JP4657286B2 - Method for handover of mobile communication terminal in mobile communication system with mixed asynchronous and synchronous networks - Google Patents

Description

  The present invention relates to a handover method in a mobile communication network, and more particularly, in a mobile communication system in which an asynchronous network and a synchronous network coexist, an interworking operation unit for exchanging signals between an asynchronous switch and a synchronous switch and the switch The present invention relates to a handover method of a mobile communication terminal using a message transmission protocol (ISUP).

  With the development of mobile communication technology, mobile communication networks have changed over generations. Currently, synchronous mobile communication systems (CDMA mobile communication systems) called 2-generation or 2.5-generation networks and asynchronous mobiles called 3-generation networks The communication system (WCDMA mobile communication system) coexists.

  Along with the development of mobile communication network technology, mobile communication terminals (Dual Band Dual Mode Terminals; DBDM mobile communication terminals) that can be used in both synchronous and asynchronous systems have been developed. By using the mobile communication terminal, it is possible to use services of different systems in the asynchronous system system area and the synchronous system system area. Such a DBDM mobile communication terminal includes an antenna, a synchronous modem unit that is a module for a synchronous mobile communication service, an asynchronous modem unit that is a module for an asynchronous mobile communication service, and a common module.

  However, the asynchronous mobile communication system is still in the initial stage of service, and enormous investment costs are required to implement the system. Therefore, the service cannot be provided in a wide area, and is implemented in a form overlapping the synchronous mobile communication system area. ing. Therefore, since the service area of the asynchronous mobile communication system is limited, when a subscriber of an asynchronous mobile communication system that uses the service in the asynchronous area moves to a synchronous area where the asynchronous mobile communication service is not provided, There was a problem that was cut off.

  As described above, when the asynchronous mobile communication system and the synchronous mobile communication system coexist, and especially when the asynchronous mobile communication system area is smaller than the synchronous mobile communication system area, continuous communication between the asynchronous mobile communication system and the synchronous mobile communication system is possible. Handover is required to provide a secure service. Such a handover is not only performed when the mobile communication terminal is in a call state, but also when the calling mobile communication terminal is waiting for a callee's response and the incoming mobile communication terminal is in an incoming alert (alerting) state. Need to be supported.

  An object of the present invention to solve the above-described problems is to provide an asynchronous switch-synchronization as a mobile communication terminal using a voice call service in the asynchronous mobile communication system area moves to the synchronous mobile communication system area. A message transmission protocol (ISUP) between an exchange operating unit for exchanging signals between exchanges and the exchange is used to provide a continuous service without a call disconnection phenomenon.

  Another object of the present invention is to provide synchronous movement of an outgoing mobile communication terminal that is attempting to make a call in the asynchronous mobile communication system area and is waiting for a response from the incoming mobile communication terminal, or an incoming mobile communication terminal that is in an alert state when a call is received. To enable a handover to be performed using a message transmission protocol (ISUP) between an exchange operation unit and an exchange for exchanging signals between an asynchronous exchange and a synchronous exchange as moving to a communication system area There is also.

  According to one aspect of the present invention, a mobile communication in which an asynchronous mobile communication system including a Node B, a radio network controller and an asynchronous switch, and a synchronous mobile communication system including a base station, a base station controller and a synchronous switch are mixed. In the system, the asynchronous exchange and the synchronous exchange are interconnected by an interoperating operation unit, and the asynchronous exchange and the synchronous exchange are respectively connected to a dual stack home location register, and the asynchronous mobile communication system and the synchronous mobile communication system (A) The radio network controller transmits a handover request message to the asynchronous exchange in response to a handover request from the mobile communication terminal; b) The asynchronous exchange is handed over to the interoperating operation unit. (C) The interoperating operation unit requests the dual stack home location register to transmit the subscriber information of the mobile communication terminal and receives it; (d) The interoperating operating unit Transmitting a handover instruction message to the synchronous switch, and the synchronous switch requesting handover to the base station controller / base station; (e) the base station / base station controller requesting the mobile communication terminal Allocating a direction traffic channel and transmitting a response message to the handover request to the synchronous switch; (f) the synchronous switch transmits a response message to the handover instruction to the interlink operation unit, and the interlink operation unit Transmits a response message for the handover request to the asynchronous exchange, and the same as the asynchronous exchange. A step of setting up a trunk line with the exchange; (g) the asynchronous exchange transmits an initial address message to the interoperating operation unit and receives a response to the initial address message, and the exchange between the asynchronous exchange and the synchronous exchange; (H) the asynchronous switch reports to the radio network controller that resource allocation for handover has been completed; (i) the radio network controller communicates with the node B; A step of instructing the mobile communication terminal to perform handover; (j) a step of switching the mobile communication terminal to a synchronous mobile communication system connection mode; and (k) the interworking operation unit transmits an access signal to the asynchronous exchange. (L) the mobile communication terminal transmits a frame and a preamble to the base station / base station controller via a reverse traffic channel, and And (m) releasing the connection between the asynchronous mobile communication system and the synchronous mobile communication system.

  According to another feature of the present invention, the mobile communication terminal may be in a voice call state, a waiting state for answering a call try, or an incoming alert state.

  When the mobile communication terminal is in a response waiting state due to a transmission try, preferably, the handover request message and the handover instruction message include information indicating that the mobile communication terminal is in a response waiting state, and more preferably (N) the asynchronous switch notifies the interoperating operation unit that the incoming mobile communication terminal is connected by the response of the incoming mobile communication terminal; (o) the interoperating operation unit provides an intersystem to the synchronous switch. Transmitting a response message, and the synchronous switch reporting to the base station controller / base station that the incoming mobile communication terminal has responded and connected; and (p) the synchronous switch is the interoperating operation unit. Transmitting a response signal to the intersystem response message.

  When the mobile communication terminal is in an incoming alert state, preferably, the handover request message and the handover instruction message include information indicating that the mobile communication terminal is in an incoming alert state, and more preferably (Q) the base station / base station controller notifying that the mobile communication terminal is connected to the synchronous switch when the mobile communication terminal in the incoming alert responds to the alert; (r) the synchronous switch; Transmitting an intersystem response message to the interworking operation unit, and the interworking operation unit reporting to the asynchronous exchange that the mobile communication terminal is connected in response to the alert; and (s) the mutual operation A step of transmitting a response signal for the inter-system response message to the synchronous switch; To include.

