Communication device, base station, and communication method

Abstract

This communication device (100), which uses a plurality of subscriber identification modules so as to be able to communicate with a plurality of networks (200), comprises a communication unit (120) which receives, from networks (200A, 200B) included in the plurality of networks, a capability inquiry message for requesting capability information pertaining to a communication capability used for communication with the networks. The communication unit transmits, to the networks, the capability information message for transmitting the capability information on the basis of the capability inquiry message. When changing the communication capability used for the communication with the networks, the communication unit transmits, to the networks, a capability change notification which urges the transmission of the capability inquiry message.

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. 2022-126645, filed August 8, 2022, 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 to define a function for a communication device having two transceivers to communicate with multiple networks using multiple subscriber identity modules.

[0004] When such a communication device uses two transceivers for communication with a certain network (hereinafter referred to as the first network), if one of the transceivers is arbitrarily switched to communicate with another network (hereinafter referred to as the second network), the first network may communicate with the communication device without knowing that one of the transceivers has been switched, which may result in data loss between the communication device and the first network.

[0005] Therefore, in 3GPP Release 18, consideration is being given to temporarily limiting the communication capabilities of a communication device used to communicate with a first network so that one of the transceivers can be used to communicate with a second network (see non-patent document 1).

[0006] 3GPP contribution “RP-220955”

[0007] A communication device according to a first aspect is a communication device capable of communicating with a plurality of networks using a plurality of subscriber identity modules. The communication device includes a communication unit that receives a capability inquiry message from a network to request capability information regarding communication capabilities to be used for communication with a network included in the plurality of networks. The communication unit transmits a capability information message to the network to transfer the capability information based on the capability inquiry message. When changing the communication capabilities to be used for communication with the network, the communication unit transmits a capability change notification to the network to prompt the network to send the capability inquiry message.

[0008] A base station according to a second aspect is a base station in a network of a mobile communication system having communication devices capable of communicating with a plurality of networks using a plurality of subscriber identity modules, the base station including a communication unit that receives from the communication device a capability change notification prompting transmission of a capability inquiry message for requesting capability information related to communication capabilities used in communication with the network, transmits the capability inquiry message to the communication device, and receives from the communication device a capability information message for transferring the capability information.

[0009] A communication method according to a third aspect is a communication method executed by a communication device capable of communicating with a plurality of networks using a plurality of subscriber identity modules, comprising the steps of receiving a capability inquiry message from a network included in the plurality of networks to request capability information regarding communication capabilities to be used for communication with the network, transmitting a capability information message to the network based on the capability inquiry message to transfer the capability information, and, when the communication capabilities to be used for communication with the network are to be changed, transmitting a capability change notification to the network to prompt the transmission of the capability inquiry message.

[0010] Objects, features, advantages, etc. of the present disclosure will become clearer from the following detailed description taken in conjunction with 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 an embodiment. FIG. 3 is a diagram (part 1) for describing an assumed scenario. FIG. 4 is a diagram (part 2) for describing an assumed scenario. FIG. 5 is a diagram illustrating an example configuration of a UE (user equipment) according to an embodiment. FIG. 6 is a diagram illustrating an example configuration of a base station according to an embodiment. FIG. 7 is a sequence diagram (part 1) illustrating a first operation example according to an embodiment. FIG. 8 is a sequence diagram (part 2) illustrating the first operation example according to an embodiment. FIG. 9 is a diagram (part 1) for describing information elements in the first operation example according to an embodiment. FIG. 10 is a diagram (part 2) for describing information elements in the first operation example according to an embodiment. FIG. 11 is a sequence diagram illustrating a second operation example according to an 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, currently, existing 3GPP technical specifications do not provide a specific mechanism for temporarily restricting the communication capabilities of a communication device that communicates with a first network when the communication device communicates with a first network and desires to communicate with a second network. Furthermore, existing 3GPP technical specifications do not provide a specific mechanism for temporarily restricting the communication capabilities of a communication device that communicates with a second network while communicating with the first network. As such, there is a concern that the network may not recognize that the communication device desires to temporarily restrict its communication capabilities, leading to inappropriate synchronization between the communication device and the network regarding the temporary restriction of communication capabilities.

[0013] Therefore, one of the objects of the present disclosure is to provide a communication device, a base station, and a communication method that enable a network that communicates with a communication device that can communicate with multiple networks using multiple subscriber identity modules to recognize temporary limitations in the communication capabilities of the communication device.

[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) 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. For example, the UE 100 may be a mobile phone terminal (including a smartphone), a tablet terminal, a notebook PC, a communication module (including a communication card or a 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 is sometimes called a USIM (Universal Subscriber Identity Module).

[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. 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 indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource for performing wireless communication with the UE 100. One cell belongs to one carrier frequency. FIG. 1 shows an example in which the base station 210A manages the cell C1 and the base station 210B manages the 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) With reference to Fig. 2, a configuration example of a protocol stack of the mobile communication system 1 will be described. 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] The UE 100 has an application layer and the like in addition to the radio interface protocol.

[0035] 3 and 4, an assumed scenario in the mobile communication system 1 according to the embodiment will be described. In Release 18 of 3GPP, which is a standardization project for the mobile communication system 1, a work item has been launched to define a function in which the UE 100 having two transceivers communicates with multiple networks using multiple SIMs.

[0036] For example, as shown in Fig. 3A , when UE 100 communicates with first network 200A using SIM 111, UE 100 can use first transceiver unit 121 and second transceiver unit 122 for communication with first network 200A. As shown in Fig. 3B , when UE 100 communicates with second network 200B using SIM 112, it is assumed that UE 100 switches second transceiver unit 122 for communication with second network 200B. This allows UE 100 to communicate with second network 200B using second transceiver unit 122 while maintaining communication with first network 200A using first transceiver unit 121.

[0037] Here, when UE100 uses two transceivers for communication with the first network 200A, if it arbitrarily switches one of the transceivers (e.g., the second transceiver 122) for communication with the second network 200B, data loss may occur between UE100 and the first network 200A because the first network 200A communicates with UE100 without knowing that the second transceiver 122 has been switched.

[0038] Therefore, in 3GPP Release 18, it is being considered to temporarily limit the communication capabilities of UE 100 used for communication with the first network 200A so that one of the transceivers can be used for communication with the second network 200B.

[0039] However, currently, in the existing 3GPP technical specifications, when a UE 100 communicating with a first network 200A wishes to communicate with a second network 200B, there is no specific mechanism for temporarily restricting the communication capabilities of the UE 100 used to communicate with the first network 200A, which raises concerns that problems may arise.

[0040] For example, there is a concern that the first network 200A may not be able to recognize that the UE 100 desires to temporarily restrict the communication capability, and that appropriate synchronization regarding the temporary restriction of the communication capability may not be achieved between the UE 100 and the first network 200A. In one embodiment described later, an operation will be described that enables a network that communicates with the UE 100 that can communicate with a plurality of networks using a plurality of SIMs to recognize the temporary restriction of the communication capability of the UE 100.

