WO2005069513A1

WO2005069513A1 - Network control apparatus, communication terminal, and network selecting method

Info

Publication number: WO2005069513A1
Application number: PCT/JP2004/019520
Authority: WO
Inventors: Ming Qiang Xu; Sachiko Takeshita; Maki Amishima; Kentaro Takei
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2004-01-14
Filing date: 2004-12-27
Publication date: 2005-07-28

Abstract

A network control apparatus (10) comprising a SIP message processing part (16) for receiving a register message; a data forwarding part (12) for forwarding, with reference to a destination table produced based on the received register message, data to a communication terminal (30); a terminal information storing part (18) for storing information registered from the communication terminal (30) so as to select at least one of a plurality of networks having different communication systems; a network selection control part (22) for, when receiving a register message indicative of an entrance of the communication terminal (30) into a different network, selecting, based on the terminal information storing part (18), a network to be used for forwarding the data to the communication terminal (30); and an associating part (24) for updating the destination table so as to forward the data via the selected network.

Description

Specification

Network control device, communication terminal, and network selection method

Technical field

The present invention relates to a network control device that controls connection to a communication terminal connectable to a plurality of networks having different communication methods.

Background art

[0002] In the next-generation mopile network, a plurality of different networks are integrated by IP, and accordingly, it is considered that one mopile terminal accommodates a plurality of mopile network interfaces. In this case, if the communication terminal enters the area covered by 3G and WLAN (Wireless LAN) from the area covered by 3G (third generation) during the service, for example, it is determined whether or not the handover power is sufficient. Is required.

[0003] Japanese Patent Application Publication No. 11-501783, pp. 18-19, describes an invention relating to a handover method in a mobile communication system combining mobile communication networks that can belong to various mobile communication systems. The present invention uses at least one other parameter in addition to the quality of the connection as a parameter on which to base a decision on handover. Other parameters include data rate, connection price, connection speed, service, and so on.

Disclosure of the invention

Problems to be solved by the invention

[0004] However, the handover method described above does not disclose a specific method of how to switch to another communication network while maintaining the previous communication.

[0005] The present invention proposes a specific method for switching to a communication network selected based on set parameters.

Means for solving the problem

[0006] A network control device of the present invention includes a registration request receiving means for receiving a registration request for registering that a communication terminal is a terminal connected to a network; A destination table created on the basis of the registration request received by the communication means; a transfer means for referring to the destination table to transfer data to a communication terminal connectable to a plurality of networks having different communication methods; A communication terminal capable of storing at least one of the communication terminals registered in order to select at least one of the networks; and a network other than the network in which the communication terminal is performing data communication. When the registration request receiving unit receives a registration request to the other network, the network used to transfer data to the communication terminal is determined based on the information stored in the network selection information storage unit. A network selecting means to be selected, and a network selected by the network selecting means. And a table updating means for updating the destination table to transfer data through.

[0007] As described above, the configuration in which the communication terminal is connected to a network having a different communication method during communication is managed by managing a network to which the communication terminal is connected and specifying a destination table to specify a destination to which data is to be transmitted. In this case, by rewriting the destination table of the network control device that transfers data to the communication terminal without reestablishing a connection between the communication terminal and the communication partner that entered the different network. In addition, since switching to a network using a different communication method can be performed, the network can be switched at high speed while maintaining communication. In addition, by deciding whether or not to switch networks based on the selection information registered for each communication terminal, it is possible to switch to a network that meets the needs of the communication terminals.

[0008] The network selection information storage means stores information on the intensity of radio waves received by the communication terminal through each of a plurality of networks, and the network selection means stores the information in the network selection information storage means. You can select a network based on the information about the signal strength! /.

With this configuration, it is possible to select a stable network according to the constantly changing situation of the communication terminal.

[0010] The network selection information storage means stores information on radio field intensity required for communication for each communication type, and the network selection means determines a communication type during data communication by the communication terminal. Signal strength required for different types of communication and the The network may be selected based on the information on the strength of the last radio wave.

[0011] According to this configuration, a network having a required radio field intensity can be selected according to the communication type, so that stable communication can be performed even after the network is switched. The communication type is information on communication contents such as multimedia communication and voice communication.

[0012] The network selection information storage means stores information related to network security required for communication, and the network selection means selects a network based on the security information stored in the network selection information storage means. May

With this configuration, a network having communication security desired by the user of the communication terminal can be selected.

[0014] The network selection information storage means stores the information on security in association with information on a terminal of a communication partner, and the network selection means stores information on security required for communication of the communication terminal with a communication partner. The network selection information storage means is extracted, and a network is selected based on the extracted information on security.

[0015] With this configuration, it is possible to select a network provided with communication security desired by the user of the communication terminal in accordance with the communication partner.

[0016] The network selection information storage means stores information on the security for each communication type, the network selection means determines a communication type during data communication by the communication terminal, and determines a communication type of the determined type. The information relating to security required for the network selection information storage means may be extracted, and a network may be selected based on the extracted information relating to security!

[0017] With this configuration, a network having communication security desired by the user of the communication terminal can be selected according to the communication type.

[0018] The network selection information storage means stores information on a communication speed of a network necessary for communication, and the network selection means stores the information on the communication speed stored in the network selection information storage means. May be used to select a network.

With this configuration, a network provided with a communication speed of communication desired by the user of the communication terminal is secured. Can be selected.

[0020] The network selection information storage means stores the information on the communication speed in association with information on the terminal of the communication partner, and the network selection means stores information required for communication with the terminal of the communication terminal of the communication terminal. Information on the communication speed is extracted from the network selection information storage means, and a network is selected based on the extracted information on the communication speed.