  According to still another aspect of the present invention, when the trunk is set between the asynchronous switch and the synchronous switch, the asynchronous switch sends an IAM (Initial Address Message), which is an ISUP message, to the interoperating operation unit. The interoperating operation unit transmits an ACM (Address Completion Message) which is an ISUP message to the asynchronous exchange.

  According to still another aspect of the present invention, the step of releasing the connection between the asynchronous mobile communication system and the synchronous mobile communication system is performed when the base station / base station controller has completed handover to the exchange. And the exchange notifies the interoperating operation unit that the handover has been completed; the interoperating operation unit requests the asynchronous exchange to release the connection, and uses the ISUP message to And a process of reporting that the mobile communication terminal is connected; and a process of releasing the connection between the asynchronous exchange and the Node B / radio network controller.

  According to still another aspect of the present invention, a handover request message transmitted from the radio network controller to the asynchronous switch includes a handover related message used in the synchronous mobile communication system, and an adjacent cell of the mobile communication terminal. Information and neighboring base station information, and parameters including handover type, cause of handover, source base station controller ID, target base station controller ID, RAB information and radio section related information.

  In this case, the asynchronous exchange refers to neighboring cell information and neighboring base station information of the mobile communication terminal and determines whether the handover is within the asynchronous mobile communication system or the handover to the synchronous mobile communication system. It is desirable to further include.

  According to still another aspect of the present invention, the asynchronous exchange transmits an asynchronous identification number (MSISDN) of the mobile communication terminal together when the asynchronous exchange transmits a handover request message to the interworking operation unit.

  According to still another aspect of the present invention, the subscriber information received by the interworking operation unit from the dual stack home location register includes a synchronous network identifier (MIN, ESN) of the mobile communication terminal.

  According to still another aspect of the present invention, the step of the interworking operation unit requesting subscriber information of the mobile communication terminal from the dual stack home location register includes either a synchronous message or an asynchronous message. Use.

  According to still another aspect of the present invention, the interworking operation unit includes a billing ID including ID information of a synchronous switch connected to the asynchronous switch before transmitting a handover instruction message to the synchronous switch. Is generated and transmitted in the handover instruction message, and is transmitted including the internal switching circuit ID (Inter MSC Circuit ID) for each handover section.

  According to still another aspect of the present invention, the handover request message transmitted to the synchronous exchange by the interoperating operation unit includes parameters including a billing ID, an ESN, an internal exchange circuit ID, and a MIN, and the synchronous exchange The response message transmitted to the interoperating operation unit includes parameters including CDMA channel data and a CDMA channel list.

  According to still another aspect of the present invention, when the asynchronous exchange transmits a resource allocation completion message to the radio network controller, the resource allocation completion message includes a message type, an RRC container, and a RAB list to be released. It also includes parameters.

  According to another aspect of the invention, the access signal includes an invoke ID, an application protocol data unit (APDU), and selected radio resource information.

  According to still another aspect of the present invention, a call release request is received from an incoming or outgoing mobile communication terminal after the outgoing mobile communication terminal completes a handover and the incoming mobile communication terminal responds. The exchange receiving the call release request transmits a trunk connection release and call release request message between the exchanges to the interoperating operation unit, and the interoperating operation unit responds to this to synchronize with the asynchronous exchange. The trunk line set up with the exchange is released.

  In this case, it is preferable that the call release request message includes a parameter including an internal MSC circuit ID, a release reason, a billing ID, and a MIN, and the response message includes a parameter including a billing ID.

  In the present invention, the asynchronous mobile communication system overlaps the synchronous mobile communication system, and the dual-band dual-mode mobile communication terminal is in the state of the synchronous mobile communication system from the asynchronous mobile communication system during a voice call, waiting for a response, or during an incoming alert. Overcoming the service difference between generations by allowing handover to be performed using ISUP, which is a message transmission protocol between the exchange operation unit for exchanging messages between exchanges and the exchange. And having the effect of providing a good quality service.

  In addition, according to the present invention, the asynchronous mobile communication system does not have to be implemented over an unnecessarily large area, so that it is possible to reduce the investment cost required for the design of the asynchronous mobile communication system.

  Hereinafter, a method for handover of a mobile communication terminal in a mobile communication system in which an asynchronous network and a synchronous network are mixed will be described in detail with reference to the accompanying drawings and preferred embodiments of the present invention.

  FIG. 1 is a configuration diagram of a mobile communication network to which the present invention is applied.

  A mobile communication terminal 10 applied to the present invention is a dual-band dual-mode (hereinafter referred to as 'DBDM') mobile communication terminal, which is capable of simultaneously providing an asynchronous mobile communication service and a synchronous mobile communication service, A synchronous modem unit that is a module for a synchronous mobile communication service, an asynchronous modem unit that is a module for an asynchronous mobile communication service, and a common module, and each of the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 Wireless and voice and data services can be used.

  Asynchronous mobile communication system 20 includes Node B as a base station for wireless section communication with mobile communication terminal 10 and a radio network controller (Node B / RNC) 210 for controlling Node B, and a radio network controller. (RNC) is connected between an asynchronous switch (MSC) 220 that performs call exchange for providing services to the mobile communication terminal 10, and a radio network controller (RNC) and a GPRS (General Packet Radio Service) network 240. The SGSN (Serving GPRS Support Node) 230 is connected to maintain the location track of the mobile communication terminal 10 and performs access control and security functions, and the SGSN 230 is connected to the IP network 70 via the GPRS (General Packet Radio Service) network 240. GGSN (Gateway GPRS Support Node) 250 that is connected and supports the linkage with external packets.

  The synchronous mobile communication system 30 also includes a base station that supports wireless communication with the mobile communication terminal 10 and a base station controller (BTS / BSC) 310 for controlling the base station, and one or more base station controls. A switch (MSC) 320 connected to the mobile station to exchange calls, a packet data service node (PDSN) 330 connected to a base station controller (BSC) and providing packet data services to subscribers, and packet data A data core network (DCN) 340 for supporting connection between the service node 330 and the IP network 70 is configured.

  Further, the exchanges 220 and 320 of the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 are interconnected by an interworking operation unit (IIF) 60. The transmitted asynchronous message is converted into a synchronous message and transmitted to the synchronous switch 320, and the synchronous mobile communication system information is constructed and managed as a database.

