JP2012054930A - Mag, lma, system, and high-speed handover method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile access gateway, a local mobility anchor, a system, and a high-speed handover method of the same which are capable of reducing wasteful network resources by reducing excess tunnels.SOLUTION: When the mobile access gateway communicates with a mobile terminal or the like and detects that the mobile terminal is trying to handover to one of the other mobile access gateways, the mobile access gateway transmits a message of handover start (HI)(S103). After receiving a message of handover confirmation (HAck)(S105), the mobile access gateway checks whether a tunnel for the mobile terminal is established (S107) between the one of the other mobile access gateways and the mobile access gateway. If established, the mobile access gateway deletes the tunnel (S113) and establishes a tunnel for the mobile terminal (S115).

Description

  The present invention relates to a mobile access gateway, a local mobility anchor, a proxy mobile IPv6 system, and a fast handover method thereof, and more particularly to a mobile access gateway, a local mobility anchor, and a system that realize fast handover around a plurality of cells of a mobile terminal in the proxy mobile IPv6 system. And a fast handover method thereof.

  Proxy Mobile IPv6 (Proxy Mobile IPv6 (PMIPv6) (RFC 5213)) is a network-based mobile management protocol, in which IP movement can be realized even if the mobile terminal does not participate in transmission of any signaling related to movement. . The network side manages the IP movement of the mobile terminal. The mobile proxy in the network transmits mobile signaling to the home agent instead of the mobile terminal, and manages the movement of the mobile terminal. In the Proxy Mobile IPv6 protocol, a local mobility anchor (Local Mobility Anchor (LMA)) and a mobile access gateway (Mobile Access Gateway (MAG)) establish a bidirectional tunnel and transfer data for each mobile terminal. To do. The proxy mobile IPv6 protocol is used in multiple wide area wireless networks such as 3GPP, 3GPP2, and WiMAX, and in local wireless network environments.

  Further, in the proxy mobile IPv6 fast handover protocol (Fast Handovers for Proxy Mobile IPv6, draft-ietf-mishop-pfmipv6-13.txt), the handover delay when a mobile terminal performs handover between different access networks in proxy mobile IPv6 A method of decreasing has been proposed. When the mobile terminal moves from the old MAG to the new MAG network, before the new MAG completes the binding registration of the mobile terminal to the LMA, data is established by establishing a bidirectional tunnel between the old MAG and the new MAG. Transfer to the mobile terminal.

  However, when a mobile terminal is handed over around a plurality of MAG access networks, the movement prediction may fail. That is, at first, the mobile terminal is predicted to be handed over to the new MAG, and a bidirectional tunnel is established between the old MAG and the new MAG. However, the mobile terminal performs a fast handover to another new MAG, and the old MAG and the other MAG. A bidirectional tunnel is also established between the new MAGs. In this case, the bidirectional tunnel established between the old MAG and the other new MAG is used, but the bidirectional tunnel established between the new MAG is not used. There is a problem of forming, and therefore, network resources are wasted.

  The present invention has been made to solve the above-described problems. A mobile access gateway, a local mobility anchor, a proxy mobile IPv6 system, and a fast handover method thereof that can reduce unnecessary tunnels and reduce waste of network resources. The purpose is to provide.

  To achieve the above object, one technical solution according to the present invention is a mobile access gateway that communicates with a mobile terminal and a plurality of other mobile access gateways, a network interface that transmits and receives messages, and a handover start message. And a handover confirmation message processing unit for processing the received handover confirmation message, and the mobile terminal performs handover to one mobile access gateway among the plurality of other mobile access gateways. If it detects that an attempt is made, the handover start message configuration unit configures a handover start message, and sends the configured handover start message via the network interface. After transmitting to one mobile access gateway and receiving a handover confirmation message from the one mobile access gateway via the network interface, the handover confirmation message processing unit is other than the mobile access gateway and the one mobile access gateway. Check whether a tunnel for the mobile terminal has been established with another mobile access gateway, and if the tunnel has already been established, delete the tunnel, and A tunnel for the mobile terminal is established between the one mobile access gateway.

  Another technical solution according to the present invention is a local mobility anchor that communicates with a plurality of mobile access gateways, and includes a network interface that transmits and receives a message, and a HOF message processing unit that processes a received handover completion message. A mobile terminal from one mobile access gateway in a plurality of mobile access gateways via the network interface between the one mobile access gateway and another mobile access gateway in the plurality of mobile access gateways. The HOF message processing unit receives the one other mobile access gateway and the one mobile when receiving a handover complete message indicating that a tunnel for the communication has been established Check whether a tunnel for the mobile terminal, that is, an extra tunnel has already been established with a plurality of mobile access gateways other than the access gateway, and if an extra tunnel has already been established, A tunnel deletion message for deleting the extra tunnel is constructed and transmitted to the corresponding mobile access gateway. "

  Another technical solution according to the present invention is a proxy mobile IPv6 system including a local mobility anchor that communicates via a network, a plurality of mobile access gateways, and a mobile terminal. It is characterized by being a mobile access gateway.

  Another technical solution according to the present invention is a fast handover method of a mobile access gateway that communicates with a mobile terminal and a plurality of other mobile access gateways, wherein the mobile terminal is one of the plurality of other mobile access gateways. When it is detected that a handover to a mobile access gateway is attempted, a handover start message is configured, and the configured handover start message is transmitted to the one mobile access gateway via the network interface. After receiving a handover confirmation message from the one mobile access gateway, the mobile access gateway and another mobile access gateway other than the one mobile access gateway Whether or not a tunnel for the mobile terminal has already been established between the mobile access gateway and the mobile access gateway and the one access point. A tunnel for the mobile terminal is established between mobile access gateways.

