JP2013038477A - Policy control method, policy server, and mobile terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a policy control method and a policy server, capable of easily evaluating an actual result of policy control while suppressing the occurrence of a signaling load, and capable of easily adding policy control according to the evaluation result.SOLUTION: A policy request detection unit 100 detects a policy request transmitted from each radio base station B1, B2, accommodating a mobile terminal MN, a security gateway GW or a management node for the radio base stations and the security gateway, in response to a predetermined event. To mitigate congestion in the radio base station B1, B2, a policy control unit 101 generates a policy applied to each mobile terminal MN subordinate to each base station. A policy transmission unit 102 transmits the generated policy to each subordinate mobile terminal MN, through the radio base station transmitting the policy request.

Description

  The present invention relates to a policy control method, a policy server thereof, and a mobile terminal, and in particular, applies a policy control to a mobile terminal having a plurality of radio interfaces, and each mobile terminal uses a radio interface used for connection to a core network. The present invention relates to a policy control method to be controlled, a policy server thereof, and a mobile terminal.

  In recent years, mobile terminals equipped with other access methods such as Wi-Fi in addition to an access method for cellular communication have become widespread. In such a mobile terminal, as a method of controlling the use of each access method according to the situation, when the cellular base station is congested, it is possible to reduce congestion by switching to Wi-Fi access, or Use communication and Wi-Fi at the same time, use cellular communication with easy quality assurance for communications that require high QoS, such as VoIP, and use Wi-Fi for other communications It is possible.

  Patent Document 1 presents a control method for preventing a large number of mobile terminals from simultaneously switching from one radio system with a high degree of congestion to the other radio system and minimizing the number of mobile terminals to which the radio system is switched. ing. Here, the mobile terminal acquires the degree of congestion composed of the actual communication amount with respect to the allowable communication amount in each wireless module station. Then, the mobile terminal calculates an index value including the degree of congestion of the radio module station in use with respect to the degree of congestion of the unused radio module station. Next, the mobile terminal calculates a back-off time according to the magnitude of the index value. Then, the mobile terminal waits for the back-off time when the communication quality of the wireless module station being used falls below a predetermined threshold. Thereafter, when the communication quality in the wireless module station in use is again below a predetermined threshold, the mobile terminal transmits a switching request from the wireless module station in use. As a result, the mobile terminal can realize wireless switching according to the degree of congestion.

  Non-Patent Document 1 defines interwork and architecture for connection using an access method called LTE defined by 3GPP and connection using an access method other than 3GPP. Each access method has a function to provide data communication to mobile terminals by using a GW with a home agent function called an anchor GW as a node for both access via the access GW for that access method. Has been.

In addition, when there are a plurality of access methods, a node having a function for discovering and selecting an access NW for performing access method discovery and selection is also defined. This access NW discovery / selection node holds information for access NW discovery, such as information on identifiers such as SSID in the case of a wireless LAN, as well as information on access NW selection such as which access NW is preferred. This can be provided to the mobile terminal. The mobile terminal to which the information is provided executes switching of access methods, traffic movement between access methods, and the like based on the information.
Non-Patent Document 2 defines a function of broadcasting to a mobile terminal connected to an LTE base station when LTE is used as the access NW. Broadcast transmits a broadcast message to a mobile terminal connected to a target base station based on an identifier that uniquely identifies the base station.

  Non-Patent Document 3 discloses a technique for acquiring and providing the location of a mobile terminal to a communication server when the communication session of the mobile terminal is established using IMS. Here, the location of the mobile terminal may be represented by the location of the base station, and the network specifies the location for each user and provides it to the communication server.

JP 2010-147906 A

3GPP TS 23.402 3GPP TS 23.401 3GPP TR 23.842

  Since the radio frequency is finite, when a mobile terminal has a plurality of radio access schemes, if the base station connected to one radio access scheme IFa is congested, the operator of the network is connected to this base station. All traffic is switched from one radio access method IFa to another radio access method IFb, or a part of the traffic is left in one radio access method IFa while the rest is other one There may be a case where it is desired to move to the wireless access method IFb.