[0041] Furthermore, in the existing 3GPP technical specifications, when the UE 100 communicates with the second network 200B while communicating with the first network 200A, there is no specific mechanism for temporarily restricting the communication capability used for communication with the second network 200B. As such, there is a concern that the network cannot recognize that the UE 100 desires to temporarily restrict its communication capability, and that appropriate synchronization regarding the temporary restriction of the communication capability cannot be achieved between the UE 100 and the network. In one embodiment described below, an operation will be described that enables a network communicating with a UE 100 that can communicate with multiple networks using multiple SIMs to recognize the temporary restriction of the communication capability of the UE 100.

[0042] Furthermore, as shown in Figures 4A and 4B, it is assumed that when UE 100 uses the first transceiver unit 121 for communication with the first network 200A and the second transceiver unit 122 for communication with the second network 200B, when UE 100 ends communication with the first network 200A, it switches the first transceiver unit 121 to communication with the second network 200B.

[0043] However, currently, in the existing 3GPP technical specifications, there is no specific mechanism for a UE 100 that has temporarily restricted communication capabilities used for communication with a first network 200A and a second network 200B to release or change the restriction on the communication capabilities of the UE 100 between the UE 100 and the second network 200B, for example, after the UE 100 ends communication with the first network 200A. For this reason, there is a concern that the second network 200B cannot recognize that the UE 100 wishes to release or change the temporary restriction on the communication capabilities, and that appropriate synchronization regarding the temporary restriction on the communication capabilities cannot be achieved between the UE 100 and the second network 200B. In one embodiment described below, an operation will be described that enables a network that communicates with a UE 100 that can communicate with multiple networks using multiple SIMs to recognize the temporary restriction on the communication capabilities of the UE 100.

[0044] In the existing 3GPP technical specifications, there is no specific mechanism for temporarily limiting the communication capability of the UE 100 used for communication with a network, and therefore there is a concern that the UE 100 may not be able to appropriately limit the communication capability. In one embodiment described later, an operation for enabling the UE 100, which can communicate with a plurality of networks using a plurality of SIMs, to appropriately limit the communication capability will be described.

[0045] (Example of UE configuration) An example of the configuration of UE 100 will be described with reference to Fig. 4. As shown in Fig. 4, 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The control unit 130 includes an RRC processing unit 131 and a NAS processing unit 132. The RRC processing unit 131 performs processing in the RRC layer. The NAS processing unit 132 performs processing in the NAS layer, which is a layer higher than the RRC layer. The RRC processing unit 131 and the NAS processing unit 132 may be configured by a single processor or by multiple processors.

[0051] The UE 100 configured in this manner is capable of communicating with multiple networks using multiple SIMs. The communication unit 120 receives a capability query message from the network to request capability information related to communication capabilities used for communication with a network included in the multiple networks. The communication unit 120 transmits a capability information message to the network to transfer the capability information based on the capability query message. When changing the communication capabilities used for communication with a network included in the multiple networks, the communication unit 120 transmits a capability change notification to the network to prompt the transmission of the capability query message. Furthermore, the wireless communication unit 212 of the base station 210 receives the capability change notification from the UE 100 to prompt the transmission of the capability query message, transmits the capability query message to the UE 100, and receives the capability information message from the UE 100.

[0052] This prompts the transmission of the capability inquiry message, and therefore, in response to the network's transmission of the capability inquiry message, the UE 100 can transmit a capability information message to the network. As a result, the network can recognize the temporary restriction on the communication capability of the UE 100 based on the capability information message. Therefore, it is possible to facilitate appropriate synchronization between the UE 100 and the first network 200A regarding the temporary restriction on the communication capability. In addition, by using the "UE capability inquiry message" already described in the specifications as the capability inquiry message and the "UE capability information message" already described in the specifications as the capability information message, it is possible to reduce the impact on the specifications. Note that, in this embodiment, "restricting" may include "reducing." That is, "restricting communication capability" may correspond to reducing communication capability. That is, in this embodiment, "restricting" may be replaced with "reducing."

[0053] In addition, the operation of the functional units of UE100 (specifically, at least one of antenna 101, antenna 102, SIM 111, SIM 112, communication unit 120, and control unit 130 (e.g., RRC processing unit 131 and NAS processing unit 132)) may be described as the operation of UE100.

[0054] (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. 5. 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] In the base station 210 configured in this manner, the wireless communication unit 212 receives a capability change notification from the UE 100 prompting the transmission of a capability query message, transmits the capability query message to the UE 100, and receives a capability information message from the UE 100. This prompts the transmission of the capability query message, so that the UE 100 can transmit a capability information message to the network in response to the network's transmission of the capability query message. As a result, the network can recognize temporary restrictions on the communication capability of the UE 100 based on the capability information message. This makes it easier to appropriately synchronize the UE 100 and the first network 200A regarding temporary restrictions on communication capability. In addition, by using the "UE capability query message" already specified in the specifications as the capability query message and the "UE capability information message" already specified in the specifications as the capability information message, it is possible to reduce the impact on the specifications.

[0059] The operation of the functional units (specifically, at least one of the antenna 211, the wireless communication unit 212, the network communication unit 213, and the control unit 214) of the base station 210A may be described as the operation of the base station 210A.

[0060] (Operation of Mobile Communication System) (1) First Operation Example A first operation example of the mobile communication system 1 will be described with reference to FIGS. 7 to 10 . In this operation example, the UE 100 is present in the primary cell (P cell) 210P and the secondary cell (S cell) 210S of the first network 200A. One base station 210A of the first network 200A may manage the P cell 210P and the S cell 210S. Alternatively, one base station 210A of the first network 200A may manage the P cell 210P, and another base station 210A of the first network 200A may manage the S cell 210S. Note that the P cell 210P may be a P cell in carrier aggregation operation. Also, the S cell 210S may be an S cell in carrier aggregation operation. Also, the P cell 210P may be a P cell belonging to a master cell group (MCG) in dual connectivity operation. The S cell 210S may also be a primary secondary cell (PS cell) belonging to a secondary cell group (SCG) in dual connectivity operation. The S cell 210S may also be a secondary cell (S cell) belonging to a master cell group (MCG) and / or a secondary cell group (SCG) in dual connectivity operation.

[0061] Here, in dual connectivity operation, a P cell of a master cell group (MCG) and / or a primary secondary cell (PS cell) belonging to a secondary cell group (SCG) is also referred to as a special cell (SP cell). Also, in dual connectivity operation, a MAC entity may be associated with each of the master cell group (MCG) and the secondary cell group (SCG).

