Terminal device, base station device, control method for terminal device, and control method for base station device

Abstract

This terminal device includes a transmitting unit, a receiving unit, and a control unit. The transmitting unit communicates with a first base station device and a second base station device, and transmits, to the second base station device, a request signal for requesting essential system information from the second base station device, on the basis of setting information for the request signal, acquired from the first base station device. The receiving unit receives the essential system information transmitted from the second base station device in response to the request signal. When transmitting the request signal to the second base station device, the control unit controls the transmission power by applying a maximum transmission power value determined on the basis of transmission power control information acquired from the first base station device. The transmission power control information is divided into first transmission power control information that is not associated with the setting information of the second base station device and second transmission power control information that is associated with the second base station device, and the maximum transmission power value is determined using the first transmission power control information for the first base station device and using the second transmission power control information for the second base station device.

Description

Terminal device, base station device, terminal device control method, and base station device control method

[0001] The present invention relates to a terminal device, a base station device, a method for controlling a terminal device, and a method for controlling a base station device.

[0002] In today's networks, traffic from mobile devices (such as smartphones and feature phones) accounts for the majority of network resources, and traffic from mobile devices is expected to continue to grow.

[0003] In addition to traffic used by mobile terminals, for example, IoT (Internet of Things) services (for example, monitoring systems for transportation systems, smart meters, and devices) are being deployed. Therefore, networks are required to support services with diverse requirements. In order to support such diverse services, for example, the communication standard for fifth-generation mobile communications (5G or NR (New Radio)) is designed to support many use cases classified as eMBB (Enhanced Mobile Broadband), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications).

[0004] In addition, in the 3rd Generation Partnership Project (3GPP), an international standardization project, extension technologies for the above communication standards are currently being continuously studied and standardized.

[0005] In 3GPP, NES (Network Energy Savings) technology is being studied to reduce power consumption on the network side (i.e., base station devices, core network devices) (Non-Patent Document 1). Hereinafter, a cell (base station device) corresponding to the NES function, i.e., a cell supporting the NES function, is also referred to as an NES cell.

[0006] 3GPP TR 38.864 V18.0.0 (2022-12) R1-2405106

[0007] Generally, a base station device broadcasts system information within a cell as information commonly used by terminal devices within the cell. The system information is also referred to as broadcast information. In 3GPP, as one of the network power reduction technologies, a method is being considered for reducing the power consumption of a base station device by introducing an on-demand SIB1 that is appropriately transmitted (on-demand transmitted) from an NES cell in response to a request from a terminal device, instead of SIB1 (System Information Block Type 1), which is a type of broadcast information that is periodically transmitted. For example, Non-Patent Document 2 discloses an example of parameter information applied to an uplink wake-up signal (UL-WUS) procedure used in a terminal device to request an on-demand SIB1.

[0008] However, in conventional communication systems, the cell's transmission power control information is included in SIB1 and other SIBs. Therefore, in the case of On-demand SIB1, which is transmitted as appropriate in response to a request from a terminal device, uplink transmission to the NES cell occurs before the terminal device acquires the transmission power control information. Therefore, until receiving On-demand SIB1, the terminal device cannot determine whether the transmission power value applied to the uplink transmission is less than the maximum value for the cell, resulting in a problem of transmitting to the base station device at a transmission power value exceeding the upper limit. Furthermore, since the base station device cannot notify in advance by SIB1 whether transmission power is restricted, it cannot prevent the terminal device from transmitting on the uplink at a transmission power value exceeding the maximum value, resulting in a problem of being unable to control an increase in uplink interference within the cell. However, non-patent document 2 does not mention any solutions to these problems.

[0009] An object of one aspect of the present invention is to appropriately implement transmission power control related to wireless communication between a terminal device and a base station device when applying a network power reduction technique that appropriately transmits system information (SIB1).

[0010] A terminal device according to one aspect of the present invention is a terminal device capable of communicating with a first base station device and a second base station device, and is equipped with a transmitter that transmits a request signal to the second base station device based on configuration information of the request signal, which is acquired from the first base station device, requesting essential system information of the second base station device; a receiver that receives the essential system information of the second base station device transmitted in response to the request signal; and a control unit that controls the transmission power by applying a maximum transmission power value determined based on transmission power control information acquired from the first base station device when transmitting the request signal to the second base station device, wherein the transmission power control information is divided into first transmission power control information that is not associated with the configuration information of the second base station device and second transmission power control information that is associated with the second base station device, and the first transmission power control information is used for the first base station device, and the second transmission power control information is used for the second base station device to determine the maximum transmission power value.

[0011] A base station device according to one aspect of the present invention is a base station device in a communication system including a first cell that periodically transmits essential system information and a second cell that transmits the essential system information in response to a request from a terminal device, and includes: a receiving unit that receives configuration information of a request signal for the essential system information of the second cell used by the terminal device; a transmitting unit that transmits the configuration information of the request signal, first transmission power control information that is not associated with configuration information regarding the second cell, and second transmission power control information associated with the second cell to the terminal device using the first cell; and a control unit that sets the first transmission power control information to the terminal device to determine the maximum transmission power of the first base station device, and sets the second transmission power control information to determine the maximum transmission power of the second base station device.

[0012] According to the above-described aspect, when applying a network power reduction technique, transmission power control related to wireless communication between a terminal device and a base station device is appropriately performed.

[0013] Fig. 1 is a diagram showing an example of the configuration of a wireless communication system according to an embodiment. Fig. 2 is a diagram showing an example of the functional configuration of a terminal device according to an embodiment. Fig. 3 is a diagram showing an example of the functional configuration of a base station device according to an embodiment. Fig. 4 is a diagram showing an example of an On-demand SIB1 procedure. Fig. 5 is a flowchart showing an example of a method for determining transmission power control information to be applied. Fig. 6 is a diagram showing an example of the hardware configuration of a terminal device. Fig. 7 is a diagram showing an example of the hardware configuration of a base station device.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The problems and embodiments in this specification are merely examples and do not limit the scope of the present invention. In particular, even if the expressions used are different, the technology of the present invention can be applied as long as they are technically equivalent, and do not limit the scope of the present invention. Furthermore, each embodiment can be appropriately combined within the scope of the processing content. For example, an inactive period may be referred to as an inactive period.

[0015] Publicly known technologies may be used as appropriate in the wireless communication system according to the embodiment of the present invention. Applicable publicly known technologies may be, for example, 5G (NR), Beyond 5G, 5G-Advanced, or other wireless communication methods. The wireless communication system according to the embodiment of the present invention targets NR, but is not limited thereto. For example, the embodiment of the present invention can also be applied to LTE (Long Term Evolution) and LTE-Advanced. It can also be applied to a wireless communication system that uses NR as part of the wireless communication system.

