JP2016103778A - Communication system, communication method, and connection processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten time until a terminal connects a network in a good communication state.SOLUTION: A communication system has a base station, an access point, and a server. The base station is used for connection to a first network. The access point is used for connection to a second network. The server determines a priority of a connection destination, for each of the terminals which can connect to the base station and connect to the access point. The communication system includes acquisition means and notification means. The acquisition means, when receiving a start request of communication through a first network from a target terminal being a terminal positioned in a cell formed by the base station, acquires the priority applied to the target terminal from the server, when the target terminal to the first network is not connected. The notification means notifies the priority applied to the target terminal together with refusal of the connection to the target terminal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a communication system, a communication method, and a connection processing device used for terminal communication.

  In a system including a plurality of networks, an ANDSF (Access Network Discovery and Selection Function) may be used to guide a terminal to connect to a network with good communication conditions. The ANDSF server notifies each terminal in communication of the policy information indicating the priority of the connection destination of the terminal by the user plane. The terminal communicates using a network having a good communication status according to the policy information. On the other hand, the ANDSF server appropriately updates policy information applied to each terminal in response to a change in the status of each network.

  As a related technique, a distribution device that holds a correspondence relationship between an access point and a cell of a mobile communication network and receives information specifying the cell is transmitted to the mobility management device. Proposed. When the distribution device receives a list of terminals located in the specified cell and has established a control link with the mobility device, the distribution device receives an access point in the cell where the terminal is located in the list. The discovery information including the information indicating is notified (for example, Patent Document 1). In addition, there is a server that generates a policy to be applied to a terminal under the base station when policy generation is requested, and transmits the generated policy to the terminal under the base station that has requested the policy generation. It has been proposed (for example, Patent Document 2).

JP 2013-225771 A JP 2013-38477 A

  Since the network status changes from moment to moment, it is desirable for the terminal to obtain policy information generated based on the latest status of each network. However, the terminal may not be able to acquire policy information because the terminal has disconnected communication. In addition, a policy applied to a terminal may be updated in the ANDSF server even though the terminal cannot acquire policy information due to a change in the network status. In this case, since the terminal tries to connect to the network selected according to the policy information before update when connecting to the network, it takes time to connect to the appropriate network. Connection delay due to a mismatch between the system status and the policy information held by the terminal may occur even in systems other than those using ANDSF.

  This problem cannot be solved even if the technology described as the related technology is applied. In the method of notifying discovery information using a list of terminals that have established a control link, policy information cannot be notified to a terminal that has not established a link. Also, in the method of transmitting the policy generated upon request via the base station, the same policy is transmitted for each base station, so that congestion is caused by all the terminals under the base station trying to connect to the same network. It takes time to establish communication.

  An object of the present invention is to shorten the time required for a terminal to connect to a network with good communication conditions.

  In one certain aspect, a communication system is provided with a base station, an access point, and a server. The base station is used for connection to the first network. The access point is used for connection to the second network. The server determines the priority of the connection destination for each terminal that can connect to the base station and connect to the access point. The communication system also includes an acquisition unit and a notification unit. When the acquisition unit receives a communication start request via the first network from the target terminal that is a terminal located in a cell formed by the base station, the acquisition unit applies to the target terminal when the target terminal is not connected to the first network. Get priority to be used from server. The notifying means notifies the target terminal of the priority applied to the target terminal together with the rejection of the connection.

  The time until the terminal connects to a network with good communication conditions is shortened.

It is a figure explaining the example of the communication method concerning embodiment. It is a figure explaining the example of a communication system. It is a figure explaining the example of a structure of a base station. It is a figure explaining the example of the hardware constitutions of a base station. It is a figure explaining the example of a structure of a server. It is a figure explaining the example of the hardware constitutions of a server. FIG. 10 is a sequence diagram illustrating an example in which policy information does not match between a terminal and a server when access restriction occurs while the terminal disconnects communication. It is a figure which shows the example of policy information. It is a figure which shows the example of access control information. It is a sequence diagram which shows the example of the connection process concerning 1st Embodiment. It is a figure which shows the example of a format of a connection rejection message. It is a flowchart explaining the example of the reception process of the communication start request | requirement under access control. It is a flowchart explaining the example of operation | movement of the server from which policy information was requested | required. It is a flowchart explaining the example of the transmission process of a connection rejection message. It is a flowchart explaining the example of the process performed with the terminal by which connection was refused. It is a sequence diagram explaining the example of the processing delay avoided by 1st Embodiment. It is a sequence diagram explaining an example in case policy information becomes inconsistent with a terminal and a server by the failure which generate | occur | produced during the cutting | disconnection of communication. It is a sequence diagram which shows the example of the connection process concerning 2nd Embodiment. It is a figure which shows the example of the determination information concerning 2nd Embodiment. It is a flowchart explaining the example of operation | movement of the server concerning 2nd Embodiment. It is a flowchart explaining the example of a reception process of a connection rejection notification request. It is a flowchart explaining the example of a reception process of a communication start request. It is a sequence diagram explaining the example of the processing delay avoided by 2nd Embodiment. It is a figure which shows the example of a structure of a wireless network control apparatus. It is a figure explaining the example of the return process to reconnection or communication. It is a sequence diagram explaining the example of the process performed in the case of reconnection.

  FIG. 1 is a diagram illustrating an example of a communication method according to the embodiment. FIG. 1 shows an example of processing performed when the base station 20 does not permit connection to the terminal 10. The system to which the communication method shown in FIG. 1 is applied includes a cellular network and a non-cellular network. The cellular network is a network compatible with 3GPP (Third Generation Partnership Project). The cellular network is used for communication using LTE (Long Term Evolution), 3G (generation), 4G, and the like. On the other hand, the non-cellular network is a network that does not support 3GPP, such as a WLAN (Wireless Local Area Network) network, a WiMAX (Worldwide Interoperability for Microwave Access) network, and a WiFi (Wireless Fidelity) network. The terminal 10 can be connected to either a cellular network or a non-cellular network. However, at the start of communication, the terminal 10 is set to use the cellular network preferentially.

In step S <b> 1, the terminal 10 transmits a communication start request to the base station 20.
In step S <b> 2, the base station 20 transmits, to the server 50, a request for policy information applied to the terminal 10 together with information on the terminal 10 that has transmitted the communication start request. Here, the base station 20 requests policy information from the server 50 when the connection with the terminal 10 is not established. For example, when access control to the cellular network has occurred and the base station 20 has already decided not to connect with the new terminal 10, the base station 20 sends a request to the terminal 10 that has requested the start of communication. The server 50 is inquired about policy information to be applied. The policy information is information indicating which of the base station 20 and the access point 70 is given priority as the connection destination of the terminal 10 for each terminal 10.

  In step S <b> 3, it is assumed that the server 50 transmits information indicating that the access point (AP) 70 is given priority as a connection destination of the terminal 10 to the base station 20. In this case, communication using the non-cellular network 15 is prioritized over communication using the cellular network 1.

  In step S4, the base station 20 rejects the connection of the terminal 10 to the base station 20, and generates a connection rejection message including policy information applied to the terminal 10 (step S4). Here, it is assumed that the connection rejection message includes policy information indicating that the non-cellular network has priority over the cellular network. The base station 20 transmits a connection rejection message to the terminal 10 (step S5).