  Asynchronous switch 220 and synchronous switch 320 are also No. 7 is connected to a common signal network 40 and is connected to a dual stack home location register (D-HLR) 50 via this, and the dual stack home location register 50 joins the DBDM mobile communication terminal 10 to the asynchronous mobile communication system 10. The information and the synchronous mobile communication system subscription information corresponding thereto are stored and managed so that the asynchronous exchange 220 and the synchronous exchange 320 can refer to them when performing services such as handover.

(First embodiment)
The first embodiment of the present invention discloses a method for handing over a mobile communication terminal during a voice call in a mobile communication system in which an asynchronous network and a synchronous network are mixed.

  In the network configuration described above, the mobile communication terminal 10 that is located in the area of the asynchronous mobile communication system 20 and uses voice communication has the signal strength with the currently connected Node B and the signal strength transmitted and received with the adjacent base station. Is periodically measured and reported to the node B. When the signal strength with the node B falls below a specified threshold value, the node B reports that a handover event has occurred to the asynchronous exchange 220 via the RNC. . At this time, the Node B / RNC 210 transmits the neighbor cell information detected by the mobile communication terminal 10 and the base station ID to the asynchronous exchange 220 together.

  When the asynchronous exchange 220 receives the handover request message from the RNC, the asynchronous mobile communication system 20 determines whether the handover is between adjacent cells in the asynchronous mobile communication system 20 by referring to the adjacent cell information, base station ID, etc. received from the RNC. It is determined whether it is a handover to 30.

  In the case of a handover between adjacent cells in the asynchronous mobile communication system 20, the asynchronous exchange 220 performs a handover to an adjacent cell, whereas in the case of a handover to the synchronous mobile communication system 30, A handover is performed to the synchronous exchange 320 via the IIF 60. For this purpose, the IIF 60 must convert an asynchronous message into a synchronous message and transmit it to the synchronous exchange 320, and construct and manage the synchronous mobile communication system information in advance as a database. This database includes exchange information, signal points, trunk information related to a dedicated channel (Dedicate Channel), and the like. The IIF 60 selects the handover target switch 320 based on the handover request from the asynchronous switch 220 and the synchronous mobile communication system information, generates a billing ID including the handover target switch ID, and uses it in the subsequent handover process.

  The handover procedure will be described in detail with reference to FIGS. 2 and 3 as follows.

  FIG. 2 is a diagram for explaining a handover concept that occurs when a mobile communication terminal that uses a voice call service in the asynchronous mobile communication system area moves to the synchronous mobile communication system area. 5 is a flowchart for explaining a method for handing over a mobile communication terminal during a voice call associated with FIG.

  As the mobile communication terminal 10 that used voice communication in the asynchronous mobile communication system 20 area moves to the synchronous mobile communication system 30 area, the mobile communication terminal 10 senses a signal from the synchronous mobile communication system 30. The signal strength from the node B of the asynchronous mobile communication system 20 and the signal strength with the adjacent base station (or node B) are periodically measured and reported to the node B. As a result, when it is confirmed that the signal strength between the mobile communication terminal and the node B is equal to or less than the specified value at the node B currently connected to the mobile communication terminal 10, a handover is requested to the asynchronous exchange 220 via the RNC. (IU Reloc Required) (S101).

  This handover request message (IU Reloc Required) includes a handover related message used in the synchronous mobile communication system. Also, the RNC transmits both adjacent base station information (base station ID) and adjacent cell information received from the mobile communication terminal 10, and the asynchronous switch 220 uses this information to perform handover between adjacent cells in the asynchronous mobile communication system. Or whether it is a handover to the synchronous mobile communication system 30. As shown in FIG. 4, the handover request message (IU Reloc Required) transmitted from the RNC to the asynchronous exchange 220 includes a message type, a handover type, a cause of the handover, a source base station controller ID, and a target base station controller. Parameters such as ID, RAB (Radio Access Bearer) information, and radio section related information are included. In addition, the RNC additionally transmits handover related information used in the synchronous mobile communication system in the Old BSS To New BSS Information parameter included in the handover request message, and a specific list is shown in FIG. Street.

  The asynchronous exchange 220 that has received the handover request message transmits an asynchronous message for requesting handover to the interoperating operation unit 60 (MAP Prep Handover Req) (S102). At this time, an extension container is added to the asynchronous message and the asynchronous identification number (MSISDN) of the mobile communication terminal 10 is transmitted together. This message includes an invoke ID, a target cell ID, a target wireless network as shown in FIG. Includes parameters such as controller ID, MSISDN, etc.

  Thereafter, the interworking operation unit 60 refers to the asynchronous subscriber information (MSISDN) received from the asynchronous exchange 220 and requests the dual stack home location register 50 to transmit the subscriber information (Call Data Request) (S103). . That is, it requests the synchronous network identifier (MIN, ESN) of the mobile communication terminal 10. In step S103, the interworking operation unit 60 may request the subscriber's synchronous network identifier information from the dual stack home location register 50 using an asynchronous message (MAP_SEND_IMSI).

  Upon receiving the subscriber information request from the interlinkage operation unit 60, the dual stack home location register 50 refers to the database and extracts the synchronous network identifier information (MIN, ESN) of the corresponding subscriber. (Call Data Req Ack) (S104). Here, the synchronous network message (Call Data Request) for requesting the synchronous network identifier information of the subscriber includes parameters such as a billing ID and digits (ie, MSISDN) as shown in FIG. (Call Data Req Ack) includes parameters such as ESN, MIN, MSCID, and the like. When an asynchronous message (MAP_SEND_IMSI) is used when requesting the subscriber's synchronous network identifier information, the types of parameters included in this message are as shown in FIG.

  The interoperating operation unit 60 that has received the subscriber information from the dual stack home location register 50 instructs the synchronous switch 320 to perform handover (Facilities Directive 2) (S105), and the synchronous switch 320 sends to the base station controller / base station 310. A handover is requested (Handover Request) (S106).

  As described above, the interworking operation unit 60 generates a billing ID and includes it in the handover instruction message (Facilities Directive 2) before transmitting the handover instruction message (Facilities Directive 2) to the synchronous exchange 320. An exchange circuit ID (Inter MSC Circuit ID) is included and transmitted. Here, the billing ID includes ID information of the synchronous switch 320 connected to the asynchronous switch 220.

