Communication device, base station, and communication method

Abstract

A communication device (100) according to an embodiment of the present invention communicates with a first network (200A) and a second network (200B) by using a plurality of subscriber identification modules. The communication device is provided with: a reception unit (120R) that receives a radio resource control (RRC) reconfiguration message from the second network; and a control unit (130) that, on the basis of the RRC reconfiguration message, determines whether or not to transmit capability restriction information pertaining to the temporarily restricted capability of the communication device.

Description

Communication device, base station, and communication method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Patent Application No. 2023-168514, filed September 28, 2023, the entire contents of which are incorporated herein by reference.

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

[0003] In Release 18 of 3GPP (registered trademark; the same applies hereinafter) (3rd Generation Partnership Project), a standardization project for mobile communication systems, a work item has been launched regarding a communication device that uses multiple subscriber identity modules to communicate with multiple networks.

[0004] For example, consider a case in which a communication device starts communication with another network (hereinafter, "second network") while communicating with a certain network (hereinafter, "first network"). Because the communication with the first network partially uses the communication device's capacity, the communication device's capacity available for communication with the second network is temporarily reduced (i.e., limited). Meanwhile, the second network is unaware that the communication device's capacity is temporarily limited, and therefore determines settings for the communication device based on the communication device's normal capacity. In this case, the communication device, whose capacity is temporarily limited, may be unable to communicate with the second network according to the settings determined by the second network.

[0005] Therefore, a method is being considered in which a communication device transmits an early indication to a second network to notify the second network that the communication device's capabilities are temporarily restricted, and then transmits information regarding the communication device's restricted capabilities (hereinafter referred to as capability restriction information) (see, for example, non-patent document 1).

[0006] 3GPP contribution “R2-2304202” (Report on LTE legacy, XR, QoE and MUSIM)

[0007] A communication device according to a first aspect is a communication device that communicates with a first network and a second network using a plurality of subscriber identity modules, the communication device comprising: a receiver that receives a radio resource control (RRC) reconfiguration message from the second network; and a controller that determines, based on the RRC reconfiguration message, whether to transmit capability restriction information related to temporarily restricted capabilities of the communication device.

[0008] A second aspect of the present invention provides a base station of a second network, the base station comprising a transmitter configured to transmit a radio resource control (RRC) reconfiguration message to a communication device communicating with a first network and the second network using a plurality of subscriber identity modules, the RRC reconfiguration message being used in the communication device to determine whether to transmit capability restriction information relating to temporarily restricted capabilities of the communication device.

[0009] A third aspect of the present invention relates to a communication method executed in a communication device that communicates with a first network and a second network using a plurality of subscriber identity modules, the communication method comprising the steps of receiving a Radio Resource Control (RRC) reconfiguration message from the second network, and determining, based on the RRC reconfiguration message, whether to transmit capability restriction information related to temporarily restricted capabilities of the communication device.

[0010] Objects, features, advantages, etc. of the present disclosure will become clearer from the following detailed description with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an example configuration of a mobile communication system according to an embodiment. FIG. 2 is a diagram illustrating an example configuration of a protocol stack of the mobile communication system according to the embodiment. FIG. 3 is a diagram illustrating an example configuration of a protocol stack of the mobile communication system according to the embodiment. FIG. 4 is a diagram for explaining an assumed scenario. FIG. 5 is a diagram illustrating an example configuration of a UE (user equipment) according to the embodiment. FIG. 6 is a diagram illustrating an example configuration of a base station according to the embodiment. FIG. 7 is a sequence diagram illustrating a first operation example according to the embodiment. FIG. 8 is a sequence diagram illustrating a second operation example according to the embodiment. FIG. 9 is a sequence diagram illustrating a third operation example according to the embodiment. FIG. 10 is a flowchart illustrating a fourth operation example according to the embodiment. FIG. 11 is a flowchart illustrating a fifth operation example according to the embodiment. FIG. 12 is a flowchart (part 1) illustrating a sixth operation example according to the embodiment. FIG. 13 is a flowchart (part 2) illustrating the sixth operation example according to the embodiment.

[0011] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0012] However, existing 3GPP technical specifications do not specify the operation of a communication device with respect to the transmission of capability restriction information, which raises concerns that the communication device may not be able to properly transmit the capability restriction information. For example, even if the second network (e.g., a base station) does not support or permit the communication device to transmit the capability restriction information, a malfunction may occur if the communication device transmits the capability restriction information.

[0013] Therefore, an object of the present disclosure is to provide a communication device, a base station, and a communication method that enable a communication device that communicates with multiple networks to appropriately transmit capacity restriction information.

[0014] [Embodiment] (System Configuration) The configuration of a mobile communication system 1 according to an embodiment will be described with reference to Fig. 1. In the following, an example in which the mobile communication system 1 is a fifth-generation system (5G / NR (New Radio / NR Radio Access)) conforming to the 3GPP standard will be mainly described, but a fourth-generation system (4G / LTE: Long Term Evolution) system and / or a sixth-generation system may also be applied at least in part to the mobile communication system 1.

[0015] As shown in FIG. 1, a mobile communication system 1 according to the embodiment includes a user equipment (UE) 100, a first network 200A, and a second network 200B.

[0016] The UE 100 is an example of a communication device. The UE 100 may be a mobile wireless communication device. The UE 100 may be a device used by a user. The UE 100 may be a user equipment defined by 3GPP technical specifications. For example, the UE 100 may be a mobile phone terminal (including a smartphone), a tablet terminal, a laptop PC, a communication module (including a communication card or chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (e.g., a Vehicle UE), or an aircraft or a device provided in an aircraft (e.g., an Aerial UE). The UE 100 may be referred to by other names such as a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, or a remote unit.

[0017] The UE 100 can communicate with multiple networks using multiple subscriber identity modules (SIMs). The UE 100 may be a multi-SIM device that supports multiple SIMs. While an example in which the UE 100 supports two SIMs will be mainly described below, the UE 100 may also support three or more SIMs. "Supporting multiple SIMs" means that the UE 100 has the ability to handle multiple SIMs, and does not necessarily require that the UE 100 be equipped with multiple SIMs. Such a UE 100 may be referred to as a "UE that supports multiple SIMs." The SIM is not limited to a card-type SIM (a so-called SIM card), but may also be an embedded SIM (a so-called eSIM) that is previously embedded in the UE 100. The SIM may be referred to as a Universal Subscriber Identity Module (USIM). Therefore, the UE 100 that can communicate with a plurality of networks using a plurality of SIMs may be referred to as a Multi-USIM (MUSIM) UE.

[0018] The first network 200A is a network associated with one SIM of the UE 100. The second network 200B is a network associated with the other SIM of the UE 100. The UE 100 performs location registration with the first network 200A using one SIM, and performs location registration with the second network 200B using the other SIM. That is, the UE 100 is present in each of the first network 200A and the second network 200B. The first network 200A and the second network 200B may be networks of different telecommunications carriers. However, the first network 200A and the second network 200B may be networks of the same telecommunications carrier. Different PLMN (Public Land Mobile Network) IDs may be assigned to the first network 200A and the second network 200B.

[0019] The first network 200A includes a base station 210A constituting a radio access network and a core network 220A. The core network 220A includes, as core network devices, a mobility management device 221A and a gateway device 222A. Similarly, the second network 200B includes a base station 210B constituting a radio access network and a core network 220B. The core network 220B includes, as core network devices, a mobility management device 221B and a gateway device 222B. Hereinafter, when there is no need to distinguish between the base stations 210A and 200B, they will be simply referred to as base station 210; when there is no need to distinguish between the mobility management devices 221A and 221B, they will be simply referred to as mobility management device 221; and when there is no need to distinguish between the gateway devices 222A and 222B, they will be simply referred to as gateway device 222.

[0020] The base station 210 is a wireless communication device that performs wireless communication with the UE 100. The base station 210 manages one or more cells. One or more base stations 210 may correspond to one or more cells. In this embodiment, the base station 210 may be replaced with a cell. The base station 210 performs wireless communication with the UE 100 that has established a connection with its own cell in the radio resource control (RRC) layer. The base station 210 has a radio resource management (RRM) function, a user data (hereinafter simply referred to as "data") routing function, a measurement control function for mobility control and scheduling, and the like. The term "cell" is used to refer to the smallest unit of a wireless communication area. The term "cell" is also used to refer to functions or resources for performing wireless communication with the UE 100. One cell belongs to one carrier frequency. FIG. 1 illustrates an example in which the base station 210A manages cell C1 and the base station 210B manages cell C2. The UE 100 is located in the overlapping area of ​​the cells C1 and C2.

[0021] The base station 210 may be a gNB, which is a 5G / NR base station, or an eNB, which is a 4G / LTE base station. The following mainly describes an example in which the base station 210 is a gNB. The base station 210 may be functionally divided into a CU (Central Unit) and a DU (Distributed Unit). The base station 210 may be a relay node such as an IAB (Integrated Access and Backhaul) node.

[0022] The mobility management device 221 is a device corresponding to the control plane and performs various mobility management for the UE 100. The mobility management device 221 communicates with the UE 100 using NAS (Non-Access Stratum) signaling and manages information on the tracking area in which the UE 100 is located. The mobility management device 221 performs paging through the base station 210 to notify the UE 100 of an incoming call. The mobility management device 221 may be a 5G / NR AMF (Access and Mobility Management Function) or a 4G / LTE MME (Mobility Management Entity).

[0023] The gateway device 222 is a device corresponding to the user plane and controls the transfer of data of the UE 100. The gateway device 222 may be a 5G / NR UPF (User Plane Function) or a 4G / LTE S-GW (Serving Gateway).

[0024] (Configuration Example of Protocol Stack) An example of the configuration of a protocol stack of the mobile communication system 1 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 shows an example of the configuration of a protocol stack related to the control plane. As shown in Fig. 2, the protocol of the wireless section between the UE 100 and the base station 210 has a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer.

[0025] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 210 via a physical channel.

[0026] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of base station 210 via a transport channel. The MAC layer of base station 210 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resources to be allocated to UE 100.

[0027] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 210 via logical channels.

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

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

[0030] The RRC layer controls logical channels, transport channels, and physical channels according to the establishment, re-establishment, and release of radio bearers. RRC signaling for various settings is transmitted between the RRC layer of the UE 100 and the RRC layer of the base station 210. When an RRC connection exists between the RRC of the UE 100 and the RRC of the base station 210, the UE 100 is in an RRC connected state. When there is no RRC connection between the RRC of the UE 100 and the RRC of the base station 210, the UE 100 is in an RRC idle state. When the RRC connection between the RRC of the UE 100 and the RRC of the base station 210 is suspended, the UE 100 is in an RRC inactive state.

