JP7160114B2 - Terminal device, wireless communication device, wireless communication system and wireless communication method - Google Patents

Description

The present invention relates to a terminal device, a radio communication device, a radio communication system, and a radio communication method.

In LTE (Long Term Evolution), signal integrity assurance and encryption are performed between a terminal device (User Equipment: UE) and a base station (evolved Node-B: eNB). In wireless communication between the terminal device and the eNB, the keys used for integrity assurance and encryption of the C (Control)-Plane signal and the U (User)-Plane signal are managed by the UE and the eNB respectively. .

Here, the security algorithm for signal integrity assurance and ciphering uses an algorithm that can be used by both the UE and the eNB. In the following, security algorithms may be simply referred to as algorithms. Algorithms used in LTE include SNOW 3G, ASE (Advanced Encryption Standard), ZUC, and the like.

Security-related processing between UE and eNB in LET is performed as follows. When connecting for the first time, the UE transmits an algorithm that can be used by the own device to the MME (Mobility Management Entity) as UE Security Capability. The MME sends the obtained UE Security Capability to the eNB.

When switching the base station to be connected by X2 handover, security-related processing is executed as follows. Here, a case where there are two eNBs, a first eNB and a second eNB, will be described. When the UE connected to the first eNB moves within the serving area and connects to the second eNB, the UE transmits one or more available algorithms to the second eNB as UE Security Capabilities. The second eNB that has received the UE Security Capability selects an algorithm and establishes radio connection with the UE. At this time, if the second eNB does not support an algorithm that the UE can use, the second eNB fails to establish a connection with the UE.

In addition, in the 5th generation mobile communication system called 5G (Generation), a wider variety of services than LET are provided, utilizing ultra-reliable and low-delay communication such as URLLC (Ultra-Reliable and Low Latency Communications). It is assumed that In addition, in order to realize services with higher security, it is assumed that the algorithms used for signal integrity assurance and encryption also differ for each service. Furthermore, new algorithms may be added due to the diversification of services. For example, it is assumed that each gNB is used for a specific service and that different algorithms are available for each gNB.

In 5G, there is a state called RRC_inactive as a state of RRC (Radio Resource Control). This is a state in which the wireless channel between the base station and the terminal device is disconnected while the AS context including AS (Access Stratum) information such as security and the upper line are maintained. is equivalent to conventional RRC_idle. However, unlike the case where the base station maintains the AS context and shifts from RRC_idel (waiting state) to RRC_connection (connection state), the terminal device in this case is RRC-inactive ( wireless line disconnected and upper line connected state) to RRC_connection. That is, by using RRC_inactive, it is possible to reduce the number of procedures and signals, and shorten the time until transmission of user data is started. Furthermore, low power consumption is also possible. Note that, in RRC_inactive, location registration is performed in a RAN (Radio Access Network) area that is narrower than a conventional tracking area (TA: Tracking Area). Note that the tracking area and the RAN area are sometimes called a location registration area.

Here, there are two update procedures for updating the location registration area: TAU (Tracking Area Update) and RAU (RAN Area Update). The TAU is a process in which a terminal periodically (regularly) reports the area within which the terminal device is located to the network in order to let the base station know the area within which the terminal is located when a call is received. Also, in the RRC_inactive state, the RAU performs processing for the terminal device to perform location registration periodically in a RAN area narrower than the TA. As described above, the terminal device uses RA when transitioning from RRC-inactive to RRC_connection.

As a technology related to wireless communication security, the source base station determines whether or not communication with the destination base station is possible based on security capability information received from the terminal device. There is a conventional technique for transmitting information of a security key to be used for a terminal device. There is also a conventional technique in which a terminal receives a list of compatible security algorithms delivered from a network when handing over to another network and selects a security algorithm.

WO2018/079692 Japanese Patent Publication No. 2012-531792

3GPP TS 23.501 V15.3.0 (2018-09) 3GPP TS 36.211 V15.2.0 (2018-06) 3GPP TS 36.212 V15.2.1 (2018-07) 3GPP TS 36.213 V15.2.0 (2018-06) 3GPP TS 36.300 V15.2.0 (2018-06) 3GPP TS 36.321 V15.2.0 (2018-07) 3GPP TS 36.322 V15.1.0 (2018-07) 3GPP TS 36.323 V15.0.0 (2018-07) 3GPP TS 36.331 V15.2.2 (2018-06) 3GPP TS 36.413 V15.2.0 (2018-06) 3GPP TS 36.423 V15.2.0 (2018-06) 3GPP TS 36.425 V15.0.0 (2018-06) 3GPP TS 37.340 V15.2.0 (2018-06) 3GPP TS 38.201 V15.0.0 (2017-12) 3GPP TS 38.202 V15.2.0 (2018-06) 3GPP TS 38.211 V15.2.0 (2018-06) 3GPP TS 38.212 V15.2.0 (2018-06) 3GPP TS 38.213 V15.2.0 (2018-06) 3GPP TS 38.214 V15.2.0 (2018-06) 3GPP TS 38.215 V15.2.0 (2018-06) 3GPP TS 38.300 V15.2.0 (2018-06) 3GPP TS 38.321 V15.2.0 (2018-06) 3GPP TS 38.322 V15.2.0 (2018-06) 3GPP TS 38.323 V15.2.0 (2018-06) 3GPP TS 38.331 V15.2.1 (2018-06) 3GPP TS 38.401 V15.2.0 (2018-06) 3GPP TS 38.410 V15.0.0 (2018-06) 3GPP TS 38.413 V15.0.0 (2018-06) 3GPP TS 38.420 V15.0.0 (2018-06) 3GPP TS 38.423 V15.0.0 (2018-06) 3GPP TS 38.470 V15.2.0 (2018-06) 3GPP TS 38.473 V15.2.1 (2018-07) 3GPP TR 38.801 V14.0.0 (2017-03) 3GPP TR 38.802 V14.2.0 (2017-09) 3GPP TR 38.803 V14.2.0 (2017-09) 3GPP TR 38.804 V14.0.0 (2017-03) 3GPP TR 38.900 V15.0.0 (2018-06) 3GPP TR 38.912 V15.0.0 (2018-06) 3GPP TR 38.913 V15.0.0 (2018-06)

However, when a terminal (UE) connected to a certain base station (gNB) is in the RRC_inactive state and then moves in the area (moves between areas), the gNB connected at the destination and before the movement It is conceivable that the algorithms that can be used by the gNB that was connected to are different. In this case, the transition from the state of RRC_inactive to RRC_connected may fail. If the transition to RRC_connected fails, the terminal device becomes RLF (Radio Link Failure). In this case, a communication interruption for the time added to the time until RLF occurs, the time from RLF generation to gNB reselection and connection to the selected gNB occurs, and as a result the transmission speed for the terminal device is reduced. There is a risk that it will be lost. Therefore, the effect of shortening the reconnection time and improving the transmission speed by using RRC_inactive is reduced.