According to this configuration, a network having a communication speed of communication desired by the user of the communication terminal can be selected according to a communication partner.

[0022] The network selection information storage means stores information on the communication speed for each communication type, and the network selection means determines a communication type during data communication by the communication terminal, and determines the type of the determined type. Extracting information on the communication speed required for communication from the network selection information storage means, and selecting a network based on the extracted information on the communication speed;

According to this configuration, a network having a communication speed of communication desired by the user of the communication terminal can be selected according to the communication type.

[0024] The network selection information storage means stores information on the priority of a plurality of selection criteria for selecting the network, and the network selection means stores the priority stored in the network selection information storage means. May be applied in the order of higher selection criteria to select the network.

[0025] With this configuration, priorities can be set for a plurality of selection criteria, and it is possible to flexibly respond to user requests.

[0026] The communication terminal of the present invention includes a lower layer information collection unit that detects the intensity of radio waves received through at least one of a plurality of networks using different communication methods, Using a network selection information storage unit storing a user request condition for selecting one, and a radio wave intensity detected by the lower layer information collection unit, the network selection information storage unit separates from a network during data communication with a partner terminal. Detecting means for detecting that the user has entered the other network; and detecting the user request conditions stored in the network selection information storing means when the detecting means detects that the user has entered another network. Network selection means for selecting a network to use for receiving data based on the signal strength detected by the signal strength detection means, and registration that the communication terminal is a terminal connected to the network. The destination table of the network control device, which is updated based on the registration request and is referred to when the network control device transferring the data from the partner terminal transmits the data, is selected by the network selecting means. Update message transmitting means for transmitting an update message for updating to receive data through a network to the network control device.

As described above, by transmitting the update message for updating the destination table to the network control device having the destination table to be referred to when transmitting data to the communication terminal, the network is switched. However, if a user enters a network with a different communication method during communication, the communication terminal maintains the communication at a high speed without re-establishing a connection between the communication terminal and the communication partner in the different network. Can be switched. Also, by determining whether or not to switch the network based on the preregistered selection information, it is possible to switch to a network that meets the needs of the user.

[0028] The communication terminal includes a radio wave intensity detection unit that detects the intensity of a radio wave received through at least one of the plurality of networks, and the network selection information storage unit includes a radio wave intensity detection unit. The information on the detected radio wave intensity may be stored, and the network selection unit may select a network based on the information on the radio wave intensity stored in the network selection information storage unit.

[0029] With this configuration, a stable network can be selected according to the constantly changing situation of the communication terminal.

[0030] The network selection information storage means stores information on radio field intensity required for communication for each communication type, and the network selection means determines a communication type during data communication, and determines the type of the determined type. The network may be selected based on the radio wave intensity required for communication and the information on the radio wave intensity!

[0031] According to this configuration, a network having a required radio field intensity can be selected according to the communication type, so that stable communication can be performed even after the network is switched. Communication type is For example, it is information on communication contents such as multimedia communication and voice communication.

[0032] The network selection information storage means stores information relating to network security required for communication, and the network selection means selects a network based on the security information stored in the network selection information storage means. May

[0033] With this configuration, a network having communication security desired by the user can be selected.

[0034] The network selection information storage unit stores the security-related information in association with information about a communication partner terminal, and the network selection unit stores security-related information necessary for communication with the communication partner terminal in the network. Selection information storage means Power may be extracted and a network may be selected based on the extracted information on security.

With this configuration, a network having communication security desired by the user can be selected according to the communication partner.

[0036] The network selection information storage means stores information on the security for each communication type, the network selection means determines a communication type during data communication, and determines a security required for communication of the determined type. Information on the network selection information storage means, and select a network based on the extracted information on security.

With this configuration, it is possible to select a network having communication security desired by the user according to the communication type.

[0038] The network selection information storage means stores information on the communication speed of a network required for communication, and the network selection means stores the information on the communication speed stored in the network selection information storage means. May be used to select a network.

[0039] With this configuration, it is possible to select a network having a communication speed of communication desired by the user.

[0040] The network selection information storage means stores the information about the communication speed in association with information about the terminal of the communication partner, and the network selection means stores the information of the communication partner. Information on the communication speed required for communication with the terminal may be extracted from the network selection information storage means, and a network may be selected based on the extracted information on the communication speed.

With this configuration, it is possible to select a network having a communication speed of communication desired by the user according to a communication partner.

[0042] The network selection information storage means stores information on the communication speed for each communication type, the network selection means determines a communication type during data communication, and is necessary for communication of the determined type. Information on the communication speed may be extracted from the network selection information storage means, and a network may be selected based on the extracted information on the communication speed.

With this configuration, it is possible to select a network having a communication speed desired by the user according to the communication type.

[0044] The network selection information storage means stores information on the priority of a plurality of selection criteria for selecting the network, and the network selection means stores the priority stored in the network selection information storage means. May be applied in the order of higher selection criteria to select the network.

[0045] With this configuration, priorities can be set for a plurality of selection criteria, and it is possible to flexibly respond to user requests.

