Terminal device, base station device, and communication system

Abstract

The present invention comprises: a receiving unit that receives, from a first base station device forming a first cell, a first signal that includes first configuration information for requesting first system information from a second base station device forming a second cell; a transmitting unit that transmits a second signal to the second base station device in accordance with the first configuration information; and a control unit that, according to a reference time and information regarding a time offset from the reference time, determines a first time as the start timing of a monitoring window for the first system information transmitted from the second base station device, and controls reception of the first system information transmitted from the second base station device so as to occur within the monitoring window.

Description

Terminal device, base station device, and communication system

[0001] The present invention relates to a terminal device, a base station device, and a communication system.

[0002] In the current network, the traffic of mobile terminals (smartphones and feature phones) occupies most of the network resources. Also, the traffic used by mobile terminals tends to increase in the future.

[0003] Also, in addition to the traffic used by mobile terminals, for example, the deployment of IoT (Internet of Things) services (for example, traffic systems, smart meters, monitoring systems for devices, etc.) is being carried out. Therefore, the network is required to support services with various requirement conditions. To support such various services, for example, in the communication standards of 5th generation mobile communication (5G or NR (New Radio)) (for example, Non-Patent Documents 1 to 14), support for many use cases classified into eMBB (Enhanced Mobile BroadBand), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications) is assumed, and the standards have been formulated.

[0004] In 3GPP (3rd Generation Partnership Project (registered trademark)), the extended technologies of the above communication standards are continuously studied and standardized. Currently in 3GPP, as a technology for suppressing the power of the network, the NES (Network Energy Savings) technology is being studied (Non-Patent Document 15).

[0005] One of the technologies being considered to realize NES is On-Demand SIB1. On-Demand SIB1 is a technology that reduces the power consumption of base station equipment by making SIB1 (System Information Block Type 1), which is one of the system information (system information) that base station equipment broadcasts to terminal equipment within a cell as information used in common, transmitted only when requested by terminal equipment (on-demand transmission). Hereinafter, cells (base stations) that support NES functions such as On-Demand SIB1, that is, cells that support NES functions, will also be called NES cells.

[0006] 3GPP TS 37.324 V18.0.03GPP TS 37.340 V18.4.03GPP TS 38.201 V18.0.03GPP TS 38.202 V18.4.03GPP TS 38.211 V18.5.03GPP TS 38.212 V18.5.03GPP TS 38.213 V18.5.03GPP TS 38.214 V18.5.03GPP TS 38.215 V18.4.03GPP TS 38.300 V18.4.03GPP TS 38.321 V18.4.03GPP TS 38.322 V18.2.03GPP TS 38.323 V18.4.03GPP TS 38.331 V18.4.0RP-242354

[0007] By the way, discussions on On-demand SIB1 have just begun, and the detailed specifications have not yet been decided. For example, after a terminal device sends a transmission request for On-demand SIB1 to an NES cell, the detailed specifications regarding the monitoring of SIB1 have not yet been decided.

[0008] The disclosed technology, made in view of the foregoing, provides a method for a terminal to receive an On-demand SIB1 transmitted from an NES cell.

[0009] In one aspect, the system includes: a receiving unit that receives a first signal from a first base station device forming a first cell, which includes first setting information for requesting first system information from a second base station device forming a second cell; a transmitting unit that transmits a second signal to the second base station device according to the first setting information; and a control unit that determines a first time which is the start timing of a monitoring window for the first system information transmitted from the second base station device, according to a reference time and time offset information from the reference time, and controls the system to receive the first system information transmitted from the second base station device within the monitoring window.

[0010] According to the above-described embodiment, the terminal can receive On-demand SIB1 transmitted from the NES cell.

[0011] Figure 1 is a diagram showing an example of a wireless communication system in Embodiment 1. Figure 2 is a diagram showing an example of a functional configuration block diagram of a base station in the wireless communication system of Embodiment 1. Figure 3 is a diagram showing an example of a functional configuration block diagram of a terminal in the wireless communication system of Embodiment 1. Figure 4 is a diagram showing an example of a sequence of the wireless communication system in Embodiment 1. Figure 5 is a diagram showing an example of the start timing of the monitoring window of On-demand SIB1. Figure 6 is a diagram showing an example of the transmission of the third signal. Figure 7 is a diagram showing an example of the start timing of the monitoring window of On-demand SIB1. Figure 8 is a diagram showing an example of the format of the information contained in the third signal. Figure 9 is a diagram showing an example of the format of the information contained in the third signal. Figure 10 is a diagram showing an example of the format of the information contained in the third signal. Figure 11 is a diagram showing an example of the format of the information contained in the third signal. Figure 12 is a diagram showing an example of the start timing of the monitoring window of On-demand SIB1. Figure 13 is a diagram showing an example of a method for determining the start timing or reference time of the monitoring window of On-demand SIB1. Figure 14 shows an example of the start timing of the monitoring window for On-demand SIB1. Figure 15 shows an example of the base station hardware configuration. Figure 16 shows an example of the terminal hardware configuration.

[0012] Hereinafter, this embodiment will be described in detail with reference to the drawings. The problems and embodiments described herein are examples only and do not limit the scope of the rights of this application. In particular, even if the wording of the description is different, if it is technically equivalent, the technology of this application can be applied even with different wording and does not limit the scope of the rights. Furthermore, each embodiment can be appropriately combined as long as the processing content is not contradictory.

[0013] Furthermore, the terminology and technical content used in this specification may be appropriately adapted from the terminology and technical content described in specifications and contributions of communication standards such as 3GPP. Examples of such specifications are those described in Non-Patent Documents 1 to 14.

[0014] The following describes in detail, with reference to the drawings, embodiments of the base station, terminal, and wireless communication system disclosed in this application. The following embodiments are not intended to limit the disclosed technology. Embodiment 1

[0015] Figure 1 shows an example of a wireless communication system 1 in Embodiment 1. The wireless communication system 1 includes base stations 100A and 100B, and terminals 200A, 200B, 200C, and 200D. Base station 100A forms cell C10A. Base station 100B forms cell C10B. Terminals 200A, 200B, and 200C are located within cells C10A and C10B. Terminal 200D is located within cell C10A. Base stations 100A and 100B are simply referred to as base station 100 when not distinguished. Cells C10A and C10B are simply referred to as cell C10 when not distinguished. Terminals 200A, 200B, 200C, and 200D are simply referred to as terminal 200 when not distinguished. The RRC (Radio Resource Control) status of terminal 200 is, for example, one of the following: RRC Connected, RRC Inactive, or RRC Idle. Furthermore, the wireless communication system 1 may use either TDD (Time Division Duplex) or FDD (Frequency Division Duplex) as its wireless communication method, and different methods may be applied to each cell.

[0016] The wireless communication system 1 is, for example, a wireless communication system that supports NES, in other words, a wireless communication system that supports the functions of NES. The base station 100A is, for example, a base station 100 that notifies the terminal 200 of information for camping on or accessing base station 100B that supports NES functions. Note that base station 100A is an example of a first base station.

[0017] Camping on to a cell means that terminal 200 has completed the cell selection / reselection process and selected a cell to monitor system information and paging information. Accessing a cell means that terminal 200 performs a random access procedure to the cell selected for communication. On the other hand, base station 100B is, for example, a base station 100 that supports NES functionality. Base station 100B is an example of a second base station. Terminal 200 attempts to camp on or access base station 100B based on information from base station 100A, for example. Base station 100B may also be, for example, a base station 100 that notifies terminal 200 of camping on or access information when it applies NES functionality itself. Therefore, base station 100B is also an example of a first base station. When base station 100B is applying NES functionality, terminal 200 attempts to camp on or access base station 100B based on information previously obtained from base station 100B, for example.

[0018] Furthermore, the base station 100 may be a small wireless base station such as a macro wireless base station or pico wireless base station (including micro wireless base stations, femto wireless base stations, etc.), or a wireless base station of various sizes, and may be described as a base station device, wireless communication device, communication device, transmitting device, receiving device, gNB (Node B), etc. Also, the terminal 200 may be a wireless terminal such as a terminal device, mobile phone, smartphone, PDA (Personal Digital Assistant), personal computer, vehicle, airplane, drone, or various other devices with wireless communication capabilities, or a device (sensor device, etc.) mounted on robots, AV equipment, home appliances, office equipment, vending machines, other household equipment, industrial equipment, etc., and may be described as a wireless communication device, communication device, receiving device, mobile station, UE (User Equipment), user equipment, etc.

[0019] Base station 100 is connected to the network via wired connections to the core network and network devices (higher-level devices and other base stations) which are not shown in the diagram. Alternatively, base station 100 may be connected to the network devices wirelessly instead of via wired connections. Furthermore, base station 100 transmits and receives signals with terminal 200 via cell C10.

[0020] The base station 100 may separate its wireless communication function with the terminal 200 from its digital signal processing and control functions into separate devices. In this case, the device with wireless communication functionality can be called an RRH (Remote Radio Head), and the device with digital signal processing and control functions can be called a BBU (Base Band Unit). The RRH may be installed extending from the BBU, and they may be connected by a wired connection such as an optical fiber. Alternatively, they may be connected wirelessly. Furthermore, instead of separating into RRH and BBU as described above, the base station 100 may be separated into, for example, a CU (Central Unit), a DU (Distributed Unit), and a RU (Radio Unit). The CU may include, for example, the functions of the RRC (Radio Resource Control) layer. The CU may also include, for example, the functions of the PDCP (Packet Data Convergence Protocol) layer. The CU may also include, for example, the functions of the SDAP (Service Data Adaptation Protocol) layer. The DU may include, for example, the functions of the MAC (Media Access Control) layer. Furthermore, the DU may include, for example, the functionality of the RLC (Radio Link Control) layer. The RU may include at least an RF radio circuit. The DU and RU may be integrated into a single unit.