  The base station / base station controller 310 that receives the handover request from the exchange 320 transmits null frames (null forward traffic channel frames) to the synchronous modem unit of the mobile communication terminal via the forward traffic channel. Then, the forward channel is allocated (S107), and then the base station / base station controller 310 transmits a response message (Handover Request Ack) to the handover request to the exchange 320 (S108). Further, the exchange 320 transmits a response message (Facilities Directive 2 Ack) to the handover instruction to the interlinkage operation unit 60 (S109), and the interlinkage operation unit 60 sends a response message (MAP to the handover request in step S102 to the asynchronous exchange 220. Prep Handover Resp) is transmitted (S110). Accordingly, a trunk line between the asynchronous exchange 220 and the synchronous exchange 320 is set.

  More specifically, the interworking operation unit 60 sets a mapping relationship between a dedicated channel that is a logical trunk line setting identifier and a physical trunk line, and uses this information as a handover request message (Facilities Directive 2). ) Is set to the internal exchange circuit ID (Inter MSC Circuit ID) and transmitted to the synchronous exchange 320, and when a response message (Facilities Directive 2 Ack) is transmitted from the synchronous exchange 320, the asynchronous exchange 220 and the synchronous exchange 320 A trunk line is set. As shown in FIG. 9, the handover request message (Facilities Directive 2) transmitted and received between the interoperating operation unit 60 and the synchronous exchange 320 has parameters such as billing ID, ESN, internal exchange circuit ID, MIN, and the like. The response message (Facilities Directive 2 Ack) includes parameters such as CDMA channel data and a CDMA channel list.

  Subsequently, the asynchronous exchange 220 transmits an IAM (Initial Address Message), which is an initial address message, to the interlink operation unit 60, and the interlink operation unit 60 transmits an ACM (Address Completion Message) as a response thereto. A trunk is set up between the exchange 220 and the synchronous exchange 320, whereby a call is routed (S111, S112). Messages between exchanges for trunk setting are transmitted and received by ISUP.

  As described above, after the trunk line and the trunk between the exchanges are set, the asynchronous exchange 220 reports to the Node B / RNC 210 that the resource allocation for the handover is completed (IU Relocation Command) (S113). The Node B / RNC 210 that has received the request requests the asynchronous modem unit of the mobile communication terminal 10 to perform handover (Handover from UTRAN Command) (S114). Here, the message (IU Relocation Command) reporting that resource allocation is completed includes parameters such as a message type, an RRC container, and a RAB list to be released, as shown in FIG. Further, a handover message (HDM) is transmitted using the L3Information parameter of the resource allocation completion report message, and a specific parameter list is as shown in FIG.

  Thereafter, the asynchronous modem unit of the mobile communication terminal transmits channel assignment information to the synchronous modem unit (Channel Assignment) (S115), and the interlink operation unit 60 requests an access signal from the asynchronous switch 220 (MAP Process Access Signaling Req). ) (S116), the access signal includes an invoke ID, application protocol data unit (APDU), selected radio resource information, etc., and a specific parameter list is as shown in FIG.

  Also, the synchronous modem unit of the mobile communication terminal transmits a frame or preamble to the base station / base station controller 310 of the synchronous mobile communication system via the reverse traffic channel (Reverse Traffic Channel Frames or Traffic Channel Preamble) (S117). ) And reports that the handover has been completed (Handover Completion Message) (S118), and the base station / base station controller 310 that has received the message transmits a response signal (BS Ack Order) (S119). Then, the synchronous modem unit notifies the asynchronous modem unit that the connection with the synchronous mobile communication system has been completed (Call Connection) (S120).

  Subsequently, the base station / base station controller 310 reports to the exchange 320 that the handover has been completed (Handover Complete) (S121), and the exchange 320 notifies the interworking operation unit 60 that the handover has been completed. (Mobile On Channel) (S122), the interoperating operation unit 60 that has received the request requests the asynchronous exchange 220 to release the connection (MAP Send End Signal Req) (S123).

  Further, the interoperating operation unit 60 transmits a message notifying that the synchronous switch 320 and the mobile communication terminal are connected to the asynchronous switch 220 (ANSWER) (S124), and the connection between the asynchronous switch 220 and the Node B / RNC. Is released (IU Release Command, IU Release Complete) (S125, S126).

  Here, the handover completion message (Mobile On Channel) transmitted by the exchange 320 to the interlinkage operation unit 60 is created including parameters as shown in FIG. 13, and the connection that the interlinkage operation unit 60 transmits to the asynchronous exchange 220. The cancellation request message (MAP Send End Signal Req) includes parameters as shown in FIG. Further, messages (IU Release Command and IU Release Complete) transmitted and received for releasing the connection between the asynchronous exchange 220 and the Node B / RNC are created as shown in FIGS. 15 and 16, respectively.

  The call release process after the handover to the synchronous mobile communication system for the mobile communication terminal in a voice call in the asynchronous mobile communication system is completed according to the procedure described above is as follows. The call release may be requested first from the subscriber's mobile communication terminal in the asynchronous mobile communication system area or may be requested first from the subscriber's mobile communication terminal handed over to the synchronous mobile communication system area. In the present embodiment, a case will be described in which a subscriber's mobile communication terminal in the asynchronous mobile communication system area requests call release.

  As the mobile communication terminal releases the call, the call between the asynchronous exchange 220 and the synchronous exchange 320 is released (Call Release) (S127), and the trunk connection between the exchanges is released (Release) (S128). . Thereafter, the asynchronous exchange 220 reports the completion of the connection release to the interlink operation unit 60 (MAP Send End Signal Resp) (S129), and the interlink operation unit 60 sends a call release request message (Facilities Release) is transmitted (S130), and the synchronous exchange 320 that has received this message responds to this (Facilities Ack), thereby canceling the trunk line setting set between the exchanges (S131). Here, the call release request message (Facilities Release) includes parameters such as the internal MSC circuit ID, release reason, billing ID, and MIN, as shown in FIG. 17, and the response message (Facilities Ack) is the billing ID. Including parameters such as

  In this embodiment, the asynchronous exchange determines whether it is a handover within the asynchronous mobile communication system or a handover to the synchronous mobile communication system in response to an RNC handover request. When it is confirmed that the handover to the synchronous mobile communication system is performed, the interoperable operation unit (IIF) is used as a converter, and the message is transmitted / received to / from the exchange of the synchronous mobile communication system using ISUP which is a message transmission protocol between the exchanges. Therefore, the interoperating operation unit must construct and store the synchronous mobile communication system information as a database in advance so that the handover can be performed.