  As a countermeasure for such a case, it can be expected that the terminal user voluntarily performs access switching and traffic distribution. However, in order for the operator to stably operate the infrastructure such as the base station, the operator policy It is necessary to be able to manage and control access switching and traffic distribution along the lines. As an implementation method, it is conceivable that an operator uses a policy server that manages and controls a policy relating to access switching and traffic distribution of user terminals.

  At this time, the policy server needs to transmit the policy only to the mobile terminal accommodated in the base station of the radio access scheme IFa, and accurately grasp the mobile terminal that has controlled the radio access scheme in accordance with the transmitted policy.

  In Patent Document 1, a mobile terminal acquires congestion information of a base station and switches a radio access method based on the congestion information. However, when the two wireless access methods are operated by different operators, for example, if one wireless access method is LTE and the other wireless access method is a public wireless LAN, It is difficult to determine whether or not the connection is from a mobile terminal that is under the LTE base station.

  There is also a method for confirming the correspondence with the base station based on position information such as GPS. However, if the position information includes an error, it is difficult to specify. In addition, when the mobile terminal transmits incorrect location information when connecting, policy control for the mobile terminal cannot be performed accurately.

  As in Non-Patent Document 2, in policy control, it is possible to link each access by managing a plurality of connections via wireless access by one policy server. However, if the policy control associated with the base station is to be realized, for example, when the session information is transmitted to the policy server in connection via LTE, it is also necessary to send the base station information together. In this case, if the policy is not changed, new signaling is unnecessary, but the policy server needs to acquire the base station information every time the base station changes, and redundant signaling occurs.

  Although it is conceivable to use a method of acquiring location information only when it is necessary from the policy server as in Non-Patent Document 3, for each user belonging to the base station, the location information is acquired for each session. Since it needs to be acquired, when a large number of users are connected to the base station, the signaling load becomes large.

  The object of the present invention is to solve the above-described problems of the prior art, and to easily evaluate the results of policy control while suppressing the occurrence of signaling load, and further to easily add policy control according to the evaluation result A method and its policy server and mobile terminal are provided.

  In order to achieve the above object, the present invention provides a policy control method in which policy control is applied to a mobile terminal having a plurality of radio interfaces, and each mobile terminal controls a radio interface used for connection to a core network. It is characterized by the following measures.

  (1) A first policy request is transmitted to the policy server in response to congestion of a radio base station connected to one radio access method IFa of the mobile terminal, and the policy server responds to the first policy request, A base station unit policy session and a first policy for managing a policy of each mobile terminal located under the radio base station are created and associated with the first key.

  (2) The policy server broadcasts the first policy and the first key to the subordinate mobile terminal via the radio base station, and the mobile terminal that has received the first policy transmits the contents of the first policy. Determine and execute a signaling process for switching the access method to the core network.

  (3) As a signaling process after judging the contents of the policy, one wireless access method is disconnected and a connection process to the core network is performed using another wireless access method. While leaving some traffic, the remaining traffic is transferred to another radio access scheme, or if the radio access scheme is already used according to the policy, the control state is signaled.

  (4) During signaling processing to the core network, in addition to the terminal identifier, the gateway accesses the core network using the first key as authentication information, and the gateway authenticates the mobile terminal with the terminal identifier and the first key. The above processing is performed, and then the terminal identifier and the first key are transmitted to the policy server.

  (5) The policy server finds a base station unit policy session based on the first key, and registers the terminal identifier and the first key in association with each other as information of the base station unit policy session.

  (6) The policy server creates a terminal unit policy session based on the terminal identifier, or updates the terminal unit policy session information if the terminal already has a terminal unit policy session. Station unit policy session information and the first key are registered together as terminal unit policy session information.

  (7) The policy server then sends a further second policy request from the base station to the policy server and evaluates based on the status of the base station unit policy session and terminal unit policy session managed and controlled by the policy server Triggered by generating a new second policy and a corresponding second key in the base station unit policy session, the processes (2) to (5) are performed, and the second key To find a base station unit policy session, and register and associate a terminal identifier and a second key as information of the base station unit policy session, thereby grasping the difference between the result of the first policy and the result of the second policy. Then, control such as policy creation is performed.