[0021] Terminal 200 communicates with base station 100 via wireless communication.

[0022] Hereinafter, cell C10A, which is composed of base station 100A, is an example of a normal cell and will also be called normal cell A. Normal cell A is an example of a first cell. Normal cell A is, for example, a cell that does not support NES, or an NES cell (described later) to which power-saving technology is not applied. Furthermore, cell C10B, composed of base station 100B, which can transition to a state where power consumption can be reduced by applying predetermined power-saving technology (for example, a sleep state), is an example of an NES cell and will also be called NES cell B. NES cell B is an example of a second cell. NES cell B achieves power saving, for example, by stopping the transmission and reception of physical signals and physical channels other than predetermined ones in the sleep state, thereby cutting off or reducing the standby power of wireless equipment inside base station 100B. The specified physical signals and channels are, for example, the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) related to On-demand SIB1. Other specified physical signals and channels include, for example, the synchronization signals (PSS: Primary Synchronization Signal and SSS: Secondary Synchronization Signal) and PBCH (Physical Broadcast Channel) related to the Synchronization Signal / PBCH block (SSB), and the PRACH (Physical Random Access Channel) related to the UL-Wake Up Signal (UL-WUS). Furthermore, NES cell B achieves power saving by, for example, stopping the transmission of PDCCH and PDSCH related to SIB1 during sleep mode, and instead transmitting PDCCH and PDSCH related to On-demand SIB1.

[0023] Normally, cell A is an anchor cell that provides (transfers, notifies) terminal 200 with the information necessary for terminal 200 to camp on to or access NES cell B. NES cell B provides normal cell A with at least control information used to determine whether terminal 200 can camp on to or access NES cell B, control information for receiving On-demand SIB1 transmitted from NES cell B, and UL-WUS configuration information (described later) for requesting On-demand SIB1 from NES cell C10B. In the following description, unless otherwise specified, the above-mentioned SIB1 request configuration information and UL-WUS configuration information will be treated as interchangeable and synonymous configuration information. Note that SIB1 transmitted via normal cell A and On-demand SIB1 transmitted via NES cell B may be collectively referred to as SIB1. Furthermore, SIB1 and On-demand SIB1 are examples of the first system information.

[0024] Furthermore, UL-WUS configuration information may be provided, for example, from NES cell B to terminal 200.

[0025] In the example shown in Figure 1, a correspondence is illustrated where a normal cell A contains an NES cell B. However, the size and positional relationship of these two cells are merely illustrative, and other correspondences are possible. For example, the sizes of normal cell A and NES cell B may be the same, or NES cell B may be larger. A configuration in which normal cell A contains multiple NES cells B is also possible.

[0026] Furthermore, the sleep state is a state in which, for example, some of the functions related to transmission and reception of base station 100B (NES cell B) are stopped, and at the same time, power supply to internal equipment related to transmission and reception is suppressed, and base station 100B does not transmit some messages, and does not transmit or receive any or all of the corresponding physical signals or physical channels. In addition, when NES cell B is released from sleep state (the application of a predetermined power saving technology is stopped), or when the sleep state is temporarily released, it enters a non-sleep state and transitions to a cell capable of performing normal wireless communication (for example, wireless communication equivalent to that of normal cell A).

[0027] Furthermore, the NES cell may include, for example, a base station 100B that is in a sleep state, and a base station 100B that may be in a sleep state. Also, the normal cell A and the NES cell B may each be, for example, cells under the same base station 100, or cells under different base stations 100.

[0028] Terminal 200 is a communication device that wirelessly connects to base station 100A or base station 100B and transmits and receives data. Terminal 200 may also be a communication device that supports NES functions, for example. Alternatively, terminal 200 may be a communication device that does not support NES functions, for example.

[0029] In the example shown in Figure 1, the data (DL data, downlink data) transmitted from the core network (not shown) to the terminal 200 is transmitted from the core network to the base station 100, and then transmitted (transferred) from the base station 100 to the terminal 200.

[0030] Data transmitted from terminal 200 to the core network (UL data, uplink data) is transmitted from terminal 200 to base station 100, and then transmitted (transferred) from base station 100 to the core network.

[0031] Terminal 200 and base station 100 transmit and receive RRC messages (also called RRC signaling) at the Radio Resource Control (RRC) layer. Terminal 200 and base station 100 also transmit and receive MAC control elements (MAC-CE) at the Medium Access Control (MAC) layer. Furthermore, terminal 200 and base station 100 transmit and receive physical signals on physical channels at the physical layer.

[0032] RRC messages are transmitted as RRC PDUs (Protocol Data Units) and mapped to logical channels (LCHs) such as the Common Control Channel (CCCH), Dedicated Control Channel (DCCH), Paging Control Channel (PCCH), Broadcast Control Channel (BCCH), or Multicast Control Channel (MCCH).

[0033] A MAC CE is transmitted as a MAC PDU (or MAC subPDU). A MAC subPDU is equivalent to a Service Data Unit (SDU) at the MAC layer with, for example, 8 bits of header information added, and a MAC PDU contains one or more MAC subPDUs.

[0034] Next, as physical channels and physical signals related to the embodiment, there are at least the following: synchronization signal, physical broadcast channel (PBCH), physical random access channel (PRACH), PRACH preamble signal, physical downlink control channel (PDCCH), downlink control information (DCI), channel state information-reference signal (CSI-RS), physical uplink control channel (PUCCH), physical downlink shared channel (PDSCH), physical uplink shared channel (PUSCH), uplink control information (UCI), sounding reference signal (SRS), and demodulation reference signal (DMRS), but a detailed explanation is omitted.

[0035] Next, the base station 100 will be described. Figure 2 shows an example of a functional configuration block diagram of the base station 100. The base station 100 has a wireless communication unit 110, a control unit 120, a storage unit 130, and a communication unit 140.

[0036] The wireless communication unit 110 consists of a transmitting unit 111 and a receiving unit 112, and communicates wirelessly with the terminal 200. Specifically, the transmitting unit 111 transmits downlink signals to the terminal 200, such as SSB, pagging signals, random access procedure signals (e.g., RAR (Random Access Response)), RRC layer signals, downlink data signals, and downlink control signals.

[0037] The receiving unit 112 can receive uplink signals transmitted from the terminal 200, such as random access procedure signals (e.g., PRACH preamble), RRC layer signals, uplink data signals, and uplink control signals.

[0038] The control unit 120 controls the base station 100. Specifically, the control unit 120 can control the establishment of an RRC connection with the terminal 200, signal processing of signals received by the receiving unit 112, creation of a transport block (TB), and mapping of the transport block to radio resources. The control unit 120 can also control resources related to common signals and transmission / reception channels. Furthermore, the control unit 120 performs a series of controls related to On-demand SIB1 transmission. For example, the control unit 120 performs control to determine whether On-demand SIB1 transmission is necessary based on instructions from a higher layer or the reception of UL-WUS transmitted from the terminal 200. Also, for example, the control unit 120 generates a signal containing UL-WUS configuration information.

[0039] The memory unit 130 can store, for example, downlink data signals.

[0040] The communication unit 140 connects to network devices (e.g., host devices, other base station devices) via wired or wireless connections and performs communication. Data signals received by the communication unit 140 for the terminal 200 can be stored in the storage unit 130. Note that the wireless communication unit 110 and the communication unit 140 may be collectively referred to as the communication unit.

[0041] Next, the terminal 200 will be described. Figure 3 is a diagram showing an example of a functional configuration block diagram of the terminal 200. As shown in Figure 3, the terminal 200 comprises a communication unit 210, a control unit 220, and a storage unit 230. Each of these components is connected in such a way that signals and data can be input and output in one direction or bidirectionally. The communication unit 210 can be described separately as a transmitting unit 211 and a receiving unit 212.

[0042] The transmitting unit 211 transmits data signals and control signals via wireless communication using an antenna. Note that the antenna may be common for both transmission and reception. The transmitting unit 211 transmits, for example, uplink signals such as random access procedure signals, RRC layer signals, uplink data signals, and uplink control signals.

[0043] The receiving unit 212 receives downlink signals transmitted from the base station 100, such as SSB, Paging signals, random access procedure signals, downlink data signals, and downlink control signals. Further, the received signals may include, for example, reference signals used for channel estimation and demodulation. Also, the receiving unit 212 can receive measurement signals transmitted from the base station 100 and measure the signals.

[0044] The control unit 220 controls the terminal 200. Specifically, the control unit 220 can control the establishment of an RRC connection with the base station 100, signal processing of the signals received by the receiving unit 212, creation of a transmission block (TB), mapping of the transmission block to radio resources, etc. Also, the control unit 220 can control the measurement of measurement signals in the receiving unit 212. Further, the control unit 220 can perform a series of controls related to on-demand SIB1 acquisition. For example, the control unit 220 executes control to determine whether the cell is a NES cell based on the UL-WUS setting. Also, the control unit 220 executes control to determine the reception method of on-demand SIB1. Also, the control unit 220 executes control to determine the necessity of UL-WUS transmission.