  Another technical solution according to the present invention is a fast handover method of a mobile access gateway that communicates with a local mobility anchor and a plurality of mobile access gateways, wherein the local mobility anchor is one mobile access in the plurality of mobile access gateways. A handover complete message is received from the gateway indicating that a tunnel for the mobile terminal has already been established between the one mobile access gateway and another one of the mobile access gateways. A tunnel for the mobile terminal between the other one mobile access gateway and a plurality of mobile access gateways other than the one mobile access gateway, i.e., an extra Check whether a tunnel has already been established, and if an extra tunnel has already been established, construct a tunnel delete message indicating the deletion of the extra tunnel and send it to the corresponding mobile access gateway It is characterized by that.

  According to the present invention, when the old MAG detects that the mobile terminal is about to hand over to the new MAG network, the old MAG sends a handover start message to the new MAG, and the new MAG returns a handover confirmation message. After the old MAG receives the HAck message, it first checks whether a tunnel for the mobile terminal has already been established. If the tunnel has already been established, the tunnel is deleted and the new MAG Establish a tunnel. For this reason, when a mobile terminal hands over between a plurality of MAG networks, establishment of an extra tunnel due to a failure of movement prediction can be prevented, and waste of network resources can be reduced.

1 is a layout diagram showing a proxy mobile IPv6 system in which a mobile terminal of the present invention can perform high-speed handover in a MAG access network. It is a block diagram which shows the structure of MAG of this invention. It is a figure which shows the tunnel recording database in MAG of this invention. It is a figure which shows the format of the handover start (HI) message of this invention. It is a figure which shows the format of the hand-over confirmation (HAck) message of this invention. It is a flowchart which shows the process of the hand-over confirmation (HAck) message by MAG of this invention. It is a signaling flowchart which shows the control of the fast handover by MAG of this invention. It is a block diagram which shows the structure of LMA of this invention. It is a figure which shows the multicast handover recording database in LMA of this invention. It is a figure which shows the format of the handover notification (HON) message of this invention, and a handover completion (HOF) message. It is a figure which shows the format of the tunnel deletion (TD) message of this invention. It is a signaling flowchart which shows the control of the fast handover by LMA of this invention. FIG. 2 is a layout diagram of a system for controlling high-speed handover by LMA using the signal strength of a base station according to the present invention. It is a block diagram which shows the structure of LMA which controls a fast handover using the signal strength of the base station of this invention. It is a figure which shows the multicast handover recording database in LMA which controls a fast handover using the signal strength of the base station of this invention. It is a figure which shows the format of a handover start (HI) message when controlling the fast handover using the signal strength of the base station of the present invention. FIG. 5 is a diagram illustrating a format of a handover notification (HON) message / handover completion (HOF) message when controlling fast handover using the signal strength of the base station of the present invention. It is a figure which shows the format of the network status message when controlling the fast handover using the signal strength of the base station of the present invention. 3 is a signaling flowchart illustrating a network state when controlling fast handover using the signal strength of a base station according to the present invention. It is a flowchart which shows the process of the network status message by LMA of this invention. 5 is a signaling flowchart for controlling high-speed handover by LMA using the signal strength of the base station of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are merely examples for explaining the contents of the present invention, and do not limit the present invention.
<Structure of proxy mobile IPv6 system>

  First, the proxy mobile IPv6 system of the present invention will be described with reference to FIG. FIG. 1 is a layout diagram showing a proxy mobile IPv6 system in which a mobile terminal of the present invention can perform high-speed handover in a MAG access network.

  As shown in FIG. 1, the system includes mobile access gateways (abbreviated as “MAG”) MAG11, MAG12, MAG13, local mobility anchor (abbreviated as “LMA”) 2, core network (network) 3, and mobile terminals ( (Abbreviated as “MN”) (mobile terminal) 4. Among them, the proxy mobile IPv6 protocol can be referred to for the definition of the mobile access gateway, the local mobility anchor, the mobile terminal, etc., and the description thereof is omitted here.

  MAG11, MAG12, and MAG13 perform downlink access to the mobile terminal 4, and communicate with the mobile terminal 4 and other MAGs other than itself through the network. The MAG manages the IP movement of the mobile terminal 4 and transmits signaling related to movement on behalf of the mobile terminal 4, and the mobile terminal 4 is not involved in transmission of signaling related to movement. The LMA 2 accesses the MAG 11, MAG 12, and MAG 13 in the downlink, is a home agent of the mobile terminal 4, and connects to each other via the core network 3.

  As shown by a dotted line in FIG. 1, when the mobile terminal 4 moves from the network cover range of the MAG 11 to the network cover range of the MAG 12, and then moves to the network cover range of the MAG 13 again, the MAG 11 (hereinafter referred to as “old MAG”). ) And MAG 12 or MAG 13 (hereinafter, the handover destination MAG is referred to as “new MAG” or “target MAG”), and the data is transferred for the mobile terminal 4.

<Structure of mobile access gateway MAG>
In the present embodiment, the MAG is improved and the function of the MAG is expanded. Hereinafter, the structure of the mobile access gateway MAG of the present invention will be described with reference to FIG. 2A. FIG. 2A is a block diagram showing the structure of the MAG of the present invention.

  As shown in FIG. 2A, the mobile access gateway MAG includes a network interface 10, an HI (Handover Initiate) message processing unit 14, a storage unit 15, an HI message configuration module 16, a bus 17, HAck (Handover Acknowledgment). A message processing unit 18 and a control unit 19 are included.

  The network interface 10 communicates with an external device (LMA, other MAG, MN, etc.), and transmits and receives various messages. The network interface 10 includes an HI / HAck message receiving module 101 and an HI / HAck message transmitting module 103. The HI / HAck message receiving module 101 receives HI messages and HAck messages transmitted from the outside. The HI / HAck message transmission module 103 transmits an HI message and a HAck message. The format of the HI message and the HAck message will be described in detail later with reference to FIGS. 3A and 3B.