  According to the present invention, the policy server does not need to manage in advance which base station the terminal is in. Also, the mobile terminal that has performed the signaling process according to the policy transmitted from the policy server can be grasped and managed on the policy server side together with the base station information. As a result, it can be reflected in further policy control. In addition, since a series of processes can be repeatedly understood as the contents of policy control for the same base station unit, control such as further policy control based on the reflection result for each policy becomes easy. In addition to policy control, for example, mobile terminals that comply with the policy can be given preferential treatment in terms of fees and services.

1 is a block diagram showing a configuration of a wireless network to which the present invention is applied. It is a functional block diagram of the policy server which concerns on 1st Embodiment of this invention. It is a functional block diagram of a mobile terminal to which the present invention is applied. It is a sequence flow of the policy control method which concerns on 1st Embodiment of this invention. It is the figure which showed the registration content (the 1) of a base station unit policy session. It is the figure which showed the registration content (the 2) of a base station unit policy session. It is the figure which showed the registration content (the 1) of a terminal unit policy session. It is a functional block diagram of the policy server which concerns on 2nd Embodiment of this invention. It is a sequence flow of the policy control method which concerns on 2nd Embodiment of this invention. It is the figure which showed the registration content (the 3) of a base station unit policy session. It is the figure which showed the registration content (the 4) of a base station unit policy session. It is the figure which showed the registration content (the 2) of a terminal unit policy session.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a main part of a radio network to which the present invention is applied, and each mobile terminal MN includes a plurality of radio interfaces. In this embodiment, each mobile terminal is equipped with an LTE interface IF1 and a wireless LAN interface IF2 for cellular communication defined by 3GPP, and the LTE interface IF1 is connected to the gateway GW1 of the core network via the cellular base station B1. The The cellular communication interface IF1 is not limited to LTE, and may be a radio access scheme such as CDMA2000 EV-DO.

  The wireless LAN interface IF2 is connected to the gateway GW2 of the core network through the wireless LAN base station (access point) B2. Connected to the core network is a policy server Ps that generates and manages a policy for switching the interface that each mobile terminal MN connects to the core network and distributing traffic for each interface. Furthermore, the policy server Ps includes a reference point for exchanging information on mobile terminals connected to each GW.

[Example 1]
FIG. 2 is a functional block diagram showing the configuration of the main part of the policy server Ps according to the first embodiment of the present invention, and illustrations of components unnecessary for the description of the present invention are omitted.

  The policy request detection unit 100 detects a policy request transmitted in response to a predetermined event by the radio base stations B1 and B2, the gateways GW1 and GW2 that accommodate the mobile terminal MN, or their management nodes (not shown). In the present embodiment, when it is determined that the degree of congestion of each of the radio base stations B1 and B2 has exceeded a predetermined threshold, a policy request for realizing the congestion reduction of the radio base station is triggered by this. An example of the case of being transmitted to will be described.

  In response to the policy request, the policy control unit 101 generates a policy applied to each mobile terminal MN located within the communication area of the radio base station in order to reduce congestion of the radio base stations B1 and B2. The policy transmission unit 102 transmits the generated policy to each mobile terminal MN under its control via the radio base station that transmitted the policy request.

  In the policy control unit 101, the policy session management unit 103 generates and manages a policy session in units of base stations in response to the policy request. Hereinafter, a policy session generated and managed in units of base stations is expressed as a “base station unit policy session”.

  The base station unit policy session is a policy session (management information) that is applied to each mobile terminal under the base station related to the session and controls an access method, a charging method, and the like. Base station ID).

  In the base station unit policy session, as will be described later, management of a terminal identifier of a mobile terminal located within the communication range of the associated radio base station is also performed, but at the time of receiving the policy request, the policy server Ps does not need to know individual information such as identifiers and location information of the mobile terminals MN. Therefore, in the present invention, the policy server Ps does not always have to know which radio base station the mobile terminal MN is located in.

  In response to the policy request, the policy generation unit 104 generates a policy for switching each radio terminal connected to the core network for each mobile terminal MN located within the radio base station.

  FIG. 3 is a functional block diagram showing the configuration of the main part of the mobile terminal MN. Here, the configuration unnecessary for the description of the present invention is also omitted.