[0045] The storage unit 230 can store, for example, uplink data signals. Also, the storage unit 230 can store configuration information (or setting information) related to wireless communication (e.g., UL-WUS setting information) transmitted from the base station 100.

[0046] Here, On-demand SIB1 will be described. On-demand SIB1 is one of the power-saving technologies applied to the base station 100. It is a method that stops the periodic transmission of SIB1, which is one of the notification information transmitted periodically, and transmits it as appropriate based on a request from the terminal 200. The content included in On-demand SIB1 includes at least the setting information (radio connection information (cell common resource information, cell selection criterion information, access control information, etc.)) notified by the conventional SIB1. Furthermore, it may also include UL-WUS setting information indicating the transmission setting of UL-WUS, which is a signal for requesting On-demand SIB1.

[0047] The base station 100B may be configured to perform on-demand transmission similarly for system information (SIB2, SIB3,...) other than On-demand SIB1. Note that the access control information may be referred to by similar terms such as access restriction information, access control information, or access prohibition information. Similarly, On-demand SIB1 may be referred to by similar terms such as OD-SIB1, Non-periodic SIB1, etc., or it may be referred to as SIB1 as before, as long as it can be determined from the context that it is transmitted on demand.

[0048] The terminal 200 detects and acquires the SSB of the base station 100B in order to receive the On-demand SIB1 of the base station 100B (NES cell B), and adjusts the downlink synchronization using the SSB. The SSB includes a synchronization signal (Synchronization Signal) and a physical broadcast channel (PBCH: Physical Broadcast Channel). Also, the synchronization signal is composed of a primary synchronization signal (PSS: Primary Synchronization Signal) and a secondary synchronization signal (SSS: Secondary Synchronization Signal).

[0049] Next, terminal 200 obtains, for example, PDCCH transmission resource information (pdcch-ConfigSIB) and SSB subcarrier offset information (ssb-subcarrierOffset) from UL-WUS configuration information transmitted by base station 100A (normal cell A). PDCCH transmission resource information is information that specifies the area in which a PDCCH that instructs scheduling information for a PDCCH transmitting On-demand SIB1 (or SIB1) may be transmitted. PDCCH transmission resource information includes information that specifies the PDCCH resource in the search space area (SearchSpaceZero) and information that specifies the PDCCH resource in the CORESET (Control Resource Set) area (ControlResourceSetZero). SearchSpaceZero may also be called a common search area or type zero search space. The ControlResourceSetZero may also be referred to as Control Resource Set Zero or CORESET0. SSB subcarrier offset information is a parameter that indicates the frequency offset of the SSB transmission position in subcarrier units. The base station 100B may also be configured to indicate that the cell is an NES cell B (i.e., an SIB1 untransmitted cell) rather than the SSB frequency offset by setting a predetermined value in the SSB subcarrier offset information included in the MIB (Master Information Block) transmitted in SSB (PBCH). The base station 100B does not have to include PDCCH transmission resource information in the MIB. The terminal 200 may also obtain, for example, PDCCH transmission resource information (pdcch-ConfigSIB) and SSB subcarrier offset information (ssb-subcarrierOffset) obtained from the MIB transmitted in SSB (PBCH) of the base station 100B (NES cell B).

[0050] Terminal 200 monitors the PDCCH that schedules SIB1 based on the acquired transmission resource information and acquires the PDSCH (On-demand SIB1) indicated by the downlink control information contained in the detected PDCCH. Base station 100 scrambles the PDCCH that schedules SIB1 with the network identification information (SI-RNTI: System Information-Radio Network Temporary Identifier) ​​of SIB1, which is composed of a known bit sequence, and transmits it. In the area where terminal 200 monitors the PDCCH, it may attempt to reverse scramble the PDCCH using SI-RNTI, and if the PDCCH is decoded correctly, it may then acquire the On-demand SIB1 based on DCI. Here, MIB and SIB1 (On-demand SIB1) are essential system information, respectively.

[0051] Furthermore, terminal 200 calculates cell quality (received quality) for each cell by measuring SSB or channel status information reference signal (CSI-RS). Cell quality can be expressed using one of the following: RSRP (Reference Signal Received power), RSRQ (Reference Signal Received Quality), RSSI (Received Signal Strength Indicator), SINR (Signal to Interference plus Noise Ratio), or path loss.

[0052] The UL-WUS configuration information is described below. The UL-WUS configuration information includes some or all of the following information: cell information that identifies the cell transmitting UL-WUS (physical cell identifier (PCI), downlink frequency information, etc.), information related to UL-WUS transmission (PRACH resource information, SSB received power threshold, TDD UL / DL slot setting, uplink frequency, etc.), information related to SIB1 reception (SSB subcarrier offset information, PDCCH transmission resource information, etc.), and information related to PRACH response reception (RAR) (RAR monitoring window length (ra-ResponseWindow), etc.). Furthermore, it may also include cell selection criteria information (RSRP threshold, cell-specific offset value, etc.). The terminal 200 may determine, based on the cell information, whether the cell belonging to the base station 100 is a normal cell A or an NES cell B. Furthermore, base station 100B may include SSB subcarrier offset information (ssb-subcarrierOffset) and PDCCH transmission resource information (pdcch-ConfigSIB) used for receiving SIB1 within NES cell B in the corresponding UL-WUS configuration information instead of MIB. Also, base station 100B may include the monitoring window length of On-demand SIB1 used for receiving On-demand SIB1 in the UL-WUS configuration information.

[0053] Next, an example of processing in the wireless communication system 1 in Embodiment 1 will be described using Figure 4. Figure 4 is a diagram showing an example of a sequence diagram of the wireless communication system in Embodiment 1.

[0054] Figure 4 will be explained. The transmitting unit 111 of the base station 100A, which forms cell C10A (normally cell A), transmits a first signal (step S10). The receiving unit 212 of the terminal 200 receives the first signal (step S10). The first signal includes, for example, UL-WUS configuration information for the terminal 200 to request On-demand SIB1 from the base station 100B, which will be described later. The UL-WUS configuration information may include, for example, first information, which is information indicating the time offset used for receiving On-demand SIB1. The UL-WUS configuration information may also include, for example, second information, which is the reference time used for receiving On-demand SIB1. The first signal is, for example, a signal of the RRC layer. The RRC layer signal includes, for example, SIB (System Information Block) information. Furthermore, the UL-WUS configuration information is an example of the first configuration information, and UL-WUS configuration information may be referred to as the first configuration information hereafter. Also, On-demand SIB1 is an example of the fourth signal. In addition, the control unit 120 of the base station 100A controls the terminal 200 to determine the start timing of the monitoring window for On-demand SIB1, which will be described later, by transmitting the first signal including the UL-WUS configuration information.

[0055] The information indicating the time offset may be transmitted in the first signal, or in a signal different from the first signal. Alternatively, the information indicating the time offset may be predetermined and stored in the memory unit 130 of the base station 100 and the memory unit 230 of the terminal 200. The information indicating the time offset is an example of the first information. Furthermore, the first information may be part of the first setting information. When storing the information indicating the time offset in the memory units 130 and 230, specific values ​​may be defined in the specifications.

[0056] Furthermore, the reference time information may be included in the first signal and transmitted, or it may be included in a signal different from the first signal and transmitted. Alternatively, the reference time information may be predetermined and stored in the memory unit 130 of the base station 100 and the memory unit 230 of the terminal 200. The reference time information is an example of the second information. Furthermore, the second information may be part of the first setting information.

[0057] The first signal may also be transmitted from the transmitting unit 111 of the base station 100B that forms cell C10B, which is an NES cell (step S10). The receiving unit 212 of the terminal 200 may also receive the first signal from the base station 100B (step S10).

[0058] The control unit 220 of the terminal 200 determines whether to camp on to or access cell C10B, or neither, based on the first configuration information and the cell quality measured based on the SSB transmitted from the base station 100B that forms cell C10B, which is an NES cell. The control unit 220 of the terminal 200 may also perform decisions on cell selection or cell re-selection, whether cell C10B is an NES cell, and how to receive On-demand SIB1.

[0059] The control unit 220 of terminal 200, for example, when it determines to perform camp-on to NES cell B, controls the transmission of a second signal according to the transmission resource information (e.g., PRACH resource information) of the second signal included in the first configuration information. The transmission unit 211 of terminal 200 then transmits the second signal to the base station 100B forming cell C10B (step 20). The receiving unit 112 of base station 100B also receives the second signal (step 20). The second signal is, for example, a UL-WUS signal for requesting On-demand SIB1. Specifically, the second signal is, for example, a PRACH preamble signal transmitted via the PRACH resource. The PRACH preamble signal may also be referred to as message 1.

[0060] The transmitting unit 111 of the base station 100B transmits a third signal (step 30). The receiving unit 212 of the terminal 200 receives the third signal (step 30). The third signal is, for example, a response signal to the second signal. Specifically, the third signal is, for example, a RAR transmitted via the PDSCH resource. The RAR may also be referred to as message 2. The RAR includes an identifier (RAPID: Random Access Preamble Identifier) ​​for identifying the second signal transmitted by the terminal 200. The RAR may also include information (Acknowledgement) confirming the transmission of On-demand SIB1. The RAR may also include first information which is information indicating a time offset. The RAR may also include first information which is information which is a reference time. In addition to the RAR transmitted via the PDSCH resource, the third signal may also include a DCI transmitted via the PDCCH resource. The DCI schedules the RAR's PDSCH resources. The control unit 120 of the base station 100B controls the transmission of a third signal when it determines, for example, to transmit On-demand SIB1 or to temporarily wake the sleep state.