(Second embodiment)
The second embodiment of the present invention discloses a handover method for waiting for a response of an originating mobile communication terminal in a mobile communication system in which an asynchronous network and a synchronous network are mixed.

  In the network configuration described above, a method for handing over while the mobile communication terminal 10 located in the region of the asynchronous mobile communication system 20 tries to make a call and waits for a response from the incoming mobile communication terminal will be schematically described with reference to FIG. It is as follows.

  FIG. 18 is a diagram for explaining a handover concept during response waiting of an originating mobile communication terminal between an asynchronous network and a synchronous network according to the second embodiment of the present invention. The communication terminals will be described separately for the outgoing mobile communication terminal 10a and the incoming mobile communication terminal 10b.

  In the asynchronous mobile communication system 20 area A, when the incoming mobile communication terminal 10b is in the incoming alert state via the Node B / RNC 210 due to the outgoing try of the outgoing mobile communication terminal 10a, the outgoing mobile communication terminal 10a When moving to the boundary region C with the region B, the originating mobile communication terminal 10a requests a handover to the node B of the asynchronous mobile communication system 20, and the node B requests a handover to the asynchronous switch 220 via the RNC.

  As a result, a handover procedure between the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 for the originating mobile communication terminal 10a is started, the handover is completed, and the asynchronous switch 220 and the synchronous switch 320 are connected to the interoperating operation unit 60. The outgoing mobile communication terminal 10a is connected via the BTS / BSC 310 of the synchronous mobile communication system 30 and waits for a response from the incoming mobile communication terminal 10b.

  For such a handover of the outgoing mobile communication terminal waiting for a response, the mobile communication terminal 10a periodically measures the signal strength between the node B and the adjacent base station and reports it to the node B. When the signal strength falls below a specified threshold, the Node B reports to the asynchronous switch 220 that a handover event has occurred via the RNC. At this time, the Node B / RNC 210 transmits the neighboring cell information detected by the mobile communication terminal 10a, the base station ID, and the like to the asynchronous exchange 220 together.

  When receiving the handover request message from the RNC, the asynchronous exchange 220 refers to the neighboring cell information, base station ID, etc. received from the RNC, and determines whether the handover is between neighboring cells in the asynchronous mobile communication system 20 or the synchronous mobile communication. It is determined whether it is a handover to the system 30.

  In the case of a handover between adjacent cells in the asynchronous mobile communication system 20, the asynchronous exchange 220 performs a handover to an adjacent cell, whereas in the case of a handover to the synchronous mobile communication system 30, A handover is made to the synchronous exchange 320 via the IIF 60. For this purpose, the IIF 60 must convert an asynchronous message into a synchronous message and transmit it to the synchronous exchange 320, and construct and manage the synchronous mobile communication system information in advance as a database. This database includes exchange information, signal points, trunk information related to a dedicated channel (Dedicate Channel), and the like. The IIF 60 selects the handover target switch 320 based on the handover request from the asynchronous switch 220 and the synchronous mobile communication system information, generates a billing ID including the handover target switch ID, and uses it in the subsequent handover process. Further, the IIF 60 sets up a trunk between the asynchronous exchange 220 and the synchronous exchange 320 so that messages can be exchanged via ISUP, which is a message transmission protocol between the exchanges.

  The handover procedure during the response waiting of the originating mobile communication terminal will be described in more detail with reference to FIGS. 19 and 20 as follows.

  19 and 20 are flowcharts for explaining a handover method from an asynchronous network to a synchronous network of a mobile communication terminal waiting for an outgoing response according to the second embodiment of the present invention. The modem unit and the synchronous modem unit mean components of the outgoing mobile communication terminal.

  Similarly, in the asynchronous mobile communication system 20 area, the mobile communication terminal 10a that has attempted to make a call to the mobile communication terminal 10b located in the asynchronous mobile communication system area 20 gradually moves to the synchronous mobile communication system 30 area. By positioning the synchronous network area in the overlapping area, the mobile communication terminal 10a senses the signal from the synchronous mobile communication system 30, and the signal strength from the node B of the asynchronous mobile communication system 20 and the adjacent base station ( Alternatively, the signal strength with the node B) is periodically measured and reported to the node B. As a result, when the node B currently connected to the mobile communication terminal 10a confirms that the signal strength between the mobile communication terminal 10a and the node B is equal to or less than the specified value, the asynchronous switch 220 is requested to perform a handover via the RNC. (IU Reloc Required) (S201).

  A series of processes (refer to S201 to S226 in FIGS. 19 and 20) after the handover is requested and the handover is completed and the connection is canceled by the connection cancellation request are the processes of the first embodiment described above ( Since this is substantially the same as S101 to S126 in FIG. 3, detailed description thereof will be omitted.

  However, in the case of the second embodiment, when the asynchronous exchange 220 that has received the handover request message transmits an asynchronous message requesting handover to the interoperating operation unit 60 (MAP Prep Handover Req) (S202), the asynchronous message An extension container is added to the mobile terminal 10a to transmit both the asynchronous identification number (MSISDN) of the mobile communication terminal 10a and that the mobile communication terminal 10a is in a response waiting state. For this purpose, a handover request message (MAP Prep The state of the mobile communication terminal 10a must be indicated using parameters included in (Handover Req). This message (MAP Prep Handover Req) includes parameters such as invoke ID, target cell ID, target radio network controller ID, MSISDN, etc., as shown in FIG.

  Then, the handover request message (Facilities Directive 2) transmitted / received between the interoperating operation unit 60 and the synchronous exchange 320 is, as shown in FIG. 9, billing ID, ESN, internal exchange circuit ID, MIN, handover state. In particular, the handover state parameter is set as an identifier indicating that it is in a response standby state, and its response message (Facilities Directive 2 Ack) includes CDMA channel data, CDMA channel list, etc. Parameters such as

  When the handover to the synchronous mobile communication system for the outgoing mobile communication terminal 10a waiting for a response is completed by the procedure described above, the incoming terminal in the asynchronous mobile communication system area-asynchronous switch-interoperating operation unit-synchronous switch- A call is set up between the calling terminals.

  Thereafter, when the incoming mobile communication terminal 10b responds, the node B / RNC to which the incoming mobile communication terminal 10b is connected reports this to the asynchronous exchange 220 (BICC or ISUP ANSWER) (S227), and the asynchronous exchange operates the interoperating operation unit. A forward access signal is transmitted to 60 (MAP Forward Access Signaling Req) (S228).

