Title of Invention

A METHOD FOR HANDOVER OF A DUAL-BAND DUAL MODE MOBILE COMMUNICATION TERMINAL IN A HYBRID MOBILE COMMUNICATION SYSTEM

Abstract

Disclosed is a method for handover of a mobile communication terminal by using an Interworking Interoperability Function (HF) unit for signal exchange between asynchronous and synchronous mobile switching centers and a protocol (ISUP) for message transmission between the mobile switching centers in a hybrid mobile communication system including both an asynchronous network and synchronous network.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See section 10, rule 13) "METHOD FOR HANDOVER OF MOBILE COMMUNICATION TERMINAL IN MIXED MOBILE COMMUNICATION NETWORK OF ASYNCHRONOUS AND SYNCHRONOUS COMMUNICATION NETWORK" SK TELECOM CO., LTD an Korean company of 11, Euljiro-2ga, Jung-gu, Seoul, 100-999, Korea The following specification particularly describes the invention and the manner in which it is to be performed. WO 2005/086385 PCT/KR2005/000682 Description METHOD FOR HANDOVER OF MOBILE COMMUNICATION TERMINAL IN MIXED MOBILE COMMUNICATION NETWORK OF ASYNCHRONOUS AND SYNCHRONOUS COMMUNICATION NETWORK Technical Field [1] The present invention relates to a method for handover in a mobile communication network, and more particularly to a method for handover of a mobile communication terminal by using an Interworking Interoperability Function (IIF) unit for signal exchange between asynchronous and synchronous mobile switching centers and a protocol (ISUP) for message transmission between the mobile switching centers in a hybrid mobile communication system including both an asynchronous network and a synchronous network. Background Art [2] According to development in mobile communication technologies, mobile com- munication networks have evolved through alternation of generations. In current mobile communication networks, it is common that a synchronous mobile communication system (CDMA mobile communication system) called 2nd or 2.5th generation mobile communication system and an asynchronous mobile communication system (WCDMA mobile communication system) called 3rd generation mobile communication system coexist. [3] Therefore, mobile communication terminals (e.g. A Dual Band Dual Mode (DBDM) Terminal), which can be used in networks having such a construction, is now being developed. With such a mobile communication terminal, a user can use different types of services in an asynchronous system area and a synchronous system area, respectively. Such a DBDM mobile communication terminal includes an antenna, a synchronous modem for a synchronous mobile communication service, an asynchronous modem for an asynchronous mobile communication service, and a common module. [4] However, the asynchronous mobile communication system is now in an initial stage of providing its service and requires an enormous investment for construction of the system. Therefore, the current asynchronous mobile communication system fails to provide service for a wide area and thus usually has a service area overlapping that of the synchronous mobile communication system. Due to such a limitation in the service area of the asynchronous mobile communication system, call connection may be in- 3 WO 2005/086385 PCT/KR2005/000682 terrupted when a subscriber of the asynchronous mobile communication system using the service of the asynchronous mobile communication system moves into an area of the synchronous mobile communication system which does not provide the asynchronous mobile communication service. Therefore, handover is necessary for continuous service provision in a system in which the asynchronous mobile communication system and the synchronous mobile communication system coexist, especially when the asynchronous mobile communication service area is smaller than the synchronous mobile communication system service area. Further, the handover is necessary not only when a mobile communication terminal is in communication but also in the cases where a mobile communication terminal originated a call is waiting for a response from a terminator of the call and where the terminating mobile communication terminal is in an alert state for the call termination. Disclosure of Invention Technical Problem Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a method for handover of a mobile communication terminal, which can provide continuous service without interruption of communication by using an Interworking Interoperability Function (ITF) unit for signal exchange between asynchronous and synchronous mobile switching centers and a protocol (ISUP) for message transmission between the mobile switching centers, when the mobile communication terminal moves into a synchronous mobile communication system area in a state in which the mobile communication terminal is using voice communication service. It is another object of the present invention to provide a method for handover of a mobile communication terminal, which performs the handover by using an In-terworking Interoperability Function (IIF) unit for signal exchange between asynchronous and synchronous mobile switching centers and a protocol (ISUP) for message transmission between the mobile switching centers, when the mobile communication terminal moves into a synchronous mobile communication system area in a state in which the mobile communication terminal is waiting for a response after originating a call or is in an alert state after the call is terminated. Technical Solution According to an aspect of the present invention, there is provided a method for handover of a dual-band dual-mode mobile communication terminal in a hybrid mobile communication system including both an asynchronous mobile communication system and a synchronous mobile communication system, the asynchronous mobile com- WO 2005/086385 PCI7KR2005/000682 munication system including a node B, a radio network controller and an asynchronous mobile switching center, the synchronous mobile communication system including a base transceiver station, a base station controller and a synchronous mobile switching center, the asynchronous mobile switching center and synchronous mobile switching center being interconnected through an interworking interoperability function (IIF) unit and each being connected :o a dual stack home location register (D-HLR), the mobile communication terminal being capable of communicating with both an asynchronous mobile communication system and a synchronous mobile communication system, the method comprising the steps of: (a) transmitting a handover request message to the asynchronous mobile switching center by the radio network controller in response to a handover request from the mobile communication terminal; (b) transmitting a handover request message to the EOF unit by the asynchronous mobile switching center; (c) requesting transmission of subscriber information and receiving the subscriber information from the D-HLR by the UF unit; (d) transmitting a handover instruction message to the synchronous mobile switching center from the UF unit and transmitting a handover instruction message to the base transceiver station/base station controller from the synchronous mobile switching center; (e) allocating a downlink traffic channel to the mobile communication terminal and transmitting a response message to the handover request to the synchronous mobile switching center by the base transceiver station/base station controller; (f) transmitting a response to the handover instruction message from the synchronous mobile switching center to the EF unit, transmitting a response message to the handover request from the IIF unit to the asynchronous mobile switching center, and setting a trunk line between the synchronous mobile switching center and the asynchronous mobile switching center; (g) transmitting an initial address message to the UF unit and receiving a response by the asynchronous mobile switching center, and completing trunk establishment between the synchronous mobile switching center and the asynchronous mobile switching center; (h) reporting to the radio network controller by the asynchronous mobile switching center that allocation of resources for the handover has been completed; (i) instructing the handover to the mobile communication terminal through the node B by the radio network controller; (j) switching a mode of the mobile communication terminal into a synchronous mobile switching center connection mode; (k) transmitting an access signal to the asynchronous mobile switching center by the UF unit; (1) transmitting frames and preambles through an uplink traffic channel to the base transceiver station/base station controller, thereby reporting completion of the handover by the mobile communication terminal; and (m) releasing connection between the asynchronous mobile communication system and the synchronous mobile communication system. WO 2005/086385 PCT/KR2005/000682 [9] According to other aspects of the present invention, the mobile communication terminal may be either in a state of voice communication or in an alert state for the call termination. [10] When the mobile communication terminal is in a state of waiting for a response to a call originated by the mobile communication terminal, the handover request message and the handover instruction message include information reporting that the mobile communication terminal is in the state of waiting for a response. [11] In this case, it is preferred that the method may further comprise the steps of: (n) reporting connection of a call-terminating mobile communication terminal to the EOF unit by the asynchronous mobile switching center, as the call-terminating mobile communication terminal responds; (o) transmitting an intersystem response message to the synchronous mobile switching center by the DDF unit and reporting to the base transceiver station/base station controller by the synchronous mobile switching center that the call-terminating mobile communication terminal has responded and connected to the synchronous mobile switching center; and (p) transmitting a response signal to the intersystem response message to the EOF unit by the synchronous mobile switching center. [12] When the mobile communication terminal is in an alert state for the call termination, the handover request message and the handover instruction message include information reporting that the mobile communication terminal is in the alert state for the call termination. [13] In this case, it is preferred that the method may further comprise the steps of: (q) reporting connection of the mobile communication terminal to the synchronous mobile switching center by the base transceiver station/base station