[0061] To receive the RAR, the control unit 220 of terminal 200 starts the RAR monitoring window (ra-ResponseWindow) during the first PDCCH occasion after transmitting the second signal. The PDCCH occasion is the time specified by the base station 100 for terminal 200 to receive the DCI transmitted in PDCCH. The control unit 220 of terminal 200 sets the duration of the RAR monitoring window according to the RAR monitoring window length included in the first configuration information.

[0062] The receiving unit 212 of terminal 200 monitors the PDCCH that schedules the RAR, for example, while the RAR monitoring window is operating, that is, before the end of the RAR monitoring window period. Specifically, the receiving unit 212 of terminal 200 attempts to reverse scramble the PDCCH using identification information called RA-RNTI (Random Access-Radio Network Temporary Identifier) ​​in the area where the PDCCH that schedules the RAR may be transmitted. Some or all of the information about the transmission resources of the PDCCH (DCI) that schedules the RAR may be included in the first configuration information. If the information about the transmission resources of the PDCCH (DCI) that schedules the RAR is not included in the first configuration information, the PDCCH resource information for the RAR follows the PDCCH resource information of On-demand SIB1. If the PDCCH is decoded correctly, the receiving unit 212 of terminal 200 then receives the RAR based on the DCI. The control unit 220 of terminal 200 determines that the RAR has been successfully received if the received RAR contains the identifier (RAPID) of the PRACH preamble transmitted by terminal 200. Furthermore, if the RAR has been successfully received, the control unit 220 of terminal 200 may, for example, stop the RAR monitoring window (ra-ResponseWindow) before the end of the RAR monitoring window period.

[0063] If the RAR is successfully received, or if the successfully received RAR includes an authorization for On-demand SIB1 transmission, the control unit 220 of the terminal 200 performs a first process to receive On-demand SIB1 (step 40). The first process starts the monitoring window for On-demand SIB1 from a first time, according to information that includes some or all of the reference time (second information) and information indicating a time offset (first information). The first process may also include setting the duration of the monitoring window for On-demand SIB1 according to the monitoring window length for On-demand SIB1 included in the first setting information.

[0064] Furthermore, the control unit 120 of the base station 100B performs a second process for transmitting On-demand SIB1 (step 50). The second process starts the monitoring window for On-demand SIB1 from a first time, according to information that includes some or all of the reference time (second information) and information indicating a time offset (first information). The second process may also include a process to set the duration of the monitoring window for On-demand SIB1 according to the monitoring window duration for On-demand SIB1 included in the first setting information.

[0065] The transmitting unit 111 of the base station 100B transmits a fourth signal (step 60). The receiving unit 212 of the terminal 200 receives the fourth signal (step 60). The fourth signal is On-demand SIB1. The fourth signal is, for example, On-demand SIB1 via a PDSCH resource. The fourth signal includes, for example, a DCI transmitted via a PDCCH resource. The DCI schedules the PDSCH resource that transmits On-demand SIB1.

[0066] To receive On-demand SIB1, the receiving unit 212 of terminal 200 monitors the PDCCH that schedules On-demand SIB1 while the monitoring window for On-demand SIB1 is operating, that is, before the period of the monitoring window for On-demand SIB1 ends. Specifically, the receiving unit 212 of terminal 200 attempts to reverse scramble the PDCCH using SI-RNTI in the region where the PDCCH that schedules On-demand SIB1 may be transmitted, in accordance with the information regarding SIB1 reception included in the first configuration information (e.g., PDCCH transmission resource information). The transmission resource information of the PDCCH (DCI) that schedules On-demand SIB1 may also be included, for example, in the MIB associated with cell C10B. If the PDCCH is decoded correctly, the receiving unit 212 of terminal 200 then receives the On-demand SIB1 based on the DCI. The control unit 220 of terminal 200 may, for example, stop the monitoring window for the On-demand SIB1 before the end of the monitoring window period if it has successfully received the On-demand SIB1. The receiving unit 212 of terminal 200 may, for example, stop monitoring the PDCCH that schedules the On-demand SIB1 if the control unit 220 of terminal 200 stops the monitoring window for the On-demand SIB1.

[0067] Next, the first time in Embodiment 1 will be explained using Figure 5. Figure 5 is a diagram showing an example of the start timing of the monitoring window of On-demand SIB1.

[0068] Figure 5(A) shows an example of the first time. For example, the time point indicating the reference time is defined as reference time T1, and the time period indicating the time offset is defined as time offset t1. Terminal 200 starts the monitoring window of On-demand SIB1 when, for example, time T2 occurs after time offset t1 has elapsed from reference time T1. Therefore, terminal 200 starts the monitoring window of On-demand SIB1 at time T2, which is time t1 after reference time T1 has elapsed.

[0069] Figure 5(B) shows an example of a first time. For example, a time point indicating a reference time is defined as reference time T1, and a time period indicating a time offset is defined as time offset t1. Terminal 200 starts the monitoring window of On-demand SIB1, for example, after time offset t1 has elapsed from reference time T1, setting a predetermined time T3 as the first time. The predetermined time T3 is determined, for example, based on information regarding the monitoring window of On-demand SIB1. Information regarding the monitoring window of On-demand SIB1 includes, for example, at least one of the following: period information, time offset information within the period, etc. Information regarding the monitoring window of On-demand SIB1 may be transmitted, for example, included in the first signal, or transmitted included in a signal different from the first signal. Furthermore, information regarding the monitoring window of On-demand SIB1 may be predetermined and stored in the memory unit 130 of the base station 100 and the memory unit 230 of the terminal 200. The predetermined time T3 is, for example, the start time of the first symbol in the first PDCCH occasion of On-demand SIB1 after a time offset t1 has elapsed from the reference time T1. The PDCCH occasion of On-demand SIB1 is the time specified by the base station 100 for the terminal 200 to receive the DCI transmitted in PDCCH in order to schedule On-demand SIB1. For example, if the time period from reference time T1 to time T3 is t2, the terminal 200 starts the time window of On-demand SIB1 after time t2 has elapsed from reference time T1. Note that the time window is an example of a monitoring window or monitoring time window. Furthermore, the time window for On-demand SIB1 may also be described as, for example, SIB1 monitoring window, SIB1 monitoring time window, On-demand SIB1 monitoring window, or On-demand SIB1 monitoring time window.

[0070] The first PDCCH occasion of On-demand SIB1 may be, for example, the PDCCH occasion of On-demand SIB1 corresponding to the smallest candidate SSB index, i.e., candidate SSB index 0. Terminal 200 obtains candidate SSB index information (ssb-PositionsInBurst) from, for example, first configuration information transmitted by base station 100. The candidate SSB index information is represented, for example, in the form of a bitmap, where the first bit corresponds to candidate SSB index 0 and the next bit corresponds to candidate SSB index 1. Terminal 200 obtains information regarding the PDCCH occasions of On-demand SIB1 corresponding to each candidate SSB index, including candidate SSB index 0, from, for example, first configuration information transmitted by base station 100 or MIB transmitted by base station 100B. Information regarding the PDCCH occasions of On-demand SIB1 corresponding to each candidate SSB index, including candidate SSB index 0, is included, for example, in the PDCCH transmission resource information (pdcch-ConfigSIB, SearchSpaceZero) of On-demand SIB1.

[0071] Furthermore, the first On-demand SIB1 PDCCH occasion may be, for example, the PDCCH occasion of the on-demand On-demand SIB1 corresponding to the first SSB index actually transmitted. Terminal 200 obtains information on the actually transmitted SSB index from, for example, the first configuration information transmitted by base station 100. Information on the actually transmitted SSB index is included, for example, in candidate SSB index information (ssb-PositionsInBurst). The actually transmitted SSB index is, for example, the candidate SSB index corresponding to the bit with a value of 1 in the bitmap of ssb-PositionsInBurst.

[0072] Furthermore, the first On-demand SIB1 PDCCH occasion may be, for example, the On-demand SIB1 PDCCH occasion corresponding to the actually transmitted SSB index associated with the UL-WUS signal (e.g., the second signal) transmitted by terminal 200. Terminal 200 obtains the associated information (ssb-perRACH-Occasion) of the UL-WUS signal and the SSB index from, for example, the first configuration information transmitted by base station 100.

[0073] In the examples of Figures 5(A) and 5(B), the time offset t1 is less than or equal to the time difference t2 from the reference time T1 to the first time. Therefore, the time offset t1 represents the minimum time difference from the reference time T1 to the first time. The terminal 200 does not expect, for example, that the monitoring window of On-demand SIB1 to start before the time point after the time offset t1 has elapsed from the reference time T1.

[0074] Now, let's explain the reference time.

[0075] The control unit 220 of terminal 200 controls the On-demand SIB1 to start its time window from a first time, according to the reference time, and to receive the On-demand SIB1. The reference time may be, for example, the start time or end time of the RAR monitoring window.

[0076] The start time of the RAR monitoring window may be, for example, the time when the first symbol of the first RAR PDCCH occasion begins after terminal 200 has transmitted the UL-WUS signal (e.g., the second signal). Alternatively, the start time of the RAR monitoring window may be, for example, the time when the slot in which the first RAR PDCCH occasion exists after terminal 200 has transmitted the UL-WUS signal begins.