  In step S6, the terminal 10 updates the policy information stored in the terminal 10 based on the policy information in the connection rejection message received from the base station 20, and the access point 70 based on the updated policy information. Decide to connect to. Therefore, the terminal 10 transmits a connection request to the access point 70 in order to attempt connection to the non-cellular network (step S7). When the terminal 10 successfully establishes communication with the access point 70, the terminal 10 performs communication processing using the non-cellular network via the access point 70 (step S8).

  As described above, in the communication method according to the embodiment, when the base station 20 rejects establishment of communication with the terminal 10, the base station 20 notifies the policy information applied to the terminal 10. For this reason, since the terminal 10 can change a connection destination based on the policy information notified by the connection rejection message, the terminal 10 can be connected to a network having a good communication state in a short time.

  In FIG. 1, the case where two connection destinations from the terminal 10 are the base station 20 and the access point 70 has been described as an example, but three or more request destinations may be used. For example, when there are a plurality of networks having different communication speeds in the non-cellular network 15, the terminal 10 uses the access point 70 of each network in the non-cellular network 15 as the transmission destination of the connection start request. Can do. Also in this case, the policy information is information representing the priority order of each network as a connection destination of the terminal 10.

  In FIG. 1, the case where the base station 20 acquires a policy or transmits a connection rejection message has been described, but these processes are arbitrary connection processes that perform a connection process between the cellular network 1 and the terminal 10. It can be done by the device. The connection processing device includes devices such as the base station 20 and a radio network controller (Radio Network Controller, RNC).

<Device configuration>
FIG. 2 is a diagram illustrating an example of a communication system. The communication system includes a cellular network 1, a non-cellular network 15, and a server 50. The server 50 is connected to both the cellular network 1 and the non-cellular network 15. In the example of FIG. 2, the cellular network 1 includes a NodeB 4, an eNodeB (Evolved Node B) 3, a HeNB (Home eNodeB) 2, a maintenance management device 6, a subscriber information management device 7, and an RNC 80. Hereinafter, the term “base station” indicates any one of HeNB2, eNodeB3, and NodeB4. Note that both the HeNB 2 and the eNodeB 3 communicate with both the terminal 10 and the server 50. The RNC 80 communicates with the server 50 and further communicates with the terminal 10 via the NodeB 4.

  The maintenance management device 6 transmits a status notification for notifying the status change that has occurred in the cellular network 1 to the server 50. For example, the maintenance management device 6 transmits a control message for restricting access to the cellular network 1 to the server 50. The maintenance management device 6 also performs processing for maintenance and management of the cellular network 1. Note that the maintenance management device 6 and the subscriber information management device 7 may not be included in the cellular network 1 like the server 50. The subscriber information management device 7 stores the contract information of the user of the terminal 10 in association with the identifier of the terminal 10. The subscriber information management device 7 can be, for example, an HSS (Home Subscriber Server) or an HLS (Home Location Register). When the use authority (subscriber class) of the subscriber is classified according to the contract content, the subscriber information management device 7 stores the subscriber class in association with the identification information of the terminal 10. In the following description, it is assumed that the subscriber class is recorded in the subscriber information management device 7 in association with the IMSI or TMSI of the terminal 10.

  In the example of FIG. 2, the case where the terminal 10a and the terminal 10b are connected to the cellular network 1 and the terminal 10c and the terminal 10d are connected to the non-cellular network 15 is illustrated, but the terminal 10 connected to each network is illustrated. The number is arbitrary. Any terminal 10 is assumed to be a device that can be connected to both the cellular network 1 and the non-cellular network 15 such as a mobile phone device including a smartphone and a tablet.

  FIG. 3 shows an example of the configuration of the base station 20. For example, the HeNB 2 and the eNodeB 3 operate as the base station 20. The base station 20 includes a wireless communication processing unit 23, a communication unit 24, a control unit 30, and a storage unit 40. The wireless communication processing unit 23 includes a reception unit 21 and a transmission unit 22. The control unit 30 includes an acquisition processing unit 31, a notification unit 32, a determination unit 33, and a connection processing unit 34. The storage unit 40 stores policy information 41 and determination information 42.

  The receiving unit 21 receives a signal such as a communication start request from the terminal 10. The transmission unit 22 transmits a signal such as a connection rejection message to the terminal 10. The communication unit 24 is used for communication between the terminal 10 and the server 50.

  The determination unit 33 determines whether to establish a connection with the terminal 10 that has requested the start of communication. For example, when access restriction is performed, the determination unit 33 determines that connection is not established for the terminal 10 that has requested connection to the base station 20. The determination unit 33 stores the determination result as determination information 42 in the storage unit 40. If the connection with the terminal 10 that has requested the start of communication is not established, the acquisition processing unit 31 requests the server 50 for policy information applied to the terminal 10 that has requested the start of communication. . The notification unit 32 stores the policy information received from the server 50 in the storage unit 40 as policy information 41 and performs notification processing for notifying the terminal 10. The connection processing unit 34 performs connection processing with the terminal 10 when establishing a connection with the terminal 10 that has requested the start of communication.

  FIG. 4 shows an example of the hardware configuration of the base station 20. The base station 20 includes a processor 101, a RAM (Random Access Memory) 102, a ROM (Read Only Memory) 103, an external storage device 104, a bus 105, a network interface 106, and a wireless network interface 107. The processor 101 is an arbitrary processor including a central processing unit (CPU), and operates as the control unit 30. At this time, the processor 101 performs processing by reading a program such as firmware stored in the ROM 103 or the external storage device 104. The RAM 102 holds data used for processing by the processor 101 and operates as the storage unit 40. The bus 105 connects the processor 101, the RAM 102, the ROM 103, the external storage device 104, the network interface 106, and the wireless network interface 107 so that data can be input and output mutually. The network interface 106 operates as the communication unit 24, and the wireless network interface 107 operates as the wireless communication processing unit 23.

  FIG. 5 shows an example of the configuration of the server 50. The server 50 includes a transmission / reception unit 55, an update unit 53, an extraction unit 54, and a storage unit 60, and operates as an ANDSF server, for example. The transmission / reception unit 55 includes a reception unit 51 and a transmission unit 52. The storage unit 60 stores policy information 61, access restriction information 62, and access point information 63. The receiving unit 51 receives data from the base station 20, the maintenance management device 6, the subscriber information management device 7, and the like. The transmission unit 52 transmits data to the base station 20 and the like. The updating unit 53 updates the policy information 61 for each terminal using the information received from the maintenance management device 6 and the base station 20, the information received from the subscriber information management device 7, the access point information 63, and the like. The access point information 63 is information in an arbitrary format in which for each base station 20, information on an access point 70 in which a communication area overlaps with the position of a cell formed by the base station is associated. The access restriction information 62 is information indicating whether access restriction is performed and the degree of access restriction in association with information indicating a position in the cellular network 1. The extraction unit 54 extracts the policy information received from the base station 20 from the policy information 61 and notifies the base station 20 via the transmission unit 52.