[0062] Hereinafter, for ease of explanation, in this embodiment, a P cell belonging to a master cell group (MCG) will also be referred to as a P cell. Also, a primary secondary cell (PS cell) belonging to a secondary cell group (SCG) will also be referred to as a secondary cell. That is, in this embodiment, a P cell may be replaced with a P cell belonging to the master cell group (MCG). Also, in this embodiment, a secondary cell may be replaced with a primary secondary cell (PS cell) and / or a secondary cell (S cell) belonging to a secondary cell group (SCG).

[0063] 7 , the UE 100 is in an RRC connected state in the first network 200A. In the RRC connected state, the UE 100 has an RRC connection established between the first network 200A and the UE 100. Therefore, the control unit 130 of the UE 100 and the control unit 214 of the base station 210 perform control to establish an RRC connection between the UE 100 and the base station 210.

[0064] Furthermore, the UE 100 is communicating with the first network 200A. The UE 100 is communicating in the first network 200A. For example, the UE 100 is provided with a service such as a voice call from the first network 200A. Note that "in communication" means that the UE 100 is at least in an RRC connected state in the network. Therefore, when the UE 100 is communicating with the first network 200A, the UE 100 is continuously exchanging data with the network, either continuously or discontinuously.

[0065] 7, the UE 100 is in an RRC idle state or an RRC inactive state in the second network 200B. The UE 100 monitors paging from the second network 200B and receives system block information 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 system block information in the second network 200B during a period in which communication with the first network 200A is interrupted.

[0066] Hereinafter, the communication between the UE 100 and the base station 210A may be, for the UE 100, communication between the UE 100 and the cell of the base station 210A (specifically, the P cell 210P, the S cell 210S), that is, communication between the cell in which the UE 100 is located. The same applies to the communication between the UE 100 and the base station 210B. Furthermore, the communication between the UE 100 and a node belonging to the first network 200A (for example, the base station 210A (i.e., the P cell 210P, the S cell 210S), the mobility management device 221A, the gateway device 222A) may be referred to as the communication between the UE 100 and the first network 200A. The same applies to the communication between the UE 100 and a node belonging to the second network 200B.

[0067] Furthermore, in the following, UE 100 communicates with first network 200A (specifically, transmitting and receiving / notifying messages, etc.) via communication unit 120 (receiving unit 120R and / or transmitting unit 120T), but for ease of explanation, the description of communication via communication unit 120 will be omitted as appropriate. Similarly, the description of communication between UE 100 and second network 200B will be omitted as appropriate as communication via communication unit 120. Therefore, the transmission and / or reception of messages, etc. by UE 100 may be the transmission and / or reception of messages, etc. by communication unit 120 (receiving unit 120R and / or transmitting unit 120T) of UE 100.

[0068] Step S101: In the second network 200B, the AMF 221B transmits, to the base station 210B, a paging request requesting transmission of a paging message addressed to the UE 100. The network communication unit 213 of the base station 210B receives the paging request.

[0069] The paging request may include paging cause information indicating the reason for the paging, such as whether the reason for the paging is a voice call.

[0070] Step S102: In response to receiving the paging request, the radio communication unit 212 of the base station 210B transmits a paging message (Paging) addressed to the UE 100. The RRC processing unit 131 (receiving unit 120R) of the UE 100 receives the paging message from the base station 210B. The RRC processing unit 131 receives the paging message from the base station 210B when the UE 100 is in an RRC idle state or an RRC inactive state in the second network 200B during communication with the first network 200A. The UE 100 may receive the paging message via the first transceiver unit 121 or via the second transceiver unit 122.

[0071] The paging message is used to notify one or more UEs 100. The paging message is a message of the RRC layer. The paging message includes, for example, the ID of the UE 100. More specifically, for example, the paging message includes a list of paging records, and one paging record in the list includes the ID of the UE 100. For example, the ID is the 5G-S-TMSI or full I-RNTI (Inactive Radio Network Temporary Identifier) ​​of the UE 100. The paging message may include paging cause information (Paging Cause). For example, the paging cause information may specify that the cause of the paging is a voice service. The paging cause information may be associated with, for example, the ID of the UE 100.

[0072] The RRC processing unit 131 may perform the processing of step S103 when the paging message includes the ID of UE 100 and UE 100 is in an RRC inactive state or an RRC idle state in the second network 200B while communicating with the first network 200A.

[0073] If the paging message includes the ID of UE100 and UE100 is not communicating with the first network 200A, for example, if UE100 is in an RRC idle state or an RRC inactive state for the first network 200A, the RRC processing unit 131 may not perform the processing of step S103 and may instead perform the specified processing when a paging message is received.

[0074] Step S103: The RRC processing unit 131 provides a paging reception notification to the NAS processing unit 132. The NAS processing unit 132 receives the paging reception notification from the RRC processing unit 131. The paging reception notification is for notifying the UE 100 that it has received a paging. The RRC processing unit 131 may use the paging reception notification to indicate to the NAS processing unit 132 that it has received a paging message in the second network 200B.

[0075] The paging reception notification may include paging cause information (Paging Cause). Note that, for example, when the UE 100 is in an RRC inactive state or an idle state, the paging reception notification may include an identifier (UE ID) of the UE 100.

[0076] In response to receiving the paging message, the control unit 130 may determine whether to temporarily restrict the communication capability of the UE 100 used for communication with the first network 200A. The control unit 130 may determine whether to temporarily restrict the communication capability based on, for example, paging cause information. For example, when the paging cause information indicates a voice service, the control unit 130 may determine to temporarily restrict the communication capability. When the paging cause information indicates a service other than a voice service, the control unit 130 may determine not to temporarily restrict the communication capability.

[0077] Furthermore, the control unit 130 may determine whether to temporarily restrict the communication capability based on, for example, an input from a user. For example, the control unit 130 may determine whether to temporarily restrict the communication capability when the user input recommends communication with the second network 200B. The control unit 130 may determine not to temporarily restrict the communication capability when the user input does not recommend communication with the second network 200B or when there is no user input recommending communication with the second network 200B for a predetermined period after receiving a paging.

[0078] The determination may be made in the NAS processing unit 132, or may be made in a layer higher than the NAS processing unit. When the determination is made in the higher layer, the determination result may be provided to the NAS processing unit 132.

[0079] When it is determined that the communication capability of the UE 100 used for communication with the first network 200A is to be temporarily restricted, the NAS processing unit 132 executes the processing of step S104. When the NAS processing unit 132 temporarily restricts the communication capability of the UE 100, the NAS processing unit 132 may regard this as changing the communication capability. Note that when the NAS processing unit 132 releases or changes the temporary restriction on the communication capability of the UE 100, the NAS processing unit 132 may regard this as changing the communication capability. When the NAS processing unit 132 changes the communication capability, the NAS processing unit 132 may execute the processing of step S104.