[0046] The network system of the present invention includes: a communication terminal capable of performing communication through a plurality of networks having different communication methods; and a network control device that controls connection of the communication terminal to the network. The communication terminal includes: a lower layer information collection unit that detects the intensity of a radio wave received through at least one of the plurality of networks; and a radio terminal that uses the radio wave intensity detected by the lower layer information collection unit to communicate with the partner terminal. A detecting means for detecting entry into a different network from the data communication network; and a communication terminal connected to the network when the detecting means detects entry into another network. Registration request transmitting means for transmitting a registration request for registering that the network control device, A registration request receiving means for receiving the registration request transmitted from the communication terminal, received by the registration request receiving unit A destination table created on the basis of the registration request, and transfer means for referring to the destination table to transfer data to a communication terminal connectable to a plurality of networks having different communication methods; and Network selection information storage means for storing the registered information to select at least one of the networks; and When a registration request to the another network is received by the registration request receiving unit, a network used to transfer data to the communication terminal is determined based on information stored in the network selection information storage unit. Network selecting means for selecting data, and transmitting data through the network selected by the network selecting means. And a table updating means for updating the destination table to feed.

[0047] With this configuration, similarly to the network control device of the present invention, it is possible to switch to a network with a different communication method at high speed while maintaining communication, and to switch to a network that meets the needs of the communication terminal. I can do it. The above-described various configurations of the network control device of the present invention can be applied to the network system of the present invention.

[0048] A network selection method according to the present invention is a method in which a network control device that controls connection to a communication terminal connectable to a plurality of networks having different communication methods selects a network to be connected to the communication terminal. A registration request receiving step for receiving from the communication terminal a registration request for registering that the communication terminal is a terminal connected to the network; and a registration request received in the registration request receiving step. Creating a destination table, transferring the data to the communication terminal with reference to the destination table, and entering a network different from the network in which the communication terminal is performing data communication. Receiving the registration request to the other network, indicating that the communication terminal has A network selection step of selecting a network to be used for transferring data to the communication terminal based on the registered information; and transferring the data through the network selected in the network selection step. And a table updating step of updating the destination table.

[0049] With this configuration, similar to the network control device of the present invention, communication is maintained while maintaining communication. High-speed switching to a network with a different system is possible, and switching to a network that meets the needs of communication terminals can be performed. Note that the above-described various configurations of the network control device of the present invention can be applied to the network selection method of the present invention.

[0050] A network selection method according to another aspect of the present invention relates to a network used by a communication terminal connected to a network control device that controls connection to a communication terminal connectable to a plurality of networks using different communication methods for communication. A detecting step of detecting entry into a network different from the network in which data communication with the partner terminal is performed, and a step of detecting entry into another network in the detection step. A network selection step of selecting a network to use for receiving data based on information for selecting one network registered in advance, and determining that the communication terminal is a terminal connected to the network. The network control device transmits data while being updated based on a registration request for registration An update message for transmitting, to the network control device, an update message for updating a destination table of the network control device to be referred to at the time of the network selection step so as to receive data through the selected network. Message transmitting step.

[0051] With this configuration, similarly to the communication terminal of the present invention, it is possible to switch to a network with a different communication method at high speed while maintaining communication, and to switch to a network that meets the needs of the user. Note that the above-described various configurations of the communication terminal of the present invention can be applied to the network selection method of the present invention.

According to the present invention, a network management device that controls a communication terminal connectable to a plurality of networks having different communication systems manages which network the communication terminal is connected to, and transmits data to which destination. With a configuration that has a destination table that specifies whether to transmit, when entering a network with a different communication method during communication, the connection between the communication terminal that has entered the different network and the other party can be reestablished. Also, by rewriting the destination table of the network control device that transfers data to the communication partner communication terminal, there is an excellent effect that the network can be switched at high speed while maintaining communication. In addition, by determining whether or not the ability to switch networks based on the selection information registered in advance for each communication terminal, a network that meets the needs of the communication terminal is determined. It has an excellent effect of being able to switch to a work.

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of a network control device according to a first embodiment.

[FIG. 2] FIG. 2 is a diagram showing an environment to which a network control device and a communication terminal of the present invention are applied.

FIG. 3 is a diagram showing an example of a routing table

FIG. 4 is a diagram showing an example of terminal information

[FIG. 5] FIG. 5 is a diagram showing an example of network selection information.

[FIG. 6] FIG. 6 is a diagram showing an example of network information

FIG. 7 is a diagram showing a configuration of a communication terminal according to the first embodiment.

FIG. 8 is a diagram showing operations of the network control device and the communication terminal according to the first embodiment.

[FIG. 9] FIG. 9 is a diagram showing a sequence of a register message.

FIG. 10 shows an example of a register message transmitted in the first embodiment.

FIG. 11 is a diagram showing a configuration of a communication terminal according to a second embodiment.

FIG. 12 is a diagram showing a configuration of a network control device according to a second embodiment.

FIG. 13 is a diagram showing operations of a network control device and a communication terminal according to the second embodiment.

FIG. 14 shows an example of a register message transmitted in the second embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a network control device and a communication terminal according to an embodiment of the present invention will be described.

FIG. 1 is a diagram illustrating a configuration of the network control device 10 according to the first embodiment. Before describing the configuration of the network control device 10 according to the first embodiment, an environment in which the network control device 10 and the communication terminal 30 according to the embodiment are applied will be described. FIG. 2 is a diagram showing an environment to which the network control device 10 and the communication terminal 30 according to the embodiment of the present invention are applied. FIG. 2 shows a system in which a communication terminal 30 connectable to two networks and a communication terminal 70 connected to an ISP (Internet Service Provider) communicate.

[0057] The communication terminal 30 is a terminal that can be connected to a plurality of communication networks of different communication schemes. Here, the communication terminal 30 is connectable to a 3G network and a WLAN network. The communication terminal 30 is managed by one number. That is, regardless of which network is used for communication, the communication terminal 30 can be accessed with the same number. The communication terminal 30 is an IP-compatible terminal. The communication terminal 30 is, for example, a mobile phone terminal, an IP telephone terminal, a PDA having a function of connecting to a wireless network, a computer capable of connecting to a network, or an Internet home appliance. The communication terminal 70 is connected to an ISP. Note that the communication terminal 70 may be connected by another carrier other than the ISP.

