Terminal device for acquiring system information in power-saving cellular communication network, and control method

Abstract

According to the present invention, a terminal device of a cellular communication system: transmits a random access preamble (RAP) as Wake Up Signal (WUS) to a base station device that does not periodically transmit System Information Block Type 1 (SIB1) in the cellular communication system; receives first downlink control information (first DCI) or first physical downlink control information (first PDCCH) for receiving a random access response (RAR); executes processing for receiving the RAR using the first DCI or the first PDCCH; receives a second DCI or a second PDCCH for receiving the SIB1; and executes processing for receiving the SIB1 using the second DCI or the second PDCCH. The terminal device: receives a parameter for receiving the first DCI or the first PDCCH, or the second DCI or the second PDCCH, from a second base station device that periodically transmits SIB1; receives the second DCI or the second PDCCH when the RAR is received, and receives the SIB1; and does not receive the second DCI and the second PDCCH when the RAR is not received.

Description

Terminal device for acquiring system information in a power-saving cellular communication network and control method

[0001] The present invention relates to a technology for transmitting and receiving system information in a power-saving cellular communication network.

[0002] Technologies for saving power consumption in networks are being studied in wireless communication systems that comply with the cellular communication standards of the Third Generation Partnership Project (3GPP (registered trademark)). Such technologies include, for example, preventing the transmission of System Information Block Type 1 (SIB1), which is to be periodically transmitted in each cell, in some cells. Non-Patent Document 1 describes an on-demand SIB1 technology in which, for a cell in which SIB1 is not transmitted, a terminal device requests the transmission of SIB1 from a base station device that serves that cell.

[0003] 3GPP contribution, RP-230645

[0004] A terminal device transmits a Wake Up Signal (WUS) when requesting the transmission of SIB1, but the processing between the transmission of the WUS and the reception of SIB1 is not necessarily clear, and it is important that communication control is performed efficiently.

[0005] The present invention provides a technique that enables efficient application of on-demand SIB1 technology.

[0006] A terminal device according to one aspect of the present invention is a terminal device for a cellular communication system, and includes: a transmitting means for transmitting a random access preamble (RAP) as a wake-up signal (WUS) to a base station device that does not periodically transmit a system information block type 1 (SIB1) in the cellular communication system; and a receiving means for, when a random access response (RAR) is received in response to the WUS, receiving downlink control information (DCI) specifying a frequency and time resource in which the SIB1 is to be transmitted, not receiving the DCI if the RAR is not received, and receiving the SIB1 based on the DCI if the DCI is received.

[0007] According to the present invention, the on-demand SIB1 technology can be efficiently applied.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0009] The accompanying drawings are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention, and together with the description are used to explain the principles of the present invention. Figure 1 is a diagram showing an example of the configuration of a wireless communication system. Figure 2 is a diagram showing an example of the flow of processing executed in the wireless communication system. Figure 3 is a diagram showing an example of the configuration of a cell list notified to a terminal device. Figure 4 is a diagram showing an example of the configuration of a WUS configuration. Figure 5 is a diagram showing an example of the flow of processing executed in a terminal device. Figure 6 is a diagram showing an example of the hardware configuration of a base station device and a terminal device. Figure 7 is a diagram showing an example of the functional configuration of a terminal device. Figure 8 is a diagram showing an example of the functional configuration of a base station device.

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0011] (System Configuration) FIG. 1 shows an example configuration of a wireless communication system according to this embodiment. This wireless communication system is a cellular communication system conforming to a cellular communication standard such as Long Term Evolution (LTE) of the Third Generation Partnership Project (3GPP (registered trademark)), fifth generation (5G), or a successor standard thereof. The wireless communication system includes, for example, a base station device 101, a base station device 121, a base station device 122, and a terminal device 141. Note that FIG. 1 is merely an example, and naturally, many more base station devices and terminal devices may exist. Here, for power saving control, the base station device 121 and the base station device 122 are configured not to periodically transmit System Information Block Type 1 (SIB1), but to transmit SIB1 only upon receiving a request from the terminal device 141. Hereinafter, the cells 131 and 132 provided by the base station device 121 and the base station device 122, which do not periodically transmit SIB1, are referred to as Network Energy Saving (NES) cells. Note that the base station device 121 and the base station device 122 of the NES cell do not periodically transmit SIB1, but may periodically transmit, for example, a synchronization signal (SS) or a physical broadcast channel (PBCH) including a master information block (MIB). Furthermore, the base station device 121 and the base station device 122 of the NES cell terminate their power saving operation in response to receiving a specific signal called a wake-up signal (WUS) from the terminal device 141, and operate to transmit, for example, SIB1 so as to be able to communicate with the terminal device 141. When SIB1 is transmitted, the SIB1 may be broadcast or may be transmitted individually to the terminal device 141 that is the source of the WUS. Furthermore, the terminal device 141 may transmit a random access (RA) preamble (RA preamble, or RAP) as the WUS.The terminal device 141 may transmit a WUS (RAP) in an RRC Inactive state or an RRC Idle state, or may transmit a WUS (RAP) while operating in an RRC Connected state in which a T311 timer used for performing reconnection processing is running due to, for example, a Radio link failure.

[0012] On the other hand, the base station device 101 does not perform power saving control and periodically transmits SIB1. Hereinafter, the cell 111 provided by the base station device 101 may be referred to as a non-NES cell. The terminal device 141 can receive the periodically transmitted SIB1 related to the non-NES cell without transmitting WUS, for example. Note that the terminal device 141 can acquire, from the base station device 101, a WUS configuration including setting information for a random access procedure in a cell provided by a base station device of the NES cell (at least one of the base station device 121 and the base station device 122), for example.

[0013] The base station device of the NES cell transmits SIB1 in response to receiving a WUS (RAP). In response to transmitting the WUS, the terminal device 141 performs a reception process for SIB1. Meanwhile, the WUS transmitted from the terminal device 141 may not reach the base station device of the NES cell. In this case, the base station device of the NES cell cannot receive the WUS and therefore does not transmit SIB1. In this case, the terminal device 141 needs to retransmit the WUS in order to receive SIB1. Furthermore, configuration information for transmitting the WUS needs to be notified to the terminal device 141, and when this configuration information is updated, the configuration information needs to be appropriately notified to the terminal device 141. Various operations, including these operations, need to be appropriately defined in order to efficiently transmit and receive SIB1 using WUS. In consideration of these circumstances, this embodiment provides a procedure for efficiently transmitting and receiving SIB1 using WUS.

[0014] (Processing Flow) Fig. 2 shows an example of the processing flow executed in the wireless communication system of this embodiment. First, the terminal device 141 receives WUS configuration information (WUS configuration) for a NES cell (e.g., the cell 131 provided by the base station device 121) from the base station device 101 of a non-NES cell (S201). In one example, the WUS is a RAP, and the WUS configuration includes configuration information related to the random access procedure, such as radio resources for transmitting the RAP and information on the sequence to be used for generating the RAP. Note that resources for WUS that are different from time and frequency resources used for transmitting the RAP for establishing a connection may be prepared. Furthermore, in addition to or instead of this, a sequence different from the sequence used for generating the RAP for establishing a connection may be prepared as the sequence used for generating the RAP for WUS.