[0080] On the other hand, when it is determined that the communication capability of the UE 100 used for communication with the first network 200A will not be temporarily restricted, the control unit 130 may make the following determination without executing the process of step S104. For example, when the communication capability will not be temporarily restricted, the control unit 130 may determine, for example, based on paging cause information, whether or not to prioritize communication with the first network 200A over communication with the second network 200B. When communication with the first network 200A is prioritized, the control unit 130 may perform control to transmit a notification to the second network 200B indicating that the UE 100 will not respond to paging from the second network 200B. On the other hand, when communication with the second network 200B is prioritized, the control unit 130 may perform control to transition from the RRC connected state to the RRC idle state or the RRC inactive state in the first network 200A, and then to the RRC connected state in the second network 200B. The control unit 130 may establish an RRC connection with the second network 200B and communicate with the second network 200B.

[0081] Step S104: The NAS processing unit 132 provides a capability restriction instruction to the RRC processing unit 131. The RRC processing unit 131 receives the capability restriction instruction from the NAS processing unit 132. The capability restriction instruction may be an instruction to transmit a capability change notification, which will be described later.

[0082] Step S105: The RRC processing unit 131 controls transmission of a capability change notification to the first network 200A. The communication unit 120 transmits the capability change notification to the first network 200A. Specifically, the communication unit 120 transmits the capability change notification to the P cell 210P. The communication unit 120 may transmit a message including the capability change notification to the P cell 210P. The radio communication unit 212 of the base station 210A receives the capability change notification from the UE 100 in the P cell 210P.

[0083] The capability change notification prompts transmission of a capability inquiry message. The capability change notification may be, for example, information requesting transmission of a capability inquiry message. The capability change notification may be, for example, information indicating a change in the communication capability of the UE 100. The capability change notification may be, for example, information indicating that there is a change in the communication capability of the UE 100 or information indicating that a change in the communication capability of the UE 100 is desired (or recommended (prefer)). The capability change notification may be, for example, information indicating that the communication capability of the UE 100 is temporarily restricted, information indicating that a temporary restriction on the communication capability of the UE 100 is lifted, and / or information indicating that a temporary restriction on the communication capability of the UE 100 is changed. The capability change notification may be, for example, information indicating that the UE radio access capability is changed or updated.

[0084] The capability change notification may be flag information indicating whether or not to prompt (or request) the transmission of a capability query message. As shown in Fig. 9, if the capability change notification (e.g., "musimCapabilityUpdateRequest") includes predetermined information (e.g., "true") that prompts (or requests) the transmission of a capability query message, it may indicate that the transmission of a capability query message is prompted (or requested). If the capability change notification has an empty field or indicates information other than the predetermined information, it may indicate that the capability change notification does not prompt (or request) the transmission of a capability query message.

[0085] As shown at E11 in Figure 9, the capability change notification may be included in a UE Assistance Information message used for indication of UE assistance information to the network.

[0086] Furthermore, the capability change notification may be included in a request message used for a request regarding a radio resource control (RRC) connection. The request message may be, for example, an RRC setup request (RRCSetupRequest) message, an RRC re-establishment request (RRCReestablishmentRequest) message, an RRC resume request (RRCResumeRequest) message, and / or an RRC resume request 1 (RRCResumeRequest1) message. The RRC setup request message is a message for requesting establishment of an RRC connection. The RRC re-establishment request message is a message for requesting re-establishment of an RRC connection. The RRC resume request message and the RRC resume request 1 message are messages for requesting the resumption of a suspended RRC connection or for performing a Radio Access Network (RAN) based Notification Area (RNA) update.

[0087] Also, as shown in Fig. 10, the capability change notification may be included in a completion message used to confirm successful completion of procedures related to a radio resource control (RRC) connection. The completion message may be, for example, an RRC Setup Complete message (see E13), an RRC Reestablishment Complete message (see E14), and / or an RRC Resume Complete message (see E15). The RRC Setup Complete message is a message used to confirm successful completion of establishment of an RRC connection. The RRC Reestablishment Complete message is a message used to confirm successful completion of re-establishment of an RRC connection. The RRC Resume Complete message is a message used to confirm successful completion of resumption of an RRC connection.

[0088] Furthermore, the capability change notification may be included in a UE information response (UEInformationResponse) message for transferring the requested information to the network. Note that the UE 100 transmits the UE information response message based on a UE information request (UEInformationRequest) message from the network. The UE information request message is a message used by the network to retrieve information from the UE 100.

[0089] When the UE 100 is in a state of simultaneous parallel communication with the first network 200A using a plurality of transceivers, the RRC processing unit 131 (control unit 130) may include a capability change notification in a message to be transmitted to the first network 200A. When the UE 100 is in a state of simultaneous parallel communication with the first network 200A using a plurality of transceivers, the communication unit may transmit the capability change notification to the first network 200A.

[0090] The control unit 214 of the base station 210A may execute the process of step S106 based on the reception of the capability change notification. The control unit 214 may determine whether or not to transmit a capability query message. If the control unit 214 determines to transmit a capability query message, it may execute the process of step S106. On the other hand, if the control unit 214 determines not to transmit a capability query message, it may end the following process.

[0091] Step S106: The wireless communication unit 212 of the base station 210A transmits a capability query message (for example, a UE capability query (UECapabilityQuery) message) to the UE 100 in the P cell 210P to request capability information regarding communication capabilities to be used for communication with the first network 200A. The communication unit 120 of the UE 100 receives the capability query message from the P cell 210P (first network 200A). The message may be a response to a capability change notification. The UE capability query message is a message used to request UE radio access capabilities not only for other RATs (Radio Access Technologies) but also for NR (NR Radio Access).

[0092] Step S107: The RRC processing unit 131 controls transmission of a capability information message (e.g., a UE capability information (UECapabilityInformation) message) for transferring capability information to the first network 200A. The communication unit 120 transmits the capability information message to the first network 200A. Specifically, the communication unit 120 transmits the capability information message to the P cell 210P. The wireless communication unit 212 of the base station 210A receives the capability information message from the UE 100 in the P cell 210P. The UE capability information message is a message used to transfer UE access capabilities requested by the network.

[0093] The control unit 130 includes in the capability information message the changed capability information of the communication capability used for communication with the first network 200A. If the changed communication capability is a temporarily restricted communication capability, the capability information may be referred to as restriction information.

[0094] When the control unit 130 has already transmitted a capability information message in the first network 200A, the control unit 130 may include, in the capability information message, information that has been changed from the previously transmitted information as capability information (restriction information). Therefore, the control unit 130 may include, in the capability information message, information indicating the temporarily restricted communication capability as the UE access capability.