[0031] The NAS layer, which is positioned above the RRC layer, performs session management and mobility management for the UE 100. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the mobility management device 221.

[0032] The modes (NAS states) in the NAS layer of UE 100 include idle mode and connected mode. In connected mode, context information of UE 100 is held in the network, and in idle mode, context information of UE 100 is not held in the network. When UE 100 is in connected mode, UE 100 is in an RRC connected state or an RRC inactive state. When UE 100 is in idle mode, UE 100 is in an RRC idle state.

[0033] The mode at the NAS layer may be a 5G Mobility Management (5GMM) mode, in which the connected mode may be a 5GMM-connected mode and the idle mode may be a 5GMM-idle mode.

[0034] As shown in FIG. 3, the UE 100 and the base station 210 include a PHY layer, a MAC layer, an RLC layer, a PDCP layer, and an SDAP (Service Data Protocol) layer as protocols related to the user plane.

[0035] The SDAP layer maps Quality of Service (QoS) flows to data radio bearers and assigns QoS flow identification (ID) to both the uplink (UL) and downlink (DL). Note that the SDAP layer may not be present in an LTE system.

[0036] The UE 100 has an application layer and the like in addition to the radio interface protocol.

[0037] (Assumed Scenario) An assumed scenario in the mobile communication system 1 according to the embodiment will be described with reference to Fig. 4. In Release 18 of 3GPP, which is the standardization project for the mobile communication system 1, a work item has been launched regarding a communication device that uses multiple subscriber identity modules to communicate with multiple networks.

[0038] For example, as shown in FIG. 4A , when UE 100 communicates with first network 200A using SIM 111, UE 100 can use first transceiver 121 and second transceiver 122 for communication with first network 200A. Assume a case in which UE 100 subsequently starts communication with second network 200B while communicating with first network 200A. In this case, as shown in FIG. 4B , when UE 100 communicates with second network 200B using SIM 112, it is assumed that UE 100 switches second transceiver 122 for communication with second network 200B. This allows UE 100 to communicate with second network 200B using second transceiver 122 while maintaining communication with first network 200A using first transceiver 121.

[0039] Here, the UE 100 uses part of its communication device capacity for communication with the first network 200A (for example, as shown in FIG. 4B , the UE 100 uses the first transceiver unit 121 for communication with the first network 200A), and therefore the capacity of the UE 100 available for communication with the second network 200B is temporarily reduced (i.e., limited). On the other hand, the second network 200B is unaware that the capacity of the UE 100 is temporarily limited, and therefore it is assumed that the second network 200B determines the settings for the UE 100 based on the normal capacity of the UE 100. In this case, the UE 100, whose capacity is temporarily limited, may not be able to communicate with the second network 200B in accordance with the settings determined by the second network 200B.

[0040] Therefore, a method is being considered in which UE100 sends an early indication to the second network 200B to notify that the capabilities of UE100 are temporarily restricted, and then sends information regarding the restricted capabilities of UE100 (hereinafter referred to as capability restriction information).

[0041] However, since the existing 3GPP technical specifications do not specify the operation of the UE 100 regarding the transmission of the capability restriction information, there is a concern that the UE 100 may not be able to properly transmit the capability restriction information. For example, even if the second network (e.g., the base station 210) does not support or permit the UE 100 to transmit the capability restriction information, a malfunction may occur if the UE 100 transmits the capability restriction information. Below, an operation for enabling the UE 100 that communicates with multiple networks to properly transmit the capability restriction information will be described.

[0042] For example, the second network 200B can know that the capability of the UE 100 is temporarily restricted by receiving an early indication from the UE 100. However, the second network 200B cannot know how long the capability of the UE 100 is temporarily restricted until it receives the capability restriction information. Therefore, a case is assumed in which the second network 200B suspends configuration for the UE 100 until it receives the capability restriction information from the UE 100. Here, when the UE 100 transmits the capability restriction information using a UE assistance information message, configuration information for permitting transmission of the UE assistance information message is included in the RRC reconfiguration message. Therefore, when the second network 200B suspends configuration for the UE 100, i.e., suspends transmission of the RRC reconfiguration message, there is a problem in that the UE 100 cannot transmit the capability restriction information indefinitely. An operation for enabling the UE 100 communicating with multiple networks to appropriately transmit capability restriction information will be described below.

[0043] Furthermore, since the transmission of the UE assistance information message depends on the implementation of the UE 100, there is a concern that the UE 100 may not transmit the capability restriction information. An operation for enabling the UE 100 that communicates with a plurality of networks to appropriately transmit the capability restriction information will be described below.

[0044] (Example of UE configuration) An example of the configuration of UE 100 will be described with reference to Fig. 5. As shown in Fig. 6, UE 100 has antenna 101, antenna 102, SIM 111, SIM 112, communication unit 120, and control unit 130. Antenna 101 and antenna 102 may be provided outside UE 100. SIM 111 and SIM 112 may be SIM cards or eSIMs.

[0045] The SIM 111 stores subscriber information and setting information necessary for the UE 100 to communicate with the first network 200A. The SIM 111 stores identification information of the UE 100 in the first network 200A, such as a telephone number and an IMSI (International Mobile Subscriber Identity). The SIM 111 corresponds to a first subscriber information module. The UE 100 communicates with the first network 200A using the SIM 111.

[0046] The SIM 112 stores subscriber information and setting information necessary for the UE 100 to communicate with the second network 200B. The SIM 112 stores identification information of the UE 100 in the second network 200B, such as a telephone number and an IMSI. The SIM 112 corresponds to a second subscriber information module. The UE 100 communicates with the second network 200B using the SIM 112.

[0047] The communication unit 120, under the control of the control unit 130, performs wireless communication with the first network 200A and the second network 200B via the antenna 101 and the antenna 102. The communication unit 120 has a plurality of transceivers. The transceivers may be referred to as transceivers or as radio frequency (RF) chains. In this embodiment, the communication unit 120 has a first transceiver 121 and a second transceiver 122. The first transceiver 121 and the second transceiver 122 each have a receiving unit 120R and a transmitting unit 120T. The receiving unit 120R converts radio signals received by each antenna into received signals, which are baseband signals, performs signal processing on the received signals, and outputs the received signals to the control unit 130. The transmitting unit 120T performs signal processing on transmission signals, which are baseband signals, output by the control unit 130, converts the transmitted signals into radio signals, and transmits the radio signals from each antenna. The receiving unit 120R may be referred to as a receiver, an Rx chain, or an Rx branch. The transmitting unit 120T may be referred to as a transmitter, a Tx chain, or a Tx branch. In this embodiment, the first transceiver unit 121 has a first receiving unit 121R as the receiving unit 120R and a first transmitting unit 121T as the transmitting unit 120T. The second transceiver unit 122 has a second receiving unit 122R as the receiving unit 120R and a second transmitting unit 122T as the transmitting unit 120T.

[0048] The control unit 130 controls the communication unit 120 and performs various controls in the UE 100. The control unit 130 controls communication with the first network 200A using the SIM 111 and controls communication with the second network 200B using the SIM 112. The control unit 130 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in processing by the processor. The memory may include at least one of ROM (Read Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), RAM (Random Access Memory), and flash memory. The processor may include a digital signal processor (DSP) that performs digital processing of digital signals, and a central processing unit (CPU) that executes programs. Note that a portion of the memory may be provided in the communication unit 120. The DSP may also be provided in the communication unit 120.

[0049] In the UE 100 configured in this manner, the receiver 120R receives a message from the second network 200B when the capability of the UE 100 in the second network 200B is temporarily restricted due to communication with the first network 200A. The controller 130 determines, based on the message, whether or not transmission of capability restriction information related to the temporarily restricted capability of the UE 100 is permitted. The transmitter 120T transmits the capability restriction information to the second network 200B when transmission of the capability restriction information is permitted. As a result, the UE 100 transmits the capability restriction information after determining, based on the message from the second network 200B, whether or not transmission of the capability restriction information is permitted, and therefore does not freely transmit the capability restriction information without being restricted by the second network 200B. As a result, the UE 100 is able to appropriately transmit the capability restriction information.

[0050] In addition, the operation of the functional units (e.g., at least one of antenna 101, antenna 102, SIM 111, SIM 112, communication unit 120, and control unit 130) of UE 100 may be described as the operation of UE 100.

[0051] (Configuration Example of Base Station) An example configuration of the base station 210A of the first network 200A will be described with reference to Fig. 6. Note that the base station 210B of the second network 200B has the same configuration as the base station 210A, and therefore its description will be omitted. As shown in Fig. 5, the base station 210A has an antenna 211, a wireless communication unit 212, a network communication unit 213, and a control unit 214.

[0052] The wireless communication unit 212 communicates with the UE 100 via the antenna 211 under the control of the control unit 214. The wireless communication unit 212 has a receiving unit 212R and a transmitting unit 212T. The receiving unit 212R converts the wireless signal received by the antenna 211 into a received signal, which is a baseband signal, performs signal processing on the received signal, and outputs the received signal to the control unit 214. The transmitting unit 212T performs signal processing on the transmission signal, which is a baseband signal, output by the control unit 214, converts the transmission signal into a wireless signal, and transmits the wireless signal from the antenna 211.

[0053] The network communication unit 213 is connected to the core network 220A. Under the control of the control unit 214, the network communication unit 213 performs network communication with the mobility management device 221A and the gateway device 222A.

[0054] The control unit 214 controls the wireless communication unit 212 and performs various controls in the base station 210A. The control unit 214 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in processing by the processor. The memory may include at least one of ROM, EPROM, EEPROM, RAM, and flash memory. The processor may include a digital signal processor (DSP) that performs digital processing of digital signals and a central processing unit (CPU) that executes programs. Note that a portion of the memory may be provided in the wireless communication unit 212. The DSP may also be provided in the wireless communication unit 212.

[0055] In the base station 210 configured in this manner, the transmitter 212T transmits to the UE 100 a message for the UE 100 to determine whether or not transmission of capability restriction information is permitted when the capability of the UE 100 in the second network 200B is temporarily restricted due to communication with another network (e.g., the first network 200A). As a result, the UE 100 transmits the capability restriction information after determining whether or not transmission of the capability restriction information is permitted based on the message from the second network 200B. Therefore, the UE 100 does not freely transmit capability restriction information without being restricted by the second network 200B. As a result, the UE 100 can appropriately transmit the capability restriction information.