[0015] In one example, the WUS configuration can be notified to the terminal device 141 by an SIB transmitted in a non-NES cell. That is, the WUS configuration can be broadcast by a base station device of a non-NES cell that does not stop periodic transmission of SIB1. In this case, the non-NES cell can be referred to as an anchor cell. For example, for an unconnected terminal device 141 located in a non-NES cell (e.g., cell 111), the WUS configuration can be provided in the SIB of the non-NES cell.

[0016] Furthermore, the WUS configuration may be notified to the terminal device 141 in an unconnected state or a connected state (for example, residing in an NES cell) using a radio resource control (RRC) message or other message transmitted in an NES cell or a non-NES cell. For example, the WUS configuration may be notified to the terminal device 141 by an RRC release message. That is, the WUS configuration may be notified to the terminal device 141 by an individual message when the terminal device 141 transitions from a connected state (RRC Connected state) to an unconnected state (RRC Inactive or RRC Idle state). Also, in one example, information on the WUS configuration to be used thereafter may be stored in the On-demand SIB1 or other SIBs (SIB3, SIB4, etc.) transmitted in the NES cell and transmitted to the terminal device 141. In this case, WUS configuration information of the NES cell to which the terminal device 141 is connected may be stored, or WUS configuration information of a neighboring NES cell may be stored. Note that, for example, when the terminal device 141 connected to an NES cell (e.g., cell 131) transitions from an RRC Connected state to an RRC Idle state, there may be a case where the terminal device 141 should move to that NES cell the next time it enters the RRC Connected state. In this case, the base station device 121 of the NES cell may transmit an RRC release message including the WUS configuration. Also, when the terminal device 141 connected to a non-NES cell (e.g., cell 111) transitions from the RRC Connected state to the RRC Idle state, there may be a case where the terminal device 141 should be instructed to move to the NES cell (e.g., cell 131). In this case, the base station device 101 of the non-NES cell may transmit an RRC release message including the WUS configuration of the NES cell to the terminal device 141.

[0017] Furthermore, in the above example, when multiple NES cells exist (for example, as neighboring cells) as shown in FIG. 1 , multiple WUS configurations for each of the multiple NES cells may be notified to the terminal device 141 from the network (for example, a base station device of a non-NES cell or at least one of the base station devices of the NES cells). Note that a WUS configuration for an NES cell that is not neighboring the cell to which the WUS configuration is transmitted may be notified to the terminal device 141. Note that WUS configurations for multiple NES cells may be notified collectively to the terminal device 141. In this case, a common WUS configuration may be notified for the multiple NES cells, or individual WUS configurations may be notified for each NES cell. Furthermore, one WUS configuration may be used as a reference, and a difference value may be notified for other WUS configurations. When receiving a WUS configuration, the terminal device 141 may associate the information with an identifier of the cell from which the information was received and retain the information. In one example, when the terminal device 141 receives a WUS configuration including information about an adjacent NES cell while connected to a non-NES cell, the terminal device 141 may associate an identifier (e.g., a physical identifier such as PCI) that can uniquely identify the connected non-NES cell with the WUS configuration and retain the WUS configuration. Furthermore, when the terminal device 141 receives multiple WUS configurations, the terminal device 141 may retain the multiple WUS configurations in association with information identifying the cell when the WUS configurations were received. For example, it is assumed that the terminal device 141 receives a WUS configuration in a non-NES cell formed by the base station device 101, and then reselects a cell (non-NES cell or NES cell) formed by a base station device other than the base station device 101.At this time, if the terminal device 141 receives a new WUS configuration after the reselection, it can retain the WUS configuration associated with the cell before the reselection and the WUS configuration associated with the cell after the reselection. Note that the terminal device 141 may receive the WUS configuration in any of the RRC Inactive state, the RRC Idle state, and the RRC Connected state. Note that in the RRC Connected state, when the T311 timer is running, the terminal device 141 receives the MIB of the NES cell at the time of cell reselection, but it is possible that the terminal device 141 does not receive the WUS configuration. For example, if there is no WUS configuration corresponding to the cell (or its physical cell identifier) ​​for which the terminal device 141 has received an MIB, the terminal device 141 may exclude the cell from the targets for WUS transmission, or may regard the cell as a barred cell (a cell to which access is prohibited) for a certain period of time.

[0018] The WUS configuration may include, for example, configuration information (RACH configuration) for a random access procedure required for transmitting WUS, a ValueTag for determining whether an update has been performed, and a timer value for determining an expiration date. Note that this is just an example, and some of this information may be omitted. Furthermore, the configuration information including the WUS configuration may include information indicating which NES cells each of one or more WUS configurations applies to. For example, information indicating which cells each WUS configuration applies to may be included as information for identifying cells in the neighbor cell list notified in SIB3 or SIB4. In one example, neighbor cell information may be included in SIB3, and WUS information may be included in a newly defined SIBx. FIG. 3 shows an example in which information on four NES cells of the same frequency (physical cell identifier (physCellId) = 127 to 130) is included and transmitted in SIB3. If a cell cannot be uniquely identified by the physical cell identifier alone, the cell may be identified by combining it with the ARFCN-ValueNR that identifies the frequency of the NES cell. As an example, it is shown that a cell with a physical cell identifier of 131 is not an NES cell. FIG. 4 shows an example of two WUS configurations that are included and transmitted in SIBx. In addition to identification information (Config id), these WUS configurations include, as described above, for example, Value Tag, RACH configuration, and Timer. The WUS configuration also includes an associated cell list that indicates which cells the configuration information is associated with. For example, WUS configuration[1] with Config id = 0x01 includes associated cell list = 0, 2. This indicates that WUS configuration[1] is associated with the cells in intraFreqNeighBellList[0] and intraFreqNeighBellList[2] indicated in SIB3.That is, WUS configuration [1] is applied to two NES cells with physCellId = 127 and physCellId = 129. Similarly, the example of Fig. 4 shows that WUS configuration [2] with Config id = 0x02 is applied to two NES cells with physCellId = 128 and physCellId = 130. Although Fig. 3 illustrates an example of NES cells with the same frequency, information for identifying a cell may also be transmitted to the terminal device 141 using interFreqNeighborCellList in the same manner as the above-described procedure for neighboring NES cells with different frequencies.

[0019] According to this method of notifying configuration information, there is no need to notify the physCellId redundantly in the SIBx that notifies the WUS configuration. This makes it possible to reduce signaling overhead between the terminal device and the base station device. In addition, in the above example, a case has been described in which the WUS configuration is included in a newly defined SIBx, but this is not limiting. For example, the WUS configuration may be included in an existing SIB such as SIB3 or SIB4 and transmitted. Note that a similar method can also be applied when the WUS configuration is transmitted in a message other than an SIB. That is, regardless of the message in which the information is transmitted, a first list is prepared in which one or more NES cells are indexed and listed, and a second list is prepared in which one or more WUS configurations are indicated. In the second list, the NES cells to which each of the WUS configurations is applied can be specified by the indexes used in the first list.