Further, in the conventional technology in which the source base station transmits to the terminal device information on the security key used for communication with the destination base station based on the security capability information received from the terminal device, the information is difficult to convey. Therefore, even with this conventional technique, it is difficult to improve the transmission speed. In addition, in the conventional technology that selects a security algorithm based on a distributed list of compatible security algorithms, it is difficult to transmit information to a terminal in the RRC_inactive state because of the notification of secure information. Therefore, it is difficult to improve the transmission speed using this conventional technique.

The disclosed technology has been made in view of the above, and aims to provide a terminal device, a wireless communication device, a wireless communication system, and a wireless communication method that improve transmission speed.

In one aspect of the terminal device, the wireless communication device, the wireless communication system, and the wireless communication method disclosed in the present application, the receiving unit includes a terminal-specific cell list in which security information for each cell possessed by each of a plurality of base stations is registered. is received from the AMF (Access and Mobility Management Function) . The selection unit selects a base station to be connected from among the plurality of base stations based on the first information. The transmitting unit transmits second information for resuming wireless connection to the selected base station.

According to one aspect of the terminal device, the wireless communication device, the wireless communication system, and the wireless communication method disclosed in the present application, it is possible to improve the transmission speed.

FIG. 1 is a system configuration diagram of a wireless communication system. FIG. 2 is a block diagram of a UE. FIG. 3 is a diagram showing an example of a terminal-specific cell list. FIG. 4 is a block diagram of a gNB. FIG. 5 is a block diagram of the AMF. FIG. 6 is a diagram showing an example of the format of the terminal-specific cell list. FIG. 7 is a sequence diagram of the reconnection process when the gNB that received the paging supports security algorithms that the UE can use. FIG. 8 is a sequence diagram of the reconnection process when the gNB receiving the page does not support the dark security algorithms that the UE can use. FIG. 9 is a sequence diagram of reconnection processing when the gNB to which the TAU is transmitted supports security algorithms that the UE can use. FIG. 10 is a sequence diagram of reconnection processing when the gNB to which the TAU is transmitted does not support the dark security algorithm that the UE can use. FIG. 11 is a sequence diagram of processing from network construction to UE becoming RRC_inactive. FIG. 12 is a hardware configuration diagram of AMF. FIG. 13 is a flowchart of cell list transmission stop processing in the wireless communication system according to the second embodiment. FIG. 14 is a flowchart of an example of customization processing for information registered in the terminal-specific cell list.

Embodiments of a terminal device, a wireless communication device, a wireless communication system, and a wireless communication method disclosed in the present application will be described below in detail with reference to the drawings. Note that the terminal device, wireless communication device, wireless communication system, and wireless communication method disclosed in the present application are not limited to the following embodiments. Also, the problems and examples in this specification are examples, and do not limit the scope of rights of the present application. In particular, even if the expressions in the description are different, as long as they are technically equivalent, the technology of the present application can be applied even if the expressions are different, and the scope of rights is not limited. Further, each embodiment can be appropriately combined within a range in which the processing contents are not inconsistent.

In addition, terms and technical contents used in this specification may appropriately use terms and technical contents described in specifications and publications as communication standards such as 3GPP.

FIG. 1 is a system configuration diagram of a wireless communication system. The radio communication system 100 includes UE 1 , AMF (Access and Mobility Management Function) 2 , gNB 3 , SMF (Session Management Function) 4 and UPF (User Plane Function) 5 . Here, there are multiple gNB3s.

UE1 is a terminal device, and performs data transmission by wireless communication with gNB3. For example, UE1 obtains tracking area information from AMF2 via gNB3. Next, UE1 selects a cell to connect from among the cells included in the tracking area, and connects to gNB3 that forms that cell. After that, UE1 communicates with other UE1 through the connected gNB3. The state in which this UE1 can communicate is a state called RRC_connected. Also, the UE1 periodically performs TAU to update the tracking area.

Moreover, UE1 changes a state from RRC_connected to RRC_inactive, when Inactive Timer and data communication frequency satisfy|fill a predetermined condition. When transitioning to RRC_inactive, the radio layer connection between UE1 and gNB3 is broken, but the upper layers remain connected. In addition, gNB3 and AMF2, which were connected last, hold the AS context of UE1. The AS context contains AS information such as security, including security algorithms.

The UE1 transmits location registration information (which may be referred to as location information) and receives a RAN area, which is a location registration area, from the AMF2 via the gNB3. The UE1 periodically executes RAU to update the RAN area. UE1 acquires the information of the RAN area and tracking area transmitted from AMF2 via gNB3.

Then, when transitioning from RRC_inactive to RRC_connected, UE1 establishes communication by reconnecting the radio layer by performing random access, establishment of radio synchronization, RRC configuration, etc. with gNB3 included in the RAN area. . The connection processing when transitioning from RRC_inactive to RRC_connected will be described later in detail.

AMF2 is a wireless communication device that performs mobility management in the C (control)-Plane. The AMF 2 performs registration and control of location registration information of the UE 1 . For example, AMF2 updates the tracking area of UE1 using the location information sent from UE1 by TAU. Also, the AMF 2 updates the RAN area of the UE1 using the location registration information transmitted from the UE1 by the RAU.

Also, the AMF 2 controls outgoing and incoming calls. In addition, AMF2 manages security information of UE1 and gNB3. Furthermore, when the TAU is received from UE1, AMF2 transmits tracking area information corresponding to the location information of UE1 to UE1 via gNB3. Further, when the AMF 2 receives the RAU from the UE 1, the AMF 2 transmits the RAN area information according to the location registration information of the UE 1 to the UE 1 via the gNB 3.

gNB3 is a radio base station that provides 5G radio. gNB3 performs data transfer by wireless communication with UE1. Moreover, gNB3 transmits the information of the RAN area and tracking area transmitted from AMF2 to UE1.

SMF4 is a communication control device that executes session management in the C-Plane. The SMF 4 controls session setup and release in wireless communication.

The UPF 5 performs communication control on the U (User)-Plane. UPF 5 processes data packets between the wireless communication network and the data network.

Next, the respective functions of UE1, gNB3 and AMF2 are described in detail. FIG. 2 is a block diagram of a UE.

As shown in FIG. 2, the UE 1 includes an RRC processing unit 11, a PDCP (Packet Data Convergence Protocol) processing unit 12, an RLC (Radio Link Control) processing unit 13, a MAC (Media Access Control) processing unit 14 and a PHY (Physical) It has a processing unit 15 . Furthermore, UE1 has a communication control unit 16 . In this embodiment, a case where a terminal-specific cell list for grasping the security algorithms that each gNB3 can use is sent to the UE1 at the time of paging (when calling or when notifying an incoming call) and when updating the tracking area will be described. However, the terminal-specific cell list may be sent to UE1 when updating the RAN area instead of when updating the tracking area.