[0077] Furthermore, if terminal 200 successfully receives RAR (third signal), it may or may not stop the RAR monitoring window. Also, even if the RAR monitoring window is not stopped after successfully receiving RAR, terminal 200 may stop monitoring the PDCCH that schedules RAR. For example, let time T4 be the time when terminal 200 stops the RAR monitoring window, and time T5 be the time point at which the period of the RAR monitoring window, which is set according to the RAR monitoring window length included in the first configuration information, ends. If the reference time is the end time of the RAR monitoring window, terminal 200 and base station 100B may, for example, set time T4 as the end time of the RAR monitoring window. Also, terminal 200 and base station 100B may, for example, set time T5 as the end time of the RAR monitoring window.

[0078] Now, let's explain the time offset. The time offset represents the minimum time difference from the reference time to the start of the monitoring window of On-demand SIB1 (the first time).

[0079] The time offset may be set to a predetermined value, for example. For example, base station 100 sets a predetermined value as a common time offset for terminals 200 located in an NES cell (e.g., cell C10B). If the reference time is the end time of the RAR monitoring window, the predetermined value is, for example, the RAR processing time or 0. The RAR processing time is, for example, the PDSCH (transmit block) processing time and depends on the terminal processing capacity and the number of DMRS in the PDSCH. Alternatively, the RAR processing time may be determined according to the terminal processing capacity and the number of PDSCH DMRS (e.g., there are two DMRS in one PDSCH). The RAR processing time may also be expressed, for example, as the length of time over a predetermined number of symbols or slots. The length of time over a predetermined number of symbols or slots may also be determined, for example, based on the subcarrier spacing (SCS) of the PDSCH transmitting the RAR or the PDCCH sizing the RAR. Furthermore, if the subcarrier interval of the PDSCH transmitting the RAR differs from the subcarrier interval of the PDCCH sizing the RAR, the RAR processing time may be determined based on the smaller subcarrier interval. The subcarrier interval may also be included in the first configuration information or the MIB transmitted via the NES cell (e.g., cell C10BB). If multiple subcarrier intervals are set in the first configuration information or the MIB transmitted via the NES cell, the RAR processing time may be determined based on the smallest subcarrier interval.

[0080] Furthermore, if the time offset is set to a predetermined value, the start time of the RAR monitoring window may be used as the reference time. When the reference time is the start time of the RAR monitoring window, the predetermined value is, for example, the sum of the duration of the RAR monitoring window (ra-ResponseWindow) and the RAR processing time, the duration of the RAR monitoring window, and the sum of the time from the start time of the RAR monitoring window to the last PDCCH occasion within the RAR monitoring window and the RAR processing time. The RAR processing time is the same as when the reference time is the end time of the RAR monitoring window, so its explanation is omitted.

[0081] Here, an example of a predetermined value set as a time offset for terminal 200 will be explained using Figure 6. Figure 6 is a diagram showing an example of a RAR monitoring window. Two examples of predetermined values ​​will be explained.

[0082] The first example will be explained using Figure 6(A). Figure 6(A) is a diagram showing an example of a RAR monitoring window. For example, the RAR monitoring window is from the first symbol to the last symbol of slot n, and its duration is 1 slot. In section S1 within the RAR monitoring window, terminal 200 receives a PDCCH (S1) that schedules the RAR, and in section S2 within the RAR monitoring window, terminal 200 receives a PDSCH (S2) that transmits the RAR. In the example in Figure 6(A), the duration of section S1 is 2 symbols, and the duration of section S2 is 12 symbols. The durations of sections S1 and S2 combined are 1 slot. After receiving the RAR, terminal 200 processes the RAR. Therefore, terminal 200 processes the RAR after the RAR monitoring window has finished. After processing the RAR, terminal 200 starts the On-demand SIB1 time window and becomes able to receive On-demand SIB1. Therefore, in the example in Figure 6(A), if the reference time is the end time of the RAR monitoring window, the time offset value is set to the RAR processing time. Also, if the reference time is the start time of the RAR monitoring window, the time offset value is set to the sum of the RAR monitoring window period (ra-ResponseWindow) and the RAR processing time, or the sum of the time from the start time of the RAR monitoring window to the last PDCCH occasion within the RAR monitoring window and the RAR processing time.

[0083] The first example will be explained using Figure 6(B). Figure 6(B) is a diagram showing an example of a RAR monitoring window. For example, the RAR monitoring window is from the first symbol to the last symbol of slot n, and its duration is, for example, 1 slot. Terminal 200 receives a PDCCH for scheduling the RAR in section S3 within the RAR monitoring window, and receives a PDSCH for transmitting the RAR in section S4 within the RAR monitoring window. Note that Figure 6(B) shows an example where the duration of section S3 is 2 symbols and the duration of section S4 is 5 symbols. Terminal 200 can complete the RAR processing before the RAR monitoring window ends. Therefore, in the example in Figure 6(B), if the reference time is the end time of the RAR monitoring window, the value of the time offset is 0. Also, if the reference time is the start time of the RAR monitoring window, the time offset is the duration of the RAR monitoring window (ra-ResponseWindow).

[0084] Furthermore, the time offset may be set to any arbitrary value, for example. For instance, base station 100 can instruct different terminals 200 located in an NES cell (e.g., cell C10B) to use different time offsets of any arbitrary value. These different terminals 200 are those that have transmitted different UL-WUS signals to the NES cell (e.g., cell C10B). The time offset may also be expressed in relative time or absolute time.

[0085] When expressing a time offset in absolute time, the time offset may be expressed as, for example, seconds, milliseconds, or microseconds.

[0086] When the time offset is expressed in relative time, the time offset may also be expressed as, for example, the offset of the SFN (System Frame Number), the number of frames, the number of symbols, the number of slots, or the number of repetition periods of On-demand SIB1. The SFN offset is, for example, the difference in frame numbers from the frame number of the reference time to the frame number of the first time. The repetition period of On-demand SIB1 may use a default value of, for example, 20 milliseconds. Alternatively, the repetition period of On-demand SIB1 may be included in, for example, the first configuration information or transmitted in the MIB transmitted via the NES cell.

[0087] Furthermore, when expressing the time offset in terms of relative time, the time offset can be expressed as a numerical value calculated using, for example, the following equation (1): (Equation 1) Time offset = FLOOR(x / y)

[0088] In Equation 1, x is the absolute time of the time offset. The relative time of the time offset is expressed as a number obtained by truncating the result of dividing this absolute time x by y using the FLOOR function. Hereinafter, y is, for example, the repetition period of On-demand SIB1. For y, a default value of, for example, 20 milliseconds may be used. Alternatively, y may be included in the MIB transmitted via, for example, the first configuration information or the NES cell.

[0089] Here, we will explain the time offset expressed in relative time using Figure 7. Figure 7 is a diagram showing an example in which different time offsets are instructed for different terminals 200. In Figure 7, for example, time T1 is the reference time, and times T6, T7, and T8 are the start timings of the On-demand SIB1 time window for terminals 200A, 200B, and 200C, respectively. Therefore, terminals 200A, 200B, and 200C use their respective start timings as the first time, start the On-demand SIB1 time window, and receive the On-demand SIB1.

[0090] Therefore, for example, terminal 200A starts the On-demand SIB1 time window at time T6 after time period t3 has elapsed. Similarly, for example, terminal 200B starts the On-demand SIB1 time window at time T7 after time period t4 has elapsed. And terminal 200C starts the On-demand SIB1 time window at time T8 after time period t5 has elapsed. Thus, t3, t4, and t5 are time offsets for terminals 200A, 200B, and 200C to determine the first time, respectively. These time offsets may be expressed in absolute time. For example, they may be directly expressed as t3 milliseconds, t4 milliseconds, and t5 milliseconds. Alternatively, these time offsets may be expressed in relative time. For example, if t3 milliseconds, t4 milliseconds, and t5 milliseconds are 2 milliseconds, 22 milliseconds, and 42 milliseconds, respectively, then using equation (1), x will be 2 milliseconds, 22 milliseconds, and 42 milliseconds, respectively. If y is the default repetition period of On-demand SIB1 at 20 ms, the expressed values ​​for t3, t4, and t5 will be 0, 1, and 2, respectively. Also, if expressed as an SFN offset, the expressed values ​​for t3, t4, and t5 will be 0, 2, and 4, respectively. Furthermore, if expressed as the number of slots, and the time length of one slot is 1 ms (subcarrier interval is 15 kHz), the expressed values ​​for t3, t4, and t5 will be 2, 22, and 42, respectively. By using equation (1), the expressed values ​​can be made smaller. Therefore, by using equation (1), the range of time offsets that can be indicated with the same number of bits can be widened.

[0091] Next, we will explain how to specify the time offset.

[0092] The time offset may be indicated by the first information. Base station 100 may, for example, include the first information in the first signal and transmit it to terminal 200. Base station 100B (second base station) may, for example, include the first information in the third signal and transmit it to terminal 200. Base station 100B may, for example, include the first information in a signal different from the first signal and the third signal and transmit it to terminal 200. The first information may, for example, be predetermined. The first information may, for example, include one or more time offset values.