  The policy receiving unit 202 receives the policy transmitted from the policy server Ps via the LTE interface IF1 or the wireless LAN interface IF2. The information storage unit 201 stores communication conditions desired by the user (user communication conditions), network conditions around the terminal, and the like. The signaling process determination unit 202 collates the content of the received policy with each piece of information stored in the information storage unit 201, and determines the signaling process to be executed by the own terminal. The signaling procedure execution unit 203 executes the determined signaling procedure.

  It should be noted that when the user communication conditions such as “Always give priority to LTE” and “Leave some traffic in LTE” are registered, it may not follow the policies that do not match these communication conditions. It is determined by the signaling processing determination unit 203. In addition, when a plurality of policies are designated, the signaling process determining unit 202 also determines that only the signaling process that matches the user communication condition or the like is performed.

  Next, the operation of the present embodiment will be described in detail along the sequence flow of FIG. When a congestion state is detected in cellular base station B1 wirelessly connected to one interface of mobile terminal MN (here, LTE interface IF1 for cellular communication) at time t1, at time t2, the cellular base station B1 A policy request for reducing congestion is sent from to the policy server Sp. This policy request includes the base station ID for uniquely identifying the cellular base station B1, the number n of mobile terminals MN connected to the cellular base station B1, and the traffic load factor L of the cellular base station B1. Etc. can be included.

  Such policy request notification includes direct notification from the cellular base station B1 to the policy server Ps, notification from the cellular base station B1 via the GW accommodating communication via the base station, and control of the cellular base station B1. Notification via a node that manages signaling or notification via a node that manages and manages the cellular base station B1 is possible.

  As for the congested state, the maximum number of terminals that can be accommodated by the cellular base station B1 when the use band exceeds a threshold corresponding to, for example, 90% of the maximum communication band that can be provided by the cellular base station B1. When the threshold value corresponding to 80% of the number is exceeded, or the number of accommodated sessions exceeds the threshold value equivalent to 70% of the maximum number of communication sessions that can be accommodated by the cellular base station B1, for example, It can be judged.

  At time t3, the policy request is detected by the policy request detection unit 100 of the policy server Sp, and the policy session management unit 103 creates a base station unit policy session identified by the base station ID. At this time, key information K1 for the base station unit policy session is created and linked to the base station unit policy session, and each mobile terminal MN subordinate to the cellular base station B1 is used in the policy generation unit 104. Policy P1 to be applied to is also created.

  The policy P1 includes (1) handover in which the mobile terminal MN that has received the policy switches the connection method to the core network from one radio access method to another radio access method, and (2) radio access to the core network An IP that allows simultaneous access by multiple wireless access methods by adding a method, some traffic is connected by one existing wireless access method, and the remaining traffic is moved to another added wireless access method For example, Flow Mobility.

  In addition, when a wireless access method capable of communicating without connection to a core network such as a wireless LAN is provided, (3) control to disconnect all connections to the core network and connect directly to the Internet from the wireless LAN is possible. In addition, when it is specified that the connection to the core network is disconnected as a policy, (4) a detach process for disconnecting the current connection is also possible. Here, the description will be continued on the assumption that the policy P1 that prompts the terminal user to switch from the LTE interface to the wireless LAN interface has been created.

  FIG. 5 shows an example of a base station unit policy session created at time t3. With the base station ID [40297] as an index, a policy P1 “switch from LTE to WiFi” and key information K1 [378671] It is registered. However, the information column of the terminal unit policy session described later is blank.

  The policy P1 may be a static policy created in advance for reducing congestion of the radio base station, or the number of connections n of mobile terminals MN and base stations notified from the cellular base station B1 at time t2 The policy may be dynamically created based on the traffic load factor L of the station B1.

  Further, the policy that can be specified is not limited to one, and a plurality of policies may be specified together with the priority. For example, the priority 1 policy specifies direct access from the wireless LAN to the Internet, and the priority 2 policy specifies the wireless LAN as the connection method via the core network, and the user registers in advance the conditions he / she wants to communicate with. In addition, the highest priority policy that matches this can be adopted.

  At time t4, a broadcast request in which the determined policy P1, key information K1, and base station ID are described is transmitted from the policy transmission unit 102 of the policy server Sp to the cellular base station B1. The requested cellular base station B1 is identified by the base station ID. At time t5, the policy P1 and the key information K1 are distributed by broadcast from the cellular base station B1 that has received the broadcast request to the subordinate mobile terminal MN.