The RRC processing unit 11 executes processing in the RRC layer such as system notification information distribution, paging distribution, NAS (Non Access Stratum) message distribution, RRC connection management, wireless security setting, and handover control. Also, the RRC processing unit 11 periodically transmits a location registration request to the AMF 2 . The location registration request is, for example, a TAU for updating the tracking area or an RAU for updating the RAN area. Furthermore, the RRC processing unit 11 has a cell selection control unit 111 and a security information management unit 112 .

The cell selection control unit 111 acquires a tracking area code representing a tracking area during paging or TAU. Cell selection control section 111 then acquires a terminal-specific cell list from SIB (System Information Block), which is system information (or system control information) included in the tracking area code.

FIG. 3 is a diagram showing an example of a terminal-specific cell list. The terminal-specific cell list 201 is a list in which gNB3 that can use algorithm A as a security algorithm is registered. For example, cell selection control section 111 can identify gNB 3 that can use algorithm A from terminal-specific cell list 201 . Here, cell selection control section 111 can confirm from terminal-specific cell list 201 that algorithm A can be used by gNB3 having cell ID #3. Also, the terminal-specific cell list 202 is a list in which gNB3 that can use algorithm B as a security algorithm is registered. For example, cell selection control section 111 can identify gNB 3 that can use algorithm B from terminal-specific cell list 202 . Here, cell selection control section 111 can confirm from terminal-specific cell list 202 that algorithm B can be used by gNB 3 having cell ID #1 or #2. Also, the terminal-specific cell list 203 is a list in which gNBs 3 that can use algorithm A or B as security algorithms are registered. For example, cell selection control section 111 can identify gNB 3 that can use algorithm A or B from terminal-specific cell list 203 . Here, cell selection control section 111 can confirm from terminal-specific cell list 203 that algorithm A or B can be used by gNB3 having cell IDs #1 to #3. Hereinafter, it is referred to as a terminal-specific cell list 200. FIG.

Next, the cell selection control unit 111 instructs the PHY processing unit 15 to measure the radio channel quality of gNB 3 registered in the terminal-specific cell list 200 . After that, the cell selection control unit 111 acquires the radio channel quality measurement result of each gNB 3 registered in the terminal-specific cell list 200 . Then, the cell selection control unit 111 selects the gNB 3 to be connected using the radio channel quality of each gNB 3, such as selecting the cell with the best radio channel quality. After that, the cell selection control section 111 outputs information on the selected gNB 3 and the terminal-specific cell list 200 to the security information management section 112 . This cell selection control unit 111 corresponds to an example of a “selection unit”. The terminal-specific cell list 200 corresponds to an example of "first information".

The security information management unit 112 holds security information including information on security algorithms that the UE 1 can use. The security information management unit 112 registers security algorithm information in UE capability (terminal performance information) transmitted to the gNB 3 to which the RRC processing unit 11 connects. Also, the security information management unit 112 creates an AS context including security keys and algorithms for data communication. Then, the security information management unit 112 transmits the AS context to the AMF 2 via the PDCP processing unit 12, the RLC processing unit 13, the MAC processing unit 14, the PHY processing unit 15 and the communication control unit 16 when the connection is established. Note that the terminal performance information does not change depending on external factors such as wireless channel quality, but is the performance of the terminal itself.

Also, the security information management unit 112 receives information on the gNB 3 selected as the connection destination and an input of the terminal-specific cell list 200 from the cell selection control unit 111 . Then, the security information management unit 112 uses the terminal-specific cell list 200 to specify a security algorithm that the gNB3 selected as the connection destination can use for communication with the UE1. Next, the security information management unit 112 determines a security algorithm to be used for communication with the gNB 3 selected as the connection destination. After that, the security information management unit 112 notifies the PDCP processing unit 12 of the security algorithm used for communication with the gNB 3 selected as the connection destination.

Also, the RRC processing unit 11 transmits an RRC Resume Request, which is a communication restart request, to the gNB 3 selected as a connection destination by the cell selection control unit 111 . After that, the RRC processing unit 11 receives RRC Resume from the connection destination gNB 3 , establishes a connection in the radio layer, and establishes a communication connection with the gNB 3 . This RRC processing unit 11 corresponds to an example of a “radio connection management unit”. Also, Resume Request corresponds to an example of "second information".

The PDCP processing unit 12 executes processing in the PDCP layer such as IP (Internet Protocol) packet header compression, decompression, and encryption. The PDCP processing unit 12 has a security control unit 121 .

The security control unit 121 performs signaling integrity assurance, encryption, and decryption. The security control unit 121 acquires the information of the security algorithm used for communication notified from the security information management unit 112 . Then, the security control unit 121 encrypts the data to be transmitted using the designated security algorithm and performs integrity assurance. Security control unit 121 also decrypts data input from RLC processing unit 13 using a designated security algorithm.

The RLC processing unit 13 performs processing in the RLC layer such as retransmission control, duplicate detection and reordering.

The MAC processing unit 14 executes MAC layer processing such as radio resource allocation, data mapping, and retransmission control. For example, the MAC processing unit 14 performs radio resource allocation and data mapping on the data input from the RLC processing unit 13 and outputs the data to the PHY processing unit 15 .

The PHY processing unit 15 performs processing in the PHY layer such as modulation and demodulation, encoding and decoding, antenna multiplexing, and quality measurement. For example, the PHY processing unit 15 performs demodulation processing and decoding processing on the signal input from the communication control unit 16 and outputs the processed signal to the MAC processing unit 14 . Also, the PHY processing unit 15 performs modulation processing and coding processing on the signal input from the MAC processing unit 14 and outputs the result to the communication control unit 16 .

The communication control unit 16 performs conversion between a PHY baseband signal and a radio signal. The communication control unit 16 transmits a radio signal to the connection destination gNB 3 . Also, the communication control unit 16 receives a radio signal from the gNB 3 to which it is connected. This communication control unit 16 corresponds to an example of a "receiving unit". Further, the communication control unit 16 may include a transmission unit (transmitter), a reception unit (receiver), or a communication unit (communication device).

Next, gNB3 will be described with reference to FIG. FIG. 4 is a block diagram of a gNB. The gNB 3 has an RRC processing unit 31 , a PDCP processing unit 32 , an RLC processing unit 33 , a MAC processing unit 34 , a PHY processing unit 35 , a communication control unit 36 and an SDAP (Service Discovery Adaptation Profile) processing unit 37 .