  The HI message processing unit 14 processes the HI message received from the outside via the HI / HAck message receiving module 101 of the network interface 10, calls the HAck message configuration module 141 of the HI message processing unit 14, and returns it to the HI message. After that, the HAck message configured via the HI / HAck message transmission module 103 of the network interface 10 is transmitted to the outside.

  The storage unit 15 includes a memory device such as a hard disk, a flash card, a ROM, or a RAM, in which a multicast handover database 151 is stored, and the multicast handover database 151 stores the received multicast handover message message A recording table 1511 is stored. The specific contents of the multicast handover record table 1511 will be described in detail later with reference to FIG. 2B.

  The HI message configuration unit 16 configures an HI message. For example, when the mobile terminal 4 moves from the network coverage area of the MAG 11 to the network coverage area of the MAG 12, the mobile access gateway MAG 11 detects that the mobile terminal 4 is about to be handed over from the MAG 11 (old MAG) to the MAG 12 (new MAG). After that, the HI message configuration unit 16 configures the HI message and transmits the configured HI message to the MAG 12 via the HI / HAck message transmission module 103 of the network interface 10.

  The bus 17 transmits data between MAG units and modules.

  The HAck message processing unit 18 processes the HAck message received via the HI / HAck message receiving module 101 of the network interface 10. When the HAck message processing unit 18 processes the HAck message, it first checks whether a tunnel for the mobile terminal in the HAck message has already been established. When it is detected that a tunnel has been established, the tunnel is deleted, and then a tunnel from the old MAG to the new MAG is configured. When it is detected that the tunnel has not been established, the tunnel from the old MAG to the new MAG is directly configured. The HAck message processing unit 18 is a tunnel check module 181 that checks whether a tunnel for the mobile terminal 4 has already been established, a tunnel deletion module 181 that deletes an established extra tunnel, and a tunnel configuration that forms a new tunnel. It includes a plurality of modules such as module 185. An example in which the HAck message processing unit 18 composed of a plurality of modules processes the HAck message will be described in detail later with reference to FIG.

  The control unit 19 controls each unit and module of the MAG. Specifically, when it is detected that the mobile terminal 4 is about to handover from the old MAG to the new MAG, or when a handover start message (for example, the HO Initiate message shown in FIG. 5) is received, the control unit 19 The HI message composing unit 16 is called to compose the HI message, and the network interface 10 is called to send the HI message to the new MAG. When receiving an HI message from the outside via the network interface 10, the control unit 19 calls the HI message processing unit 14, processes the HI message, and configures an HAck message to be returned to the HI message. When the HAck message is received via the network interface 10, the HAck message processing unit 18 is called to process the HAck message.

  The tunnel recording table 1511 stored in the tunnel recording database 151 in the MAG shown in FIG. 2A will be described in detail below with reference to FIG. 2B. FIG. 2B is a diagram showing a tunnel record database in the MAG of the present invention.

  As shown in FIG. 2B, a tunnel record table 1511 is stored in the tunnel record database 151. The tunnel record table 1511 includes fields such as a sequence number 15111, an MN address 15113, a destination address 15115, and an effective period 15117. It is included. Of these, the sequence number 15111 is the sequence number in the database of the record, the MN address 15113 is the address of the mobile terminal 4, the destination address 15115 is the address of the new MAG handed over by the mobile terminal 4, and the valid period 15117 is the valid time of the record. Each is shown.

  Next, the format of the HI message and the HAck message will be described in detail with reference to FIGS. 3A and 3B. FIG. 3A is a diagram showing the format of the HI message of the present invention, and FIG. 3B is a diagram showing the format of the HAck message of the present invention.

  As shown in FIG. 3A, M100 is a format of the HI message and includes fields such as a transmission source M101, a destination address M102, a type M104, a length M106, and a mobile terminal address M108. The source M101 indicates the address of the MAG that transmitted the message, the destination address M102 indicates the address of the destination that transmits the message, and the type M104 indicates the type of the message. The type of message here is an HI message. The length M106 indicates the length of the message, and the mobile terminal address M108 records the address of the mobile terminal of the MAG that is the handover destination.

  As shown in FIG. 3B, M200 is the format of the HAck message and includes fields such as a source address M201, a destination address M202, a type M204, a length M206, and a mobile terminal address M208. Among them, the source address M201 indicates the address of the MAG constituting the message, the destination address M202 indicates the address of the destination to which the message is transmitted, and the type M204 indicates the type of the message. The message type here is a HAck message. The length M206 indicates the length of the message, and the mobile terminal address M208 is a copy of the mobile terminal address M108 in the transmitted HI message.

  Hereinafter, an example of the processing process of the HAck message when the mobile terminal hands over the MAG will be described with reference to FIG. FIG. 4 is a flowchart showing the processing of the HAck message by the MAG of the present invention.

  As shown in FIG. 4, the MAG HI / HAck message receiving module 101 periodically receives various messages repeatedly (step F101). After the HI / HAck message receiving module 101 receives the HAck message (step F102), the HAck message processing unit 18 starts processing the HAck message. First, the mobile terminal address in the HAck message is extracted, and then the tunnel check module 181 determines whether a tunnel for the mobile terminal has already been established between the old MAG and another MAG other than the new MAG. Is checked (step F103). When the tunnel check module 181 detects that the tunnel has already been established, the tunnel deletion module 183 deletes the tunnel (step F104). Thereafter, the tunnel configuration module 185 establishes a tunnel from the old MAG to the new MAG for the mobile terminal. When the tunnel check module 181 detects that the tunnel has not been established, the tunnel configuration module 185 directly establishes a tunnel from the old MAG to the new MAG (step F106).

  Hereinafter, a specific process of the MAG when the mobile terminal of the present invention performs high-speed handover of the MAG will be described with reference to FIG. FIG. 5 is a signaling flowchart showing the fast handover control by the MAG of the present invention.

  As shown in FIG. 5, first, the mobile terminal 4 transmits and receives data via the old MAG (S101).