[0016] Furthermore, the embodiments of the present invention are applicable to any wireless communication system including at least a terminal device and a base station device, and are also applicable to future wireless communication systems. In the following description, LTE and LTE-Advanced are also referred to as E-UTRA (Evolved Universal Terrestrial Radio Access), but the meaning is the same.

[0017] Hereinafter, embodiments of a base station apparatus, a terminal apparatus, and a wireless communication system disclosed in the present application will be described with reference to the drawings. Note that the disclosed technology is not limited to the following embodiments.

[0018] <Wireless Communication System> FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system 1 according to an embodiment of the present invention. The wireless communication system 1 according to the embodiment includes, for example, a terminal device 10, base station devices 20A and 20B, and a core network 30. The wireless communication system 1 is, for example, a wireless communication system compatible with NES, in other words, a wireless communication system that supports the NES function. The base station device 20A is a base station device 20 (first base station device) that transmits information for accessing the base station device 20B that supports the NES function. On the other hand, the base station device 20B is a base station device 20 (second base station device) that also supports the NES function, and access is attempted based on information from the base station device 20A. Note that when there is no need to distinguish between the base station devices 20A and 20B, they are simply referred to as the base station device 20. Furthermore, there may be multiple terminal devices 10.

[0019] The terminal device 10 may be a wireless terminal such as a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a tablet, a wearable device, a personal computer, a vehicle, or any other device or equipment (sensor device, etc.) having a wireless communication function. The terminal device 10 may also be referred to as a wireless communication device, a communication device, a receiving device, a mobile station, a UE (User Equipment), a user device, etc.

[0020] A wireless communication service is provided to a terminal device 10 by a base station device 20 and a core network 30 in a wireless communication system 1. The core network 30 has functions such as managing service subscriber information, managing sessions such as voice calls, and managing location registration of the terminal device 10. The core network 30 also transmits control data and / or user data to the terminal device 10 via the base station device 20.

[0021] The core network 30 may be a 5G Core (5GC) in 5G (NR) or an Evolved Packet Core (EPC) in 4G (E-UTRA). The connection method between the core network 30 and the base station device 20 may be a Non-Stand Alone (NSA) method or a Stand Alone (SA) method.

[0022] The 5G base station device 20 connected to the 5GC is a gNB, and the 4G base station device 20 connected to the EPC is an eNB. The 5G base station devices are physically or logically connected via an Xn interface. Similarly, the 4G base station devices are physically or logically connected via an X2 interface.

[0023] An area (coverage area) formed by a base station device 20 may be called a "cell." E-UTRA and 5G are cellular communication systems constructed by multiple cells. As a wireless communication system according to an embodiment of the present invention, either a time division duplex (TDD) or a frequency division duplex (FDD) method may be applied, and different methods may be applied to each cell.

[0024] Hereinafter, the cell configured by the base station device 20A is also referred to as a normal cell 20A-1 (first cell). The normal cell 20A-1 is, for example, a cell that does not support NES or an NES cell (described later) that does not apply power saving technology. Furthermore, a cell configured by the base station device 20B that can transition to a state (sleep state) in which power consumption can be reduced by applying a predetermined power saving technology is also referred to as a NES cell 20B-1 (second cell). For example, in the sleep state, the NES cell 20B-1 achieves power saving by halting transmission and reception of signals other than predetermined physical signals and physical channels and shutting down standby power for wireless devices within the base station device 20B. The predetermined physical signals and physical channels are, for example, the PDCCH and PDSCH related to the On-demand SIB1.

[0025] The normal cell 20A-1 is an anchor cell for providing (transferring, notifying) information necessary for the terminal device 10 to access the NES cell 20B-1 to the terminal device 10. In addition, the NES cell 20B-1 provides the normal cell 20A-1 with at least control information used to determine whether the terminal device 10 can access the NES cell 20B-1, and UL-WUS setting information (described later) for requesting an On-demand SIB1 from the NES cell 20B-1.

[0026] 1 illustrates a correspondence relationship in which the normal cell 20A-1 includes the NES cell 20B-1, but the size and positional relationship of these two cells is merely an example, and a correspondence relationship other than that shown in FIG. 1 may be used. For example, the normal cell 20A-1 and the NES cell 20B-1 may be the same size, or the NES cell 20B-1 may be larger. A configuration in which the normal cell 20A-1 includes multiple NES cells 20B-1 may also be used.

[0027] The sleep state is, for example, a state in which some of the functions related to transmission and reception of the base station device 20B (NES cell 20B-1) are stopped, and at the same time, power supply to internal devices related to transmission and reception is suppressed, and at least one of transmission and reception of some messages transmitted by the base station device 20B and corresponding physical signals and physical channels is not performed. Furthermore, for example, when the sleep state is released (application of a predetermined power saving technology is stopped) or when the sleep state is temporarily released, the NES cell 20B-1 enters a non-sleep state and transitions to a cell (for example, the normal cell 20A-1) in which normal wireless communication can be performed.

[0028] The terminal device 10 is a communication device that is wirelessly connected to the base station device 20A or the base station device 20B and transmits and receives data. The terminal device 10 is also a communication device that corresponds to the NES function, i.e., a communication device that supports the NES function.

[0029] The NES cell may include, for example, a base station device 20B that is transitioning to a sleep state and a base station device 20B that may transition to a sleep state. Furthermore, the normal cell 20A-1 and the NES cell 20B-1 may be cells under the control of the same base station device 20 or may be cells under the control of different base station devices 20.

[0030] The base station device 20 may be configured, for example, as being divided into a CU (Centralized Unit), a DU (Distributed Unit), and an RU (Radio Unit). The CU is connected to a core network. The DU is connected to the terminal device 10 via the RU, for example. The communication path between the CU and the DU is realized by, for example, a fronthaul interface (F1 interface). Multiple DUs may be connected to one CU.

[0031] In the example shown in Figure 1, data (DL data, downlink data) transmitted from the core network 30 to the terminal device 10 is transmitted from the core network 30 to the base station device 20, and then transmitted (forwarded) from the base station device 20 to the terminal device 10.

[0032] Data (UL data, uplink data) transmitted from the terminal device 10 to the core network 30 is transmitted from the terminal device 10 to the base station device 20 and then transmitted (transferred) from the base station device 20 to the core network 30 .