  In this broadcast, it is only necessary to be able to send a message to mobile terminals MN located within the base station unit, for example, Cell Broadcast Service (CBS) in LTE, Broadcast and Multicast Services (BCMCS) in CDMA2000 EV-DO, etc. Can be used. In addition, by using 802.11u or the like in the wireless LAN, it is possible to broadcast to mobile terminals MN in the area.

  Such a broadcast may be performed by the policy server Ps itself, or a separate broadcast dedicated node may be prepared and the policy server Ps may be implemented via the dedicated node. For example, in LTE, broadcasting may be performed via Access Network Discovery and Selection Functions (ANDSF).

  Further, depending on the mobile terminal MN, an idle state in which only a broadcast signal from the base station can be received even when a radio access link is not established is defined. The policy P1 can be received even when not being used.

  Such a mobile terminal MN does not actually use radio access and does not contribute to the congestion of the radio base station, but a new communication is generated before the congestion state of the radio base station is resolved. Even in such a mobile terminal, it is possible to expect the effect of preventing the deterioration of the congestion state in advance by distributing the policy in the same manner.

  Referring to FIG. 3, the policy P1 is received by the policy receiving unit 200 of each mobile terminal MN, and the content thereof is determined. In addition, in order to prevent all mobile terminals MN that have received the policy P1 from being broadcast, the mobile terminal MN that has received the policy P1 has its own terminal ID that satisfies a predetermined condition (for example, If only the terminal ID is even or odd) and the policy P1 is accepted, it can be expected that the terminal executing the policy P1 is limited to only a part of the terminals.

  The signaling processing determination unit 202 includes the contents of the policy, user communication conditions and network conditions previously set and stored in the information storage unit 201 (in this case, whether or not there is a wireless LAN access point around) In consideration of the above, the actual signaling process to be performed is determined, and the determination result is transmitted to the signaling process execution unit 203.

  The signaling processing execution unit 203 executes signaling processing for connection to the core network according to the notified processing content at time t6. In the present embodiment, the access method to the core network is switched from the LTE interface IF1 to the wireless LAN interface IF2.

  Note that some mobile terminals MN may already use the access method specified in the policy. In this case, the current connection update process is executed as a signaling process to the core network. .

  When the mobile terminal MN performs a signaling process to the core network according to the policy P1, the user ID for identifying the mobile terminal MN and the key information K1 distributed together with the policy are one of authentication information for connection. Used as one. In addition, when the policy P1 does not match the user communication conditions or the control is different from the policy P1 because the wireless LAN does not exist in the vicinity as the network status, the reason is also notified. .

  In the signaling process for executing the connection via the wireless LAN, the connection to the core network is made from the access point B2 via the security gateway GW in order to ensure security and authentication. For this connection, the key information K1 is used as one piece of authentication information, and the plurality of mobile terminals NM all use the same key information K1. Such key information can be notified by being installed in Vendor ID Payload using a protocol such as IKEv2. At the time of connection, the user ID is also transmitted from each mobile terminal MN.

  As another example of connection, in signaling processing via LTE, IMSI or related ID may be used as a user ID, and key information may be transmitted as one of protocol information called Protocol Configuration Options. it can.

  At time t7, creation of a policy session for a mobile terminal connected to the policy server Sp from the gateway GW via the access point B2 from the wireless LAN interface (hereinafter referred to as a terminal unit policy session) is requested. At this time, the key information K1 and user ID sent from the mobile terminal MN are used as information for specifying a session.

  Unlike the base station unit policy session, the terminal unit policy session is information for managing and controlling a session (management information) on a terminal basis, and is uniquely specified by a user ID.

  When the policy server Sp finds that the key information K1 is included in the request for creating the terminal unit policy session, the policy server Sp searches for the presence of the base station unit policy session in which the key information K1 is registered. When a session is found, the base station unit policy session information is updated, and the terminal unit policy session is searched by the user ID to create, modify or update the terminal unit policy session.

  FIG. 6 shows the registration contents of the updated base station unit policy session. In the illustrated example, the mobile terminal MN with user IDs [8365678] and [2768678] accepts the policy P1 and performs signaling processing. And the network access method has been switched from LTE to WiFi. On the other hand, in the mobile terminal MN with the user ID [632434], the policy P1 is not accepted because there is no wireless base station for WiFi in the vicinity, and the access method to the network remains LTE. is there.