[0095] The control unit 214 of the base station 210A may determine, based on the restriction information, whether to temporarily restrict the communication capability of the UE 100 used for communication with the first network 200A. When the control unit 214 of the base station 210A determines to temporarily restrict the communication capability of the UE 100, the control unit 214 may execute the process of step S108. When the control unit 214 of the base station 210A determines not to temporarily restrict the communication capability of the UE 100, the control unit 214 may end the process.

[0096] Step S108: The network communication unit 213 of the base station 210A that manages the P cell 210P may transmit a scheduling stop instruction to another base station 210A that manages the S cell 210S. When the base station 210A manages the P cell 210P and the S cell 210S, the base station 210A may send the scheduling stop instruction from the entity that manages the P cell 210P to the entity that manages the S cell 210S within the control unit 214.

[0097] The scheduling stop instruction may be for stopping the scheduling assigned to the UE 100, or may be for stopping a part of the scheduling assigned to the UE 100. The scheduling stop instruction may include information included in the UE capability information message (for example, information on at least a part of the restriction information).

[0098] Based on the scheduling stop instruction, the control unit 214 of the base station 210A that manages the S cell 210S may temporarily limit the communication capability of the UE 100. The network communication unit 213 of the base station 210A may transmit a response message indicating that scheduling will be stopped to the base station 210A that manages the P cell 210P. Based on the reception of the response message, the control unit 214 of the base station 210A that manages the P cell 210P may execute the process of step S109.

[0099] Step S109: In the P cell 210P, the radio communication unit 212 of the base station 210A transmits a message (for example, an RRC reconfiguration message) including configuration information for temporarily restricting the communication capability of the UE 100 to the UE 100. The communication unit 120 of the UE 100 receives the message including the configuration information from the P cell 210P (first network 200A). The message may be a response to the restriction information.

[0100] The configuration information may include information indicating at least one configuration (e.g., reduced configuration) of a secondary cell (or secondary cell group), a frequency band, and a multiple-input multiple-output (MIMO) layer.

[0101] The control unit 130 (e.g., the RRC processing unit 131) restricts communication capabilities based on the configuration information. The control unit 130 may reduce or release secondary cells or secondary cell groups based on the configuration information. The control unit 130 may reduce frequency bands based on the configuration information. The control unit 130 may reduce the number of MIMO layers based on the configuration information.

[0102] The control unit 130 executes control to continue communication with the first network 200A via some of the multiple transceivers (e.g., the first transceiver 121) using the communication capabilities of the UE 100 that have not been temporarily limited. The control unit 130 may perform communication with the first network 200A via the first transceiver 121 based on an RRC setting based on setting information received from the first network 200A. The control unit 130 may, for example, maintain the RRC setting used for communication with the first network 200A via the first transceiver 121. The control unit 130 may release at least a portion of the RRC setting used for communication with the first network 200A via the second transceiver 122, and start communication with the first network 200A via the first transceiver 121 based on the remaining RRC setting.

[0103] Meanwhile, the control unit 130 executes control to terminate communication with the first network 200A via some of the multiple transceivers (e.g., the second transceiver 122). The control unit 130 may, for example, release the RRC setting used for communication with the first network 200A via the second transceiver 122. The control unit 130 executes control to restrict communication capacity and start connection with the second network 200B.

[0104] Step S110: Based on the execution of the restriction on the communication capacity, the RRC processing unit 131 provides a second NW switching preparation completion notification to the NAS processing unit 132. The NAS processing unit 132 receives the second NW switching preparation completion notification from the RRC processing unit 131. The second NW switching preparation completion notification may be a notification indicating that preparation for establishing an RRC connection with the second network 200B has been completed.

[0105] Step S111: Based on the reception of the second NW switching completion notification, the NAS processing unit 132 provides a second NW connection instruction to the RRC processing unit 131. The RRC processing unit 131 receives the second NW connection instruction from the NAS processing unit 132. The second NW connection instruction may be an instruction to establish an RRC connection with the second network 200B.

[0106] Step S112: The RRC processing unit 131 performs processing for starting an RRC connection with the base station 210B based on the second NW connection instruction. The RRC processing unit 131 may perform, for example, an RRC setup procedure (Setup) for establishing an RRC connection or an RRC re-establishment procedure (Reestablishment) for re-establishing an RRC connection. The RRC processing unit 131 may also perform an RRC resume procedure (Resume) for resuming a suspended RRC connection. In this operation example, a case in which the RRC processing unit 131 performs the RRC re-establishment procedure will be described as an example.

[0107] The RRC processing unit 131 controls transmission of an RRC re-establishment request message to the second network 200B (specifically, the base station 210B). The communication unit 120 transmits the RRC re-establishment request message to the second network 200B. The radio communication unit 212 of the base station 210B receives the RRC re-establishment request message from the UE 100.

[0108] Step S113: The wireless communication unit 212 of the base station 210B transmits an RRC re-establishment message used to re-establish SRB (Signaling Radio Bearer) 1 to the UE 100. The communication unit 120 of the UE 100 receives the RRC re-establishment message from the base station 210B (second network 200B). The control unit 130 of the UE 100 performs processing to re-establish an RRC connection (for example, SRB1) based on the RRC re-establishment message. After performing the processing to re-establish the RRC connection, the control unit 130 performs the processing of step S114.

[0109] Step S114: The RRC processing unit 131 controls transmission of an RRC re-establishment completion message to the second network 200B (specifically, the base station 210B). The communication unit 120 transmits the RRC re-establishment completion message to the second network 200B. The radio communication unit 212 of the base station 210B receives the RRC re-establishment completion message from the UE 100.

[0110] The control unit 130 may include the capability change notification in the RRC re-establishment completion message. When the control unit 130 is communicating with the first network 200A using at least one transceiver unit (e.g., the first transceiver unit 121) of the plurality of transceivers and is communicating with the second network 200B using a transceiver unit (e.g., the second transceiver unit 122) different from the at least one transceiver unit of the plurality of transceivers, the control unit 130 may include the capability change notification in the RRC re-establishment completion message.

[0111] The communication unit 120 may send a capability change notification to the second network 200B when it is communicating with the first network 200A using at least one of the multiple transmission / reception units (e.g., the first transmission / reception unit 121) and communicating with the second network 200B using a transmission / reception unit (e.g., the second transmission / reception unit 122) different from at least one of the multiple transmission / reception units.

[0112] Upon receiving the capability change notification, the control unit 214 of the base station 210B may execute the same processing as that of the base station 210A (see the processing of step S105).

[0113] Note that, based on the reception of the capability change notification, the control unit 214 of the base station 210B may suspend configuring the settings of the UE 100. The control unit 214 of the base station 210B may suspend configuring the settings of the UE 100 until a capability information message is received. The control unit 214 of the base station 210B may suspend configuring the settings of the UE 100 until a predetermined time has elapsed since the reception of the capability change notification.