  FIG. 6 shows an example of the hardware configuration of the server 50. The server 50 includes a processor 101, a RAM 102, a ROM 103, an external storage device 104, a bus 105, and a network interface 106. The processor 101 operates as the update unit 53 and the extraction unit 54 using a program stored in the ROM 103 or the external storage device 104. The RAM 102 operates as the storage unit 60. The network interface 106 operates as the reception unit 51 and the transmission unit 52.

<First Embodiment>
Hereinafter, an example of communication processing performed when access restriction occurs while the terminal 10 is disconnected from communication will be described.

  FIG. 7 is a sequence diagram for explaining an example in which policy information does not match between the terminal 10 and the server 50 when access restriction occurs while the terminal 10 is disconnected from communication. In the following description, it is assumed that the terminal 10 can be connected to any of the base station 20, the access point 70a, and the access point 70b. Base station 20 is included in cellular network 1, and access points 70 a and 70 b are included in non-cellular network 15. Further, it is assumed that the communication via the access point 70a has a higher throughput than the communication via the access point 70b.

  In step S <b> 11, the terminal 10 performs communication via the base station 20. In step S <b> 11, communication using the user plane is performed between the terminal 10 and the server 50. For this reason, the terminal 10 receives policy information 61 a applied to the terminal 10 from the server 50 using a session between the terminal 10 and the server 50. Further, the connection destination list 11 a held by the terminal 10 is updated to be the same information as the information received from the server 50. For this reason, the information in the connection destination list 11a and the policy information 61a coincide with each other during communication of the terminal 10 (step S12). At this time, in both the policy information 61a and the connection destination list 11a, the priority of the connection destination of the terminal 10 is in the order of the base station 20 (communication using the cellular network 1), the access point 70b, and the access point 70a. Shall. In the policy information 61 and the connection destination list 11, it is assumed that the information regarding the base station 20 records that the cellular network 1 is specified instead of the identifier of the base station 20 itself. Further, in the drawings, an access point may be described as “AP”, and a cellular network may be described as “cellular network”. Further, in the connection destination list 11, a black circle is shown in front of the target to be connected in order to make it easy to understand the target to which the terminal 10 is trying to connect.

  In step S13, it is assumed that the terminal 10 has disconnected communication via the base station 20. Along with the disconnection of communication, the session between the terminal 10 and the server 50 is also disconnected. After the session between the terminal 10 and the server 50 is disconnected, it is assumed that the maintenance management device 6 determines to restrict access to the cellular network 1 as the access to the cellular network 1 increases (step S14). Access control may be performed to prevent congestion due to factors such as the occurrence of a disaster, the holding of an event, and the year-end and New Year holidays. The maintenance management device 6 transmits information (access restriction notification) for notifying access restriction to the cellular network 1 to the server 50 (step S15). In addition, the maintenance management device 6 shall notify the base station 20 and a radio network controller (Radio Network Controller, RNC), etc. of information related to access control as appropriate in order to implement access control.

  When the update unit 53 of the server 50 obtains the access restriction notification via the reception unit 51, the update unit 53 identifies the access point 70 with which the communication area overlaps for each sector, and changes the policy information 61 using the access point information 63. To do. Here, it is assumed that the policy information 61a applied to the terminal 10 is updated to the policy information 61b. That is, the server 50 sets the priority of the connection destination of the terminal 10 in the order of the access point 70b, the access point 70a, and the base station 20. Furthermore, the update unit 53 also updates the access restriction information 62. At this time, since the communication between the terminal 10 and the server 50 is disconnected, the server 50 does not transmit the information in the policy information 61b to the terminal 10. Therefore, in the connection destination list 11a, the connection destination of the terminal 10 remains in the order of the base station 20, the access point 70b, and the access point 70a in descending order of priority, and the information in the connection destination list 11a is the policy information 61b. (Step S16).

  FIG. 8 is a diagram illustrating an example of the policy information 61. The policy information 61a and the policy information 61b described with reference to FIG. 7 are excerpted from information applied to the terminal 10 for easy understanding of the description. However, since the server 50 has information about each of the terminals that can access both the cellular network 1 and the non-cellular network 15, the policy information 61 can be expressed as shown in FIG. When the policy information 61 shown in FIG. 8 is used, the priority of the connection destination is determined for each combination of base station, sector, carrier, and subscriber class. A combination of a base station, a sector, and a carrier is information used for designating an area where each terminal 10 is located. The update unit 53 determines whether to make the cellular network 1 the highest priority network using the combination of the base station, the sector, and the carrier and the access restriction information 62 (FIG. 9). Furthermore, the update unit 53 uses the access point information 63 to identify access points 70 that can be selected as connection destinations. The subscriber class is a value set according to the contents of the user contract. The updating unit 53 updates the policy information 61 so that the higher the subscriber class, the higher the priority of the access point 70 of the network with the higher throughput. In the example of FIG. 8, in a normal class user terminal that has transmitted a communication start request including a combination of BTS [0], sector [1], and carrier [1], the priority of the connection destination is the access point 70b, access The points 70a and the base station 20 are arranged in this order. On the other hand, in a user terminal of a priority class that has transmitted a communication start request including a combination of BTS [0], sector [1], and carrier [1], the priority order of connection destinations is access point 70a, access point 70b, base It becomes the order of the station 20.

  FIG. 9 is a diagram illustrating an example of the access restriction information 62. The access restriction information 62 includes base station information, sector information, carrier information, and percentage restriction information. Percent restriction information indicates the ratio of the number of connections to be failed by access restriction to the number of terminals 10 that can be connected when there is no access restriction. For example, when the percentage restriction information = 0%, it indicates that no access restriction has occurred. On the other hand, when the percentage restriction information = 80%, it is set that 80% of terminals that can be connected to the base station 20 are not permitted to be connected when there is no access restriction. Also in the access restriction information 62, a combination of a base station, a sector, and a carrier is used for designating an area where restriction is performed.

  FIG. 10 is a sequence diagram illustrating an example of connection processing according to the first embodiment. Case C1 in FIG. 10 is an example of processing when the terminal 10 accesses the cellular network 1 via the base station 20, and Case C2 is processing after the terminal 10 changes the connection destination to the non-cellular network 15. It is an example.

  Since the base station 20 is given the highest priority as the connection destination in the connection destination list 11a held by the terminal 10 at the time of step S21, the terminal 10 transmits a communication start request to the base station 20. It is assumed that the communication start request includes identification information of the terminal 10 such as IMSI (International Mobile Subscriber Identity) and TMSI (Temporary Mobile Subscriber Identity). For example, RRC CONNECTION REQUEST is used as the communication start request. The determination unit 33 of the base station 20 acquires a communication start request via the reception unit 21. The determination unit 33 determines to reject the communication start request from the terminal 10 according to access restrictions.

  Since the acquisition processing unit 31 determines that the communication start request from the terminal 10 is rejected, the acquisition processing unit 31 generates a policy information request to request the policy information of the terminal 10 from the server 50. The policy information request includes the IMSI or TMSI of the terminal 10 that requests the policy, and the cell ID that represents the location of the terminal 10. Here, the cell ID is a value obtained by combining the identification numbers of the base station, the sector, and the carrier that cover the position of the terminal 10 that is the transmission source of the communication start request. The acquisition processing unit 31 transmits a policy information request to the server 50 via the communication unit 24 (step S22).