[0093] Furthermore, the first information may be, for example, information indicating one of several predetermined values. For example, if a parameter indicating a time offset is set or indicated by the value "TRUE", and the reference time is the end time of the RAR monitoring window, terminal 200 uses the RAR processing time as the time offset. Also, for example, if the reference time is the start time of the RAR monitoring window, terminal 200 uses the RAR processing time as the sum of the RAR monitoring window period (ra-ResponseWindow) and the RAR processing time, or the sum of the time from the start time of the RAR monitoring window to the last PDCCH occasion within the RAR monitoring window and the RAR processing time. Furthermore, if a parameter indicating a time offset is not set or indicated by the value "FALSE", and the reference time is the end time of the RAR monitoring window, terminal 200 uses 0 as the time offset. Furthermore, for example, if the reference time is the start time of the RAR monitoring window, terminal 200 uses the RAR processing time as the duration of the RAR monitoring window (ra-ResponseWindow).

[0094] Furthermore, the first information may, for example, be information indicating one of several time offsets (or the values ​​of several time offsets). Note that the multiple time offsets may be transmitted, for example, included in the first signal, or included in a signal different from the first signal.

[0095] Furthermore, if the first information is included in the third signal, it may be included in the PDCCH that schedules the RAR, or it may be included in the RAR itself.

[0096] Furthermore, if the first information is included in the RAR, an existing RAR MAC PDU or MAC SubPDU format may be used, or a new MAC PDU or MAC SubPDU format may be defined. Note that a MAC PDU consists of one or more MAC SubPDUs and padding as necessary.

[0097] When using the RAR MAC SubPDU format, for example, a MAC SubPDU format that includes a Backoff Indicator (BI) is used. The case where the MAC SubPDU format that includes a backoff indicator as information included in the third signal is used will be explained with reference to Figure 8. Figure 8 is a diagram showing an example of the MAC SubPDU format. In the example shown in Figure 8, the MAC SubPDU includes one MAC subheader, and the MAC subheader consists of multiple header fields. Here, the E field ("E" in the figure) is, for example, an extension field, and one bit is used to indicate whether the MAC SubPDU containing this MAC subheader is the last MAC SubPDU in the MAC PDU. If the E field is set to 0, for example, it indicates that the MAC SubPDU containing this MAC subheader is the last MAC SubPDU in the MAC PDU. Furthermore, if E is set to 1, for example, it indicates that the MAC SubPDU containing this MAC subheader is not the last MAC SubPDU in the MAC PDU. The T field ("T" in the figure) is, for example, a Type field, and uses one bit to indicate whether this MAC subheader contains a RAPID or backoff instruction. The R1 field ("R1" in the figure) is, for example, another Type field, and indicates whether this MAC subheader contains a backoff instruction (BI field) or information indicating a time offset (TO1 field). If the R1 field is set to 0, for example, this MAC subheader contains a backoff instruction. Also, if the R1 field is set to 1, for example, this MAC subheader contains information indicating a time offset. The R2 field ("R2" in the figure) is, for example, a reserved bit, and is set to 0. The BI field (indicated as "BI" in the diagram) contains information indicating that On-demand SIB1 will not be transmitted and the backoff time. The TO1 field (indicated as "TO1" in the diagram) contains information indicating the time offset.The TO1 field also contains information indicating authorization for the transmission of On-Demand SIB1 and a time offset. The TO1 field may use multiple bits, for example. Alternatively, the TO1 field may use four bits, for example. Furthermore, for example, the MAC subheader may not have a hold bit, and the TO1 field may use five bits.

[0098] Furthermore, the base station 100B generates a MAC SubPDU as a response signal for each different PRACH preamble signal it receives. The transmitted PRACH preamble signal may be a UL-WUS signal (second signal) or a random access signal different from the UL-WUS signal (second signal). For example, the base station 100B may combine multiple MAC SubPDUs into a single MAC PDU and transmit them in response to the received UL-WUS signal and a random access signal different from the UL-WUS signal.

[0099] Furthermore, for example, if base station 100B transmits multiple MAC SubPDUs generated for the received UL-WUS signal and random access signals different from the UL-WUS signal as a single MAC PDU, terminal 200 that does not support NES functionality may confuse the MAC SubPDU containing time offset information (MAC SubPDU containing time offset information) with the MAC SubPDU containing backoff instructions (MAC SubPDU containing backoff instructions). To avoid this confusion, base station 100B may, for example, add a MAC subheader containing the RAPID of the received UL-WUS signal before the MAC SubPDU containing time offset information. That is, base station 100B places the MAC subheader containing time offset information after the MAC subheader containing the RAPID of the received UL-WUS signal and transmits it as a single MAC Sub-PDU.

[0100] Furthermore, when base station 100B transmits a MAC SubPDU for backoff instructions and a MAC SubPDU for time offset information together in a single MAC PDU, the MAC SubPDU for backoff instructions may be placed at the beginning of the MAC PDU to avoid confusion. Here, using Figure 9, an example in which a single MAC PDU contains multiple MAC SubPDUs will be explained. Figure 9 is an example of a MAC PDU containing multiple MAC SubPDUs. In Figure 9, the MAC PDU transmitted by base station 100B consists of two MAC SubPDUs, MAC SubPDU1 and MAC SubPDU2, and padding. MAC SubPD1, placed at the beginning, is a MAC SubPDU for backoff instructions for terminal 200A that does not support NES functionality. MAC SubPDU2 is a MAC SubPDU for NES-enabled terminal 200B that transmitted the UL-WUS signal, and includes a subheader containing information indicating a time offset.

[0101] Furthermore, to avoid confusion, for example, base station 100B may set the transmission resources for UL-WUS signals and the transmission resources for random access signals different from UL-WUS signals to different PRACH resources. Also, for example, base station 100B may transmit MAC SubPDUs for UL-WUS signals and MAC SubPDUs for random access signals different from UL-WUS signals separately. Also, for example, base station 100 may set up a dedicated RA-RNTI for transmitting MAC PDUs that include MAC Sub-PDUs for UL-WUS signals.

[0102] Here, we will explain the case where the new MAC PDU or MAC SubPDU format is used, using Figure 10. Figure 11 is a diagram showing an example of MAC SubPDU.

[0103] Figure 10(A) shows a first example of a new MAC SubPDU format. The MAC SubPDU format shown in Figure 10(A) is referred to as Format 1. In the example shown in Figure 10(A), the MAC SubPDU consists of one MAC subheader and a MAC payload containing information indicating the time offset. The MAC subheader consists of an E field, a T field, and a RAPID field to indicate the RAPID of the transmitted UL-WUS signal. The E field, T field, and RAPID are the same as those in existing MAC SubPDUs, so their explanation is omitted. The MAC payload consists of a TO2 field (indicated as "TO2" in the figure). The TO2 field contains information indicating the time offset. The TO2 field may use, for example, multiple bits. Alternatively, the TO2 field may use, for example, eight bits or a number of bits that is a multiple of eight. Furthermore, the TO2 field is, for example, the same size as existing RAR payloads.

[0104] Figure 10(B) shows a second example of the new MAC SubPDU format. The MAC SubPDU format shown in Figure 10(B) may also be referred to as Format 2. In the example shown in Figure 10(B), the MAC payload consists of the E1 field and the TO3 field (in the figure, "TO3"). For example, multiple bits are used. The E1 field uses, for example, one bit to indicate whether this MAC SubPDU is the last MAC SubPDU in the MAC PDU. If the E1 field is set to 0, for example, it indicates that this MAC SubPDU is the last MAC SubPDU in the MAC PDU. If the E1 field is set to 1, for example, it indicates that this MAC SubPDU is not the last MAC SubPDU in the MAC PDU. The TO3 field is information indicating the time offset. The TO3 field uses, for example, multiple bits. Furthermore, the TO3 field uses, for example, seven bits.

[0105] Furthermore, for example, if base station 100B transmits multiple MAC SubPDUs generated for a received UL-WUS signal and a random access signal different from the UL-WUS signal, combined into a single MAC PDU, terminals that do not support NES functionality will encounter a problem in that they do not know where the next MAC SubPDU begins because the size of the new format MAC SubPDU (i.e., a MAC SubPDU containing information indicating the time offset) is unknown. To avoid this, base station 100B places the new format MAC SubPDU containing the time offset information after the existing format MAC SubPDU. Here, an example of a MAC PDU containing multiple MAC SubPDUs will be explained using Figure 11. Figure 11 is a diagram showing an example of a MAC PDU containing multiple MAC SubPDUs.

[0106] Figure 11(A) shows an example of a MAC PDU including MAC SubPDUs in existing formats and MAC SubPDUs in new formats. For example, a MAC PDU transmitted by base station 100B consists of three MAC SubPDUs and padding. The first MAC SubPDU (i.e., MAC SubPDU1) is a MAC SubDDU in existing formats for terminal 200A, which does not support NES functionality. The two MAC SubPDUs placed after MAC SubPDU1 (i.e., MAC SubPDU2 and MAC SubPDU3) are MAC SubDDUs in format 1 for terminals 200B and 200C, which transmit UL-WUS signals and support NES functionality, respectively. Furthermore, base station 100B sets the value of the E field of the MAC SubPDU placed before the MAC SubPDU of format 1 (i.e., MAC SubPDU1) to 0. As a result, terminal 200A, which does not support NES functionality, recognizes MAC SubPDU1 as the last MAC SubPDU, determines that everything after MAC SubPDU1 is padding, and does not read it. On the other hand, terminals 200B and 200C, which support NES functionality, continue to read MAC SubPDU2 and MAC SubPDU3, which are placed after MAC SubPDU1. Also, terminals 200B and 200C, which support NES functionality, may assume, for example, that the size of the MAC SubPDU placed before the MAC SubPDU of format 1 is 8 bits. Furthermore, the base station 100B may, for example, place only an 8-bit MAC SubPDU (i.e., the MAC SubPDU includes either a subheader containing only the BI field or a subheader containing only the RAPID field) before the MAC SubPDU of format 1.