[0056] The operation of the functional units (e.g., at least one of the antenna 211, the wireless communication unit 212, the network communication unit 213, and the control unit 214) included in the base station 210A may be described as the operation of the base station 210A.

[0057] (Operation of Mobile Communication System) An example of the operation of the mobile communication system will be described with reference to FIGS.

[0058] (1) First Operation Example A first operation example of the mobile communication system 1 will be described with reference to FIG. 7 . The UE 100 is communicating with the first network 200A using, for example, the SIM 111. The UE 100 is communicating in the first network 200A. For example, the UE 100 may be provided with a service such as a voice call from the first network 200A. When the UE 100 is communicating with the first network 200A, the UE 100 may be continuously exchanging data with the network, either continuously or discontinuously. Note that when the UE 100 is communicating with the second network 200B, the capabilities of the UE 100 in the first network 200A are temporarily restricted.

[0059] In addition, when UE100 is communicating with a certain network, it may refer to being in an RRC connected state in the certain network, or being in a state in which paging (messages) can be received in the certain network (for example, being in any of an RRC connected state, an RRC idle state, or an RRC inactive state), or it may refer to being registered in the certain network.

[0060] In this operation example, as shown in Fig. 7, the UE 100 is in an RRC connected state in the first network 200A. In the RRC connected state, an RRC connection is established between the UE 100 and the first network 200A (the base station 210A).

[0061] The UE 100 may communicate with a primary cell (P cell) and a secondary cell (S cell) of a base station 210A of the first network 200A. One base station 210A of the first network 200A may manage the P cell and the S cell. Alternatively, one base station 210A of the first network 200A may manage the P cell, and another base station of the first network 200A may manage the S cell.

[0062] The P cell may be a P cell in carrier aggregation operation. The S cell may be an S cell in carrier aggregation operation. The P cell may be a P cell belonging to a master cell group (MCG) in dual connectivity operation. The S cell may be a primary secondary cell (PS cell) belonging to a secondary cell group (SCG) in dual connectivity operation. The S cell may be a secondary cell (S cell) belonging to the master cell group (MCG) and / or the secondary cell group (SCG) in dual connectivity operation. Here, the P cell of the master cell group (MCG) and / or the primary secondary cell (PS cell) belonging to the secondary cell group (SCG) in dual connectivity operation are also referred to as special cells (SP cells).

[0063] As shown in Fig. 7, the UE 100 may be in an RRC idle state or an RRC inactive state in the second network 200B. The UE 100 may monitor paging from the second network 200B and receive system information blocks (SIBs) from the second network 200B while maintaining an RRC connected state in the first network 200A. For example, the UE 100 can monitor paging and receive SIBs in the second network 200B during a period when communication with the first network 200A is interrupted. Because the UE 100 is communicating with the first network 200A, the capabilities of the UE 100 in the second network 200B are temporarily limited.

[0064] Note that the communication between the UE 100 and the first network 200A may be communication between the UE 100 and any of the nodes belonging to the first network 200A (for example, the base station 210A, the mobility management device 221A, or the gateway device 222A). Also, the communication between the UE 100 and the base station 210A may be, for the UE 100, communication between the UE 100 and a cell (for example, the P cell or the S cell) of the base station 210A. The same applies to the communication between the UE 100 and the second network 200B.

[0065] For example, the UE 100 may communicate with the first network 200A via the first transceiver 121 (specifically, the first receiving unit 121R / the first transmitting unit 121T), and the UE 100 may communicate with the second network 200B via the second transceiver 122 (specifically, the second receiving unit 122R / the second transmitting unit 122T). In the following, for ease of explanation, both the first receiving unit 121R and the second receiving unit 122R will be referred to as the receiving unit 120R, and both the first transmitting unit 121T and the second transmitting unit 122T will be referred to as the transmitting unit 120T.

[0066] Step S101: The transmitter 212T of the base station 210B broadcasts a message including a system information block (SIB). The SIB (message including the SIB) is broadcast from the second network 200B.

[0067] The receiver 120R of the UE 100 receives a message including an SIB. Because the UE 100 is communicating with the first network 200A, the receiver 120R receives the message from the second network 200B when the communication capacity in the second network 200B is temporarily restricted due to the communication with the first network 200A. Note that the receiver 120R receives the message before the random access procedure with the second network 200B is completed. In this operation example, the receiver 120R receives the message before starting the random access procedure with the second network 200B. Furthermore, the receiver 120R receives the message before transmitting the early indication.

[0068] The SIB may include information for determining whether or not transmission of an early indication (i.e., an early indication) described below is permitted (hereinafter referred to as early indication determination information (or EI determination information) as appropriate). The EI determination information may be any of the following information: - Information indicating that (the base station and / or cell) permits (or instructs) transmission of an early indication - Information indicating that (the base station and / or cell) does not permit (or instructs) transmission of an early indication - Information indicating whether (the base station and / or cell) permits (or instructs) transmission of an early indication - Information indicating (the base station and / or cell) supports early indication - Information indicating (the base station and / or cell) does not support early indication - Information indicating whether (the base station and / or cell) supports early indication

[0069] For example, when the control unit 214 of the base station 210B permits (or instructs) the transmission of an early indication, the control unit 214 may include, in the SIB, information indicating that the transmission of an early indication is permitted and / or information indicating that the early indication is supported. Alternatively, when the control unit 214 permits the transmission of an early indication, the control unit 214 may not include, in the SIB, information indicating that the transmission of an early indication is not permitted and / or information indicating that the early indication is not supported.

[0070] On the other hand, for example, when the control unit 214 does not permit (or instruct) the transmission of an early indication, the control unit 214 may include, in the SIB, information indicating that the transmission of an early indication is not permitted and / or information indicating that the early indication is not supported. Alternatively, when the control unit 214 does not permit the transmission of an early indication, the control unit 214 may not include, in the SIB, information indicating that the transmission of an early indication is permitted and / or information indicating that the early indication is supported.

[0071] The SIB may be SIB1, which includes information relevant to evaluating whether the UE 100 is permitted to access the cell and specifies scheduling of other system information, or a specific SIB different from SIB1. The specific SIB may be an SIB including information for controlling MUSIM UEs. The message including SIB1 may be a BCCH-DL-SCH message, which is an RRC message that may be sent from the network to the UE 100 via a downlink shared channel (DL-SCH) on a broadcast control channel (BCCH) logical channel. The message including the specific SIB may be a system information message used to carry one or more system information blocks or a positioning system information block, or may be a BCCH-DL-SCH message.

[0072] The message in this step is a message for UE100 to determine whether or not the transmission of the capability restriction information described below is permitted when the capability of UE100 in second network 200B is temporarily restricted due to communication with another network (e.g., first network 200A).

[0073] Step S102: The control unit 130 of the UE 100 determines whether transmission of an early indication is permitted. The control unit 130 may make this determination based on the message. The control unit 130 may make this determination based on, for example, an SIB (e.g., SIB1 or a specific SIB) included in the message. The control unit 130 may also make this determination based on EI determination information.

[0074] The control unit 130 may determine that transmission of an early indication is permitted when the SIB includes information indicating that transmission of an early indication is permitted and / or information indicating that early indication is supported. Alternatively, the control unit 130 may determine that transmission of an early indication is permitted when the SIB does not include information indicating that transmission of an early indication is not permitted and / or information indicating that early indication is not supported, i.e., when the SIB does not include EI determination information.

[0075] On the other hand, the control unit 130 may determine that transmission of an early indication is not permitted when the SIB includes information indicating that transmission of an early indication is not permitted and / or information indicating that early indication is not supported. Alternatively, the control unit 130 may determine that transmission of an early indication is not permitted when the SIB does not include information indicating that transmission of an early indication is permitted and / or information indicating that early indication is supported, i.e., when the SIB does not include EI determination information.

[0076] Furthermore, the control unit 130 of the UE 100 may determine whether or not transmission of capability restriction information is permitted. For example, when the control unit 130 determines that transmission of early indication is permitted (or early indication is supported) based on a message (e.g., EI determination information), the control unit 130 may determine that transmission of capability restriction information is permitted. Therefore, for example, when transmission of early indication is permitted, the control unit 130 may determine that transmission of capability restriction information is permitted. On the other hand, for example, when the control unit 130 determines that transmission of early indication is not permitted based on a message (e.g., EI determination information), the control unit 130 may determine that transmission of capability restriction information is not permitted. Therefore, for example, when transmission of early indication is not permitted, the control unit 130 may determine that transmission of capability restriction information is not permitted.

[0077] Thereafter, the UE 100 performs control to start communication with the second network 200B. For example, the UE 100 may perform the following process based on receiving paging from the second network 200B. Furthermore, the UE 100 (and the base station 210B) may start a random access (RA) procedure. The UE 100 may perform the following process during the RA procedure.

[0078] Note that, for example, when the UE 100 is communicating with the P cell and the S cell in the first network 200A, the UE 100 may perform a process to release the connection (communication) with the S cell before performing the following process. For example, the UE 100 may transmit, to the base station 210A that manages the P cell, a message (for example, a UE assistance information message) including capability restriction information indicating that the capability of the UE 100 is temporarily restricted in the first network 200A. If the S cell is managed by another base station, the base station 210A may transmit a message to release the S cell to the other base station. Thereafter, the base station 210A may transmit, to the UE 100, an RRC reconfiguration message to release the S cell. The UE 100 may perform the following process after releasing the S cell. Note that the UE 100 may perform the following process, for example, using a communication unit (for example, the second transceiver unit 122) that was used for communication with the S cell, rather than a transceiver unit (for example, the first transceiver unit 121) that is used for communication with the P cell. For example, UE 100 may continue to use the transceiver unit (e.g., first transceiver unit 121) used for communication with the P cell of the first network 200A for communication with the P cell, while using the communication unit (e.g., second transceiver unit 122) used for communication with the S cell of the first network 200A as the following transmitter unit 120T and / or receiver unit 120R for communication with the second network 200B.