controller, as the mobile communication terminal in the alert state for the call termination responds; (r) transmitting an intersystem response message from the synchronous mobile switching center to the HF unit and reporting to the asynchronous mobile switching center by the IIF unit that the mobile communication terminal has responded to an alert and connected to the synchronous mobile switching center; and (s) transmitting a response signal to the intersystem response message from the IIF unit to the synchronous mobile switching center. [14] Preferably, step (f) may comprise the steps of: transmitting an initial address message (IAM) from the asynchronous mobile switching center to the IIF unit, the IAM being an ISUP message; and transmitting an address completion message (ACM) from the IIF unit to the asynchronous mobile switching center, the ACM being an ISUP message. [15] Also, step (m) may comprise the steps of: reporting completion of the handover to the synchronous mobile switching center by the base transceiver station/base station WO 2005/086385 PCT/KR2005/000682 controller and reporting the completion of the handover to the IIF unit by the synchronous mobile switching center; requesting by the ITF unit to the asynchronous mobile switching center for release of connection and reporting by using an ISUP message connection between the synchronous mobile switching center and the mobile communication terminal; and releasing connection between the asynchronous mobile switching center and the node B/radio network controller. [16] The handover request message in step (a) comprises parameters including handover-related message used in the synchronous mobile communication system, neighbor cell information, neighbor base station information, message type, handover type, handover cause, source base station controller ID, target base station controller ID, Radio Access Bearer (RAB) information and wireless zone-related information. [17] The asynchronous mobile switching center determines with reference to the neighbor cell information and the neighbor base station information of the mobile communication terminal if the requested handover is handover between neighbor cells within the asynchronous mobile communication system or handover to the synchronous mobile communication system. [18] In step (b), the asynchronous mobile switching center transmits an asynchronous identifier number (MSISDN) of the mobile communication terminal together with the handover request message. [19] The subscriber information received by the IIF unit from the D-HLR includes a synchronous identifier (MIN, ESN) of the mobile communication terminal. [20] In in step (c), the HP unit requests transmission of the subscriber information by using one of a synchronous message and an asynchronous message. [21] The IIF unit generates a billing ID before transmitting the handover instruction message to the synchrono us mobile switching center and inserts the billing ID and an internal switching center circuit ID (InterMSCCircuitID) into the transmitted handover instruction message, the billing ID including an ID of a synchronous mobile switching center to which the asynchronous mobile switching center will connect. [22] The handover request message transmitted from the IIF unit to the synchronous mobile switching center comprises parameters including a billing ID, ESN, an internal switching center circuit ID and MIN, and the response message transmitted from the synchronous mobile switching center to the IIF unit comprises parameters including CDMA channel data and a CDMA channel list. [23] In step (h), a resource allocation completion message transmitted to the radio network controller from the asynchronous mobile switching center comprises a message type, an RRC container and an RAB list to be released. [24] The access signal comprises an invoke ID, an application protocol data unit (APDU) and selected radio resource information. 7 WO 2005/086385 PCT/KR2005/000682 [25] After the step in which the call-originating mobile communication terminal completes the handover and the call-terminating mobile communication terminal responds, upon receiving a request for call release from the call-originating mobile communication terminal or the call-terminating mobile communication terminal, the asynchronous mobile switching center transmits to the IIF unit a message requesting release of trunk connection and call connection between asynchronous and synchronous mobile switching centers, and the IIF unit responds to the message, so that the trunk between asynchronous and synchronous mobile switching centers is released. [26] The message requesting release of the call connection comprises parameters including an internal switching center circuit ID, cause of release, a billing ID and MIN, and a response message to the message requesting release of the call connection comprises a billing ID. [27] According to the present invention, in a hybrid mobile communication system including both an asynchronous network and a synchronous network, when a dual-mode dual-band mobile communication terminal moves from an area of an asynchronous mobile communication system to an area of a synchronous mobile communication system while being in a state of voice communication or waiting for a response to a call, or in an alert state for call termination, the handover is performed by using an Interworking Interoperability Function (HF) unit for signal exchange between asynchronous and synchronous mobile switching centers and an ISUP (a protocol for message transmission between mobile switching centers). Therefore, the present invention can provide a high quality service regardless of the generation of the mobile communication system. [28] Also, the present invention eliminates prevents construction of the asynchronous mobile communication system over an unnecessarily wide area and thus can reduce the investment necessary for design of the asynchronous mobile communication system. Brief Description of the Drawings [29] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: [30] FIG. 1 is a block diagram of a mobile communication network according to the present invention; [31] FIG. 2 is a block diagram for illustrating the concept of the handover of a mobile communication terminal during voice communication between an asynchronous network and a synchronous network according to the first embodiment of the present invention; WO 2005/086385 PCT/KR2005/000682 [32] FIG. 3 is a flowchart of a process for the handover of the mobile communication terminal during voice communication between an asynchronous network and a synchronous network according to the first embodiment of the present invention; [33] FIGs. 4 through 17 are views showing parameters included in messages used for the handover according to the present invention; [34] FIG. 18 is a block diagram for illustrating the concept of the handover of a mobile communication terminal in a state of waiting for a response to a call between an asynchronous network and a synchronous network according to the second embodiment of the present invention; [35] FIGs. 19 and 20 are a flowchart of a process for the handover of the mobile com- munication terminal in a state of waiting for a response to a call between an asynchronous network and a synchronous network according to the second embodiment of the present invention; [36] FIG. 21 is a view showing parameters included in messages used for the handover according to the present invention; [37] FIG. 22 is a block diagram for illustrating the concept of the handover of a mobile communication terminal in an alert state for call termination between an asynchronous network and a synchronous network according to the third embodiment of the present invention; and [38] FIGs. 23 and 24 are a flowchart of a process for the handover of the mobile com- munication terminal in an alert state for call termination between an asynchronous network and a synchronous network according to the third embodiment of the present invention. Best Mode for Carrying Out the Invention [39] Reference will now be made in detail to the preferred embodiments of the present invention. [40] Hereinafter, a method for handover of a mobile communication terminal in a hybrid mobile communication system including both an asynchronous network and a synchronous network according to the first embodiment of the present invention will be described with reference to accompanying drawings. [41] FIG. 1 is a block diagram of a mobile communication network according to the present invention. [42] The mobile communication terminal 10 according to the present invention is a Dual-Band Dual-Mode (I)BDM) mobile communication terminal capable of supporting both the asynchronous mobile communication service and the synchronous mobile communication service and includes a synchronous modem for the synchronous mobile communication service, an asynchronous modem for the 9 WO 2005/086385 PCT/KR2005/000682 asynchronous mobile communication service, and a common module. Therefore, the mobile communication terminal 10 can connect with either an asynchronous mobile communication system 20 or a synchronous mobile communication system 30 by wireless in order to use voice and data service provided by them. [43] The asynchronous mobile communication system 20 includes a node B/RNC 210, an asynchronous mobile switching center (MSC) 220, a General Packet Radio Service (GPRS) network 240, a serving GPRS Support Node (SGSN) 230, and a Gateway GPRS Support Node (GGSN) 250. The node B/RNC 210 represents a node B serving as a base station for supporting wireless communication with the mobile com- munication terminal 10 or an RNC (Radio Network Controller) 210 for controlling the node B for wireless communication with the mobile communication terminal 10. The asynchronous mobile switching center 220 is connected to the node B/RNC 210 and performs call exchange with the mobile communication terminal 10 through the node B/RNC 210 in order to provide service to the mobile communication terminal 10. The SGSN 230 is connected between the node B/RNC 210 and the GPRS network 240 to keep tracking the position of the mobile communication terminal 10 and perform an access control and a security function. The GGSN 250 is connected to the SGSN 230 through the GPRS network 240 and to an IP network 70 to support inter-working with outer systems for exchange of packet. [44] The synchronous mobile communication system 30 includes a BTS/BSC 310, a synchronous mobile switching center (MSC) 320, a PDSN 330, and a Data Core Network (DCN) 340. The BTS/BSC 310 represents a BTS (Base Transceiver Station) for supporting wireless communication with the