[0020] The Timer value included in each WUS configuration can be used to indicate the expiration date for the terminal device 141 to determine whether the WUS configuration is valid. In the example of Fig. 4, the Timer value is set to 3 hours for WUS configuration [1] and 2 hours for WUS configuration [2]. The terminal device 141 starts the timer when acquiring a WUS configuration, and deletes (or invalidates) the WUS configuration it holds when the notified timer value expires. Furthermore, the terminal device 141 can perform a process to reacquire the WUS configuration as necessary (for example, when the WUS configuration is within the range of the corresponding NES cell). For example, the terminal device 141 may acquire the WUS configuration transmitted in a non-NES cell and newly store the information. The terminal device 141 may also receive the WUS configuration by, for example, performing a process such as establishing a connection with a non-NES cell or an NES cell. It is possible that the terminal device 141 may be unable to update the WUS configuration because it is unable to communicate with the cell in which it was located while the T311 timer is running in the RRC Connected state. In this case, the terminal device 141 may consider the WUS configuration that it previously received and stored to be valid.

[0021] The terminal device 141 may manage the expiration date of the WUS configuration in association with the SIB. That is, the 3GPP (registered trademark) protocol specifies an expiration date for the SIB, such as three hours, and the terminal device is to reacquire the SIB upon expiration of the SIB. This expiration date of the SIB may also be used as the expiration date of the WUS configuration. For example, the terminal device may delete the SIB it holds and the WUS configuration it holds upon expiration of the SIB after acquiring it. Then, when reacquiring the SIB as needed, the terminal device may also reacquire the WUS configuration. For example, when the terminal device 141 is in a state where it should acquire an SIB, the terminal device 141 may be configured to acquire a WUS configuration and transmit a WUS in accordance with the WUS configuration to acquire SIB 1. Furthermore, before the expiration date of the SIB and when the time remaining until the expiration date has reached a predetermined length, the terminal device 141 may transmit a WUS using the WUS configuration it holds, execute a process to acquire SIB 1, and acquire a new WUS configuration.

[0022] The Value Tag included in each WUS configuration is a value used by the terminal device 141 to determine whether the received WUS configuration contains setting values ​​that differ from those of a WUS configuration previously acquired and stored in the terminal device 141. That is, the terminal device 141 can determine, based on the value of the Value Tag, whether the setting values ​​of the currently stored WUS configuration are valid values ​​that have not been updated. If the Value Tag of the currently stored WUS configuration differs from the received Value Tag, the terminal device 141 can determine that the stored WUS configuration contains old setting values ​​and not use those setting values. Furthermore, if the Value Tag of the currently held WUS configuration is the same as the received Value Tag, the terminal device 141 may determine that the setting values ​​of the held WUS configuration are unchanged and valid, and may use those setting values. For example, when the terminal device 141 receives the WUS configuration (WUS configuration[1]) with Config id = 0x01 shown in Fig. 4, it holds that WUS configuration together with its Value Tag = 0x01. Then, when the terminal device 141 subsequently receives a WUS configuration with Config id = 0x01, it checks its Value Tag. If the Value Tag is 0x01, the terminal device determines that the setting values ​​of the WUS configuration have not changed and that there is no need to update the WUS setting values ​​it holds. On the other hand, if the Value Tag is a value other than 0x01, such as 0x02, the terminal device determines that the setting values ​​of the WUS configuration have been updated and that there is a need to update the WUS setting values ​​it holds. In this case, the terminal device updates the WUS setting values ​​it holds internally using the received WUS configuration with a Value Tag of 0x02.Furthermore, in response to updating the WUS setting value, the terminal device may start a timer for determining the expiration date of the setting value. Note that the terminal device 141 may perform the above-described processing when, while in the coverage area of ​​the cell formed by the base station device 101, it receives and retains a WUS configuration, and then receives a new WUS configuration after transitioning to another cell. In one example, the terminal device 141 may receive a WUS configuration in the cell formed by the base station device 101, and after transitioning to another cell (e.g., a non-NES cell or an NES cell), continue to retain the WUS configuration stored before the transition without deleting it. Thereafter, the terminal device 141 may update the WUS configuration according to the procedure using the Value Tag or timer described above.

[0023] Returning to FIG. 2 , the terminal device 141 performs cell reselection between the non-NES cell (cell 111) and the NES cells (cells 131 and 132) (or between other cells, if any, not shown) (S202). At this point, the base station device of the NES cell does not transmit SIB1, but transmits an SS / PBCH Block (SSB). This allows the terminal device 141 to perform cell reselection from a group of cells including the NES cell transmitting the SSB. Here, the terminal device 141 determines, for example, whether to perform cell reselection from the non-NES cell currently serving the NES cell to the NES cell. The terminal device 141 then receives an MIB periodically transmitted by the base station device of the NES cell (S203). The terminal device 141 can, for example, check CellBarred information related to connection restrictions contained in the MIB and determine whether to transmit a WUS to the NES cell. That is, if connection is prohibited in the NES cell, the terminal device 141 determines that it cannot transmit a WUS to that NES cell. On the other hand, if connection is not prohibited in the NES cell, the terminal device 141 determines that it can transmit a WUS and transmits a WUS to the base station device of that NES cell. Here, it is assumed that connection is not restricted in the NES cell, and the terminal device 141 has decided to transmit a WUS to that NES cell (S204). In accordance with this decision, the terminal device 141 transmits a WUS (RAP) to the base station device of the NES cell (S205). The terminal device 141 generates a RAP based on, for example, setting information related to the random access procedure included in the WUS configuration received in S201, and transmits the RAP to the base station device of the NES cell using radio resources for transmitting the RAP. In addition, in the cell selection / cell reselection of the reconnection process, the terminal device 141 can consider an NES cell that stops periodic transmission of SIB1 as a candidate cell for reconnection. In this case, the terminal device 141 transmits the above-mentioned RAP to the base station device of the NES cell during the reconnection process. In addition, in this case, the terminal device 141 can preferentially treat non-NES cells that do not need to transmit a RAP as candidate cells for the reconnection process compared to NES cells that need to transmit a RAP.

[0024] The base station device of the NES cell can transmit an RA response (RA response, RAR) in response to receiving the WUS. The resources on which the PDCCH (DCI) transmitting information necessary for receiving the RAR is transmitted can be notified to the terminal device 141 by, for example, an MIB. The terminal device 141 can receive the PDCCH (DCI) for receiving the RAR from the base station device of the NES cell (S206), and can receive the RAR based on the information specified by the PDCCH (DCI) (S207).