[0079] Step S103: The transmitter 120T of the UE 100 (for example, the second transmitter 122T used for communication with the S cell of the first network 200A) transmits a message for transitioning to an RRC connected state to the base station 210B. When the transmitter 120T is in an RRC idle state, the transmitter 120T may transmit an RRC setup request (RRCSetupRequest) message used to request establishment of an RRC connection. When the transmitter 120T is in an RRC inactive state, the transmitter 120T may transmit an RRC resume request (RRCResumeRequest (or RRCResumeRequest1)) message used to request resumption of a suspended RRC connection. The RRC resume request message may be a message used to perform a Radio Access Network (RAN) Notification Area (RNA) update. The message in this step may be referred to as message 3.

[0080] The receiving unit 212R of the base station 210B receives the message 3 from the UE 100. The control unit 130 of the base station 210B may execute control to establish or resume an RRC connection. When establishing or resuming an RRC connection, the base station 210B may execute the following processing.

[0081] Step S104: The transmitter 212T of the base station 210B transmits to the UE 100 a message for transitioning the UE 100 to the RRC connected state. If the transmitter 212T has received an RRC setup request message, the transmitter 212T may transmit an RRC setup message used to establish a signaling radio bearer (e.g., SRB1). If the transmitter 212T has received an RRC resume request message, the transmitter 212T may transmit an RRC resume message used to resume the interrupted RRC connection. The message in this step may be referred to as message 4.

[0082] The receiver 120R of the UE 100 (for example, the second receiver 122R used for communication with the S cell of the first network 200A) receives the message 4 from the base station 210B. Based on the reception of the message 4, the controller 130 of the UE 100 executes control to establish or resume an RRC connection.

[0083] Based on the determination result of step S102, the control unit 130 of the UE 100 may determine whether to include an early indication in a message 5 described below. If the control unit 130 determines that transmission of an early indication is permitted, the control unit 130 may include the early indication in the message 5. If the control unit 130 determines that transmission of an early indication is not permitted, the control unit 130 may not include the early indication in the message 5.

[0084] The early indication is information for notifying that the capability of the UE 100 is temporarily restricted. The early indication may be information for notifying that the capability of the UE 100 is temporarily restricted in the second network 200B due to communication with another network (e.g., the first network 200A). The early indication may be called by another name.

[0085] The early indication may be information indicating whether the capability of the UE 100 is temporarily restricted in the network (in this operation example, the second network 200B). The early indication may be information indicating that the capability of the UE 100 is temporarily restricted. The early indication may be information indicating that the capability of the UE 100 is not temporarily restricted (for example, the UE 100 has normal communication capability).

[0086] In this operation example, the control unit 130 determines that transmission of the early indication is permitted, and the early indication includes information indicating that the capability of the UE 100 is temporarily restricted in the message.

[0087] Step S105: The transmitter 120T of the UE 100 transmits a message to the base station 210B to confirm completion of the RRC connection. When the transmitter 120T receives an RRC setup message, the transmitter 120T may transmit to the base station 210B an RRC setup complete message used to confirm successful completion of RRC connection establishment. When the transmitter 120T receives an RRC resume message, the transmitter 120T may transmit to the base station 210B an RRC resume complete message used to confirm successful completion of RRC connection resume. The message in this step may be referred to as message 5.

[0088] If message 5 includes an early indication, the transmitter 120T can transmit the early indication to the second network 200B. In this operation example, the transmitter 120T transmits the early indication. For example, the transmitter 120T transmits the early indication when it determines that the random access procedure has been successfully completed. For example, the transmitter 120T may determine that the random access procedure has been successfully completed when it receives, in message 4, a PDCCH with a CRC scrambled with the C-RNTI. For example, the transmitter 120T may determine that the random access procedure has been successfully completed when it includes, in message 4, a C-RNTI with the same value as the C-RNTI transmitted in message 3 (the C-RNTI notified to the base station 210B) and an uplink grant for a new transmission. Here, message 4 is also referred to as contention resolution. That is, when the UE 100 determines that the contention resolution for the second network 200B (base station 210B) has been successfully completed, the UE 100 may determine that the random access procedure has been successfully completed.

[0089] Here, the random access procedure may be performed in the MAC layer in UE 100. That is, when the random access procedure is successfully completed, the MAC layer in UE 100 may provide (notify) information indicating the successful completion of the random access procedure to a layer higher than the MAC layer in UE 100 (e.g., the RRC layer). The RRC layer in UE 100 may transmit an early indication based on being provided with the information indicating the successful completion of the random access procedure. That is, the RRC layer in UE 100 may transmit an early indication based on being permitted to transmit an early indication and / or being provided with information indicating the successful completion of the random access procedure from a lower layer. Therefore, the RRC layer in UE 100 may include an early indication in message 5 based on being permitted to transmit an early indication and / or being provided with information indicating the successful completion of the random access procedure.

[0090] Note that the control unit 130 of the UE 100 may control the MAC layer and the RRC layer so that the above operations are performed. The control unit 130 may have a MAC processing unit that performs processing in the MAC layer as the MAC layer, and an upper layer processing unit that performs processing in an upper layer (e.g., an RRC layer) as a layer higher than the MAC layer. The MAC processing unit may be referred to as a MAC entity. The upper layer processing unit performs processing in a layer higher than the MAC layer. The upper layer processing unit may have a PDCP processing unit that performs processing in the PDCP layer and an RRC processing unit that performs processing in the RRCP layer. The PDCP processing unit may be referred to as a PDCP entity. The RRC processing unit may be referred to as an RRC entity.

[0091] The receiver 212R of the base station 210B receives the message 5 from the UE 100. The controller 214 of the base station 210B may determine, based on the received message 5, whether the capability of the UE 100 is temporarily restricted.

[0092] The control unit 214 may determine that the capability of the UE 100 is temporarily restricted when the message 5 includes information indicating that the capability of the UE 100 is temporarily restricted as an early indication. Alternatively, the control unit 214 may determine that the capability of the UE 100 is temporarily restricted when the message 5 does not include information indicating that the capability of the UE 100 is not temporarily restricted as an early indication. On the other hand, the control unit 214 may determine that the capability of the UE 100 is not temporarily restricted when the message 5 includes information indicating that the capability of the UE 100 is not temporarily restricted as an early indication. Alternatively, the control unit 214 may determine that the capability of the UE 100 is not temporarily restricted when the message 5 does not include information indicating that the capability of the UE 100 is temporarily restricted as an early indication.

[0093] The control unit 214 of the base station 210B may execute the process of step S106. For example, when the control unit 214 determines that the capability of the UE 100 is temporarily restricted, the control unit 214 may execute the process of step S106. The base station 210B may omit the process of step S106. For example, when the base station 210B determines that the capability of the UE 100 is not temporarily restricted, the control unit 214 may omit the process of step S106.

[0094] Note that, when the control unit 214 of the base station 210B determines that the capability of the UE 100 is temporarily restricted, the control unit 214 may suspend transmission of an RRC reconfiguration message until a predetermined time has elapsed. Furthermore, the control unit 214 may suspend (or stop) generation of part or all of the configuration information included in the RRC reconfiguration message until the predetermined time has elapsed. The control unit 214 may stop generation of information that should be configured based on at least the capability restriction information. Note that the predetermined time may be, for example, the time since receiving an early indication, the time since transmitting a UE capability query message (described later), or the time since receiving a UE capability information message (described later).

[0095] Step S106: The transmitter 212T of the base station 210B transmits a UE capability inquiry (UECapabilityEnquiry) message to the UE 100. The receiver 120R of the UE 100 receives the UE capability inquiry message from the base station 210B.

[0096] The UE Capability Enquiry message is a message used to request UE radio access capabilities. The message may be used to request UE radio access capabilities for NR and / or other radio access technologies (RATs).

[0097] The control unit 130 of the UE 100 may perform the following processing based on the reception of the UE capability information message.

[0098] Step S107: The transmitter 120T of the UE 100 transmits a UE capability information message to the base station 210B. The receiver 212R of the base station 210B receives the UE capability information message from the UE 100.

[0099] The UE Capability Information message is a message used to transfer the requested radio access capabilities to the network based on the reception of the UE Capability Enquiry message.

[0100] The control unit 130 of the UE 100 may include information indicating the normal capabilities of the UE 100 in the UE capability information message, rather than information indicating the capabilities of the UE 100 that are temporarily restricted.

[0101] Step S108: The transmitter 120T of the UE 100 transmits a UE Assistance Information message, which is used to indicate UE assistance information to the network, to the base station 210B. The receiver 212R of the base station 210B receives the UE assistance information message from the UE 100.

[0102] When the control unit 130 of the UE 100 is (deems) permitted to transmit the capability restriction information, the control unit 130 may include the capability restriction information in the UE assistance information message. This allows the transmission unit 120T to transmit the capability restriction information to the second network 200B when the transmission of the capability restriction information is permitted. When the control unit 130 is (deems) permitted to transmit the capability restriction information, the control unit 130 may determine that the transmission of the capability restriction information is permitted by the UE assistance information message.

[0103] On the other hand, if the control unit 130 determines that transmission of the capability restriction information is not permitted, the control unit 130 does not need to include the capability restriction information in the UE assistance information message. That is, the control unit 130 does not need to start transmitting the UE assistance information message including the capability restriction information. Therefore, the control unit 130 does not need to execute this step.

[0104] The capability restriction information may indicate temporarily restricted capabilities of the UE 100. The capability restriction information may indicate, for example, information available in another network (for example, the first network 200A) (for example, information unavailable in the second network 200B) or information available in the second network 200B. The information available and / or unavailable in the second network 200B may be, for example, at least any of information on secondary cells, information on component carriers, information on frequencies, and information on the number of transceivers (transmitters and / or receivers).

[0105] When a UE capability information message is transmitted, the capability restriction information may indicate a difference between the capability of the UE 100 indicated by the UE capability information message and the temporarily restricted capability of the UE 100. Note that the capability restriction information may indicate information indicating that the temporary restriction has been released.

[0106] Step S109: The transmission unit 212T of the base station 210B transmits an RRC reconfiguration message for modifying the RRC connection to the UE 100. The reception unit 120R of the UE 100 receives the RRC reconfiguration message from the base station 210B.

[0107] The control unit 214 of the base station 210B may generate some or all of the configuration information to be included in the RRC reconfiguration message, based on the capability restriction information received from the UE 100. The control unit 214 includes the configuration information in the RRC reconfiguration message.

[0108] The control unit 130 of the UE 100 executes control to establish or resume the RRC connection based on the configuration information included in the RRC reconfiguration message. When the RRC connection reconfiguration is successfully completed, the control unit 130 of the UE 100 may execute the following process.