[0033] The terminal device 10 and the base station device 20 transmit and receive RRC messages (also called RRC signaling) in a Radio Resource Control (RRC) layer. Also, the terminal device 10 and the base station device 20 transmit and receive MAC control elements (MAC CEs) in a Medium Access Control (MAC) layer.

[0034] The RRC message is transmitted as an RRC Protocol Data Unit (PDU), and the logical channel (LCH) to which it is mapped may be a common control channel (CCCH), a dedicated control channel (DCCH), a paging control channel (PCCH), a broadcast control channel (BCCH), or a multicast control channel (MCCH).

[0035] The MAC CE is transmitted as a MAC PDU (or MAC subPDU). A MAC subPDU is equivalent to a service data unit (SDU) in the MAC layer plus, for example, 8 bits of header information, and the MAC PDU includes one or more MAC subPDUs.

[0036] Next, as physical channels and physical signals related to the embodiment, there are at least a synchronization signal (Primary Synchronization Signal, Secondary Synchronization Signal), a physical broadcast channel (PBCH: Physical Broadcast Channel), a physical random access channel (PRACH: Physical Random Access Channel), a physical downlink control channel (PDCCH: Physical Downlink Control Channel), a channel state information reference signal (CSI-RS: Channel State Information-Reference Signal), a physical uplink control channel (PUCCH: Physical Uplink Control Channel), a physical downlink shared channel (PDSCH: Physical Downlink Shared Channel), a physical uplink shared channel (PUSCH: Physical Uplink Shared Channel), a scheduling reference signal (SRS: Scheduling Reference Signal), and a demodulation reference signal (DMRS), but detailed description thereof will be omitted.

[0037] <Terminal Device> Fig. 2 is a diagram showing an example of the functional configuration of a terminal device 10 according to an embodiment. As shown in Fig. 2, the terminal device 10 includes, for example, a processing unit 11, a control unit 13, a receiving unit 15, a transmitting unit 17, and a transmitting / receiving antenna unit 19. The processing unit 11 includes, for example, a radio resource processing unit 111 and a control processing unit 113. Note that the functional configuration of the terminal device 10 shown in Fig. 2 is merely an example, and the functional divisions and names of each functional block may be different as long as the operations according to the embodiment can be performed. Furthermore, one or more blocks that realize other functions may be present.

[0038] The processing unit 11 generates, for example, control information for controlling the receiving unit 15 and the transmitting unit 17, and outputs the control information to the control unit 13. The processing unit 11 executes processes related to, for example, a radio resource control layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control layer.

[0039] The radio resource processing unit 111 manages various setting information (RRC parameters, information elements (IEs)) of the terminal device 10. For example, the radio resource processing unit 111 generates information to be allocated to each channel of the physical uplink and outputs the information to the transmission unit 17. Furthermore, based on instructions from the base station device 20, the radio resource processing unit 111 performs measurements of the serving cell and surrounding cells, start and stop of transmission and reception processing, DL synchronization procedure (cell search), UL synchronization procedure (random access procedure), UL-WUS transmission procedure, acquisition and reacquisition of system information, event evaluation related to handover, a series of processes related to handover, and the like.

[0040] The control processing unit 113 acquires, classifies, and interprets information related to access restrictions, and executes control processing to determine whether or not the cell is accessible based on the type, supported functions, etc. of the terminal device 10. The control processing unit 113 also executes control processing to determine the setting value of the transmission power (maximum transmission power) to be applied during UL-WUS transmission. The control processing unit 113 also executes control processing to determine whether or not UL-WUS transmission is necessary, based on instructions from the radio resource processing unit 111 or instructions from the base station device 20.

[0041] The control unit 13 performs various controls in the terminal device 10. For example, the control unit 13 generates control signals or control data for controlling the receiving unit 15 and the transmitting unit 17 based on control information from the processing unit 11. Furthermore, the control unit 13 controls uplink transmission to the base station device 20, scheduling request transmission, UL-WUS transmission, and downlink reception from the base station device 20 based on determination information related to transmission control from the control processing unit 113.

[0042] The receiving unit 15 separates, demodulates, and decodes various signals received from the base station device 20 via the transmitting / receiving antenna unit 19 based on a control signal provided by the control unit 13. The receiving unit 15 outputs the decoded information to the processing unit 11.

[0043] The transmitter 17 generates, for example, a physical uplink signal based on a control signal provided from the controller 13, and performs encoding and modulation on the physical uplink signal or the physical uplink channel provided from the processor 11. The transmitter 17 multiplexes various signals and transmits them to the base station device 20 via the transmitter-receiver antenna unit 19.

[0044] The processing unit 11 and the control unit 13 are realized, for example, by a processor system including a processor and a memory. In this case, the processor provides the functions of the processing unit 11 and the control unit 13 by executing a program that describes the operation of the terminal device 10, which will be described later. The processing unit 11 and the control unit 13 may be realized by a single processor system or by multiple processor systems. Alternatively, the processing unit 11 and the control unit 13 may be realized by a DSP (Digital Signal Processor), a hardware circuit, or the like.

[0045] <Base Station Device> Fig. 3 is a diagram illustrating an example of the functional configuration of a base station device 20 according to an embodiment. As illustrated in Fig. 3, the base station device 20 includes, for example, a processing unit 21, a control unit 23, a receiving unit 25, a transmitting unit 27, and a transmitting / receiving antenna unit 29. The processing unit 21 illustratively includes a radio resource processing unit 211 and an SIB1 control processing unit 213. Note that the functional configuration of the base station device 20 illustrated in Fig. 3 is merely an example, and the names of the functional divisions and functional blocks may be different as long as the operations according to the embodiment can be performed. Furthermore, one or more blocks that realize other functions may be present.

[0046] The processing unit 21 generates, for example, control information for controlling the receiving unit 25 and the transmitting unit 27, and outputs the control information to the control unit 23. The processing unit 21 executes processes relating to, for example, the radio resource control layer, the packet data integration protocol layer, the radio link control layer, and the medium access control layer.

[0047] The radio resource processing unit 211 generates, for example, downlink data, an RRC message, and a MAC control element to be allocated to the physical downlink shared channel PDSCH, and outputs these to the transmission unit 27. The radio resource processing unit 211 also generates a control signal or control data to be allocated to the physical downlink control channel PDCCH, and outputs this to the transmission unit 27. Furthermore, the radio resource processing unit 211 manages various setting information of the terminal device 10. Based on a signal from the terminal device 10 or a notification by an RRC message, the radio resource processing unit 211 executes operations such as starting and stopping transmission and reception processing, starting a UL synchronization procedure (random access procedure), updating system information, starting and stopping on-demand SIB1 transmission, adjusting the beam transmission angle, and generating parameters related to the UL-WUS transmission procedure.