  In step S <b> 23, the extraction unit 54 of the server 50 transmits a subscriber information request to the subscriber information management device 7 in order to acquire a subscriber class into which the terminal 10 that has transmitted the communication start request is classified. Here, the IMSI or TMSI of the terminal 10 is included in the subscriber information request. The subscriber information management device 7 specifies the subscriber class associated with the identification information of the terminal 10 included in the subscriber information request. The subscriber information management device 7 transmits a subscriber information response including the extracted subscriber class to the server 50 (step S24).

  The extraction unit 54 specifies a combination of a base station, a sector, and a carrier that are used for communication of the terminal 10 for which the policy is requested, from the cell ID included in the policy information request. Further, the requested policy is extracted from the policy information 61 (FIG. 8) using the subscriber class acquired from the subscriber information management device 7. The extraction unit 54 transmits a message (policy information response) notifying the extracted policy to the base station 20 (step S25).

  The acquisition processing unit 31 of the base station 20 acquires a policy information response via the communication unit 24. The acquisition processing unit 31 stores the policy information included in the policy information response in the storage unit 40 as the policy information 41. The notification unit 32 uses the policy information 41 to generate a connection rejection message addressed to the terminal 10.

  FIG. 11 shows an example of the format of the connection rejection message. The connection rejection message includes information indicating connection rejection, information on the terminal 10 whose connection is rejected, and policy information notified to the terminal 10. FIG. 11 shows an example in which RRC CONNECTION REJECT is used as the connection rejection message. When RRC CONNECTION REJECT is used as a connection rejection message, the value of Message Type is used as information indicating connection rejection. As information about the terminal 10, information elements such as RRC transaction identifier and Initial UE identifier in UE information elements are used. Note that TMSI is recorded as Initial UE identifier. “Rejection case” is information regarding the cause of refusal of connection, and “Wait time” is the length of time that the terminal 10 waits for retransmission of the communication start request.

  The policy information notified to the terminal 10 is included in the redirection info. Redirection info includes Frequency into and inter-RAT into. Frequency into is information on the frequency used for communication of the terminal 10. In the example of FIG. 11, inter-RAT info includes WiFi AP info, 3GPP2 info, and WiMax info.

  The notification unit 32 records the information of the access point 70 in the non-cellular network 15 among the policy information received from the server 50 and the priority order for the access point 70 in the WiFi AP info. For example, as shown in FIG. 10, when the priority applied to the terminal 10 is in the order of the access point 70b, the access point 70a, and the cellular network 1 (base station 20), the notification unit 32 sends the access point 70b to the access point 70b. It records in WiFi AP info that the connection priority is first and the connection priority to the access point 70a is second. Further, the notification unit 32 records in 3GPP2 info that the priority of connection to the base station 20 is third. The notification unit 32 transmits the generated connection rejection message to the terminal 10 via the transmission unit 22 (step S26 in FIG. 10).

  Using the connection rejection message, the terminal 10 recognizes that the priority order of connection destinations is the order of the access point 70b, the access point 70a, and the base station 20 (cellular network 1), and the connection destination list 11a (FIG. 7). Is updated to the connection destination list 11b. Since the terminal 10 is requested to give the highest priority to the access point 70b as a connection destination in the connection destination list 11b, the terminal 10 requests connection to the access point 70b.

  As shown in step S27, processing for connecting the terminal 10 to the WiFi network is performed as connection processing for communication via the access point 70b. That is, an authentication request from the terminal 10 to the access point 70b and an authentication process at the access point 70b, and an authentication request and an authentication process from the access point 70b to the terminal 10 are performed. Thereafter, the terminal 10 requests connection to the access point 70b (Association request), and a response (Association response) from the access point 70b is transmitted to the terminal 10. Thereafter, communication is performed between the terminal 10 and the access point 70b (step S28).

  FIG. 12 is a flowchart for explaining an example of reception processing of a communication start request during access restriction. Note that FIG. 12 is an example, and for example, changes such as changing the order of steps S33 and S34 can be performed. When the base station 20 receives a communication start request from the terminal 10, the determination unit 33 extracts information on access restriction and determines whether the access restriction is targeted (steps S31 and S32). If the terminal 10 that has transmitted the communication start request is subject to access restriction, the acquisition processing unit 31 extracts the cell ID and the IMSI or TMSI from the communication start request (Yes in Step S32, Steps S33 and S34). The acquisition processing unit 31 generates a policy information request including the cell ID and the IMSI or TMSI, and transmits it to the server 50 (step S35). On the other hand, when the terminal 10 that has transmitted the communication start request is not subject to access restriction, the connection processing unit 34 performs a connection process between the terminal 10 and the base station 20 (No in step S32, step S36).

  FIG. 13 is a flowchart illustrating an example of the operation of the server 50 requested for policy information. The extraction unit 54 in the server 50 acquires the subscriber class associated with the IMSI or TMSI for which the policy information is requested from the subscriber information management device 7 (step S41). The extraction unit 54 extracts policy information to be applied to the terminal 10 using information in the subscriber class and the cell ID (step S42). When extracting the policy information to be applied to the terminal 10, the extraction unit 54 transmits a policy information response including the policy information to the base station 20 via the transmission unit 52 (Yes in step S43, step S45). On the other hand, when the policy information to be applied to the terminal 10 cannot be extracted, the extracting unit 54 transmits a policy information response indicating that the user of the terminal 10 has not subscribed to the service to the base station 20 (step S43). No, steps S44, S45).

  FIG. 14 is a flowchart illustrating an example of connection rejection message transmission processing. The notification unit 32 of the base station 20 determines whether the policy information notified from the server 50 is other than information indicating that the user of the terminal 10 has not subscribed to the service (step S51). Note that the notification unit 32 may perform the process of step S51 using a policy information response, or may refer to the policy information 41. When the server 50 notifies the user of the terminal 10 that the service has not been subscribed, the notification unit 32 ends the process (No in step S51). When the policy information applied to the terminal 10 is notified from the server 50, the notification unit 32 determines whether the cellular network 1 is designated as the highest priority network based on the policy information (step S52). When the cellular network 1 is set as the highest priority network, the notification unit 32 ends the process (No in step S52).

  On the other hand, when a network other than the cellular network 1 is set as the highest priority network, information related to the network notified as the connection destination is recorded in the connection rejection message (setting loop shown in steps S53 to S55). The notification unit 32 repeats setting of connection destination information for all information included in the policy information applied to the terminal 10 until the setting process for the connection rejection message is completed. Thereafter, the notification unit 32 transmits a connection rejection message to the terminal 10 via the transmission unit 22 (step S56).

  FIG. 15 is a flowchart illustrating an example of processing performed by the terminal 10 that has been refused connection. The terminal 10 extracts the information notified as the connection destination by the connection rejection message, and updates the connection destination list 11 using the extracted information (update loop shown in steps S61 to S64). The terminal 10 repeats the extraction of information from the connection rejection message and the update of the connection destination list 11 until all the information included in the connection rejection message is used for the update process of the connection destination list 11. Thereafter, the terminal 10 issues a connection request to a connection destination having a high priority in the connection destination list 11.