The RRC processing unit 31 executes processing in the RRC layer such as RRC connection management, wireless security setting and handover control. The RRC processing unit 31 has a security information management unit 311 . This RRC processing unit 31 corresponds to an example of a "connection control unit".

The security information management unit 112 holds security information including information on security algorithms that the gNB 3 can use. Also, when UE1 connects to gNB3, security information management unit 112 receives the AS context of connecting UE1 from AMF2. Then, when the connected UE1 is in the RRC_connected state or transitions to RRC_inactive, the security information management unit 112 holds the AS context of the UE1. That is, the security information management unit 112 holds security information including information on security algorithms that the UE 1 can use. Furthermore, the security information management unit 311 notifies the security control unit 321 of security information including security algorithm information included in the AS context of the UE1.

Further, the RRC processing unit 31 receives an RRC Resume Request from the UE1 when the UE1 in the RRC_inactive state selects the gNB3, which is the own device, as a connection destination in resuming communication. Then, the RRC processing unit 31 transmits a Retrieve AS Context Request, which is a request to acquire the AS context of the UE1, to the gNB3 that holds the AS context of the UE1, such as the anchor gNB. After that, the RRC processing unit 31 receives a Retrieve AS Context Response from the gNB 3 that transmitted the retrieval request. Then, the RRC processing unit 31 sets the cell formed by the gNB3, which is the own device, as the anchor cell or serving cell of the UE1. After that, the RRC processing unit 31 transmits RRC Resume to the UE1. After that, the RRC processing unit 31 establishes a radio layer connection with the UE1 and establishes a communication connection with the UE1.

The PDCP processing unit 32 performs processing in the PDCP layer such as IP packet header compression, decompression and encryption. The PDCP processor 32 has a security controller 321 . Further, the PDCP processing unit 32 receives input of IP packets transmitted from other gNB 3 and AMF 2 from the SDAP processing unit 37 . Also, the PDCP processing unit 32 outputs IP packets to be transmitted to other gNBs 3 and AMF 2 to the SDAP processing unit 37 .

The security control unit 321 performs signaling integrity assurance, encryption, and decryption. The security control unit 321 acquires the information of the security algorithm used for communication notified from the security information management unit 311 . Then, the security control unit 321 encrypts the data to be transmitted to the UE1 using the designated security algorithm and performs integrity assurance. Also, the security control unit 221 decrypts the transmission data from the UE 1 input from the RLC processing unit 33 using the designated security algorithm.

The RLC processing unit 33 performs processing in the RLC layer such as retransmission control, duplicate detection and reordering.

The MAC processing unit 34 executes processing in the MAC layer such as radio resource allocation, data mapping and retransmission control. For example, the MAC processing unit 34 performs radio resource allocation and data mapping on the data input from the RLC processing unit 33 and outputs the data to the PHY processing unit 35 .

The PHY processing unit 35 performs processing in the PHY layer such as modulation/demodulation, encoding/decoding, and antenna multiplexing. For example, the PHY processing unit 35 performs demodulation processing and decoding processing on the signal input from the communication control unit 16 and outputs the processed signal to the MAC processing unit 34 . Also, the PHY processing unit 35 performs modulation processing and coding processing on the signal input from the MAC processing unit 34 and outputs the result to the communication control unit 36 .

The communication control unit 36 performs conversion between PHY baseband signals and radio signals. The communication control unit 36 transmits a radio signal to the UE1 of the connection destination. Also, the communication control unit 16 receives a radio signal from the UE 1 to which it is connected.

The SDAP processing unit 37; It manages QoS (Quality Of Service) of user data. For example, the SDAP processing unit 37 receives IP packets received from the core network 6 from the PDCP processing unit 32 . Then, the SDAP processing unit 37 maps the obtained IP packet to a radio bearer corresponding to QoS and outputs it to the PDCP processing unit 32 . Further, the SDAP processing unit 37 maps the IP packet acquired from the PDCP processing unit 32 to a radio bearer corresponding to QoS, and outputs the mapped IP packet to the core network 6 .

Next, AMF2 will be described with reference to FIG. FIG. 5 is a block diagram of the AMF. As shown in FIG. 5, the AMF 2 has a communication control section 21, a mobility control section 22, a path control section 23, a base station control section 24, a cell list control section 25 and a security control section .

The communication control unit 21 transmits and receives data to and from the gNB3. The communication control unit 21 mediates communication between the gNB 3 and the mobility control unit 22 , the path control unit 23 and the base station management unit 24 . For example, the communication control unit 21 adds the terminal-specific cell list 200 of the paging destination UE 1 acquired from the cell list management unit 25 to the paging transmitted from the path control unit 23 and transmits the paging to the gNB 3 . This communication control unit 21 corresponds to an example of an "information receiving unit".

The path control unit 23 controls incoming and outgoing calls. For example, the path control unit 23 receives information on the tracking area and RAN area of the UE1 from the mobility control unit 22 . Also, the path control unit 23 receives a paging request from the gNB3. Next, the path control unit 23 determines a communication route to the paging destination UE 1 using the tracking area or the RAN area. Then, the path control unit 23 transmits paging to the gNB 3 on the determined communication path. Further, the path control unit 23 notifies the cell list management unit 25 of execution of paging when performing paging. At this time, the path control unit 23 notifies the cell list management unit 25 of information on the tracking area in which the UE1 is located.

The base station management unit 24 manages base station information including cell information in TA or RA units. The base station management unit 24 transmits a Cell Information Request, which is a notification request for cell information, to each gNB 3 when constructing the network. This Cell Information Request also includes a notification request for security algorithms that each gNB 3 can use. Thereafter, the base station management unit 24 receives cell information from each gNB3. Then, the base station management unit 24 notifies the security management unit 26 of the security algorithms that each gNB 3 can use.

Also, the base station management unit 24 sets the tracking area and the RAN area from the acquired cell information. Then, the base station management unit 24 outputs the tracking area and RAN area information to the mobility control unit 22 together with the cell information. Also, the base station management unit 24 outputs tracking area information to the cell list management unit 25 .

The mobility control unit 22 performs registration and control of location information of the UE1. Specifically, the mobility control unit 22 receives tracking area and RAN area information from the base station management unit 24 together with the cell information. Also, the mobility control unit 22 periodically receives a report of the area in which UE1 is located. Then, the mobility control unit 22 identifies the tracking area of the UE1. Also, when the UE1 is RRC_inactive, the mobility control unit 22 identifies the RAN area. Mobility control unit 22 notifies path control unit 23 of the tracking area and RAN area of UE1. Also, the mobility control unit 22 notifies the cell list management unit 25 of the update of the tracking area. At this time, the mobility control unit 22 notifies the cell list management unit 25 of information on the tracking area in which the UE1 is located.