As shown in FIG. 2, in the network environment of the present embodiment, a center 60 that manages a plurality of networks is provided. The center 60 integrally manages authentication, charging, session management, QoS control, and the like in a plurality of networks. Network control device 10 of the present embodiment is installed in center 60. The network control device 10 is a device that manages the establishment and disconnection of a session, and performs network switching. Further, the network control device 10 has a function of transmitting and receiving a SIP message.

[0059] Referring to FIG. 1, the network control device 10 will be described. The network control device 10 is a device having a function of a session management device for interworking a 3G network and a WLAN network, and a function of a data routing device. The network control device 10 has a SIP proxy, and establishes, disconnects, and routes a session using SIP.

As shown in FIG. 1, the network control device 10 includes a data transfer unit 12, a message transfer unit 14, a SIP message processing unit 16, a terminal information storage unit 18, a network information collection and storage unit 20, , A network selection control unit 22 and a cooperation unit 24. The network controller 10 not shown also has the same configuration as the ordinary network controller 10, such as a storage unit for storing information about the network (communication charges, bandwidth, etc.). The

[0061] The data transfer unit 12 has a function of transmitting and receiving data and transferring data based on a routing table.

FIG. 3 is a diagram showing an example of a routing table included in the data transfer unit 12. The routing table is a table for controlling data routing. In the “communication terminal” of the routing table, the IP address and port number of the communication terminal 30 controlled by the network control device 10 are written, and in the “communication partner terminal”, the communication terminal 70 communicating with the communication terminal 30 is written. IP address and Port Number are written. This routing table is updated when a network handover is performed. When a new network is entered and handover to the new network is determined, the new network is set as the data transfer path. That is, the network path is written in the routing table, and the network path before the handover is deleted. By updating the routing table in this way, a new data path is established.

[0063] The message transfer unit 14 has a function of performing a process of creating a transmission message as a packet and a process of creating a received packet as a message.

The SIP message processing unit 16 has a function of extracting radio field intensity information from the received register message power and storing the information in the terminal information storage unit 18. The register message is a SIP protocol message for registering that the terminal is connected to the network. By this register message, the network control device 10 detects a change in the area where the communication terminal 30 exists. That is, the register message triggers the handover decision of the network. Further, the SIP message processing unit 16 has a function of extracting information of a caller, a callee, and an application type from the received invite message and storing the information in the terminal information storage unit 18. The Invite message is a SIP protocol message that requests the start of communication.

The terminal information storage unit 18 has a function of storing terminal information used for network selection transmitted from the communication terminal 30 and a table of network selection conditions for selecting a network. FIG. 4 is a diagram showing an example of information stored in the terminal information storage unit 18. In this example, information such as “user type”, “communication partner”, “application”, “currently used NW information”, and “candidate NW information” is stored as terminal information. “User type” is information for identifying a user. “Communication partner” is information indicating the communication partner of the communication terminal 30 of the user indicated by the user type. “Application” is information on the application in communication. Here, information indicating that the “voice service” is being performed is stored. In addition to the audio service, for example, an application such as videophone streaming distribution can be realized. Note that the information of “communication partner” and “application” is dynamic information on the session, and the power of the Innotate message is also extracted. The “currently used NW information” is information of a network used by the communication terminal 30, and the “candidate NW information” is information of a new network in which the communication terminal 30 has entered. Each of the network information includes information on the radio wave intensity that the communication terminal 30 is receiving through the network. Here, information indicating that the radio wave intensity received through the 3G network is “E1” and the radio wave intensity received through the WLAN network is “E2” is stored. The “currently used NW information” and the “candidate NW information” are updated by the signal strength information extracted by the SIP message processing unit 16 from the register message. The register message is notified from the communication terminal 30 from the communication terminal 30 periodically or when the radio wave intensity changes beyond a predetermined threshold.

FIG. 5 is a diagram showing an example of network selection information stored in the terminal information storage unit 18. In this example, information of “user type” ユーザ ο. ”,“ Communication condition ”,“ application ”,“ network switching condition ”, and“ bandwidth used ”are set in the network selection information. “User type” is information for identifying a user. “ΓΝο.” Is a number that identifies the network selection criterion. The “communication condition” is information on the priority of communication that determines a criterion for switching networks. Here, a high priority “H” is set for communication with the registered members “al”, “bl”, and “cl”, and a low priority “L” is set for communication with others. Registration of a member with a high priority is performed by a user. “Application” refers to the application that determines the criteria for switching networks. Information. Applications include, for example, voice calls or videophones, as shown in FIG. “Network switching condition” is information that defines the criteria for switching networks. For example, No. 1 stipulates that a highly confidential network should be selected. As shown in Fig. 5, there are three criteria for switching networks: “confidentiality”, “charge”, and “data rate”. If conditions are specified in two or more items, switch to a network that satisfies all of the conditions. In addition, when a condition is defined by two or more items, the network control device 10 can be designed to switch to a network that satisfies one of the plurality of conditions. In this case, it is desirable to determine in advance the items to be determined with priority. “Usage bandwidth” is information on the bandwidth required for the selected network. Therefore, even if the network satisfies the network switching conditions, switching to that network cannot be performed if the bandwidth specified in the used bandwidth cannot be secured. The network selection information shown in Fig. 5 is set by the user. As a setting method, the network selection information may be set via the Internet, or the network selection information may be registered by contacting the operator of the network control device 10. Further, when the user purchases the communication terminal 30, it is also possible to register the contract details at the time of purchase and the set network selection condition information 30. Alternatively, when the communication terminal 30 is registered as a terminal connected to the network, it is possible to notify the selection condition. In the present embodiment, the mode in which the switching condition can be set for each user has been described. However, the network switching condition is common to all users, and only the information of the communication partner with a high communication priority can be set for each user. You can also.