  As described above, in the first embodiment, the base station 20 notifies the policy information applied to the terminal 10 when rejecting establishment of communication with the terminal 10. For this reason, the terminal 10 can change the priority of the connection destination according to the policy information notified by the connection rejection message. In other words, if communication with the base station 20 fails once, the terminal 10 can request connection to the access point 70 of the network with good communication without retrying establishment of communication with the base station 20. . Therefore, according to the first embodiment, the terminal 10 can connect to a network having a good communication state in a short time.

  FIG. 16 is a sequence diagram illustrating an example of a processing delay that can be avoided according to the first embodiment. The base station 8 is assumed to be a base station that does not support the first embodiment. When the terminal 10 transmits a communication start request to the base station 8 under the situation where the first embodiment is not used, as shown in FIG. 16, the connection request from the terminal 10 is subject to access control as the base station 8. (F1, f2). In this case, since the terminal 10 does not receive a response even after a predetermined time has elapsed after transmitting the communication start request to the base station 8, the terminal 10 transmits the communication start request to the base station 8 in order to retry the connection. (F3). However, the base station 8 discards the communication start request in the same manner as f2, and does not respond to the terminal 10. As a result, the terminal 10 periodically repeats transmission of the communication start request until the predetermined number of retries is reached (f5). On the other hand, since the access restriction is also generated in the base station 20, the communication start request from the terminal 10 is continuously discarded (f6). After attempting to connect to the terminal 10 until the predetermined number of retries is reached, the terminal 10 tries to connect to the second priority network without updating the connection destination list 11a. Here, since the access point 70b is selected as the connection destination, the processing performed at f7 and f8 is the same as steps S27 and S28 described with reference to FIG.

  If the first embodiment is used, the connection retry shown in f3 to f6 shown in FIG. 16 has not been performed. That is, if the first embodiment is not used, since the terminal 10 does not change the connection destination while performing the retry, the connection of the terminal 10 is delayed for the period indicated by T in FIG. become. The period indicated by T in FIG. 16 is represented by the product of the retry period and the number of retries. For this reason, for example, if the number of retries is 4 and the retry period is 4 seconds, the terminal 10 has a connection delay of 16 seconds. Furthermore, since access restriction has occurred, the base station 8 repeatedly receives a communication start request from the terminal 10 even though the load on the base station 8 is high. The load on the vehicle is also heavier than when using the first embodiment.

  On the other hand, according to the first embodiment, when the terminal 10 recognizes that the connection to the base station 20 has failed, the connection destination list 11 is changed to avoid retry of reconnection to the base station 20 and to perform communication. Connect to a good network early. Further, according to the first embodiment, the load on the cellular network 1 due to the connection retry from the terminal 10 is also reduced.

<Second Embodiment>
In the second embodiment, an example in which a failure or congestion occurs on the core network side while communication between the terminal 10 and the server 50 is disconnected will be described. In this case, since no congestion or failure has occurred in the base station 20, the base station 20 can establish a connection with the terminal 10, but the terminal 10 is connected to the cellular network 1 due to congestion in the core network. Cannot communicate via. For this reason, when the base station 20 detects congestion or a failure in the core network based on the notification from the server 50, the base station 20 notifies the terminal 10 of a connection destination having a good communication status without establishing a connection with the terminal 10. To do. Then, the terminal 10 can start communication using a network having a good communication state without connecting to the cellular network 1. Details of the processing in the second embodiment will be described below.

  FIG. 17 is a sequence diagram illustrating an example in which the policy information does not match between the terminal 10 and the server 50 due to a failure that occurred during disconnection of communication. Also in the second embodiment, a case where the terminal 10 can connect to any of the base station 20, the access point 70a, and the access point 70b is taken as an example. The processing of steps S71 to S73 is the same as steps S11 to S13 described with reference to FIG. Here, it is assumed that a failure occurs in a device in the core network after the communication between the terminal 10 and the server 50 is disconnected. Then, the maintenance management device 6 transmits a status notification notifying that a failure has occurred in the devices in the core network to the server 50 (step S74). When the update unit 53 of the server 50 acquires the status notification from the maintenance management device 6 via the reception unit 51, the update unit 53 updates the policy information 61. In the following description, it is assumed that the priority order of the connection destination of the terminal 10 is set in the order of the access point 70b, the access point 70a, and the cellular network 1 (base station 20) (policy information 61b). Therefore, as shown in step S75, the information in the connection destination list 11a is different from the information in the policy information 61b.

  FIG. 18 is a sequence diagram illustrating an example of connection processing according to the second embodiment. Steps S73 to S75 in FIG. 18 are as described in FIG. Next, the update unit 53 of the server 50 generates a connection rejection notification request for the base station 20 whose connection priority has been lowered by policy update. As will be described below, the base station 20 notifies the connection rejection message without establishing a connection with the terminal 10 located in the area specified by the connection rejection notification request. Therefore, the server 50 uses a connection rejection notification request as means for notifying the base station 20 of the area where the terminal 10 that refuses connection due to congestion or failure in the core network. The connection rejection notification request is control information that requests the base station 20 to transmit a connection rejection message to a terminal that rejects the connection when the base station 20 rejects the connection. The connection rejection notification request also includes information specifying an area for transmitting a connection rejection message. Also in the second embodiment, as in the first embodiment, the connection rejection message includes information for notifying connection rejection and the policy held by the server 50 for the terminal 10 rejecting the connection. Shall be included. The update unit 53 transmits the generated connection rejection notification request to the base station 20 via the transmission unit 52 (step S81).

  FIG. 19 is a diagram illustrating an example of the determination information 42 according to the second embodiment. The acquisition processing unit 31 of the base station 20 generates the determination information 42 based on the connection rejection notification request transmitted from the server 50. In the table shown in FIG. 19, whether to transmit a connection rejection request to the terminal 10 that is not connected is recorded in units of sectors. In addition, when the server 50 transmits the information on the sector formed by the base station 20 to the base station 20, each base station 20 associates with the identification information on the sector formed by the own device. Record whether to notify the connection rejection message.

  Case C11 in FIG. 18 is an example of processing when the terminal 10 accesses the cellular network 1 via the base station 20, and Case C12 is processing after the terminal 10 changes the connection destination to the non-cellular network 15. It is an example. In the following description, it is assumed that a setting for notifying a connection rejection message is made in all sectors of the base station 20.

  In step S82, since the cellular network 1 (base station 20) is set as the highest priority connection destination in the connection destination list 11a held by the terminal 10, the terminal 10 sends a communication start request to the base station 20. Send. The process of step S82 is the same as step S21 described with reference to FIG.