[0107] Figure 11(B) shows a second example of a MAC PDU, including MAC SubPDUs in existing formats and MAC SubPDUs in new formats. For example, a MAC PDU transmitted by base station 100B consists of three MAC SubPDUs and padding. The first MAC SubPDU (i.e., MAC SubPDU1) is a MAC SubDDU in existing formats for terminal 200A, which does not support NES functionality. The two MAC SubPDUs placed after MAC SubPDU1 (i.e., MAC SubPDU2 and MAC SubPDU3) are MAC SubDDUs in format 2 for terminal 200B and terminal 200C, respectively, which transmit UL-WUS signals and support NES functionality. Furthermore, base station 100B sets the value of the E field of the first MAC SubPDU of format 2 (i.e., MAC SubPDU2) to 0 and the value of the E1 field of the MAC payload to 1 to indicate that there are subsequent MAC SubPDUs. Base station 100B sets the value of the E1 field of the MAC payload of MAC SubPDU3 to 0 to indicate that there are no subsequent MAC SubPDUs. As a result, terminal 200A, which does not support NES functionality, recognizes the subheader of MAC SubPDU2 as the last MAC SubPDU, and determines that everything after the subheader of MAC SubPDU3 is padding, and does not read it. On the other hand, terminals 200B and 200C, which support NES functionality, continue to read the MAC payload of MAC SubPDU2 and MAC SubPDU3. Furthermore, terminals 200B and 200C, which support the functions of NES, may assume that the size of the MAC SubPDU placed before the MAC SubPDU of format 2 is 8 bits. Also, base station 100B may place only an 8-bit MAC SubPDU (i.e., the MAC SubPDU includes either a subheader containing only the BI field or a subheader containing only the RAPID field) before the MAC SubPDU of format 1.

[0108] As described above, in Embodiment 1, terminal 200 receives a first signal from base station 100A forming cell C10A, which includes first setting information for requesting first system information from base station 100B forming cell C10B. Then, terminal 200 transmits a second signal (UL-WUS signal) to the second base station, starts the monitoring window for On-demand SIB1 from a first time corresponding to first information indicating a reference time and a time offset from the reference time, and receives On-demand SIB1. Therefore, it is possible to synchronize the transmission and reception start times of On-demand SIB1 between base station 100 and terminal 200. Because the transmission and reception start times of On-demand SIB1 are synchronized between base station 100 and terminal 200, terminal 200 can receive On-demand SIB1 transmitted from the NES cell. Embodiment 2

[0109] In Embodiment 1, an example was described in which the terminal 200 transmits a second signal (UL-WUS signal), then starts a monitoring window for On-demand SIB1 from a first time according to the reference time and time offset, and receives On-demand SIB1. In Embodiment 2, a first example of specific processing using the reference time and the first time will be described. Note that in Embodiment 2, the wireless communication system, base station, and terminal are the same as in Embodiment 1, so their description will be omitted.

[0110] Base station 100B, when not in sleep mode (for example, when cell C10B is not in sleep mode), periodically transmits SIB1 according to the SIB1 period. The SIB1 period is, for example, a multiple of 20 milliseconds. For example, the SIB1 period is 160 milliseconds. Within one period, base station 100B transmits the same content in SIB1. This transmission method of transmitting the same content in SIB1 within one period is also called SIB1 repetition. In different periods, base station 100B may change the content of the SIB1 it transmits. Before changing the content of SIB1, base station 100B may or may not send an instruction (for example, a system information change: SI change instruction) to terminal 200.

[0111] Furthermore, when the base station 100B is applying power-saving technology for On-demand SIB1 (i.e., entering a sleep state (for example, the sleep state of cell C10B)), it stops the periodic transmission of SIB1. Then, in response to the UL-WUS signal (second signal) from terminal 200, base station 100B transmits the contents of SIB1 as On-demand SIB1. Base station 100B transmits one or more On-demand SIB1 within the monitoring window period of On-demand SIB1. Also, terminal 200 receives one or more On-demand SIB1 within the monitoring window period of On-demand SIB1.

[0112] Furthermore, base station 100B may appropriately change the contents of SIB1 according to the period of SIB1. Therefore, if the monitoring window of On-demand SIB1 spans different SIB1 periods, terminal 200 may receive multiple On-demand SIB1s with different contents within that On-demand SIB1 monitoring window. Also, if the signal condition is poor, terminal 200 may combine and decode multiple On-demand SIB1s. For example, if the SSB reception quality (e.g., RSRP) is lower than a threshold, terminal 200 will combine and decode multiple On-demand SIB1s. However, if terminal 200 combines On-demand SIB1s with different contents, it will not be able to decode them successfully. Therefore, it is necessary to avoid terminal 200 combining and decoding On-demand SIB1s that have different content.

[0113] To avoid terminal 200 combining and decoding On-demand SIB1 with different content, terminal 200 and base station 100B may determine a reference time according to the period of SIB1. Alternatively, terminal 200 and base station 100B may determine a first time, which is the start timing of the monitoring window for On-demand SIB1, based on the period information of SIB1. The reference time determined according to the period of SIB1 will be explained using Figure 12.

[0114] Figure 12 shows an example of a reference time and a first time determined according to the SIB1 period. For example, terminal 200 receives RAR (third signal) from base station 100 until time point T9 of SIB1 period #n. Then, terminal 200 and base station 100B use the start time of the next SIB1 period #n+1, i.e., time T10, as the reference time. In other words, the SFN (System Frame Number) on which the reference time T10 exists satisfies the following equation (2). (Equation 2) SFNmod(T) = 0

[0115] Here, T is the number of frames that make up the period of SIB1, and mod is the operation to find the remainder of the division. Terminal 200 and base station 100B start the monitoring window for On-demand SIB1 by, for example, setting the start time of the first PDCCH occasion of On-demand SIB1 from reference time T10, i.e., time T11, as the first time. Alternatively, terminal 200 and base station 100B may set the time when the next SIB1 period #n+1 starts, i.e., time T10, as the first time. In other words, the SFN in which the first time T10 exists satisfies equation (2). This ensures that the monitoring window of On-demand SIB1 fits within one period, and guarantees that multiple On-demand SIB1 received by terminal 200 contain the same content.

[0116] Furthermore, in order to avoid combining and decoding On-demand SIB1s with different content, terminal 200 may determine whether the monitoring window of an On-demand SIB1 spans different SIB1 periods based on the SIB1 period. If it is determined that it does, terminal 200 will not combine On-demand SIB1s with different periods within the monitoring window of that On-demand SIB1, but will only combine On-demand SIB1s with the same period.

[0117] Furthermore, the base station 100 may, for example, include information regarding the SIB1 period in the first signal or the third signal and transmit it to the terminal 200, or it may include it in a signal different from the first signal and the third signal and transmit it. Alternatively, the information regarding the SIB1 period may be predetermined and stored in the memory unit 130 of the base station 100 and the memory unit 230 of the terminal 200.

[0118] Furthermore, to avoid combining and decoding On-demand SIB1s with different content, base station 100B may ensure that all On-demand SIB1s transmitted within the monitoring window of a single On-demand SIB1 contain the same content, i.e., they are transmitted using the SIB1 repetition method. Also, terminal 200 may assume that multiple On-demand SIB1s received within the monitoring window of a single On-demand SIB1 all contain the same content, i.e., they are transmitted by base station 100B using the SIB1 repetition method. Also, terminal 200 does not need to expect that multiple On-demand SIB1s received within the monitoring window of a single On-demand SIB1 contain different content. Also, terminal 200 does not need to expect that the SIB1 monitoring window spans the cycles of different SIB1s.

[0119] As described above, in Embodiment 2, the terminal 200 can start a monitoring window for On-demand SIB1 from a first time determined according to the period of SIB1 and receive On-demand SIB1. Therefore, for example, the terminal 200 can avoid combining and decoding On-demand SIB1 with different content. In addition, it is possible for the base station 100 and the terminal 200 to synchronize the start times for transmitting and receiving On-demand SIB1. Embodiment 3

[0120] Embodiment 1 describes an example in which, after the terminal 200 transmits a second signal (UL-WUS signal), the monitoring window for On-demand SIB1 is started from a first time according to the reference time and time offset, and On-demand SIB1 is received. Embodiment 2 describes a first example of specific processing using the reference time and the first time. Embodiment 3 describes a second example of specific processing using the first time. In Embodiment 3, the wireless communication system, base station, and terminal are the same as in Embodiments 1 and 2, so their description is omitted.

[0121] Before changing the contents of On-demand SIB1 or other SIBs, base station 100B may send a system information modification instruction (systemInfoModification) to terminal 200 as a fifth signal. Furthermore, if base station 100B wishes to send emergency alert information to terminal 200, it sends an emergency alert information transmission instruction (etwsAndCmasIndication) as a short message as a fifth signal. The fifth signal is a signal containing identification information called P-RNTI (Paging-Network Temporary Identifier) ​​and scrambled DCI. The fifth signal may also be a short message.

[0122] Furthermore, using Figures 13 and 14, we will explain examples of a reference time for determining the start timing of the monitoring window for On-demand SIB1, and a first time which is the start timing of the monitoring window for On-demand SIB1, when base station 100B transmits the fifth signal and terminal 200 receives the fifth signal. Figures 13 and 14 are diagrams showing examples of the reference time and the first time.