The security management unit 26 receives the performance information transmitted from each UE1. Here, the performance information also includes information on security algorithms that each UE 1 can use. Based on this, the security management unit 26 generates AS context information for each UE1. The security management unit 26 also receives information on security algorithms that can be used by each gNB 3 from the base station management unit 24 . The security management unit 26 then stores information on security algorithms that can be used for each UE 1 and each gNB 3 .

Furthermore, the security management unit 26 generates each piece of UEAS context information based on the performance information of the UE1 establishing connection with the gNB3. The security management unit 26 then transmits the AS context information to the gNB 3 that establishes connection with the UE 1, and sets the AS context.

The cell list management unit 25 receives an input of tracking area information from the base station management unit 24 . Also, the cell list management unit 25 acquires information on the security algorithm of each gNB 3 from the security management unit 26 . Then, the cell list management unit 25 generates a terminal-specific cell list 200 for each security algorithm pattern for each tracking area. In this embodiment, the terminal-specific cell list 200 generates a white cell list indicating gNBs 3 that can be used for each security algorithm, or gNBs 3 that can use the security algorithms to enable line setup.

Here, the terminal-specific cell list 200 is patterned according to the number of algorithms used in 5G communication. Therefore, the process of creating the terminal-specific cell list 200 does not significantly impose the processes of the AMF 2 and gNB 3 . For example, if the number of security algorithms is 5, each security algorithm has two patterns of whether or not UE1 can use it, so there are 2^5-1=31 patterns of security algorithms that UE1 can use. That is, if the number of security algorithms is 5, there are 31 patterns for the terminal-specific cell list 200 created by the AMF 2 . In addition, since UE1 corresponds to at least one security algorithm, there are 31 types. If there is a case that does not correspond to any security algorithm, there are 32 ways.

Thereafter, when the cell list management unit 25 receives a paging execution notification from the path control unit 23 or receives a tracking area update notification from the mobility control unit 22, the cell list management unit 25 executes the following processing. The cell list management unit 25 acquires from the security management unit 26 information on security algorithms that can be used by the UE 1 whose paging, tracking area, or location registration area is to be updated. Then, the cell list management unit 25 selects a terminal-specific cell list 200 having a pattern corresponding to a security algorithm that can be used by the UE1 in the tracking area (location registration area) where the UE1 is located, and transmits the terminal-specific cell list 200 to the UE1. . The cell list management unit 25 corresponds to an example of an "information management unit".

Here, in this embodiment, the cell list management unit 25 uses a white cell list as the terminal-specific cell list 200 . However, the cell list management unit 25 may use a black cell list in which gNB 3 that does not support each security algorithm or gNB 3 that is difficult to set up because the security algorithm does not support is registered as the terminal individual cell list 200. good. When using the black cell list, UE 1 detects gNB 3 to which gNB 3 is connectable by performing radio channel quality measurement on gNB 3 excluding gNB 3 registered in acquired terminal-specific cell list 200 . In particular, if the number of gNB3s to be enabled for a particular algorithm in the tracking area or RAN area is small, the black cell list can provide less information.

Therefore, the cell list management unit 25 may determine whether the terminal-specific cell list 200 to be transmitted should be a white cell list or a black cell list, depending on the amount of information. In this case, the UE 1 determines whether the received terminal-specific cell list 200 is a white cell list or a black cell list. Therefore, the cell list management unit 25 preferably uses a terminal-specific cell list 200 in which a 1-bit identification flag 212 is added to the cell ID information 211 as shown in FIG. FIG. 6 is a diagram showing an example of the format of the terminal-specific cell list. By checking the identification flag 212 of the received terminal-specific cell list 200, the UE 1 can determine whether the cell ID information 211 is a white cell list or a black cell list.

Also, the cell list management unit 25 transmits the terminal-specific cell list 200 to the gNB 3 which is used for transmission of the TAU signal when the UE 1 moves or transmits the terminal-specific cell list 200 together with the paging. Here, it is conceivable that gNB3, which is used for paging and transmission of TAU signals, does not support the security algorithm used by UE1. Therefore, in this embodiment, unencrypted or common security algorithms are used for transmission of paging and TAU signals. A common algorithm is a security algorithm that is predetermined for use on the network.

Therefore, in this embodiment, the terminal-specific cell list 200 is transmitted either unencrypted or using encryption that is easy to decipher. In this respect, the terminal-specific cell list 200 only needs to include cell identification information. Also, the cell selected by UE1 has the highest line quality in the terminal-specific cell list 200, and cannot be easily identified by a third party. From these, it can be said that the terminal-specific cell list 200 does not contain secure information. Therefore, there is no problem even if the terminal-specific cell list 200 is transmitted by the cell list management unit 25 without being encrypted.

Also, in general, the same security algorithm may be used for C-plane and U-plane signals. However, if the security algorithm to be used is the same for the C-plane signal and the U-plane signal, and the C-plane signal such as the TAU signal is not encrypted or a common algorithm is used, the U-plane signal is the first. There is a risk of leakage to third parties. Therefore, in this embodiment, it is preferable to use different security algorithms for the C-plane signal and the U-plane signal.

Next, with reference to FIGS. 7 and 8, the flow of reconnection processing when transmitting the terminal-specific cell list 200 during paging will be described. FIG. 7 is a sequence diagram of the reconnection process when the gNB that received the paging supports security algorithms that the UE can use. Also, FIG. 8 is a sequence diagram of the reconnection process when the gNB that received the paging does not support the security algorithm that the UE can use. Here, UE1, gNB3A-3C, and AMF2 are assumed to be operating entities. gNB3C is an anchor gNB serving as a relay device in the C-plane connection. The tracking areas (location registration areas) of gNB3A and gNB3B are the same, but the tracking areas (location registration areas) of gNB3C are different. Also, in this example, gNBs 3A-3C all use AMF2, but this may also be different.

First, with reference to FIG. 7, reconnection processing when gNB3A that receives paging corresponds to a security algorithm that can be used by UE1 will be described. gNBs 3A-3C send their respective cell information to AMF2. Then, AMF 2 obtains cell information of gNBs 3A to 3C (step S101).

Next, UE1 starts random access by power-on or the like, and is attached to the network in which gNBs 3A to 3C and AMF 2 are arranged. After that, by satisfying a predetermined condition, the UE 1 transitions to the state of RRC_inactive (step S102).

After that, the UE 1 executes TAU or RAU processing and updates the tracking area, RAN area, or location registration area (step S103).

Thereafter, AMF2 receives a downlink signal addressed to UE1 (step S104).

Next, AMF2 confirms the UE context of UE1 (step S105).