mobile communication terminal 10 or a BSC (Base Station Controller) for controlling the BTS for wireless communication with the mobile communication terminal 10. The synchronous mobile switching center 320 is connected to and exchanges calls with at least one BSC. The PDSN 330 is connected to the BSC to provide a packet data service to subscribers. The DCN 340 supports connection between the PDSN 330 and the IP network 70. [45] Further, the mobile switching centers 220 and 320 of the asynchronous mobile com- munication system 20 and the synchronous mobile communication system 30 are inter connected through an Interworking Interoperability Function (TIF) unit 60. The BP unit 60 receives an asynchronous message from the asynchronous mobile switching center 220, converts the received asynchronous message to a synchronous message, and then transmits the converted synchronous message to the synchronous mobile switching center 320. Also, the IIF unit 60 constructs and manages a database for the synchronous mobile communication system information. [46] The asynchronous mobile switching center.220 and the synchronous mobile switching center 320 are interconnected through a No. 7 common signal network 40 WO 2005/086385 PCT/KR2005/000682 and are connected to a Dual stack Home Location Register (D-HLR) 50 through the No. 7 common signal network 40. The Dual stack Home Location Register 50 stores and manages asynchronous mobile communication system subscriber information of the DBDM mobile communication terminal 10 and corresponding synchronous mobile communication system subscriber information, so that the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 can refer to the information when performing works such as handover. [47] First Embodiment [48] The first embodiment of the present invention relates to a method for handover of a mobile communication terminal during a voice communication in a hybrid mobile communication system including both an asynchronous network and a synchronous network. [49] In the network having the construction described above, the mobile communication terminal 10 performing voice communication within the area of the asynchronous mobile communication system 20 periodically measures the intensity of the signal from a serving node B to which the mobile communication terminal 10 is currently connected and the intensity of the signal from neighbor node Bs adjacent to the serving node B and reports the measured intensities to the serving node B. In this case, the node B/RNC 210 transmits to the asynchronous mobile switching center 220 the report together with information of neighbor cells, base station IDs, etc., which have been detected by the mobile communication terminal 10. [50] Upon receiving a handover request message from the RNC, the asynchronous mobile switching center 220 determines with reference to the neighbor cells, base station IDs, etc., received from the RNC if the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20 or handover to the synchronous mobile communication system 30. [51] When the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20, the asynchronous mobile switching center 220 performs the handover between neighbor cells. In contrast, when the requested handover is handover to the synchronous mobile communication system 30, the asynchronous mobile switching center 220 causes the IIF unit 60 to perform the handover to the synchronous mobile communication system 30. For the handover, the IIF unit 60 converts an asynchronous message to a synchronous message and transmits the converted synchronous message to the synchronous mobile switching center 320. For this operation, it is necessary for the IIF unit 60 to construct and manage a database of the synchronous mobile communication system information in advance. The database includes information of switching centers, signal point, information of the trunk line in relation to a dedicated channel, etc. Based on the synchronous mobile WO 2005/086385 PCT/KR2005/000682 communication system information and the handover request from the asynchronous mobile switching center 220, the IIF unit 60 selects the target to be handovered, that is, the mobile switching center 220, and generates a billing ED including an ED of the handover target mobile switching center, which can be used in the handover process thereafter. [52] Hereinafter, a process of the handover will be described in detail with reference to FIGs. 2 and 3. [53] FIG. 2 is a block diagram for illustrating the concept of the handover when a mobile communication terminal performing voice communication in an asynchronous mobile communication system area moves to a synchronous mobile communication system area, and FIG. 3 is a flowchart of a process for the handover of the mobile communication terminal in voice communication. [54] As the mobile communication terminal 10 performing voice communication in the area of the asynchronous mobile communication system 20 moves to the area of the synchronous mobile communication system 30, the mobile communication terminal 10 detects a signal from the synchronous mobile communication system 30, periodically measures the intensities of the signals from a current serving node B of the asynchronous mobile communication system 20 and neighbor base stations (node Bs), and reports the measured intensities to the current serving node B. When the intensity of the signal from the current serving node B to which the mobile communication terminal 10 currently connects is lower than a predetermined value, the mobile communication terminal 10 transmits a handover request message (IU- Reloc Required) to the asynchronous mobile switching center 220 through the RNC (step S101). [55] This handover request message (IU Reloc Required) includes a handover-related message used in the synchronous mobile communication system. Here, the RNC transmits to the asynchronous mobile switching center 220, together with the handover request message, neighbor cell information, neighbor base station information (neighbor BS IDs), etc., which have been received from the mobile communication terminal 10. Based on this information, the asynchronous mobile switching center 220 determines if the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20 or handover to the synchronous mobile communication system 30. The handover request message (IU Reloc Required) transmitted from the RNC to the asynchronous mobile switching center 220 includes parameters such as message type, handover type, handover cause, source base station controller ID, target base station controller ED, Radio Access Bearer (RAB) information and wireless zone-related information, as shown in FIG. 4. Further, the RNC adds the handover-related information used in the synchronous mobile communication system to the parameter of 'Old BSS To New BSS Information' included in the WO 2005/086385 PCT/KR2005/000682 handover request message. FIG. 5 shows a list of the added handover-related in formation in detail. [56] Upon receiving the handover request message, the asynchronous mobile switching center 220 transmits an asynchronous message (MAP Prep Handover Req) requesting handover to the HF unit 60 (step S102). Here, an extension container is added to the asynchronous message, which is then transmitted together with an asynchronous identifier (MSISDN) of the mobile communication terminal 10. The asynchronous message includes parameters such as an invoke ED, a target cell ID, a target radio network controller ED, and an MSISDN, as shown in FIG. 6. [57] Thereafter, by referring to the received asynchronous subscriber information (MSISDN) from the asynchronous mobile switching center 220, the IIF unit 60 requests the D-HLR 50 to transmit subscriber information (Call Data Request) (step SI03). That is, the EOF unit 60 requests a synchronous network identifier (MTN, ESN) of the mobile communication terminal 10. In step S103, the EOF unit 60 may request synchronous network identifier information of a subscriber to the D-HLR 50 by using an asynchronous message (MAP_SEND_IMSI). [58] Upon receiving the request for the subscriber information, the D-HLR 50 refers to the database, extracts synchronous network identifier information (MIN, ESN) of the corresponding subscriber, and then transmits the extracted information to the IIF unit 60 (Call Data Req Ack) (step SI04). Here, the synchronous network message (Call Data Request) requesting the synchronous network identifier information of the subscriber includes parameters such as the billing ID and digits (i.e. MSISDN) as shown in FIG. 7, and the response message (Call Data Req Ack) includes parameters such as ESN, MEN, and MSCID. Meanwhile, when an asynchronous message (MAP_SEND_IMSI) is used in requesting the synchronous network identifier in formation of the subscriber, the asynchronous message (MAP_SEND_IMSI) includes parameters as shown in FIG. 8. [59] Upon receiving the subscriber information from the D-HLR 50, the IIF 60 instructs (Facilities Directive2) the handover to the synchronous mobile switching center 320 (step S105), and the synchronous mobile switching center 320 sends a handover request message (Handoff Request) to the BTS/BSC 310 (step S106). [60] Before transmitting the; handover instruction message (Facilities Directive2) to the synchronous mobile switching center 320, the IIF unit 60 produces a billing identifier (ED) and inserts it in the handover instruction message (Facilities Directive2). Also, the HF unit 60 inserts the internal switching center circuit ID (InterMSCCircuitID) into the transmitted handover instruction message (Facilities Directive2). The billing ED includes an ID of the synchronous mobile switching center 320 to which the asynchronous mobile switching center 220 will connect. WO 2005/086385 PCT/KR2005/000682 [61] Upon receiving the handover request message from the synchronous mobile switching center 320, the 3TS/BSC 310 transmits null frames (Forward Traffic Channel frames) through a downlink traffic channel to the synchronous modem of the mobile communication terminal 10, thereby enabling assignment of a downlink channel (step S107). Then, the BTS/BSC 310 transmits to the synchronous mobile switching center 320 a response message (Handoff Request Ack) in response to the handover request message from the synchronous mobile switching center 320 (step S108). Then, the synchronous mobile switching center 320 transmits to the asynchronous mobile switching center 220 a response message (Facilities Directive2 Ack) in response to the handover instruction message of step S102 (step S109). As a result, a trunk line between the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 is established. [62] To