[0048] The SIB1 control processing unit 213 performs a series of control processes related to on-demand SIB1 transmission. For example, the SIB1 control processing unit 213 executes a control process to determine whether on-demand SIB1 transmission is necessary based on an instruction from an upper layer or on reception of an UL-WUS transmitted from the terminal device 10.

[0049] The control unit 23 performs various controls in the base station device 20. For example, the control unit 23 generates a control signal or control data for controlling the receiving unit 25 and the transmitting unit 27 based on control information from the processing unit 21. Furthermore, the control unit 23 controls downlink transmission corresponding to the On-demand SIB1 to the terminal device 10 based on determination information related to the On-demand SIB1 transmission from the SIB1 control processing unit 213.

[0050] The receiving unit 25 separates, demodulates, and decodes various signals received from the terminal device 10 or the core network 30 via the transmitting / receiving antenna unit 29 based on a control signal provided by the control unit 23. The receiving unit 25 outputs the decoded information to the processing unit 21.

[0051] The transmitter 27 generates, for example, a downlink reference signal based on the control signal provided by the controller 23. The transmitter 27 encodes, modulates, multiplexes, and so on various pieces of information provided by the processor 21, and transmits the signal to the terminal device 10 via the transmitting / receiving antenna 29.

[0052] Furthermore, the transmitter 27 transmits data to the terminal device 10, another base station device 20, or the core network 30. The receiver 25 receives data from the terminal device 10, another base station device 20, or the core network 30.

[0053] The processing unit 21 and the control unit 23 are realized, for example, by a processor system including a processor and a memory. In this case, the processor provides the functions of the processing unit 21 and the control unit 23 by executing a program that describes the operation of the base station device 20, which will be described later. The processing unit 21 and the control unit 23 may be realized by a single processor system or by multiple processor systems. Alternatively, the processing unit 21 and the control unit 23 may be realized by a DSP, a hardware circuit, or the like.

[0054] <On-demand SIB1> On-demand SIB1 is one of the power saving technologies applied to the base station device 20, and is a method of appropriately transmitting SIB1, which is one piece of periodically transmitted broadcast information, based on a request from the terminal device 10. The content included in On-demand SIB1 includes at least the setting information (radio connection information (cell common resource information, cell selection criteria information, access restriction information, etc.)) notified in the conventional SIB1, and may further include UL-WUS setting information indicating the transmission setting of UL-WUS, which is a signal for requesting On-demand SIB1. The base station device 20B may be configured to transmit system information other than the on-demand SIB1 (SIB2 (System Information Block Type 2), SIB3 (System Information Block Type 3), ...) on demand in the same manner.

[0055] To receive the on-demand SIB1 of the base station device 20B (NES cell 20B-1), the terminal device 10 detects and acquires the synchronization signal / physical broadcast channel block (SSB) of the base station device 20B and adjusts downlink synchronization using the SSB. The SSB includes a synchronization signal and a physical broadcast channel (PBCH). The synchronization signal is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS).

[0056] Next, the terminal device 10 acquires PDCCH transmission resource information, SSB subcarrier offset information (ssb-Subcarrier Offset), etc. acquired from the MIB (Master Information Block) transmitted in the SSB (PBCH). Then, the terminal device 10 monitors the PDCCH in the acquired transmission resource and acquires the PDSCH (On-demand SIB1) indicated by the DCI of the detected PDCCH. The MIB and SIB1 (On-demand SIB1) are essential system information (Essential System Information). Furthermore, the MIB and SIB1 (On-demand SIB1) may be described as first system information. Furthermore, system information other than the MIB and SIB1 (On-demand SIB1) (for example, SIB2) may be described as second system information.

[0057] The terminal device 10 also calculates cell quality (reception quality) for each cell by measuring SSB or a channel state information reference signal (CSI-RS). The cell quality can be expressed using any of RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), RSSI (Received Signal Strength Indicator), SINR (Signal to Interference plus Noise Ratio), and path loss.

[0058] <UL-WUS Setting Information> The UL-WUS setting information includes some or all of the following information: cell information identifying a cell transmitting UL-WUS (such as a physical cell identifier (PCI) and downlink frequency information); information related to UL-WUS transmission (such as PRACH resource information, SSB reception power threshold, TDD UL / DL slot setting, and uplink frequency); information related to SIB1 reception (such as SSB subcarrier offset information and PDCCH resource information); and information related to PRACH response reception (such as a reception window length and reception start offset information). The terminal device 10 may further include cell selection criteria information (such as an RSRP threshold and a cell-specific offset value). Based on the cell information, the terminal device 10 may determine whether the base station device 20 is a normal cell 20A-1 or a NES cell 20B-1.

[0059] <Transmission Power Control Information> The transmission power control information notified in the system information is used to determine whether a cell is available for cell selection or cell reselection and to determine the maximum value of the transmission power value (maximum transmission power) for uplink transmission in the camped-on cell. Information indicating the transmission power control information is typically Pmax (p-Max), AdditionalSpectrumEmission (Network signaling value), and additionalPmax.

[0060] Pmax is a parameter indicating the upper limit of the maximum transmission power in the cell. AdditionalSpectrumEmission is a parameter indicating the presence of additional regulations for reducing uplink interference with communication systems operating in adjacent frequencies. Furthermore, instead of specifying a specific power value, AdditionalSpectrumEmission is notified by the base station device 20 of an NS value (network signal value). More specifically, the NS value is an index value assigned to a frequency band that requires regulation of the maximum transmission power value depending on the channel bandwidth and number of resource blocks used, and is a value for notifying regulation information related to the transmission power applied to that frequency band.

[0061] When the base station device 20 notifies the NS value in the system information, the terminal device 10 determines that it is necessary to further reduce the applied transmission power. When the NS value is notified, the transmission power value to be actually reduced is defined in advance as "A-MPR (Additional-Maximum Power Reduction)." additionalPmax is a parameter indicating the upper limit of the maximum transmission power to be applied in the cell for which the NS value is notified.

[0062] The base station device 20 sets one or more NS values ​​in list format for a frequency band. When one or more NS values ​​are set for a supported frequency band, the terminal device 10 extracts applicable NS values ​​in the order of the list and applies the NS value with the highest priority. Here, the NS values ​​are listed and notified in order of priority from the perspective of system protection, so when applicable NS values ​​are extracted from the list, the NS value extracted earliest from the list (i.e., the first supported NS value) is applied to the frequency band.