  In step S83, it is assumed that the determination unit 33 of the base station 20 determines that the connection rejection message is set to be notified to the sector in which the terminal 10 that has transmitted the communication start request is located. In this case, since the connection rejection notification setting = notification is set in the sector where the terminal 10 is located, the determination unit 33 can determine that congestion has occurred in the core network. Further, the determination unit 33 determines that the terminal 10 is a transmission target of the connection rejection message. When the determination unit 33 determines not to establish a connection with the terminal 10, the processes of steps S84 to S88 are performed. Note that the processing of steps S84 to S88 is the same as steps S22 to S26 described with reference to FIG. Therefore, the terminal 10 can receive the policy information applied to the terminal 10 using the connection rejection message without establishing a connection with the base station 20. The terminal 10 updates the connection destination list 11 using the policy information included in the connection rejection message. For this reason, the terminal 10 changes the connection destination according to the connection destination list 11 without establishing a connection with the base station 20 or retrying the connection to the base station 20.

  In the updated connection destination list 11, when the highest priority connection destination is the access point 70b, the terminal 10 requests the access point 70b to connect as shown in case C12. The process performed in case C12 is the same as the process performed in case C2 of FIG. In FIG. 18, the entire WiFi connection process between the terminal 10 and the access point 70 b is indicated by one arrow because of space limitations, but the details of the WiFi connection process are as shown in step S <b> 27 of FIG. 10. It is. Thereafter, the terminal 10 performs WiFi communication via the access point 70b.

  Although the case where the connection rejection notification setting is performed in units of base stations or sectors has been described with reference to FIGS. 18 and 19, the connection rejection notification setting may be performed in units of subscribers. In this case, the server 50 holds a list (notification destination list) of subscribers who wish to receive a connection rejection message when the policy information 61 is changed. When the server 50 holds the notification destination list, every time the policy information 61 is updated, the server 50 includes information for identifying all the subscribers recorded in the notification destination list in the connection rejection notification request. , Notify all base stations 20 in the cellular network 1. Then, the base station 20 associates the notified subscriber information with the notification of the connection rejection message and records it as determination information 42. Further, when receiving the connection start request from the terminal 10, the determination unit 33 of the base station 20 determines whether the identification information of the transmission start request transmission source is recorded in the determination information 42 as a connection rejection message transmission target. When the subscriber who uses the terminal 10 that has transmitted the communication start request is the transmission target of the connection rejection message, the processes of steps S84 to S90 are performed.

  FIG. 20 is a flowchart for explaining an example of the operation of the server 50 according to the second embodiment. When the maintenance management device 6 is notified of the occurrence of a device failure or congestion in the core network, the update unit 53 determines whether to update the policy information 61 based on the notified information (step S101). If the updating unit 53 does not update the policy information 61, the updating unit 53 ends the processing (No in step S101). When updating the policy information 61, the updating unit 53 updates the policy information 61 (Yes in step S101, step S102). The update unit 53 transmits a connection rejection notification request to the base station 20 whose priority has been changed in the policy information 61 (step S103).

  FIG. 21 is a flowchart illustrating an example of a connection rejection notification request reception process. When the base station 20 receives the connection rejection notification request, the acquisition processing unit 31 determines whether or not the determination information 42 is updated by the connection rejection notification request (step S111). If the determination information 42 is not updated, the acquisition processing unit 31 ends the process (No in step S111). The acquisition processing unit 31 determines whether the connection rejection notification request is a notification for each subscriber (step S112). When the connection rejection notification request is made for each subscriber, the acquisition processing unit 31 updates the determination information 42 for each subscriber (Yes in Step S112, Step S113). Next, the acquisition processing unit 31 determines whether the connection rejection notification request is a notification for each base station (step S114). When the connection rejection notification request is made for each base station, the acquisition processing unit 31 updates the determination information 42 for each base station (Yes in step S114, step S115). Furthermore, the acquisition processing unit 31 determines whether the connection rejection notification request is a notification in units of cells (step S116). When the connection rejection notification request is made in cell units, the acquisition processing unit 31 updates the determination information 42 in cell units (Yes in step S116, step S117).

  FIG. 22 is a flowchart for explaining an example of reception processing of a communication start request. In FIG. 22, as in FIG. 18 and FIG. 19, a case will be described as an example where the determination information 42 records whether the connection rejection message is transmitted in units of base stations or sectors.

  When the base station 20 receives the communication start request, the determination unit 33 acquires from the determination information 42 the connection rejection notification setting value associated with the information on the sector where the terminal 10 that is the transmission start request transmission source is located. (Step S121). Using the information acquired from the determination information 42, the determination unit 33 determines whether to transmit a connection rejection message to the terminal 10 that has transmitted the communication start request (step S122). When a connection rejection message is transmitted to the terminal 10 that has transmitted the communication start request (Yes in step S122), the processes in steps S123 to S125 are performed. The processing performed in steps S123 to S125 is the same as the processing in steps S33 to S35 described with reference to FIG. On the other hand, when the connection rejection message is not transmitted to the terminal 10 that has transmitted the communication start request, the base station 20 performs a connection process with the terminal 10 (No in step S122, step S126).

  FIG. 23 is a sequence diagram illustrating an example of a processing delay that can be avoided by the second embodiment. The process shown in FIG. 23 is described as an example of a system in which the base station 8 that is not compatible with the second embodiment is used. In step S126 of FIG. 22, the terminal 10 connects to the base station. The process when established is the same. In the system including the base station 8, when the terminal 10 transmits a communication start request to the base station 8, the terminal 10 establishes communication using the cellular network 1 (f11, f12). At this time, in the communication indicated by f12, the terminal 10 establishes a session with the server 50.

  In f13, the terminal 10 transmits a policy information request including the IMSI assigned to the terminal 10 and the cell ID of the cell in which the terminal 10 is located to the server 50. Then, the server 50 transmits the policy information applied to the terminal 10 to the terminal 10 (f14). The method in which the server 50 notifies the policy information to the terminal 10 in f14 is the same as when the synchronization between the terminal 10 and the server 50 is established. When the terminal 10 updates the connection destination list 11 by receiving the policy information from the server 50, the terminal 10 determines that the access point 70b has the highest priority as the connection destination. After establishing the connection with the access point 70b, the terminal 10 disconnects the connection with the base station 8 (f15).

  If the second embodiment is used, as described with reference to FIG. 18 and the like, connection establishment with the cellular network 1 as shown in f12 to f15 shown in FIG. 23 and communication with the cellular network 1 are performed. No cutting is performed. That is, in FIG. 23, the terminal 10 connects to the cellular network 1 against the policy information 61 of the server 50, so that the terminal 10 establishes communication using the cellular network 1 and then switches to the non-cellular network 15. Connection processing occurs. Such processing further imposes a load on the cellular network 1 in a state where a failure or congestion has already occurred in the core network. Moreover, since transmission / reception of the policy information shown in f13 and f14 performs a user plane setting process, the load on the cellular network 1 is increased.

  On the other hand, when the second embodiment is used, if the base station 20 recognizes that transmission of a connection rejection message to the terminal 10 is requested, the terminal 10 is not connected to the cellular network 1, so that redundant connection is made. Processing is avoided. Furthermore, since the policy information applied to the terminal 10 is notified to the terminal 10 by a connection rejection message, it is possible to avoid a load on the cellular network 1 due to the establishment of a session between the terminal 10 and the server 50.

<Third Embodiment>
In the cellular network 1 shown in FIG. 2, when communication is performed using the NodeB 4 and the radio network controller (RNC) 80, a process for generating a connection rejection message and obtaining a policy applied to the terminal 10 from the server 50 is as follows. Performed by RNC 80. The RNC 80 receives the communication start request from the terminal 10 via the NodeB 4 and transmits a connection rejection message to the terminal 10 via the NodeB 4.