Then, the AMF 2 creates the terminal-specific cell list 200 based on the security algorithm supported by the UE 1 (step S106).

Next, AMF2 transmits paging and terminal-specific cell list 200 to UE1 via gNB3C and 3A (step S107).

UE1 receives the paging (step S108). Furthermore, UE1 receives the terminal-specific cell list 200 together with paging.

Next, UE1 receives reference signals (RS) from gNBs 3A and 3B (steps S109 and S110).

Also, UE1 receives synchronization signals from gNBs 3A and 3B and identifies the cell IDs of gNBs 3A and 3B. Next, UE1 refers to terminal-specific cell list 200 and uses the specified cell ID to confirm that gNBs 3A and 3B are base stations that support security algorithms that UE1 can use. UE1 then performs radio channel quality measurement using the reference signals of gNBs 3A and 3B (step S111).

Next, the UE1 selects the cell formed by the gNB3A and the connection cell from the result of radio channel quality measurement (step S112).

Then, UE1 transmits RRC Resume Request, which is an RRC reconnection request, to gNB3A (step S113).

The gNB3A receives the RRC Resume Request and transmits a Retrieve UE Context Request, which is a transmission request for the UE context information of the UE1, to the gNB3C (step S114).

The gNB3C receives the Retrieve UE Context Request and transmits a Retrieve UE Context Response transmitting the context information of the UE1 to the gNB3A (step S115).

gNB3A receives the Retrieve UE Context Response and acquires the UE context of UE1. Then, gNB3A sets the cell to be formed by itself as the anchor cell or serving cell of UE1 (step S116).

The gNB 3A then transmits RRC Resume to the UE 1, establishes a radio connection, and establishes a communication connection with the UE 1 (step S117).

After that, UE1 and gNB3A transmit user data using the established communication connection (step S118).

Next, with reference to FIG. 8, the reconnection process when the gNB3A that received the paging does not support the security algorithm that the UE1 can use will be described. gNBs 3A-3C send their respective cell information to AMF2. Then, AMF 2 obtains cell information of gNBs 3A to 3C (step S201).

Next, UE1 starts random access by power-on or the like, and is attached to the network in which gNBs 3A to 3C and AMF 2 are arranged. After that, by satisfying a predetermined condition, the UE 1 transitions to the state of RRC_inactive (step S202).

After that, the UE 1 executes TAU or RAU processing and updates the tracking area, RAN area, or location registration area (step S203).

Thereafter, AMF2 receives a downlink signal addressed to UE1 (step S204).

Next, AMF2 checks the UE context of UE1 (step S205).

Then, the AMF 2 creates the terminal-specific cell list 200 based on the security algorithm supported by the UE 1 (step S206).

Next, AMF2 transmits paging and terminal-specific cell list 200 to UE1 via gNB3C and 3A (step S207).

UE1 receives the paging (step S208). Furthermore, UE1 receives the terminal-specific cell list 200 together with paging.

UE1 then receives reference signals from gNBs 3A and 3B (steps S209 and S210).

Also, UE1 receives synchronization signals from gNBs 3A and 3B and identifies the cell IDs of gNBs 3A and 3B. Next, UE1 refers to terminal-specific cell list 200 and uses the specified cell ID to confirm that gNB3B is a base station that supports security algorithms that UE1 can use, and that gNB3A does not. UE1 then performs radio channel quality measurement using the reference signal of gNB3B. In this case, UE1 does not measure the radio channel quality of the reference signal of gNB3B (step S211).

Next, the UE1 selects the cell formed by the gNB3B and the connected cell from the result of radio channel quality measurement (step S212).

The UE 1 then transmits an RRC Resume Request, which is an RRC reconnection request, to the gNB 3B (step S213).

The gNB3B receives the RRC Resume Request and transmits a Retrieve UE Context Request, which is a transmission request for the UE context information of the UE1, to the gNB3C (step S214).

The gNB3C receives the Retrieve UE Context Request and transmits a Retrieve UE Context Response transmitting the context information of the UE1 to the gNB3B (step S215).

gNB3B receives the Retrieve UE Context Response and acquires the UE context of UE1. The gNB 3B then sets the cell to be formed by itself as the anchor cell or serving cell of the UE 1 (step S216).

The gNB 3B then transmits RRC Resume to the UE 1 to establish a radio connection and establish a communication connection with the UE 1 (step S217).

After that, UE1 and gNB3B transmit user data using the established communication connection (step S218).

Next, with reference to FIGS. 9 and 10, the flow of reconnection processing when transmitting the terminal-specific cell list 200 at TAU will be described. FIG. 9 is a sequence diagram of reconnection processing when a gNB to which a TAU (location registration area update) is transmitted supports a security algorithm that can be used by the UE. Also, FIG. 10 is a sequence diagram of the reconnection process when the gNB to which the TAU is transmitted does not support the dark security algorithm that the UE can use.

First, with reference to FIG. 9, reconnection processing when the gNB 3A, which is the transmission destination of the TAU, supports a security algorithm that can be used by the UE 1 will be described. gNBs 3A-3C send their respective cell information to AMF2. Then, AMF 2 obtains cell information of gNBs 3A to 3C (step S301).

Next, UE1 starts random access by power-on or the like, and is attached to the network in which gNBs 3A to 3C and AMF 2 are arranged. After that, by satisfying a predetermined condition, the UE 1 transitions to the state of RRC_inactive (step S302).

After that, the UE1 moves across the tracking area (step S303).

Then, UE1 selects gNB3A that transmits/receives the C-plane signal without considering the security algorithm (step S304).

Next, UE1 transmits TAU to AMF2 via selected gNB3A (step S305).

AMF2 receives the TAU from UE1. AMF2 then updates the tracking area of UE1. Also, the AMF 2 checks the UE context (step S306).

Then, AMF 2 creates terminal-specific cell list 200 based on the security algorithm supported by UE 1 (step S307).

Next, AMF 2 transmits Tracking Area Update Accept, which is a tracking area (location registration area) update completion notification, and terminal-specific cell list 200 to UE 1 via gNB 3C and 3A (step S308).

The UE1 receives the Tracking Area Update Accept and the terminal-specific cell list 200 from the AMF2. UE1 then receives reference signals from gNBs 3A and 3B (steps S309 and S310).

Also, UE1 receives synchronization signals from gNBs 3A and 3B and identifies the cell IDs of gNBs 3A and 3B. Next, UE1 refers to terminal-specific cell list 200 and uses the specified cell ID to confirm that gNBs 3A and 3B are base stations that support security algorithms that UE1 can use. UE1 then performs radio channel quality measurement using the reference signals of gNBs 3A and 3B (step S311).

Next, the UE1 selects the cell formed by the gNB3A and the connection cell from the result of radio channel quality measurement (step S312).