[0063] The transmission power control information is also used as a criterion for cell selection (cell reselection). In cell selection (cell reselection), a value for compensating (correcting) the transmission power value is defined as "Pcompensation." Pcompensation is a value applied to adjust the cell area in consideration of the fact that even if the downlink reception quality of a cell is good, uplink transmissions may not reach the base station device 20 if the transmission power is suppressed. Pcompensation is calculated, for example, using Equation 1.

[0064] (Formula 1) Pcompensation = max(P EMAX1 -P PowerClass , 0) - (min(P EMAX2 , P PowerClass ) - min(P EMAX1 , P PowerClass )

[0065] P EMAX1 corresponds to the value notified by Pmax, and P EMAX2 corresponds to the value of additionalPmax in the cell to which AdditionalSpectrumEmission (NS value) is applied. P PowerClass is a value indicating the power class of the terminal device 10, and is the maximum transmission power that is predefined depending on the type of the terminal device 10. For example, for a normal handheld terminal, the power class is "3" and the maximum transmission power is specified as 23 dBm.

[0066] Taking the above into consideration, the following embodiments of the present invention will be described with reference to the drawings. In the description of the embodiments of the present invention, if a specific description of well-known functions or configurations related to the embodiments of the present invention makes the gist of the embodiments of the present invention unclear, the detailed description will be omitted.

[0067] First Embodiment FIG. 4 is an example of a sequence diagram showing an On-demand SIB1 procedure between a terminal device 10 and a base station device 20 according to a first embodiment.

[0068] The terminal device 10 in Fig. 4 is a terminal device 10 that supports the NES function, and the base station device 20A (normal cell 20A-1) provides configuration information (NES cell access information) required for the terminal device 10 to request an On-demand SIB1 from the NES cell. The method by which the base station device 20A provides the configuration information to the terminal device 10 may involve including the information in system information and transmitting it periodically or on-demand within the cell, or notifying the information using an individual RRC message. The individual RRC message is, for example, an RRCReconfiguration message or an RRCRelease message.

[0069] 4 transmits On-demand SIB1 when it receives UL-WUS from the terminal device 10 or when it determines that the base station device 20B is necessary (for example, when the contents of SIB1 are updated). Similarly, when it determines that the base station device 20B is not necessary (for example, when a predetermined time has passed since the transmission of SIB1), it stops transmitting On-demand SIB1.

[0070] The base station device 20B provides the base station device 20A with NES cell access information via a transmission path between the base station devices 20 (step S100). The NES cell access information includes at least NES cell information (e.g., a combination of a physical cell identifier (PID) and downlink frequency information) that uniquely identifies the NES cell, and setting information related to UL-WUS (UL-WUS setting information).

[0071] The base station device 20B may further include in the NES cell access information a list indicating the NS values ​​for each frequency band supported by the NES cell, additional transmission power values ​​(additionalPmax) corresponding to the NS values, and / or a common transmission power value (Pmax). The base station device 20A transmits (transfers, notifies) to the cell, the NES cell access information including at least one piece of NES cell access information that is accessible from the base station device 20A and received from the base station device 20B (step S101). The terminal device 10 performs a process related to determining whether to transmit UL-WUS to the base station device 20B (NES cell 20B-1) using the NES cell access information received from the base station device 20A, and a process related to setting the transmission power (step S102).

[0072] The base station device 20A transmits, in system information (e.g., SIB1, SIB2, SIB4), a list indicating the NS values ​​for each frequency band supported by the base station device 20A, additional transmission power values ​​(additionalPmax) corresponding to the NS values, and / or a common transmission power value (Pmax). SIB1 notifies common information about serving cells, and each transmission power value transmitted in SIB1 is used to determine whether or not a cell is available for camping on during cell selection. SIB2 notifies information about cell reselection, and each transmission power value transmitted in SIB2 is used to determine whether or not a cell is available for camping on during cell reselection in an intra-frequency band. SIB4 notifies information about inter-frequency cell reselection, and each transmission power value transmitted in SIB4 is used to determine whether or not a cell is available for camping on during cell reselection in an inter-frequency band.

[0073] While camped on the base station device 20A (normal cell 20A-1), the terminal device 10 acquires SIB1, SIB2, and SIB4 of the base station device 20A (normal cell 20A-1).

[0074] Furthermore, the base station device 20A may set and transmit, in the UL-WUS setting information, a list indicating the NS values ​​for each frequency band supported by the base station device 20B and additional transmission power values ​​(additionalPmax) corresponding to the NS values, and / or a common transmission power value (Pmax). The base station device 20A may notify the NS values ​​for each PLMN (Public Land Mobile Network).

[0075] In this way, the terminal device 10 receives from the base station device 20A transmission power control information (first transmission power control information) that is not associated with the cell of the base station device 20B, and transmission power control information (second transmission power control information) that is associated with the cell of the base station device 20B by being set in the UL-WUS setting information.

[0076] Here, the terminal device 10 compares the reception quality of the base station device 20A (normal cell 20A-1), which is the serving cell, with the reception quality of one or more base station devices 20B (NES cell 20B-1), which are cell reselection (cell reselection) candidates, and performs an access judgment on whether to transmit UL-WUS to the cell with the best reception quality. Note that if the terminal device 10 has not been notified (or does not hold) the same NES cell information as the cell detected by cell search, the terminal device 10 does not need to consider the detected cell as a target cell for cell reselection. Also, the terminal device 10 may consider the NES cell 20B-1 as a cell reselection candidate only when the moving speed of the terminal device 10 itself is low.

[0077] The process related to the access determination of the terminal device 10 in step S102 will be described. The terminal device 10 determines whether it is possible to access the base station device 20B based on the NES cell access information acquired in step S101. In other words, the terminal device 10 uses the NES cell access information to determine whether the base station device 20B is a suitable cell for cell reselection. More specifically, the terminal device 10 determines whether it is possible to access the base station device 20B based on the transmission power control information included in the NES cell access information. Note that the transmission power control information and the UL-WUS setting information may be in a format in which a link with the corresponding NES cell information is notified, or in which the transmission power control information is notified as part of the UL-WUS setting information.

[0078] Figure 5 is an example of a flowchart diagram for the terminal device 10 to decide which value to apply from multiple pieces of transmission power control information obtained from the base station device 20A when determining (evaluating) whether the NES cell satisfies the cell reselection criteria.