[0025] The terminal device 141 may set a window (RAR window) indicating a time interval for receiving the RAR, and may attempt to receive the RAR within that window. If the terminal device 141 is unable to receive the RAR within this window, it may determine that the base station device of the NES cell did not receive the WUS, and may retransmit the WUS to that base station device. The base station device of the NES cell or non-NES cell may include the setting value of the RAR window (e.g., ra-ResponseWindow) in setting information such as WUS configuration, and notify the terminal device 141 of this. The terminal device 141 may perform window control starting from the frame (System Frame Number, SFN) or slot (slot number) that transmitted the WUS. The terminal device 141 performs RAR detection and reception processing within this window period. The base station device of the NES cell transmits a PDCCH (DCI) including RAR scheduling information, for example, in the frequency and time resource notified to the terminal device 141 in the MIB, and transmits the RAR to the terminal device 141 using the PDSCH according to the scheduling information. Note that the terminal device 141 receives the frequency and time resource for identifying the PDCCH (DCI) for transmitting and receiving the RAR from the ra-SearchSpace included in the MIB transmitted by the base station device of the NES cell. The terminal device 141 receives the PDCCH (DCI) including the RAR scheduling information by monitoring the Type 1 PDCCH Common Search Space according to the information. At this time, the base station device of the NES cell can transmit the RAR including information of CORESET0 including resource information of the PDCCH (DCI) necessary for the terminal device 141 to receive the On-demand SIB1. The terminal device 141 receives the PDCCH (DCI) using the information of CORESET0, and receives SIB1 according to the setting information included in the received PDCCH (DCI). Note that if the terminal device 141 determines that it was unable to receive the RAR in the RAR window, it can retransmit the WUS to the base station device of the NES cell.In addition, when ra-SearchSpace is not included in the MIB and CORESET0 is included in the MIB, the terminal device 141 receives the information in CORESET0 (Type0 PDCCH Common Search Space) indicating the frequency and time resources for receiving the PDCCH for SIB1 included in the MIB, and can receive the PDCCH (DCI) for transmitting and receiving the RAR in the frequency and time resources specified by the information. Thereafter, the terminal device 141 may execute the above-mentioned reception process of SIB1.

[0026] Then, after receiving the RAR, the terminal device 141 can receive SIB1 (On-demand SIB1) from the base station device. SIB1 can acquire information necessary for its reception by receiving downlink control information (DCI) on the physical downlink control channel (PDCCH). Note that information indicating the frequency and time resources for receiving the PDCCH for SIB1 is also called CORESET0 (Type0 PDCCH Common Search Space). This information is transmitted from the base station device of the NES cell to the terminal device 141, for example, by MIB.

[0027] DCI format 1_0 with CRC scrambled by RA-RNTI may be used to notify the scheduling information of the PDSCH in which the RAR is transmitted, and DCI format 1_0 with CRC scrambled by SI-RNTI may be used to notify the scheduling information of the PDSCH in which the SIB1 is transmitted. That is, the DCI used in the scheduling information of the PDSCH for the RAR is a DCI of format 1_0 with a cyclic redundancy check (CRC) scrambled by the radio network temporary identifier (RNTI) for random access (RA). Also, the DCI used in the scheduling information of the PDSCH for SIB1 is a DCI of format 1_0 with a CRC scrambled by the RNTI for system information (SI). Furthermore, information on CORESET0 for the terminal device 141 to receive scheduling information for the PDSCH on which the RAR is transmitted can be notified to the terminal device 141, for example, by an MIB.

[0028] Note that information on CORESET0 for SIB1 may be transmitted to the terminal device 141 in the RAR, or may be transmitted to the terminal device 141 by MIB, WUS configuration, or the like. For example, after transmitting the RAR, the base station device of the NES cell transmits a PDCCH (DCI) including information for specifying the frequency and time resources (resource blocks) to be used for transmitting the RAR and SIB1 in CORESET0 specified in the RAR. In addition, the base station device of the NES cell transmits SIB1 (On-demand SIB1) in the resources of the Physical Downlink Shared Channel (PDSCH) indicated by the PDCCH (DCI) transmitted in CORESET0. After receiving the RAR (S207), the terminal device 141 receives a PDCCH (DCI) in CORESET0 (S208) and receives SIB1 in the PDSCH resource indicated by the PDCCH (DCI) (S209). Note that, in a state where the terminal device 141 has not received the RAR, the terminal device 141 may attempt to receive DCI at the resource position of CORESET0 for SIB1 and confirm the resource on which SIB1 is transmitted. That is, in the above example, an example is described in which the terminal device 141 transmits a RAP, receives an RAR (and the corresponding DCI), and then receives the DCI for SIB1 and SIB1, but reception of the RAR (and the corresponding DCI) may be omitted. In this case, information on CORESET0 for SIB1 can be notified to the terminal device 141 in advance by, for example, an MIB in an NES cell or a non-NES cell. This allows the terminal device 141 to immediately proceed to receiving processing of SIB1 after transmitting a RAP, and to quickly perform receiving processing of SIB1. Furthermore, if the terminal device 141 does not receive an RAR after transmitting a RAP, it may not perform processing related to receiving SIB1, such as checking DCI at the resource position of CORESET0 for SIB1. In this case, if the terminal device 141 does not receive an RAR after transmitting a WUS (RAP), it may transmit a WUS again, and after receiving the RAR, perform processing related to receiving SIB1, such as checking DCI.This allows the base station device of the NES cell to receive DCI related to SIB1 and SIB1 after it is confirmed that it has received WUS (RAP).

[0029] In the above example, the case where information on the Type 1 PDCCH Common Search Space and CORESET0 related to SIB1 indicated by the ra-SearchSpace required for receiving the RAR of the NES cell is included in the MIB transmitted in the NES cell has been described, but this is just one example. For example, the information may be included in the WUS configuration. For example, a base station device of a non-NES cell (anchor cell) includes information on the Type 1 PDCCH Common Search Space and CORESET0 related to SIB1 indicated by the ra-SearchSpace required for receiving the RAR of the NES cell in the WUS configuration and transmits it to the terminal device 141. Note that the base station device of the non-NES cell may transmit, separately from the WUS configuration (in the same message or a different message), information on the Type 1 PDCCH Common Search Space and CORESET0 related to SIB1 indicated by the ra-SearchSpace necessary for receiving the RAR of the NES cell to the terminal device 141. After transmitting the WUS, the terminal device 141 can receive DCI including the RAR and SIB1 schedule information based on the information on the Type 1 PDCCH Common Search Space and CORESET0 indicated by the ra-SearchSpace received from the base station device of the non-NES cell. In addition, when ra-SearchSpace is not included in the WUS configuration, the terminal device 141 may receive DCI including the schedule information of RAR and SIB1 based on the information of CORESET0 necessary for receiving SIB1. Also, the terminal device 141 may receive DCI including the schedule information of RAR and SIB1 in an RRC Inactive state or an RRC Idle state, but this is not limited to this. For example, in an RRC Connected state, the terminal device 141 may receive DCI including the schedule information of RAR and SIB1 while a T311 timer used to perform reconnection processing is running due to a reason such as a Radio link failure.In addition, if the T311 timer expires before receiving a DCI or RAR including schedule information for the RAR, the terminal device 141 may cancel the DCI reception process or the RAR reception process and transition to an RRC Inactive state or an RRC Idle state. Also, if the T311 timer expires before receiving a DCI or SIB1 including schedule information for SIB1, the terminal device 141 may cancel the DCI reception process or the RAR reception process and transition to an RRC Inactive state or an RRC Idle state. Furthermore, if the T311 timer expires while processing an On-demand SIB1, the terminal device 141 transitions from an RRC Connected state to an RRC Idle state, but may continue processing the On-demand SIB1 at this time. In this case, the terminal device 141 may, for example, receive an RAR for a WUS (RAP) transmitted in the RRC Connected state in the RRC Idle state. The terminal device 141 may receive the RAR in the RRC Connected state and, after transitioning to the RRC Idle state, receive the On-demand SIB1. That is, the terminal device 141 may continue processing the On-demand SIB1 regardless of changes in the RRC state. When the terminal device 141 continues processing as described above, it is not necessary to restart the processing of the On-demand SIB1 from the beginning after transitioning to the RRC Idle state. This eliminates the need for the terminal device 141 to process the On-demand SIB1. This reduces the time required for the terminal device 141 to process the On-demand SIB1. Also, in the above example, an example in which the T311 timer expires has been described, but the terminal device 141 may be triggered by the completion of reception processing of each piece of information, rather than by the expiration of the T311 timer. For example, the terminal device 141 may transition to the RRC Inactive state or the RRC Idle state after receiving a DCI or RAR including schedule information of an RAR, or by the completion of DCI reception processing including schedule information of SIB1, and continue processing on-demand SIB1.

