that execute each process performed by UE 100 or base station 200 may be integrated, and at least a part of UE 100 or base station 200 may be configured as a semiconductor integrated circuit (chip set, SoC (System On Chip)).

[0135] In the above embodiments, "transmit" may mean processing at least one layer in a protocol stack used for transmission, or may mean physically transmitting a signal wirelessly or via a wired connection. Alternatively, "transmit" may mean a combination of processing at least one layer and physically transmitting a signal wirelessly or via a wired connection. Similarly, "receive" may mean processing at least one layer in a protocol stack used for reception, or may mean physically receiving a signal wirelessly or via a wired connection. Alternatively, "receive" may mean a combination of processing at least one layer and physically receiving a signal wirelessly or via a wired connection. Similarly, "obtain / acquire" may mean obtaining information from stored information, obtaining information from information received from another node, or obtaining information by generating information. Similarly, the terms "based on" and "depending on / in response to" do not mean "based only on" or "depending only on," unless otherwise specified. The phrase "based on" means both "based only on" and "based at least in part on." Similarly, the phrase "depending on" means both "depending only on" and "depending at least in part on." Similarly, "include" and "comprise" do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Similarly, in this disclosure, "or" does not mean an exclusive or, but does mean a logical or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure 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 therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0136] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0137] (Addendum) The following additional notes are about the features of the above-described embodiment.

[0138] (Appendix 1) a receiving unit for receiving a system information block (SIB) from a base station; a control unit that determines the number of bits of a bitmap of a tracking reference signal (TRS) availability indicator in downlink control information (DCI), The control unit If the SIB includes a TRS resource set configuration, which is a list of TRS resource sets, determining the number of bits based on an identifier associated with the TRS resource set; If the TRS resource set configuration is not included in the SIB, the number of bits is determined to be 0. Communication equipment.

[0139] (Appendix 2) The identifier is included in the TRS resource set configuration. 2. The communication device of claim 1.

[0140] (Appendix 3) The DCI includes a cyclic redundancy check (CRC) scrambled by a paging radio network temporary identifier (P-RNTI). 3. The communication device according to claim 1 or 2.

[0141] (Appendix 4) The DCI includes a cyclic redundancy check (CRC) scrambled by a Paging Early Indicator-Radio Network Temporary Identifier (PEI-RNTI). 4. A communication device according to any one of claims 1 to 3.

[0142] (Appendix 5) The receiver receives the DCI from the base station; The control unit identifies the availability indicator of the received DCI based on the determined number of bits. 5. A communication device according to any one of claims 1 to 4.

[0143] (Appendix 6) The receiving unit receives a TRS based on the TRS resource set based on values ​​of bits of the bitmap of the determined number of bits. 6. A communication device according to any one of claims 1 to 5.

[0144] (Appendix 7) a transmitter for transmitting a system information block (SIB); a control unit that determines the number of bits of a bitmap of a tracking reference signal (TRS) availability indicator in downlink control information (DCI), The control unit If the SIB does not include a TRS resource set configuration, which is a list of TRS resource sets, determining the number of bits based on an identifier associated with the TRS resource set; If the TRS resource set configuration is not included in the SIB, the number of bits is determined to be 0. Base station.

[0145] (Appendix 8) 1. A communication method performed in a communication device, comprising: receiving a system information block (SIB) from a base station; determining a number of bits of a bitmap of a tracking reference signal (TRS) availability indicator in downlink control information (DCI); In the determining step, If the SIB includes a TRS resource set configuration, which is a list of TRS resource sets, determining the number of bits based on an identifier associated with the TRS resource set; If the TRS resource set configuration is not included in the SIB, the number of bits is determined to be 0. Communication method.

Claims

1. a receiving unit (112) for receiving downlink control information (DCI) from a base station; a control unit (120) that determines the number of bits of a bitmap of an availability indicator of a tracking reference signal (TRS) included in the DCI; When the control unit receives a TRS resource set configuration for configuring resources for the TRS from the base station, the control unit determines the number of bits of the availability indicator bitmap based on an identifier associated with the resources for the TRS included in the TRS resource set configuration; The receiving unit receives the TRS from the base station in resources of the TRS based on values ​​of bits of the availability indicator bitmap of the determined number of bits. A communication device (100).

2. The control unit determines the number of bits to be 0 when the TRS resource set configuration is not received. The communication device according to claim 1 .

3. the receiving unit receives information regarding a validity period of the availability indicator from the base station; the control unit determines a validity period of the availability indicator based on information relating to the validity period of the availability indicator; The time unit of the validity period is one default paging cycle.

3. The communication device according to claim 1 or 2.

4. The DCI is accompanied by a cyclic redundancy check (CRC) scrambled by a paging radio network temporary identifier (P-RNTI).

3. The communication device according to claim 1 or 2.

5. The DCI includes a cyclic redundancy check (CRC) scrambled by a Paging Early Indicator - Radio Network Temporary Identifier (PEI-RNTI).

3. The communication device according to claim 1 or 2.

6. A transmitter (211) for transmitting downlink control information (DCI) to a communication device (100), When the transmitter transmits a TRS resource set configuration for configuring resources for the TRS to the communication device, the transmitter transmits the TRS to the communication device in the resources for the TRS based on bit values ​​of a bitmap of an availability indicator for the TRS, the number of bits of which is based on an identifier associated with the resources for the TRS included in the TRS resource set configuration. Base station (200).

7. If the TRS resource set configuration is not transmitted, the number of bits is 0. The base station of claim 6.

8. the transmitting unit transmits information regarding a validity period of the availability indicator to the communication device; and determining, by the communication device, the validity period of the availability indicator based on information about the validity period of the availability indicator. The time unit of the validity period is one default paging cycle. The base station according to claim 6 or 7.

9. The DCI is accompanied by a cyclic redundancy check (CRC) scrambled by a paging radio network temporary identifier (P-RNTI). The base station according to claim 6 or 7.

10. The DCI includes a cyclic redundancy check (CRC) scrambled by a Paging Early Indicator - Radio Network Temporary Identifier (PEI-RNTI). The base station according to claim 6 or 7.

11. 1. A communication method performed in a communication device, comprising: receiving downlink control information (DCI) from a base station; determining a number of bits of a bitmap of a tracking reference signal (TRS) availability indicator included in the DCI; receiving the TRS from the base station in resources of the TRS based on values ​​of bits in the availability indicator bitmap of the determined number of bits; In the determining step, when a TRS resource set configuration for configuring resources for the TRS is received from the base station, the number of bits of the availability indicator bitmap is determined based on an identifier associated with the resources for the TRS included in the TRS resource set configuration. Communication method.

12. In the determining step, if the TRS resource set configuration is not received, the number of bits is determined to be 0. The communication method according to claim 11.

13. receiving information regarding a validity period of the availability indicator from the base station; determining a validity period of the availability indicator based on information about a validity period of the availability indicator; The time unit of the validity period is one default paging cycle.

13. A communication method according to claim 11 or 12.

14. The DCI is accompanied by a cyclic redundancy check (CRC) scrambled by a paging radio network temporary identifier (P-RNTI).

13. A communication method according to claim 11 or 12.

15. The DCI includes a cyclic redundancy check (CRC) scrambled by a Paging Early Indicator - Radio Network Temporary Identifier (PEI-RNTI).

13. A communication method according to claim 11 or 12.

Images