[0079] The terminal device 10 determines whether the detected cell is an NES cell (step S01). For example, a cell whose downlink frequency matches the PCI specified in the cell information of the UL-WUS setting information is determined to be an NES cell. If the detected cell is not an NES cell (No in step S01), the terminal device 10 determines to perform first power control (transmission power control). On the other hand, if the detected cell is an NES cell (Yes in step S01), the terminal device 10 checks whether the corresponding UL-WUS setting information includes an NS value (step S02).

[0080] If the NS value has been notified as part of the UL-WUS setting information (Yes in step S02), the terminal device 10 determines to perform second power control (transmission power control). On the other hand, if the NS value has not been notified as part of the UL-WUS setting information (No in step S02), the terminal device 10 checks whether the detected NES cell is on the same frequency as the serving cell (normal cell 20A-1) where it is currently camped, or on a different frequency (step S03).

[0081] If the detected NES cell is a cell using the same frequency as the normal cell 20A-1 (Yes in step S03), the terminal device 10 determines to perform the third power control (transmission power control). On the other hand, if the detected NES cell is a cell using a different frequency from the normal cell 20A-1 (No in step S03), the terminal device 10 determines to perform the fourth power control (transmission power control).

[0082] The terminal device 10 performing the first power control may perform conventional transmission power control, and therefore detailed description thereof will be omitted. For example, the terminal device 10 calculates the cell reselection criterion and the maximum transmission power by appropriately using the transmission power control information notified in the received SIB2 or SIB4.

[0083] The terminal device 10 performing the second power control selects the NS value that is supportable and listed first among multiple NS values ​​corresponding to the frequency band indicated in the corresponding cell information in the UL-WUS configuration information of the NES cell 20B-1. Then, if an additionalPmax corresponding to the selected NS value is set, the terminal device 10 uses the additionalPmax in calculating the cell reselection criterion for the NES cell 20B-1 (that is, applies it to Equation 1). On the other hand, if a corresponding additionalPmax is not set, the terminal device 10 uses the Pmax set in the UL-WUS configuration information in calculating the cell reselection criterion for the NES cell 20B-1.

[0084] Furthermore, if additionalPmax is not set in the UL-WUS setting information, (1) if the frequency bands indicated in the cell information corresponding to the UL-WUS setting information are the same frequency, the Pmax and / or additionalPmax of the SIB2 acquired from the base station device 20A (normal cell 20A-1) is used to calculate the cell reselection criterion for the NES cell 20B-1, or (2) if the frequency bands indicated in the cell information corresponding to the UL-WUS setting information are different frequencies, the corresponding Pmax and / or additionalPmax from the SIB4 acquired from the base station device 20A (normal cell 20A-1) is used to calculate the cell reselection criterion for the NES cell 20B-1. If neither Pmax nor additionalPmax is set in the UL-WUS setting information, the terminal device 10 may consider the maximum transmission power value specified by the power class of the terminal device 10 to be Pmax.

[0085] Furthermore, the terminal device 10 performing the third power control selects the NS value that is supportable and listed first from the multiple NS values ​​indicated in SIB2 acquired from the base station device 20A (normal cell 20A-1). Then, if an additionalPmax corresponding to the selected NS value is set, the terminal device 10 uses the additionalPmax in calculating the cell reselection criterion for the NES cell 20B-1. On the other hand, if a corresponding additionalPmax is not set, the terminal device 10 uses Pmax in SIB2 acquired from the base station device 20A (normal cell 20A-1) in calculating the cell reselection criterion for the NES cell 20B-1. If neither Pmax nor additionalPmax is set in SIB2, the terminal device 10 may regard the maximum transmission power value specified by the power class of the terminal device 10 as Pmax.

[0086] Furthermore, the terminal device 10 performing the fourth power control acquires, from the SIB4 acquired from the base station device 20A (normal cell 20A-1), a plurality of NS values ​​corresponding to the frequency band that matches the cell information included in the UL-WUS setting information of the NES cell 20B-1, and selects, from the plurality of NS values, the NS value that is supportable and that is listed first. Then, if an additional Pmax corresponding to the selected NS value is set, the terminal device 10 uses the additional Pmax in calculating the cell reselection criterion for the NES cell 20B-1. On the other hand, if a corresponding additional Pmax is not set, the terminal device 10 uses the Pmax of the SIB4 acquired from the base station device 20A (normal cell 20A-1) in calculating the cell reselection criterion for the NES cell 20B-1. If neither Pmax nor additionalPmax is set in SIB4, the terminal device 10 may regard the maximum transmission power value defined by the power class of the terminal device 10 as Pmax.

[0087] Furthermore, the terminal device 10 determines that the maximum transmission power value (parameter value) and the NS value (if set) used in calculating the cell reselection criteria will also be used for the maximum transmission power of UL-WUS for the NES cell 20B-1. The terminal device 10 may apply the determined maximum transmission power value and the NS value (if set) to all uplink transmissions in the NES cell 20B-1, in addition to the UL-WUS signal.

[0088] The base station device 20A (normal cell 20A-1) may include transmission power control information in the MIB instead of UL-WUS setting information. The terminal device 10 measures the reception quality of the base station device 20B and simultaneously acquires MIB information from the SSB. The terminal device 10 then determines whether the cell is accessible based on the transmission power control information notified in the MIB. In other words, the terminal device 10 uses MIB information to determine whether the base station device 20B is a suitable cell for cell reselection. For example, the terminal device 10 interprets the SSB subcarrier offset value (Kssb) included in the MIB of the NES cell as information indicating transmission power control information, thereby determining whether the base station device 20B is accessible.

[0089] More specifically, the SSB subcarrier offset value (Kssb) ranges from 1 to 24 when the operating frequency is in the frequency range up to 7125 MHz (FR1), and from 1 to 12 when the operating frequency is in the frequency range from 24.25 GHz to 71 GHz (FR2). However, the base station device 20B can notify the terminal device 10 of transmission power control information by setting a value outside the above range as the Kssb value. For example, if a value of "25" is specified in FR1, this may be interpreted as indicating an NS value of "02." The Kssb value and the NS value can be any other combination. These combinations are assumed to be predetermined and shared between the base station device 20 and the terminal device 10.

[0090] Returning to Figure 4, if the terminal device 10 determines (judges, decides) that access to the cell is permitted as a result of the access judgment in step S102, it transmits UL-WUS to the base station device 20B based on the UL-WUS setting information (step S103).