[0114] Step S115: As in step S106, the wireless communication unit 212 of the base station 210B transmits a capability query message (for example, a UE capability query message) to request capability information related to communication capabilities used for communication of the second network 200B to the UE 100. The communication unit 120 of the UE 100 receives the capability query message from the second network 200B (base station 210B).

[0115] Step S116: As in step S107, the RRC processing unit 131 controls transmission of a capability information message (e.g., a UE capability information message) for transferring capability information to the second network 200B. The communication unit 120 transmits the capability information message to the second network 200B. The radio communication unit 212 of the base station 210B receives the capability information message from the UE 100.

[0116] As in step S107, the control unit 130 includes the changed capability information of the communication capability used for communication with the second network 200B in the capability information message.

[0117] Based on the reception of the capability information message, the control unit 214 of the base station 210B may execute the same process as that of the base station 210A (see the process of step S105). Note that, if the control unit 214 of the base station 210B has suspended the configuration of the settings of the UE 100, the control unit 214 may start (resume) the configuration of the settings of the UE 100.

[0118] Step S117: The radio communication unit 212 of the base station 210B may transmit to the UE 100 a message (for example, an RRC reconfiguration message) including configuration information for temporarily restricting the communication capability of the UE 100. The communication unit 120 of the UE 100 receives the message including the configuration information from the second network 200B (base station 210B). The base station 210B may execute the same process as the base station 210A (see the process of step S109).

[0119] Thereafter, the UE 100 communicates with the second network 200B. For example, the control unit 130 of the UE 100 may start processing for performing communication corresponding to the paging message in the second network 200B. The control unit 130 of the UE 100 may control the communication with the second network 200B via the second transceiver unit 122. Note that the control unit 130 may continue to control the communication with the first network 200A via the first transceiver unit 121.

[0120] As described above, communication unit 120 receives a capability inquiry message from a network to request capability information related to communication capabilities used for communication with a network included in the plurality of networks. Communication unit 120 transmits a capability information message to the network to transfer the capability information based on the capability inquiry message. When communication unit 120 changes the communication capabilities used for communication with a network included in the plurality of networks, it transmits a capability change notification to the network to prompt the network to send a capability inquiry message.

[0121] This prompts the transmission of the capability query message, and therefore, in response to the network's transmission of the capability query message, the UE 100 can transmit a capability information message to the network. As a result, the network can recognize the temporary restriction on the communication capability of the UE 100 based on the capability information message. Therefore, it is possible to facilitate appropriate synchronization between the UE 100 and the first network 200A regarding the temporary restriction on the communication capability. In addition, by using the "UE capability query message" already described in the specifications as the capability query message and the "UE capability information message" already described in the specifications as the capability information message, it is possible to reduce the impact on the specifications.

[0122] Furthermore, the capability change notification may be included in a request message used for a request regarding the RRC connection. This allows the UE 100 to send the capability change notification to the network when making a request regarding the RRC connection, thereby eliminating the need to transmit a new message just for notifying the capability change notification, and enabling effective use of radio resources.

[0123] Furthermore, the capability change notification may be included in a completion message used to confirm that the procedure related to the RRC connection has been successfully completed. This allows the UE 100 to send the capability change notification to the network when notifying that the procedure related to the RRC connection has been successfully completed, thereby eliminating the need to transmit a new message just for notifying the capability change notification and enabling effective use of radio resources.

[0124] Furthermore, the capability change notification may be included in a UE assistance information message used for indicating UE assistance information to the network, thereby enabling the UE 100 to spontaneously transmit the capability change notification to the network.

[0125] Furthermore, the capability change notification may be included in a UE information response message for transferring the requested information to the network. This allows the UE 100 to send the capability change notification to the network when responding to the UE information request message, eliminating the need to transmit a new message just for notifying the capability change notification, thereby enabling effective use of radio resources.

[0126] Furthermore, the control unit 130 may include, in the capability information message, capability information after the change of the communication capability used for communication with the network. This allows the base station 210 to grasp the communication capability after the change. Furthermore, by using the "UE capability information message" already described in the specifications as the capability information message, the impact on the specifications can be reduced.

[0127] Furthermore, the communication unit 120 may transmit the capability change notification to the network when the UE 100 is in a state of simultaneous parallel communication with the network using a plurality of transceivers. For example, when the UE 100 is using some of the plurality of transceivers for communication with the first network 200A, the UE 100 can communicate with the second network 200B using the remaining transceivers, and therefore it is possible to omit transmitting the capability change notification to the first network 200A.

[0128] Furthermore, the communication unit 120 may transmit a capability change notification to a network when it is communicating with a network (e.g., the second network 200B) using at least one of the multiple transceivers, and is also communicating with another network (e.g., the first network 200A) using a transceiver different from the at least one of the multiple transceivers, thereby enabling the base station 210 of the second network 200B to recognize that its communication capability has been temporarily restricted.

[0129] (2) Second Operation Example The second operation example will be described, mainly focusing on differences from the above-described operation example, with reference to Fig. 11. In the second operation example, a case will be described in which the UE 100 transmits, to the second network 200B, information for releasing or changing a temporary restriction on the communication capability for communication with the second network.

[0130] In the second operation example, the UE 100 is in an RRC connected state in the first network 200A. The UE 100 communicates with the first network 200A. Specifically, the UE 100 communicates with the P cell 210P (or MCG). On the other hand, the UE 100 does not communicate with the S cell 210S (or SCG).

[0131] Furthermore, the UE 100 is in an RRC connected state in the second network 200B. The UE 100 is communicating with the second network 200B. Specifically, the UE 100 is communicating with the P cell 210P (or MCG). On the other hand, the UE 100 is not communicating with the S cell 210S (or SCG). The UE 100 may use the first transceiver 121 for communication with the first network 200A and the second transceiver 122 for communication with the second network 200B.

[0132] As in the first operation example, the control unit 130 of the UE 100 temporarily restricts the communication capability of the UE 100 used for communication with the first network 200A, in order to communicate with the second network 200B. Also, in order to communicate with the first network 200A, the control unit 130 temporarily restricts the communication capability of the UE 100 used for communication with the second network 200B.

[0133] Step S201: The UE 100 terminates communication with the first network 200A.

[0134] Step S202: The radio communication unit 212 of the base station 210A transmits an RRC release message to the UE 100. The communication unit 120 of the UE 100 receives the RRC release message from the base station 210A. Based on the reception of the RRC release message, the control unit 130 of the UE 100 transitions from the RRC connected state to the RRC idle state or the RRC inactive state in the first network 200A. As a result, the UE 100 may release the RRC connection in the first network 200A.

[0135] Step S203: The control unit 130 (e.g., the RRC processing unit 131) may provide a release completion notification indicating the completion of release of the RRC connection to the NAS processing unit 132. In response to receiving the release completion notification, the control unit 130 (e.g., the NAS processing unit 132 or a processing unit in a layer higher than the NAS layer) may determine whether to release the temporary restriction on the communication capability of the UE 100 used for communication with the second network 200B. Furthermore, the control unit 130 may determine whether to change the temporary restriction on the communication capability.