[0030] Furthermore, the terminal device 141 may acquire, through the DCI related to SIB1 described above, not only information about the resource blocks in which SIB1 is transmitted, but also information about the transmission period of SIB1. Furthermore, the terminal device 141 may acquire information about the time interval (window) in which reception processing of SIB1 should be performed in advance from the base station device of the NES cell (or, in some cases, the base station device of a non-NES cell). When the information about the window is notified to the terminal device 141 from the network, it may be included in the MIB or in the WUS configuration (or other information element). Furthermore, the window may be fixedly defined, for example, by a standard or the like. The terminal device 141 may execute reception processing of SIB1 within the window, starting from, for example, the transmission time of the WUS. That is, the terminal device 141 may start window control starting from the frame (SFN) or slot (slot number) in which the WUS was transmitted. Furthermore, the terminal device 141 may set an offset and start window control after a certain period of time. The offset may be, for example, an offset based on the start slot of the RAR window required for RAR reception, or an offset based on the slot in which the RAR is received. In this case, the terminal device 141 does not need to monitor DCI for receiving SIB1 during the offset period. This offset information may be included in the WUS configuration or the RAR. The terminal device 141 performs reception processing for SIB1 within the above-mentioned time interval (window). If the terminal device 141 is unable to receive SIB1 within this interval (for example, if it does not detect SIB1, fails to decode SIB1, or is unable to receive DCI for receiving SIB1), it retransmits the WUS.

[0031] In the above example, the terminal device 141 determines whether reception of SIB1 is successful or unsuccessful based on whether it can receive SIB1 within a certain time period (window). However, this is not limiting. For example, an upper limit on the number of reception attempts for SIB1 may be set, and the success or failure of reception of SIB1 may be determined based on the upper limit. In this case, the terminal device 141 acquires information indicating the upper limit on the number of reception attempts in advance from a base station device (of a non-NES cell or NES cell). Then, if the terminal device 141 is unable to receive SIB1 even after performing the reception process the upper limit number of times, it determines that reception of SIB1 has failed and retransmits the WUS. For example, the terminal device 141 monitors the time and frequency resources in which SIB1 should be transmitted according to the transmission period of SIB1 and performs the reception process. Then, if the terminal device 141 does not detect SIB1 in the resource or fails to decode the received signal, it determines that the reception process of SIB1 has failed and increments the number of reception attempts by 1. For example, the terminal device 141 may set the number of reception attempts to an initial value of 0 after transmitting a WUS, increment the number by 1 each time a reception process is attempted, and determine that reception of SIB1 has failed when the number of reception attempts reaches the upper limit. Note that, when information on the upper limit of the number of reception attempts is notified to the terminal device 141 from the network, it may be included in the MIB or in the WUS configuration (or other information element). Furthermore, information on the upper limit of the number of reception attempts may be fixedly defined by a standard or the like, in which case the upper limit may be predefined in a control program related to communication of the terminal device 141.

[0032] Furthermore, if the PDCCH (DCI) received according to the information of CORESET0 related to SIB1 includes only information on the resource blocks of SIB1 (for example, does not include periodicity information), the terminal device 141 performs reception processing for SIB1 only in those resource blocks and can determine whether reception of SIB1 was successful or unsuccessful. In this case, the terminal device 141 does not need to acquire parameters such as information on the reception time interval (window) of SIB1 or the upper limit of the number of reception attempts for SIB1. Note that in this case, DCI format 1_0 with CRC scrambled by SI-RNTI, which is used to notify conventional scheduling information of SIB1, can be used as the DCI.

[0033] In addition, when the terminal device 141 retransmits a WUS in response to not receiving an RAR after transmitting a RAP, it may not determine whether reception of SIB1 was successful or unsuccessful and may not retransmit the WUS based on the determination result. That is, the terminal device 141 may only retransmit the WUS based on the determination of failure in reception of the RAR, and may not retransmit based on SIB1. An example of processing performed by the terminal device 141 in this case is shown in Figure 5. After transmitting a WUS (RAP) (S501), if the terminal device 141 does not receive an RAR (NO in S502), the terminal device 141 retransmits the WUS (S501) without performing processing for receiving SIB1, such as checking CORESET0 for SIB1 (receiving DCI). On the other hand, if the terminal device 141 receives an RAR (YES in S502) after transmitting a WUS (RAP) (S501), it receives DCI related to SIB1 (S503). Then, the terminal device 141 executes a reception process for SIB1 (S504). If the reception is unsuccessful (NO in S505), it retries reception of SIB1 without retransmitting the WUS (S503, S504). On the other hand, if the terminal device 141 successfully receives SIB1 (YES in S505), it stores the configuration information included in SIB1 and terminates the process. Note that this is just an example, and the terminal device 141 may perform both a WUS retransmission determination based on the success or failure of RAR reception and a WUS retransmission determination based on the success or failure of SIB1 reception. That is, Figure 5 shows an example in which WUS is not retransmitted if SIB1 is not successfully received, but the terminal device 141 may return the processing to S501, for example, if it fails to receive SIB1 (NO in S505).

[0034] Note that the terminal device 141 can gradually increase the transmission power when retransmitting a WUS. A base station device of an NES cell or a non-NES cell can notify the terminal device 141 in advance of an increase amount of transmission power (e.g., powerRampingStep) in the WUS configuration. The terminal device 141 can increase the transmission power according to the increase amount each time the WUS is retransmitted.

[0035] If the terminal device 141 fails to receive SIB1 transmitted by the NES cell despite having retransmitted the WUS until the maximum number of retransmissions is reached, the terminal device 141 may terminate the retransmission process. For this purpose, the base station device of the NES cell or non-NES cell may notify the terminal device 141 in advance of information on the maximum number of retransmissions. Information on the maximum number of retransmissions (e.g., preambleTransMax) may be included in the WUS configuration and notified to the terminal device 141. After the retransmissions are completed, the terminal device 141 may consider the NES cell to be a barred cell (a cell to which access is prohibited) for a certain period of time, and may not select the NES cell during cell reselection, etc. Then, the terminal device 141 may determine whether to transmit the WUS to another NES cell. Furthermore, if the terminal device 141 is unable to receive SIB1 even after transmitting the WUS using the maximum transmission power, the terminal device 141 may terminate the WUS transmission process even if the maximum number of retransmissions has not been reached.