be more specific, the DF unit 60 sets a mapping relation between a physical trunk line and a dedicated channel which is an identifier for logical trunk line es- tablishment, sets this information as the internal switching center circuit ID (InterMSCCircuitID) of the handover instruction message (Facilities Directive2), and transmits the set ID to the synchronous mobile switching center 320. Thereafter, when the response message (Facilities Directive2 Ack) has been transmitted from the synchronous mobile switching center 320,, the trunk line between the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 is es- tablished. The handover instruction message (Facilities Directive2) transmitted between the EF unit 60 arid the synchronous mobile switching center 320 includes parameters such as a billing ID, an ESN, an internal switching center circuit ID and MTN, as shown in FIG. 9, and the response message (Facilities Directive2 Ack) thereof includes parameters such as CDMA channel data and a CDMA channel list. [63] Thereafter, the asynchronous mobile switching center 220 transmits an Initial Address Message (IAM) lo the HF unit 60, and the HF unit 60 transmits an Address Completion Message (ACM) in response to the IAM, so that the trunk line is set between the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 and she call can be routed through the trunk line (step Sill and S112). Messages for the trunk setting between the mobile switching centers are transmitted/received by the ISUP. [64] After the trunk line between switching centers is set in the way as described above, the asynchronous mobile switching center 220 reports to the node B/RNC 210 that resource allocation for the; handover has been completed (IU Relocation Command) (step SI 13). Upon receiving the report (IU Relocation Command), the node B/RNC 210 requests the asynchronous modem of the mobile communication terminal 10 to perform handover (Handover from UTRAN command) (step SI 14). Here, the message WO 2005/086385 PCT/KR2005/000682 (IU Relocation Command) reporting that resource allocation for the handover has been completed includes parameters including the message type, the RRC container, the RAB list to be released, etc. as shown in FIG. 10. Here, a handover message (HDM) is transmitted using an L3 parameter of the resource allocation completion report message. FIG. 11 shows a list of specific parameters in the handover message. [65] Thereafter, the asynchronous modem of the mobile communication terminal 10 transmits channel assignment information to the synchronous modem (step S115) and the IIF unit 60 requests an access signal (MAP Process Access Signaling Req) to the asynchronous mobile switching center 220 (step SI 16). The access signal contains an invoke ED, an Application Protocol Data Unit (APDU), selected radio resource information, etc. FIG. 12 shows a list of specific parameters in the access signal. [66] Further, the synchronous modem of the mobile communication terminal 10 transmits frames or preambles through an uplink traffic channel to the BTS/BSC 310 of the synchronous mobile communication system (step SI 17) and reports (Handoff Completion Message) that the handover has been completed (step SI 18). Upon receiving the report (Handoff Completion Message), the BTS/BSC 310 transmits a response signal (BS Ack Order) in response to the report (step SI 19). Then, the synchronous modem reports to the asynchronous modem that the call connection with the synchronous mobile communication system has been completely established (step S120). [67] Then, the BTS/BSC 310 reports to the synchronous mobile switching center 320 (Handoff Complete) that the handover has been completed (step S121), and the synchronous mobile switching center 320 reports to the ITF unit 60 (Mobile On Channel) that the handover has been completed (step S122). Upon receiving the report, the HF unit 60 requests the asynchronous mobile switching center 220 to release the connection (MAP Send End Signal Req) (step S123). [68] Further, the HF unit 60 transmits to the asynchronous mobile switching center 220 a message (ANSWER) reporting the connection between the mobile communication terminal and the synchronous mobile switching center 320 (step S124). Then, the connection between the asynchronous mobile switching center 220 and the node B/ RNC 210 is released (IU Release Command, IU Release Complete) (steps 125 and 126). [69] Here, the hand over completion message (Mobile On Channel) transmitted from the mobile switching center 320 to the IIF unit 60 includes parameters as shown in FIG. 13, and the connection release request message (MAP Send End Signal Req) transmitted from the EDF unit 60 to the asynchronous mobile switching center 220 includes parameters as shown in FIG. 14. Further, the messages (IU Release Command, IU Release Complete) transmitted for release of connection between the WO 2005/086385 PCT/KR2005/000682 node B/RNC and the asynchronous mobile switching center 220 includes parameters as shown in FIGs. 15 and 16. [70] A process of releasing the call connection after the handover of the mobile com- munication terminal performing voice communication in the area of the asynchronous mobile communication system into the synchronous mobile communication system ha: been completed according to the process described above will be briefly discussed below. The release of the call connection may be first requested by either a mobile communication terminal of a subscriber still located within the area of the asynchronous mobile communication system or a mobile communication terminal of a subscriber already handovered to the area of the synchronous mobile communication system. In the present embodiment, description is given of the case where the release of the call connection has been requested by the mobile communication terminal of the subscriber still located within the area of the asynchronous mobile communication system. [71] As the mobile communication terminal releases the call, the call connection between the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 is released (Call Release) (step SI27) and the trunk connection between the mobile switching centers is released (Release) (step SI28). Thereafter, the asynchronous mobile switching center 220 reports to the IIF unit 60 that the release of the connection has been completed (MAP Send End Signal Resp) (step SI29), and the IIF unit 60 transmits a cal I release request message (Facilities Release) to the synchronous mobile switching center 320 (step S130). When the synchronous mobile switching center 320 sends a response (Facilities Ack) to the request message, the trunk line set between the mobile switching centers is released (step S131). Here, the call release request message (Facilities Release) includes, as shown in FIG. 17, parameters including an internal MSC circuit ID, a release reason, a billing ID, MIN, etc., and the response message (Facilities Ack) includes parameters including a billing ID, etc. [72] In the present embodiment, the asynchronous mobile switching center determines if the requested handover is handover between neighbor cells within the asynchronous mobile communication system or handover to the synchronous mobile communication system. When it is determined that the requested handover is handover to the synchronous mobile communication system, handover is performed in such a manner that messages are exchanged between the synchronous mobile switching center and the asynchronous mobile switching center by using an ISUP (a protocol for message transmission between mobile switching centers) while the HF unit functions as a converter. For this operation, it is necessary for the IIF unit to construct and manage a database of the synchronous mobile communication system information in advance. WO 2005/086385 PCT/KR2005/000682 [73] Second Embodiment [74] The second embodiment of the present invention relates to a method for handover of a mobile communication terminal in a state of waiting for a response to a call in a hybrid mobile communication system including both an asynchronous network and a synchronous network. [75] Hereinafter, a method for handover of a. mobile communication terminal 10 when the mobile communication terminal 10 is located within the area of the asynchronous mobile communication system 20 and waits for a response after originating a call in the network having the construction described above will be described with reference to FIG. 18. [76] FIG. 18 is a block diagram for illustrating the concept of the handover of a call- originating mobile communication terminal waiting for a response to the originated call between an asynchronous network and a synchronous network according to the second embodiment of the; present invention, in which the mobile communication terminals include a call-originating mobile communication terminal 10a and a call- terminating mobile communication terminal 10b. [77] When the call-terminating mobile communication terminal 10b is in a state of call- termination alert by the node B/RNC 210 according to the call origination by the call- originating mobile communication terminal 10a and the call-originating mobile com- munication terminal 10a moves into the overlap area C between the synchronous and asynchronous mobile communication systems or the area B of the synchronous mobile communication system, the call-originating mobile communication terminal 10a requests handover to the node B of the asynchronous mobile communication system 20, and then the node B requests handover through the RNC to the asynchronous mobile switching center 220. [78] Then, the handover of the call-originating mobile communication terminal 10a between the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 is started. When the handover is completed and the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 are interconnected through the IIF unit 60, the call-originating mobile com- munication terminal 10a connects with the synchronous mobile communication system 30 through the BTS/BSC 310 and waits for a response from the call-terminating mobile communication terminal 10b. [79] For the handover of a. mobile communication terminal in a state of waiting for a response to a call, the mobile communication terminal 10a periodically measures the intensity of the signal from a serving node B to which the mobile communication terminal 10 is currently connected and the intensity of the signal from neighbor node Bs adjacent to the serving node B and reports the measured intensities to the serving WO 2005/086385 PCT/KR2005/000682 . node B. In this case, the node B/RNC 210 transmits to the asynchronous mobile switching center 220 the report