Then, UE1 transmits RRC Resume Request, which is an RRC reconnection request, to gNB3A (step S313).

The gNB3A receives the RRC Resume Request and transmits a Retrieve UE Context Request, which is a transmission request for the UE context information of the UE1, to the gNB3C (step S314).

The gNB3C receives the Retrieve UE Context Request and transmits a Retrieve UE Context Response transmitting the context information of the UE1 to the gNB3A (step S315).

gNB3A receives the Retrieve UE Context Response and acquires the UE context of UE1. Then, gNB3A sets the cell to be formed by itself as the anchor cell or serving cell of UE1 (step S316).

The gNB 3A then transmits RRC Resume to the UE 1, establishes a radio connection, and establishes a communication connection with the UE 1 (step S317).

After that, UE1 and gNB3A transmit user data using the established communication connection (step S318).

Next, with reference to FIG. 10, reconnection processing when the gNB 3A as the transmission destination of the TAU does not support a security algorithm that can be used by the UE 1 will be described. gNBs 3A-3C send their respective cell information to AMF2. Then, AMF 2 obtains cell information of gNBs 3A to 3C (step S401).

Next, UE1 starts random access by power-on or the like, and is attached to the network in which gNBs 3A to 3C and AMF 2 are arranged. After that, by satisfying a predetermined condition, the UE 1 transitions to the state of RRC_inactive (step S402).

After that, the UE1 moves across tracking areas (or moves to a different tracking area) (step S403).

Then, UE1 selects gNB3A that transmits/receives the C-plane signal without considering the security algorithm (step S404).

Next, UE1 transmits TAU to AMF2 via selected gNB3A (step S405).

AMF2 receives the TAU from UE1. AMF2 then updates the tracking area of UE1. Also, the AMF 2 checks the UE context (step S406).

Then, AMF 2 creates terminal-specific cell list 200 based on the security algorithm supported by UE 1 (step S407).

Next, AMF 2 transmits Tracking Area Update Accept, which is a tracking area update completion notification, and terminal-specific cell list 200 to UE 1 via gNB 3C and 3A (step S408).

UE1 then receives reference signals from gNBs 3A and 3B (steps S409 and S410).

Also, UE1 receives synchronization signals from gNBs 3A and 3B and identifies the cell IDs of gNBs 3A and 3B. Next, UE1 refers to terminal-specific cell list 200 and uses the specified cell ID to confirm that gNB3B is a base station that supports security algorithms that UE1 can use, and that gNB3A does not. UE1 then performs radio channel quality measurement using the reference signal of gNB3B. In this case, UE1 does not measure the radio channel quality of the reference signal of gNB3B (step S411).

Next, UE1 selects a cell formed by gNB3B and a connection cell from the result of radio channel quality measurement (step S412).

The UE 1 then transmits an RRC Resume Request, which is an RRC reconnection request, to the gNB 3B (step S413).

The gNB3B receives the RRC Resume Request and transmits a Retrieve UE Context Request, which is a transmission request for the UE context information of the UE1, to the gNB3C (step S414).

The gNB3C receives the Retrieve UE Context Request and transmits a Retrieve UE Context Response transmitting the context information of the UE1 to the gNB3B (step S415).

gNB3B receives the Retrieve UE Context Response and acquires the UE context of UE1. Then, gNB3B sets the cell it forms as the anchor cell or serving cell of UE1 (step S416).

The gNB 3B then transmits RRC Resume to the UE 1, establishes a radio connection, and establishes a communication connection with the UE 1 (step S417).

After that, UE1 and gNB3B transmit user data using the established communication connection (step S418).

Here, with reference to FIG. 11, the process from network construction to UE1 becoming RRC_inactive will be described in detail. FIG. 11 is a sequence diagram of processing from network construction to UE becoming RRC_inactive.

AMF 2 transmits a Call Information Request, which is a notification request for cell information, to gNBs 3A-3C (step S501). Here, the Call Information Request also includes a notification request for security algorithms that can be used by each of the gNBs 3A to 3C.

The gNBs 3A to 3C then transmit cell information including information on security algorithms that can be used by each to the AMF 2 (step S502).

Next, the AMF 2 creates a terminal-specific cell list 200 for each pattern (step S503).

UE1 then performs random access to gNBs 3A-3C. UE1 then transmits the UE context and sets the UE context of UE1 in gNBs 3A-3C (step S504).

Next, UE1 transmits UE performance information including the security algorithm of UE1 to AMF2 (step S505).

After that, when the location registration timing according to the location registration period arrives, the UE1 transmits the TAU or the location information to the AMF (step S506).

gNB3C transmits a paging notification to UE1 by Paging occasion (step S507).

After that, AMF2 generates each UEAS context information based on the UE performance information of UE1. The security management unit 26 then transmits the AS context information to the connected base station among the gNBs 3A to 3B to set the AS context (step S508).

UE1 transitions to RRC_connected (step S509).

After that, UE1 and the base station to be connected among gNB3A-3B perform radio channel release and UE context release when a specific condition is satisfied (step S510).

Then, UE1 transitions to RRC_inactive (step S511).

Next, the hardware configuration of AMF2 will be described. FIG. 12 is a hardware configuration diagram of AMF. As shown in FIG. 12 , the AMF 2 has a CPU (Central Processing Unit) 291 , memory 292 , hard disk 293 and communication interface 294 . The CPU 291 is connected to a memory 292, a hard disk 293 and a communication interface 294 via a bus. CPU 291 communicates with memory 292, hard disk 293 and communication interface 294 via a bus.

The communication interface 294 is an interface for communication between the communication control unit 21 and the gNB3.

The hard disk 293 stores various programs including programs for realizing the functions of the communication control unit 21, the mobility control unit 22, the path control unit 23, the base station control unit 24, the cell list control unit 25, and the security control unit 26 illustrated in FIG. to store

The CPU 291 reads out various programs from the hard disk 293, develops them in the memory 292, and executes them, thereby controlling the communication control unit 21, the mobility control unit 22, the path control unit 23, the base station management unit 24, the cell list management unit 25, and the security program. It implements the functions of the management unit 26 .

Here, in the above description, the case where UE 1 acquires terminal-specific cell list 200 from AMF 2 when performing TAU has been described, but this terminal-individual cell list 200 may be acquired at another timing. For example, the configuration may be such that the terminal-specific cell list 200 is acquired from the AMF 2 when the UE 1 performs RAU. Even when the terminal-specific cell list 200 is acquired at the timing of RAU, the UE1, gNB3 and AMF2 perform the same processing as the above-described processes only with different acquisition timings.