The network information collection / storage unit 20 has a function of collecting and storing information on the usage status of the network managed by the network control device 10. FIG. 6 is a diagram showing an example of information stored in the network information collection and storage unit 20. In this example, information on “network type”, “confidentiality”, “fee”, “data rate”, and “usable band” is accumulated as network information. “Network type” is information for identifying a network. The information on “confidentiality”, “fee”, and “data rate” is information about the network and is static information determined by the network. According to this example, the 3G network It can be seen that the network has the characteristics of confidentiality, high fee, and data rate of 384kbps. “Available bandwidth” is information on the currently available bandwidth, and changes depending on the situation at that time. In this example, it can be seen that the 3G network can currently use a bandwidth of 384k (bps). In addition, it can be seen that the WLAN network cannot use the maximum bandwidth of 10 Mbps and can now communicate at 8 Mbps. Information that changes according to the situation, such as available bandwidth, is periodically collected by the network information collection and storage unit 20.

The network selection control unit 22 has a function of selecting a network to be connected to the communication terminal 30 based on information stored in the terminal information storage unit 18 and information stored in the network information collection storage unit 20. Have. As described above, by performing routing based on the information obtained from the terminal information storage unit 18 and the network selection information storage unit 20, the network selection control unit 22 performs routing using a network according to the request of the communication terminal 30. Can be performed. An example of network selection by the network selection control unit 22 will be described in the description of the operation of the network control device 10.

[0070] The linking unit 24 has a function of updating the packet routing table of the data transfer unit 12 based on the judgment of the network selection control unit 22, which is an application layer.

Next, the communication terminal 30 according to the first embodiment will be described. FIG. 7 is a diagram illustrating a configuration of the communication terminal 30 according to the first embodiment. As shown in FIG. 7, the communication terminal 30 has a hierarchical configuration. The upper layer 32 corresponds to the application layer of the OSI reference model, and the lower layer 40 corresponds to the transport layer to the physical layer of the OSI reference model. Further, the communication terminal 30 includes a lower layer information collecting unit 50 that collects information of the lower layer 40 between the upper layer 32 and the lower layer 40.

The communication terminal 30 has a user interface 38, a notification control unit 34, and an application 36 in the upper layer 32. The communication terminal 30 has a communication protocol control unit 42, a radio interface control unit 44, a 3G interface 46, and a WLAN interface 48 in the lower layer 40. Hereinafter, each component of the communication terminal 30 will be described.

[0073] The notification control unit 34 uses the NW information used by the communication terminal 30 as the NW information and the NW information as a candidate. It has a function of notifying the network controller 10 of information and media transfer IP address information.

[0074] The application 36 has a function of providing conditions and service logic required for an application executed by communication.

[0075] The user interface 38 has a function of receiving input from a user and outputting information to the user.

[0076] The communication protocol control unit 42 has a function of controlling a communication protocol in the wireless interface. The communication protocol control unit 42 corresponds to the transport layer and the network layer of the OSI reference model.

[0077] The wireless interface control unit 44 has a function of controlling a wireless interface necessary for performing wireless communication. The wireless interface control unit 44 corresponds to the data link layer of the OSI reference model.

[0078] The 3G interface 46 is a wireless interface for accessing a 3G network, and the WLAN interface 48 is a wireless interface for accessing a WLAN network. The two interfaces 46, 48 correspond to the physical layer of the OSI reference model.

The lower layer information collecting unit 50 has a function of monitoring and collecting information on the data link layer and the physical layer of the wireless interface, for example, radio wave intensity information. The lower layer information collection unit 50

Then, the collected information is input to the notification control unit 34.

Next, operations of the network control device 10 and the communication terminal 30 according to the present embodiment will be described. FIG. 8 is a diagram illustrating operations of the network control device 10 and the communication terminal 30.

The communication terminal 30 monitors the radio field intensity by the lower layer information collection unit 50, and determines whether or not the communication terminal 30 has entered a new network (S10). When entering a new network, the communication terminal 30 acquires a new network IP address (S12).

Next, the communication terminal 30 generates a message in which the acquired IP address and the IP address of the network in use are described in the “Contact” item of the header of the register message, and transmits the message to the network control device 10 (S14). Here, the sequence of the SIP register message will be described with reference to FIG. As shown in FIG. 9, the communication terminal 30 transmits a register message to the network control device 10, and upon receiving the register message, the network control device 10 registers the communication terminal 30 of the transmission source and transmits 200OK as a success response. . Thus, the sequence of the register message is completed.

FIG. 10 is a diagram showing the register message transmitted here. In the header of the register message, in addition to the “Contact” item, “Fromj and“ To ”items describing the URI of the communication terminal 30 of the transmission source, and information on the period for requesting registration are described. iresj t \, have items. Here, the value is described in “Expires”. This means registering for an indefinite period.

[0085] In SIP, a body is a part that can describe information extended from standard information. In the body of the register message, information on the application in use, the media transfer IP address, the radio wave intensity of the NW currently used, and information on the radio wave intensity of the NW that is a candidate are described. The media transfer IP address is information described when it is different from the network IP address.