  As a result, the interworking operation unit 60 recognizes that the receiving terminal has responded and transmits an intersystem answer message (Intersystem Answer) to the synchronous switch 320 (S229). Subsequently, the synchronous switch 320 transmits the base station controller. / While reporting that the receiving terminal has responded to the base station 310 (Progress) (S230), a response message (Intersystem Answer Ack) to the inter-system response message is transmitted to the interoperating operation unit 60 (S231).

  The intersystem answer message (Intersystem Answer) includes parameters such as an internal MSC circuit ID, MIN, ESN, etc., as shown in FIG.

  Through the procedure described above, the handover to the synchronous mobile communication system for the mobile communication terminal waiting for a response in the asynchronous mobile communication system is completed, and the incoming mobile communication terminal responds between the caller and the callee. After the call is started, the call is released. Since the call release process is the same as that in the first embodiment, a detailed description thereof will be omitted.

  In this embodiment, as the mobile communication terminal located in the asynchronous area moves to the synchronous network area in the response waiting state, the RNC requests a handover to the asynchronous exchange, and the asynchronous exchange is in the asynchronous mobile communication system. Whether it is a handover to a synchronous mobile communication system. When it is confirmed that the handover is to the synchronous mobile communication system, the interoperable operation unit (IIF) is used as a converter, and the exchange of the synchronous mobile communication system is exchanged by using ISUP which is a message transmission protocol between the exchanges. A handover can be performed while transmitting and receiving a message, and at this time, the mobile communication terminal to be handed over is notified that it is in a response standby state.

  When the handover to the synchronous mobile communication system is completed and the incoming mobile communication terminal responds, the asynchronous exchange notifies the interoperating operation section that the incoming mobile communication terminal has responded, so that the interoperating operation section The inter-system response message is transmitted to notify that the incoming mobile communication terminal has responded to the alert so that the handover can be performed completely.

(Third embodiment)
The third embodiment of the present invention discloses a handover method during an incoming call alert of an originating mobile communication terminal in a mobile communication system in which an asynchronous network and a synchronous network are mixed.

  In the network configuration described above, a method in which the mobile communication terminal 10 located in the area of the asynchronous mobile communication system 20 performs a handover during an incoming alert (alerting) will be schematically described with reference to FIG. .

  FIG. 22 is a diagram for explaining a handover concept in an incoming alert between an asynchronous network and a synchronous network according to the present invention. For convenience of explanation, a mobile communication terminal is connected to an outgoing mobile communication terminal 10a and an incoming call. The description will be divided into the mobile communication terminal 10b.

  In the asynchronous mobile communication system 20 area A, when the incoming mobile communication terminal 10b is in the incoming alert state via the Node B / RNC 210 due to the outgoing try of the outgoing mobile communication terminal 10a, the incoming mobile communication terminal 10b When moving to the boundary region C with the region B, the incoming mobile communication terminal 10b requests a handover to the node B of the asynchronous mobile communication system 20, and the node B requests a handover to the asynchronous exchange 220 via the RNC.

  Accordingly, a handover procedure between the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 for the incoming mobile communication terminal 10b is started, and the handover is completed and the asynchronous switch 220 and the synchronous switch 320 are connected to each other. When the connection is established via the communication terminal 60, the outgoing alert by the outgoing mobile communication terminal 10 a is transmitted to the incoming mobile communication terminal 10 b via the BTS / BSC 310 of the synchronous mobile communication system 30.

  For such handover during an incoming alert, the mobile communication terminal 10 periodically measures the signal strength between the node B and the adjacent base station and reports it to the node B, and the signal strength with the node B is designated. Node B reports to the asynchronous switch 220 that a handover event has occurred via the RNC. At this time, the Node B / RNC 210 transmits the neighboring cell information detected by the mobile communication terminal 10 and the base station ID to the asynchronous exchange 220 together.

  When receiving the handover request message from the RNC, the asynchronous exchange 220 refers to the neighboring cell information received from the RNC, the base station ID, etc. It is determined whether it is a handover to the system 30.

  In the case of a handover between adjacent cells in the asynchronous mobile communication system 20, the asynchronous exchange 220 performs a handover to an adjacent cell, whereas in the case of a handover to the synchronous mobile communication system 30, A handover is performed to the synchronous exchange 320 via the IIF 60. For this purpose, the IIF 60 must convert the asynchronous message into a synchronous message and transmit it to the synchronous switch 320, and construct and manage the synchronous mobile communication system information in advance as a database. This database includes switch information, signal points, trunk information related to the dedicated channel (Dedicate Channel), and the like. The IIF 60 selects the handover target switch 320 based on the handover request from the asynchronous switch 220 and the synchronous mobile communication system information, generates a billing ID including the handover target switch ID, etc., and uses it in the subsequent handover process. Further, the IIF 60 sets up a trunk between the asynchronous exchange 220 and the synchronous exchange 320 so that messages for handover can be exchanged via ISUP, which is a message transmission protocol between the exchanges.

  A handover procedure during such an incoming alert will be described in more detail with reference to FIGS. 23 and 24.

  FIGS. 23 and 24 are flowcharts for explaining a method for handing over a mobile communication terminal during an incoming alert according to a third embodiment of the present invention from an asynchronous network to a synchronous network. Section and synchronous modem section refer to components of the incoming mobile communication terminal.

  The mobile communication terminal 10b that was in the incoming alert in the asynchronous mobile communication system 20 area gradually moves to the synchronous mobile communication system 30 area, and is located in the area where the asynchronous network area and the synchronous network area overlap, thereby the mobile communication terminal 10b. Detects a signal from the synchronous mobile communication system 30, and periodically measures the signal strength from the node B of the asynchronous mobile communication system 20 and the signal strength with the adjacent base station (or the node B). To report to. As a result, when it is confirmed that the signal strength between the mobile communication terminal 10b and the node B is lower than the specified value at the node B that is currently connected to the mobile communication terminal 10b, the handover to the asynchronous exchange 220 is performed via the RNC. Request (IU Reloc Required) (S301).

  A series of processes (see S301 to S326 in FIGS. 23 and 24) after the handover is requested and the handover is completed and the connection is canceled by the connection cancellation request are the processes of the first embodiment described above. Since this is substantially the same as (see S101 to S126 in FIG. 3), detailed description thereof will be omitted.