  When the mobile terminal 4 detects that it intends to move from the network cover range of the MAG 11 that is the old MAG to the network cover range of the MAG 12 that is the new MAG, the mobile terminal 4 starts the handover including the address information of the new MAG 12 ( A HOInitiate message is transmitted to the old MAG 11 (S102).

  After the old MAG 11 receives the handover start message, the HI message configuration unit 16 of the old MAG 11 configures the HI message and transmits the HI message including the address information of the mobile terminal 4 to the new MAG 12 (S103). ).

  After the new MAG 12 receives the HI message from the old MAG 11 via the HI / HAck message receiving module 101, the HI message processing unit 14 processes the HI message, and the HAck message structure module 141 sends back the HA message to the HI message. The message is composed, and then the HAck message is returned to the old MAG 11 via the HI / HAck message transmission module 103 (S105).

  After the old MAG 11 receives the HAck message returned from the new MAG 12 via the HI / HAck message receiving module 101, the tunnel check module 181 determines whether the mobile terminal 4 is connected between the old MAG 11 and another MAG (here, MAG 13). Check whether the tunnel for the connection has already been established. In this case, since the tunnel has not been established, the tunnel configuration module 185 directly establishes a tunnel from the old MAG 11 to the new MAG 12 (S107). As described above, the mobile terminal 4 can continue to transmit data through the tunnel between the old MAG 11 and the new MAG 12 after handover to the new MAG 12.

  Next, when it is detected that the mobile terminal 4 is going to move from the network cover range of the MAG 12 to the network cover range of the MAG 13 again, at this time, the MAG 13 is the new MAG and the mobile terminal 4 contains the address of the new MAG 13. A handover start message is transmitted to the old MAG 11 (S109).

  When the old MAG 11 receives a handover start message indicating that it wants to hand over to the new MAG 13 of the mobile terminal 4, the HI message configuration unit 16 of the old MAG 11 configures the HI message and includes the address information of the mobile terminal 4. The existing HI message is transmitted to the new MAG 13 (S110).

  After the new MAG 13 receives the HI message from the old MAG 11 via the HI / HAck message receiving module 101, the HI message processing unit 14 processes the HI message, and the HAck message configuration module 141 returns the HAck to the HI message. The message is composed, and then the HAck message is returned to the old MAG 11 via the HI / HAck message transmission module 103 (S111).

  After the old MAG 11 receives the HAck message returned from the new MAG 13 via the HI / HAck message receiving module 101, the tunnel check module 181 determines that the mobile terminal between the old MAG 11 and another MAG (here, MAG 12). It is checked whether a tunnel for 4, that is, an extra tunnel has already been established (S 113). In this case, since it is detected that a tunnel for the mobile terminal 4 has already been established between the old MAG 11 and the MAG 12, the tunnel deletion module 183 deletes the tunnel from the old MAG 11 to the MAG 12 (S113). The tunnel configuration module 185 newly establishes a tunnel from the old MAG 11 to MAG 13 (S115).

  After the mobile terminal 4 is handed over to the new MAG 13 network, data transmission can be continued through the tunnel between the old MAG 11 and the new MAG 13 (S117).

In this way, high-speed handover can be realized even when a mobile terminal moves between a plurality of MAG networks (high-speed handover), and at the same time, establishment of an extra tunnel due to failure of movement prediction is prevented, and network resources are wasted Can be reduced.
<Structure of local mobility anchor LMA>

  In this embodiment, the local mobility anchor LMA is improved and its function is expanded. Hereinafter, the structure of the LMA of the present invention will be described with reference to FIG. 6A. FIG. 6A is a block diagram showing the configuration of the LMA of the present invention.

  As shown in FIG. 6A, the LMA 2 includes a network interface 20, a HON (Handover Notification) message processing unit 24, a storage unit 25, a HOF (Handover Complete: Handover Finish) message processing unit 26, a bus 27, and a control unit 29. including.

  The network interface 20 transmits and receives various messages, and includes a HON / HOF message reception module 201 and a TD (tunnel delete) message transmission module 203. The HON / HOF message receiving module 201 receives a HON message for notifying an external handover and a HOF message indicating that the handover is completed. The TD message transmission module 203 transmits a TD message indicating that an extra tunnel has been deleted. The format of the HON message, the HOF message, and the TD message will be described in detail later with reference to FIGS. 7A and 7B.

  The HON message processing unit 24 processes the HON message received via the network interface 20 and, when processing, processes information related to the multicast handover received by calling the multicast handover recording module 241 included in the HON message processing unit 24. Record.

  The storage unit 25 includes a memory device such as a hard disk, a flash card, a ROM, or a RAM. A multicast handover database 251 is stored in the storage unit 25, and the received multicast handover message is received in the multicast handover database 251. A recorded multicast handover record table 2511 is stored. The specific contents of the multicast handover record table 2511 will be described in detail later with reference to FIG. 6B.

  The HOF message processing unit 26 processes the HOF message received via the network interface 20 and includes a multicast handover check module 261, a TD message configuration module 263, and a multicast handover record update module 265. When processing the HOF message, the multicast handover check module 261 checks whether the multicast handover record for the mobile terminal in the plurality of HOF messages is stored in the multicast handover database 251. When there are a plurality of records, the TD message configuration module 263 is called to configure the TD message, and then the TD message is transmitted to the related MAG via the TD message transmission module 203. Thereafter, the multicast handover record update module 265 is called to update the multicast handover record of the mobile terminal in the multicast handover database 251.

  The control unit 29 controls each unit and module of the LMA.

  Hereinafter, the multicast handover record table 2511 stored in the multicast handover record database 251 in the LMA illustrated in FIG. 6A will be described in detail with reference to FIG. 6B. FIG. 6B is a diagram showing a multicast handover record database in the LMA of the present invention.