together with information of neighbor cells, base station IDs, etc., which have been detected by the mobile communication terminal 10a. [80] Upon receiving a handover request message from the RNC, the asynchronous mobile switching center 220 determines with reference to the neighbor cells, base station IDs, etc., received from the RNC if the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20 or handover to the synchronous mobile communication system 30. [81] When the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20, the asynchronous mobile switching center 220 performs the handover between neighbor cells. In contrast, when the requested handover is handover to the synchronous mobile communication system 30, the asynchronous mobile switching center 220 causes the HP unit 60 to perform the handover to the synchronous mobile communication system 30. For the handover, the DP unit 60 converts an asynchronous message to a synchronous message and transmits the converted synchronous message to the synchronous mobile switching center 320. For this operation, it is necessary for the HF unit 60 to construct and manage a database of the synchronous mobile communication system information in advance. The database includes information of switching centers, signal point, information of the trunk line in relation to a dedicated channel, etc. Based on the synchronous mobile communication system information and the handover request from the asynchronous mobile switching center 220, the DP unit 60 selects the target to be handovered, that is, the mobile switching center 220, and generates a billing ID including an ID of the handover target mobile sv/itching center, which can be used in the handover process thereafter. Further, the DP unit 60 sets a trunk between the asynchronous mobile switching center 220 and the synchronous mobile switching center 320, so that the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 can exchange messages by using an ISUP which is a message transmission protocol between mobile switching centers. [82] Hereinafter, a process of the handover of a mobile communication terminal in a state of waiting for a call response will be described in more detail with reference to FIGs. 19 and 20. [83] FIGs. 19 and 20 illustrate a flowchart of the process for the handover of the mobile communication terminal in a state of waiting for a call response from the asynchronous network to the synchronous network according to the second embodiment of the present invention. The asynchronous modem and the synchronous modem shown in FIGs. 19 and 20 are modems of the call-originating mobile communication terminal 10a. WO 2005/086385 PCT/KR2005/000682 [84] As the mobile communication terminal 10a located in the area of the asynchronous mobile communication system 20 moves toward the area of the synchronous mobile communication system 3C after originating a call to the mobile communication terminal 10b also located in the area of the asynchronous mobile communication system 20 and is then located within the overlap area C between the asynchronous mobile communication system area and the synchronous mobile communication system area, the mobile communication terminal 10a detects a signal from the synchronous mobile communication system 30, periodically measures the intensities of the signals from a current serving node B of the asynchronous mobile communication system 20 and neighbor base stations (node Bs), and reports the measured intensities to the current serving node B. When the intensity of the signal from the current serving node B to which the mobile communication terminal 10a currently connects is lower than a predetermined value, the mobile communication terminal 10a transmits a handover request message (IU- Reloc Required) to the asynchronous mobile switching center 220 through the RNC (step S201). [85] A successive process (steps S201 - S226 in FIGs. 19 and 20) in which the handover is performed in response to the handover request and connection is then released according to a request for release of the connection are in fact the same as those (steps S10l - S126 in FIG. 3) according to the first embodiment of the present invention, so a detailed description thereof is omitted here. [86] However, in the second embodiment of the present invention, when the asynchronous mobile switching center 220 transmits an asynchronous message (MAP Prep Handover Req) requesting handover to the DF unit 60 in response to the received handover request message (step S202), an extension container is added to the asynchronous message, which is then transmitted together with an asynchronous identifier (MSISDN) of the mobile communication terminal 10a and a report that the mobile communication terminal 10a is in a state of waiting the response. For this operation, the status of the mobile communication terminal 10a must be expressed by using the parameters included in the handover request message (MAP Prep Handover Req). This message (MAI5 Prep Handover Req) includes parameters such as an invoke ID, a target cell ED, a target radio network controller ED, and an MSISDN, as shown in FIG.6. [87] The handover instruction message (Facilities Directive2) transmitted between the IIF unit 60 and the synchronous mobile switching center 320 includes parameters such as a billing ID, an ESN, an internal switching center circuit ED, MEN, and handoff status, as shown in FIG. 9. Especially, the parameter Handoff status is an identifier representing that the mobile communication terminal is in the state of waiting a response. Also, the response message (Facilities Directive2 Ack) thereof includes parameters 19 WO 2005/086385 PCT/KR2005/000682 such as CDMA channel data and a CDMA channel list. [88] When the handover of the mobile communication terminal 10a into the synchronous mobile communication system from the state of waiting a response has been completed through the above-mentioned process, the call is established between the call-terminating mobile communication terminal in die asynchronous mobile communication system area, the asynchronous mobile switching center, the IIF unit, the synchronous mobile switching center, and the call-originating mobile communication terminal. [89] Thereafter, when the call-terminating mobile communication terminal 10b responds, the node B/RNC connected to the call-terminating mobile communication terminal 10b reports it to the asynchronous mobile switching center 220 (BICC or ISUP ANSWER) (step S227), and the asynchronous mobile switching center 220 transmits a downlink access signal to the IIF unit 60 (MAP Forward Access Signaling Req) (step S228). [90] Then, the IIF unit 60 recognizes the response from the call-terminating mobile com- munication terminal 10b and transmits an intersystem response message (Intersystem Answer) to the synchronous mobile switching center 320 (step S229). Thereafter, the synchronous mobile switching center 320 reports the response of the call-terminating mobile communication terminal 10b to the BTS/BSC 310 (Progress) (step S230), and transmits to the IIF unit 63 a response message (Intersystem Answer Ack) responding to the intersystem response message (S231). [91] The intersystem response message includes parameters as shown in FIG. 21, which include internal MSC circuit ID, MIN, ESN, etc. [92] Through the above-mentioned process, the handover of the mobile communication terminal into the synchronous mobile communication system from the state of waiting a response is completed. Then, the call-terminating mobile communication terminal responds to the call from the call-originating mobile communication terminal, so that communication between the call-originating mobile communication terminal and the call-terminating mobile communication terminal is started and the call is released after the communication. The process of releasing the call is the same as in the first embodiment, so detailed description thereof is omitted here. [93] In the present embodiment, as the mobile communication terminal moves from the asynchronous area to the synchronous area while being in the state of waiting for a response to a call, the RNC requests handover to the asynchronous mobile switching center and the asynchronous mobile switching center determines if the requested handover is handover between neighbor cells within the asynchronous mobile communication system or handover to the synchronous mobile communication system. When it is determined that the requested handover is handover to the synchronous WO 2005/086385 PCT/KR2005/000682 mobile communication system, handover is performed in such a manner that messages are exchanged between the synchronous mobile switching center and the asynchronous mobile switching center by using an ISUP (a protocol message transmission between mobile switching centers) while the HF unit functions as a converter. Then, the fact that the mobile communication terminal to be handovered is in the state of waiting for a response is reported. [94] When the handover to the synchronous mobile communication system is completed and the call-terminating mobile communication terminal responds to the call, the asynchronous mobile switching center reports to the IIF unit that the call-terminating mobile communication terminal has responded. Then, the DDF unit transmits an in- tersystem response message to the asynchronous mobile switching center, thereby reporting that the call-terminating mobile communication terminal has responded to the alerting. Then, the handover is completed. [95] Third Embodiment [96] The third embodiment of the present invention relates to a method for handover of a mobile communication terminal in an alert state for call termination in a hybrid mobile communication system including both an asynchronous network and a synchronous network. [97] Hereinafter, a method for handover of a mobile communication terminal 10 which is located within the area of the asynchronous mobile communication system 20 and is in an alert state for call termination in the network having the construction described above will be described with reference to FIG. 22. [98] FIG. 22 is a block diagram for illustrating the concept of the handover of a mobile communication terminal in an alert state for call termination between an asynchronous network and a synchronous network according to the third embodiment of the present invention, in which the mobile communication terminals include a call-originating mobile communication terminal 10a and a call-terminating mobile communication terminal 10b. [99] When the call-terminating mobile communication terminal 10b is in a state of call- termination alert by the node B/RNC 210 according to the call origination by the call-originating mobile communication terminal 10a in the area A of the asynchronous mobile communication : system and the call-terminating mobile communication terminal 10b moves into the overlap area C between the synchronous and asynchronous mobile communication systems or the area B of the synchronous mobile communication system, the call-terminating mobile communication terminal 10b requests handover to the node B of tie asynchronous mobile communication system 20, and then the node B requests handover through the RNC to the asynchronous mobile switching center 220. 