[0091] The base station device 20B (NES cell 20B-1) that has received the UL-WUS transmitted from the terminal device 10 determines whether to transmit an On-demand SIB1. If it determines that transmission of the On-demand SIB1 is necessary, the base station device 20B transmits a Random Access Response (RAR) using downlink resources corresponding to the UL-WUS (step S104). The terminal device 10 that transmitted the UL-WUS starts monitoring the corresponding PDCCH (RA-RNTI) in a predetermined interval (reception window length) and attempts to detect a random access response from the base station device 20B. If the terminal device 10 successfully receives the random access response and the response contains preamble ID information (RAPID: Random Access Preamble ID) of the UL-WUS (or PRACH) transmitted by the terminal device 10, the terminal device 10 considers the On-demand SIB1 request to be successful.

[0092] Next, the base station device 20B (NES cell 20B-1) schedules the On-demand SIB1 and starts transmission within the cell (step S105). The terminal device 10 starts monitoring the PDCCH related to the scheduling of the On-demand SIB1 set in the MIB or the random access response, and attempts to acquire the On-demand SIB1. The terminal device 10 receives the On-demand SIB1, applies the acquired cell common information, camps on the cell (cell reselection), and ends the On-demand SIB1 procedure.

[0093] Note that the terminal device 10 may check (monitor) whether the cell is transmitting On-demand SIB1 before transmitting UL-WUS, and may add a decision to transmit UL-WUS only if the cell has not transmitted On-demand SIB1.

[0094] When the terminal device 10 does not detect a random access response from the base station device 20B within a predetermined interval (reception window length), it increments the counter for the number of preamble transmissions and, at the same time, increases the value of the transmission power from the current value by a predetermined step (e.g., 1 dB) as the transmission power to be applied at the time of the next UL-WUS transmission. At this time, the terminal device 10 ensures that the increased transmission power value does not exceed the maximum transmission power value determined by the method of Fig. 5 (i.e., determined by the first to fourth transmission power controls). When the increased transmission power value exceeds the maximum transmission power value determined by the method of Fig. 5, the terminal device 10 performs power control so as to transmit UL-WUS at the maximum transmission power.

[0095] As described above, according to the first embodiment, the base station device 20 can notify the terminal device 10 of transmission power control information via another base station device 20. The terminal device 10 can control transmission power before transmitting a request signal for system information to a cell that appropriately transmits system information (SIB1) for power saving, and therefore can suppress uplink interference with the base station device 20. As a result, it is possible to appropriately perform transmission power control related to wireless communication between the terminal device 10 and the base station device 20.

[0096] Second Embodiment A second embodiment will be described. Note that a description of configurations, functions, or procedures common to the first and second embodiments will be omitted. In other words, the following mainly describes the differences from the first embodiment.

[0097] As described above, the base station device 20B (NES cell 20B-1) does not transmit SIB1 until the terminal device 10 performs UL-WUS transmission, and therefore, it cannot be determined whether the NES cell 20B-1 is an accessible cell until it actually receives SIB1. This is a problem that can occur, for example, when a cell with the same cell information (PCI, downlink frequency) as the NES cell 20B-1 exists in a different PLMN.

[0098] Similarly, since the maximum transmission power is determined before receiving SIB1, there is a possibility that the maximum transmission power that is originally regulated will be exceeded due to a difference in the NS value (network signal value) that is actually notified. Therefore, the second embodiment provides a method of applying the NS value with the highest priority until receiving On-demand SIB1, and then applying the acquired NS value to determine the maximum transmission power after receiving On-demand SIB1.

[0099] When the terminal device 10 attempts to transmit UL-WUS to the base station device 20B (NES cell 20B-1), it ignores all NS values ​​obtained from the base station device 20A (normal cell 20A-1) regardless of the frequency band, and selects the NS value with the highest priority (i.e., the NS value listed first) among the NS values ​​specified corresponding to the frequency band of the NES cell 20B-1, and applies that NS value to determine the maximum transmission power.

[0100] Then, the cell reselection criteria for the NES cell 20B-1 are evaluated using the determined maximum transmission power, and if the cell reselection criteria are met, UL-WUS transmission is started for the NES cell 20B-1. At this time, the maximum transmission power of the UL-WUS to be applied is the value determined according to the NS value with the highest priority described above.

[0101] The terminal device 10 that transmitted the UL-WUS starts monitoring the corresponding PDCCH (RA-RNTI) in a predetermined interval (reception window length) and attempts to detect a random access response from the base station device 20 B. If the terminal device 10 successfully receives the random access response and the response contains preamble ID information (RAPID: Random Access Preamble ID) of the UL-WUS (or PRACH) transmitted by the terminal device 10 itself, the terminal device 10 considers the On-demand SIB1 request to be successful.

[0102] Next, the base station device 20B (NES cell 20B-1) schedules the On-demand SIB1 and starts transmission within the cell (step S105). The terminal device 10 starts monitoring the PDCCH related to the scheduling of the On-demand SIB1 set in the MIB or the random access response, and attempts to acquire the On-demand SIB1. The terminal device 10 receives the On-demand SIB1, applies the acquired cell common information, camps on the cell (cell reselection), and ends the On-demand SIB1 procedure.

[0103] At this time, the terminal device 10 discards the NS value and maximum transmission power value that have been used up until then, and applies the NS value acquired from the On-demand SIB1 to determine the maximum transmission power in the base station device 20B (NES cell 20B-1).

[0104] As described above, according to the second embodiment, the terminal device 10 can autonomously control transmission power before transmitting a request signal for system information to a cell that appropriately transmits system information (SIB1) for power saving, thereby making it possible to suppress uplink interference with the base station device 20. As a result, it becomes possible to appropriately perform transmission power control related to wireless communication between the terminal device 10 and the base station device 20.

[0105] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention also includes equivalents. Furthermore, the aspects / embodiments described in this specification may be used alone, in combination, or switched depending on the implementation.

[0106] <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 with reference to FIGS. 6 and 7. FIG.

[0107] 6 is a diagram illustrating an example of the hardware configuration of the terminal device 10. As illustrated in FIG. 6, the terminal device 10 includes, as hardware components, a radio frequency (RF) circuit 32 including an antenna 31, a central processing unit (CPU) 33, and a memory 34. The terminal device 10 may further include a display device such as a liquid crystal display (LCD) connected to the CPU 33. The memory 34 includes at least one of a random access memory (RAM) such as a synchronous dynamic random access memory (SDRAM), a read only memory (ROM), and a flash memory, and stores programs, control information, and data signals.