  However, in the case of the third embodiment, the asynchronous switch 220 that has received the handover request message transmits the asynchronous message requesting handover to the interoperating operation unit 60 (MAP Prep Handover Req) (S302). The extension container must be added to the message to transmit both the asynchronous identification number (MSISDN) of the mobile communication terminal 10b and the mobile communication terminal 10b being in the incoming alert state. For this reason, the handover request message ( The state of the mobile communication terminal 10b must be indicated using parameters included in (MAP Prep Handover Req). This message (MAP Prep Handover Req) includes parameters such as invoke ID, target cell ID, target radio network controller ID, MSISDN, etc., as shown in FIG.

  Then, the handover request message (Facilities Directive 2) transmitted / received between the interoperating operation unit 60 and the synchronous exchange 320 is, as shown in FIG. 9, billing ID, ESN, internal exchange circuit ID, MIN, handover state. In particular, the handover state parameter is set as an identifier indicating the incoming alert state, and the response message (Facilities Directive 2 Ack) includes CDMA channel data, CDMA channel list, etc. Parameters such as

  When the handover to the synchronous mobile communication system for the mobile communication terminal in the incoming alert is completed by the procedure described above, the transmission terminal of the asynchronous mobile communication system area-asynchronous switch-interoperating operation unit-synchronous switch-receiving terminal Call setup is made in the meantime.

  Thereafter, when the incoming mobile communication terminal that has completed the handover responds, the base station / base station controller 310 reports this to the exchange 320 (Connect) (S327), and the exchange 320 sends an intersystem response to the interworking operation unit 60. A message (Intersystem Answer) is transmitted to notify that the incoming mobile communication terminal has responded (S328). Subsequently, the interworking operation unit 60 transmits an access signal to the asynchronous exchange 220 (MAP Process Access Signaling Req) (S329) to notify that the incoming mobile communication terminal has responded, while at the same time sending an intersystem response to the synchronous exchange 320. A response message (Intersystem Answer Ack) to the message is transmitted (S330).

  The intersystem answer message (Intersystem Answer) includes parameters such as an internal MSC circuit ID, MIN, ESN, etc., as shown in FIG.

  Through the procedure described above, the handover to the synchronous mobile communication system for the mobile communication terminal that is receiving the incoming alert in the asynchronous mobile communication system is completed, and the call between the caller and the callee is answered by the incoming mobile communication terminal. However, since the call release process is the same as in the first embodiment described above, a detailed description thereof will be omitted.

  In this embodiment, as the mobile communication terminal located in the asynchronous area moves to the synchronous network area in the incoming alert state, the RNC requests a handover to the asynchronous exchange. Whether it is a handover to a synchronous mobile communication system. When it is confirmed that the handover is to the synchronous mobile communication system, the interoperable operation unit (IIF) is used as a converter, and the exchange of the synchronous mobile communication system is exchanged by using ISUP which is a message transmission protocol between the exchanges. Handover can be performed while transmitting / receiving a message, and at this time, the mobile communication terminal to be handed over is notified that it is in an incoming alert state.

  When handover to the synchronous mobile communication system is completed and the mobile communication terminal in the incoming alert state responds, the synchronous exchange transmits an intersystem response message to the interworking operation unit, notifying that the mobile communication terminal has responded to the alert. Thus, the handover can be completely performed.

  The present invention described above can be understood by those skilled in the art to which the present invention pertains that the present invention can be implemented in other specific forms without changing the technical idea and essential features thereof. Will. Accordingly, it should be understood that the embodiments described above are illustrative in all aspects and not limiting. The scope of the present invention is defined by the following claims rather than the above detailed description, and all modifications or variations made from the meaning, scope, and equivalents of the claims are included in the scope of the present invention. Must be interpreted.

FIG. 1 is a configuration diagram of a mobile communication network to which the present invention is applied. FIG. 2 is a diagram for explaining a concept of handover during a voice call of a mobile communication terminal between an asynchronous network and a synchronous network according to the first embodiment of the present invention. FIG. 3 is a flowchart for explaining a handover method during a voice call of a mobile communication terminal between an asynchronous network and a synchronous network according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 5 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 6 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 7 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 8 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 9 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 10 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 11 is a diagram showing parameters included in a message used in the handover method according to the present invention. FIG. 12 is a diagram showing parameters included in a message used in the handover method according to the present invention. FIG. 13 is a diagram showing parameters included in a message used in the handover method according to the present invention. FIG. 14 is a diagram showing parameters included in a message used in the handover method according to the present invention. FIG. 15 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 16 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 17 is a diagram illustrating parameters included in a message used in the handover method according to the present invention. FIG. 18 is a diagram for explaining a handover concept during a response waiting of an originating mobile communication terminal between an asynchronous network and a synchronous network according to the second embodiment of the present invention. FIG. 19 is a flowchart for explaining a handover method during a response waiting of an originating mobile communication terminal between an asynchronous network and a synchronous network according to a second embodiment of the present invention. FIG. 20 is a flowchart for explaining a handover method during standby for a response of an originating mobile communication terminal between an asynchronous network and a synchronous network according to the second embodiment of the present invention. FIG. 21 is a diagram showing parameters included in a message used in the handover method according to the present invention. FIG. 22 is a diagram for explaining a handover concept during an incoming alert between the asynchronous network and the synchronous network according to the third embodiment of the present invention. FIG. 23 is a flowchart for explaining a handover method during an incoming alert between the asynchronous network and the synchronous network according to the third embodiment of the present invention. FIG. 24 is a flowchart for explaining a handover method during an incoming alert between the asynchronous network and the synchronous network according to the third embodiment of the present invention.