21 WO 2005/086385 PCT/KR2005/000682 [100] Then, the handover of the call-terminating mobile communication terminal 10b between the asynchronous mobile communication system 20 and the synchronous mobile communication system 30 is started. When the handover is completed and the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 are interconnected through the HF unit 60, the call origination alert by the call-originating mobile communication terminal 10a is transmitted through the BTS/ BSC 310 of the synchronous mobile communication system 30 to the call-terminating mobile communication terminal 10b. [101] For the handover of a mobile communication terminal in such an alert state for call termination, the mobile communication terminal 10b periodically measures the intensity of the signal from a serving node B to which the mobile communication terminal 10b is currently connected and the intensity of the signal from neighbor node Bs adjacent to the serving node B and reports the measured intensities to the serving node B. In this case, the node B/RNC 210 transmits to the asynchronous mobile switching center 220 the report together with information of neighbor cells, base station IDs, etc., which have been detected by the mobile communication terminal 10a. [102] Upon receiving a handover request message from the RNC, the asynchronous mobile switching center 220 determines with reference to the neighbor cells, base station IDs, etc., received from the RNC if the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20 or handover to the synchronous mobile communication system 30. [103] When the requested handover is handover between neighbor cells within the asynchronous mobile communication system 20, the asynchronous mobile switching center 220 performs the handover between neighbor cells. In contrast, when the requested handover is handover to the synchronous mobile communication system 30, the asynchronous mobile switching center 220 causes the IIF unit 60 to perform the handover to the synchronous mobile communication system 30. For the handover, the DF unit 60 converts an asynchronous message to a synchronous message and transmits the converted synchronous message to the synchronous mobile switching center 320. For this operation, it is necessary for the ITF unit 60 to construct and manage a database of the synchronous mobile communication system information in advance. The database includes information of switching centers, signal point, information of the trunk line in relation to a dedicated channel, etc. Based on the synchronous mobile communication system information and the handover request from the asynchronous mobile switching center 220, the IIF unit 60 selects the target to be handovered, that is, the mobile switching center 220, and generates a billing ID including an ED of the handover target mobile switching center, which can be used in the handover process thereafter. Further, the IIF unit 60 sets a trunk between the asynchronous mobile 22 WO 2005/086385 PCT/KR2005/000682 switching center 220 and the synchronous mobile switching center 320, so that the asynchronous mobile switching center 220 and the synchronous mobile switching center 320 can exchange messages by using an ISUP which is a message transmission protocol between mobile switching centers. [104] Hereinafter, a process of the handover of a mobile communication terminal in an alert state for call termination will be described in more detail with reference to FIGs. 23 and 24. [105] FIGs. 23 and 24 illustrate a flowchart of the process for the handover of the mobile communication terminal in an alert state for call termination from the asynchronous network to the synchronous network according to the third embodiment of the present invention. The asynchronous modem and the synchronous modem shown in FIGs. 23 and 24 are modems of the call-terminating mobile communication terminal 10b. [106] As the mobile communication terminal 10b in an alert state for call termination in the area of the asynchronous mobile communication system 20 moves toward the area of the synchronous mobile communication system 30 and is then located within the overlap area C between the asynchronous mobile communication system area and the synchronous mobile communication system area, the mobile communication terminal 10b detects a signal from the synchronous mobile communication system 30, periodically measures the intensities of the signals from a current serving node B of the asynchronous mobile communication system 20 and neighbor base stations (node Bs), and reports the measured intensities to the current serving node B. When the intensity of the signal from the current serving node B to which the mobile communication terminal 10b currently connects is lower than a predetermined value, the mobile communication terminal 10b transmits a handover request message (IU- Reloc Required) to the asynchronous mobile switching center 220 through the RNC (step S301). [107] A successive process (steps S301 ~ S326 in FIGs. 23 and 24) in which the handover is performed in response to the handover request and connection is then released according to a request for release of the connection are in fact the same as those (steps S101 ~ S126 in FIG. 3) according to the first embodiment of the present invention, so a detailed description thereof is omitted here. [108] However, in the third embodiment of the present invention, when the asynchronous mobile switching center 220 transmits an asynchronous message (MAP Prep Handover Req) requesting handover to the IIF unit 60 in response to the received handover request message (step S302), an extension container is added to the asynchronous message, which is then transmitted together with an asynchronous identifier (MSISDN) of the mobile communication terminal 10b and a report that the mobile communication terminal 1.0b is in an alert state for call termination. For this operation, the status of the mobile communication terminal 10b must be expressed by using the WO 2005/086385 PCT/KR2005/000682 parameters included in the handover request message (MAP Prep Handover Req). This message (MAP Prep Handover Req) includes parameters such as an invoke ID, a target cell ID, a target radio network controller ID, and an MSISDN, as shown in FIG. 6. [109] The handover instruction message (Facilities Directive2) transmitted between the HF unit 60 and the synchronous mobile switching center 320 includes parameters such as a billing ID, an ESN, an internal switching center circuit ID, MIN, and handoff status, as shown in FIG. 9. Especially, the parameter Handoff status is an identifier representing that the mobile communication terminal is in the alert state for call termination. Also, the response message (Facilities Directive2 Ack) thereof includes parameters such as CDMA channel data and a CDMA channel list. [110] When the handover of the mobile communication terminal 10b in the alert state for call termination into the synchronous mobile communication system has been completed through the above-mentioned process, the call is established between the call-originating mobile communication terminal in the asynchronous mobile communication system area, the asynchronous mobile switching center, the IIF unit, the synchronous mobile switching center, and the call-terminating mobile communication terminal. [Ill] Thereafter, when the c; ill-terminating mobile communication terminal 10b responds, the BTS/BSC 310 reports it to the synchronous mobile switching center 320 (Connect) (step S327), and the synchronous mobile switching center 320 transmits an intersystem response message (Intersystem Answer) to the HF unit 60, thereby reporting that the call-terminating mobile communication terminal 10b has responded (step S328). Then, the IIF unit 60 transmits an access signal (MAP Forward Access Signaling Req) to the asynchronous mobile switching center 220, thereby reporting the response from the call-terminating mobile communication terminal 10b (step S329), Thereafter, the IIF unit 60 transmits to the the synchronous mobile switching center 320 a response message (Intersystem Answer Ack) responding to the intersystem response message (S330). [112] The intersystem response message (Intersystem Answer) includes parameters as shown in FIG. 21, which include internal MSC circuit ID, MIN, ESN, etc. [113] Through the above-mentioned process, the handover of the mobile communication terminal in an alert state for call termination into the synchronous mobile communication system is completed. Then, the call-terminating mobile communication terminal responds to the call from the call-originating mobile communication terminal, so that communication between the call-originating mobile communication terminal and the call-terminating mobile communication terminal is started and the call is released after the communication. The process of releasing the call is the same as in the first embodiment, so detailed description thereof is omitted here. 24 WO 2005/086385 PCT/KR2005/000682 [114] In the present embodiment, as the mobile communication terminal moves from the asynchronous area to the synchronous area while being in the alert state for call termination, the RNC requests handover to the asynchronous mobile switching center and the asynchronous mobile switching center determines if the requested handover is handover between neighbor cells within the asynchronous mobile communication system or handover to the synchronous mobile communication system. When it is determined that the requested handover is handover to the synchronous mobile communication system, handover is performed in such a manner that messages are exchanged between the synchronous mobile switching center and the asynchronous mobile switching center by using an ISUP (a protocol message transmission between mobile switching centers) while the IIF unit functions as a converter. Then, the fact that the mobile communication terminal to be handovered is in the alert state for call termination is reported. [115] When the handover to the synchronous mobile communication system is completed and the