  As shown in FIG. 6B, a multicast handover record table 2511 is recorded in the multicast handover record database 251. The multicast handover record table 2511 includes a sequence number 25111, an MN address 25113, a new MAG address 25115, a multicast address 25117, an old MAG address 25119, and a status flag 25121. Among them, the sequence number 25111 is the sequence number in the multicast handover record database 251 of the record, the MN address 25113 is the address of the mobile terminal to be handed over, the new MAG address 25115 is the address of the new MAG, and the multicast address 25117 is joined to the mobile terminal. Multicast group, old MAG address 25119 indicates the address of the old MAG, and status flag 25121 indicates whether the type of received handover notification is HON or HOF.

  Next, the format of the HON message, the HOF message, and the TD message will be described in detail with reference to FIGS. 7A and 7B. FIG. 7A is a diagram showing the format of the HON message and HOF message of the present invention, and FIG. 7B is a diagram showing the format of the TD message of the present invention.

  As shown in FIG. 7A, M400 is a format of a HON message and a HOF message. The source address M401, the destination address M402, the type M404, the length M406, the MN address M408, the multicast address M410, the old MAG address 412, and the status It includes a field such as flag M414. Among them, the source address M401 is the address of the new MAG, the destination address M402 is the address of the LMA, the type M404 is a multicast handover message including the message type HON and HOF, and the length M406 is the length of the message , The MN address M408 is the address of the mobile terminal to be handed over, the multicast address M410 is the address of the multicast group to which the mobile terminal to be handed over has joined, the old MAG address 412 is the address of the old MAG before the handover, and the status flag M414 indicates the handover state of the mobile terminal. When the status flag M414 is “0”, it indicates that a handover is to be performed, the message type is a HON message, and when the status flag M414 is “1”, the handover is completed and the message type is a HOF message. Indicates.

  As shown in FIG. 7B, M600 is a format of a TD message, and includes a source address M601, a destination address M602, a type M604, a length M606, a MN address M610, a multicast address M612, and an old MAG address 614. Of these, the source address M601 is the LMA address, the destination address M602 is the new MAG address, the type M604 is the message type is a TD message, the length M606 is the length of the message, and the MN address M610 is the mobile terminal , Multicast address M612 indicates the address of the multicast group to which the mobile terminal is subscribed, and old MAG address 614 indicates the address of the MAG before the handover.

  Hereinafter, a specific process of the fast handover by the LMA of the present invention will be described with reference to FIG. FIG. 8 is a signaling flowchart showing the fast handover control by the LMA of the present invention.

  As shown in FIG. 8, first, the mobile terminal 4 is connected to the old MAG 11 and receives and transmits data via the old MAG 11 (S201).

  When the mobile terminal 4 detects that it intends to move from the coverage area of the old MAG11 network to the coverage area of the new MAG12 network, the mobile terminal 4 sends an old handover start (HO Initiate) message including the address information of the target MAG12. It transmits to MAG11 (S202). After receiving the handover start message, the old MAG 11 transmits HI information including the address of the mobile terminal 4 and multicast group information to the new MAG 12 (S203). After receiving the HI message, the new MAG 12 returns a HAck message to the old MAG 11 (S205), and simultaneously transmits a HON (handover notification) message to the LMA 2 (S206), so that the mobile terminal 4 is handed over to the MAG 12 network. To LMA2. After the HON / HOF message receiving module 201 of the LMA 2 receives the HON message from the MAG 12, the multicast handover recording module 241 stores the multicast handover information included in the HON message in the multicast handover recording table 2511 in the multicast handover database 251. Record. The old MAG 11 establishes a tunnel from the old MAG 11 to the new MAG 12 for the mobile terminal 4 after receiving the HAck message transmitted from the new MAG 12 (S207).

  Next, since the mobile terminal 4 has also detected that it is going to be handed over to the MAG 13, it transmits a handover start message to the old MAG 11 (S209). The old MAG 11 transmits an HI message to the new MAG 13 (S210). After receiving the HI message, the new MAG 13 returns a HAck message to the MAG 11 (S211), and simultaneously transmits a HON message to the LMA 2 (S213). The multicast handover recording module 241 of the LMA 2 records the multicast handover information included in the HON message from the MAG 13 received via the HON / HOF message receiving module 201 in the multicast handover recording table 2511 in the multicast handover database 251. After receiving the HAck message, the old MAG 11 establishes a tunnel from the old MAG 11 to the new MAG 13 for the mobile terminal 4 (S214).

  After that, since the mobile terminal 4 detects that it is going to hand over to the MAG 14 again, it transmits a handover start message to the old MAG 11 (S215). The old MAG 11 transmits an HI message to the new MAG 14 (S216). After receiving the HI message, the new MAG 14 returns a HAck message to the MAG 11 (S217), and simultaneously transmits a HON message to the LMA 2 (S218). The multicast handover recording module 241 of the LMA 2 records the multicast handover information included in the HON message from the MAG 14 received via the HON / HOF message receiving module 201 in the multicast handover recording table 2511 in the multicast handover database 251. After receiving the HAck message, the old MAG 11 establishes a tunnel from the old MAG 11 to the new MAG 14 for the mobile terminal 4 (S219).

  After the mobile terminal 4 connects to the new MAG 14, the MAG 14 transmits a HOF message to the LMA 2 (S220) to notify the mobile terminal 4 that the handover has been completed. After the HON / HOF message reception module 201 of the network interface 20 of the LMA 2 receives the HOF message, the multicast handover check module 261 of the HOF message processing unit 26 stores the multicast handover related to the mobile terminal in the plurality of HOF messages in the multicast handover database 251. Check if the record is stored. That is, it is checked whether there is an extra tunnel. In this case, since there are three tunnels from MAG11 to MAG12, from MAG11 to MAG13, and from MAG11 to MAG14, the TD message composition module 263 deletes two extra tunnels from MAG11 to MAG12 and from MAG11 to MAG13. TD message is transmitted to the MAG 13 (S221), and at the same time, the TD message is transmitted to the MAG 12 (S222) to notify the related MAGs to delete the extra tunnels. Thereafter, the multicast handover record update module 265 updates the multicast handover record of the mobile terminal 4 in the multicast handover database 251.