[0109] Step S110: The transmitter 120T of the UE 100 transmits an RRC reconfiguration complete (RRCReconfigurationComplete) message used to confirm successful completion of the RRC connection reconfiguration to the base station 210B. The receiver 212R of the base station 210B receives the RRC reconfiguration complete from the UE 100.

[0110] As described above, the transmitter 212T of the base station 210B transmits a message to the UE 100 to enable the UE 100 to determine whether or not transmission of capability restriction information is permitted when the capability of the UE 100 in the second network 200B is temporarily restricted due to communication with another network (e.g., the first network 200A). The receiver 120R of the UE 100 receives a message from the second network 200B when the capability of the UE 100 in the second network 200B is temporarily restricted due to communication with the first network 200A. The control unit 130 of the UE 100 determines, based on the message, whether or not transmission of capability restriction information related to the temporarily restricted capability of the UE 100 is permitted. When transmission of the capability restriction information is permitted, the transmitter 120T of the UE 100 transmits the capability restriction information to the second network 200B. As a result, the UE 100 transmits the capacity restriction information after determining whether or not transmission of the capacity restriction information is permitted based on a message from the second network 200B, and therefore the UE 100 does not freely transmit the capacity restriction information without being restricted by the second network 200B. As a result, the UE 100 can appropriately transmit the capacity restriction information.

[0111] Furthermore, the receiver 120R of the UE 100 may receive the message before the completion of the random access procedure with the second network 200B. This allows the UE 100 to determine whether or not transmission of the capability restriction information is permitted before the RRC connection with the second network 200B is established or resumed. That is, the UE 100 can make the determination at an earlier stage than when making the determination after the RRC connection is established or resumed.

[0112] Furthermore, the transmitter 120T of the UE 100 may transmit an early indication to the second network 200B, notifying the second network 200B that the capability of the UE 100 is temporarily restricted. The receiver 120R may receive a message before transmitting the early indication. This allows the UE 100 to determine whether transmission of capability restriction information is permitted before transmitting the early indication. If transmission of capability restriction information is not permitted, the UE 100 may cancel transmission of the early indication. This prevents the UE 100 from needlessly transmitting the early indication (and the capability restriction information), thereby enabling radio resources to be saved.

[0113] The message may also include early indication determination information for determining whether transmission of the early indication is permitted. When determining that transmission of the early indication is permitted based on the early indication determination information, the control unit 130 may determine that transmission of the capacity restriction information is permitted. This allows the UE 100 to determine whether transmission of the capacity restriction information is permitted, even without receiving information that explicitly indicates that transmission of the capacity restriction information is permitted. As a result, the amount of information transmitted between the UE 100 and the base station 210B can be reduced, thereby enabling radio resources to be saved.

[0114] Furthermore, the message may include an SIB transmitted from the second network 200B by broadcast. This allows the UE 100 to determine whether or not transmission of the capability restriction information is permitted even before transitioning to the RRC connected state. For example, when transmission of the capability restriction information is not permitted, the UE 100 suspends connection to the second network 200B until the temporary restriction on the capability of the UE 100 is released, thereby making it possible to prevent the UE 100 from becoming over capacity due to communication with the first and second networks.

[0115] (2) Second Operation Example With reference to Fig. 8, the second operation example will be described, focusing on differences from the above-described operation example. Description of operations similar to those in the above-described operation example may be omitted. In this operation example, the UE 100 determines whether transmission of the capability restriction information is permitted based on the capability restriction determination information included in the message 4.

[0116] Step S201: Step S201 is similar to step S101.

[0117] Step S202: As in step S102, the control unit 130 of the UE 100 determines whether or not transmission of an early indication is permitted. The control unit 130 of the UE 100 determines whether or not transmission of an early indication is permitted based on the EI determination information. On the other hand, in this operation example, the control unit 130 of the UE 100 does not determine whether or not transmission of capability restriction information is permitted based on the EI determination information.

[0118] Step S203 is similar to step S103.

[0119] Step S204: The transmitter 212T of the base station 210B transmits message 4 to the UE 100, similar to step S104. The receiver 120R of the UE 100 receives message 4 from the base station 210B. The receiver 120R receives message 4 before the RA procedure is completed. The receiver 120R also receives message 4 before the transmission of an early indication. Note that message 4 is an individual RRC message received from the second network 200B during the random access procedure.

[0120] The control unit 214 of the base station 210B includes capability restriction determination information (hereinafter referred to as CR determination information) in the message 4. The CR determination information may be any of the following information: Information indicating that (the base station and / or cell) permits (or instructs) the transmission of capability restriction information Information indicating that (the base station and / or cell) does not permit (or instructs) the transmission of capability restriction information Information indicating whether (the base station and / or cell) permits (or instructs) the transmission of capability restriction information Information indicating (the base station and / or cell) permits (or instructs) the transmission of capability restriction information by a UE assistance information message Information indicating (the base station and / or cell) does not permit (or instruct) the transmission of capability restriction information by a UE assistance information message Information indicating whether (the base station and / or cell) permits (or instructs) the transmission of capability restriction information by a UE assistance information message

[0121] The CR determination information may be, for example, configuration information for configuring provision of capability restriction information. The CR determination information may be configuration information for configuring transmission of a UE assistance information message. The CR configuration information may be information equivalent to configuration information for configuring transmission of a UE assistance information message, which is included in OtherConfig in the RRC reconfiguration message.

[0122] Step S205: The control unit 130 of the UE 100 determines whether or not transmission of the capability restriction information is permitted based on the capability restriction determination information. The control unit 130 may determine whether or not transmission of the capability restriction information is permitted, similar to the determination of the early indication.

[0123] For example, the control unit 130 may determine that the transmission of the capability restriction information is permitted when the message 4 includes information indicating that the transmission of the capability restriction information is permitted. Alternatively, the control unit 130 may determine that the transmission of the capability restriction information is permitted when the message 4 does not include information indicating that the transmission of the capability restriction information is not permitted, that is, when the message 4 does not include CR determination information.

[0124] On the other hand, if message 4 includes information indicating that transmission of the capability restriction information is not permitted, control unit 130 may determine that transmission of the capability restriction information is not permitted. Alternatively, if message 4 does not include information indicating that transmission of the capability restriction information is permitted, that is, if message 4 does not include CR determination information, control unit 130 may determine that transmission of the capability restriction information is not permitted.

[0125] Furthermore, control unit 130 may determine that transmission of capacity restriction information is permitted when it receives setting information for setting provision of capacity restriction information, i.e., when message 4 includes the setting information. Control unit 130 may determine that transmission of capacity restriction information is not permitted when it does not receive setting information for setting provision of capacity restriction information, i.e., when message 4 does not include the setting information.

[0126] Based on the determination result, the control unit 130 of the UE 100 may determine whether to include an early indication in the message 5. When the control unit 130 determines that the transmission of the capability restriction information is permitted, the control unit 130 may include the early indication in the message 5. When the control unit 130 determines that the transmission of the early indication is not permitted, the control unit 130 may not include the early indication in the message 5.

[0127] Steps S206 to S211 are similar to steps S105 to S110.

[0128] As described above, the message may include capacity restriction determination information for determining whether transmission of the capacity restriction information is permitted. The control unit 130 of the UE 100 may determine whether transmission of the capacity restriction information is permitted based on the capacity restriction determination information. This allows the second network 200B to explicitly indicate to the UE 100 whether transmission of the capacity restriction information is permitted, thereby appropriately controlling transmission of the capacity restriction information of the UE 100.

[0129] Furthermore, the message may be an individual RRC message received from the second network 200B during the random access procedure. This allows the second network 200B to individually grant permission to transmit the capability restriction information to the UE 100, thereby enabling flexible control of the transmission of the capability restriction information.

[0130] (3) Third Operation Example With reference to Fig. 9, the third operation example will be described, focusing on differences from the above-described operation example. Description of operations similar to those in the above-described operation example may be omitted. In this operation example, the UE 100 determines whether transmission of capability restriction information is permitted based on capability restriction determination information included in the RRC reconfiguration message.

[0131] Steps S301 to S305 are similar to steps S201 to S205.

[0132] Step S306: The transmitter 212T of the base station 210B transmits an RRC reconfiguration message to the UE 100. The receiver 120R of the UE 100 receives the RRC reconfiguration message from the base station 210B.

[0133] Note that UE 100 has completed the RA procedure by transmitting message 5. Therefore, receiving unit 120R receives the RRC reconfiguration message after the completion of the RA procedure. UE 100 receives the RRC reconfiguration message after transitioning from the RRC idle state or the RRC inactive state to the RRC connected state due to the completion of the RA procedure.

[0134] When the control unit 214 of the base station 210B determines that the capability of the UE 100 is temporarily restricted based on the early indication that may be included in the message 5, the control unit 214 may determine whether to include CR determination information in the RRC reconfiguration message to indicate whether transmission of capability restriction information is permitted. When transmission of capability restriction information is permitted, the control unit 214 may include the CR determination information in the RRC reconfiguration message.

[0135] In addition to the information exemplified above, the CR determination information may be, for example, configuration information for configuring the transmission of a UE assistance information message, which is included in OtherConfig in the RRC reconfiguration message.

[0136] When the control unit 214 permits transmission of the capability restriction information, the control unit 214 may not include in the RRC reconfiguration message at least information that should be set based on the capability restriction information (hereinafter, sometimes referred to as specific setting information). The control unit 214 may set the specific setting information to a null value (or an empty value). The control unit 214 may not include information other than the CR determination information and mandatory information.

[0137] The specific setting information may be information whose setting may be affected by the capacity restriction information. The specific setting information may be, for example, at least one of information for setting dual connectivity operation and information for setting carrier aggregation operation.

[0138] When the capability of the UE 100 in the second network 200B is temporarily restricted due to communication with the first network 200A, and when the control unit 130 of the UE 100 receives an RRC reconfiguration message from the second network 200B before transmitting capability restriction information to the second network 200B, the control unit 130 may ignore, discard, clear, or deactivate specific configuration information included in the RRC reconfiguration message. For example, the control unit 130 may not apply information other than the CR determination information included in the RRC reconfiguration message. The control unit 130 may ignore, discard, clear, or deactivate information other than the CR determination information.

[0139] Step S307 is similar to step S205.