[0136] The control unit 130 may determine to release or change the temporary restriction based on, for example, a transition to an RRC idle state in the first network 200A. The control unit 130 may determine not to release or change the temporary restriction based on, for example, a transition to an RRC inactive state in the first network 200A.

[0137] The control unit 130 may determine whether to lift the temporary restriction or whether to change the temporary restriction based on the service provided from the second network 200B. The control unit 130 may determine to lift the temporary restriction when the service provided from the second network 200B is a voice service. The control unit 130 may determine not to lift the temporary restriction when the service provided from the second network 200B is a service other than a voice service. In this case, the control unit 130 may determine to change the temporary restriction.

[0138] The control unit 130 may determine whether to lift the temporary restriction or whether to change the temporary restriction based on, for example, an input from the user. The control unit 130 may determine to lift the temporary restriction when the user's input prioritizes communication with the second network 200B over communication with the first network 200A. The control unit 130 may determine not to lift the temporary restriction when the user's input does not prioritize communication with the second network 200B over communication with the first network 200A.

[0139] The determination may be made in the NAS processing unit 132, or may be made in a layer higher than the NAS processing unit. When the determination is made in the higher layer, the determination result may be provided to the NAS processing unit 132.

[0140] If it is determined that the temporary restriction on the communication capability of the UE 100 used for communication with the second network 200B is to be lifted or changed, the NAS processing unit 132 executes the process of step S204. On the other hand, if it is determined that the temporary restriction on the communication capability of the UE 100 used for communication with the second network 200B is not to be lifted or changed, the control unit 130 may end the process of this operation without executing the process of step S204.

[0141] Step S204: As shown in Fig. 11 , when it is determined to release the temporary restriction on the communication capability of the UE 100 used for communication with the second network 200B, the NAS processing unit 132 provides a capability restriction release instruction to the RRC processing unit 131. The RRC processing unit 131 receives the capability restriction release instruction from the NAS processing unit 132. The capability restriction release instruction may be for issuing an instruction to transmit restriction release information, which will be described later. The capability restriction release instruction may indicate the content of the restriction release information.

[0142] When it is determined that the temporary restriction on the communication capability of the UE 100 used for communication with the second network 200B is to be changed, the NAS processing unit 132 provides a capacity restriction change instruction to the RRC processing unit 131. The RRC processing unit 131 receives the capacity restriction change instruction from the NAS processing unit 132. The capacity restriction change instruction may be for instructing transmission of restriction change information, which will be described later. The capacity restriction change instruction may indicate the content of the restriction change information.

[0143] Step S205: The control unit 130 (RRC processing unit 131) performs control to transmit a capability change notification to the second network 200B based on the capability restriction release instruction. The communication unit 120 transmits the capability change notification to the second network 200B. Specifically, the communication unit 120 transmits the capability change notification to the P cell 210P. The communication unit 120 may transmit a message including the capability change notification to the P cell 210P. The wireless communication unit 212 of the base station 210B receives the capability change notification from the UE 100 in the P cell 210P.

[0144] When the RRC processing unit 131 (control unit 130) is communicating with the second network 200B using at least one transceiver unit among the multiple transceivers and has terminated communication with the first network 200A using a transceiver unit different from at least one of the multiple transceivers, the RRC processing unit 131 (control unit 130) may include a capability change notification in a message to be transmitted to the second network 200B. When the communication unit 120 is communicating with the second network 200B using at least one transceiver unit among the multiple transceivers and has terminated communication with the first network 200A using a transceiver unit different from at least one of the multiple transceivers, the communication unit 120 may transmit the capability change notification to the second network 200B.

[0145] The control unit 214 of the base station 210B may execute the process of step S206 based on the reception of the capability change notification. The base station 210B may execute the same process as the base station 210A.

[0146] Step S206: corresponds to step S115.

[0147] Step S207: The control unit 130 (RRC processing unit 131) controls transmission of a capability information message (e.g., a UE capability information message) for transferring capability information to the second network 200B. The communication unit 120 transmits the capability information message to the second network 200B. The wireless communication unit 212 of the base station 210B receives the capability information message from the UE 100.

[0148] As in step S107, the control unit 130 includes in the capability information message the capability information after the change (sometimes referred to as restriction release information) of the communication capability used for communication with the second network 200B. The control unit 130 may include the restriction release information in the capability information message as the capability information after the change. The restriction release information is used to release a temporary restriction on the communication capability of the UE 100 used for communication with the second network 200B. The restriction release information may be information indicating the normal communication capability of the UE 100 (unrestricted communication capability).

[0149] Step S208: The network communication unit 213 of the base station 210B that manages the P cell 210P may transmit a scheduling start instruction to another base station 210B that manages the S cell 210S. When the base station 210B manages the P cell 210P and the S cell 210S, the base station 210B may send the scheduling start instruction from the entity that manages the P cell 210P to the entity that manages the S cell 210S within the control unit 214.

[0150] The scheduling start instruction may be for starting scheduling assigned to the UE 100, or may be for starting part of scheduling assigned to the UE 100. The scheduling start instruction may include at least part of the information of the restriction change information.

[0151] Based on the scheduling start instruction, the control unit 214 of the base station 210B that manages the S cell 210S may release the temporary restriction on the communication capability of the UE 100. The network communication unit 213 of the base station 210B may transmit a response message indicating that scheduling start will be executed to the base station 210B that manages the P cell 210P. Based on the reception of the response message, the control unit 214 of the base station 210B that manages the P cell 210P may execute the process of step S209.

[0152] Step S209: In the P cell 210P, the radio communication unit 212 of the base station 210B transmits to the UE 100 a message (for example, an RRC reconfiguration message) including configuration information for releasing or changing the temporary restriction on the communication capability of the UE 100. The communication unit 120 of the UE 100 receives the message including the configuration information from the P cell 210P (second network 200B).

[0153] The setting information may include information indicating at least one setting of a secondary cell (or a secondary cell group), a frequency band, and a MIMO layer. The setting information may include information for setting a MUSIM gap. The information may indicate a MUSIM gap setting recommended by the UE 100, or may indicate a different MUSIM gap setting.

[0154] Step S210: The UE 100 starts communication with the S cell 210S (or SCG) while maintaining communication with the P cell 210P (or MCG).

[0155] The control unit 130 (e.g., the RRC processing unit 131) removes or changes the restriction on communication capability based on the setting information. The control unit 130 may set a secondary cell or a secondary cell group based on the setting information. The control unit 130 may set a frequency band based on the setting information. The control unit 130 may set the number of MIMO layers based on the setting information.