As described above, the mobile terminal 4 transmits and receives data through a tunnel established between the old MAG 11 and the new MAG 14. The mobile terminal 4 can realize high-speed handover even when moving between a plurality of MAG networks at high speed, prevent establishment of an extra tunnel due to failure of movement prediction, and reduce waste of network resources.
<Structure of proxy mobile IPv6 system with signal strength report>

  First, another example of the proxy mobile IPv6 system of the present invention will be described with reference to FIG. FIG. 9 is a layout diagram of a system for controlling high-speed handover by LMA using the signal strength of the base station of the present invention.

  As shown in FIG. 9, the system includes MAG11, MAG12, MAG13, LMA32, core network 3, mobile terminal 4, and base stations 51, 52, 53. Since details of the mobile access gateway MAG, the local mobility anchor LMA, the definition of the mobile terminal MN, and the like can be referred to, the proxy mobile IPv6 protocol can be referred to, so the description thereof is omitted here.

MAG11, MAG12, and MAG13 access the mobile terminal 4 through base stations 51, 52, and 53, respectively, and communicate with the mobile terminal 4, the base station, and other MAGs other than themselves through the network. Although the MAG manages the IP movement of the mobile terminal 4 and transmits signaling related to movement instead of the mobile terminal 4, the mobile terminal 4 is not involved in transmission of signaling related to movement. The LMA 32 has downlink access to the MAG 11, MAG 12, and MAG 13, is a home agent of the mobile terminal 4, and connects to each other via the core network 3.
<Structure of local mobility anchor LMA with signal strength report>

  In the present invention, the local mobility anchor LMA is improved and its function is expanded. Hereinafter, the structure of the LMA with a signal strength report of the present invention will be described with reference to FIG. 10A. FIG. 10A is a block diagram showing a configuration of an LMA that controls fast handover using the signal strength of the base station of the present invention.

  As shown in FIG. 10A, the LMA 32 includes a network interface 30, a HON message processing unit 24, a storage unit 35, a HOF message processing unit 26, a bus 27, a control unit 29, and a network status message processing unit 38. Compared with FIG. 6A, since the HON message processing unit 24, the HOF message processing unit 26, and the bus 27 are substantially the same, description of these units is omitted here.

  The network interface 30 includes a HON / HOF message reception module 201, a TD message transmission module 203, and a network status message reception module 305. Similar to FIG. 6A, the HON / HOF message reception module 201 receives HON and HOF messages from the outside, and the TD message transmission module 203 transmits an unnecessary tunnel deletion message. The network status message receiving module 305 receives a network status message representing a network status from the outside. The format of the HI message, HON message, HOF message, and network status message will be described in detail later with reference to FIGS. 11A to 11C.

  The storage unit 35 includes memory devices such as a hard disk, a flash card, a ROM, and a RAM. A multicast handover database 351 is stored in the storage unit 35, and the received multicast handover message is received in the multicast handover database 351. A recorded multicast handover record table 35111 is stored. Specific contents regarding the multicast handover record table 35111 will be described in detail later with reference to FIG. 10B.

  The network status message processing unit 38 processes the network status message received via the network status message receiving module 305, checks information on the signal strength included in the network status message, and the signal strength is a predetermined threshold value. If lower, the TD message composition module 263 composes a TD message and sends the TD message to the associated MAG via the TD message transmission module 203.

  Hereinafter, the multicast handover record database 351 in the LMA shown in FIG. 10A will be described in detail with reference to FIG. 10B. FIG. 10B is a diagram showing a multicast handover record database in the LMA that controls fast handover using the signal strength of the base station of the present invention.

  As shown in FIG. 10B, a multicast handover table 3511 is stored in the multicast handover record database 351. The multicast handover table 3511 includes a sequence number 25111, an MN address 23113, a new MAG address 25115, a multicast address 25117, and an old MAG address 25119. , Status flag 25121, and signal strength 25123. Compared with the field included in the multicast handover table 2511 of FIG. 6B, the signal strength 25123 is increased. The signal strength 25123 indicates the signal strength of the base station detected by the mobile terminal.

  Next, the format of the HI message, HON message, HOF message, and network status message will be described in detail with reference to FIGS. 11A to 11C. FIG. 11A is a diagram showing a format of an HI message when fast handover is controlled using the signal strength of the base station of the present invention. FIG. 11B is a diagram showing a format of a HON message / HOF message when the fast handover is controlled using the signal strength of the base station of the present invention. FIG. 11C is a diagram illustrating a format of a network status message when the fast handover is controlled using the signal strength of the base station according to the present invention.

  As shown in FIG. 11A, M1100 is the format of the HI message, and the signal strength M109 is increased as compared to the format M100 of the HI message shown in FIG. 3A. The signal strength M109 records the signal strength of the base station detected by the mobile terminal 4.

  As shown in FIG. 11B, M1400 indicates the format of the HON / HOF message, and the signal strength M415 is increased as compared with the format M400 of the HON / HOF message shown in FIG. 7A. The signal strength M415 records the signal strength of the base station detected by the mobile terminal 4.

  As shown in FIG. 11C, M500 is a network status message format, and includes a source address M501, a destination address M502, a type M504, a length M506, a MN address M508, and a signal strength M509. Among them, the source address M501 is the source address, the destination address M502 is the address on the receiving side, the type M504 is that the type of the message is a network status message, the length M506 is the length of the message, and the MN address M508. Indicates the address of the mobile terminal, and the signal strength M509 records the signal strength of the base station detected by the mobile terminal.

  Next, the transmission status in the system of the network status message with the signal strength report will be described with reference to FIG. FIG. 12 is a signaling flowchart showing a network state when the fast handover is controlled using the signal strength of the base station of the present invention.