[0140] The control unit 130 of the UE 100 may determine whether transmission of capability restriction information is permitted based on the CR determination information. When transmission of capability restriction information is permitted, the control unit 130 may ignore, discard, clear, or deactivate specific configuration information included in the RRC reconfiguration message. When transmission of capability restriction information is permitted, the control unit 130 may ignore, discard, clear, or deactivate information other than the CR determination information.

[0141] Steps S308 to S312 are similar to steps S207 to S211.

[0142] As described above, the receiver 120R of the UE 100 may receive, as a message, an RRC reconfiguration message including CR determination information for determining whether transmission of capability restriction information is permitted after the UE 100 transitions to the RRC connected state in the second network. The control unit 130 may determine whether transmission of capability restriction information is permitted based on the capability restriction determination information. As a result, when the UE 100 transitions to the RRC connected state, the UE 100 no longer exchanges CR determination information, thereby reducing the impact on existing systems (and technical specifications). In particular, since the transmission of the UE assistance information message is information configured by the RRC reconfiguration message, if the CR determination information is configuration information for configuring transmission of the UE assistance information message, which is included in OtherConfig in the RRC reconfiguration message, the impact on existing systems (and technical specifications) can be reduced.

[0143] Furthermore, when the capability of the UE 100 in the second network 200B is temporarily restricted by communication with the first network 200A, and when the control unit 130 receives an RRC reconfiguration message from the second network 200B before transmitting the capability restriction information to the second network 200B, the control unit 130 may ignore or discard information that should be set based on the capability restriction information among the information included in the RRC reconfiguration message. This allows the UE 100 to avoid applying information that does not take into account the capability restriction information, thereby making it possible to prevent the UE 100 from becoming over capacity due to communication with the first and second networks.

[0144] (4) Fourth Operation Example With reference to Fig. 10, a fourth operation example will be described, focusing on differences from the above-described operation example. Description of operations similar to the above-described operation example may be omitted. In this operation example, an operation when the UE 100 receives an RRC reconfiguration message will be described.

[0145] Step S401: The control unit 130 of the UE 100 determines whether the capability of the UE 100 is temporarily restricted. For example, the control unit 130 may determine that the capability of the UE 100 is temporarily restricted when the UE 100 is performing communication with a network 200 different from the network that received the RRC reconfiguration message (hereinafter referred to as the second network 200B). On the other hand, the control unit 130 may determine that the capability of the UE 100 is temporarily restricted when the UE 100 is performing communication only with the second network 200B that received the RRC reconfiguration message.

[0146] The control unit 130 executes the process of step S402 when the capability of the UE 100 is temporarily restricted. On the other hand, the control unit 130 executes the process of step S404 when the capability of the UE 100 is not temporarily restricted.

[0147] Step S402: The control unit 130 determines whether or not the capacity restriction information has not yet been transmitted. If the capacity restriction information has not yet been transmitted, the control unit 130 executes the process of step S403. If the capacity restriction information has already been transmitted, the control unit 130 executes the process of step S404.

[0148] Step S403: The control unit 130 ignores or discards some or all of the information in the RRC reconfiguration message. The control unit 130 may clear or deactivate the information. For example, as in the third operation example, the control unit 130 may ignore or discard specific setting information (information that should be set based on capacity restriction information). If the RRC reconfiguration message does not include CR determination information, the control unit 130 may ignore or discard all of the information.

[0149] Note that the control unit 130 may activate the deactivated information after receiving an RRC reconfiguration message after transmitting the capability restriction information.

[0150] Step S404: The control unit 130 applies the information in the RRC reconfiguration message.

[0151] As described above, when the capability of the UE 100 in the second network 200B is temporarily restricted due to communication with the first network 200A, and when the control unit 130 receives an RRC reconfiguration message from the second network 200B before transmitting the capability restriction information to the second network 200B, the control unit 130 may ignore or discard information that should be set based on the capability restriction information among the information included in the RRC reconfiguration message. This allows the UE 100 to avoid applying information that does not take into account the capability restriction information, thereby making it possible to prevent the UE 100 from becoming over capacity due to communication with the first and second networks.

[0152] (5) Fifth Operation Example With reference to Fig. 11, the fifth operation example will be described, focusing on differences from the above-described operation examples. Description of operations similar to those in the above-described operation examples may be omitted. In this operation example, an operation in which the UE 100 is controlled by a prohibition timer will be described.

[0153] Step S501: The transmitter 212T of the base station 210B may transmit a timer value related to the transmission of capacity restriction information (hereinafter, may be referred to as a prohibition timer value) to the UE 100. The receiver 120R of the UE 100 may receive the prohibition timer value from the base station 210B.

[0154] The control unit 214 of the base station 210B may, for example, include the prohibit timer value in a system information block (SIB1 or another SIB). Furthermore, the control unit 214 may, for example, include the prohibit timer value in a message for determining whether transmission of capability restriction information is permitted. The control unit 214 may include the prohibit timer value in the CR determination information. The control unit 214 may include the prohibit timer value in configuration information for configuring transmission of a UE assistance information message. The control unit 214 may include the prohibit timer value as the CR determination information. When the prohibit timer value is included, the control unit 130 of the UE 100 may determine that transmission of capability restriction information is permitted.

[0155] The prohibition timer value may indicate a value set in a prohibition timer (described later). The prohibition timer value may be a timer value for prohibiting transmission of capacity restriction information for a certain period of time. Note that the prohibition timer value may be a fixed value that is predefined (by technical specifications).

[0156] Step S502: When transmitting the capacity restriction information, the control unit 130 sets the prohibition timer to a prohibition timer value. When transmitting the capacity restriction information, the control unit 130 starts the prohibition timer to which the prohibition timer value has been set.

[0157] Step S503: The control unit 130 determines whether or not the transmission of capability restriction information has been triggered. The control unit 130 of the UE 100 whose capability is temporarily restricted may determine that the transmission of capability restriction information has been triggered, for example, when it is necessary to transition to an RRC connected state in the second network 200B. The control unit 130 may determine that the transmission of capability restriction information has been triggered, for example, when an RRC connection is established or resumed. Otherwise, the control unit 130 may determine that the transmission of capability restriction information has not been triggered. Note that the control unit 130 may determine whether or not a transmission condition for the capability restriction information has been satisfied.

[0158] Step S504: The control unit 130 determines whether the prohibition timer is running. If the prohibition timer is not running, the control unit 130 may execute the process of step S504. If the prohibition timer is running, the control unit 130 may execute the process of step S503. Note that if the prohibition timer is running, the control unit 130 may end the process. Therefore, while the prohibition timer is running, the control unit 130 prohibits the transmission of a new UE assistance information message including capability restriction information.

[0159] Step S505: The control unit 130 may determine whether the capabilities of the UE 100 (hereinafter, sometimes referred to as the capabilities of the current UE 100) differ from the capabilities of the UE 100 indicated in the previous capability restriction information. For example, if the capabilities of the UE 100 have been updated since the previous capability restriction information, the control unit 130 determines that the capabilities of the current UE 100 differ from the capabilities of the UE 100 indicated in the previous capability restriction information. If communication with the first network 200A has been terminated after the previous capability restriction information, the control unit 130 may determine that the capabilities of the current UE 100 differ from the capabilities of the UE 100 indicated in the previous capability restriction information. On the other hand, for example, if the capabilities of the UE 100 have not been updated since the previous capability restriction information, the control unit 130 determines that the capabilities of the current UE 100 are the same as the capabilities of the UE 100 indicated in the previous capability restriction information. If communication with the first network 200A is maintained after the previous capacity restriction information, the control unit 130 determines that the current capacity of the UE 100 is the same as the capacity of the UE 100 indicated in the previous capacity restriction information.

[0160] If the current capability of UE 100 is different from the capability of UE 100 indicated in the previous capability restriction information, control unit 130 executes the process of step S506. On the other hand, if the current capability of UE 100 is the same as the capability of UE 100 indicated in the previous capability restriction information, control unit 130 ends the process. Therefore, after transmitting the previous capability restriction information, control unit 130 can perform control to stop transmitting new capability restriction information until the temporary restriction on the capability of UE 100 indicated in the previous capability restriction information is changed.

[0161] The control unit 130 may execute this step when resuming the RRC connection, for example, or may skip this step when in the RRC idle state.

[0162] Step S506: The control unit 130 controls the transmission unit 120T to transmit the capability restriction information. The transmission unit 120T transmits the capability restriction information. The transmission unit 120T may transmit a UE assistance information message including the capability restriction information.

[0163] As described above, the message may include a prohibition timer value related to the transmission of the capability restriction information. When transmitting a UE assistance information message including the capability restriction information, the control unit 130 may start a prohibition timer set to a value indicated by the prohibition timer information. The control unit 130 may prohibit the transmission of a new UE assistance information message including the capability restriction information while the prohibition timer is running. This can prevent the UE 100 from frequently transmitting the capability restriction information, thereby reducing waste of radio resources.

[0164] Furthermore, after transmitting the capacity restriction information, the control unit 130 may perform control to stop transmission of new capacity restriction information until the temporary restriction on the capacity of the UE 100 indicated by the capacity restriction information is changed. This makes it possible to prevent the UE 100 from continuously transmitting capacity restriction information with the same content, thereby suppressing waste of radio resources.

[0165] (6) Sixth Operation Example With reference to Figures 12 and 13, the sixth operation example will be described, focusing on differences from the above-described operation examples. Description of operations similar to those in the above-described operation examples may be omitted. In this operation example, an operation in which the UE 100 transmits capability restriction information before a certain time has elapsed will be described.

[0166] Step S601: The transmitter 212T of the base station 210B may transmit a timer value (hereinafter, sometimes referred to as the restriction timer value) to be set in a timer that counts the time limit until transmission of capacity restriction information (hereinafter, sometimes referred to as the restriction timer), to the UE 100. The receiver 120R of the UE 100 may receive the restriction timer value from the base station 210B.

[0167] The control unit 214 of the base station 210B may, for example, include the prohibition timer value in a system information block (SIB1 or another SIB). Furthermore, the control unit 214 may, for example, include the restriction timer value in a message for determining whether transmission of capability restriction information is permitted. The control unit 214 may include the restriction timer value in the CR determination information. The control unit 214 may include the restriction timer value in configuration information for configuring transmission of a UE assistance information message. The control unit 214 may include the restriction timer value as the CR determination information. When the restriction timer value is included, the control unit 130 of the UE 100 may determine that transmission of capability restriction information is permitted.