[0036] Furthermore, the terminal device 141 may terminate the reception process of the PDCCH (DCI) including the scheduling information of SIB1 in response to successful reception of SIB1. Note that, when the terminal device 141 fails to receive SIB1 and performs the reception process again, it receives the PDCCH (DCI) including the scheduling information of SIB1 again and performs the reception process of SIB1 again based on that information. Note that, when receiving the PDCCH (DCI) for receiving SIB1 in response to receiving the RAR, the terminal device 141 may determine whether reception of SIB1 has succeeded or failed using a window or the number of reception attempts, as described above. If a window is used, the start timing of the window may be the reception timing of the RAR, rather than the transmission timing of the WUS.

[0037] Furthermore, instead of or in addition to when the number of WUS retransmissions reaches the maximum number of retransmissions, the terminal device 141 may also terminate the WUS transmission process and the RAR or SIB1 reception process when cell reselection to another cell (other than the NES cell that transmitted the WUS) is performed during WUS transmission (initial transmission or retransmission). In this case, the terminal device 141 may perform cell reselection to another cell after completing the process from WUS transmission to RAR or SIB1 reception. Furthermore, if cell reselection to another cell occurs after WUS transmission, the terminal device 141 may terminate or interrupt the RAR or SIB1 reception process.

[0038] It should be noted that when performing a cell reselection process from a non-NES cell to an NES cell, it is assumed that the terminal device 141 receives a paging signal indicating the arrival of a signal in the non-NES cell while performing the processes of receiving an MIB, transmitting a WUS, and receiving an SIB1 in the NES cell. That is, the terminal device 141 can receive a paging signal in the NES cell (i.e., DCI format 1_0 with CRC scrambled by P-RNTI in the PDCCH) (until the terminal device 141 starts receiving the paging signal), and can continue to monitor the paging signal in the non-NES cell. It should be noted that P-RNTI is an abbreviation for Paging-RNTI. For this reason, adjustments can be made on the network side so that the transmission and reception timing of the paging signal in the non-NES cell does not overlap with the transmission and reception timing of the MIB and SIB in the NES cell and the transmission and reception timing of the WUS. This allows the terminal device 141 to receive a paging signal from a non-NES cell, receive an MIB and SIB from an NES cell, and transmit a WUS in parallel. Furthermore, if such timing adjustment is not performed, the terminal device 141 may receive a paging signal from a non-NES cell, or receive an MIB / SIB from an NES cell and transmit a WUS based on a predetermined priority if the timing of any of the signals overlaps. Furthermore, prioritizing paging may be configured in advance for the terminal device 141. For example, within a certain time range, processing with a higher priority may be performed first or may be performed more frequently. Note that information on the predetermined priority may be included in the WUS configuration. Meanwhile, the terminal device 141 may perform parallel processing when the respective timings do not overlap. This allows the terminal device 141 to receive a paging signal from a non-NES cell while performing processing for receiving SIB1 from the NES cell.

[0039] In the 3GPP (registered trademark) protocol, Value Tags are defined for SIB2, SIB3, etc., but not for SIB1. Therefore, to determine whether the SIB1 transmitted by the base station device and the SIB1 held by the terminal device 141 are identical, it is assumed that the respective setting values ​​are compared. In contrast, for example, with the introduction of On-demand SIB1, a new Value Tag for SIB1 may be defined, allowing the terminal device 141 to determine whether the SIB1 has been updated. In this case, the NES cell sets a Value Tag for the SIB1 to be transmitted, and transmits the Value Tag, for example, by including it in an MIB. The terminal device 141 then holds the setting information for SIB1, acquired by, for example, transmitting a WUS, in association with the corresponding Value Tag. Then, when the terminal device 141 subsequently receives the MIB of the NES cell, it can check the Value Tag of SIB1 included in the received MIB and determine whether the value matches the Value Tag of the SIB1 it holds. If the value of the Value Tag of SIB1 included in the MIB matches the value of the Value Tag of the SIB1 it holds, the terminal device 141 can determine not to transmit a WUS and not to receive SIB1 (for example, if the expiration date of the information in SIB1 has not expired). On the other hand, if the value of the Value Tag included in the MIB does not match the value of the Value Tag of the SIB1 it holds, the terminal device 141 can transmit a WUS and reacquire SIB1 (for example, even if the expiration date of the information in SIB1 has not expired). For example, the terminal device 141 may perform such processing when it moves from an NES cell to an out-of-service area or to another cell and then moves back within the range of the NES cell. Note that the value of the Value Tag of SIB1 may be included in a message other than the MIB and transmitted. For example, information on the Value Tag of SIB1 may be included in the WUS configuration.In this case, the terminal device 141 may compare the value of the Value Tag of the SIB1 received in the WUS configuration with the Value Tag of the SIB1 that it holds, and determine whether or not it is necessary to transmit a WUS.

[0040] The above-described features may be used in any combination unless there is a contradiction.

[0041] (Device Configuration) FIG. 6 shows an example of the hardware configuration of a base station device (at least one of the base station device 101, the base station device 121, and the base station device 122) and a terminal device 141 according to this embodiment. In one example, the base station device and the terminal device include a processor 601, a ROM 602, a RAM 603, a storage device 604, and a communication circuit 605. The processor 601 is a computer including one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and executes the overall control processing of the device and the above-mentioned processes by reading and executing programs stored in the ROM 602 and the storage device 604. The ROM 602 is a read-only memory that stores information such as programs and various parameters related to the processes executed by the base station device and the terminal device. The RAM 603 functions as a workspace when the processor 601 executes a program and is also a random access memory that stores temporary information. The storage device 604 is, for example, a removable external storage device. The communication circuit 605 is configured, for example, with a circuit for wireless communication of LTE, 5G, or a successor standard. While FIG. 6 illustrates one communication circuit 605, the base station apparatus and the terminal apparatus may have multiple communication circuits. For example, the base station apparatus and the terminal apparatus may have wireless communication circuits for LTE, 5G, and a successor standard, respectively, and a common antenna for these circuits. The base station apparatus and the terminal apparatus may also have separate antennas suitable for each standard. The base station apparatus may also have a wired communication circuit used when communicating with other base station apparatuses or core network nodes. The terminal apparatus may also have a communication circuit conforming to a wireless communication standard other than the cellular communication standard, such as a wireless local area network (LAN) or Bluetooth (registered trademark). The base station apparatus and the terminal apparatus may have separate communication circuits 605 for each of multiple available frequency bands, or may have a common communication circuit 605 for at least some of these frequency bands.

[0042] FIG. 7 shows an example of the functional configuration of a terminal device according to this embodiment. The terminal device includes, for example, a setting receiver 701, a WUS transmission controller 702, and an SI acquirer 703. Note that FIG. 7 only shows functions related to this embodiment in a simplified manner, and other functions are omitted. For example, the terminal device naturally has functions generally possessed by a terminal device (User Equipment, UE) in a cellular communication system. The functions shown in FIG. 7 may be implemented, for example, by a processor included in the communication circuit 205 executing instructions stored in memory, or by the processor 201 executing instructions stored in the ROM 202, the storage device 204, or the like to control the communication circuit 205. The functions may also be implemented in the form of a program that causes the terminal device to implement the following functions, or a (non-transitory) storage medium that stores the program. Since the details of the operation of each component are as described above, only an overview of the device configuration will be described here, and detailed description thereof will be omitted.