  As shown in FIG. 12, when the mobile terminal 4 sends a network status message including the signal strength of the base station detected by the mobile terminal 4 to the MAG 11 and reports the current signal strength of the base station (S301), The MAG 11 transfers the network status message from the mobile terminal 4 to the LMA 32 (S302). When the mobile terminal 4 transmits a network status message to the new MAG 12 and reports the signal strength of the target base station (S303), the MAG 12 transfers the network status message from the mobile terminal 4 to the LMA 32 (S304).

  The process for processing network status messages by the LMA with signal strength reporting of the present invention will now be described with reference to FIG. FIG. 13 is a flowchart showing network status message processing by the LMA of the present invention.

  As shown in FIG. 13, the network status message receiving module 305 of the LMA 32 receives the message (F202), and after the network status message receiving module 305 receives the network status message (F203), the network status message processing unit 38 The message is processed, the signal strength of the base station detected by the mobile terminal is extracted from the message, and it is checked whether the signal strength is lower than a predetermined threshold (F204). If lower than the threshold, the TD message configuration module 263 configures the TD message, sends the TD message to the associated MAG (F204), and notifies the MAG to delete the tunnel established for the mobile terminal. .

  Hereinafter, a specific process of the fast handover by the LMA of the present invention will be described with reference to FIG. FIG. 14 is a signaling flowchart for controlling high-speed handover by LMA using the signal strength of the base station of the present invention.

  As shown in FIG. 14, the mobile terminal 4 is connected to the old MAG 11 and transmits / receives data via the old MAG 11 (S401). When it is detected that the mobile terminal 4 is about to move to the new MAG 12 network, a handover start message (HO Initiate) including the address information of the target MAG 12 is transmitted to the old MAG 11 (S402). After receiving the handover start message, the old MAG 11 transmits an HI message including the mobile terminal address information and multicast group information to the new MAG 12 (S403). After receiving the HI message, the new MAG 12 returns a HAck message to the old MAG 11 (S405), and simultaneously sends a HON (handover notification) message to the LMA 32 (S406), and the mobile terminal is handed over to the network of the MAG 12 at the LMA 32. Notify that you are going to try. After receiving the HAck message, the old MAG 11 establishes a tunnel to the new MAG (S407).

  After that, when it is detected that the mobile terminal 4 is going to be handed over to the MAG 13, a handover start message is transmitted to the old MAG 11 (S409). The old MAG 11 transmits an HI message to the new MAG 13 (S410). After receiving the HI message, the new MAG 13 returns a HAck message to the old MAG 11 (S411), and simultaneously transmits a HON message to the LMA 32 (S413). After receiving the HAck message, the old MAG 11 establishes a tunnel to the new MAG 13 (S414).

  Next, the mobile terminal 4 transmits a network status message to the MAG 11 (S415), and reports the detected signal strength of the base station. The MAG 11 transfers the network status message from the mobile terminal 4 to the LMA 32 (S416). After the network status message reception module 305 of the LMA 32 receives the network status message, the network status message processing unit 38 extracts the signal strength in the received network status message, and at this time, the signal strength is a predetermined threshold value. If lower is detected, the TD message configuration module 263 configures a TD message, sends the TD message to the MAG 12 (S417), notifies the MAG 11 to delete the tunnel between the MAG 11, and multicast handover. The record update module 265 updates the multicast handover record of the mobile terminal in the multicast handover database 351.

  Next, the mobile terminal 4 detects that a handover to the MAG 14 is attempted, and transmits a handover start message to the old MAG 11 (S418). The old MAG 11 transmits an HI message to the new MAG 14 (S419). After receiving the HI message, the new MAG 14 returns a HAck message to the old MAG 11 (S420), and simultaneously transmits a HON message to the LMA 32 (S421). After receiving the HAck message, the old MAG 11 establishes a tunnel to the new MAG 14 (S422).

  After the mobile terminal connects to the new MAG 14, the MAG 14 transmits a HOF message to the LMA 32 (S423) to notify the mobile terminal 4 that the handover has been completed. The LMA 32 checks the multicast handover record database 251, and since an extra tunnel is found, it sends a TD (tunnel delete) message to the MAG 13 (S424) to notify the extra tunnel to be deleted. 265 updates the multicast handover record of the mobile terminal in the multicast handover database 251. The mobile terminal 4 transmits and receives data via the new MAG 14.

  The embodiments according to the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications and extensions are made within the scope of the present invention, or the structure is deleted. And can be combined.

  For example, in the present embodiment, when a mobile terminal performs a fast handover between a plurality of MAGs, the MAG detects that the mobile terminal is about to perform a handover by a handover start message transmitted from the mobile terminal. However, the present invention is not limited to this, and a message indicating that the mobile terminal is to be handed over to the MAG may be transmitted to the MAG by the base station that communicates with the mobile terminal. Of course, the MAG may check whether the mobile terminal is handed over to the MAG by other known techniques.

  In the embodiment, the application example has been described in the IPv6 protocol. However, the present invention is not limited to this, and can be applied to various technologies such as IPv4.

  In addition, units such as the network interface 10, the HI message processing unit 14, and the HAck message processing unit 18 in the MAG shown in FIG. 2A are composed of modules having a plurality of single functions. However, the present invention is not limited to this. These units may be integrated into one module to realize various functions. The same applies to the LMA shown in FIGS. 6A and 10A.

  Further, a module that transmits and receives a network status message may be installed in the MAG corresponding to the LMA 32 shown in FIG. 10A.

  2A includes an HI / HAck message receiving module 101 and an HI / HAck message transmitting module 103, but of course the present invention is not limited to this, and the HAck message receiving module and the HI are used as necessary. Only the message transmission module, or the HI message reception module and the HAck message transmission module may be installed. The network interface 20 shown in FIGS. 6A and 10A may be installed similarly.