[0168] The limit timer value may indicate a value set in a limit timer (described later). Note that the limit timer value may also be a fixed value that is predefined (by technical specifications).

[0169] Step S602: The control unit 130 sets the restriction timer to a restriction timer value. The control unit 130 starts the restriction timer to which the restriction timer value has been set. The control unit 130 may start the restriction timer, for example, when transmitting an early indication. If the control unit 130 has received a UE capability query message, the control unit 130 may start the restriction timer when transmitting a UE capability information message.

[0170] When there is a plan to transmit capability restriction information, the control unit 130 may set the restriction timer to a restriction timer value. When there is no plan to transmit capability restriction information, the control unit 130 may not set the restriction timer to a restriction timer value even if an early indication and / or a UE capability information message is transmitted.

[0171] Step S603: The control unit 130 controls the transmission of the capacity restriction information before the restriction timer expires. The control unit 130 may control the transmission of the capacity restriction information while the restriction timer is running. This allows the control unit 130 to manage the time limit for transmitting the capacity restriction information. Therefore, the transmission unit 120T can transmit the capacity restriction information to the second network 200B before a predetermined time has elapsed since the early indication was transmitted.

[0172] In addition, the control unit 130 may control the transmission unit 120T to immediately transmit the capability restriction information (a UE assistance information message including the capability restriction information) after transmitting the early indication. When such an operation is performed, the control unit 130 does not need to manage the restriction timer.

[0173] Next, the operation of the base station 210B will be described. The base station 210B may perform the following operations when establishing or resuming an RRC connection with the UE 100.

[0174] Step S621: The control unit 214 of the base station 210B determines whether or not an early indication has been received from the UE 100. If the control unit 214 has received the early indication from the UE 100, the control unit 214 executes the process of step S622. On the other hand, if the control unit 214 has not received the early indication from the UE 100, the control unit 214 may terminate the process. In this case, the control unit 214 may determine that the capability of the UE 100 is not temporarily restricted, and may execute control to establish or resume an RRC connection.

[0175] Step S622: The control unit 214 determines whether or not capability restriction information has been received before a predetermined time has elapsed. If the control unit 214 has not received the capability restriction information before the predetermined time has elapsed, the control unit 214 executes the process of step S623. On the other hand, if the control unit 214 has received the capability restriction information before the predetermined time has elapsed, the control unit 214 may terminate the process. In this case, the control unit 214 may execute control to establish or resume an RRC connection based on the capability restriction information from the UE 100.

[0176] The control unit 214 may calculate the predetermined time based on the restriction timer value when transmitting the restriction timer value to the UE 100. The control unit 214 may calculate the predetermined time based on a fixed value that is defined in advance.

[0177] Step S623: If the control unit 214 does not receive capacity restriction information from the communication device until a predetermined time has elapsed since receiving the early indication, the control unit 214 executes the following process.

[0178] First, the control unit 214 may execute a process of releasing a connection (for example, an RRC connection) with the UE 100. The control unit 214 may execute a process for the UE 100 to transition from the RRC connected state to the RRC idle state.

[0179] Second, the control unit 214 determines the configuration information to be set in the UE 100, assuming that the capabilities of the UE 100 are the lowest. The control unit 214 may determine the configuration information based only on the capabilities that the UE 100 is currently using for communication with the second network 200B, for example. The control unit 214 may determine the configuration information so that the UE 100 does not use any frequency, cell, and / or component carrier other than those currently being used by the UE 100. The control unit 214 may determine the configuration information assuming that the UE 100 has only one receiving unit and / or transmitting unit. The control unit 214 transmits the determined configuration information to the UE 100.

[0180] Thirdly, the control unit 214 may determine the configuration information assuming that the capability of the UE 100 is not temporarily restricted (i.e., the capability is the normal (maximum) capability of the UE 100).

[0181] As described above, the transmitter 120T of the UE 100 may transmit the early indication to the second network. The transmitter 120T may transmit the capacity restriction information to the second network 200B before the time limit has elapsed since the early indication was transmitted. This prevents the time until the network 200 receives the capacity restriction information from exceeding the time limit. For example, when the network 200 suspends generation of the configuration information for the UE 100 until it receives the capacity restriction information, it is possible to prevent a delay in the time until the configuration information is generated.

[0182] Furthermore, the receiving unit 120R of the UE 100 may receive, from the second network 200B, a timer value to be set in a timer that counts the time limit. This allows the second network 200B to control the time limit for transmitting the capacity restriction information.

[0183] Furthermore, the receiver 212R of the base station 210B may receive an early indication from the UE 100. If the controller 214 does not receive capacity restriction information from the UE 100 until a predetermined time has elapsed since the reception of the early indication, the controller 214 may execute a process to release the connection with the UE 100. Here, if the base station 210B does not receive capacity restriction information even after a predetermined time has elapsed since the UE 100 transmitted the early indication, it is assumed that, for example, the communication environment of the UE 100 is poor or a malfunction has occurred in the UE 100 itself. Therefore, by executing a process to release the connection with the UE 100, the base station 210B can avoid wasting resources for the UE 100 that is unable to communicate properly.

[0184] Furthermore, the receiver 212R may receive an early indication from the UE 100. If the controller 214 does not receive capability restriction information from the UE 100 until a predetermined time has elapsed since the receiver 214 received the early indication, the controller 214 may determine information to be set for the UE 100, assuming that the capability of the UE 100 is at the lowest. This makes it possible to avoid unnecessarily reserving radio resources for the UE 100 while ensuring (a minimum level of) communication with the second network 200B.

[0185] [Other Embodiments] In the above-described embodiment, the UE 100 has been described as having two transceivers, but this is not limiting. The UE 100 may have, for example, three or more transceivers. The UE 100 may have only one transceiver if it is capable of communicating with multiple networks using multiple subscriber identity modules with one transceiver.

[0186] In the above-described operation examples, the RRC setup procedure and the RRC resume procedure have been described as examples, but the present invention is not limited to these. For example, an RRC re-establishment procedure may be performed. The establishment of an RRC connection may be re-establishment of an RRC connection. Therefore, in the above description, the RRC setup request message may be, for example, an RRC connection request message used to request re-establishment of an RRC connection. The RRC setup message may be, for example, an RRC re-establishment message used to re-establish SRB1. The RRC setup complete message may be an RRC re-establishment complete message used to confirm successful completion of the RRC connection re-establishment.

[0187] In the first operation example described above, the case where the early indication determination information (EI determination information) is included in the SIB has been exemplified, but the present invention is not limited to this. The EI determination information may be included in an individual RRC message (e.g., an RRC setup message, an RRC resume message, and / or an RRC re-establishment message) received during the RA procedure.

[0188] Furthermore, in the second and third operation examples, the CR decision information is included in an individual RRC message, but this is not limiting. The CR decision information may be included in a system information block. Furthermore, in each of the above operation examples, the CR decision information may be, for example, the following information: - Information indicating that the base station and / or cell supports the capability restriction information - Information indicating that the base station and / or cell does not support the capability restriction information - Information indicating whether the base station and / or cell supports the capability restriction information

[0189] Furthermore, in each of the above-described operation examples, the determination of UE 100 (for example, step S102 and / or step S205) may be performed in a different order.

[0190] In addition, in each of the above-described operation examples, the UE 100 transmits the capability restriction information to the second network 200B by a UE assistance information message, but the capability restriction information may be transmitted by another message. For example, the UE 100 may transmit the capability restriction information by a UE capability information message.

[0191] The operation sequences (and operation flows) in the above-described embodiments do not necessarily have to be executed in chronological order according to the order depicted in the flow diagrams or sequence diagrams. For example, steps in the operations may be executed in an order different from that depicted in the flow diagrams or sequence diagrams, or may be executed in parallel. Some steps in the operations may be deleted, or additional steps may be added to the processing. The operation sequences (and operation flows) in the above-described embodiments may be executed independently, or two or more operation sequences (and operation flows) may be executed in combination. For example, some steps in one operation flow may be added to another operation flow, or some steps in one operation flow may be replaced with some steps in another operation flow.

[0192] In the above-described embodiment, an NR-based mobile communication system has been described as an example of the mobile communication system 1. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system compliant with the TS of either LTE or another generation system (e.g., the sixth generation) of the 3GPP standard. The base station 210 may be an eNB that provides E-UTRA user plane and control plane protocol termination for the UE 100 in LTE. The mobile communication system 1 may be a system compliant with the TS of a standard other than the 3GPP standard. The base station 210 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

[0193] A program may be provided that causes a computer to execute each process performed by the UE 100 or the base station 210. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM (Compact Disk Read Only Memory) or a DVD-ROM (Digital Versatile Disc Read Only Memory). Furthermore, circuits that execute each process performed by the UE 100 or the base station 210 may be integrated, and at least a part of the UE 100 or the base station 210 may be configured as a semiconductor integrated circuit (chip set, SoC (System On Chip)).

[0194] In the above-described embodiments, "transmit" may mean performing processing at least one layer in a protocol stack used for transmission, or may mean physically transmitting a signal wirelessly or via a wired connection. Alternatively, "transmit" may mean a combination of performing processing at least one layer and physically transmitting a signal wirelessly or via a wired connection. Similarly, "receive" may mean performing processing at least one layer in a protocol stack used for reception, or may mean physically receiving a signal wirelessly or via a wired connection. Alternatively, "receive" may mean a combination of processing at least one layer and physically receiving a signal wirelessly or via a wired connection. Similarly, "obtain / acquire" may mean obtaining information from stored information, obtaining information from information received from another node, or obtaining information by generating the information. Similarly, the terms "based on" and "depending on / in response to" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." Similarly, "include" and "comprise" do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Similarly, in this disclosure, "or" does not mean an exclusive or, but rather a logical or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements.Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0195] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0196] (Additional Notes) Additional notes will be given regarding the features of the above-described embodiment.

[0197] (Supplementary Note 1) A communication device comprising: a receiving unit that receives a message from the second network when the capabilities of the communication device in the second network are temporarily restricted due to communication with the first network; a control unit that determines whether transmission of capability restriction information regarding the temporarily restricted capabilities of the communication device is permitted based on the message; and a transmitting unit that transmits the capability restriction information to the second network when transmission of the capability restriction information is permitted.

[0198] (Supplementary Note 2) The communication device according to Supplementary Note 1, wherein the receiving unit receives the message before completion of a random access procedure with the second network.