[0086] The network control device 10 receives the register message transmitted from the communication terminal 30 by the data transfer unit 12, and inputs the register message to the SIP message processing unit 16 via the message transfer unit 14. The SIP message processing unit 16 extracts the information of the header and the body of the received register message, and transmits the extracted information to the network selection control unit 22 (S16).

[0087] In order to determine whether or not to hand over to a new network enabled by the communication terminal 30, the network selection control unit 22 first sends the information to the terminal information storage unit 18 and the network information collection and storage unit 20. Then, a request is made to acquire terminal information, network selection information, and network information (S18). The network information collection / storage unit 20 transmits the information on the network side to the network selection control unit 22 (S20), and the terminal information storage unit 18 transmits the terminal information and the information in the selection table to the network selection control unit 22 ( S22). Next, the network selection control unit 22 selects a network to be used based on the acquired information (S24).

Here, an example of selecting a network will be described. Here, the communication terminal 30 is connected to the end of FIG. An example of selecting a network to be used when the communication indicated in the terminal information is being performed will be described. First, a network in which the communication terminal 30 of the user 1 exists will be described. Referring to “NW information currently in use” and “NW information as a candidate! / Puru NW information” in FIG. 4, it can be seen that, when communication terminal 30 of user 1 is using the 3G network, WLAN You can see that the network has entered the available area. In this example, it is determined whether the communication terminal of the user 1 should use the ^ G network by referring to the network selection information (see FIG. 5).

[0089] The communication partner al of the user 1 is a communication partner having a high communication priority according to the network selection information shown in FIG. The application being communicated is a voice service. Therefore, the network selection control unit 22 selects a network based on the criterion that the confidentiality of “No. 1” in the network selection information shown in FIG. 5 is high. Here, referring to the network information stored in the network information storage unit 20 shown in FIG. 6, it can be seen that the 3G network has higher confidentiality than the WLAN network. Therefore, the network selection control unit 22 determines that the 3G network should be selected. Although the available bandwidth is not specified in “No. 1” of the network selection information, for example, when the available bandwidth is specified as in the “No. 2” standard, Judge whether the current bandwidth of the selected network exceeds the specified bandwidth or not, and if it exceeds the defined bandwidth, finally select the network.

After determining the network to be used, the network selection control unit 22 determines whether to perform a handover (S26). If the currently used network and the selected network are different, it is determined that handover will be performed, and if they are the same, it is determined that handover will not be performed. If it is determined that the handover is to be performed, the network selection control unit 22 rewrites the routing table of the data transfer unit 12 in the network layer by the cooperation unit 24 between the upper layer 32 and the lower layer 40 (S28). The linking unit 24 rewrites the routing table used by the data transfer unit 12 based on the routing table update request from the network selection control unit 22 using the socket. The data transfer unit 12 writes a new routing path in the routing table and deletes the routing path before the handover. Then, the data transfer unit 12 writes the data of the communication partner into the routing table. The new data is transferred by the data path (S30).

[0091] In an actual mopile network, AAA (Authentication, Authorization, and

Procedures that require procedures such as Accounting) and QoS assurance These are stipulated in the standard, and shall conform to the following methods.

[0092] The communication terminal 30 and the network control device 10 according to the first embodiment have been described above.

The network control device 10 according to the first embodiment stores the network selection information registered from the communication terminal 30 in the terminal information storage unit 18 and, based on the stored network selection information, Select the network to connect to 30. This makes it possible to select a network that meets the needs of the communication terminal 30.

[0094] In the above, the network selection control unit 22 of the network control device 10 selects the network based on the information described in the example of selecting a network based on the information on the priority and the application and the other information as a reference. You can.

[0095] Since the network control device 10 receives the radio wave intensity information transmitted from the communication terminal 30 and stores it in the terminal storage information section, it is also possible to select a network based on this radio wave intensity information. is there. For example, when it is determined that a plurality of networks can be used by priority or an application, a network having a high radio field intensity may be selected. Thereby, communication after handover can be performed stably.

[0096] In the above-described first embodiment, an example in which communication terminal 30 is controlled by network control device 10 has been described. However, communication terminal 30 performing communication and communication terminal 70 are both controlled by network control device 10. It may be controlled to 10. In this case, when the network of the communication terminal 30 or the communication terminal 70 changes, the routing table is rewritten.

Next, a description will be given of a network control device 10 and a communication terminal 30 according to a second embodiment of the present invention. The communication terminal 30 according to the second embodiment is a communication terminal 30 that determines whether or not to perform a handover based on network selection information set in advance when entering a new network. The environment to which the network control device 10 and the communication terminal 30 of the second embodiment are applied is the same as that of the first embodiment (see FIG. 2). FIG. 11 is a diagram illustrating a configuration of a communication terminal 30 according to the second embodiment. The communication terminal 30 according to the second embodiment has the same basic configuration as the communication terminal 30 according to the first embodiment. Instead of the power notification control unit 34, an NW selection notification unit having a network selection function is provided. The difference is that the setting information storage unit 52 is further provided.

[0099] The setting information storage unit 52 stores the terminal information (see FIG. 4) and the network selection information (see FIG. 5) stored in the terminal information storage unit 18 of the network control device 10 of the first embodiment. Has been accumulated. The network selection information is set by the user through the user interface 38. Further, the setting information storage unit 52 stores the network information of the network information collection and storage unit 20 (see FIG. 6) of the network control device 10 of the first embodiment. Preferably, the network information is updated upon receiving a notification from the network control device 10.