[0043] The setting receiver 701 receives various setting information such as the WUS configuration and SIB1 reception settings. The WUS transmission controller 702 transmits a WUS based on the WUS configuration. Furthermore, if SIB1 cannot be received after transmitting a WUS, the WUS transmission controller 702 may retransmit the WUS. For example, if an NES cell is selected as the destination cell through cell selection / reselection, the WUS transmission controller 702 may transmit a RAP as a WUS to the base station device of the NES cell. Then, if an RAR cannot be received after transmitting a RAP or if reception of SIB1 fails, the WUS transmission controller 702 retransmits the WUS, or, if necessary, performs processing such as regarding the NES cell as being in a barred state. After transmitting the WUS, for example, in response to receiving an RAR, the SI acquisition unit 703 checks the PDCCH (DCI) corresponding to SIB1 and receives SIB1 based on the DCI. Note that, for example, when the SI acquisition unit 703 determines that the validity period of SIB1 has expired or that SIB1 has been updated, the SI acquisition unit 703 can operate to cause the WUS transmission control unit 702 to transmit a WUS and acquire SIB1.

[0044] FIG. 8 shows an example of the functional configuration of a base station device according to this embodiment. The functional configuration of the base station device shown in FIG. 8 may be implemented in each base station device of an NES cell, or some of the configuration information notification function may be transferred to a non-NES cell. That is, FIG. 8 may be implemented as the functional configuration of a single base station device, or may be distributed across multiple base station devices. The base station device includes, as its functions, a configuration notification unit 801 and an SI notification unit 802. FIG. 8 schematically illustrates only functions related to this embodiment, and omits other functions. For example, the base station device naturally has functions that a base station device (such as a gNodeB) in a cellular communication system typically has. The functions shown in FIG. 8 may be implemented, for example, by a processor included in the communication circuit 205 executing instructions stored in a memory, or by a processor 201 executing instructions stored in the ROM 202, the storage device 204, or the like to control the communication circuit 205. The above functions may also be implemented in the form of a program that causes the terminal device to implement the following functions, or a (non-transitory) storage medium that stores the program. Note that, since the details of the operation of each component are as described above, only an overview of the device configuration will be explained here, and detailed explanations thereof will be omitted.

[0045] The setting notification unit 801 notifies the terminal device of setting information for the terminal device to receive the WUS configuration and SIB1 related to the base station device of the NES cell. For example, the setting notification unit 801 of the base station device of the non-NES cell notifies the terminal device of the WUS configuration via a message such as an SIB. Furthermore, the setting notification unit 801 of the base station device of the NES cell or the non-NES cell can notify the terminal device of the WUS configuration via an RRC Release message or the like when a terminal device in a connected state transitions to a non-connected state. Furthermore, the setting notification unit 801 of the base station device of the NES cell can transmit an MIB including information such as the resource location of the PDCCH (DCI) for receiving the RAR and SIB1. When providing an NES cell, the SI notification unit 802 transmits SIB1 to the terminal device in response to receiving a WUS from the terminal device. For example, when the SI notification unit 802 receives a RAP from the terminal device, the SI notification unit 802 returns an RAR to the terminal device and then transmits SIB1 to the terminal device.

[0046] The terminal device 141 has a function of saving and deleting the WUS configuration. When triggered by cell selection or cell reselection, the terminal device 141 acquires broadcast information of the destination cell, including the WUS configuration, and saves it in an internal memory of the terminal device 141. At this time, the terminal device 141 saves the WUS configuration together with information that can identify the cell from which the WUS configuration was acquired. Here, a method for acquiring the WUS configuration (cell 1) related to WUS that the terminal device 141 transmits to acquire SIB1 in cell 1, which is an NES cell, will be described as an example. The terminal device 141 acquires the WUS configuration (cell 1) from cell 2, which is a non-NES cell. In this case, the terminal device 141 stores information such as information 1: WUS configuration (cell 1), acquired cell = cell 2 in its internal memory. Thereafter, when the terminal device 141 reselects a cell from cell 2 to cell 3, it can acquire the WUS configuration (cell 1) from cell 3, which is a non-NES cell. In this case, in addition to the above-mentioned information 1, information such as information 2: WUS configuration (cell 1), acquired cell = cell 3 is stored in the internal memory of the terminal device 141. Thereafter, when the terminal device 141 performs cell reselection to cell 1 while in the coverage area of ​​cell 3 (during campaign), it transmits a WUS using the WUS configuration (cell 1) stored as information 2. Thereafter, when the terminal device 141 performs cell reselection to cell 1 while present in cell 2 (during campaign on), it transmits a WUS using the WUS configuration (cell 1) stored as information 1. Thereafter, when the terminal device 141 performs cell reselection to cell 1 while present in cell 4 (during campaign on), it is assumed that the terminal device 141 has not acquired the WUS configuration (cell 1) in cell 4 or does not retain this information. In this case, the terminal device 141 may exclude cell 1 from targets for cell reselection for a certain period of time because it does not retain the WUS configuration (cell 1) that should be used when reselecting from cell 4 to cell 1.According to this embodiment, when the terminal device 141 acquires multiple WUS configurations from multiple cells, it is not necessary to integrate the multiple WUS configurations. Note that WUS configurations for a common NES cell received in multiple different cells may be integrated.

[0047] Furthermore, the terminal device 141 can determine whether the stored WUS configuration has been updated based on whether the Value Tag associated with the broadcast information including the WUS configuration has been updated. For example, if the terminal device 141 holds information 1: WUS configuration (cell 1), acquired cell = cell 2, and Value Tag = 1, it is assumed that the terminal device 141 has broadcast information in cell 2 with Value Tag = 2 including the WUS configuration. In this case, the terminal device 141 can determine that the WUS configuration has been updated and re-acquire the WUS configuration. Furthermore, the terminal device 141 may reacquire the WUS configuration upon expiration of a retention timer associated with broadcast information including the WUS configuration. That is, the terminal device 141 may execute a process of reacquiring the WUS configuration in response to expiration of the broadcast information retention period. That is, the terminal device 141 may reacquire the WUS configuration using the above-described Value Tag or retention timer, rather than reacquiring broadcast information (SIB) including the WUS configuration every time a cell is reselected. This allows the terminal device 141 to efficiently reacquire the WUS configuration.

[0048] The terminal device 141 may save / delete / update the WUS configuration on an area-by-area basis. For example, while the terminal device 141 is located in a non-NES cell, the terminal device 141 receives SIB1 or the WUS configuration that includes information (e.g., areascope) indicating whether or not to manage (save / delete / update) the WUS configuration on an area-by-area basis. Note that if the information is not included in SIB1 or the WUS configuration, the terminal device 141 can manage (save / update / delete) the WUS configuration on a cell-by-cell basis. This can simplify the implementation of the base station device. When the terminal device 141 receives information indicating whether or not to manage the WUS configuration on an area-by-area basis, the terminal device 141 compares information that enables it to determine whether the retained WUS configuration has been updated (e.g., systemInformationAreaID, ValueTag, the first PLMN-Identity in PLMN-IdentityInfoList) with the information received via SIB1 or the WUS configuration. If the retained value differs from the received value, the terminal device 141 determines that the retained WUS configuration is old information and may update the WUS configuration. Furthermore, if the stored value matches the received value, the terminal device 141 determines that the stored WUS configuration information is the latest and does not update the WUS configuration. Note that the above example can be executed, for example, when the terminal device 141 is connected to a base station device 101 of a non-NES cell, or when the terminal device 141 stores a WUS configuration after cell reselection from a non-NES cell formed by the base station device 101 to an NES cell formed by the base station device 102. Furthermore, even when managing the WUS configuration on an area-by-area basis, the terminal device 141 can reacquire the WUS configuration upon expiration of a retention expiration timer associated with broadcast information including the WUS configuration.