  On the other hand, when creating, modifying, or updating a terminal unit policy session, the policy server Ps registers a user ID and a policy result in association with the policy P1 and the key information K1 as information of the terminal unit policy session. When the request is notified from the GW, the reason for performing the process different from the policy is also registered.

  FIG. 7 is a diagram showing an example of the terminal unit policy session. Information on the base station unit policy session is managed for each user ID and connection destination GW.

  For example, in the terminal unit policy session related to the mobile terminal having the user ID [2768678], in addition to the user ID, GW1 is registered in the connection destination GW column as information specific to the terminal unit policy session. In addition, as base station unit policy session information, the base station ID is [40297], the policy is “LTE to WiFi”, the key information is [378671], and the policy result is “LTE to WiFi”. Has been.

  Note that some information overlaps between the base station unit policy session and the terminal unit policy session, so the one policy session is not equipped with the duplicate information and is stored in a form that refers to the other policy session. can do. Further, a plurality of policy servers Ps may be configured so that information is distributed and held. In that case, a base station unit policy server may be registered in one policy server, and a terminal unit policy session may be registered in another one policy server. By performing this registration process, the policy server Ps can grasp the number n of mobile terminals that have accepted the policy P1 transmitted at time t4 and switched the connection.

  In addition, it is assumed that the mobile terminal MN has already created a terminal unit policy session before the start of the sequence shown in FIG. 4, but in this case, the already created terminal unit policy session is identified by the user ID. The process is executed in such a manner that information managed in the session is partially corrected and updated.

  According to this embodiment, when a radio base station is congested, a policy effective for mitigating congestion of the radio base station is transmitted to the multi-access mobile terminal MN located under the radio base station, and policy control for mitigating congestion is performed. Therefore, the congestion of the radio base station can be reduced. Further, when the mobile terminal according to the policy accesses through the wireless interface after switching, the policy server Sp can recognize the mobile terminal according to the policy.

  Furthermore, according to the present embodiment, the policy server does not always manage the location information of the mobile terminal, and recognizes the mobile terminal located within a certain base station triggered by congestion of the base station, etc. It is possible to grasp the policy distribution along with the control result of the policy. Therefore, the operator can perform further policy control and distinguish users by processing such as billing, etc., and efficiently perform congestion reduction of the base station according to the operator's policy and under the operator's control it can.

[Example 2]
FIG. 8 is a functional block diagram showing the configuration of the main part of the policy server Ps according to the second embodiment of the present invention. The same reference numerals as those in FIG. Omitted. In this embodiment, a policy evaluation unit 105 and a second policy generation unit 106 are added to the policy control unit 101.

  As will be described in detail later, the policy evaluation unit 105 identifies, for example, the mobile terminal MN that has accessed using the key information K1 in the radio interface F2 after switching, and the first policy associated with the key information K1. The result of the first policy is evaluated based on P1 and the number of mobile terminals n accessed through the switched wireless interface. When the result of the first policy P1 falls below a predetermined reference value, the second policy generation unit 106 generates the second policy P2 that complements the result of the first policy P1. Based on the result, a second policy that the mobile terminal MN wants to further execute is generated.

  Next, the operation of the present embodiment will be described in detail along the sequence flow of FIG. Note that the processing from time t1 to time t7 is the same as or equivalent to that in the first embodiment, and a description thereof will be omitted.

  At time t7, when it is requested to create a policy session for the mobile terminal MN connected via the access point B2 from the wireless LAN interface to the policy server Sp from the gateway GW, the policy server Sp transmits at time t4. Since it is possible to grasp the number n of mobile terminals that have accepted the policy P1 and switched connections, additional policy control based on this can be performed.

  At time t8, the policy server Sp creates a new policy in relation to the base station unit policy session created at the time t3 for the cellular base station B1 based on the key information K1. As a result, it is possible to perform policy control that identifies the mobile terminal MN connected to the core network under the cellular base station B1 and via wireless access other than the LTE interface.

  At time t9, in the base station unit policy session for the cellular base station B1, the second policy P2 and key information K2 associated with the policy P2 are newly created using the evaluation result of the first policy P1 as feedback.