  FIG. 24 is a diagram illustrating an example of the configuration of the radio network control device 80. The wireless network control device 80 includes a communication unit 81, a control unit 82, and a storage unit 85. The control unit 82 includes an acquisition processing unit 31, a notification unit 32, a determination unit 33, and a connection processing unit 83. The storage unit 85 records policy information 41 and determination information 42. The communication unit 81 performs communication processing with the base station, the server 50, and the like. The processing performed by the acquisition processing unit 31, the notification unit 32, and the determination unit 33 included in the RNC 80 is the same as the processing of the acquisition processing unit 31, the notification unit 32, and the determination unit 33 in the base station 20. The connection processing unit 83 performs processing when establishing a connection with the terminal 10. The storage unit 85 holds policy information 41 and determination information 42.

  The hardware configuration of the RNC 80 is the same as that shown in FIG. The communication unit 81 is realized by the network interface 106. The control unit 82 is realized by the processor 101. The storage unit 85 is realized by the RAM 102.

  In this way, the RNC 80 can also generate a connection rejection message and obtain a policy applied to the terminal 10. Therefore, even in a system in which the RNC 80 is used as a connection processing device that performs connection processing between the cellular network 1 and the terminal 10 instead of the base station 20, the same effects as those of the first and second embodiments can be obtained. For example, the terminal 10 can connect to the non-cellular network 15 without retrying the connection with the RNC 80 even in a situation where access control is performed. Further, even when a failure or congestion occurs in the core network, redundant connection processing to the cellular network 1 can be avoided.

<Fourth Embodiment>
FIG. 25 is a diagram illustrating an example of reconnection or communication return processing. The first and second embodiments can also be applied when the terminal 10 performs reconnection or return processing to communication.

  Case C21 shows an example in which the terminal 10 performs reconnection. It is assumed that the terminal 10 is communicating with the opposite apparatus via the cellular network 1 using the route indicated by the arrow A in the communication area formed by the base station 20a. Thereafter, when the terminal 10 moves and enters an area in which radio waves having a strength for communication cannot be received, the communication is disconnected as indicated by an arrow B.

  When the terminal 10 further moves and the terminal 10 enters the communication area formed by the base station 20b, the terminal 10 requests reconnection to the base station 20b. However, the policy information 61 applied to the terminal 10 is changed due to an access restriction, congestion, failure or the like in the cellular network 1 while the terminal 10 is not communicating with either the base station 20a or the base station 20b. There may be. Therefore, in response to a reconnection request from the terminal 10, the base station 20b or the RNC 80 connected to the base station 20b can perform the processing described in the first to third embodiments.

  Cases C22 to C24 describe a case where communication is started again after the terminal 10 ends communication and transitions to a state called Cell_PCH or RRC-Idle. In case C22, the terminal 10 communicates with the opposite apparatus using the connection indicated by the arrow E. As shown in case C22, during communication, connection in the section from the terminal 10 to the device (CN) 110 in the core network via the base station 20 and the RNC 80 is established. In case C23, since there is no traffic between the terminal 10 and the opposite device, the connection (arrow F) between the RNC 80 and the device 110 in the core network is maintained, but the connection between the terminal 10 and the RNC 80 is not maintained. The radio section is released. The state shown in case C23 corresponds to the Cell_PCH state in 3G and the RRC-Idle state in LTE. Next, when the terminal 10 tries to start communication again, the terminal 10 transmits a reconnection request to the RNC 80 (G in case C24).

  Even in cases C22 to C24, the policy information 61 may be changed due to access restriction, congestion, failure, or the like in the cellular network 1 while the terminal 10 is transitioning to the Cell_PCH state or the RRC-Idle state. Accordingly, even in the cases shown in cases 22 to C24, the base station 20b or the RNC 80 connected to the base station 20b performs the processing described in the first to third embodiments in response to the reconnection request from the terminal 10. be able to.

  FIG. 26 is a sequence diagram illustrating an example of processing performed at the time of reconnection. In the example of FIG. 26, the case where the RNC 80 generates a connection rejection message and acquires policy information will be described as an example. However, the base station 20 may perform these processes instead of the RNC 80. Note that a message transmitted by the terminal 10 for a reconnection request or a request for transition to a communication state is also a type of communication start request because it requests the start of communication. Hereinafter, in order to facilitate comparison with other embodiments, a message transmitted by the terminal 10 for a request for reconnection or a request for transition to a communication state is referred to as a “communication start request”.

  As shown in step S <b> 141, when the terminal 10 performs communication using the cellular network 1 through the RNC 80, a session is also formed between the terminal 10 and the server 50. Therefore, communication for synchronizing the connection destination list 11 a held by the terminal 10 and the content of the policy (61 a) applied to the terminal 10 by the server 50 is periodically performed between the terminal 10 and the server 50. (Step S142).

  As shown in step S143, when the terminal 10 can no longer receive the radio wave from the base station 20, the communication between the terminal 10 and the base station 20 is disconnected, thereby causing the communication to be disconnected (step S143). S144). In step S144, since the session between the terminal 10 and the server 50 is also disconnected, the terminal 10 does not communicate with the server 50 after step S144. After that, as shown in step S145, it is assumed that congestion has occurred due to an increase in the number of connections in the base station 20, and the RNC 80 notifies the server 50 of the occurrence of congestion using a network busy notification (step S146). . The server 50 updates the policy information 61 in response to the occurrence of congestion. For this reason, it is assumed that the policy information applied to the terminal 10 is updated from the policy information 61a to the policy information 61b. However, since communication is not performed between the server 50 and the terminal 10, the connection destination list 11a used by the terminal 10 is not updated (step S147).

  In step S148, the terminal 10 transmits a communication start request to the RNC 80 based on the connection destination list 11a in order to resume communication. The communication start request can be an arbitrary control signal for reconnection. For example, RRC CELL UPDATE may be transmitted to RNC 80 via a RACH (random-access channel) as a communication start request. Note that RRC CELL UPDATE also includes IMSI or TMSI. The determination unit 33 of the RNC 80 that has received the communication start request determines whether or not U-plane resources can be allocated to the terminal 10. When the U-plane resource cannot be allocated to the terminal 10, the acquisition processing unit 31 uses the IMSI or TMSI in the communication start request and the cell ID indicating the position of the terminal 10 at the time of transmission of the communication start request. Generate a request. The policy information request is transmitted to the server 50 via the communication unit 81 (step S149).

  The extraction unit 54 of the server 50 obtains the subscriber class applied to the communication start request transmission source from the subscriber information management device 7 in order to obtain the policy information applied to the terminal 10 of the communication start request transmission source. get. The subscriber class acquisition processing (steps S150 and S151) is the same as steps S23 and S24 described with reference to FIG. Thereafter, the extraction unit 54 extracts a policy applied to the terminal 10 using the cell ID and the subscriber class, and generates a policy information response. The policy information is transmitted to the RNC 80 via the transmission unit 52 (step S152).