[0156] Based on the RRC setting based on the setting information received from the second network 200B, the control unit 130 may communicate with the second network 200B via the first transceiver unit 121, in addition to communicating with the second network 200B via the second transceiver unit 122. The control unit 130 may, for example, communicate with the P cell 210P (or MSG) via the second transceiver unit 122, and may also communicate with the S cell 210S (or SCG) via the first transceiver unit 121.

[0157] The setting information may include information for setting a MUSIM gap. As an example of a MUSIM operation, the controller 130 may monitor paging in the first network 200A or attempt to receive a system information block during the set MUSIM gap.

[0158] As described above, when the communication unit 120 is communicating with the second network 200B using at least one of the plurality of transceivers, and has terminated communication with the first network 200A using a transceiver different from the at least one of the plurality of transceivers, the communication unit 120 may transmit a capability change notification to the second network 200B. This allows the UE 100 to use the transceiver that was used for communication with the first network 200A for communication with the second network 200B.

[0159] [Other Embodiments] In the above-described embodiment, the case where the UE 100 has two transceivers is described, but this is not limited thereto. The UE 100 may have a plurality of transceivers. For example, the UE 100 may have three or more transceivers.

[0160] In the above-described embodiment, the UE 100 starts the procedure for transmitting the restriction information in response to paging from the first network 200A, but this is not limiting. The UE 100 may start the procedure in response to, for example, an input from a user.

[0161] 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.

[0162] 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 (Long Term Evolution) or another generation system (e.g., 6th generation) of the 3GPP standard. The base station 210 may be an eNB that provides E-UTRA user plane and control plane protocol termination toward 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.

[0163] 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)).

[0164] 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.

[0165] 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.

[0166] (Additional Notes) Additional notes will be given regarding the features of the above-described embodiment.

[0167] (Supplementary Note 1) A communication device capable of communicating with a plurality of networks using a plurality of subscriber identity modules, comprising: a communication unit that receives a capability inquiry message from a network to request capability information regarding communication capabilities to be used for communication with a network included in the plurality of networks; the communication unit transmits a capability information message to the network to transfer the capability information based on the capability inquiry message; and when changing the communication capabilities to be used for communication with the network, the communication unit transmits a capability change notification to the network to prompt the network to send the capability inquiry message.

[0168] (Supplementary Note 2) The communications device according to Supplementary Note 1, wherein the capability change notification is included in a request message used for a request regarding a Radio Resource Control (RRC) connection.

[0169] The request message may be, for example, an RRC setup request (RRCSetupRequest) message, an RRC re-establishment request (RRCReestablishmentRequest) message, an RRC resume request (RRCResumeRequest) message, and / or an RRC resume request 1 (RRCResumeRequest1) message.

[0170] (Supplementary Note 3) The communication device according to Supplementary Note 1 or 2, wherein the capability change notification is included in a completion message used to confirm successful completion of a procedure related to a radio resource control (RRC) connection.

[0171] The completion message may be, for example, an RRC setup complete (RRCSetupComplete) message (see E13), an RRC re-establishment complete (RRCReestablishmentComplete) message, and / or an RRC resume complete (RRCResumeComplete) message.

[0172] (Supplementary Note 4) The communication device according to any one of Supplementary Notes 1 to 3, wherein the capability change notification is included in a UE assistance information message used for indicating UE assistance information to the network.

[0173] (Supplementary Note 5) The communications device according to any one of Supplementary Notes 1 to 4, wherein the capability change notification is included in a UE information response message for transferring the requested information to the network.

[0174] (Supplementary Note 6) The communication device according to any one of Supplementary Notes 1 to 5, further comprising: a control unit that includes, in the capability information message, capability information after a change in communication capability used for communication with the network.

[0175] (Supplementary Note 7) The communication device according to any one of Supplementary Notes 1 to 6, wherein the communication unit has a plurality of transceivers, and the communication unit transmits the capability change notification to the network when the communication device is in a state of simultaneous parallel communication with the network using the plurality of transceivers.

[0176] (Supplementary Note 8) The communication device according to any one of Supplementary Notes 1 to 7, wherein the communication unit has a plurality of transceivers, and the communication unit transmits the capability change notification to the network when communicating with the network using at least one of the plurality of transceivers and communicating with another network using a transceiver different from the at least one of the plurality of transceivers.

[0177] (Supplementary Note 9) The communication device according to any one of Supplementary Notes 1 to 8, wherein the communication unit has a plurality of transceivers, and the communication unit communicates with the network using at least one of the plurality of transceivers, and transmits the capability change notification to the network when the communication unit has terminated communication with another network using a transceiver different from the at least one of the plurality of transceivers.

[0178] (Supplementary Note 10) A base station in a network of a mobile communication system having communication devices capable of communicating with a plurality of networks using a plurality of subscriber identity modules, comprising a communication unit, the communication unit: receives from the communication device a capability change notification prompting the transmission of a capability inquiry message for requesting capability information regarding communication capabilities to be used for communication with the network; transmits the capability inquiry message to the communication device; and receives from the communication device a capability information message for transferring the capability information.

[0179] (Supplementary Note 11) A communication method executed by a communication device capable of communicating with a plurality of networks using a plurality of subscriber identity modules, comprising the steps of: receiving a capability inquiry message from a network to request capability information regarding communication capabilities to be used for communication with a network included in the plurality of networks; transmitting a capability information message to the network to transfer the capability information based on the capability inquiry message; and, when changing the communication capabilities to be used for communication with the network, transmitting a capability change notification to the network to prompt the transmission of the capability inquiry message.

Claims

1. A communication device (100) capable of communicating with a plurality of networks (200) using a plurality of subscriber identity modules, a control unit that temporarily limits a capability of the communication device used for communication with a first network in order to communicate with a second network; and a communication unit configured to transmit information to the second network indicating that the capability is temporarily restricted. Communications equipment.

2. The information is included in a completion message used to confirm successful completion of a procedure related to a Radio Resource Control (RRC) connection. The communication device according to claim 1 .

3. The completion message is an RRC setup completion message or an RRC resume completion message. The communication device according to claim 2 .

4. The communication unit transmits restriction information for temporarily restricting the capability to the second network.

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

5. The communication unit receives a radio resource control (RRC) reconfiguration message including configuration information for temporarily restricting the capability.

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

6. A base station (210B) of a network (200B) in a mobile communication system having a communication device (100) capable of communicating with a plurality of networks (200) using a plurality of subscriber identity modules, A communication unit (212) that receives information indicating that the capability is temporarily restricted from the communication device that temporarily restricts the capability used for communication with another network (200A) Base station.

7. A communication method performed in a communication device (100) capable of communicating with a plurality of networks (200) using a plurality of subscriber identity modules, comprising: temporarily restricting the ability of the communication device to communicate with a first network in order to communicate with a second network; and transmitting information to the second network indicating that the capabilities are temporarily restricted. Communication methods.