  For example, at time t3, it is recognized that 100 mobile terminals MN are connected to the cellular base station B1, and 50% of them expect 50 mobile terminals MN to switch access methods. Suppose that the first policy P1 that switches the access method is distributed. However, when there are 40 mobile terminals MN subsequently connected via the wireless LAN interface using the key information K1, the policy evaluation unit 105 shows that the effect of policy control is lower than expected. The reason for this is that, for example, some mobile terminals MN are already out of the range of the access point B2 and cannot accept the policy, or the switching of the access method is permitted by the will of the terminal user. Etc.

  As described above, when the first policy P1 that is expected to be accepted by 50% of the mobile terminals MN is actually accepted only by 40 mobile terminals MN (80% of the expected value), The second policy P2 is created by the second policy generation unit 106 with the content of switching the connection with a probability of 50/80 = 62.5% so as to be accepted by 50% of the mobile terminals MN.

  As a trigger for this processing, there are a method of starting a timer at time t8 and starting it when the timer expires, or a method starting at a timing when a certain mobile terminal MN is connected with the key information K1 at time t8. It is done.

  FIG. 10 shows the registration contents of the base station unit policy session at this time, and a new policy P2 “switch from LTE to WiFi” and key information K2 [882312] are added to the base station unit policy session created at time t3. ] Is registered. However, the terminal unit policy session for the newly created policy P2 has not been registered yet.

  At time t10, the policy server Ps delivers the broadcast request describing the policy P2, key information K2, and base station ID to the cellular base station B1 to the cellular base station B1. At this time, it is possible to distribute information to the mobile terminal MN in an idle state in which a connection is not established but a broadcast signal can be received by broadcasting.

  At time t11, the cellular base station B1 broadcasts the policy P2 and the key information K2 to the subordinate mobile terminal MN in response to the request from the policy server Ps. At time t12, the mobile terminal MN that has received the broadcast distribution determines the signaling process for the policy P2 in the same manner as described above, and executes the signaling process for the core network. At that time, its own user ID and key information K2 are used as authentication information.

  At time t13, the gateway GW2 of the core network requests creation of a policy session related to the mobile terminal MN connected via the access point B2. At this time, for a mobile terminal that has already established a policy session, it requests the policy server Ps to update or modify the information. At that time, the key information K2 and the user ID sent from the mobile terminal MN are used as information for specifying a session.

  For example, at the time t5, the policy session is newly created for the mobile terminal NM2 that is not located under the cellular base station B1 and is connected to the cellular base station B1. On the other hand, for a mobile terminal MN that is located under the cellular base station B1 at time t5 and for which a policy has already been created, the policy session is corrected.

  At time t14, the policy server Ps creates or modifies the terminal unit policy session for the mobile terminal MN in association with the base station unit policy session for the cellular base station B1 created at the time t3 based on the key information K2. Is done.

  FIG. 11 shows the registration contents of the base station unit policy session at the time point. The result of the signaling process performed by the mobile terminal and the information of the terminal unit policy session are registered in association with the newly created policy P2 and key information K2. In this example, a mobile terminal that has already complied with policy P1 receives policy P2 and performs signaling processing. Furthermore, the result of the signaling process performed by the mobile terminal with the user ID [5234789] newly receiving policy P2 is registered.

  FIG. 12 shows the state of the terminal unit policy session at time t14. Here, for a mobile terminal that has already received policy P1 and has further received policy P2 and executed signaling processing to the core network, in addition to information on policy P1 and key information K1, information on policy P2 and key information K2 is included. Have been added. In addition, for the mobile terminal with the terminal identifier [5234789] that has newly received the policy P2 and newly connected, the information is registered, and the policy P2 and the key information K2 are associated as information of the related base station unit policy session. Registered.

  At this time, policy control is enabled by a combination of key information associated with each mobile terminal MN in a terminal unit policy session. For example, a mobile terminal MN having a terminal unit policy session associated with each of the key information K1 and the key information K2 can be grasped as a mobile terminal MN connected to the base station for a long time. Policy control is possible.

  Further, since the terminal unit policy session associated with only the key information K2 can be grasped as a mobile terminal connected to the base station after time t5, policy control based on it can be performed.