[0199] (Supplementary Note 3) The communication device according to Supplementary Note 1 or 2, wherein the transmitter transmits an early indication to the second network notifying that capabilities of the communication device are temporarily restricted in the second network, and the receiver receives the message before transmitting the early indication.

[0200] (Supplementary Note 4) The communication device according to Supplementary Note 3, wherein the message includes early indication determination information for determining whether transmission of the early indication is permitted, and the control unit determines that transmission of the capacity restriction information is permitted when determining that transmission of the early indication is permitted based on the early indication determination information.

[0201] (Supplementary Note 5) The communication device described in any one of Supplementary Notes 1 to 4, wherein the message includes capacity restriction determination information for determining whether or not transmission of the capacity restriction information is permitted, and the control unit determines whether or not transmission of the capacity restriction information is permitted based on the capacity restriction determination information.

[0202] (Supplementary Note 6) The communication device according to any one of Supplementary Notes 1 to 5, wherein the message includes a system information block transmitted from the second network by broadcast.

[0203] (Supplementary Note 7) The communication device according to any one of Supplementary Notes 2 to 4, wherein the message is a dedicated Radio Resource Control (RRC) message received from the second network during the random access procedure.

[0204] (Supplementary Note 8) The communication device according to any one of Supplementary Notes 1 to 7, wherein the receiving unit receives, as the message, an RRC reconfiguration message including capability restriction determination information for determining whether or not transmission of the capability restriction information is permitted after the communication device transitions to a Radio Resource Control (RRC) connected state in the second network, and the control unit determines whether or not transmission of the capability restriction information is permitted based on the capability restriction determination information.

[0205] (Supplementary Note 9) The communication device according to any one of Supplementary Notes 1 to 7, wherein, when a capability of the communication device in the second network is temporarily restricted due to communication with the first network and the control unit receives a radio resource control (RRC) reconfiguration message from the second network before transmitting the capability restriction information to the second network, the control unit ignores or discards information included in the RRC reconfiguration message that should be configured based on the capability restriction information.

[0206] (Supplementary Note 10) The communication device according to any one of Supplementary Notes 1 to 7, wherein the message includes a prohibition timer value related to transmission of the capability restriction information, and the control unit starts a prohibition timer set to the prohibition timer value when transmitting a user equipment (UE) assistance information message including the capability restriction information, and prohibits transmission of a new UE assistance information message including the capability restriction information while the prohibition timer is running.

[0207] (Supplementary Note 11) The communication device described in any one of Supplementary Notes 1 to 7, wherein after transmitting the capacity restriction information, the control unit performs control to suspend transmission of new capacity restriction information until a temporary restriction on the capacity of the communication device indicated in the capacity restriction information is changed.

[0208] (Supplementary Note 12) The communication device according to any one of Supplementary Notes 1 to 7, wherein the transmitter transmits an early indication to the second network notifying the second network that the capability of the communication device is temporarily restricted, and the transmitter transmits the capability restriction information to the second network before a time limit has elapsed since the early indication was transmitted.

[0209] (Supplementary Note 13) The communication device according to Supplementary Note 12, wherein the receiving unit receives, from the second network, a timer value to be set in a timer that counts the time limit.

[0210] (Supplementary Note 14) A base station of a second network that communicates with a communication device that can communicate with a first network and a second network using a plurality of subscriber identity modules, the base station comprising: a transmitter that transmits a message to the communication device, when the capability of the communication device in the second network is temporarily restricted due to communication with the first network, for the communication device to determine whether or not transmission of capability restriction information related to the temporarily restricted capability of the communication device is permitted.

[0211] (Supplementary Note 15) The base station according to Supplementary Note 14, comprising: a receiving unit that receives from the communication device an early indication notifying that the capability of the communication device is temporarily restricted in the second network; and a control unit that executes processing to release the connection with the communication device if the capability restriction information is not received from the communication device within a predetermined time period after receiving the early indication.

[0212] (Supplementary Note 16) The base station according to Supplementary Note 14, comprising: a receiving unit that receives from the communication device an early indication notifying that the capability of the communication device is temporarily restricted in the second network; and a control unit that, if the capability restriction information is not received from the communication device within a predetermined time period after receiving the early indication, determines that the capability of the communication device is at its lowest and determines information to be set in the communication device.

[0213] (Supplementary Note 17) A communication method executed in a communication device capable of communicating with a first network and a second network using a plurality of subscriber identity modules, comprising: receiving a message from the second network when the capability of the communication device in the second network is temporarily restricted due to communication with the first network; determining, based on the message, whether transmission of capability restriction information related to the temporarily restricted capability of the communication device is permitted; and transmitting the capability restriction information to the second network when transmission of the capability restriction information is permitted. (Supplementary Note 18) A communication device that communicates with a first network and a second network using a plurality of subscriber identity modules, comprising: a receiver that receives a Radio Resource Control (RRC) reconfiguration message from the second network; and a controller that determines, based on the RRC reconfiguration message, whether to transmit capability restriction information related to the temporarily restricted capability of the communication device. (Supplementary Note 19) The communication device according to Supplementary Note 18, wherein the RRC reconfiguration message includes configuration information related to configuration of provision of the capability restriction information, and the controller determines, based on the configuration information, whether to transmit the capability restriction information. (Supplementary Note 20) The communication device according to Supplementary Note 18 or 19, wherein the RRC reconfiguration message includes information indicating whether to instruct transmission of the capacity restriction information, and the control unit determines whether to transmit the capacity restriction information based on the information indicating whether to instruct transmission of the capacity restriction information. (Supplementary Note 21) The communication device according to Supplementary Note 20, further comprising a transmitting unit that transmits the capacity restriction information to the second network when the information indicating whether to instruct transmission of the capacity restriction information instructs transmission of the capacity restriction information.(Supplementary Note 22) The communication device according to any one of Supplementary Notes 18 to 21, wherein the receiving unit receives the RRC reconfiguration message including a prohibition timer value related to transmission of the capability restriction information, and the control unit starts a prohibition timer having the prohibition timer value set based on transmission of a user equipment (UE) assistance information message including the capability restriction information, and prohibits transmission of a new UE assistance information message including the capability restriction information while the prohibition timer is running. (Supplementary Note 23) The communication device according to any one of Supplementary Notes 18 to 22, wherein the control unit controls transmission of new capability restriction information when a temporary restriction on the capability of the communication device indicated by the capability restriction information is changed. (Supplementary Note 24) The communication device according to any one of Supplementary Notes 18 to 23, wherein the receiving unit receives from the second network a system information block including information for permitting transmission of information notifying that the capability of the communication device is temporarily restricted, the control unit determines that transmission of the information indicating that the capability of the communication device is temporarily restricted is permitted based on the information for permitting transmission of the information indicating that the capability of the communication device is temporarily restricted, which is included in the system information block, and a transmitting unit that transmits the information indicating that the capability of the communication device is temporarily restricted to the second network when transmission of the information indicating that the capability of the communication device is temporarily restricted is permitted. (Supplementary Note 25) A base station of the second network, comprising: a transmitting unit that transmits a Radio Resource Control (RRC) reconfiguration message to a communication device that communicates with a first network and the second network using a plurality of subscriber identity modules, the RRC reconfiguration message being used in the communication device to determine whether to transmit capability restriction information regarding the temporarily restricted capability of the communication device.(Supplementary Note 26) A communication method executed in a communication device that communicates with a first network and a second network using a plurality of subscriber identity modules, comprising: receiving a radio resource control (RRC) reconfiguration message from the second network; and determining, based on the RRC reconfiguration message, whether to transmit capability restriction information related to temporarily restricted capabilities of the communication device.

Claims

1. A communication device (100) that communicates with a first network (200A) and a second network (200B) using multiple subscriber identity modules, comprising: a receiving unit (120R) that receives a radio resource control (RRC) reconfiguration message from the second network; and a control unit (130) that determines whether to transmit capability restriction information regarding temporarily restricted capabilities of the communication device based on the RRC reconfiguration message.

2. The communication device according to claim 1, wherein the RRC reconfiguration message includes setting information regarding a setting for providing the capability restriction information, and the control unit determines whether or not to transmit the capability restriction information based on the setting information.

3. The communication device according to claim 1 or 2, wherein the RRC reconfiguration message includes information indicating whether or not to instruct transmission of the capability restriction information, and the control unit determines whether or not to transmit the capability restriction information based on the information indicating whether or not to instruct transmission of the capability restriction information.

4. A communication device as described in claim 3, further comprising a transmitting unit that transmits the capacity restriction information to the second network when the information indicating whether or not to instruct the transmission of the capacity restriction information instructs the transmission of the capacity restriction information.

5. The communication device according to claim 1 or 2, wherein the receiving unit receives the RRC reconfiguration message including a prohibition timer value related to the transmission of the capability restriction information, and the control unit starts a prohibition timer having the prohibition timer value set based on the transmission of a user equipment (UE) assistance information message including the capability restriction information, and prohibits the transmission of a new UE assistance information message including the capability restriction information while the prohibition timer is running.

6. The communication device according to claim 1 or 2, wherein the control unit performs control to transmit new capacity restriction information when a temporary restriction on the capacity of the communication device indicated in the capacity restriction information is changed.

7. A communication device as described in claim 1 or 2, wherein the receiving unit receives from the second network a system information block including information for permitting the transmission of information notifying that the capabilities of the communication device are temporarily restricted, the control unit determines that the transmission of information indicating that the capabilities of the communication device are temporarily restricted is permitted based on the information included in the system information block for permitting the transmission of information indicating that the capabilities of the communication device are temporarily restricted, and a transmitting unit transmits the information indicating that the capabilities of the communication device are temporarily restricted to the second network when the transmission of information indicating that the capabilities of the communication device are temporarily restricted is permitted.

8. A base station (210B) of a second network (200B), comprising a transmitter (212T) for transmitting a radio resource control (RRC) reconfiguration message to a communication device (100) that communicates with a first network (200A) and the second network using a plurality of subscriber identity modules, the RRC reconfiguration message being used in the communication device to determine whether or not to transmit capability restriction information relating to a temporarily restricted capability of the communication device.

9. A communication method performed in a communication device (100) that communicates with a first network (200A) and a second network (200B) using multiple subscriber identity modules, comprising: a step of receiving a Radio Resource Control (RRC) reconfiguration message from the second network; and a step of determining whether to transmit capability restriction information related to temporarily restricted capabilities of the communication device based on the RRC reconfiguration message.

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