[0123] Figure 13 illustrates an example in which the start time of the modification period is set as the reference time or first time when base station 100B transmits a fifth signal containing a system information change instruction, and when terminal 200 receives a fifth signal containing a system information change instruction. The modification period may be called, for example, the BCCH modification period. The boundary of the modification period is defined, for example, by the value of SFN that satisfies the following equation (3). Equation (3) is an equation that shows the condition for determining the reference time or first time in response to the system information change instruction. (Equation 3) SFN mod (m) = 0

[0124] Here, m is the number of frames constituting the correction cycle, and mod is the operation for finding the remainder of the division. Information regarding the number of frames constituting the correction cycle may be included, for example, in the first setting information. Alternatively, information regarding the number of frames constituting the correction cycle may be included, for example, in the On-demand SIB1 received before receiving the fifth signal.

[0125] In Figure 14, for example, terminal 200 receives a fifth signal containing a system information change instruction via PDCCH from base station 100B until time point T12 of correction cycle #n. Regardless of whether terminal 200 transmitted the UL-WUS signal before receiving the fifth signal, terminal 200 and base station 100B use the start of the next correction cycle #n+1, i.e., time point T13, as the reference time. In other words, the value of SFN on which reference time T13 exists satisfies equation (3). Terminal 200 and base station 100B use, for example, the start time of the first PDCCH occasion of On-demand SIB1 from reference time T13, i.e., time point T14, as the first time, and start the monitoring window for On-demand SIB1. Alternatively, terminal 200 and base station 100B may use the start of the next correction cycle #n+1, i.e., time point T13, as the first time.

[0126] Figure 14 shows an example where the time at which the instruction to transmit emergency information was sent and received is used as the reference time, when base station 100B transmits a fifth signal containing an instruction to transmit emergency information, and when terminal 200 receives a fifth signal containing an instruction to transmit emergency information. For example, terminal 200 receives a fifth signal containing an instruction to transmit emergency information from base station 100 via PDCCH up to time point T15 of correction cycle #n. Then, regardless of whether terminal 200 transmitted a UL-WUS signal before receiving the fifth signal, terminal 200 and base station 100B use the end of the last thimble of the PDCCH containing the emergency information instruction, i.e., time T15, as the reference time. Terminal 200 and base station 100B, for example, start the monitoring window for On-demand SIB1 with the first time being the start time of the first On-demand SIB1 PDCCH occasion from reference time T15, i.e., time T16.

[0127] As described above, in Embodiment 3, when the terminal 200 receives a system information change instruction or an instruction to transmit emergency notification information, it can determine a first time in accordance with the received system information change instruction or emergency notification information transmission instruction, start the monitoring window for On-demand SIB1 from the first time, and perform reception of On-demand SIB1. Therefore, it is possible to synchronize the start times for transmitting and receiving On-demand SIB1 between the base station 100 and the terminal 200.

[0128] [Hardware Configuration of Each Device in Each Embodiment] The hardware configuration of each device in the wireless communication system of each embodiment will be described based on Figures 15 to 16.

[0129] Figure 15 shows an example of the hardware configuration of base station 100. As shown in Figure 15, the base station 100 has, as hardware components, an RF (Radio Frequency) circuit 320 equipped with an antenna 310, a CPU (Central Processing Unit) 330, a DSP (Digital Signal Processor) 340, a memory 350, and a network IF (Interface) 360. The CPU is connected via a bus to enable input and output of various signals and data signals. The memory 350 includes at least one of RAM (Random Access Memory), such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data signals.

[0130] The correspondence between the functional configuration of the base station 100 shown in Figure 2 and the hardware configuration of the base station 100 shown in Figure 15 will be explained. The transmitting unit 111 and the receiving unit 112 (or wireless communication unit 110) are realized by, for example, an RF circuit 320, or an antenna 310 and an RF circuit 320. The control unit 120 is realized by, for example, a CPU 330, a DSP 340, a memory 350, and a digital electronic circuit (not shown). Examples of digital electronic circuits include ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), and LSI (Large Scale Integration). The storage unit 130 is realized by, for example, a memory 350. The communication unit 140 is realized by, for example, a network IF 360.

[0131] Figure 16 shows an example of the hardware configuration of terminal 200. As shown in Figure 16, terminal 200 has, as hardware components, an RF circuit 420 equipped with an antenna 410, a CPU 430, a DSP 440, and a memory 450. The memory 450 includes at least one of RAM such as SDRAM, ROM, and flash memory, and stores programs, control information, and data signals.

[0132] The correspondence between the functional configuration of terminal 200 shown in Figure 3 and the hardware configuration of terminal 200 shown in Figure 16 will be explained. The transmitting unit 211 and the receiving unit 212 (or the communication unit 210) are realized by, for example, an RF circuit 420, or an antenna 410 and an RF circuit 420. The control unit 220 is realized by, for example, a CPU 430, a DSP 440, a memory 450, and a digital electronic circuit (not shown). Examples of digital electronic circuits include ASICs, FPGAs, and LSIs. The storage unit 230 is realized by, for example, a memory 450.

[0133] Furthermore, each embodiment may be combined as appropriate, within the bounds of consistency.

[0134] Although each embodiment describes an example of a base station and a terminal, the disclosed technology is not limited to these examples and can be applied to various devices such as electronic equipment mounted on automobiles, trains, airplanes, satellites, electronic equipment transported by drones, robots, AV equipment, home appliances, office equipment, vending machines, and other everyday devices.

[0135] Furthermore, although each embodiment was explained using fifth-generation mobile communication as an example, the disclosed technology is not limited to these. For example, the disclosed technology may be applied to mobile communication of different generations, such as sixth-generation or seventh-generation.

[0136] 1. Wireless Communication System 100, 100A, 100B Base Station C10, C10A, C10B Cell 110 Wireless Communication Unit 111 Transmitter Unit 112 Receiver Unit 120 Control Unit 130 Memory Unit 140 Communication Unit 200, 200A, 200B, 200C, 200D Terminal 210 Communication Unit 211 Transmitter Unit 212 Receiver Unit 220 Control Unit 230 Memory Unit 310 Antenna 320 RF Circuit 330 CPU 340 DSP 350 Memory 360 Network IF 410 Antenna 420 RF Circuit 430 CPU 440 DSP 450 Memory

Claims

1. A terminal device comprising: a receiving unit that receives a first signal from a first base station device forming a first cell, which includes first setting information for requesting first system information from a second base station device forming a second cell; a transmitting unit that transmits a second signal to the second base station device according to the first setting information; and a control unit that determines a first time which is the start timing of a monitoring window for the first system information transmitted from the second base station device, according to a reference time and first information indicating a time offset from the reference time, wherein the control unit controls the terminal device to receive the first system information transmitted from the second base station device within the monitoring window.

2. The terminal device according to claim 1, wherein the control unit controls the monitoring window to start from the first time as a time point after the time offset has elapsed from the reference time, or as a time point corresponding to a specific SSB index after a predetermined time has elapsed from the reference time.

3. The terminal device according to claim 2, wherein the specific SSB index is any of the candidate SSB index, the actually transmitted SSB index, and the actually transmitted SSB index associated with the second signal.

4. The terminal device according to claim 1, wherein the first information is included in the first setting information or is pre-set information.

5. The terminal device according to claim 1, wherein the first setting information is UL-WUS setting information and the second signal is a UL-WUS signal.

6. The receiving unit receives a third signal in response to the second signal, and the first information is included in the third signal, the terminal device according to claim 1.

7. The terminal device according to claim 2, wherein the control unit determines the reference time and the first time according to the period of the first system information.

8. The terminal device according to claim 1, wherein the receiving unit receives a fifth signal including a system information change instruction or an instruction to transmit emergency notification information, and the control unit, upon receiving the fifth signal, determines the first time according to the time at which the fifth signal was received.

9. The terminal device according to claim 1, wherein the first cell is a cell that periodically transmits the first system information, the second cell is an NES cell that stops periodically transmitting the first system information and transitions to a sleep state, the first system information is SIB1, and the first signal is a signal of the RRC layer.

10. A base station device forming a second cell, comprising: a receiving unit that receives a second signal transmitted from a terminal device in accordance with first setting information received by the terminal device from another base station device forming a first cell for requesting first system information from the base station device; and a transmitting unit that transmits the first system information within a monitoring window of the terminal device for the first system information, which is started in accordance with a reference time and first information indicating a time offset from the reference time.

11. A base station device forming a first cell, comprising: a control unit that generates a first signal including first setting information for requesting first system information from another base station device forming a second cell; and a transmission unit that transmits the first signal to a terminal device via the first cell, wherein the control unit causes the terminal device to determine a first time which is the start timing of a monitoring window for the first system information transmitted from the other base station device, the start timing depending on a reference time and first information indicating a time offset from the reference time, the first information being included in the first setting information.

12. A communication system comprising: a first base station device forming a first cell; a second base station device forming a second cell; and a terminal device that receives a first signal from the first base station device including first setting information for requesting first system information from the second base station device, and transmits a second signal to the second base station device according to the first setting information, wherein the terminal device determines a first time which is the start timing of a monitoring window for the first system information transmitted from the second base station device, according to a reference time and first information indicating a time offset from the reference time, and controls the terminal device to receive the first system information transmitted from the second base station device within the monitoring window.

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