call-terminating mobile communication terminal responds to the call, the asynchronous mobile switching center reports to the IIF unit that the call-terminating mobile communication terminal has responded. Then, the IIF unit transmits an in-tersystem response message to the asynchronous mobile switching center, thereby reporting that the call-terminating mobile communication terminal has responded to the alerting. Then, the handover is completed. Industrial Applicability [116] According to the present invention, in a hybrid mobile communication system including both an asynchronous network and a synchronous network, when a dual-mode dual-band mobile communication terminal moves from an area of an asynchronous mobile communication system to an area of a synchronous mobile communication system while being in a state of voice communication or waiting for a response to a call, or in an alert state for call termination, the handover is performed by using an Interworking Interoperability Function (IIF) unit for signal exchange between asynchronous and synchronous mobile switching centers and an ISUP (a protocol for message transmission between mobile switching centers). Therefore, the present invention can provide a high quality service regardless of the generation of the mobile communication system. [117] Also, the present invention eliminates prevents construction of the asynchronous mobile communication system over an unnecessarily wide area and thus can reduce the investment necessary for design of the asynchronous mobile communication system. [118] While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood WO 2005/086385 PCT/KR2005/000682 that the invention is not limited to the disclosed embodiment and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims. 27 WO 2005/086385 PCT/KR2005/000682 (h) reporting to the radio network controller by the asynchronous mobile switching center that allocation of resources for the handover has been completed; (i) instructing the handover to the mobile communication terminal through the node B by the radio network controller; (j) switching a mode of the mobile communication terminal into a synchronous mobile switching center connection mode; (k) transmitting an access signal to the asynchronous mobile switching center by the ECF unit; (1) transmitting frames and preambles through an uplink traffic channel to the base transceiver station/base station controller, thereby reporting completion of the handover by the mobile communication terminal; and (m) releasing connection between the asynchronous mobile communication system and the synchronous mobile communication system. [2] The method as claimed in claim 1, wherein the mobile communication terminal is in a state of voice communication. [3] The method as claimed in claim 1, wherein the mobile communication terminal is in a state of waiting for a response to a call originated by the mobile communication terminal, and the handover request message and the handover instruction message include information reporting that the mobile communication terminal is in the state of waiting for a response. [4] The method as claimed in claim 3, further comprising the steps of: (n) reporting connection of a call-terminating mobile communication terminal to the IIF unit by the asynchronous mobile switching center, as the call-terminating mobile communication terminal responds; (o) transmitting an intersystem response message to the synchronous mobile switching center by the ECF unit and reporting to the base transceiver station/base station controller by the synchronous mobile switching center that the call-terminating mobile communication terminal has responded and connected to the synchronous mobile switching center; and (p) transmitting a response signal to the intersystem response message to the HF unit by the synchronous mobile switching center. [5] The method as claimed in claim 1, wherein the mobile communication terminal is in an alert state for the call termination, and the handover request message and the handover instruction message include information reporting that the mobile communication terminal is in the alert state for the call termination. [6] The method as claimed in claim 3, further comprising the steps of: (q) reporting connection of the mobile communication terminal to the 28 WO 2005/086385 PCT/KR2005/000682 synchronous mobile switching center by the base transceiver station/base station controller, as the mobile communication terminal in the alert state for the call termination responds; (r) transmitting an intersystem response message from the synchronous mobile switching center to the IIF unit and reporting to the asynchronous mobile switching center by the IIF unit that the mobile communication terminal has responded to an alert and connected to the synchronous mobile switching center; and (s) transmitting a response signal to the intersystem response message from the IIF unit to the synchronous mobile switching center. [7] The method as claimed in one of claims 1 through 6, wherein step (f) comprises the steps of: transmitting an initial address message (IAM) from the asynchronous mobile switching center to the IIF unit, the IAM being an ISUP message; and transmitting an address completion message (ACM) from the IIF unit to the asynchronous mobile switching center, the ACM being an ISUP message. [8] The method as claimed in one of claims 1 through 6, wherein step (m) comprises the steps of: reporting completion of the handover to the synchronous mobile switching center by the base transceiver station/base station controller and reporting the completion of the handover to the IEF unit by the synchronous mobile switching center; requesting by the IIF unit to the asynchronous mobile switching center for release of connection and reporting by using an ISUP message connection between the synchronous mobile switching center and the mobile communication terminal; and releasing connection between the asynchronous mobile switching center and the node B/radio network controller. [9] The method as claimed in one of claims 1 through 6, wherein the handover request message in step (a) comprises parameters including handover-related message used in the synchronous mobile communication system, neighbor cell information, neighbor base station information, message type, handover type, handover cause, source base station controller ID, target base station controller ED, Radio Access Bearer (RAB) information and wireless zone-related information. [10] The method as claimed in claim 9, wherein the asynchronous mobile switching center determines with reference to the neighbor cell information and the neighbor base station information of the mobile communication terminal if the WO 2005/086385 PCT/KR2005/000682 requested handover is handover between neighbor cells within the asynchronous mobile communication system or handover to the synchronous mobile com- munication system. [11] The method as claimed in one of claims 1 through 6, wherein, in step (b), the asynchronous mobile switching center transmits an asynchronous identifier number (MSISDN) of the mobile communication terminal together with the handover request message. [12] The method as claimed in one of claims 1 through 6, wherein the subscriber in- formation received by the IIF unit from the D-HLR includes a synchronous identifier (MIN, ESN) of the mobile communication terminal. [13] The method as claimed in one of claims 1 through 6, wherein, in step (c), the IIF unit requests transmission of the subscriber information by using one of a synchronous message and an asynchronous message. [14] The method as claimed in one of claims 1 through 6, wherein the IIF unit generates a billing ID before transmitting the handover instruction message to the synchronous mobile switching center and inserts the billing ID and an internal switching center circuit ID (InterMSCCircuitID) into the transmitted handover instruction message, the billing ID including an ID of a synchronous mobile switching center to which the asynchronous mobile switching center will connect. [15] The method as claimed in one of claims 1 through 6, wherein the handover request message transmitted from the IIF unit to the synchronous mobile switching center comprises parameters including a billing ID, ESN, an internal switching center circuit ID and MIN., and the response message transmitted from the synchronous mobile switching center to the IIF unit comprises parameters including CDMA channel data and a CDMA channel list. [16] The method as claimed in one of claims 1 through 6, wherein, in step (h), a resource allocation completion message transmitted to the radio network controller from the asynchronous mobile switching center comprises a message type, an RRC container and an RAB list to be released. [17] The method as claimed in one of claims 1 through 6, wherein the access signal comprises an invoke ID, an application protocol data unit (APDU) and selected radio resource information. [18] The method as claimed in one of claims 1 through 6, wherein, after the step in which the call-originating mobile communication terminal completes the handover and the call-terminating mobile communication terminal responds, upon receiving a request for call release from the call-originating mobile communication terminal or the call-terminating mobile communication terminal, the 30 WO 2005/086385 PCT/KR2005/000682 asynchronous mobile switching center transmits to the DF unit a message requesting release of trunk connection and call connection between asynchronous and synchronous mobile switching centers, and the EOF unit responds to the message, so that the trunk between asynchronous and synchronous mobile switching centers is released. [19] The method as claimed in claim 18, wherein the message requesting release of the call connection comprises parameters including an internal switching center circuit ID, cause of release, a billing ID and MIN, and a response message to the message requesting release of the call connection comprises a billing ID. [20] A method for handover of a dual-band dual-mode mobile communication terminal comprising of hybrid mobile communication system substantially as herein described with reference to accompanying drawings. Dated this 5th day of October, 2006 31 ABSTRACT Declosed is a method for handover of a mobile communication terminal by using an Interworking Interoperability Function (HF) unit for signal exchange between asynchronous and synchronous mobile switching centers and a protocol (ISUP) for message transmission between the mobile switching centers in a hybrid mobile communication system including both an asynchronous network and synchronous network.