As described above, the UE according to this embodiment acquires information for determining the security algorithms available to the gNBs to which it can connect. Then, when the UE reconnects to the gNB in the RRC_inactive state, the UE establishes a connection with a gNB selected from gNBs whose available security algorithms match those of the UE itself. As a result, it is possible to avoid connection failure due to security algorithm mismatch at the time of reconnection from the RRC_inactive state, and reduce the occurrence of RLF. Therefore, it is possible to reduce the occurrence of communication interruptions for the time until the occurrence of RLF and the time from the occurrence of RLF to gNB reselection, and improve the transmission speed. In addition, it is possible to make full use of the advantage of using RRC_inactive.

Next, Example 2 will be described. UE1, gNB3 and AMF2 according to this embodiment are also represented in FIGS. 2, 4 and 5, respectively. The UE 1 according to this embodiment differs from the first embodiment in that the transmission of the terminal-specific cell list 200 from the AMF 2 is stopped in a predetermined case. In the following description, the description of the operation of each unit similar to that of the first embodiment will be omitted.

The security control unit 121 of the UE 1 acquires information on the security algorithm to be used from the security information management unit 112 when changing the security algorithm to be used due to a change in the service provided. Then, when changing the security algorithm to be used, the security control unit 121 transmits a cell list transmission stop request to the AMF 2 via the gNB 3 .

The cell list management unit 25 of AMF2 receives the cell list transmission stop request from UE1. After that, the cell list management unit 25 stops transmitting the terminal-specific cell list 200 to the UE1 at the time of TAU.

FIG. 13 is a flowchart of cell list transmission stop processing in the wireless communication system according to the second embodiment.

The UE 1 changes the service to be used according to an instruction from the user (step S601).

Next, UE1 changes the security algorithm to be used (step S602).

Next, UE1 transmits a cell list transmission stop request to AMF2 via gNB3 (step S603).

AMF2 receives the cell list transmission stop request. AMF 2 then transmits ACK, which is a reception response to the cell list transmission stop request, to UE 1 (step S604). After this, AMF 2 stops transmitting terminal-specific cell list 200 to UE 1 .

As explained above, the UE according to the present embodiment stops receiving the individual terminal cell list when the service to be used is changed. As a result, it is possible to reduce unnecessary communications, and it is possible to omit the confirmation process of the security algorithm that causes a mismatch, so that the transmission speed can be improved.

(Modification)
Furthermore, in each of the above embodiments, identification information of gNB3 corresponding to a security algorithm that can be used by UE1 is registered in the terminal-specific cell list 200, but in addition to this, other information is registered in the terminal-specific cell list 200. may be For example, information registered in the terminal-specific cell list 200 may be customized upon request from the UE1 side.

For example, the security control unit 121 of the UE 1 receives an instruction from the user and notifies the AMF 2 of information to be additionally registered in the terminal-specific cell list 200 .

The cell list management unit 25 of the AMF 2 acquires information to be additionally registered in the terminal-specific cell list 200 transmitted from the UE1. Then, the cell list management unit 25 registers the information specified when the terminal-specific cell list 200 is created in addition to the identification information of the gNB 3 corresponding to the security algorithms that the UE 1 can use.

FIG. 14 is a flowchart of an example of customization processing for information registered in the terminal-specific cell list. Here, a case of additionally registering information on a corresponding security algorithm will be described as an example.

UE1 transmits a cell list customization request for adding security algorithm information to AMF2 via gNB3 (step S611).

AMF2 receives the cell list customization request. The AMF 2 then transmits ACK, which is a reception response to the cell list customization request, to the UE 1 (step S612). In addition to the identification information of gNB3, AMF2 registers the information of the security algorithm which each gNB3 corresponds to the terminal individual cell list 200, and transmits it to UE1.

1 UE
2 AMF
3 gNBs
4 SMFs
5 UPF
11 RRC processing unit 12 PDCP processing unit 13 RLC processing unit 14 MAC processing unit 15 PHY processing unit 16 Communication control unit 21 Communication control unit 22 Mobility control unit 23 Path control unit 24 Base station management unit 25 Cell list management unit 26 Security management unit 31 RRC processing unit 32 PDCP processing unit 33 RLC processing unit 34 MAC processing unit 35 PHY processing unit 36 Communication control unit 111 Cell selection control unit 112 Security information management unit 121 Security control unit 100 Wireless communication system 200 to 203 Terminal-specific cell list 311 Security information management unit 321 Security control unit

Claims (7)

a receiving unit that receives from an AMF (Access and Mobility Management Function) a terminal-specific cell list in which information about security for each cell possessed by each of a plurality of base stations is registered ;
a selection unit that selects a base station to be connected from the base station based on the terminal-specific cell list ;
and a wireless connection manager that transmits second information for resuming wireless connection to the selected base station. 2. The terminal device according to claim 1, wherein the terminal-specific cell list is information for selecting a base station compatible with a security algorithm compatible with the terminal device. 2. The terminal device according to claim 1, wherein the receiving unit receives the terminal-specific cell list from the AMF when receiving an incoming call. The wireless connection management unit requests the AMF to update the location registration information,
2. The terminal apparatus according to claim 1, wherein said receiving unit receives said terminal-specific cell list as a response to a request for update of location registration information by said wireless connection managing unit. an information receiving unit that receives security information of the terminal device from the terminal device;
an information management unit that generates a terminal-individual cell list indicating base stations having cells compatible with the security algorithm included in the security information, and transmits the generated terminal- individual cell list to the terminal device; A wireless communication device characterized by: A wireless communication system comprising a terminal device, an AMF and a plurality of base stations,
The terminal device
a receiving unit that receives from the AMF a terminal-specific cell list indicating the base station that has cells that can support a security algorithm included in the security information of the terminal device;
a selection unit that selects a base station to be connected from among the base stations based on the terminal-specific cell list ;
a wireless connection management unit that transmits second information for resuming wireless connection to the selected base station;
The AMF is
an information management unit that receives security information of the terminal device, generates the terminal-specific cell list, and transmits the generated terminal-specific cell list to the terminal device;
The base station
A wireless communication system comprising a connection control unit that receives the second information from the terminal device and establishes a connection with the terminal device. A wireless communication method in a terminal device, an AMF and a plurality of base stations, comprising:
causing the terminal device to transmit security information of the terminal device to the AMF ;
causing the AMF to generate a terminal-specific cell list indicating the base stations having cells compatible with the security algorithm included in the security information of the terminal device acquired from the terminal device, and to transmit the list to the terminal device;
causing the terminal device to receive the terminal-individual cell list communicated from the AMF , select a connecting base station to be connected from the base station based on the terminal- individual cell list , and wirelessly connect to the connecting base station. cause the second information to be sent to resume the
A wireless communication method, comprising causing the connecting base station to acquire the second information and establishing a connection with the terminal device according to security information of the terminal device.

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