Claims (12)

A mobile access gateway for communicating with a mobile terminal and a plurality of other mobile access gateways,
A network interface for sending and receiving messages;
A handover start message constructing unit constituting a handover start message;
A handover confirmation message processing unit for processing the received handover confirmation message,
When detecting that the mobile terminal is going to perform handover to one mobile access gateway among the plurality of other mobile access gateways, the handover start message configuration unit configures a handover start message, via the network interface Sending the configured handover start message to the one mobile access gateway;
After receiving a handover confirmation message from the one mobile access gateway via the network interface, the handover confirmation message processing unit is configured to connect between the mobile access gateway and another mobile access gateway other than the one mobile access gateway. Whether or not a tunnel for the mobile terminal has been established. If a tunnel has already been established, the tunnel is deleted, and the tunnel is deleted between the mobile access gateway and the one mobile access gateway. A mobile access gateway characterized by establishing a tunnel for a mobile terminal. The mobile access gateway according to claim 1,
The mobile access gateway further includes a handover start message processing unit for processing the received handover start message,
The handover start message processing unit includes a handover confirmation message configuration module that configures a handover confirmation message,
When receiving a handover start message from the other mobile access gateway via the network interface, the control unit controls the handover confirmation message configuration module to configure a handover confirmation message, and sends the handover confirmation message via the network interface. And transmitting the configured handover confirmation message to the other mobile access gateway. The mobile access gateway according to claim 1,
The handover confirmation message processing unit
A tunnel check module that checks whether a tunnel for the mobile terminal has been established between the mobile access gateway and another mobile access gateway other than the one mobile access gateway;
A tunnel deletion module for deleting a tunnel detected by the tunnel check module;
A mobile access gateway comprising a tunnel configuration module for establishing a tunnel for the mobile terminal between the mobile access gateway and the one mobile access gateway. The mobile access gateway according to claim 1,
The network interface is
A handover start message transmission module for transmitting a handover start message;
A handover confirmation message for receiving a handover confirmation message;
Mobile access gateway characterized by including. The mobile access gateway according to any one of claims 1 to 4,
The network interface is
A handover start message receiving module for receiving a handover start message;
A handover confirmation message for transmitting a handover confirmation message;
A mobile access gateway further comprising: A local mobility anchor communicating with multiple mobile access gateways,
A network interface for sending and receiving messages;
A HOF message processing unit for processing the received handover completion message,
For a mobile terminal between the one mobile access gateway and one other mobile access gateway in the plurality of mobile access gateways from one mobile access gateway in the plurality of mobile access gateways via the network interface When the handover completion message indicating that the tunnel has already been established is received, the HOF message processing unit performs communication between the one other mobile access gateway and a plurality of mobile access gateways other than the one mobile access gateway. In the meantime, it is checked whether a tunnel for the mobile terminal, that is, an extra tunnel has already been established, and if an extra tunnel has already been established, the extra tunnel is deleted. You constitute a channel deletion message, the corresponding local mobility anchor and transmits to the mobile access gateway. The local mobility anchor according to claim 6, wherein
The local mobility anchor is
A handover notification message processing unit having a multicast handover recording module for processing the received handover notification message and recording multicast handover information included in the received handover notification message;
A storage unit for storing multicast handover information recorded in the multicast handover recording module,
The HOF message processing unit
Based on multicast handover information recorded in the handover recording module, a tunnel for the mobile terminal between the other one mobile access gateway and a plurality of mobile access gateways other than the one mobile access gateway, That is, a multicast handover check module that checks whether an extra tunnel has already been established,
A tunnel delete message configuration module that configures a tunnel delete message indicating that the extra tunnel is deleted;
A multicast handover record update module for updating multicast handover information stored in the storage unit;
A local mobility anchor characterized by comprising: The local mobility anchor according to claim 6, wherein
The local mobility anchor is
A network status message processing unit for processing a network status message including the received signal strength;
When the signal strength included in the network status message is lower than a predetermined value, the HOF message processing unit configures a tunnel deletion message indicating deletion of a tunnel in use and transmits the tunnel deletion message to a corresponding mobile access gateway. Feature local mobility anchor. A proxy mobile IPv6 system comprising a local mobility anchor for communicating over a network, a plurality of mobile access gateways, and a mobile terminal,
The proxy mobile IPv6 system, wherein the mobile access gateway is the mobile access gateway according to any one of claims 1 to 5. A proxy mobile IPv6 system comprising a local mobility anchor for communicating over a network, a plurality of mobile access gateways, and a mobile terminal,
9. The proxy mobile IPv6 system according to claim 6, wherein the local mobility anchor is a local mobility anchor according to claims 6 to 8, wherein the mobile access gateway has a handover notification message configuration unit that forms a handover notification message. A mobile access gateway fast handover method for communicating with a mobile terminal and a plurality of other mobile access gateways, comprising:
When it is detected that the mobile terminal is going to perform handover to one mobile access gateway among the plurality of other mobile access gateways, a handover start message is configured, and the configured handover start message is configured via the network interface. To the one mobile access gateway,
After receiving a handover confirmation message from the one mobile access gateway via the network interface, for the mobile terminal between the mobile access gateway and another mobile access gateway other than the one mobile access gateway It is checked whether a tunnel has been established. If a tunnel has already been established, the tunnel is deleted, and a tunnel for the mobile terminal is established between the mobile access gateway and the one mobile access gateway. A fast handover method characterized by establishing. A mobile access gateway fast handover method for communicating with a local mobility anchor and a plurality of mobile access gateways, comprising:
The local mobility anchor is for a mobile terminal between the one mobile access gateway and one other mobile access gateway in the plurality of mobile access gateways from one mobile access gateway in the plurality of mobile access gateways. For the mobile terminal between the other mobile access gateway and a plurality of mobile access gateways other than the one mobile access gateway. If an extra tunnel has already been established, and if an extra tunnel has already been established, a tunnel deletion message for deleting the extra tunnel is constructed and Fast handover method and transmits to the mobile access gateway.