  Furthermore, for a terminal unit policy session that is associated only with the key information K1 and not associated with the key information K2, it has moved out of the cellular base station range after time t5, or communication via the wireless LAN interface IF2 is not possible. It is possible to grasp as a mobile terminal MN that does not exist, and policy control based on it can be performed.

  DESCRIPTION OF SYMBOLS 100 ... Policy request detection part, 101 ... Policy control part, 102 ... Policy transmission part, 103 ... Policy session management part, 104 ... 1st policy generation part, 105 ... Policy evaluation part, 106 ... 2nd policy generation part, 201 ... Information storage unit, 202 ... signaling processing determination unit, 203 ... signaling processing execution unit

Claims (11)

In a policy control method for applying policy control to a mobile terminal having a plurality of wireless interfaces and controlling a wireless interface used by each mobile terminal for connection to a core network,
Sending the first policy request to the policy server triggered by the congestion of the radio base station that accommodates the mobile terminal,
In response to the first policy request, the policy server creates a first policy to be applied to each mobile terminal located under the congested radio base station and associates it with the first key.
The policy server transmits the first policy and the first key to the mobile terminal under the congestion via the congested radio base station,
The mobile terminal that has received the first policy determines a wireless interface to be connected to the core network according to the first policy,
Each mobile terminal accesses the core network from the determined wireless interface using the first key as identification information,
A policy server identifying, based on the first key, a wireless interface through which each mobile terminal has accessed the core network;
A policy control method, wherein a policy server evaluates the first policy based on the identification result. The policy server creates a second policy to be applied to each mobile terminal located under the congested radio base station based on the evaluation result of the first policy and associates it with a second key,
The policy server transmits the second policy and the second key to the mobile terminal under the crowded radio base station,
The mobile terminal that has received the second policy determines a wireless interface to be connected to the core network according to the second policy,
Each mobile terminal accesses the core network from the determined wireless interface using the second key as identification information,
A policy server identifying, based on the second key, a wireless interface through which each mobile terminal has accessed the core network;
A policy control method, wherein a policy server evaluates the second policy based on the identification result.   The at least one of the first and second policies is a policy for switching a radio interface connected to a core network in each mobile terminal from one radio interface to another radio interface. Or the policy control method of 2.   The policy control method according to claim 1 or 2, wherein at least one of the first and second policies is a policy for adding a radio interface connected to a core network in each mobile terminal.   3. The policy control method according to claim 1, wherein at least one of the first and second policies is a policy for disconnecting a radio interface connected to a core network in each mobile terminal.   6. The policy control method according to claim 1, wherein the first and second policies are transmitted by broadcast to each mobile terminal.   The policy control method according to claim 1, wherein at least one of the plurality of wireless interfaces is an interface for cellular communication, and at least one of the plurality of wireless interfaces is a wireless LAN interface. In a policy server that transmits a policy to a mobile terminal having a plurality of wireless interfaces, and controls the wireless interface that each mobile terminal uses to connect to the core network,
Policy request detecting means for detecting a first policy request transmitted in response to congestion of a radio base station accommodating a mobile terminal;
In response to the first policy request, policy control means for creating a first policy to be applied to each mobile terminal located under the radio base station and associating it with a first key;
A policy server comprising policy transmission means for transmitting the first policy and the first key information to each mobile terminal under the radio base station. Policy evaluation means for evaluating the performance of the first policy based on the number of mobile terminals that have accessed the core network using the first key as authentication information;
Second policy generation means for generating a second policy that complements the results of the first policy based on the evaluation result of the first policy;
9. The policy server according to claim 8, wherein the policy transmission unit transmits the second policy to each mobile terminal under its control via the radio base station. In a mobile terminal comprising a plurality of wireless interfaces and controlling a wireless interface used for connection to a core network based on a policy notified from a policy server,
A policy receiving means for receiving the policy;
A signaling action determining means for determining a signaling action for controlling a radio interface used for connection to the core network based on the received policy;
A mobile terminal comprising: a signaling processing execution means for executing the determined signaling processing. Storage means for storing information for determining the signaling procedure;
The mobile terminal according to claim 10, wherein the signaling treatment determining means determines a signaling action based on the received policy and information stored in the storage means.