[0108] The correspondence between the functional configuration of the terminal device 10 shown in Fig. 2 and the hardware configuration of the terminal device 10 shown in Fig. 6 will be described. The transmitting / receiving antenna unit 19, the transmitter unit 17, and the receiver unit 15 are realized by, for example, an RF circuit 32, or an antenna 31 and an RF circuit 32. The control unit 13 and the processing unit 11 are realized by, for example, a CPU 33, a memory 34, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and a large scale integration (LSI).

[0109] 7 is a diagram illustrating an example of the hardware configuration of the base station device 20. As shown in FIG. 7, the base station device 20 includes, as hardware components, an RF circuit 42 equipped with an antenna 41, a CPU 43, a DSP 44, a memory 45, and a network IF (Interface) 46. The CPU 43 is connected via a bus to enable input and output of various signals and data signals. The memory 45 includes at least one of a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data signals.

[0110] The correspondence between the functional configuration of the base station device 20 shown in Fig. 3 and the hardware configuration of the base station device 20 shown in Fig. 7 will be described. The transmitting / receiving antenna unit 29, the transmitter 27, and the receiver 25 are realized by, for example, an RF circuit 42, or an antenna 41 and an RF circuit 42. The control unit 23 and the processing unit 21 are realized by, for example, a CPU 43, a DSP 44, a memory 45, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an ASIC, an FPGA, and an LSI.

[0111] 1 Wireless communication system 10 Terminal device 20, 20A, 20B Base station device 20A-1 Normal cell 20B-1 NES cell 30 Core network 11, 21 Processing unit 13, 23 Control unit 15, 25 Receiving unit 17, 27 Transmitting unit 19, 29 Transmitting and receiving antenna unit 31, 41 Antenna 32, 42 RF circuit 33, 43 CPU 34, 45 Memory 44 DSP 46 Network IF 111, 211 Radio resource processing unit 113 Control processing unit 213 SIB1 control processing unit

Claims

1. A terminal device capable of communicating with a first base station device and a second base station device, comprising: a transmitter that transmits a request signal to the second base station device based on setting information of the request signal, which is acquired from the first base station device, requesting essential system information from the second base station device; a receiver that receives from the second base station device the essential system information transmitted in response to the request signal; and a controller that controls transmission power when transmitting the request signal to the second base station device by applying a maximum transmission power value determined based on transmission power control information acquired from the first base station device, wherein the transmission power control information is divided into first transmission power control information that is not associated with the setting information of the second base station device and second transmission power control information that is associated with the second base station device, and the terminal device determines the maximum transmission power value using the first transmission power control information for the first base station device and the second transmission power control information for the second base station device.

2. The terminal device according to claim 1, wherein the essential system information requested in the request signal is System Information Block Type 1 (SIB1).

3. A terminal device as described in claim 2, which, when the second transmission power control information associated with the second base station device is not set, determines a maximum transmission power value for the first base station device and the second base station device using the first transmission power control information corresponding to each frequency band.

4. The terminal device according to claim 2, wherein the maximum transmission power value determined based on the first transmission power control information and the second transmission power control information is applied to evaluate cell reselection criteria.

5. A terminal device capable of communicating with a first base station device and a second base station device, comprising: a transmitter that transmits a request signal requesting essential system information, acquired from the first base station device, to the second base station device based on configuration information of the request signal; a receiver that receives the essential system information transmitted in response to the request signal; and a control unit that controls transmission power by applying a maximum transmission power value determined based on the configuration information when transmitting the request signal to the second base station device, wherein the terminal device determines the maximum transmission power value by applying, as the maximum transmission power value, a value that is supportable by the terminal device and has the highest priority among network signal values ​​specified corresponding to the uplink frequency band indicated in the configuration information.

6. A base station device in a communication system including a first cell that periodically transmits essential system information and a second cell that transmits the essential system information in response to a request from a terminal device, comprising: a receiving unit that receives configuration information of a request signal for the essential system information of the second cell used by the terminal device; a transmitting unit that transmits the configuration information of the request signal, first transmission power control information that is not associated with the configuration information for the second cell, and second transmission power control information associated with the second cell to the terminal device using the first cell; and a control unit that sets the first transmission power control information to the terminal device to determine a maximum transmission power for the first cell, and sets the second transmission power control information to determine a maximum transmission power for the second cell.

7. The base station apparatus according to claim 6, wherein the essential system information requested in the request signal is System Information Block Type 1 (SIB1).

8. A base station device as described in claim 7, which, by notifying the terminal device of the first transmission power control information and the second transmission power control information, causes the terminal device to evaluate cell reselection criteria applying a maximum transmission power value determined based on the first transmission power control information and the second transmission power control information.

9. A control method for a terminal device capable of communicating with a first base station device and a second base station device, comprising: a transmitting means for transmitting a request signal to the second base station device based on setting information of the request signal, which is acquired from the first base station device, requesting essential system information from the second base station device; a receiving means for receiving the essential system information transmitted in response to the request signal; and a control means for controlling transmission power by applying a maximum transmission power value determined based on transmission power control information acquired from the first base station device when transmitting the request signal to the second base station device, wherein the transmission power control information is divided into first transmission power control information that is not associated with the setting information of the second base station device and second transmission power control information that is associated with the second base station device, and the terminal device determines the maximum transmission power value using the first transmission power control information for the first base station device and the second transmission power control information for the second base station device.

10. A control method for a terminal device capable of communicating with a first base station device and a second base station device, comprising: a transmitting means for transmitting a request signal to the second base station device based on configuration information of the request signal, which is acquired from the first base station device and requests essential system information from the second base station device; a receiving means for receiving the essential system information transmitted in response to the request signal; and a control means for controlling transmission power by applying a maximum transmission power value determined based on the configuration information when transmitting the request signal to the second base station device, wherein the control method determines the maximum transmission power value by applying, as the maximum transmission power value, a value that is supportable by the terminal device and has the highest priority among network signal values ​​defined for the uplink frequency band indicated in the configuration information.

11. A method for controlling a base station device in a communication system including a first cell that periodically transmits essential system information and a second cell that transmits the essential system information in response to a request from a terminal device, the method comprising: a receiving means for receiving configuration information of a request signal for the essential system information of the second cell used by the terminal device; a transmitting means for transmitting the configuration information of the request signal, first transmission power control information that is not associated with the configuration information for the second cell, and second transmission power control information associated with the second cell to the terminal device using the first cell; and a control means for setting the first transmission power control information to the terminal device to determine a maximum transmission power for the first cell, and setting the second transmission power control information to determine a maximum transmission power for the second cell.

Images