Claims (19)

In a mobile communication system in which an asynchronous mobile communication system including a Node B, a radio network controller and an asynchronous switch and a synchronous mobile communication system including a base station, a base station controller and a synchronous switch are mixed, the asynchronous switch and the synchronous switch are A dual-band dual-mode mobile communication terminal that is interconnected by an interoperating operation unit, the asynchronous switch and the synchronous switch being connected to a dual stack home location register, and capable of communicating with the asynchronous mobile communication system and the synchronous mobile communication system. A handover method of
(A) The wireless network controller transmits a handover request message to the asynchronous exchange in response to a handover request of the mobile communication terminal;
(B) the asynchronous exchange transmits a handover request message to the interoperating operation unit;
(C) The interworking operation unit requests and receives transmission of subscriber information of the mobile communication terminal from a dual stack home location register;
(D) The interoperating operation unit transmits a handover instruction message to the synchronous switch, and the synchronous switch requests a handover to the base station controller / base station;
(E) The base station / base station controller allocates a forward traffic channel to the mobile communication terminal and transmits a response message for a handover request to the synchronous switch;
(F) The synchronous exchange transmits a response message to the handover instruction to the interlinkage operation unit, and the interlinkage operation unit transmits a response message to the handover request to the asynchronous exchange, and the asynchronous exchange and the synchronous exchange A trunk line is established between
(G) The asynchronous switch transmits an initial address message to the interoperating operation unit, receives a response to the initial address message, and establishes a trunk between the asynchronous switch and the synchronous switch;
(H) the asynchronous switch reports to the radio network controller that resource allocation for handover has been completed;
(I) The radio network controller instructs the mobile communication terminal to perform handover via the Node B;
(J) The mobile communication terminal switches to a synchronous mobile communication system connection mode;
(K) The interoperating operation unit transmits an access signal to the asynchronous exchange;
(L) the mobile communication terminal transmits a frame and a preamble to the base station / base station controller via a reverse traffic channel and reports that the handover is completed; and (m) the asynchronous mobile communication Releasing a connection between the system and the synchronous mobile communication system.   The handover method according to claim 1, wherein the mobile communication terminal is in a voice call state.   The mobile communication terminal is in a response standby state due to a transmission try, and the handover request message and the handover instruction message include information indicating that the mobile communication terminal is in a response standby state. Item 2. The handover method according to Item 1. (N) a step of notifying that the incoming mobile communication terminal is connected to the interoperating operation unit by the asynchronous exchange according to a response of the incoming mobile communication terminal;
(O) The interoperating operation unit transmits an inter-system response message to the synchronous switch, and the synchronous switch reports that the incoming mobile communication terminal has connected in response to the base station controller / base station. The handover method according to claim 3, further comprising the step of: (p) the synchronous exchange transmitting a response signal to the inter-system response message to the interoperating operation unit.   The mobile communication terminal is in an incoming alert state, and the handover request message and the handover instruction message include information indicating that the mobile communication terminal is in an incoming alert state. Handover method. (Q) the base station / base station controller notifying that the mobile communication terminal is connected to the synchronous exchange when the mobile communication terminal in the incoming alert responds to the alert;
(R) the synchronous exchange transmits an intersystem response message to the interlinkage operation unit, and the interoperation operation unit reports to the asynchronous exchange that the mobile communication terminal is connected in response to the alert; and 6. The handover method according to claim 5, further comprising the step of: (s) the interoperating operation unit transmitting a response signal for the intersystem response message to the synchronous exchange.   When the trunk is set up between the asynchronous switch and the synchronous switch, the asynchronous switch transmits an IAM (Initial Address Message), which is an ISUP message, to the interoperating operation unit. 7. The handover method according to claim 1, wherein the handover method is performed by transmitting an ACM (Address Completion Message) which is an ISUP message to the exchange. The step of releasing the connection between the asynchronous mobile communication system and the synchronous mobile communication system includes:
A process in which the base station / base station controller reports to the exchange that the handover has been completed, and the exchange notifies the interoperating operation unit that the handover has been completed;
A process in which the interoperating operation unit requests the asynchronous switch to release the connection and reports that the synchronous switch and the mobile communication terminal are connected using an ISUP message; and the asynchronous switch and the Node B / wireless network The handover method according to any one of claims 1 to 6, further comprising a step of releasing the connection with the controller.   The handover request message transmitted by the radio network controller to the asynchronous exchange includes a handover related message used in the synchronous mobile communication system, adjacent cell information and adjacent base station information of the mobile communication terminal, and a handover type. And a cause of handover, a source base station controller ID, a target base station controller ID, RAB information, and parameters including radio section related information. The handover method as described.   The asynchronous exchange further includes a step of determining whether the handover is within the asynchronous mobile communication system or the handover to the synchronous mobile communication system by referring to the neighboring cell information and neighboring base station information of the mobile communication terminal. The handover method according to claim 9.   7. The asynchronous exchange number (MSISDN) of the mobile communication terminal is transmitted together with the asynchronous exchange when the handover request message is transmitted to the interoperating operation unit. The handover method described in 1.   7. The subscriber information received by the interworking operation unit from the dual stack home location register includes a synchronous network identifier (MIN, ESN) of the mobile communication terminal. The handover method described in one.   7. The step of requesting subscriber information of the mobile communication terminal from the interworking operation unit to the dual stack home location register uses one of a synchronous message and an asynchronous message. The handover method according to any one of the above.   The interworking operation unit generates a billing ID including ID information of a synchronous exchange connected to the asynchronous exchange before transmitting the handover instruction message to the synchronous exchange and includes the billing ID in the handover instruction message. The handover method according to any one of claims 1 to 6, wherein the handover is transmitted and includes an internal exchange circuit ID (Inter MSC Circuit ID).   The handover request message transmitted by the interlinkage operation unit to the synchronous exchange includes parameters including billing ID, ESN, internal exchange circuit ID and MIN, and the response message transmitted by the synchronous exchange to the interlinkage operation unit. The handover method according to claim 1, further comprising a parameter including CDMA channel data and a CDMA channel list.   The resource allocation completion message may further include a parameter including a message type, an RRC container, and a RAB list to be released, when the asynchronous exchange transmits a resource allocation completion message to the radio network controller. Item 7. The handover method according to any one of Items 1 to 6.   7. The handover method according to claim 1, wherein the access signal includes an invoke ID, an application protocol data unit (APDU), and selected radio resource information. After the stage in which the originating mobile communication terminal completes handover and the incoming mobile communication terminal responds,
When a call release request is received from an incoming or outgoing mobile communication terminal, the asynchronous exchange or synchronous exchange that has received the call release request transmits a trunk connection release and call release request message between the exchanges to the interoperating operation unit. 7. The trunk line set between the asynchronous exchange and the synchronous exchange is released by the interworking operation section responding to the response. The handover method as described. The call release request message includes a parameter including an internal switch circuit ID (Inter MSC Circuit ID) , a release reason, a billing ID, and a MIN, and the response message includes a parameter including a billing ID. The handover method according to claim 18.

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