[0049] The terminal device 141 may also store / delete / update information of SIB1 (included in SIB1) on an area-by-area basis. The 3GPP (registered trademark) protocol does not stipulate that information of SIB1 be managed (stored / deleted / updated) on an area-by-area basis. Therefore, the base station device transmits SIB1 (to the terminal device 141) including information indicating whether or not information of SIB1 is managed on an area-by-area basis (e.g., areascope). Here, in the information indicating whether or not information of SIB1 is managed on an area-by-area basis, separate values ​​may be defined for SIB1 and other SIBs, such as areascope-SIB1 for SIB1 and areascope for other SIBs. Furthermore, the same parameter value (areascope) may be used for these SIBs. Note that the terminal device 141 may manage SIB1 information on a cell-by-cell basis if it does not receive such information, such as if it receives SIB1 that does not include information indicating whether SIB1 information should be managed on an area-by-area basis. When the terminal device 141 receives information indicating that SIB1 information should be managed on an area-by-area basis, the terminal device 141 compares values ​​(e.g., systemInformationAreaID, ValueTag, and the first PLMN-Identity in PLMN-IdentityInfoList defined for SIB1) included in the SIB1 received within the area that enable determination of whether SIB1 has been updated with values ​​previously received and stored by the terminal device 141. Then, if the received value differs from the stored value, the terminal device 141 may determine that the stored SIB1 information is old and update the stored information with the received SIB1 information. Furthermore, if the received value and the stored value are the same, the terminal device 141 may determine that the stored information of SIB1 is the latest and may omit updating the information of SIB1. For example, when the terminal device 141 transitions from an NES cell to an out-of-service area or to another cell and then moves back within the range of the NES cell, the terminal device 141 may execute the above-described process, such as determining whether to update SIB1.Furthermore, even when managing information about SIB1 on an area-by-area basis, the terminal device 141 may reacquire SIB1 upon expiration of a retention time limit timer associated with broadcast information containing SIB1.

[0050] As described above, in a system in which a base station device of an NES cell transmits SIB1 in response to receiving a WUS from a terminal device, the terminal device can efficiently operate to receive SIB1, thereby contributing to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0051] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

[0052] This application claims priority to U.S. Provisional Patent Application No. 63 / 680,400, filed August 7, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A terminal device for a cellular communication system, comprising: a transmitting means for transmitting a random access preamble (RAP) as a wake-up signal (WUS) to a first base station device in the cellular communication system that does not periodically transmit a system information block type 1 (SIB1); and a receiving means for receiving first downlink control information (first DCI) or first physical downlink control information (first PDCCH) for receiving a random access response (RAR), and receiving the RAR using the first DCI or the first PDCCH; and a receiving means for receiving a second DCI or a second PDCCH for receiving SIB1, and receiving the SIB1 using the second DCI or the second PDCCH. A terminal device, wherein the receiving means receives parameters for receiving the first DCI or the first PDCCH or the second DCI or the second PDCCH from a second base station device that periodically transmits SIB1, and the receiving means, when receiving the RAR, receives the second DCI or the second PDCCH and receives the SIB1, and when not receiving the RAR, does not receive the second DCI and the second PDCCH.

2. The terminal device according to claim 1, further comprising a determination means for determining whether reception of the SIB1 was successful, and if it is determined that reception of the SIB1 was unsuccessful, determining that a cell to which the SIB1 is not periodically transmitted is subject to access restriction.

3. The terminal device according to claim 2, wherein the determination means determines that reception of the SIB1 has failed if the SIB1 cannot be received within a predetermined period after transmission of the WUS or reception of the RAR.

4. The terminal device described in claim 2, wherein the transmitting means retransmits the WUS if the RAR is not received after transmitting the WUS, and the determining means determines that reception of the SIB1 has failed if the RAR is not received even after the number of retransmissions of the WUS reaches the maximum number of retransmissions notified in advance in the WUS settings.

5. The terminal device according to claim 1, further comprising an acquisition means for acquiring the WUS configuration for one or more cells in which the SIB1 is not periodically transmitted.

6. The terminal device according to claim 5, wherein the acquisition means acquires a first list indicating each of the one or more cells and a second list indicating one or more WUS settings to be applied to each of the one or more cells.

7. The terminal device according to claim 6, wherein in the first list, an index is assigned to each of the one or more cells, and in the second list, information indicating which of the one or more WUS settings is applied to each of the one or more cells is indicated using the index in the first list.

8. The terminal device of claim 6, wherein the first list includes a physical cell identifier for each of the one or more cells.

9. The terminal device according to claim 5, wherein said acquisition means further acquires information indicating whether said WUS setting is valid.

10. A terminal device as described in claim 5, wherein the WUS setting includes information indicating a window in which reception processing of the SIB1 should be performed, and the receiving means, when receiving the RAR, performs reception processing of the SIB1 during the time period of the window.

11. The terminal device according to claim 10, wherein said transmitting means retransmits said WUS if said SIB1 cannot be received within said window time period.

12. The terminal device described in claim 5, wherein the WUS setting includes information indicating a window in which the RAR reception processing is performed after the WUS is transmitted, and the receiving means performs the RAR reception processing during the time period of the window after the WUS is transmitted.

13. The terminal device according to claim 5, wherein the acquisition means acquires the WUS settings from the second base station device.

14. The terminal device according to claim 5, wherein said acquisition means acquires said WUS settings from said first base station device.

15. The terminal device according to claim 5, wherein, after transmitting the WUS, when it is determined that a cell is reselected to a cell other than a cell that does not periodically transmit the SIB1 to be transmitted, the WUS transmission process is terminated.

16. A control method executed by a terminal device in a cellular communication system, comprising: transmitting a random access preamble (RAP) as a wake-up signal (WUS) to a first base station device in the cellular communication system that does not periodically transmit a system information block type 1 (SIB1); receiving first downlink control information (first DCI) or first physical downlink control information (first PDCCH) for receiving a random access response (RAR), and performing a process of receiving the RAR using the first DCI or the first PDCCH; and receiving a second DCI or a second PDCCH for receiving the SIB1, and performing a process of receiving the SIB1 using the second DCI or the second PDCCH. A control method comprising: receiving parameters for receiving the first DCI or the first PDCCH, or the second DCI or the second PDCCH, from a second base station device that periodically transmits SIB1; receiving the second DCI or the second PDCCH and receiving the SIB1 when the RAR is received; and not receiving the second DCI and the second PDCCH when the RAR is not received.

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