[0100] When detecting that communication terminal 30 has entered a new network, NW selection notifying section 54 determines whether or not to perform a handover using information accumulated in setting information accumulating section 52. Has functions. Further, the NW selection notifying unit 54 has a function of creating and transmitting a register message for causing the network control device 10 to update the routing table when it is determined that handover is to be performed.

[0101] Next, the network control device 10 will be described. FIG. 12 is a diagram illustrating a configuration of a network control device 10 according to the second embodiment. The network control device 10 includes a data transfer unit 12, a message transfer unit 14, a SIP message processing unit 16, a network selection control unit 22, and a cooperation unit 24. The network control device 10 used in the second embodiment is a normal network control device.

[0102] The network selection control unit 22 has a function of activating the rewriting of the routing table based on the handover information included in the register message from the communication terminal 30. The linking unit 24 has a function of rewriting the routing table of the data transfer unit 12 based on the activation of the network selection control unit 22.

Next, operations of the network control device 10 and the communication terminal 30 according to the second embodiment will be described. FIG. 13 shows operations of the network control device 10 and the communication terminal 30. FIG.

The communication terminal 30 monitors the radio field intensity by the lower layer information collection unit 50, and determines whether the communication terminal 30 has entered a new network (S40). When entering a new network, the communication terminal 30 acquires a new network IP address (S42).

[0105] Next, the NW selection notifying unit 54 of the communication terminal 30 requests the setting information storage unit 52 to acquire the network selection information in order to judge whether the handover to the newly entered network is possible or not. Request for the type of application and information on the communication partner (S44). The setting information storage unit 52 transmits the selection conditions set by the user to the NW selection notification unit 54, and the application 36 transmits the application information to the NW selection notification unit 54 (S48).

Subsequently, the communication terminal 30 determines whether to perform a handover based on the acquired information (S50). The determination method is the same as the method determined by the network control device 10 in the first embodiment.

[0107] When the NW selection notifying unit 54 determines that a handover has occurred, the communication terminal 30 creates a register message for notification to the network control device 10, and transmits the message to the network control device 10 (S52).

FIG. 14 is a diagram showing an example of a register message created to instruct a handover. The message created by the NW selection notifying unit 54 is a SIP register message. The information of the telephone number of the communication terminal 30 is described in the item of “From” WTo ”of the header, and the IP address for transmitting and receiving the SIP message is described in the item of“ Contact ”. If the IP address for media reception is different from the above SIP address, describe the IP address for media transfer in the body.

The network control device 10 receives the register message transmitted from the communication terminal 30 by the data transfer unit 12, and inputs the register message to the SIP message processing unit 16 via the message transfer unit 14. The SIP message processing unit 16 extracts the header and body information from the register message and transmits the information to the network selection control unit 22 (S54).

[0110] The network selection control unit 22 rewrites the routing table of the data transfer unit 12 by the cooperation unit 24 between the network selection control unit 22 and the data transfer unit 12. Coordination Department 24 The routing table used by the data transfer unit 12 is rewritten based on the routing table update request from the network selection control unit 22 using the socket (S56). The data transfer unit 12 writes a new routing path in the routing table and deletes the routing path before the handover. Then, the data transfer unit 12 transfers the data from the communication partner through the new data path written in the routing table (S58).

[0111] In an actual mopile network, procedures such as securing AAA and QoS are also required, but these procedures are assumed to conform to the method specified in the standard.

[0112] The communication terminal 30 and the network control device 10 according to the second embodiment have been described above.

[0113] The communication terminal 30 according to the second embodiment stores network selection information registered by the user in the setting information storage unit 52, and establishes a connection based on the stored network selection information. The network to be used is selected, and the handover capability is determined. This makes it possible to select a network that meets the needs of the communication terminal 30.

Industrial applicability

[0114] As described above, the present invention provides a high-speed network while maintaining communication without re-establishing a connection between a communication terminal that has entered a network using a different communication method and its communication partner. It has an excellent effect of being able to switch between different communication methods, and is useful as a network control device or the like that controls connection to communication terminals that can be connected to a plurality of networks using different communication methods.

Claims

The scope of the claims

[1] a registration request receiving means for receiving a registration request for registering that the communication terminal is a terminal connected to the network;

A destination table created based on the registration request received by the registration request receiving means,

Transfer means for transferring data to a communication terminal connectable to a plurality of networks having different communication schemes with reference to the destination table;

Network selection information storage means storing information registered from the communication terminal to select at least one of the plurality of networks,

Transferring data to the communication terminal when the registration request receiving means receives a registration request for the another network indicating that the communication terminal has entered a network different from the network in which data communication is being performed; Selection means for selecting a network to be used based on the information stored in the network selection information storage means, and a table update for updating the destination table so as to transfer data through the network selected by the network selection means. Means,

A network control device comprising:

[2] The network selection information storage means stores information on the strength of radio waves received by the communication terminal through each of a plurality of networks,

The network selection means selects a network based on information on the intensity of the radio wave stored in the network selection information storage means;

The network control device according to claim 1, wherein:

[3] The network selection information storage means stores information on radio field intensity required for communication for each communication type,

The network selection means determines a communication type during data communication by the communication terminal, and establishes a network based on radio wave intensity required for communication of the determined type and information on radio wave intensity of the communication terminal. select,

3. The network control device according to claim 2, wherein:

[4] The network selection information storage means is provided for securing network security required for communication. Store information about

The network selection unit selects a network based on information on security stored in the network selection information storage unit;

The network control device according to claim 1, wherein:

[5] The network selection information storage means stores the information about the security in association with information about the terminal of the communication partner,

The network selection means extracts information on security required for communication of the communication terminal with a communication partner with the network selection information storage means, and selects a network based on the extracted information on security.