  The acquisition processing unit 31 of the RNC 80 that has received the policy response stores the policy information included in the policy information response in the storage unit 40 as the policy information 41. The notification unit 32 uses the policy information 41 to generate a connection rejection message addressed to the terminal 10. The connection rejection message may be an arbitrary control signal including the information element of Redirection info described with reference to FIG. For example, CELL UPDATE CONFIRM including the information element of Redirection info may be transmitted to the terminal 10 via the FACH (Forward Access Channel) as a connection rejection message (step S153). Note that it can be said that the RNC 80 notifies the terminal 10 of an instruction to shift to the non-cellular network 15 and policy information applied to the terminal 10 by the information element of Redirection info.

  The terminal 10 updates the connection destination list 11 using the policy information notified by the connection rejection message. In the example of FIG. 26, the connection destination list 11a is updated to the connection destination list 11b. In the connection destination list 11b, since the highest priority connection destination is the access point 70b, the cellular network 1 is not the highest priority network. For this reason, the terminal 10 determines to make a request for releasing a section reserved for communication of the terminal 10 in the cellular network 1.

  In step S154, the terminal 10 transmits a call disconnection request to the RNC 80. Here, the call disconnection request may be transmitted to the RNC 80 via the RACH, for example. It is assumed that the call disconnection request includes information used for releasing the route of the Iu section reserved for communication at the terminal 10.

  In step S155, the connection processing unit 83 of the RNC 80 transmits an IU RELEASE REQUEST of RANAP (Radio Access Network Application Part) to the device 110 in the core network using the call disconnection request. The device 110 in the core network performs processing requested by the received control message, and transmits an IU RELEASE COMMAND to the RNC 80 in response to the IU RELEASE REQUEST (step S156). Then, the RNC 80 transmits RRC CONNECTION RELEASE to the terminal 10 (step S157). Thereafter, the RNC 80 transmits IU RELEASE COMPLETE to the device 110 in the core network (step S158). Through the processing in steps S154 to S158, all areas of the communication path from the terminal 10 to the server 50 are released (step S159).

  The processes in steps S160 to S161 performed after the resources secured before the communication of the terminal 10 is disconnected are the same as those in steps S27 to S28 described with reference to FIG. For this reason, the terminal 10 can resume communication via the access point 70b.

  In the example of FIG. 26, the case where the route of the Iu section is released by the control using the RANAP has been described. However, the release of resources secured in the cellular network 1 for the communication of the terminal 10 is not limited. It may be performed by processing using the protocol.

  Also, when the terminal 10 reconnects as in cases C22 to C24, if the policy information 61 is changed while the terminal 10 is not communicating, the new policy information is updated by the same processing as in FIG. Notification and appropriate network connection processing are performed. In this case, instead of step S143, the communication between the terminal 10 and the server 50 is disconnected due to the absence of traffic between the terminal 10 and the opposite apparatus.

  According to the fourth embodiment, not only when the terminal 10 newly starts communication, but also when communication is resumed, the terminal 10 can be connected to an appropriate network at an early stage. Also, the load on the network is reduced as in the first to third embodiments.

<Others>
The embodiment is not limited to the above, and can be variously modified. Some examples are described below.

  The fourth embodiment can be implemented in combination with the first to third embodiments. Furthermore, the first embodiment and the second embodiment may be combined.

  In the above description, the case where the user is classified into a plurality of subscriber classes according to the contract of the user of the terminal 10 has been described, but the user may not be classified into the subscriber class. In this case, the base station 20 transmits the policy information acquired using the communication start request from the terminal 10a from the area to which the same policy as the terminal 10a is applied within a predetermined period from the acquisition of the policy information. You may notify to the other terminal (10b) which transmitted. If it deform | transforms in this way, since the frequency which accesses the server 50 from the base station 20 becomes low, the burden on the cellular network 1 can further be reduced. The same applies to the RNC 80.

1 cellular network 2 HeNB
3 eNodeB
4 NodeB
6 maintenance management device 7 subscriber information management device 8, 20 base station 10 terminal 11 connection destination list 15 non-cellular network 21, 51 reception unit 22, 52 transmission unit 23 wireless communication processing unit 24 communication unit 30 control unit 31 acquisition processing unit 32 Notification unit 33 Determination unit 34 Connection processing unit 40, 60 Storage unit 41, 61 Policy information 42 Determination information 50 Server 53 Update unit 54 Extraction unit 55 Transmission / reception unit 62 Access restriction information 63 Access point information 70 Access point 80 RNC
101 processor 102 RAM
103 ROM
104 External storage device 105 Bus 106 Network interface 107 Wireless network interface

Claims (7)

A base station used to connect to the first network;
An access point used to connect to the second network;
A communication system comprising a server that determines a priority order of connection destinations for each of the terminals that can connect to the base station and connect to the access point,
When a request to start communication via a first network is received from a target terminal that is a terminal located in a cell formed by the base station, the target terminal is applied to the target terminal when the target terminal is not connected to the first network. Obtaining means for obtaining said priority order from said server;
A communication system comprising: notification means for notifying the target terminal of the priority applied to the target terminal together with connection rejection. A management device for managing a state in the first network;
The server
A receiving unit for receiving a status notification for notifying a status change occurring in the first network from the management device;
Update to update the priority applied to the terminal located in the communication area of the transit base station that is a base station that communicates via the device affected by the state change so that the priority of the transit base station is lowered And
A transmission unit that transmits a notification request for notifying the target terminal of a priority applied to the target terminal when the target terminal is not connected to the transit base station. The communication system according to claim 1. When the notification unit acquires the notification request, the acquisition unit determines that the base station does not connect the target terminal to the first network, and determines a priority applied to the target terminal from the server. The communication system according to claim 2, wherein the communication system is acquired. A management device for managing a state in the first network;
The server
A receiving unit for receiving a status notification for notifying a status change occurring in the first network from the management device;
Update to update the priority applied to the terminal located in the communication area of the transit base station that is a base station that communicates via the device affected by the state change so that the priority of the transit base station is lowered Part,
With
When the base station receives the start request from the target terminal while connection restriction to the base station is being performed, the acquisition unit requests the server to apply the priority applied to the target terminal. The communication system according to claim 1, wherein: The target terminal is
When the priority applied to the target terminal is notified that the second network is prioritized over the first network, the connection retry to the first network is stopped,
The communication system according to claim 1, wherein a process for establishing a connection with the access point is performed. A connection processing device that performs connection processing with a first network,
A receiving unit for receiving a request to start communication via the first network from a terminal capable of connection to the connection processing device and an access point used for communication via the second network; ,
If the connection with the terminal is not established, an acquisition unit that acquires the priority from a server that determines the priority of the connection destination of the terminal;
A connection processing apparatus comprising: a transmission unit that transmits a connection rejection message including the priority and rejection of connection to the terminal to the terminal. In the connection processing device that performs connection processing with the first network,
Receiving a request to start communication via the first network from a terminal capable of connection to the connection processing device and an access point used for communication via the second network;
If the connection with the terminal is not established, the priority is acquired from a server that determines the priority of the connection destination of the terminal,
A communication method characterized by causing the terminal to perform a process of transmitting a connection rejection message including the priority and rejection of connection to the terminal.