Documents:

1201-MUMNP-2006-ABSTRACT(1-8-2012).pdf

1201-mumnp-2006-abstract.doc

1201-mumnp-2006-abstract.pdf

1201-MUMNP-2006-CHINA DOCUMENT(1-8-2012).pdf

1201-mumnp-2006-claims(9-10-2006).pdf

1201-MUMNP-2006-CLAIMS(AMENDED)-(1-8-2012).pdf

1201-MUMNP-2006-CLAIMS(MARKED COPY)-(1-8-2012).pdf

1201-mumnp-2006-correspondence(23-4-2008).pdf

1201-mumnp-2006-correspondence-received.pdf

1201-mumnp-2006-description (complete).pdf

1201-mumnp-2006-description(complete)-(9-10-2006).pdf

1201-MUMNP-2006-DRAWING(1-8-2012).pdf

1201-mumnp-2006-drawings.pdf

1201-MUMNP-2006-FORM 1(1-8-2012).pdf

1201-mumnp-2006-form 1(10-5-2007).pdf

1201-MUMNP-2006-FORM 13(1-8-2012).pdf

1201-mumnp-2006-form 18(10-3-2008).pdf

1201-mumnp-2006-form 2(9-10-2006).pdf

1201-MUMNP-2006-FORM 2(TITLE PAGE)-(1-8-2012).pdf

1201-mumnp-2006-form 2(title page)-(9-10-2006).pdf

1201-MUMNP-2006-FORM 26(1-8-2012).pdf

1201-mumnp-2006-form 26(10-5-2007).pdf

1201-MUMNP-2006-FORM 3(1-8-2012).pdf

1201-mumnp-2006-form-1.pdf

1201-mumnp-2006-form-13.pdf

1201-mumnp-2006-form-2.doc

1201-mumnp-2006-form-2.pdf

1201-mumnp-2006-form-3.pdf

1201-mumnp-2006-form-5.pdf

1201-mumnp-2006-form-pct-isa-237.pdf

1201-MUMNP-2006-JAPANESE DOCUMENT(1-8-2012).pdf

1201-mumnp-2006-pct-search report.pdf

1201-MUMNP-2006-PETITION UNDER RULE 137(1-8-2012).pdf

1201-MUMNP-2006-REPLY TO EXAMINATION REPORT(1-8-2012).pdf

1201-mumnp-2006-wo international publication report(9-10-2006).pdf

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