5. The network control device according to claim 4, wherein:

[6] The network selection information storage means stores the information on the security for each communication type,

The network selection means determines a communication type during data communication by the communication terminal, extracts information related to security necessary for communication of the determined type, from the network selection information storage means, and extracts the extracted information related to security. Select a network based on

5. The network control device according to claim 4, wherein:

[7] The network selection information storage means stores information on a network communication speed required for communication,

The network selection means selects a network based on the communication speed information stored in the network selection information storage means;

The network control device according to claim 1, wherein:

[8] The network selection information storage means stores information on the communication speed in association with information on a terminal of a communication partner,

The network selecting unit extracts information on a communication speed required for communication of the communication terminal with a communication partner terminal from the network selection information storage unit, and selects a network based on the extracted information on the communication speed.

8. The network control device according to claim 7, wherein: [9] The network selection information storage means stores information on the communication speed for each communication type,

The network selection means determines a communication type during data communication by the communication terminal, extracts information relating to a communication speed required for communication of the determined type from the network selection information storage means, and extracts the extracted communication. Select a network based on speed information,

8. The network control device according to claim 7, wherein:

[10] The network selection information storage means stores information on the priority of a plurality of selection criteria for selecting the network,

2. The network control device according to claim 1, wherein the network selection unit selects the network by applying the selection criterion in descending order of priority stored in the network selection information storage unit.

[11] lower-layer information collecting means for detecting the intensity of radio waves received through at least one of a plurality of networks having different communication methods;

A network selection information storage unit storing a user request condition for selecting one of a plurality of networks having different communication methods,

A detecting unit that detects, by using the radio wave intensity detected by the lower layer information collecting unit, that the mobile terminal has entered a network different from the network that is performing data communication with the partner terminal; A network used to receive data based on the user request conditions stored in the network selection information storage unit and the radio wave intensity detected by the radio wave intensity detection unit when the input is detected. A network selection means,

The network which is updated based on a registration request for registering that the communication terminal is a terminal connected to the network, and which is referred to when the network control device for transferring data from the partner terminal transmits data is referred to. Update message transmitting means for transmitting, to the network control device, an update message for updating the destination table of the control device so as to receive data through the network selected by the network selecting device; A communication terminal comprising:

[12] The network selection information storage means stores information on radio field intensity required for communication for each communication type,

The network selecting means determines a communication type during data communication, and selects a network based on radio wave intensity required for communication of the determined type and information on the radio wave intensity.

12. The communication terminal according to claim 11, wherein:

[13] The network selection information storage means stores information relating to network security required for communication,

12. The communication terminal according to claim 11, wherein:

[14] The network selection information storage means stores the information related to security in association with information related to a terminal of a communication partner,

The network selection means extracts information related to security required for communication with a communication partner terminal, the network selection information storage means, and selects a network based on the extracted information related to security.

14. The communication terminal according to claim 13, wherein:

[15] The network selection information storage means stores the information regarding the security for each communication type,

The network selection means determines a communication type during data communication, extracts information related to security required for communication of the determined type from the network selection information storage means, and, based on the extracted information related to security! 14. The communication terminal according to claim 13, wherein a network is selected.

[16] The network selection information storage means stores information on the priority of a plurality of selection criteria for selecting the network,

The network selection means selects the network by applying the selection criterion in descending order of priority stored in the network selection information storage means. 12. The communication terminal according to claim 11, wherein:

A communication terminal capable of performing communication through a plurality of networks having different communication schemes, and a network control device that controls connection of the communication terminal to the network.

Lower layer information collecting means for detecting the intensity of radio waves received through at least one of the plurality of networks;

A detecting unit that detects, by using the radio wave intensity detected by the lower layer information collecting unit, that the mobile terminal has entered a network different from the network that is performing data communication with the partner terminal; Registration request transmission means for transmitting a registration request for registering that the communication terminal is a terminal connected to the network when detecting that the communication terminal has entered,

With

The network control device,

Registration request receiving means for receiving the registration request transmitted from the communication terminal; a destination table created based on the registration request received by the registration request receiving means;

A network system comprising: [18] A method in which a network control device that controls connection to a communication terminal connectable to a plurality of networks having different communication methods selects a network to be connected to the communication terminal,

A registration request receiving step of receiving from the communication terminal a registration request for registering that the communication terminal is a terminal connected to a network,

Creating a destination table based on the received registration request in the registration request receiving step;

A transfer step of transferring data to the communication terminal with reference to the destination table; and a registration request to the another network indicating that the communication terminal has entered a network different from the network in which data communication is being performed. A network selecting step for selecting a network to be used for transferring data to the communication terminal based on the information in which the communication terminal has been registered in advance to select one network when receiving the network; A table updating step of updating the destination table so as to transfer data through the network selected in the step;

A network selection method, comprising:

[19] A method of controlling a connection to a communication terminal connectable to a plurality of networks having different communication methods, a method of selecting a network used for communication by a communication terminal connected to a network control device,

A detection step of detecting that the user has entered a network different from the network that is performing data communication with the partner terminal;

A network selection step of selecting a network to be used for receiving data based on information for selecting one network registered in advance when detecting that the network has entered another network in the detection step; When,

The destination table of the network control device, which is updated based on a registration request for registering that the communication terminal is a terminal connected to the network and is referred to when the network control device transmits data, An update message transmitting step of transmitting to the network control device an update message for updating to receive data through the selected network in the network selection step; When,

A network selection method, comprising: